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Kang Q, Jia J, Dean ED, Yuan H, Dai C, Li Z, Jiang F, Zhang XK, Powers AC, Chen W, Li M. ErbB3 is required for hyperaminoacidemia-induced pancreatic α cell hyperplasia. J Biol Chem 2024:107499. [PMID: 38944125 DOI: 10.1016/j.jbc.2024.107499] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2024] [Revised: 05/18/2024] [Accepted: 06/02/2024] [Indexed: 07/01/2024] Open
Abstract
Blood amino acid levels are maintained in a narrow physiological range. The pancreatic α cells have emerged as the primary aminoacidemia regulator through glucagon secretion to promote hepatic amino acid catabolism. Interruption of glucagon signaling disrupts the liver - α cells axis leading to hyperaminoacidemia, which triggers a compensatory rise in glucagon secretion and α cell hyperplasia. The mechanisms of hyperaminoacidemia-induced α cell hyperplasia remain incompletely understood. Using a mouse α cell line and in vivo studies in zebrafish and mice, we found that hyperaminoacidemia-induced α cell hyperplasia requires ErbB3 signaling. In addition to mTORC1, another ErbB3 downstream effector STAT3 also plays a role in α cell hyperplasia. Mechanistically, ErbB3 may partner with ErbB2 to stimulate cyclin D2 and suppress p27 via mTORC1 and STAT3. Our study identifies ErbB3 as a new regulator for hyperaminoacidemia-induced α cell proliferation and a critical component of the liver-α cells axis that regulates aminoacidemia.
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Affiliation(s)
- Qi Kang
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen 361102, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, China
| | - Jianxin Jia
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen 361102, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, China
| | - E Danielle Dean
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232; Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University, Nashville, TN 37232
| | - Hang Yuan
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen 361102, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, China
| | - Chunhua Dai
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232; Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University, Nashville, TN 37232
| | - Zhehui Li
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen 361102, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, China
| | - Fuquan Jiang
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen 361102, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, China
| | - Xiao-Kun Zhang
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen 361102, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, China
| | - Alvin C Powers
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232; Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University, Nashville, TN 37232
| | - Wenbiao Chen
- Departments of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN 37232.
| | - Mingyu Li
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen 361102, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen 361102, China; State Key Laboratory of Vaccines for Infectious Diseases, Xiang An Biomedicine Laboratory, Xiamen University, Xiamen 361102, China.
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McGlone ER, Tan TMM. Glucagon-based therapy for people with diabetes and obesity: What is the sweet spot? Peptides 2024; 176:171219. [PMID: 38615717 DOI: 10.1016/j.peptides.2024.171219] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 04/09/2024] [Accepted: 04/10/2024] [Indexed: 04/16/2024]
Abstract
People with obesity and type 2 diabetes have a high prevalence of metabolic-associated steatotic liver disease, hyperlipidemia and cardiovascular disease. Glucagon increases hepatic glucose production; it also decreases hepatic fat accumulation, improves lipidemia and increases energy expenditure. Pharmaceutical strategies to antagonize the glucagon receptor improve glycemic outcomes in people with diabetes and obesity, but they increase hepatic steatosis and worsen dyslipidemia. Co-agonism of the glucagon and glucagon-like peptide-1 (GLP-1) receptors has emerged as a promising strategy to improve glycemia in people with diabetes and obesity. Addition of glucagon receptor agonism enhances weight loss, reduces liver fat and ameliorates dyslipidemia. Prior to clinical use, however, further studies are needed to investigate the safety and efficacy of glucagon and GLP-1 receptor co-agonists in people with diabetes and obesity and related conditions, with specific concerns regarding a higher prevalence of gastrointestinal side effects, loss of muscle mass and increases in heart rate. Furthermore, co-agonists with differing ratios of glucagon:GLP-1 receptor activity vary in their clinical effect; the optimum balance is yet to be identified.
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Affiliation(s)
- Emma Rose McGlone
- Department of Surgery and Cancer, Imperial College London, London, UK; Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Tricia M-M Tan
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK.
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Winther-Sørensen M, Garcia SL, Bartholdy A, Ottenheijm ME, Banasik K, Brunak S, Sørensen CM, Gluud LL, Knop FK, Holst JJ, Rosenkilde MM, Jensen MK, Wewer Albrechtsen NJ. Determinants of plasma levels of proglucagon and the metabolic impact of glucagon receptor signalling: a UK Biobank study. Diabetologia 2024:10.1007/s00125-024-06160-1. [PMID: 38705923 DOI: 10.1007/s00125-024-06160-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/13/2023] [Accepted: 03/13/2024] [Indexed: 05/07/2024]
Abstract
AIMS/HYPOTHESES Glucagon and glucagon-like peptide-1 (GLP-1) are derived from the same precursor; proglucagon, and dual agonists of their receptors are currently being explored for the treatment of obesity and metabolic dysfunction-associated steatotic liver disease (MASLD). Elevated levels of endogenous glucagon (hyperglucagonaemia) have been linked with hyperglycaemia in individuals with type 2 diabetes but are also observed in individuals with obesity and MASLD. GLP-1 levels have been reported to be largely unaffected or even reduced in similar conditions. We investigated potential determinants of plasma proglucagon and associations of glucagon receptor signalling with metabolic diseases based on data from the UK Biobank. METHODS We used exome sequencing data from the UK Biobank for ~410,000 white participants to identify glucagon receptor variants and grouped them based on their known or predicted signalling. Data on plasma levels of proglucagon estimated using Olink technology were available for a subset of the cohort (~40,000). We determined associations of glucagon receptor variants and proglucagon with BMI, type 2 diabetes and liver fat (quantified by liver MRI) and performed survival analyses to investigate if elevated proglucagon predicts type 2 diabetes development. RESULTS Obesity, MASLD and type 2 diabetes were associated with elevated plasma levels of proglucagon independently of each other. Baseline proglucagon levels were associated with the risk of type 2 diabetes development over a 14 year follow-up period (HR 1.13; 95% CI 1.09, 1.17; n=1562; p=1.3×10-12). This association was of the same magnitude across strata of BMI. Carriers of glucagon receptor variants with reduced cAMP signalling had elevated levels of proglucagon (β 0.847; 95% CI 0.04, 1.66; n=17; p=0.04), and carriers of variants with a predicted frameshift mutation had higher levels of liver fat compared with the wild-type reference group (β 0.504; 95% CI 0.03, 0.98; n=11; p=0.04). CONCLUSIONS/INTERPRETATION Our findings support the suggestion that glucagon receptor signalling is involved in MASLD, that plasma levels of proglucagon are linked to the risk of type 2 diabetes development, and that proglucagon levels are influenced by genetic variation in the glucagon receptor, obesity, type 2 diabetes and MASLD. Determining the molecular signalling pathways downstream of glucagon receptor activation may guide the development of biased GLP-1/glucagon co-agonist with improved metabolic benefits. DATA AVAILABILITY All coding is available through https://github.com/nicwin98/UK-Biobank-GCG.
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Affiliation(s)
- Marie Winther-Sørensen
- Department for Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg and Frederiksberg, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sara L Garcia
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Andreas Bartholdy
- Section of Epidemiology, Department of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Maud E Ottenheijm
- Department for Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg and Frederiksberg, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Karina Banasik
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Søren Brunak
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Charlotte M Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Lise Lotte Gluud
- Gastro Unit, Copenhagen University Hospital - Hvidovre, Hvidovre, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Filip K Knop
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, Herlev, Denmark
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Majken K Jensen
- Section of Epidemiology, Department of Public Health, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department for Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg and Frederiksberg, University of Copenhagen, Copenhagen, Denmark.
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
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Scoditti E, Sabatini S, Carli F, Gastaldelli A. Hepatic glucose metabolism in the steatotic liver. Nat Rev Gastroenterol Hepatol 2024; 21:319-334. [PMID: 38308003 DOI: 10.1038/s41575-023-00888-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 12/13/2023] [Indexed: 02/04/2024]
Abstract
The liver is central in regulating glucose homeostasis, being the major contributor to endogenous glucose production and the greatest reserve of glucose as glycogen. It is both a target and regulator of the action of glucoregulatory hormones. Hepatic metabolic functions are altered in and contribute to the highly prevalent steatotic liver disease (SLD), including metabolic dysfunction-associated SLD (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH). In this Review, we describe the dysregulation of hepatic glucose metabolism in MASLD and MASH and associated metabolic comorbidities, and how advances in techniques and models for the assessment of hepatic glucose fluxes in vivo have led to the identification of the mechanisms related to the alterations in glucose metabolism in MASLD and comorbidities. These fluxes can ultimately increase hepatic glucose production concomitantly with fat accumulation and alterations in the secretion and action of glucoregulatory hormones. No pharmacological treatment has yet been approved for MASLD or MASH, but some antihyperglycaemic drugs approved for treating type 2 diabetes have shown positive effects on hepatic glucose metabolism and hepatosteatosis. A deep understanding of how MASLD affects glucose metabolic fluxes and glucoregulatory hormones might assist in the early identification of at-risk individuals and the use or development of targeted therapies.
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Affiliation(s)
- Egeria Scoditti
- Institute of Clinical Physiology, National Research Council, Lecce, Italy
| | - Silvia Sabatini
- Institute of Clinical Physiology, National Research Council, Pisa, Italy
| | - Fabrizia Carli
- Institute of Clinical Physiology, National Research Council, Pisa, Italy
| | - Amalia Gastaldelli
- Institute of Clinical Physiology, National Research Council, Pisa, Italy.
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Chang L, Ma X, Yuan M, Ding L, Gu Y, Liu L, Li Y, Shu H, Liu M, He Q. Lowest Glucagon/Highest C-Peptide in Oral Glucose Tolerance Test: Clinical Utility in Monitoring Glucose Control in Type 2 Diabetes Mellitus. Diabetes Metab Syndr Obes 2024; 17:1769-1780. [PMID: 38645659 PMCID: PMC11032662 DOI: 10.2147/dmso.s459392] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2024] [Accepted: 04/10/2024] [Indexed: 04/23/2024] Open
Abstract
Purpose Understanding factors that influence blood glucose levels in patients with type 2 diabetes mellitus (T2DM) is crucial for managing hyperglycemia. Currently, there is no standardized interpretation method for glucagon levels in oral glucose tolerance test (OGTT). This study aims to assess the relationship between the lowest glucagon/highest C-peptide ratio (Lglc/Hcp) in OGTT and glucose control levels in T2DM. Patients and Methods Clinical data from 120 patients with T2DM were examined to compare the correlations of Lglc/Hcp and other pancreatic islet function-associated indices with fasting blood glucose (G0), glucose at 120 minutes in OGTT (G120), hemoglobin A1c (HbA1c), and the area under the glucose curve in OGTT (AUCglu). Additionally, the study investigated difference in Lglc/Hcp between patient groups based on the highest blood glucose levels (Hglu) in OGTT (Hglu ≥ 16.7 mmol/L vs Hglu < 16.7 mmol/L). Results The generalized linear model suggested that Lglc/Hcp significantly correlated with G0 (B = 0.85, P < 0.001), G120(B = 1.46, P < 0.001), HbA1c (B = 0.67, P < 0.001), and AUCglu (B = 3.46, P < 0.001). This correlation surpassed C-peptide and glucagon-related parameters, even after adjusting for confounding factors. Furthermore, Lglc/Hcp was notably higher in patients with Hglu ≥ 16.7 mmol/L compared to those with Hglu < 16.7 mmol/L (Z = -3.71, p < 0.001). Conclusion Lglc/Hcp in OGTT closely relates to blood glucose control in patients with T2DM, potentially reflecting the overall pancreatic islet function in regulating glucose levels. Moreover, inhibiting glucagon secretion may be a crucial consideration for patients requiring insulin treatment.
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Affiliation(s)
- Lina Chang
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, People’s Republic of China
| | - Xiaohui Ma
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, People’s Republic of China
| | - Menghua Yuan
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, People’s Republic of China
| | - Li Ding
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, People’s Republic of China
| | - Yian Gu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, People’s Republic of China
| | - Lili Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, People’s Republic of China
| | - Yan Li
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, People’s Republic of China
| | - Hua Shu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, People’s Republic of China
| | - Ming Liu
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, People’s Republic of China
| | - Qing He
- Department of Endocrinology and Metabolism, Tianjin Medical University General Hospital, Tianjin, People’s Republic of China
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Suppli MP, Høgedal A, Bagger JI, Chabanova E, van Hall G, Forman JL, Christensen MB, Albrechtsen NJW, Holst JJ, Knop FK. Signs of Glucagon Resistance After a 2-Week Hypercaloric Diet Intervention. J Clin Endocrinol Metab 2024; 109:955-967. [PMID: 37967235 DOI: 10.1210/clinem/dgad666] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/21/2023] [Revised: 11/06/2023] [Accepted: 11/13/2023] [Indexed: 11/17/2023]
Abstract
CONTEXT Hyperglucagonemia is observed in individuals with obesity and contributes to the hyperglycemia of patients with type 2 diabetes. Hyperglucagonemia may develop due to steatosis-induced hepatic glucagon resistance resulting in impaired hepatic amino acid turnover and ensuing elevations of circulating glucagonotropic amino acids. OBJECTIVE We evaluated whether glucagon resistance could be induced in healthy individuals by a hypercaloric diet intervention designed to increase hepatic fat content. METHODS We recruited 20 healthy male individuals to follow a hypercaloric diet and a sedentary lifestyle for 2 weeks. Amino acid concentrations in response to infusion of glucagon were assessed during a pancreatic clamp with somatostatin and basal insulin. The reversibility of any metabolic changes was assessed 8 weeks after the intervention. Hepatic steatosis was assessed by magnetic resonance spectroscopy. RESULTS The intervention led to increased hepatic fat content (382% [206%; 705%], P < .01). Glucagon infusion led to a decrease in the concentration of total amino acids on all experimental days, but the percentage change in total amino acids was reduced (-2.5% ± 0.5% vs -0.2% ± 0.7%, P = .015) and the average slope of the decline in the total amino acid concentration was less steep (-2.0 ± 1.2 vs -1.2 ± 0.3 μM/min, P = .016) after the intervention compared to baseline. The changes were normalized at follow-up. CONCLUSION Our results indicate that short-term unhealthy behavior, which increases hepatic fat content, causes a reversible resistance to the effect of glucagon on amino acid concentrations in healthy individuals, which may explain the hyperglucagonemia associated with obesity and diabetes.
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Affiliation(s)
- Malte Palm Suppli
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, DK-2900 Hellerup, Denmark
| | - Astrid Høgedal
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, DK-2900 Hellerup, Denmark
| | - Jonatan Ising Bagger
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, DK-2900 Hellerup, Denmark
- Steno Diabetes Center Copenhagen, DK-2730 Herlev, Denmark
| | - Elizaveta Chabanova
- Department of Radiology, Herlev Hospital, University of Copenhagen, DK-2730 Herlev, Denmark
| | - Gerrit van Hall
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Clinical Metabolomics Core Facility, Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, DK-2100 Copenhagen, Denmark
| | - Julie Lyng Forman
- Section of Biostatistics, Department of Public Health, University of Copenhagen, DK-1353 Copenhagen, Denmark
| | - Mikkel Bring Christensen
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, DK-2900 Hellerup, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Department of Clinical Pharmacology, Bispebjerg Hospital, University of Copenhagen, DK-2400 Copenhagen, Denmark
- Copenhagen Center for Translational Research, Bispebjerg Hospital, University of Copenhagen, DK-2400 Copenhagen, Denmark
| | - Nicolai Jacob Wewer Albrechtsen
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Department of Clinical Biochemistry, Bispebjerg and Frederiksberg Hospital, University of Copenhagen, DK-2400 Copenhagen, Denmark
| | - Jens Juul Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Filip Krag Knop
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, DK-2900 Hellerup, Denmark
- Steno Diabetes Center Copenhagen, DK-2730 Herlev, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
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Estes SK, Shiota C, O'Brien TP, Printz RL, Shiota M. The impact of glucagon to support postabsorptive glucose flux and glycemia in healthy rats and its attenuation in male Zucker diabetic fatty rats. Am J Physiol Endocrinol Metab 2024; 326:E308-E325. [PMID: 38265288 PMCID: PMC11193518 DOI: 10.1152/ajpendo.00192.2023] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2023] [Revised: 01/19/2024] [Accepted: 01/19/2024] [Indexed: 01/25/2024]
Abstract
Hyperglucagonemia is a hallmark of type 2 diabetes (T2DM), yet the role of elevated plasma glucagon (P-GCG) to promote excessive postabsorptive glucose production and contribute to hyperglycemia in patients with this disease remains debatable. We investigated the acute action of P-GCG to safeguard/support postabsorptive endogenous glucose production (EGP) and euglycemia in healthy Zucker control lean (ZCL) rats. Using male Zucker diabetic fatty (ZDF) rats that exhibit the typical metabolic disorders of human T2DM, such as excessive EGP, hyperglycemia, hyperinsulinemia, and hyperglucagonemia, we examined the ability of hyperglucagonemia to promote greater rates of postabsorptive EGP and hyperglycemia. Euglycemic or hyperglycemic basal insulin (INS-BC) and glucagon (GCG-BC) clamps were performed in the absence or during an acute setting of glucagon deficiency (GCG-DF, ∼10% of basal), either alone or in combination with insulin deficiency (INS-DF, ∼10% of basal). Glucose appearance, disappearance, and cycling rates were measured using [2-3H] and [3-3H]-glucose. In ZCL rats, GCG-DF reduced the levels of hepatic cyclic AMP, EGP, and plasma glucose (PG) by 50%, 32%, and 50%, respectively. EGP fell in the presence GCG-DF and INS-BC, but under GCG-DF and INS-DF, EGP and PG increased two- and threefold, respectively. GCG-DF revealed the hyperglucagonemia present in ZDF rats lacked the ability to regulate hepatic intracellular cyclic AMP levels and glucose flux, since EGP and PG levels fell by only 10%. We conclude that the liver in T2DM suffers from resistance to all three major regulatory factors, glucagon, insulin, and glucose, thus leading to a loss of metabolic flexibility.NEW & NOTEWORTHY In postabsorptive state, basal plasma insulin (P-INS) and plasma glucose (PG) act dominantly to increase hepatic glucose cycling and reduce endogenous glucose production (EGP) and PG in healthy rats, which is only counteracted by the acute action of basal plasma glucagon (P-GCG) to support EGP and euglycemia. Hyperglucagonemia, a hallmark of type 2 diabetes (T2DM) present in Zucker diabetic fatty (ZDF) rats, is not the primary mediator of hyperglycemia and high EGP as commonly thought; instead, the liver is resistant to glucagon as well as insulin and glucose.
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Affiliation(s)
- Shanea K Estes
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Chiyo Shiota
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Tracy P O'Brien
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Richard L Printz
- Department of Medicine, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
| | - Masakazu Shiota
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee, United States
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Zhao J, Zeng J, Zhu C, Li X, Liu D, Zhang J, Li F, Targher G, Fan JG. Genetically predicted plasma levels of amino acids and metabolic dysfunction-associated fatty liver disease risk: a Mendelian randomization study. BMC Med 2023; 21:469. [PMID: 38017422 PMCID: PMC10685523 DOI: 10.1186/s12916-023-03185-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2023] [Accepted: 11/21/2023] [Indexed: 11/30/2023] Open
Abstract
BACKGROUND Emerging metabolomics-based studies suggested links between amino acid metabolism and metabolic dysfunction-associated fatty liver disease (MAFLD) risk; however, whether there exists an aetiological role of amino acid metabolism in MAFLD development remains unknown. The aim of the present study was to assess the causal relationship between circulating levels of amino acids and MAFLD risk. METHODS We conducted a two-sample Mendelian randomization (MR) analysis using summary-level data from genome-wide association studies (GWAS) to evaluate the causal relationship between genetically predicted circulating levels of amino acids and the risk of MAFLD. In the discovery MR analysis, we used data from the largest MAFLD GWAS (8434 cases and 770,180 controls), while in the replication MR analysis, we used data from a GWAS on MAFLD (1483 cases and 17,781 controls) where MAFLD cases were diagnosed using liver biopsy. We used Wald ratios or inverse variance-weighted (IVW) methods in the MR main analysis and weighted median and MR-Egger regression analyses in sensitivity analyses. Furthermore, we performed a conservative MR analysis by restricting genetic instruments to those directly involved in amino acid metabolism pathways. RESULTS We found that genetically predicted higher alanine (OR = 1.43, 95% CI 1.13-1.81) and lower glutamine (OR = 0.83, 95% CI 0.73-0.96) levels were associated with a higher risk of developing MAFLD based on the results from the MR main and conservative analysis. The results from MR sensitivity analyses and complementary analysis using liver proton density fat fraction as a continuous outcome proxying for MAFLD supported the main findings. CONCLUSIONS Novel causal metabolites related to MAFLD development were uncovered through MR analysis, suggesting future potential for evaluating these metabolites as targets for MAFLD prevention or treatment.
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Affiliation(s)
- Jian Zhao
- The Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, No. 1665, Kongjiang Road, Yangpu District, Shanghai, 200092, China.
- Department of Maternal and Child Health, School of Public Health, Shanghai Jiao Tong University, Shanghai, China.
- MRC Integrative Epidemiology Unit, University of Bristol, Bristol, UK.
| | - Jing Zeng
- Department of Gastroenterology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, No. 1665, Kongjiang Road, Yangpu District, Shanghai, 200092, China
| | - Cairong Zhu
- Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
| | - Xuechao Li
- Department of Epidemiology and Biostatistics, West China School of Public Health and West China Fourth Hospital, Sichuan University, Chengdu, China
| | - Dong Liu
- The Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, No. 1665, Kongjiang Road, Yangpu District, Shanghai, 200092, China
| | - Jun Zhang
- The Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, No. 1665, Kongjiang Road, Yangpu District, Shanghai, 200092, China
- Department of Maternal and Child Health, School of Public Health, Shanghai Jiao Tong University, Shanghai, China
| | - Fei Li
- The Ministry of Education and Shanghai Key Laboratory of Children's Environmental Health, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, No. 1665, Kongjiang Road, Yangpu District, Shanghai, 200092, China
- Department of Maternal and Child Health, School of Public Health, Shanghai Jiao Tong University, Shanghai, China
- Department of Developmental and Behavioral Pediatric & Child Primary Care, Brain and Behavioral Research Unit of Shanghai Institute for Pediatric Research, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China
| | - Giovanni Targher
- Department of Medicine, University of Verona, Verona, Italy
- Metabolic Diseases Research Unit, IRCCS Ospedale Sacro Cuore - Don Calabria, Negrar di Valpolicella, Italy
| | - Jian-Gao Fan
- Department of Gastroenterology, Xinhua Hospital, Shanghai Jiao Tong University School of Medicine, No. 1665, Kongjiang Road, Yangpu District, Shanghai, 200092, China.
- Shanghai Key Lab of Pediatric Gastroenterology and Nutrition, Shanghai, China.
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9
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Huang W, Xie C, Wewer Albrechtsen NJ, Sang M, Sun Z, Jones KL, Horowitz M, Rayner CK, Wu T. Serum alanine transaminase is predictive of fasting and postprandial insulin and glucagon concentrations in type 2 diabetes. Peptides 2023; 169:171092. [PMID: 37673303 DOI: 10.1016/j.peptides.2023.171092] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2023] [Revised: 08/05/2023] [Accepted: 08/29/2023] [Indexed: 09/08/2023]
Abstract
The liver plays a key role in glucose homeostasis. Serum liver enzyme levels, including alanine transaminase (ALT), aspartate transaminase (AST) and gamma-glutamyl transferase (GGT), are reportedly predictive of the risk of type 2 diabetes (T2D). However, the link between the liver enzyme profile and metabolic derangements in T2D, particularly the secretion of both insulin and glucagon, is not clear. This study evaluated its relationships with glycemia, insulin and glucagon both during fasting and after an oral glucose load or a mixed meal in T2D. 15 healthy and 43 T2D subjects ingested a 75 g glucose drink. 86 T2D subjects consumed a mixed meal. Venous blood was sampled for measurements of blood glucose and plasma insulin, C-peptide and glucagon. Blood glucose, plasma insulin, C-peptide and glucagon concentrations, both fasting and after oral glucose, correlated directly with ALT, while fewer and weaker correlations were observed with GGT or AST. Subgroup analysis in T2D subjects ascertained that plasma insulin, C-peptide and glucagon concentrations after oral glucose were higher with increasing ALT. Similar findings were observed in the T2D subjects who received a mixed meal. In conclusion, serum liver enzyme profile, particularly ALT, reflects dysregulated fasting and nutrient-stimulated plasma insulin and glucagon concentrations in T2D.
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Affiliation(s)
- Weikun Huang
- Centre for Research Excellence in Translating Nutritional Sciences to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide 5000, Australia
| | - Cong Xie
- Centre for Research Excellence in Translating Nutritional Sciences to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide 5000, Australia
| | | | - Miaomiao Sang
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, School of Medicine, Southeast University, Nanjing 210009, China
| | - Zilin Sun
- Department of Endocrinology, Zhongda Hospital, Institute of Diabetes, School of Medicine, Southeast University, Nanjing 210009, China
| | - Karen L Jones
- Centre for Research Excellence in Translating Nutritional Sciences to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide 5000, Australia; Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide 5000, Australia
| | - Michael Horowitz
- Centre for Research Excellence in Translating Nutritional Sciences to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide 5000, Australia; Endocrine and Metabolic Unit, Royal Adelaide Hospital, Adelaide 5000, Australia
| | - Christopher K Rayner
- Centre for Research Excellence in Translating Nutritional Sciences to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide 5000, Australia; Department of Gastroenterology and Hepatology, Royal Adelaide Hospital, Adelaide, Australia
| | - Tongzhi Wu
- Centre for Research Excellence in Translating Nutritional Sciences to Good Health, Adelaide Medical School, The University of Adelaide, Adelaide 5000, Australia.
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10
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Kjeldsen SAS, Thomsen MN, Skytte MJ, Samkani A, Richter MM, Frystyk J, Magkos F, Hansen E, Thomsen HS, Holst JJ, Madsbad S, Haugaard SB, Krarup T, Wewer Albrechtsen NJ. Markers of Glucagon Resistance Improve With Reductions in Hepatic Steatosis and Body Weight in Type 2 Diabetes. J Endocr Soc 2023; 7:bvad122. [PMID: 37818402 PMCID: PMC10561012 DOI: 10.1210/jendso/bvad122] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/24/2023] [Indexed: 10/12/2023] Open
Abstract
Context Hyperglucagonemia may develop in type 2 diabetes due to obesity-prone hepatic steatosis (glucagon resistance). Markers of glucagon resistance (including the glucagon-alanine index) improve following diet-induced weight loss, but the partial contribution of lowering hepatic steatosis vs body weight is unknown. Objective This work aimed to investigate the dependency of body weight loss following a reduction in hepatic steatosis on markers of glucagon resistance in type 2 diabetes. Methods A post hoc analysis was conducted from 2 previously published randomized controlled trials. We investigated the effect of weight maintenance (study 1: isocaloric feeding) or weight loss (study 2: hypocaloric feeding), both of which induced reductions in hepatic steatosis, on markers of glucagon sensitivity, including the glucagon-alanine index measured using a validated enzyme-linked immunosorbent assay and metabolomics in 94 individuals (n = 28 in study 1; n = 66 in study 2). Individuals with overweight or obesity with type 2 diabetes were randomly assigned to a 6-week conventional diabetes (CD) or carbohydrate-reduced high-protein (CRHP) diet within both isocaloric and hypocaloric feeding-interventions. Results By design, weight loss was greater after hypocaloric compared to isocaloric feeding, but both diets caused similar reductions in hepatic steatosis, allowing us to investigate the effect of reducing hepatic steatosis with or without a clinically relevant weight loss on markers of glucagon resistance. The glucagon-alanine index improved following hypocaloric, but not isocaloric, feeding, independently of macronutrient composition. Conclusion Improvements in glucagon resistance may depend on body weight loss in patients with type 2 diabetes.
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Affiliation(s)
- Sasha A S Kjeldsen
- Department of Clinical Biochemistry, Copenhagen University Hospital-Bispebjerg and Frederiksberg, Copenhagen, 2400, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Mads N Thomsen
- Department of Endocrinology, Copenhagen University Hospital-Bispebjerg and Frederiksberg, Copenhagen, 2400, Denmark
| | - Mads J Skytte
- Department of Endocrinology, Copenhagen University Hospital-Bispebjerg and Frederiksberg, Copenhagen, 2400, Denmark
| | - Amirsalar Samkani
- Department of Endocrinology, Copenhagen University Hospital-Bispebjerg and Frederiksberg, Copenhagen, 2400, Denmark
| | - Michael M Richter
- Department of Clinical Biochemistry, Copenhagen University Hospital-Bispebjerg and Frederiksberg, Copenhagen, 2400, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Jan Frystyk
- Department of Endocrinology, Odense University Hospital, Odense, 5000, Denmark
| | - Faidon Magkos
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg, 1958, Denmark
| | - Elizaveta Hansen
- Department of Radiology, Copenhagen University Hospital-Herlev, Herlev, 2730, Denmark
| | - Henrik S Thomsen
- Department of Radiology, Copenhagen University Hospital-Herlev, Herlev, 2730, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Sten Madsbad
- Department of Endocrinology, Copenhagen University Hospital-Hvidovre, Hvidovre, 2650, Denmark
| | - Steen B Haugaard
- Department of Endocrinology, Copenhagen University Hospital-Bispebjerg and Frederiksberg, Copenhagen, 2400, Denmark
- Institute of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Thure Krarup
- Department of Endocrinology, Copenhagen University Hospital-Bispebjerg and Frederiksberg, Copenhagen, 2400, Denmark
- Department of Nutrition, Exercise and Sports, University of Copenhagen, Frederiksberg, 1958, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department of Clinical Biochemistry, Copenhagen University Hospital-Bispebjerg and Frederiksberg, Copenhagen, 2400, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
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11
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Riahi Y, Kogot-Levin A, Kadosh L, Agranovich B, Malka A, Assa M, Piran R, Avrahami D, Glaser B, Gottlieb E, Jackson F, Cerasi E, Bernal-Mizrachi E, Helman A, Leibowitz G. Hyperglucagonaemia in diabetes: altered amino acid metabolism triggers mTORC1 activation, which drives glucagon production. Diabetologia 2023; 66:1925-1942. [PMID: 37480416 DOI: 10.1007/s00125-023-05967-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 06/07/2023] [Indexed: 07/24/2023]
Abstract
AIM/HYPOTHESIS Hyperglycaemia is associated with alpha cell dysfunction, leading to dysregulated glucagon secretion in type 1 and type 2 diabetes; however, the mechanisms involved are still elusive. The nutrient sensor mammalian target of rapamycin complex 1 (mTORC1) plays a major role in the maintenance of alpha cell mass and function. We studied the regulation of alpha cell mTORC1 by nutrients and its role in the development of hyperglucagonaemia in diabetes. METHODS Alpha cell mTORC1 activity was assessed by immunostaining for phosphorylation of its downstream target, the ribosomal protein S6, and glucagon, followed by confocal microscopy on pancreatic sections and flow cytometry on dispersed human and mouse islets and the alpha cell line, αTC1-6. Metabolomics and metabolic flux were studied by 13C glucose labelling in 2.8 or 16.7 mmol/l glucose followed by LC-MS analysis. To study the role of mTORC1 in mediating hyperglucagonaemia in diabetes, we generated an inducible alpha cell-specific Rptor knockout in the Akita mouse model of diabetes and tested the effects on glucose tolerance by IPGTT and on glucagon secretion. RESULTS mTORC1 activity was increased in alpha cells from diabetic Akita mice in parallel to the development of hyperglycaemia and hyperglucagonaemia (two- to eightfold increase). Acute exposure of mouse and human islets to amino acids stimulated alpha cell mTORC1 (3.5-fold increase), whereas high glucose concentrations inhibited mTORC1 (1.4-fold decrease). The mTORC1 response to glucose was abolished in human and mouse diabetic alpha cells following prolonged islet exposure to high glucose levels, resulting in sustained activation of mTORC1, along with increased glucagon secretion. Metabolomics and metabolic flux analysis showed that exposure to high glucose levels enhanced glycolysis, glucose oxidation and the synthesis of glucose-derived amino acids. In addition, chronic exposure to high glucose levels increased the expression of Slc7a2 and Slc38a4, which encode amino acid transporters, as well as the levels of branched-chain amino acids and methionine cycle metabolites (~1.3-fold increase for both). Finally, conditional Rptor knockout in alpha cells from adult diabetic mice inhibited mTORC1, thereby inhibiting glucagon secretion (~sixfold decrease) and improving diabetes, despite persistent insulin deficiency. CONCLUSIONS/INTERPRETATION Alpha cell exposure to hyperglycaemia enhances amino acid synthesis and transport, resulting in sustained activation of mTORC1, thereby increasing glucagon secretion. mTORC1 therefore plays a major role in mediating alpha cell dysfunction in diabetes. DATA AVAILABILITY All sequencing data are available from the Gene Expression Omnibus (GEO) repository (accession no. GSE154126; https://www.ncbi.nlm.nih.gov/geo/query/acc.cgi?acc=GSE154126 ).
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Affiliation(s)
- Yael Riahi
- Diabetes Unit, Department of Endocrinology and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Aviram Kogot-Levin
- Diabetes Unit, Department of Endocrinology and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Liat Kadosh
- Diabetes Unit, Department of Endocrinology and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Bella Agranovich
- Laboratory for Metabolism in Health and Disease, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
| | - Assaf Malka
- The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Michael Assa
- The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Ron Piran
- The Azrieli Faculty of Medicine, Bar-Ilan University, Safed, Israel
| | - Dana Avrahami
- Diabetes Unit, Department of Endocrinology and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
- Department of Developmental Biology and Cancer Research, Hadassah Medical Center, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Benjamin Glaser
- Diabetes Unit, Department of Endocrinology and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Eyal Gottlieb
- Laboratory for Metabolism in Health and Disease, Ruth and Bruce Rappaport Faculty of Medicine, Technion-Israel Institute of Technology, Haifa, Israel
- Department of Cancer Biology, University of Texas MD Anderson Cancer Center, Houston, TX, USA
| | - Fields Jackson
- Department of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel
| | - Erol Cerasi
- Diabetes Unit, Department of Endocrinology and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ernesto Bernal-Mizrachi
- Department of Internal Medicine, Division of Endocrinology, Diabetes and Metabolism, Miller School of Medicine, University of Miami, Miami, FL, USA
| | - Aharon Helman
- Department of Biochemistry, Food Science and Nutrition, Robert H. Smith Faculty of Agriculture, Food and Environment, Hebrew University of Jerusalem, Rehovot, Israel.
| | - Gil Leibowitz
- Diabetes Unit, Department of Endocrinology and Metabolism, Faculty of Medicine, Hebrew University of Jerusalem, Jerusalem, Israel.
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12
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Zhang J, Zheng Y, Martens L, Pfeiffer AFH. The Regulation and Secretion of Glucagon in Response to Nutrient Composition: Unraveling Their Intricate Mechanisms. Nutrients 2023; 15:3913. [PMID: 37764697 PMCID: PMC10536047 DOI: 10.3390/nu15183913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/31/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Glucagon was initially regarded as a hyperglycemic substance; however, recent research has revealed its broader role in metabolism, encompassing effects on glucose, amino acids (AAs), and lipid metabolism. Notably, the interplay of glucagon with nutrient intake, particularly of AAs, and non-nutrient components is central to its secretion. Fasting and postprandial hyperglucagonemia have long been linked to the development and progression of type 2 diabetes (T2DM). However, recent studies have brought to light the positive impact of glucagon agonists on lipid metabolism and energy homeostasis. This review explores the multifaceted actions of glucagon, focusing on its regulation, signaling pathways, and effects on glucose, AAs, and lipid metabolism. The interplay between glucagon and other hormones, including insulin and incretins, is examined to provide a mechanistic understanding of its functions. Notably, the liver-α-cell axis, which involves glucagon and amino acids, emerges as a critical aspect of metabolic regulation. The dysregulation of glucagon secretion and its impact on conditions such as T2DM are discussed. The review highlights the potential therapeutic applications of targeting the glucagon pathway in the treatment of metabolic disorders.
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Affiliation(s)
- Jiudan Zhang
- The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou 310053, China;
- Department of Endocrinology, Diabetes and Nutrition, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (L.M.); (A.F.H.P.)
| | - Yang Zheng
- The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou 310053, China;
| | - Lisa Martens
- Department of Endocrinology, Diabetes and Nutrition, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (L.M.); (A.F.H.P.)
- Nutritional Science, University of Potsdam, 14469 Potsdam, Germany
| | - Andreas F. H. Pfeiffer
- Department of Endocrinology, Diabetes and Nutrition, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (L.M.); (A.F.H.P.)
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13
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Wewer Albrechtsen NJ, Holst JJ, Cherrington AD, Finan B, Gluud LL, Dean ED, Campbell JE, Bloom SR, Tan TMM, Knop FK, Müller TD. 100 years of glucagon and 100 more. Diabetologia 2023; 66:1378-1394. [PMID: 37367959 DOI: 10.1007/s00125-023-05947-y] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2023] [Accepted: 04/18/2023] [Indexed: 06/28/2023]
Abstract
The peptide hormone glucagon, discovered in late 1922, is secreted from pancreatic alpha cells and is an essential regulator of metabolic homeostasis. This review summarises experiences since the discovery of glucagon regarding basic and clinical aspects of this hormone and speculations on the future directions for glucagon biology and glucagon-based therapies. The review was based on the international glucagon conference, entitled 'A hundred years with glucagon and a hundred more', held in Copenhagen, Denmark, in November 2022. The scientific and therapeutic focus of glucagon biology has mainly been related to its role in diabetes. In type 1 diabetes, the glucose-raising properties of glucagon have been leveraged to therapeutically restore hypoglycaemia. The hyperglucagonaemia evident in type 2 diabetes has been proposed to contribute to hyperglycaemia, raising questions regarding underlying mechanism and the importance of this in the pathogenesis of diabetes. Mimicry experiments of glucagon signalling have fuelled the development of several pharmacological compounds including glucagon receptor (GCGR) antagonists, GCGR agonists and, more recently, dual and triple receptor agonists combining glucagon and incretin hormone receptor agonism. From these studies and from earlier observations in extreme cases of either glucagon deficiency or excess secretion, the physiological role of glucagon has expanded to also involve hepatic protein and lipid metabolism. The interplay between the pancreas and the liver, known as the liver-alpha cell axis, reflects the importance of glucagon for glucose, amino acid and lipid metabolism. In individuals with diabetes and fatty liver diseases, glucagon's hepatic actions may be partly impaired resulting in elevated levels of glucagonotropic amino acids, dyslipidaemia and hyperglucagonaemia, reflecting a new, so far largely unexplored pathophysiological phenomenon termed 'glucagon resistance'. Importantly, the hyperglucagonaemia as part of glucagon resistance may result in increased hepatic glucose production and hyperglycaemia. Emerging glucagon-based therapies show a beneficial impact on weight loss and fatty liver diseases and this has sparked a renewed interest in glucagon biology to enable further pharmacological pursuits.
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Affiliation(s)
- Nicolai J Wewer Albrechtsen
- Department of Clinical Biochemistry, Copenhagen University Hospital - Bispebjerg and Frederiksberg Hospital, Copenhagen, Denmark.
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Alan D Cherrington
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
| | - Brian Finan
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA
| | - Lise Lotte Gluud
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Gastro Unit, Copenhagen University Hospital Hvidovre, Hvidovre, Denmark
| | - E Danielle Dean
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN, USA
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN, USA
| | - Jonathan E Campbell
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC, USA
- Department of Medicine, Endocrinology Division, Duke University Medical Center, Durham, NC, USA
- Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC, USA
| | - Stephen R Bloom
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Tricia M-M Tan
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London, UK
| | - Filip K Knop
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- Steno Diabetes Center Copenhagen, Herlev, Denmark
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), München Neuherberg, Germany
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14
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Hamilton A, Eliasson L, Knudsen JG. Amino acids and the changing face of the α-cell. Peptides 2023:171039. [PMID: 37295651 DOI: 10.1016/j.peptides.2023.171039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2023] [Revised: 05/31/2023] [Accepted: 06/05/2023] [Indexed: 06/12/2023]
Abstract
Glucagon has long been defined by its glucogenic action and as a result α-cells have been characterised based largely on their interaction with glucose. Recent findings have challenged this preconception, bringing to the fore the significant role glucagon plays in amino acid breakdown and underlining the importance of amino acids in glucagon secretion. The challenge that remains is defining the mechanism that underlie these effects - understanding which amino acids are most important, how they act on the α-cell and how their actions integrate with other fuels such as glucose and fatty acids. This review will describe the current relationship between amino acids and glucagon and how we can use this knowledge to redefine the α-cell.
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Affiliation(s)
- Alexander Hamilton
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Denmark; Department of Clinical Sciences in Malmö, Islet Cell Exocytosis, Lund University Diabetes Centre, Lund University, Malmö, Sweden.
| | - Lena Eliasson
- Department of Clinical Sciences in Malmö, Islet Cell Exocytosis, Lund University Diabetes Centre, Lund University, Malmö, Sweden.
| | - Jakob G Knudsen
- Section for Cell Biology and Physiology, Department of Biology, University of Copenhagen, Denmark.
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15
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Hoffmann C, Schwarz PE, Mantzoros CS, Birkenfeld AL, Wolfrum C, Solimena M, Bornstein SR, Perakakis N. Circulating levels of gastrointestinal hormones in prediabetes reversing to normoglycemia or progressing to diabetes in a year-A cross-sectional and prospective analysis. Diabetes Res Clin Pract 2023; 199:110636. [PMID: 36940795 DOI: 10.1016/j.diabres.2023.110636] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Revised: 03/01/2023] [Accepted: 03/16/2023] [Indexed: 03/23/2023]
Abstract
AIMS We aimed to compare the concentrations of GLP-1, glucagon and GIP (established regulators of glucose homeostasis) and glicentin (emerging new metabolic marker)during an OGTT in patients with normal glucose tolerance (NGT), prediabetes and diabetes at onset, and one-year before, when all had prediabetes. METHODS GLP-1, glucagon, GIP and glicentin concentrations were measured and compared with markers of body composition, insulin sensitivity and β-cell function at a 5-timepoint OGTT in 125 subjects (30 diabetes, 65 prediabetes, 30 NGT) and in 106 of them one-year before, when all had prediabetes. RESULTS At baseline, when all subjects were in prediabetic state, hormonal levels did not differ between groups. One year later, patients progressing to diabetes had lower postprandial increases of glicentin and GLP-1, lower postprandial decrease of glucagon, and higher levels of fasting GIP compared to patients regressing to NGT. Changes in glicentin and GLP-1 AUC within this year correlated negatively with changes in Glucose AUC of OGTT and with changes in markers of beta cell function. CONCLUSION Incretins, glucagon and glicentin profiles in prediabetic state cannot predict future glycemic traits, but prediabetes progressing to diabetes is accompanied by deterioration of postprandial increases of GLP-1 and glicentin.
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Affiliation(s)
- Carlotta Hoffmann
- Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany
| | - Peter E Schwarz
- Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany; Paul Langerhans Institute Dresden (PLID), Helmholtz Center Munich, University Hospital and Faculty of Medicine, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), IngolstädterLandstrasse 1, 85764 Neuherberg, Germany
| | - Christos S Mantzoros
- Department of Medicine, Boston VA Healthcare System and Beth Israel Deaconess Medical Center, Harvard Medical School, 25 Shattuck St, Boston, MA 02115, USA
| | - Andreas L Birkenfeld
- German Center for Diabetes Research (DZD e.V.), Department of Internal Medicine IV, Department of Endocrinology, Diabetology and Nephrology, University Hospital of Eberhard-Karls-University Tübingen,Geissweg 3, 72076 Tübingen, Germany; Diabetes and Nutritional Sciences, King's College London, Strand, London WC2R 2LS, UK; Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the Eberhard-Karls University of Tübingen, Geissweg 3, 72076 Tübingen, Germany
| | - Christian Wolfrum
- Laboratory of Translational Nutrition Biology, Institute of Food, Nutrition and Health, Department of Health Sciences and Technology, ETH Zürich, Schorenstrasse 16, 8603 Schwerzenbach, Switzerland
| | - Michele Solimena
- Paul Langerhans Institute Dresden (PLID), Helmholtz Center Munich, University Hospital and Faculty of Medicine, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), IngolstädterLandstrasse 1, 85764 Neuherberg, Germany
| | - Stefan R Bornstein
- Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany; Paul Langerhans Institute Dresden (PLID), Helmholtz Center Munich, University Hospital and Faculty of Medicine, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), IngolstädterLandstrasse 1, 85764 Neuherberg, Germany; Diabetes and Nutritional Sciences, King's College London, Strand, London WC2R 2LS, UK
| | - Nikolaos Perakakis
- Department of Internal Medicine III, University Hospital Carl Gustav Carus, Technische Universität Dresden, Fetscherstraße 74, 01307 Dresden, Germany; Paul Langerhans Institute Dresden (PLID), Helmholtz Center Munich, University Hospital and Faculty of Medicine, TU Dresden, Fetscherstraße 74, 01307 Dresden, Germany; German Center for Diabetes Research (DZD e.V.), IngolstädterLandstrasse 1, 85764 Neuherberg, Germany.
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16
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Hædersdal S, Andersen A, Knop FK, Vilsbøll T. Revisiting the role of glucagon in health, diabetes mellitus and other metabolic diseases. Nat Rev Endocrinol 2023; 19:321-335. [PMID: 36932176 DOI: 10.1038/s41574-023-00817-4] [Citation(s) in RCA: 33] [Impact Index Per Article: 33.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 02/17/2023] [Indexed: 03/19/2023]
Abstract
Insulin and glucagon exert opposing effects on glucose metabolism and, consequently, pancreatic islet β-cells and α-cells are considered functional antagonists. The intra-islet hypothesis has previously dominated the understanding of glucagon secretion, stating that insulin acts to inhibit the release of glucagon. By contrast, glucagon is a potent stimulator of insulin secretion and has been used to test β-cell function. Over the past decade, α-cells have received increasing attention due to their ability to stimulate insulin secretion from neighbouring β-cells, and α-cell-β-cell crosstalk has proven central for glucose homeostasis in vivo. Glucagon is not only the counter-regulatory hormone to insulin in glucose metabolism but also glucagon secretion is more susceptible to changes in the plasma concentration of certain amino acids than to changes in plasma concentrations of glucose. Thus, the actions of glucagon also include a central role in amino acid turnover and hepatic fat oxidation. This Review provides insights into glucagon secretion, with a focus on the local paracrine actions on glucagon and the importance of α-cell-β-cell crosstalk. We focus on dysregulated glucagon secretion in obesity, non-alcoholic fatty liver disease and type 2 diabetes mellitus. Lastly, the future potential of targeting hyperglucagonaemia and applying dual and triple receptor agonists with glucagon receptor-activating properties in combination with incretin hormone receptor agonism is discussed.
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Affiliation(s)
- Sofie Hædersdal
- Clinical Research, Copenhagen University Hospital - Steno Diabetes Center Copenhagen, Herlev, Denmark.
- Center for Clinical Metabolic Research, Copenhagen University Hospital - Herlev and Gentofte, Hellerup, Denmark.
| | - Andreas Andersen
- Clinical Research, Copenhagen University Hospital - Steno Diabetes Center Copenhagen, Herlev, Denmark
- Center for Clinical Metabolic Research, Copenhagen University Hospital - Herlev and Gentofte, Hellerup, Denmark
| | - Filip K Knop
- Clinical Research, Copenhagen University Hospital - Steno Diabetes Center Copenhagen, Herlev, Denmark
- Center for Clinical Metabolic Research, Copenhagen University Hospital - Herlev and Gentofte, Hellerup, Denmark
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Tina Vilsbøll
- Clinical Research, Copenhagen University Hospital - Steno Diabetes Center Copenhagen, Herlev, Denmark.
- Center for Clinical Metabolic Research, Copenhagen University Hospital - Herlev and Gentofte, Hellerup, Denmark.
- Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
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17
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Xiao Y, Wang Y, Ryu J, Liu W, Zou H, Zhang R, Yan Y, Dai Z, Zhang D, Sun LZ, Liu F, Zhou Z, Dong LQ. Upregulated TGF-β1 contributes to hyperglycaemia in type 2 diabetes by potentiating glucagon signalling. Diabetologia 2023; 66:1142-1155. [PMID: 36917279 DOI: 10.1007/s00125-023-05889-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/24/2022] [Accepted: 01/12/2023] [Indexed: 03/16/2023]
Abstract
AIMS/HYPOTHESIS Glucagon-stimulated hepatic gluconeogenesis contributes to endogenous glucose production during fasting. Recent studies suggest that TGF-β is able to promote hepatic gluconeogenesis in mice. However, the physiological relevance of serum TGF-β levels to human glucose metabolism and the mechanism by which TGF-β enhances gluconeogenesis remain largely unknown. As enhanced gluconeogenesis is a signature feature of type 2 diabetes, elucidating the molecular mechanisms underlying TGF-β-promoted hepatic gluconeogenesis would allow us to better understand the process of normal glucose production and the pathophysiology of this process in type 2 diabetes. This study aimed to investigate the contribution of upregulated TGF-β1 in human type 2 diabetes and the molecular mechanism underlying the action of TGF-β1 in glucose metabolism. METHODS Serum levels of TGF-β1 were measured by ELISA in 74 control participants with normal glucose tolerance and 75 participants with type 2 diabetes. Human liver tissue was collected from participants without obesity and with or without type 2 diabetes for the measurement of TGF-β1 and glucagon signalling. To investigate the role of Smad3, a key signalling molecule downstream of the TGF-β1 receptor, in mediating the effect of TGF-β1 on glucagon signalling, we generated Smad3 knockout mice. Glucose levels in Smad3 knockout mice were measured during prolonged fasting and a glucagon tolerance test. Mouse primary hepatocytes were isolated from Smad3 knockout and wild-type (WT) mice to investigate the underlying molecular mechanisms. Smad3 phosphorylation was detected by western blotting, levels of cAMP were detected by ELISA and levels of protein kinase A (PKA)/cAMP response element-binding protein (CREB) phosphorylation were detected by western blotting. The dissociation of PKA subunits was measured by immunoprecipitation. RESULTS We observed higher levels of serum TGF-β1 in participants without obesity and with type 2 diabetes than in healthy control participants, which was positively correlated with HbA1c and fasting blood glucose levels. In addition, hyperactivation of the CREB and Smad3 signalling pathways was observed in the liver of participants with type 2 diabetes. Treating WT mouse primary hepatocytes with TGF-β1 greatly potentiated glucagon-stimulated PKA/CREB phosphorylation and hepatic gluconeogenesis. Mechanistically, TGF-β1 treatment induced the binding of Smad3 to the regulatory subunit of PKA (PKA-R), which prevented the association of PKA-R with the catalytic subunit of PKA (PKA-C) and led to the potentiation of glucagon-stimulated PKA signalling and gluconeogenesis. CONCLUSIONS/INTERPRETATION The hepatic TGF-β1/Smad3 pathway sensitises the effect of glucagon/PKA signalling on gluconeogenesis and synergistically promotes hepatic glucose production. Reducing serum levels of TGF-β1 and/or preventing hyperactivation of TGF-β1 signalling could be a novel approach for alleviating hyperglycaemia in type 2 diabetes.
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Affiliation(s)
- Yang Xiao
- National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Yanfei Wang
- National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Department of Endocrinology, The First People's Hospital of Foshan, Foshan, China
| | - Jiyoon Ryu
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Wei Liu
- National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Division of Biliopancreatic Surgery and Bariatric Surgery, Department of General Surgery, The Second Xiangya Hospital of Central South University, Changsha, China
| | - Hailan Zou
- National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Rong Zhang
- National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Yin Yan
- National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Zhe Dai
- Department of Endocrinology, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Deling Zhang
- Department of Pathophysiology, Wuhan University School of Basic Medical Sciences, Wuhan, China
| | - Lu-Zhe Sun
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA
| | - Feng Liu
- National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
- Metabolic Syndrome Research Center, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China
| | - Zhiguang Zhou
- National Clinical Research Center for Metabolic Diseases, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
- Key Laboratory of Diabetes Immunology, Ministry of Education, and Department of Metabolism and Endocrinology, The Second Xiangya Hospital of Central South University, Changsha, Hunan, China.
| | - Lily Q Dong
- Department of Cell Systems and Anatomy, University of Texas Health San Antonio, San Antonio, TX, USA.
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18
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Winther-Sørensen M, Holst JJ, Wewer Albrechtsen NJ. The feedback cycles between glucose, amino acids and lipids and alpha cell secretion and their role in metabolic fatty liver disease. Curr Opin Lipidol 2023; 34:27-31. [PMID: 36373738 DOI: 10.1097/mol.0000000000000857] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
PURPOSE OF REVIEW Glucagon increases hepatic glucose production and in patients with metabolic diseases, glucagon secretion is increased contributing to diabetic hyperglycemia. This review explores the role of amino acids and lipids in the regulation of glucagon secretion and how it may be disturbed in metabolic diseases such as obesity and metabolic associated fatty liver disease (MAFLD). RECENT FINDINGS Human and animal studies have shown that MAFLD is associated with glucagon resistance towards amino acid catabolism, resulting in elevated plasma levels of amino acids. A recent clinical study showed that MAFLD is also associated with glucagon resistance towards lipid metabolism. In contrast, MAFLD may not decrease hepatic sensitivity to the stimulatory effects of glucagon on glucose production. SUMMARY Elevated plasma levels of amino acids and lipids associated with MAFLD may cause diabetogenic hyperglucagonemia. MAFLD and glucagon resistance may therefore be causally linked to hyperglycemia and the development of type 2 diabetes.
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Affiliation(s)
- Marie Winther-Sørensen
- Department of Biomedical Sciences
- NNF Center for Protein Research, Faculty of Health and Medical Sciences
| | | | - Nicolai J Wewer Albrechtsen
- Department of Biomedical Sciences
- NNF Center for Protein Research, Faculty of Health and Medical Sciences
- Department for Clinical Biochemistry, Bispebjerg and Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark
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19
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Pixner T, Stummer N, Schneider AM, Lukas A, Gramlinger K, Julian V, Thivel D, Mörwald K, Mangge H, Dalus C, Aigner E, Furthner D, Weghuber D, Maruszczak K. The relationship between glucose and the liver-alpha cell axis - A systematic review. Front Endocrinol (Lausanne) 2023; 13:1061682. [PMID: 36686477 PMCID: PMC9849557 DOI: 10.3389/fendo.2022.1061682] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/04/2022] [Accepted: 12/13/2022] [Indexed: 01/06/2023] Open
Abstract
Until recently, glucagon was considered a mere antagonist to insulin, protecting the body from hypoglycemia. This notion changed with the discovery of the liver-alpha cell axis (LACA) as a feedback loop. The LACA describes how glucagon secretion and pancreatic alpha cell proliferation are stimulated by circulating amino acids. Glucagon in turn leads to an upregulation of amino acid metabolism and ureagenesis in the liver. Several increasingly common diseases (e.g., non-alcoholic fatty liver disease, type 2 diabetes, obesity) disrupt this feedback loop. It is important for clinicians and researchers alike to understand the liver-alpha cell axis and the metabolic sequelae of these diseases. While most of previous studies have focused on fasting concentrations of glucagon and amino acids, there is limited knowledge of their dynamics after glucose administration. The authors of this systematic review applied PRISMA guidelines and conducted PubMed searches to provide results of 8078 articles (screened and if relevant, studied in full). This systematic review aims to provide better insight into the LACA and its mediators (amino acids and glucagon), focusing on the relationship between glucose and the LACA in adult and pediatric subjects.
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Affiliation(s)
- Thomas Pixner
- Department of Pediatric and Adolescent Medicine, Salzkammergutklinikum Voecklabruck, Voecklabruck, Austria
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
| | - Nathalie Stummer
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Anna Maria Schneider
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Andreas Lukas
- Department of Pediatric and Adolescent Medicine, Salzkammergutklinikum Voecklabruck, Voecklabruck, Austria
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
| | - Karin Gramlinger
- Department of Pediatric and Adolescent Medicine, Salzkammergutklinikum Voecklabruck, Voecklabruck, Austria
| | - Valérie Julian
- Department of Sport Medicine and Functional Explorations, Diet and Musculoskeletal Health Team, Human Nutrition Research Center (CRNH), INRA, University Hospital of Clermont-Ferrand, University of Clermont Auvergne, Clermont-Ferrand, France
| | - David Thivel
- Laboratory of Metabolic Adaptations to Exercise under Physiological and Pathological Conditions (AME2P), University of Clermont Auvergne, Clermont-Ferrand, France
| | - Katharina Mörwald
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Harald Mangge
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
| | - Christopher Dalus
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Elmar Aigner
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- First Department of Medicine, Paracelsus Medical University, Salzburg, Austria
| | - Dieter Furthner
- Department of Pediatric and Adolescent Medicine, Salzkammergutklinikum Voecklabruck, Voecklabruck, Austria
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
| | - Daniel Weghuber
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
| | - Katharina Maruszczak
- Obesity Research Unit, Paracelsus Medical University, Salzburg, Austria
- Department of Pediatrics, Paracelsus Medical University, Salzburg, Austria
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20
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Elmelund E, Galsgaard KD, Johansen CD, Trammell SA, Bomholt AB, Winther-Sørensen M, Hunt JE, Sørensen CM, Kruse T, Lau JF, Grevengoed TJ, Holst JJ, Wewer Albrechtsen NJ. Opposing effects of chronic glucagon receptor agonism and antagonism on amino acids, hepatic gene expression, and alpha cells. iScience 2022; 25:105296. [PMID: 36325048 PMCID: PMC9618771 DOI: 10.1016/j.isci.2022.105296] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/29/2022] [Accepted: 09/30/2022] [Indexed: 01/09/2023] Open
Abstract
The pancreatic hormone, glucagon, is known to regulate hepatic glucose production, but recent studies suggest that its regulation of hepatic amino metabolism is equally important. Here, we show that chronic glucagon receptor activation with a long-acting glucagon analog increases amino acid catabolism and ureagenesis and causes alpha cell hypoplasia in female mice. Conversely, chronic glucagon receptor inhibition with a glucagon receptor antibody decreases amino acid catabolism and ureagenesis and causes alpha cell hyperplasia and beta cell loss. These effects were associated with the transcriptional regulation of hepatic genes related to amino acid uptake and catabolism and by the non-transcriptional modulation of the rate-limiting ureagenesis enzyme, carbamoyl phosphate synthetase-1. Our results support the importance of glucagon receptor signaling for amino acid homeostasis and pancreatic islet integrity in mice and provide knowledge regarding the long-term consequences of chronic glucagon receptor agonism and antagonism. Glucagon receptor agonism increases amino acid catabolism and hepatic CPS-1 activity Glucagon receptor signaling regulates the number of pancreatic alpha cells Glucagon regulates the hepatic transcription of genes involved in amino acid metabolism
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Affiliation(s)
- Emilie Elmelund
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Katrine D. Galsgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Christian D. Johansen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Samuel A.J. Trammell
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Anna B. Bomholt
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Marie Winther-Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Jenna E. Hunt
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Charlotte M. Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Thomas Kruse
- Novo Nordisk A/S, Research Chemistry, Novo Nordisk Park, 2760 Måløv, Denmark
| | - Jesper F. Lau
- Novo Nordisk A/S, Research Chemistry, Novo Nordisk Park, 2760 Måløv, Denmark
| | - Trisha J. Grevengoed
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Jens J. Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Nicolai J. Wewer Albrechtsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Clinical Biochemistry, Bispebjerg & Frederiksberg Hospitals, University of Copenhagen, 2400 Bispebjerg, Denmark
- Corresponding author
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21
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Heebøll S, Risikesan J, Ringgaard S, Kumarathas I, Sandahl TD, Grønbæk H, Søndergaard E, Nielsen S. Impaired Glucagon-Mediated Suppression of VLDL-Triglyceride Secretion in Individuals With Metabolic Dysfunction-Associated Fatty Liver Disease (MAFLD). Diabetes 2022; 71:2402-2411. [PMID: 36001750 PMCID: PMC9630084 DOI: 10.2337/db22-0313] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2022] [Accepted: 08/22/2022] [Indexed: 01/25/2023]
Abstract
Individuals with metabolic dysfunction-associated fatty liver disease (MAFLD) have elevated plasma lipids as well as glucagon, although glucagon suppresses hepatic VLDL-triglyceride (TG) secretion. We hypothesize that the sensitivity to glucagon in hepatic lipid metabolism is impaired in MAFLD. We recruited 11 subjects with severe MAFLD (MAFLD+), 10 with mild MAFLD (MAFLD-), and 7 overweight control (CON) subjects. We performed a pancreatic clamp with a somatostatin analog (octreotide) to suppress endogenous hormone production, combined with infusion of low-dose glucagon (0.65 ng/kg/min, t = 0-270 min, LowGlucagon), followed by high-dose glucagon (1.5 ng/kg/min, t = 270-450 min, HighGlucagon). VLDL-TG and glucose tracers were used to evaluate VLDL-TG kinetics and endogenous glucose production (EGP). HighGlucagon suppressed VLDL-TG secretion compared with LowGlucagon. This suppression was markedly attenuated in MAFLD subjects compared with CON subjects (MAFLD+: 13% ± [SEM] 5%; MAFLD-: 10% ± 3%; CON: 36% ± 7%, P < 0.01), with no difference between MAFLD groups. VLDL-TG concentration and VLDL-TG oxidation rate increased between LowGlucagon and HighGlucagon in MAFLD+ subjects compared with CON subjects. EGP transiently increased during HighGlucagon without any difference between the three groups. Individuals with MAFLD have a reduced sensitivity to glucagon in the hepatic TG metabolism, which could contribute to the dyslipidemia seen in MAFLD patients. ClinicalTrials.gov: NCT04042142.
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Affiliation(s)
- Sara Heebøll
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
- Corresponding author: Sara Heebøll,
| | - Jeyanthini Risikesan
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
- Department of Internal Medicine, Regional Hospital Viborg, Viborg, Denmark
| | - Steffen Ringgaard
- Magnetic Resonance Research Centre, Aarhus University, Aarhus, Denmark
| | - Indumathi Kumarathas
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Thomas D. Sandahl
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Henning Grønbæk
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Esben Søndergaard
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
| | - Søren Nielsen
- Steno Diabetes Center Aarhus, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
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22
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Capozzi ME, D'Alessio DA, Campbell JE. The past, present, and future physiology and pharmacology of glucagon. Cell Metab 2022; 34:1654-1674. [PMID: 36323234 PMCID: PMC9641554 DOI: 10.1016/j.cmet.2022.10.001] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2022] [Revised: 08/23/2022] [Accepted: 09/30/2022] [Indexed: 11/07/2022]
Abstract
The evolution of glucagon has seen the transition from an impurity in the preparation of insulin to the development of glucagon receptor agonists for use in type 1 diabetes. In type 2 diabetes, glucagon receptor antagonists have been explored to reduce glycemia thought to be induced by hyperglucagonemia. However, the catabolic actions of glucagon are currently being leveraged to target the rise in obesity that paralleled that of diabetes, bringing the pharmacology of glucagon full circle. During this evolution, the physiological importance of glucagon advanced beyond the control of hepatic glucose production, incorporating critical roles for glucagon to regulate both lipid and amino acid metabolism. Thus, it is unsurprising that the study of glucagon has left several paradoxes that make it difficult to distill this hormone down to a simplified action. Here, we describe the history of glucagon from the past to the present and suggest some direction to the future of this field.
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Affiliation(s)
- Megan E Capozzi
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA
| | - David A D'Alessio
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA; Department of Medicine, Endocrinology Division, Duke University Medical Center, Durham, NC 27701, USA
| | - Jonathan E Campbell
- Duke Molecular Physiology Institute, Duke University Medical Center, Durham, NC 27701, USA; Department of Medicine, Endocrinology Division, Duke University Medical Center, Durham, NC 27701, USA; Department of Pharmacology and Cancer Biology, Duke University Medical Center, Durham, NC 27701, USA.
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23
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Maruszczak K, Rasmussen C, Ceutz FR, Ørgaard A, Elmelund E, Richter MM, Holst JJ, Winther-Sørensen M, Wewer Albrechtsen NJ. Arginine-induced glucagon secretion and glucagon-induced enhancement of amino acid catabolism are not influenced by ambient glucose levels in mice. Am J Physiol Endocrinol Metab 2022; 323:E207-E214. [PMID: 35830690 DOI: 10.1152/ajpendo.00122.2022] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Amino acids stimulate the secretion of glucagon, and glucagon receptor signaling regulates amino acid catabolism via ureagenesis, together constituting the liver-α cell axis. Impairment of the liver-α cell axis is observed in metabolic diseases such as diabetes. It is, however, unknown whether glucose affects the liver-α cell axis. We investigated the role of glucose on the liver-α cell axis in vivo and ex vivo. The isolated perfused mouse pancreas was used to evaluate the direct effect of low (3.5 mmol/L) and high (15 mmol/L) glucose levels on amino acid (10 mmol/L arginine)-induced glucagon secretion. High glucose levels alone lowered glucagon secretion, but the amino acid-induced glucagon responses were similar in high and low glucose conditions (P = 0.38). The direct effect of glucose on glucagon and amino acid-induced ureagenesis was assessed using isolated perfused mouse livers stimulated with a mixture of amino acids (VaminR, 10 mmol/L) and glucagon (10 nmol/L) during high and low glucose conditions. Urea production increased robustly but was independent of glucose levels (P = 0.95). To investigate the whole body effects of glucose on the liver-α cell axis, four groups of mice received intraperitoneal injections of glucose-Vamin (2 g/kg, + 3.5 µmol/g, respectively, G/V), saline-Vamin (S/V), glucose-saline (G/S), or saline-saline (S/S). Blood glucose did not differ significantly between G/S and G/V groups. Levels of glucagon and amino acids were similar in the G/V and S/V groups (P = 0.28). Amino acids may overrule the inhibitory effect of glucose on glucagon secretion and the liver-α cell axis may operate independently of glucose in mice.NEW & NOTEWORTHY Glucagon is an essential regulator of our metabolism. Recent evidence suggests that the physiological actions of glucagon reside in amino acid catabolism in the so-called liver-α cell axis, in which amino acids stimulate glucagon secretion and glucagon enhances hepatic amino acid catabolism. Here, it is demonstrated that this feedback system is independent of glycemia possibly explaining why hyperglycemia in diabetes may not suppress α cell secretion.
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Affiliation(s)
- Katharina Maruszczak
- Division of Gastroenterology, Hepatology and Nutrition, Department of Pediatrics, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
- Obesity Research Unit, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Christine Rasmussen
- Department for Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Frederik R Ceutz
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anne Ørgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Emilie Elmelund
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Michael M Richter
- Department for Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marie Winther-Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- NNF Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department for Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- NNF Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department for Clinical Biochemistry, Bispebjerg and Frederiksberg Hospital, University of Copenhagen, Copenhagen, Denmark
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24
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McGlone ER, Ansell TB, Dunsterville C, Song W, Carling D, Tomas A, Bloom SR, Sansom MSP, Tan T, Jones B. Hepatocyte cholesterol content modulates glucagon receptor signalling. Mol Metab 2022; 63:101530. [PMID: 35718339 PMCID: PMC9254120 DOI: 10.1016/j.molmet.2022.101530] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/13/2022] [Accepted: 06/13/2022] [Indexed: 11/24/2022] Open
Abstract
OBJECTIVE To determine whether glucagon receptor (GCGR) actions are modulated by cellular cholesterol levels. METHODS We determined the effects of experimental cholesterol depletion and loading on glucagon-mediated cAMP production, ligand internalisation and glucose production in human hepatoma cells, mouse and human hepatocytes. GCGR interactions with lipid bilayers were explored using coarse-grained molecular dynamic simulations. Glucagon responsiveness was measured in mice fed a high cholesterol diet with or without simvastatin to modulate hepatocyte cholesterol content. RESULTS GCGR cAMP signalling was reduced by higher cholesterol levels across different cellular models. Ex vivo glucagon-induced glucose output from mouse hepatocytes was enhanced by simvastatin treatment. Mice fed a high cholesterol diet had increased hepatic cholesterol and a blunted hyperglycaemic response to glucagon, both of which were partially reversed by simvastatin. Simulations identified likely membrane-exposed cholesterol binding sites on the GCGR, including a site where cholesterol is a putative negative allosteric modulator. CONCLUSIONS Our results indicate that cellular cholesterol content influences glucagon sensitivity and indicate a potential molecular basis for this phenomenon. This could be relevant to the pathogenesis of non-alcoholic fatty liver disease, which is associated with both hepatic cholesterol accumulation and glucagon resistance.
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Affiliation(s)
- Emma Rose McGlone
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom; Department of Surgery and Cancer, Imperial College London, London W12 0NN, United Kingdom.
| | - T Bertie Ansell
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
| | - Cecilia Dunsterville
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom.
| | - Wanling Song
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
| | - David Carling
- Cellular Stress Research Group, MRC London Institute of Medical Sciences, Imperial College London, London W12 0NN, United Kingdom.
| | - Alejandra Tomas
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom.
| | - Stephen R Bloom
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom.
| | - Mark S P Sansom
- Department of Biochemistry, University of Oxford, Oxford OX1 3QU, United Kingdom.
| | - Tricia Tan
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom.
| | - Ben Jones
- Department of Metabolism, Digestion and Reproduction, Imperial College London, London W12 0NN, United Kingdom.
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Holst JJ. Glucagon and other proglucagon-derived peptides in the pathogenesis of obesity. Front Nutr 2022; 9:964406. [PMID: 35990325 PMCID: PMC9386348 DOI: 10.3389/fnut.2022.964406] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 07/06/2022] [Indexed: 02/04/2023] Open
Abstract
Because of differential processing of the hormone precursor, proglucagon, numerous peptide products are released from the pancreatic alpha cells and the intestinal L-cells in which the (pro)glucagon gene is expressed. Of particular interest in relation to obesity are glucagon from the pancreas and oxyntomodulin and GLP-1 from the gut, all of which inhibit food intake, but the other products are also briefly discussed, because knowledge about these is required for selection and evaluation of the methods for measurement of the hormones. The distal intestinal L-cells also secrete the appetite-inhibiting hormone PYY. Characteristics of the secretion of the pancreatic and intestinal products are described, and causes of the hypersecretion of glucagon in obesity and type 2 diabetes are discussed. In contrast, the secretion of the products of the L-cells is generally impaired in obesity, raising questions about their role in the development of obesity. It is concluded that the impairment probably is secondary to obesity, but the lower plasma levels may contribute to the development.
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Affiliation(s)
- Jens Juul Holst
- The NovoNordisk Foundation Center for Basic Metabolic Research, Department of Biomedical Sciences, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
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Four weeks treatment with the GLP-1 receptor analogue liraglutide lowers liver fat and concomitantly circulating glucagon in individuals with overweight. Int J Obes (Lond) 2022; 46:2058-2062. [PMID: 35982119 DOI: 10.1038/s41366-022-01207-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 08/02/2022] [Accepted: 08/03/2022] [Indexed: 11/08/2022]
Abstract
We investigated the effect of pharmacologically induced weight loss on markers of glucagon resistance in individuals with overweight during treatment with the glucagon-like peptide-1 receptor agonist liraglutide. We performed an open-label study in 14 men with overweight (age 38 ± 11 years, BMI 32 ± 4 kg/m2) without simultaneously diabetes. Subjects were treated with liraglutide, initiated and titrated with 0.6 mg/day/week to reach the final dose of 3.0 mg/day. Subjects were examined at baseline, during titration (Week 4), after 2 weeks of steady state (Week 6) of final dosing of liraglutide and 3 weeks after discontinuation of liraglutide (follow-up). Study participants lost 3.3 ± 1.9 kg (3%) total body weight during the first 4 weeks of treatment with liraglutide. Simultaneously, liver fat content decreased from 12.4 ± 11.6% to 10.2 ± 11.1%, p = 0.025, whereas fat content in the spleen and subcutaneous tissue was unaltered. Markers of glucagon resistance, including plasma glucagon and the glucagon-alanine-index, also decreased significantly during treatment, but total and individual plasma amino acid concentrations did not. Insulin resistance (HOMA-IR) was unchanged during treatment, whereas insulin clearance increased. Treatment with the GLP-1 receptor analogue liraglutide decreased liver fat content, and simultaneously attenuated glucagon concentrations and the glucagon-alanine index in individuals with overweight without diabetes.
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Mendelian Randomization Analysis Identifies Blood Tyrosine Levels as a Biomarker of Non-Alcoholic Fatty Liver Disease. Metabolites 2022; 12:metabo12050440. [PMID: 35629944 PMCID: PMC9143809 DOI: 10.3390/metabo12050440] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/23/2022] [Revised: 05/02/2022] [Accepted: 05/11/2022] [Indexed: 02/06/2023] Open
Abstract
Non-alcoholic fatty liver disease (NAFLD) is a complex disease associated with premature mortality. Its diagnosis is challenging, and the identification of biomarkers causally influenced by NAFLD may be clinically useful. We aimed at identifying blood metabolites causally impacted by NAFLD using two-sample Mendelian randomization (MR) with validation in a population-based biobank. Our instrument for genetically predicted NAFLD included all independent genetic variants from a recent genome-wide association study. The outcomes included 123 blood metabolites from 24,925 individuals. After correction for multiple testing, a positive effect of NAFLD on plasma tyrosine levels but not on other metabolites was identified. This association was consistent across MR methods and was robust to outliers and pleiotropy. In observational analyses performed in the Estonian Biobank (10,809 individuals including 359 patients with NAFLD), after multivariable adjustment, tyrosine levels were positively associated with the presence of NAFLD (odds ratio per 1 SD increment = 1.23 [95% confidence interval = 1.12–1.36], p = 2.19 × 10−5). In a small proof-of-concept study on bariatric surgery patients, blood tyrosine levels were higher in patients with NAFLD than without. This study revealed a potentially causal effect of NAFLD on blood tyrosine levels, suggesting it may represent a new biomarker of NAFLD.
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28
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Bioinformatics study of the potential therapeutic effects of ginsenoside Rf in reversing nonalcoholic fatty liver disease. Biomed Pharmacother 2022; 149:112879. [PMID: 35358801 DOI: 10.1016/j.biopha.2022.112879] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2022] [Revised: 03/12/2022] [Accepted: 03/23/2022] [Indexed: 11/20/2022] Open
Abstract
OBJECTIVE Ginsenoside Rf, a tetracyclic triterpenoid only present in Panax ginseng, has been proven to relieve lipid metabolism and inflammatory reactions, which can be a potential treatment for nonalcoholic fatty liver disease (NAFLD). Therefore, this study aimed to reveal the underlying mechanisms of ginsenoside Rf in the treatment of early-stage NAFLD (NAFL) by using a bioinformatics method and biological experiments. METHODS Target genes associated with NAFL were screened from the Gene Expression Omnibus (GEO) database, a database repository of high-throughput gene expression data and hybridization arrays, chips, and microarrays. Subsequently, gene set enrichment analysis was performed by using Gene Ontology enrichment analysis tool. Then, the binding capacity between ginsenoside Rf and NAFL-related targets was evaluated by molecular docking. Finally, the FFA-induced HepG2 cell model treated with ginsenoside Rf was adopted to verify the effect of ginsenoside Rf and the related mechanisms. RESULTS There were 41 common differentially expressed genes in the GEO dataset. Gene Ontology and Reactome pathway enrichment analysis of the differentially expressed genes showed that many pathways could be related to the pathogenesis of NAFL, including those participating in the cytokine-mediated signaling pathway, G protein-coupled receptor signaling pathway, and response to lipopolysaccharide. Finally, the qRT-PCR analysis results indicated that ginsenoside Rf therapy could ameliorate the transcription of ANXA2, BAZ1A, DNMT3L and MMP9. CONCLUSION Our research discovered the relevant mechanisms and basic pharmacological effects of ginsenoside Rf in the treatment of NAFL. These results might facilitate the development of ginsenoside Rf as an alternative medication for NAFL.
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Mao X, Chen H, Lin AZ, Kim S, Burczynski ME, Na E, Halasz G, Sleeman MW, Murphy AJ, Okamoto H, Cheng X. Glutaminase 2 knockdown reduces hyperammonemia and associated lethality of urea cycle disorder mouse model. J Inherit Metab Dis 2022; 45:470-480. [PMID: 34988999 PMCID: PMC9302672 DOI: 10.1002/jimd.12474] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/29/2021] [Revised: 12/29/2021] [Accepted: 01/04/2022] [Indexed: 11/12/2022]
Abstract
Amino acids, the building blocks of proteins in the cells and tissues, are of fundamental importance for cell survival, maintenance, and proliferation. The liver plays a critical role in amino acid metabolism and detoxication of byproducts such as ammonia. Urea cycle disorders with hyperammonemia remain difficult to treat and eventually necessitate liver transplantation. In this study, ornithine transcarbamylase deficient (Otcspf-ash ) mouse model was used to test whether knockdown of a key glutamine metabolism enzyme glutaminase 2 (GLS2, gene name: Gls2) or glutamate dehydrogenase 1 (GLUD1, gene name: Glud1) could rescue the hyperammonemia and associated lethality induced by a high protein diet. We found that reduced hepatic expression of Gls2 but not Glud1 by AAV8-mediated delivery of a short hairpin RNA in Otcspf-ash mice diminished hyperammonemia and reduced lethality. Knockdown of Gls2 but not Glud1 in Otcspf-ash mice exhibited reduced body weight loss and increased plasma glutamine concentration. These data suggest that Gls2 hepatic knockdown could potentially help alleviate risk for hyperammonemia and other clinical manifestations of patients suffering from defects in the urea cycle.
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Affiliation(s)
- Xia Mao
- Regeneron PharmaceuticalsTarrytownNew YorkUSA
| | - Helen Chen
- Regeneron PharmaceuticalsTarrytownNew YorkUSA
| | | | - Sun Kim
- Regeneron PharmaceuticalsTarrytownNew YorkUSA
| | | | - Erqian Na
- Regeneron PharmaceuticalsTarrytownNew YorkUSA
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Maruszczak K, Radzikowski K, Schütz S, Mangge H, Bergsten P, Forslund A, Manell H, Pixner T, Ahlström H, Kullberg J, Mörwald K, Weghuber D. Determinants of hyperglucagonemia in pediatric non-alcoholic fatty liver disease. Front Endocrinol (Lausanne) 2022; 13:1004128. [PMID: 36133310 PMCID: PMC9483010 DOI: 10.3389/fendo.2022.1004128] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2022] [Accepted: 08/08/2022] [Indexed: 11/13/2022] Open
Abstract
OBJECTIVE Over the years, non-alcoholic fatty liver (NAFLD) disease has progressed to become the most frequent chronic liver disease in children and adolescents. The full pathology is not yet known, but disease progression leads to cirrhosis and hepatocellular carcinoma. Risk factors included hypercaloric diet, obesity, insulin resistance and genetics. Hyperglucagonemia appears to be a pathophysiological consequence of hepatic steatosis, thus, the hypothesis of the study is that hepatic fat accumulation leads to increased insulin resistance and impaired glucagon metabolism leading to hyperglucagonemia in pediatric NAFLD. METHODS 132 children and adolescents between 10 and 18 years, with varying degrees of obesity, were included in the study. Using Magnetic Resonance Imaging (MRI) average liver fat was determined, and patients were stratified as NAFLD (>5% liver fat content) and non-NAFLD (<5%). All patients underwent a standardized oral glucose tolerance test (OGTT). Additionally, anthropometric parameters (height, weight, BMI, waist circumference, hip circumference) such as lab data including lipid profile (triglycerides, HDL, LDL), liver function parameters (ALT, AST), uric acid, glucose metabolism (fasting insulin and glucagon, HbA1c, glucose 120 min) and indices evaluating insulin resistance (HIRI, SPISE, HOMA-IR, WBISI) were measured. RESULTS Children and adolescents with NAFLD had significantly higher fasting glucagon values compared to the non-NAFLD cohort (p=0.0079). In the NAFLD cohort univariate analysis of fasting glucagon was associated with BMI-SDS (p<0.01), visceral adipose tissue volume (VAT) (p<0.001), average liver fat content (p<0.001), fasting insulin concentration (p<0.001), triglycerides (p<0.001) and HDL (p=0.034). This correlation equally applied to all insulin indices HOMA-IR, WBISI, HIRI (all p<0.001) and SPISE (p<0.002). Multivariate analysis (R² adjusted 0.509) for the same subgroup identified HIRI (p=0.003) and VAT volume (p=0.017) as the best predictors for hyperglucagonemia. Average liver fat content is predictive in pediatric overweight and obesity but not NAFLD. CONCLUSIONS Children and adolescents with NAFLD have significantly higher fasting plasma glucagon values, which were best predicted by hepatic insulin resistance and visceral adipose tissue, but not average liver fat content.
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Affiliation(s)
- Katharina Maruszczak
- Department of Pediatrics, Obesity Research Unit, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Konrad Radzikowski
- Department of Pediatrics, Obesity Research Unit, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Sebastian Schütz
- Department of Mathematics, Paris Lodron University, Salzburg, Austria
| | - Harald Mangge
- Clinical Institute of Medical and Chemical Laboratory Diagnostics, Medical University of Graz, Graz, Austria
| | - Peter Bergsten
- Department of Medical Cell Biology, Uppsala University, Uppsala, Sweden
| | - Anders Forslund
- 5Department of Women’s and Children’s Health, Uppsala University, Uppsala, Sweden
| | - Hannes Manell
- 5Department of Women’s and Children’s Health, Uppsala University, Uppsala, Sweden
| | - Thomas Pixner
- Department of Pediatric and Adolescent Medicine, Salzkammergutklinikum Voecklabruck, Voecklabruck, Austria
| | - Håkan Ahlström
- Department of Radiology, Uppsala University, Uppsala, Sweden & Antaros Medical, BioVenture Hub, Mölndal, Sweden
| | - Joel Kullberg
- Department of Radiology, Uppsala University, Uppsala, Sweden & Antaros Medical, BioVenture Hub, Mölndal, Sweden
| | - Katharina Mörwald
- Department of Pediatrics, Obesity Research Unit, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
| | - Daniel Weghuber
- Department of Pediatrics, Obesity Research Unit, University Hospital Salzburg, Paracelsus Medical University, Salzburg, Austria
- *Correspondence: Daniel Weghuber,
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Huang HX, Shen LL, Huang HY, Zhao LH, Xu F, Zhang DM, Zhang XL, Chen T, Wang XQ, Xie Y, Su JB. Associations of Plasma Glucagon Levels with Estimated Glomerular Filtration Rate, Albuminuria and Diabetic Kidney Disease in Patients with Type 2 Diabetes Mellitus. Diabetes Metab J 2021; 45:868-879. [PMID: 33752319 PMCID: PMC8640146 DOI: 10.4093/dmj.2020.0149] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2020] [Accepted: 07/30/2020] [Indexed: 11/29/2022] Open
Abstract
BACKGROUND Type 2 diabetes mellitus (T2DM) is characterized by elevated fasting glucagon and impaired suppression of postprandial glucagon secretion, which may participate in diabetic complications. Therefore, we investigated the associations of plasma glucagon with estimated glomerular filtration rate (eGFR), albuminuria and diabetic kidney disease (DKD) in T2DM patients. METHODS Fasting glucagon and postchallenge glucagon (assessed by area under the glucagon curve [AUCgla]) levels were determined during oral glucose tolerance tests. Patients with an eGFR <60 mL/min/1.73 m2 and/or a urinary albumin-to-creatinine ratio (UACR) ≥30 mg/g who presented with diabetic retinopathy were identified as having DKD. RESULTS Of the 2,436 recruited patients, fasting glucagon was correlated with eGFR and UACR (r=-0.112 and r=0.157, respectively; P<0.001), and AUCgla was also correlated with eGFR and UACR (r=-0.267 and r=0.234, respectively; P<0.001). Moreover, 31.7% (n=771) presented with DKD; the prevalence of DKD was 27.3%, 27.6%, 32.5%, and 39.2% in the first (Q1), second (Q2), third (Q3), and fourth quartile (Q4) of fasting glucagon, respectively; and the corresponding prevalence for AUCgla was 25.9%, 22.7%, 33.7%, and 44.4%, respectively. Furthermore, after adjusting for other clinical covariates, the adjusted odds ratios (ORs; 95% confidence intervals) for DKD in Q2, Q3, and Q4 versus Q1 of fasting glucagon were 0.946 (0.697 to 1.284), 1.209 (0.895 to 1.634), and 1.521 (1.129 to 2.049), respectively; the corresponding ORs of AUCgla were 0.825 (0.611 to 1.114), 1.323 (0.989 to 1.769), and 2.066 (1.546 to 2.760), respectively. Additionally, when we restricted our analysis in patients with glycosylated hemoglobin <7.0% (n=471), we found fasting glucagon and AUCgla were still independently associated with DKD. CONCLUSION Both increased fasting and postchallenge glucagon levels were independently associated with DKD in T2DM patients.
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Affiliation(s)
- Hua-Xing Huang
- Department of General Medicine, First Affiliated Hospital of Soochow University, Suzhou, China
- Department of Nephrology, Affiliated Hospital 2 of Nantong University, and First People’s Hospital of Nantong City, Nantong, China
| | - Liang-Lan Shen
- Department of Nephrology, Affiliated Hospital 2 of Nantong University, and First People’s Hospital of Nantong City, Nantong, China
| | - Hai-Yan Huang
- Department of Endocrinology, Affiliated Hospital 2 of Nantong University, and First People’s Hospital of Nantong City, Nantong, China
| | - Li-Hua Zhao
- Department of Endocrinology, Affiliated Hospital 2 of Nantong University, and First People’s Hospital of Nantong City, Nantong, China
| | - Feng Xu
- Department of Endocrinology, Affiliated Hospital 2 of Nantong University, and First People’s Hospital of Nantong City, Nantong, China
| | - Dong-Mei Zhang
- Medical Research Center, Affiliated Hospital 2 of Nantong University, and First People’s Hospital of Nantong City, Nantong, China
| | - Xiu-Lin Zhang
- Department of Clinical Laboratory, Affiliated Hospital 2 of Nantong University, and First People’s Hospital of Nantong City, Nantong, China
| | - Tong Chen
- Department of Clinical Laboratory, Affiliated Hospital 2 of Nantong University, and First People’s Hospital of Nantong City, Nantong, China
| | - Xue-Qin Wang
- Department of Endocrinology, Affiliated Hospital 2 of Nantong University, and First People’s Hospital of Nantong City, Nantong, China
| | - Yan Xie
- Department of General Medicine, First Affiliated Hospital of Soochow University, Suzhou, China
- Corresponding authors: Yan Xie https://orcid.org/0000-0001-8118-7484 Department of General Medicine, First Affiliated Hospital of Soochow University, No. 188 Shizi Street, Suzhou 215006, China E-mail:
| | - Jian-Bin Su
- Department of Endocrinology, Affiliated Hospital 2 of Nantong University, and First People’s Hospital of Nantong City, Nantong, China
- Corresponding authors: Yan Xie https://orcid.org/0000-0001-8118-7484 Department of General Medicine, First Affiliated Hospital of Soochow University, No. 188 Shizi Street, Suzhou 215006, China E-mail:
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Otten J, Stomby A, Waling M, Chorell E, Ryberg M, Svensson M, Holst JJ, Olsson T. The liver-alpha-cell axis after a mixed meal and during weight loss in type 2 diabetes. Endocr Connect 2021; 10:1101-1110. [PMID: 34382579 PMCID: PMC8494406 DOI: 10.1530/ec-21-0171] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 08/11/2021] [Indexed: 11/16/2022]
Abstract
OBJECTIVE Glucagon and amino acids may be regulated in a feedback loop called the liver-alpha-cell axis with alanine or glutamine as suggested signal molecules. We assessed this concept in individuals with type 2 diabetes in the fasting state, after ingestion of a protein-rich meal, and during weight loss. Moreover, we investigated if postprandial glucagon secretion and hepatic insulin sensitivity were related. METHODS This is a secondary analysis of a 12-week weight-loss trial (Paleolithic diet ± exercise) in 29 individuals with type 2 diabetes. Before and after the intervention, plasma glucagon and amino acids were measured in the fasting state and during 180 min after a protein-rich mixed meal. Hepatic insulin sensitivity was measured using the hyperinsulinemic-euglycemic clamp with [6,6-2H2]glucose as a tracer. RESULTS The postprandial increase of plasma glucagon was associated with the postprandial increase of alanine and several other amino acids but not glutamine. In the fasted state and after the meal, glucagon levels were negatively correlated with hepatic insulin sensitivity (rS = -0.51/r = -0.58, respectively; both P < 0.05). Improved hepatic insulin sensitivity with weight loss was correlated with decreased postprandial glucagon response (r = -0.78; P < 0.001). CONCLUSIONS Several amino acids, notably alanine, but not glutamine could be key signals to the alpha cell to increase glucagon secretion. Amino acids may be part of a feedback mechanism as glucagon increases endogenous glucose production and ureagenesis in the liver. Moreover, postprandial glucagon secretion seems to be tightly related to hepatic insulin sensitivity.
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Affiliation(s)
- Julia Otten
- Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
- Correspondence should be addressed to J Otten:
| | - Andreas Stomby
- Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
- Region Jönköping County, Jönköping, Sweden
| | - Maria Waling
- Department of Food, Nutrition and Culinary Science, Umeå University, Umeå, Sweden
| | - Elin Chorell
- Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Mats Ryberg
- Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
| | - Michael Svensson
- Department of Community Medicine and Rehabilitation, Section for Sports Medicine, Umeå University, Umeå Sweden
| | - Jens Juul Holst
- NNF Center for Basic Metabolic Research and Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tommy Olsson
- Department of Public Health and Clinical Medicine, Umeå University, Umeå, Sweden
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Fernandez-Guerra P, Gonzalez-Ebsen AC, Boonen SE, Courraud J, Gregersen N, Mehlsen J, Palmfeldt J, Olsen RKJ, Brinth LS. Bioenergetic and Proteomic Profiling of Immune Cells in Myalgic Encephalomyelitis/Chronic Fatigue Syndrome Patients: An Exploratory Study. Biomolecules 2021; 11:961. [PMID: 34209852 PMCID: PMC8301912 DOI: 10.3390/biom11070961] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2021] [Revised: 06/17/2021] [Accepted: 06/18/2021] [Indexed: 01/22/2023] Open
Abstract
Myalgic encephalomyelitis/chronic fatigue syndrome (ME/CFS) is a heterogeneous, debilitating, and complex disease. Along with disabling fatigue, ME/CFS presents an array of other core symptoms, including autonomic nervous system (ANS) dysfunction, sustained inflammation, altered energy metabolism, and mitochondrial dysfunction. Here, we evaluated patients' symptomatology and the mitochondrial metabolic parameters in peripheral blood mononuclear cells (PBMCs) and plasma from a clinically well-characterised cohort of six ME/CFS patients compared to age- and gender-matched controls. We performed a comprehensive cellular assessment using bioenergetics (extracellular flux analysis) and protein profiles (quantitative mass spectrometry-based proteomics) together with self-reported symptom measures of fatigue, ANS dysfunction, and overall physical and mental well-being. This ME/CFS cohort presented with severe fatigue, which correlated with the severity of ANS dysfunction and overall physical well-being. PBMCs from ME/CFS patients showed significantly lower mitochondrial coupling efficiency. They exhibited proteome alterations, including altered mitochondrial metabolism, centred on pyruvate dehydrogenase and coenzyme A metabolism, leading to a decreased capacity to provide adequate intracellular ATP levels. Overall, these results indicate that PBMCs from ME/CFS patients have a decreased ability to fulfill their cellular energy demands.
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Affiliation(s)
- Paula Fernandez-Guerra
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, 8200 Aarhus, Denmark; (A.C.G.-E.); (N.G.); (J.P.)
- KMEB, Department of Endocrinology, Odense University Hospital and Department of Clinical Research, University of Southern Denmark, 5000 Odense, Denmark
| | - Ana C. Gonzalez-Ebsen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, 8200 Aarhus, Denmark; (A.C.G.-E.); (N.G.); (J.P.)
| | - Susanne E. Boonen
- Department of Clinical Genetics, Odense University Hospital, 5000 Odense, Denmark;
| | - Julie Courraud
- Section for Clinical Mass Spectrometry, Danish Center for Neonatal Screening, Department of Congenital Disorders, Statens Serum Institute, 2300 Copenhagen, Denmark;
| | - Niels Gregersen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, 8200 Aarhus, Denmark; (A.C.G.-E.); (N.G.); (J.P.)
| | - Jesper Mehlsen
- Section for Surgical Pathophysiology, Juliane Marie Center, Rigshospitalet, 2100 Copenhagen, Denmark;
| | - Johan Palmfeldt
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, 8200 Aarhus, Denmark; (A.C.G.-E.); (N.G.); (J.P.)
| | - Rikke K. J. Olsen
- Research Unit for Molecular Medicine, Department of Clinical Medicine, Aarhus University and Aarhus University Hospital, 8200 Aarhus, Denmark; (A.C.G.-E.); (N.G.); (J.P.)
| | - Louise Schouborg Brinth
- Department of Clinical Physiology and Nuclear Medicine, Nordsjaellands Hospital, 2400 Hilleroed, Denmark;
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Zeigerer A, Sekar R, Kleinert M, Nason S, Habegger KM, Müller TD. Glucagon's Metabolic Action in Health and Disease. Compr Physiol 2021; 11:1759-1783. [PMID: 33792899 PMCID: PMC8513137 DOI: 10.1002/cphy.c200013] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Discovered almost simultaneously with insulin, glucagon is a pleiotropic hormone with metabolic action that goes far beyond its classical role to increase blood glucose. Albeit best known for its ability to directly act on the liver to increase de novo glucose production and to inhibit glycogen breakdown, glucagon lowers body weight by decreasing food intake and by increasing metabolic rate. Glucagon further promotes lipolysis and lipid oxidation and has positive chronotropic and inotropic effects in the heart. Interestingly, recent decades have witnessed a remarkable renaissance of glucagon's biology with the acknowledgment that glucagon has pharmacological value beyond its classical use as rescue medication to treat severe hypoglycemia. In this article, we summarize the multifaceted nature of glucagon with a special focus on its hepatic action and discuss the pharmacological potential of either agonizing or antagonizing the glucagon receptor for health and disease. © 2021 American Physiological Society. Compr Physiol 11:1759-1783, 2021.
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Affiliation(s)
- Anja Zeigerer
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Revathi Sekar
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Maximilian Kleinert
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Shelly Nason
- Comprehensive Diabetes Center, Department of Medicine - Endocrinology, Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Kirk M. Habegger
- Comprehensive Diabetes Center, Department of Medicine - Endocrinology, Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Timo D. Müller
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany
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Gar C, Haschka SJ, Kern-Matschilles S, Rauch B, Sacco V, Prehn C, Adamski J, Seissler J, Wewer Albrechtsen NJ, Holst JJ, Lechner A. The liver-alpha cell axis associates with liver fat and insulin resistance: a validation study in women with non-steatotic liver fat levels. Diabetologia 2021; 64:512-520. [PMID: 33275161 PMCID: PMC7864806 DOI: 10.1007/s00125-020-05334-x] [Citation(s) in RCA: 22] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/01/2020] [Accepted: 10/09/2020] [Indexed: 02/07/2023]
Abstract
AIMS/HYPOTHESIS Many individuals who develop type 2 diabetes also display increased glucagon levels (hyperglucagonaemia), which we have previously found to be associated with the metabolic syndrome. The concept of a liver-alpha cell axis provides a possible link between hyperglucagonaemia and elevated liver fat content, a typical finding in the metabolic syndrome. However, this association has only been studied in individuals with non-alcoholic fatty liver disease. Hence, we searched for a link between the liver and the alpha cells in individuals with non-steatotic levels of liver fat content. We hypothesised that the glucagon-alanine index, an indicator of the functional integrity of the liver-alpha cell axis, would associate with liver fat and insulin resistance in our cohort of women with low levels of liver fat. METHODS We analysed data from 79 individuals participating in the Prediction, Prevention and Subclassification of Type 2 Diabetes (PPSDiab) study, a prospective observational study of young women at low to high risk for the development of type 2 diabetes. Liver fat content was determined by MRI. Insulin resistance was calculated as HOMA-IR. We conducted Spearman correlation analyses of liver fat content and HOMA-IR with the glucagon-alanine index (the product of fasting plasma levels of glucagon and alanine). The prediction of the glucagon-alanine index by liver fat or HOMA-IR was tested in multivariate linear regression analyses in the whole cohort as well as after stratification for liver fat content ≤0.5% (n = 39) or >0.5% (n = 40). RESULTS The glucagon-alanine index significantly correlated with liver fat and HOMA-IR in the entire cohort (ρ = 0.484, p < 0.001 and ρ = 0.417, p < 0.001, respectively). These associations resulted from significant correlations in participants with a liver fat content >0.5% (liver fat, ρ = 0.550, p < 0.001; HOMA-IR, ρ = 0.429, p = 0.006). In linear regression analyses, the association of the glucagon-alanine index with liver fat remained significant after adjustment for age and HOMA-IR in all participants and in those with liver fat >0.5% (β = 0.246, p = 0.0.23 and β = 0.430, p = 0.007, respectively) but not in participants with liver fat ≤0.5% (β = -0.184, p = 0.286). CONCLUSIONS/INTERPRETATION We reproduced the previously reported association of liver fat content and HOMA-IR with the glucagon-alanine index in an independent study cohort of young women with low to high risk for type 2 diabetes. Furthermore, our data indicates an insulin-resistance-independent association of liver fat content with the glucagon-alanine index. In summary, our study supports the concept that even lower levels of liver fat (from 0.5%) are connected to relative hyperglucagonaemia, reflecting an imminent impairment of the liver-alpha cell axis.
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Affiliation(s)
- Christina Gar
- Diabetes Research Group, Department of Medicine IV, University Hospital, LMU Munich, Munich, Germany
- Clinical Cooperation Group Type 2 Diabetes, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Stefanie J Haschka
- Diabetes Research Group, Department of Medicine IV, University Hospital, LMU Munich, Munich, Germany
- Clinical Cooperation Group Type 2 Diabetes, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Stefanie Kern-Matschilles
- Diabetes Research Group, Department of Medicine IV, University Hospital, LMU Munich, Munich, Germany
- Clinical Cooperation Group Type 2 Diabetes, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Barbara Rauch
- Diabetes Research Group, Department of Medicine IV, University Hospital, LMU Munich, Munich, Germany
- Clinical Cooperation Group Type 2 Diabetes, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Vanessa Sacco
- Diabetes Research Group, Department of Medicine IV, University Hospital, LMU Munich, Munich, Germany
- Clinical Cooperation Group Type 2 Diabetes, Helmholtz Zentrum München, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Cornelia Prehn
- Research Unit Molecular Endocrinology and Metabolism, Genome Analysis Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
| | - Jerzy Adamski
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Research Unit Molecular Endocrinology and Metabolism, Genome Analysis Center, Helmholtz Zentrum München, German Research Center for Environmental Health, Neuherberg, Germany
- Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, Singapore
- Chair of Experimental Genetics, Technical University of Munich, Freising-Weihenstephan, Germany
| | - Jochen Seissler
- Diabetes Research Group, Department of Medicine IV, University Hospital, LMU Munich, Munich, Germany
| | - Nicolai J Wewer Albrechtsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
- Novo Nordisk Foundation (NNF) Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation (NNF) Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Andreas Lechner
- Diabetes Research Group, Department of Medicine IV, University Hospital, LMU Munich, Munich, Germany.
- Clinical Cooperation Group Type 2 Diabetes, Helmholtz Zentrum München, Neuherberg, Germany.
- German Center for Diabetes Research (DZD), Neuherberg, Germany.
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Bai X, Jia J, Kang Q, Fu Y, Zhou Y, Zhong Y, Zhang C, Li M. Integrated Metabolomics and Lipidomics Analysis Reveal Remodeling of Lipid Metabolism and Amino Acid Metabolism in Glucagon Receptor-Deficient Zebrafish. Front Cell Dev Biol 2021; 8:605979. [PMID: 33520988 PMCID: PMC7841139 DOI: 10.3389/fcell.2020.605979] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2020] [Accepted: 11/30/2020] [Indexed: 12/17/2022] Open
Abstract
The glucagon receptor (GCGR) is activated by glucagon and is essential for glucose, amino acid, and lipid metabolism of animals. GCGR blockade has been demonstrated to induce hypoglycemia, hyperaminoacidemia, hyperglucagonemia, decreased adiposity, hepatosteatosis, and pancreatic α cells hyperplasia in organisms. However, the mechanism of how GCGR regulates these physiological functions is not yet very clear. In our previous study, we revealed that GCGR regulated metabolic network at transcriptional level by RNA-seq using GCGR mutant zebrafish (gcgr -/-). Here, we further performed whole-organism metabolomics and lipidomics profiling on wild-type and gcgr -/- zebrafish to study the changes of metabolites. We found 107 significantly different metabolites from metabolomics analysis and 87 significantly different lipids from lipidomics analysis. Chemical substance classification and pathway analysis integrated with transcriptomics data both revealed that amino acid metabolism and lipid metabolism were remodeled in gcgr-deficient zebrafish. Similar to other studies, our study showed that gcgr -/- zebrafish exhibited decreased ureagenesis and impaired cholesterol metabolism. More interestingly, we found that the glycerophospholipid metabolism was disrupted, the arachidonic acid metabolism was up-regulated, and the tryptophan metabolism pathway was down-regulated in gcgr -/- zebrafish. Based on the omics data, we further validated our findings by revealing that gcgr -/- zebrafish exhibited dampened melatonin diel rhythmicity and increased locomotor activity. These global omics data provide us a better understanding about the role of GCGR in regulating metabolic network and new insight into GCGR physiological functions.
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Affiliation(s)
- Xuanxuan Bai
- Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China.,Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jianxin Jia
- Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - Qi Kang
- Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China.,State Key Laboratory of Cellular Stress Biology, School of Life Sciences, Xiamen University, Xiamen, China
| | - Yadong Fu
- Center for Circadian Clocks, Soochow University, Suzhou, China.,School of Biology and Basic Medical Sciences, Medical College, Soochow University, Suzhou, China
| | - You Zhou
- Division of Infection and Immunity, School of Medicine, Systems Immunity University Research Institute, Cardiff University, Cardiff, United Kingdom
| | - Yingbin Zhong
- Center for Circadian Clocks, Soochow University, Suzhou, China.,School of Biology and Basic Medical Sciences, Medical College, Soochow University, Suzhou, China
| | - Chao Zhang
- Translational Medical Center for Stem Cell Therapy and Institute for Regenerative Medicine, Shanghai East Hospital, Shanghai Key Laboratory of Signaling and Disease Research, Frontier Science Center for Stem Cell Research, School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Mingyu Li
- Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
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Cavino K, Sung B, Su Q, Na E, Kim J, Cheng X, Gromada J, Okamoto H. Glucagon Receptor Inhibition Reduces Hyperammonemia and Lethality in Male Mice with Urea Cycle Disorder. Endocrinology 2021; 162:5988952. [PMID: 33206168 DOI: 10.1210/endocr/bqaa211] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/07/2020] [Indexed: 12/14/2022]
Abstract
The liver plays a critical role in maintaining ammonia homeostasis. Urea cycle defects, liver injury, or failure and glutamine synthetase (GS) deficiency result in hyperammonemia, serious clinical conditions, and lethality. In this study we used a mouse model with a defect in the urea cycle enzyme ornithine transcarbamylase (Otcspf-ash) to test the hypothesis that glucagon receptor inhibition using a monoclonal blocking antibody will reduce the hyperammonemia and associated lethality induced by a high-protein diet, which exacerbates disease. We found reduced expression of glutaminase, which degrades glutamine and increased expression of GS in livers of Otcspf-ash mice treated with the glucagon receptor blocking antibody. The gene expression changes favor ammonia consumption and were accompanied by increased circulating glutamine levels and diminished hyperammonemia. Otcspf-ash mice treated with the glucagon receptor-blocking antibody gained lean and body mass and had increased survival. These data suggest that glucagon receptor inhibition using a monoclonal antibody could reduce the risk for hyperammonemia and other clinical manifestations of patients suffering from defects in the urea cycle, liver injury, or failure and GS deficiency.
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Affiliation(s)
- Katie Cavino
- Regeneron Pharmaceuticals, Tarrytown, New York USA
| | - Biin Sung
- Regeneron Pharmaceuticals, Tarrytown, New York USA
| | - Qi Su
- Regeneron Pharmaceuticals, Tarrytown, New York USA
| | - Erqian Na
- Regeneron Pharmaceuticals, Tarrytown, New York USA
| | - Jinrang Kim
- Regeneron Pharmaceuticals, Tarrytown, New York USA
| | - Xiping Cheng
- Regeneron Pharmaceuticals, Tarrytown, New York USA
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Galsgaard KD. The Vicious Circle of Hepatic Glucagon Resistance in Non-Alcoholic Fatty Liver Disease. J Clin Med 2020; 9:jcm9124049. [PMID: 33333850 PMCID: PMC7765287 DOI: 10.3390/jcm9124049] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2020] [Revised: 12/07/2020] [Accepted: 12/08/2020] [Indexed: 02/08/2023] Open
Abstract
A key criterion for the most common chronic liver disease—non-alcoholic fatty liver disease (NAFLD)—is an intrahepatic fat content above 5% in individuals who are not using steatogenic agents or having significant alcohol intake. Subjects with NAFLD have increased plasma concentrations of glucagon, and emerging evidence indicates that subjects with NAFLD may show hepatic glucagon resistance. For many years, glucagon has been thought of as the counterregulatory hormone to insulin with a primary function of increasing blood glucose concentrations and protecting against hypoglycemia. However, in recent years, glucagon has re-emerged as an important regulator of other metabolic processes including lipid and amino acid/protein metabolism. This review discusses the evidence that in NAFLD, hepatic glucagon resistance may result in a dysregulated lipid and amino acid/protein metabolism, leading to excess accumulation of fat, hyperglucagonemia, and increased oxidative stress contributing to the worsening/progression of NAFLD.
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Affiliation(s)
- Katrine D. Galsgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark; ; Tel.: +45-6044-6145
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
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39
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Winther-Sørensen M, Galsgaard KD, Santos A, Trammell SAJ, Sulek K, Kuhre RE, Pedersen J, Andersen DB, Hassing AS, Dall M, Treebak JT, Gillum MP, Torekov SS, Windeløv JA, Hunt JE, Kjeldsen SAS, Jepsen SL, Vasilopoulou CG, Knop FK, Ørskov C, Werge MP, Bisgaard HC, Eriksen PL, Vilstrup H, Gluud LL, Holst JJ, Wewer Albrechtsen NJ. Glucagon acutely regulates hepatic amino acid catabolism and the effect may be disturbed by steatosis. Mol Metab 2020; 42:101080. [PMID: 32937194 PMCID: PMC7560169 DOI: 10.1016/j.molmet.2020.101080] [Citation(s) in RCA: 62] [Impact Index Per Article: 15.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/10/2020] [Revised: 08/28/2020] [Accepted: 09/09/2020] [Indexed: 12/12/2022] Open
Abstract
OBJECTIVE Glucagon is well known to regulate blood glucose but may be equally important for amino acid metabolism. Plasma levels of amino acids are regulated by glucagon-dependent mechanism(s), while amino acids stimulate glucagon secretion from alpha cells, completing the recently described liver-alpha cell axis. The mechanisms underlying the cycle and the possible impact of hepatic steatosis are unclear. METHODS We assessed amino acid clearance in vivo in mice treated with a glucagon receptor antagonist (GRA), transgenic mice with 95% reduction in alpha cells, and mice with hepatic steatosis. In addition, we evaluated urea formation in primary hepatocytes from ob/ob mice and humans, and we studied acute metabolic effects of glucagon in perfused rat livers. We also performed RNA sequencing on livers from glucagon receptor knock-out mice and mice with hepatic steatosis. Finally, we measured individual plasma amino acids and glucagon in healthy controls and in two independent cohorts of patients with biopsy-verified non-alcoholic fatty liver disease (NAFLD). RESULTS Amino acid clearance was reduced in mice treated with GRA and mice lacking endogenous glucagon (loss of alpha cells) concomitantly with reduced production of urea. Glucagon administration markedly changed the secretion of rat liver metabolites and within minutes increased urea formation in mice, in perfused rat liver, and in primary human hepatocytes. Transcriptomic analyses revealed that three genes responsible for amino acid catabolism (Cps1, Slc7a2, and Slc38a2) were downregulated both in mice with hepatic steatosis and in mice with deletion of the glucagon receptor. Cultured ob/ob hepatocytes produced less urea upon stimulation with mixed amino acids, and amino acid clearance was lower in mice with hepatic steatosis. Glucagon-induced ureagenesis was impaired in perfused rat livers with hepatic steatosis. Patients with NAFLD had hyperglucagonemia and increased levels of glucagonotropic amino acids, including alanine in particular. Both glucagon and alanine levels were reduced after diet-induced reduction in Homeostatic Model Assessment for Insulin Resistance (HOMA-IR, a marker of hepatic steatosis). CONCLUSIONS Glucagon regulates amino acid metabolism both non-transcriptionally and transcriptionally. Hepatic steatosis may impair glucagon-dependent enhancement of amino acid catabolism.
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Affiliation(s)
- Marie Winther-Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Katrine D Galsgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Alberto Santos
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Samuel A J Trammell
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Karolina Sulek
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Rune E Kuhre
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Pedersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Daniel B Andersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Anna S Hassing
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Morten Dall
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jonas T Treebak
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Matthew P Gillum
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Signe S Torekov
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Johanne A Windeløv
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jenna E Hunt
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sasha A S Kjeldsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Sara L Jepsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Catherine G Vasilopoulou
- Department of Proteomics and Signal Transduction, Max Planck Institute of Biochemistry, Munich, Germany
| | - Filip K Knop
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark; Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Steno Diabetes Center Copenhagen, Gentofte, Denmark
| | - Cathrine Ørskov
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mikkel P Werge
- Gastrounit, Hvidovre Hospital, University of Copenhagen, Hvidovre, Denmark
| | - Hanne Cathrine Bisgaard
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Peter Lykke Eriksen
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Hendrik Vilstrup
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Lise Lotte Gluud
- Gastrounit, Hvidovre Hospital, University of Copenhagen, Hvidovre, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.
| | - Nicolai J Wewer Albrechtsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department for Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.
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40
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Pedersen JS, Rygg MO, Kristiansen VB, Olsen BH, Serizawa RR, Holst JJ, Madsbad S, Gluud LL, Bendtsen F, Wewer Albrechtsen NJ. Nonalcoholic Fatty Liver Disease Impairs the Liver-Alpha Cell Axis Independent of Hepatic Inflammation and Fibrosis. Hepatol Commun 2020; 4:1610-1623. [PMID: 33163832 PMCID: PMC7603528 DOI: 10.1002/hep4.1562] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2020] [Revised: 05/22/2020] [Accepted: 05/31/2020] [Indexed: 01/01/2023] Open
Abstract
Nonalcoholic fatty liver disease (NAFLD) is associated with impaired hepatic actions of glucagon and insulin. Glucagon and amino acids are linked in an endocrine feedback circuit, the liver-alpha cell axis, that may be disrupted by NAFLD. We investigated how NAFLD severity affects glucagon and insulin resistance in individuals with obesity and whether bariatric surgery improves these parameters. Plasma and liver biopsies from 33 individuals with obesity (collectively, OBE) were obtained before and 12 months after bariatric surgery (Roux-en-Y gastric bypass [RYGB] or sleeve gastrectomy [SG]). Nine healthy control individuals (collectively, CON) undergoing cholecystectomy were used as a comparison group. The NAFLD activity score (NAS) was used to subdivide study participants into the following groups: OBE-no steatosis, OBE+steatosis, and nonalcoholic steatohepatitis (NASH) and/or grade 2 fibrosis (Fib) (OBE-NASH-Fib). Measurements of amino acids by targeted metabolomics and glucagon were performed. Glucagon, amino acids (P < 0.05), and the glucagon-alanine index, a validated surrogate marker of glucagon resistance, were increased in OBE by 60%, 56%, and 61%, respectively, when compared with CON but irrespective of NAFLD severity. In contrast, markers of hepatic insulin resistance increased concomitantly with NAS. Hyperglucagonemia resolved in OBE-no steatosis and OBE+steatosis but not in OBE-NASH-Fib (median, 7.0; interquartile range, 5.0-9.8 pmol/L), regardless of improvement in insulin resistance and NAS. The type of surgery that participants underwent had no effect on metabolic outcomes. Conclusion: Glucagon resistance to amino acid metabolism exists in individuals with NAFLD independent of NAS severity. Patients with NASH showed persistent hyperglucagonemia 12 months after bariatric surgery, indicating that a disrupted liver-alpha cell may remain in NAFLD despite major improvement in liver histology.
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Affiliation(s)
- Julie Steen Pedersen
- GastrounitMedical DivisionCopenhagen University Hospital HvidovreHvidovreDenmark
| | - Marte Opseth Rygg
- GastrounitMedical DivisionCopenhagen University Hospital HvidovreHvidovreDenmark
| | | | - Beth Hærstedt Olsen
- Department of Nuclear Medicine and Functional Imaging, Ultrasound SectionCopenhagen University Hospital HvidovreHvidovreDenmark
| | | | - Jens Juul Holst
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
| | - Sten Madsbad
- Department of EndocrinologyCopenhagen University Hospital HvidovreHvidovreDenmark
| | - Lise Lotte Gluud
- GastrounitMedical DivisionCopenhagen University Hospital HvidovreHvidovreDenmark
| | - Flemming Bendtsen
- GastrounitMedical DivisionCopenhagen University Hospital HvidovreHvidovreDenmark
| | - Nicolai Jacob Wewer Albrechtsen
- Department of Biomedical SciencesFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
- Department of Clinical Biochemistry, RigshospitaletUniversity of CopenhagenCopenhagenDenmark
- Novo Nordisk Foundation Center for Protein ResearchFaculty of Health and Medical SciencesUniversity of CopenhagenCopenhagenDenmark
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Abstract
Background The prevalence and incidence of type 2 diabetes (T2D), representing >90% of all cases of diabetes, are increasing rapidly worldwide. Identification of individuals at high risk of developing diabetes is of great importance as early interventions might delay or even prevent full-blown disease. T2D is a complex disease caused by multiple genetic loci in interplay with lifestyle and environmental factors. Recently over 400 distinct association signals were published; these explain 18% of the risk of T2D. Scope of review In this review there is a major focus on risk factors and genetic and non-genetic biomarkers for the risk of T2D identified especially in large prospective population-based studies, and studies testing causality of the biomarkers for T2D in Mendelian randomization studies. Another focus is on understanding genome-phenome interplay in the classification of individuals with T2D into subgroups. Major conclusions Several recent large population-based studies and their meta-analyses have identified multiple potential genetic and non-genetic biomarkers for the risk of T2D. Combination of genetic variants and physiologically characterized pathways improves the classification of individuals with T2D into subgroups, and is also paving the way to a precision medicine approach, in T2D.
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Affiliation(s)
- Markku Laakso
- Institute of Clinical Medicine, Internal Medicine, University of Eastern Finland, 70210, Kuopio, Finland.
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Different Malabsorptive Obesity Surgery Interventions Result in Distinct Postprandial Amino Acid Metabolomic Signatures. Obes Surg 2020; 30:4019-4028. [PMID: 32564307 DOI: 10.1007/s11695-020-04774-z] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2020] [Revised: 06/05/2020] [Accepted: 06/05/2020] [Indexed: 12/14/2022]
Abstract
PURPOSE Biliopancreatic diversion with duodenal switch (BPD-DS) is an effective weight loss surgical procedure. Yet, BPD-DS is technically difficult to perform and carries a higher risk of nutrient deficiencies as compared with other surgical interventions. Single-anastomosis duodeno-ileal bypass with sleeve gastrectomy (SADI-S) is a modified BPD-DS procedure conceived with the aim of decreasing the technical complexity, while retaining the weight loss efficiency. Whether the two surgical procedures diverge in nutrient absorption rates and malnutrition risk is still matter of debate. Our aim was to determine if postprandial nutrient absorption rates are different in patients subjected to BPD-DS or SADI-S for weight loss. MATERIALS AND METHODS Plasma amino acid metabolomic profiling during mixed-meal tolerance test (MMTT) was performed in subjects (N = 18) submitted to BPD-DS (n = 9) or SADI-S (n = 9) 1.6 ± 0.1 years earlier. RESULTS Patients submitted to SADI-S or BPD-DS presented distinct postprandial metabolomic profiles. Postprandial excursions of total and essential amino acids-leucine, isoleucine, and valine-were higher after SADI-S as compared with BPD-DS. CONCLUSION Our study demonstrates that a simplified malabsorptive bariatric surgery procedure SADI-S results in greater essential branched-chain amino acid absorption when compared with the classical BPD-DS intervention. These findings suggest that SADI-S can potentially lower lifetime risk of postoperative protein malnutrition, as well as have a positive impact on systemic metabolism and glucose homeostasis.
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Suppli MP, Bagger JI, Lund A, Demant M, van Hall G, Strandberg C, Kønig MJ, Rigbolt K, Langhoff JL, Wewer Albrechtsen NJ, Holst JJ, Vilsbøll T, Knop FK. Glucagon Resistance at the Level of Amino Acid Turnover in Obese Subjects With Hepatic Steatosis. Diabetes 2020; 69:1090-1099. [PMID: 31974144 DOI: 10.2337/db19-0715] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/19/2019] [Accepted: 01/13/2020] [Indexed: 12/12/2022]
Abstract
Glucagon secretion is regulated by circulating glucose, but it has turned out that amino acids also play an important role and that hepatic amino acid metabolism and glucagon are linked in a mutual feedback cycle, the liver-α-cell axis. On the basis of this knowledge, we hypothesized that hepatic steatosis might impair glucagon's action on hepatic amino acid metabolism and lead to hyperaminoacidemia and hyperglucagonemia. We subjected 15 healthy lean and 15 obese steatotic male participants to a pancreatic clamp with somatostatin and evaluated hepatic glucose and amino acid metabolism when glucagon was at basal levels and at high physiological levels. The degree of steatosis was evaluated from liver biopsy specimens. Total RNA sequencing of liver biopsy specimens from the obese steatotic individuals revealed perturbations in the expression of genes predominantly involved in amino acid metabolism. This group was characterized by fasting hyperglucagonemia, hyperaminoacidemia, and no lowering of amino acid levels in response to high levels of glucagon. Endogenous glucose production was similar between lean and obese individuals. Our results suggest that hepatic steatosis causes resistance to the effect of glucagon on amino acid metabolism. This results in increased amino acid concentrations and increased glucagon secretion, providing a likely explanation for fatty liver-associated hyperglucagonemia.
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Affiliation(s)
- Malte P Suppli
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Jonatan I Bagger
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Asger Lund
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Mia Demant
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Gerrit van Hall
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Clinical Metabolomics Core Facility, Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Charlotte Strandberg
- Department of Radiology, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | - Merete J Kønig
- Department of Radiology, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
| | | | - Jill L Langhoff
- Department of Pathology, Herlev Hospital, University of Copenhagen, Herlev, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Tina Vilsbøll
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, Gentofte, Denmark
| | - Filip K Knop
- Center for Clinical Metabolic Research, Gentofte Hospital, University of Copenhagen, Hellerup, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Steno Diabetes Center Copenhagen, Gentofte, Denmark
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44
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Martinussen C, Veedfald S, Dirksen C, Bojsen-Møller KN, Svane MS, Wewer Albrechtsen NJ, van Hall G, Kristiansen VB, Fenger M, Holst JJ, Madsbad S. The effect of acute dual SGLT1/SGLT2 inhibition on incretin release and glucose metabolism after gastric bypass surgery. Am J Physiol Endocrinol Metab 2020; 318:E956-E964. [PMID: 32182123 DOI: 10.1152/ajpendo.00023.2020] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Enhanced meal-related enteroendocrine secretion, particularly of glucagon-like peptide-1 (GLP-1), contributes to weight-loss and improved glycemia after Roux-en-Y gastric bypass (RYGB). Dietary glucose drives GLP-1 and glucose-dependent insulinotropic polypeptide (GIP) secretion postoperatively. Understanding how glucose triggers incretin secretion following RYGB could lead to new treatments of diabetes and obesity. In vitro, incretin release depends on glucose absorption via sodium-glucose cotransporter 1 (SGLT1). We investigated the importance of SGLT1/SGLT2 for enteropancreatic hormone concentrations and glucose metabolism after RYGB in a randomized, controlled, crossover study. Ten RYGB-operated patients ingested 50 g of oral glucose with and without acute pretreatment with 600 mg of the SGLT1/SGLT2-inhibitor canagliflozin. Paracetamol and 3-O-methyl-d-glucopyranose (3-OMG) were added to the glucose drink to evaluate rates of intestinal entry and absorption of glucose, respectively. Blood samples were collected for 4 h. The primary outcome was 4-h plasma GLP-1 (incremental area-under the curve, iAUC). Secondary outcomes included glucose, GIP, insulin, and glucagon. Canagliflozin delayed glucose absorption (time-to-peak 3-OMG: 50 vs. 132 min, P < 0.01) but did not reduce iAUC GLP-1 (6,067 vs. 7,273·min·pmol-1·L-1, P = 0.23), although peak GLP-1 concentrations were lowered (-28%, P = 0.03). Canagliflozin reduced GIP (iAUC -28%, P = 0.01; peak concentrations -57%, P < 0.01), insulin, and glucose excursions, whereas plasma glucagon (AUC 3,216 vs. 4,160 min·pmol·L-1, P = 0.02) and amino acids were increased. In conclusion, acute SGLT1/SGLT2-inhibition during glucose ingestion did not reduce 4-h plasma GLP-1 responses in RYGB-patients but attenuated the early rise in GLP-1, GIP, and insulin, whereas late glucagon concentrations were increased. The results suggest that SGLT1-mediated glucose absorption contributes to incretin hormone secretion after RYGB.
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Affiliation(s)
- Christoffer Martinussen
- Department of Endocrinology, Hvidovre Hospital, Hvidovre, Denmark
- Danish Diabetes Academy, Odense, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Simon Veedfald
- Department of Endocrinology, Hvidovre Hospital, Hvidovre, Denmark
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Carsten Dirksen
- Department of Endocrinology, Hvidovre Hospital, Hvidovre, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Kirstine N Bojsen-Møller
- Department of Endocrinology, Hvidovre Hospital, Hvidovre, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Maria S Svane
- Department of Endocrinology, Hvidovre Hospital, Hvidovre, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
| | - Gerrit van Hall
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Clinical Metabolomics Core Facility, Clinical Biochemistry, Rigshospitalet, Copenhagen, Denmark
| | - Viggo B Kristiansen
- Department of Surgical Gastroenterology, Hvidovre Hospital, Hvidovre, Denmark
| | - Mogens Fenger
- Department of Clinical Biochemistry, Hvidovre Hospital, Hvidovre, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
| | - Sten Madsbad
- Department of Endocrinology, Hvidovre Hospital, Hvidovre, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, University of Copenhagen, Copenhagen, Denmark
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45
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Galsgaard KD, Pedersen J, Kjeldsen SAS, Winther-Sørensen M, Stojanovska E, Vilstrup H, Ørskov C, Wewer Albrechtsen NJ, Holst JJ. Glucagon receptor signaling is not required for N-carbamoyl glutamate- and l-citrulline-induced ureagenesis in mice. Am J Physiol Gastrointest Liver Physiol 2020; 318:G912-G927. [PMID: 32174131 DOI: 10.1152/ajpgi.00294.2019] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Glucagon regulates the hepatic amino acid metabolism and increases ureagenesis. Ureagenesis is activated by N-acetylglutamate (NAG), formed via activation of N-acetylglutamate synthase (NAGS). With the aim to identify the steps whereby glucagon both acutely and chronically regulates ureagenesis, we investigated whether glucagon receptor-mediated activation of ureagenesis is required in a situation where NAGS activity and/or NAG levels are sufficient to activate the first step of the urea cycle in vivo. Female C57BL/6JRj mice treated with a glucagon receptor antagonist (GRA), glucagon receptor knockout (Gcgr-/-) mice, and wild-type (Gcgr+/+) littermates received an intraperitoneal injection of N-carbamoyl glutamate (Car; a stable variant of NAG), l-citrulline (Cit), Car and Cit (Car + Cit), or PBS. In separate experiments, Gcgr-/- and Gcgr+/+ mice were administered N-carbamoyl glutamate and l-citrulline (wCar + wCit) in the drinking water for 8 wk. Car, Cit, and Car + Cit significantly (P < 0.05) increased plasma urea concentrations, independently of pharmacological and genetic disruption of glucagon receptor signaling (P = 0.9). Car increased blood glucose concentrations equally in GRA- and vehicle-treated mice (P = 0.9), whereas the increase upon Car + Cit was impaired in GRA-treated mice (P = 0.008). Blood glucose concentrations remained unchanged in Gcgr-/- mice upon Car (P = 0.2) and Car + Cit (P = 0.9). Eight weeks administration of wCar + wCit did not change blood glucose (P > 0.2), plasma amino acid (P > 0.4), and urea concentrations (P > 0.3) or the area of glucagon-positive cells (P > 0.3) in Gcgr-/- and Gcgr+/+ mice. Our data suggest that glucagon-mediated activation of ureagenesis is not required when NAGS activity and/or NAG levels are sufficient to activate the first step of the urea cycle.NEW & NOTEWORTHY Hepatic ureagenesis is essential in amino acid metabolism and is importantly regulated by glucagon, but the exact mechanism is unclear. With the aim to identify the steps whereby glucagon both acutely and chronically regulates ureagenesis, we here show, contrary to our hypothesis, that glucagon receptor-mediated activation of ureagenesis is not required when N-acetylglutamate synthase activity and/or N-acetylglutamate levels are sufficient to activate the first step of the urea cycle in vivo.
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Affiliation(s)
- Katrine D Galsgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Pedersen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Endocrinology and Nephrology, Nordsjaellands Hospital Hilleroed, Hilleroed, Denmark
| | - Sasha A S Kjeldsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marie Winther-Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Elena Stojanovska
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hendrik Vilstrup
- Department of Hepatology and Gastroenterology, Aarhus University Hospital, Aarhus, Denmark
| | - Cathrine Ørskov
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai J Wewer Albrechtsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
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46
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Gilon P. The Role of α-Cells in Islet Function and Glucose Homeostasis in Health and Type 2 Diabetes. J Mol Biol 2020; 432:1367-1394. [PMID: 31954131 DOI: 10.1016/j.jmb.2020.01.004] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2019] [Revised: 12/23/2019] [Accepted: 01/06/2020] [Indexed: 01/09/2023]
Abstract
Pancreatic α-cells are the major source of glucagon, a hormone that counteracts the hypoglycemic action of insulin and strongly contributes to the correction of acute hypoglycemia. The mechanisms by which glucose controls glucagon secretion are hotly debated, and it is still unclear to what extent this control results from a direct action of glucose on α-cells or is indirectly mediated by β- and/or δ-cells. Besides its hyperglycemic action, glucagon has many other effects, in particular on lipid and amino acid metabolism. Counterintuitively, glucagon seems also required for an optimal insulin secretion in response to glucose by acting on its cognate receptor and, even more importantly, on GLP-1 receptors. Patients with diabetes mellitus display two main alterations of glucagon secretion: a relative hyperglucagonemia that aggravates hyperglycemia, and an impaired glucagon response to hypoglycemia. Under metabolic stress states, such as diabetes, pancreatic α-cells also secrete GLP-1, a glucose-lowering hormone, whereas the gut can produce glucagon. The contribution of extrapancreatic glucagon to the abnormal glucose homeostasis is unclear. Here, I review the possible mechanisms of control of glucagon secretion and the role of α-cells on islet function in healthy state. I discuss the possible causes of the abnormal glucagonemia in diabetes, with particular emphasis on type 2 diabetes, and I briefly comment the current antidiabetic therapies affecting α-cells.
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Affiliation(s)
- Patrick Gilon
- Université Catholique de Louvain, Institute of Experimental and Clinical Research, Pole of Endocrinology, Diabetes and Nutrition, Avenue Hippocrate 55 (B1.55.06), Brussels, B-1200, Belgium.
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47
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Lobato CB, Pereira SS, Guimarães M, Hartmann B, Wewer Albrechtsen NJ, Hilsted L, Holst JJ, Nora M, Monteiro MP. A Potential Role for Endogenous Glucagon in Preventing Post-Bariatric Hypoglycemia. Front Endocrinol (Lausanne) 2020; 11:608248. [PMID: 33424773 PMCID: PMC7793799 DOI: 10.3389/fendo.2020.608248] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/19/2020] [Accepted: 10/22/2020] [Indexed: 01/03/2023] Open
Abstract
Obesity and obesity-related diseases are major public health concerns that have been exponentially growing in the last decades. Bariatric surgery is an effective long-term treatment to achieve weight loss and obesity comorbidity remission. Post-bariatric hypoglycemia (PBH) is a late complication of bariatric surgery most commonly reported after Roux-en-Y gastric bypass (RYGB). PBH is the end result of postprandial hyperinsulinemia but additional endocrine mechanisms involved are still under debate. Our aim was to characterize entero-pancreatic hormone dynamics associated with postprandial hypoglycemia after RYGB. Individuals previously submitted to RYGB (N=23) in a single tertiary hospital presenting PBH symptoms (Sym, n=14) and asymptomatic weight-matched controls (Asy, n=9) were enrolled. Participants underwent a mixed-meal tolerance test (MMTT) to assess glucose, total amino acids (total AA), insulin, C-peptide, glucagon, glucose-dependent insulinotropic polypeptide (GIP), glucagon-like peptide-1 (GLP-1), and neurotensin (NT). We found that hypoglycemia during the MMTT was equally frequent in Sym and Asy groups (p=1.000). Re-grouped according to glucose nadir during the MMTT (Hypo n=11 vs NoHypo n=12; nadir <3.05 mmol/l vs ≥3.05 mmol/l), subjects presented no differences in anthropometric (BMI: p=0.527) or metabolic features (HbA1c: p=0.358), yet distinct meal-elicited hormone dynamics were identified. Postprandial glucose excursion and peak glucose levels were similar (p>0.05), despite distinct late glycemic outcomes (t=60 min and t=90 min: p<0.01), with overall greater glycemic variability in Hypo group (minimum-to-maximum glucose ratio: p<0.001). Hypo group meal-triggered hormone profile was characterized by lower early glucagon (t=15 min: p<0.01) and higher insulin (t=30 min: p<0.05, t=45 min: p<0.001), C-peptide (t=30 min: p<0.01, t=45 min: p<0.001, t=60 min: p<0.05), and GLP-1 (t=45 min: p<0.05) levels. Hyperinsulinemia was an independent risk factor for hypoglycemia (p<0.05). After adjusting for hyperinsulinemia, early glucagon correlated with glycemic nadir (p<0.01), and prevented postprandial hypoglycemia (p<0.05). A higher insulin to glucagon balance in Hypo was observed (p<0.05). No differences were observed in total AA, GIP or NT excursions (p>0.05). In sum, after RYGB, postprandial hyperinsulinemia is key in triggering PBH, but a parallel and earlier rise in endogenous glucagon might sustain the inter-individual variability in glycemic outcome beyond the effect of hyperinsulinism, advocating a potential pivotal role for glucagon in preventing hyperinsulinemic hypoglycemia.
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Affiliation(s)
- Carolina B. Lobato
- Endocrine, Cardiovascular & Metabolic Research, Unit for Multidisciplinary Research in Biomedicine (UMIB), University of Porto, Porto, Portugal
- Department of Anatomy, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
| | - Sofia S. Pereira
- Endocrine, Cardiovascular & Metabolic Research, Unit for Multidisciplinary Research in Biomedicine (UMIB), University of Porto, Porto, Portugal
- Department of Anatomy, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
- Instituto de Investigação e Inovação em Saúde (I3S), Universidade do Porto, Porto, Portugal
- Institute of Molecular Pathology and Immunology of the University of Porto (IPATIMUP), Porto, Portugal
| | - Marta Guimarães
- Endocrine, Cardiovascular & Metabolic Research, Unit for Multidisciplinary Research in Biomedicine (UMIB), University of Porto, Porto, Portugal
- Department of Anatomy, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
- Department of General Surgery, Centro Hospitalar de Entre o Douro e Vouga, Santa Maria da Feira, Portugal
| | - Bolette Hartmann
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Nicolai J. Wewer Albrechtsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Linda Hilsted
- Department of Clinical Biochemistry, Rigshospitalet, University of Copenhagen, Copenhagen, Denmark
| | - Jens J. Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mário Nora
- Endocrine, Cardiovascular & Metabolic Research, Unit for Multidisciplinary Research in Biomedicine (UMIB), University of Porto, Porto, Portugal
- Department of General Surgery, Centro Hospitalar de Entre o Douro e Vouga, Santa Maria da Feira, Portugal
| | - Mariana P. Monteiro
- Endocrine, Cardiovascular & Metabolic Research, Unit for Multidisciplinary Research in Biomedicine (UMIB), University of Porto, Porto, Portugal
- Department of Anatomy, Institute of Biomedical Sciences Abel Salazar (ICBAS), University of Porto, Porto, Portugal
- *Correspondence: Mariana P. Monteiro,
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48
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Godoy-Matos AF, Silva Júnior WS, Valerio CM. NAFLD as a continuum: from obesity to metabolic syndrome and diabetes. Diabetol Metab Syndr 2020; 12:60. [PMID: 32684985 PMCID: PMC7359287 DOI: 10.1186/s13098-020-00570-y] [Citation(s) in RCA: 288] [Impact Index Per Article: 72.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/31/2020] [Accepted: 07/08/2020] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND The prevalence of non-alcoholic fatty liver disease (NAFLD) has been increasing rapidly. It is nowadays recognized as the most frequent liver disease, affecting a quarter of global population and regularly coexisting with metabolic disorders such as type 2 diabetes, hypertension, obesity, and cardiovascular disease. In a more simplistic view, NAFLD could be defined as an increase in liver fat content, in the absence of secondary cause of steatosis. In fact, the clinical onset of the disease is a much more complex process, closely related to insulin resistance, limited expandability and dysfunctionality of adipose tissue. A fatty liver is a main driver for a new recognized liver-pancreatic α-cell axis and increased glucagon, contributing to diabetes pathophysiology. MAIN TEXT This review will focus on the clinical and pathophysiological connections between NAFLD, insulin resistance and type 2 diabetes. We reviewed non-invasive methods and several scoring systems for estimative of steatosis and fibrosis, proposing a multistep process for NAFLD evaluation. We will also discuss treatment options with a more comprehensive view, focusing on the current available therapies for obesity and/or type 2 diabetes that impact each stage of NAFLD. CONCLUSION The proper understanding of NAFLD spectrum-as a continuum from obesity to metabolic syndrome and diabetes-may contribute to the early identification and for establishment of targeted treatment.
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Affiliation(s)
- Amélio F. Godoy-Matos
- Metabolism Department, Instituto Estadual de Diabetes e Endocrinologia (IEDE), Pontifical Catholic University of Rio de Janeiro (PUC-Rio), Rio de Janeiro, RJ CEP 20211-340 Brazil
| | - Wellington S. Silva Júnior
- Endocrinology Discipline, Faculty of Medicine, Center of Natural, Human, Health, and Technology Sciences, Federal University of Maranhão (UFMA), Pinheiro, MA CEP 65200-000 Brazil
| | - Cynthia M. Valerio
- Metabolism Department, Instituto Estadual de Diabetes e Endocrinologia (IEDE), Pontifical Catholic University of Rio de Janeiro (PUC-Rio), Rio de Janeiro, RJ CEP 20211-340 Brazil
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49
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Jarak I, Pereira SS, Carvalho RA, Oliveira PF, Alves MG, Guimarães M, Wewer Albrechtsen NJ, Holst JJ, Nora M, Monteiro MP. Gastric Bypass with Different Biliopancreatic Limb Lengths Results in Similar Post-absorptive Metabolomics Profiles. Obes Surg 2019; 30:1068-1078. [DOI: 10.1007/s11695-019-04294-5] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
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50
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Noguchi GM, Huising MO. Integrating the inputs that shape pancreatic islet hormone release. Nat Metab 2019; 1:1189-1201. [PMID: 32694675 PMCID: PMC7378277 DOI: 10.1038/s42255-019-0148-2] [Citation(s) in RCA: 68] [Impact Index Per Article: 13.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 11/07/2019] [Indexed: 02/06/2023]
Abstract
The pancreatic islet is a complex mini organ composed of a variety of endocrine cells and their support cells, which together tightly control blood glucose homeostasis. Changes in glucose concentration are commonly regarded as the chief signal controlling insulin-secreting beta cells, glucagon-secreting alpha cells and somatostatin-secreting delta cells. However, each of these cell types is highly responsive to a multitude of endocrine, paracrine, nutritional and neural inputs, which collectively shape the final endocrine output of the islet. Here, we review the principal inputs for each islet-cell type and the physiological circumstances in which these signals arise, through the prism of the insights generated by the transcriptomes of each of the major endocrine-cell types. A comprehensive integration of the factors that influence blood glucose homeostasis is essential to successfully improve therapeutic strategies for better diabetes management.
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Affiliation(s)
- Glyn M Noguchi
- Department of Neurobiology, Physiology & Behavior, College of Biological Sciences, University of California, Davis, Davis, CA, USA
| | - Mark O Huising
- Department of Neurobiology, Physiology & Behavior, College of Biological Sciences, University of California, Davis, Davis, CA, USA.
- Department of Physiology & Membrane Biology, School of Medicine, University of California, Davis, Davis, CA, USA.
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