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Honka H, Gastaldelli A, Pezzica S, Peterson R, DeFronzo R, Salehi M. Differential effect of endogenous glucagon-like peptide-1 on prandial glucose counterregulatory response to hypoglycaemia in humans with and without bariatric surgery. Diabetes Obes Metab 2024; 26:2476-2486. [PMID: 38558527 PMCID: PMC11078606 DOI: 10.1111/dom.15570] [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: 01/18/2024] [Revised: 02/25/2024] [Accepted: 03/06/2024] [Indexed: 04/04/2024]
Abstract
AIM To determine the effect of endogenous glucagon-like peptide 1 (GLP-1) on prandial counterregulatory response to hypoglycaemia after gastric bypass (GB). MATERIALS AND METHODS Glucose fluxes, and islet-cell and gut hormone responses before and after mixed-meal ingestion, were compared during a hyperinsulinaemic-hypoglycaemic (~3.2 mmol/L) clamp with and without a GLP-1 receptor (GLP-1R) antagonist exendin-(9-39) infusion in non-diabetic patients who had previously undergone GB compared to matched participants who had previously undergone sleeve gastrectomy (SG) and non-surgical controls. RESULTS Exendin-(9-39) infusion raised prandial endogenous glucose production (EGP) response to insulin-induced hypoglycaemia in the GB group but had no consistent effect on EGP response among the SG group or non-surgical controls (p < 0.05 for interaction). The rates of systemic appearance of ingested glucose or prandial glucose utilization did not differ among the three groups or between studies with and without exendin-(9-39) infusion. Blockade of GLP-1R had no effect on insulin secretion or insulin action but enhanced prandial glucagon in all three groups. CONCLUSIONS These results indicate that impaired post-meal glucose counterregulatory response to hypoglycaemia after GB is partly mediated by endogenous GLP-1, highlighting a novel pathogenic mechanism of GLP-1 in developing hypoglycaemia in this population.
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Affiliation(s)
- Henri Honka
- Division of Diabetes, University of Texas Health Science Center, San Antonio, TX
| | - Amalia Gastaldelli
- Cardiometabolic Risk Unit, Institute of Clinical Physiology-National Research Council, Pisa, Italy
| | - Samantha Pezzica
- Cardiometabolic Risk Unit, Institute of Clinical Physiology-National Research Council, Pisa, Italy
| | - Richard Peterson
- Department of Surgery, University of Texas Health Science Center, San Antonio, TX
| | - Ralph DeFronzo
- Division of Diabetes, University of Texas Health Science Center, San Antonio, TX
| | - Marzieh Salehi
- Division of Diabetes, University of Texas Health Science Center, San Antonio, TX
- South Texas Veteran Health Care System, Audie Murphy Hospital, San Antonio, TX
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Honka H, Gastaldelli A, Pezzica S, Peterson R, DeFronzo R, Salehi M. Endogenous glucagon-like peptide 1 diminishes prandial glucose counterregulatory response to hypoglycemia after gastric bypass surgery. MEDRXIV : THE PREPRINT SERVER FOR HEALTH SCIENCES 2023:2023.09.20.23295840. [PMID: 37790563 PMCID: PMC10543055 DOI: 10.1101/2023.09.20.23295840] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/05/2023]
Abstract
We have previously shown that prandial endogenous glucose production (EGP) during insulin-induced hypoglycemia is smaller in non-diabetic subjects with gastric bypass (GB), where prandial glucagon-like peptide 1 (GLP-1) concentrations are 5-10 times higher than those in non-operated controls. Here, we sought to determine the effect of endogenous GLP-1 on prandial counterregulatory response to hypoglycemia after GB. Glucose fluxes, and islet-cell and gut hormone responses before and after mixed-meal ingestion were compared during a hyperinsulinemic hypoglycemic (~3.2 mmol/l) clamp with and without a GLP-1 receptor (GLP-1R) antagonist exendin-(9-39) (Ex-9) in non-diabetic subjects with prior GB compared to matched subjects with SG and non-surgical controls. In this setting, GLP-1R blockade had no effect on insulin secretion or insulin action, whereas prandial glucagon was enhanced in all 3 groups. Ex-9 infusion raised prandial EGP response to hypoglycemia in every GB subject but had no consistent effects on EGP among subjects with SG or non-operated controls (P < 0.05 for interaction). These results indicate that impaired post-meal glucose counterregulatory response to hypoglycemia after GB is partly mediated by endogenous GLP-1, highlighting a novel mechanism of action of GLP-1R antagonists for the treatment of prandial hypoglycemia in this population.
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Huang LY, Liu CH, Chen FY, Kuo CH, Pitrone P, Liu JS. Aging Affects Insulin Resistance, Insulin Secretion, and Glucose Effectiveness in Subjects with Normal Blood Glucose and Body Weight. Diagnostics (Basel) 2023; 13:2158. [PMID: 37443552 DOI: 10.3390/diagnostics13132158] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/26/2023] [Revised: 06/18/2023] [Accepted: 06/21/2023] [Indexed: 07/15/2023] Open
Abstract
AIM Several studies have demonstrated that factors including diabetes, including insulin resistance (IR), glucose effectiveness (GE), and the first and second phase of insulin secretion (FPIS, SPIS) could easily be calculated using basic characteristics and biochemistry profiles. Aging is accompanied by deteriorations of insulin resistance (IR) and insulin secretion. However, little is known about the roles of aging in the different phases of insulin secretion (ISEC), i.e., the first and second phase of insulin secretion (FPIS, SPIS), and glucose effectiveness (GE). METHODS In total, 169 individuals (43 men and 126 women) recruited from the data bank of the Meei-Jaw (MJ) Health Screening Center and Cardinal Tien Hospital Data Access Center between 1999 and 2008, with a similar fasting plasma glucose (FPG: 90 mg/dL) and BMI (men: 23 kg/m2, women 22 kg/m2) were enrolled. The IR, FPIS, SPIS, and GE were estimated using our previously developed equations shown below. Pearson correlation analysis was conducted to assess the correlations between age and four diabetes factors (DFs: IR, FPIS, SPIS, and GE). The equations that are used to calculate the DF in the present study were built and published by our group. RESULTS The age of the participants ranged from 18 to 78 years. Men had higher FPIS but lower HDL-C levels than women (2.067 ± 0.159, 1.950 ± 0.186 μU/min and 1.130 ± 0.306, 1.348 ± 0.357 mmol/dl, accordingly). The results of the Pearson correlation revealed that age was negatively related to the IR and GE in both genders (IR: r = -0.39, p < 0.001 for men, r = -0.24, p < 0.003 for women; GE: r = 0.66, p < 0.001 for men, r = 0.78, p < 0.001 for women). At the same time, the FPIS was also only found to be negatively correlated with age in females (r = -0.238, p = 0.003), but there was no difference in the SPIS and age among both genders. CONCLUSIONS We have found that in Chinese subjects with a normal FPG level (90 mg/dL) and body mass index (men: 23 kg/m2, women: 22: kg/m2), age is negatively related to the IR and GE among both genders. Only the FPIS was found to be negatively related to age in women. The tightness of their relationships, from the highest to the lowest, are GE, FPIS, and IR. These results should be interpreted with caution because of the small sample size.
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Affiliation(s)
- Li-Ying Huang
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Fu Jen Catholic University Hospital, New Taipei 24352, Taiwan
| | - Chi-Hao Liu
- Division of Nephrology, Department of Medicine, Kaohsiung Armed Forces General Hospital, Kaohsiung 80284, Taiwan
| | - Fang-Yu Chen
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Fu Jen Catholic University Hospital, New Taipei 24352, Taiwan
| | - Chun-Heng Kuo
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Fu Jen Catholic University Hospital, New Taipei 24352, Taiwan
| | - Pietro Pitrone
- Department of Biomedical and Dental Sciences and Morpho-Functional Imaging, University of Messina, 98158 Messina, Italy
| | - Jhih-Syuan Liu
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Tri-Service General Hospital, National Defense Medical Center, Taipei 11490, Taiwan
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Abdulla H, Phillips B, Wilkinson D, Gates A, Limb M, Jandova T, Bass J, Lewis J, Williams J, Smith K, Idris I, Atherton P. Effects of GLP-1 Infusion Upon Whole-body Glucose Uptake and Skeletal Muscle Perfusion During Fed-state in Older Men. J Clin Endocrinol Metab 2023; 108:971-978. [PMID: 36260533 PMCID: PMC9999358 DOI: 10.1210/clinem/dgac613] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 10/05/2022] [Indexed: 11/19/2022]
Abstract
INTRODUCTION Ageing skeletal muscles become both insulin resistant and atrophic. The hormone glucagon-like peptide 1 (GLP-1) facilitates postprandial glucose uptake as well as augmenting muscle perfusion, independent of insulin action. We thus hypothesized exogenous GLP-1 infusions would enhance muscle perfusion and positively affect glucose metabolism during fed-state clamps in older people. METHODS Eight men (71 ± 1 years) were studied in a randomized crossover trial. Basal blood samples were taken before postprandial (fed-state) insulin and glucose clamps, accompanied by amino acid infusions, for 3 hours. Reflecting this, following insertions of peripheral and femoral vessels cannulae and baseline measurements, peripheral IV infusions of octreotide, insulin (Actrapid), 20% glucose, and mixed amino acids; Vamin 14-EF with or without a femoral arterial GLP-1 infusion were started. GLP-1, insulin, and C-peptide were measured by ELISA. Muscle microvascular blood flow was assessed via contrast enhanced ultrasound. Whole-body glucose handling was assayed by assessing glucose infusion rate parameters. RESULTS Skeletal muscle microvascular blood flow significantly increased in response to GLP-1 vs feeding alone (5.0 ± 2.1 vs 1.9 ± 0.7 fold-change from basal, respectively; P = 0.008), while also increasing whole-body glucose uptake (area under the curve 16.9 ± 1.7 vs 11.4 ± 1.8 mg/kg-1/180 minutes-1, P = 0.02 ± GLP, respectively). CONCLUSIONS The beneficial effects of GLP-1 on whole-body glycemic control are evident with insulin clamped at fed-state levels. GLP-1 further enhances the effects of insulin on whole-body glucose uptake in older men, underlining its role as a therapeutic target. The effects of GLP-1 in enhancing microvascular flow likely also affects other glucose-regulatory organs, reflected by greater whole-body glucose uptake.
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Affiliation(s)
- Haitham Abdulla
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Centre of Metabolism, Ageing and Physiology (COMAP), Academic Unit of Injury, Recovery and Inflammation Sciences (IRIS), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
- Diabetes and Endocrinology Centre, University Hospitals Birmingham NHS Foundation Trust, Heartlands Hospitals, Birmingham B9 5SS, UK
| | - Bethan Phillips
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Centre of Metabolism, Ageing and Physiology (COMAP), Academic Unit of Injury, Recovery and Inflammation Sciences (IRIS), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
- NIHR, Nottingham BRC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Daniel Wilkinson
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Centre of Metabolism, Ageing and Physiology (COMAP), Academic Unit of Injury, Recovery and Inflammation Sciences (IRIS), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
- NIHR, Nottingham BRC, University of Nottingham, Nottingham NG7 2UH, UK
| | - Amanda Gates
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Centre of Metabolism, Ageing and Physiology (COMAP), Academic Unit of Injury, Recovery and Inflammation Sciences (IRIS), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
| | - Marie Limb
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Centre of Metabolism, Ageing and Physiology (COMAP), Academic Unit of Injury, Recovery and Inflammation Sciences (IRIS), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
| | - Tereza Jandova
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Centre of Metabolism, Ageing and Physiology (COMAP), Academic Unit of Injury, Recovery and Inflammation Sciences (IRIS), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
- Department of Physiology and Biochemistry, Faculty of Physical Education and Sport, Charles University, Prague 6, Czech Republic
| | - Joseph Bass
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Centre of Metabolism, Ageing and Physiology (COMAP), Academic Unit of Injury, Recovery and Inflammation Sciences (IRIS), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
| | - Johnathan Lewis
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Centre of Metabolism, Ageing and Physiology (COMAP), Academic Unit of Injury, Recovery and Inflammation Sciences (IRIS), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
| | - John Williams
- MRC-Versus Arthritis Centre for Musculoskeletal Ageing Research, Centre of Metabolism, Ageing and Physiology (COMAP), Academic Unit of Injury, Recovery and Inflammation Sciences (IRIS), School of Medicine, University of Nottingham, Royal Derby Hospital, Derby DE22 3DT, UK
- NIHR, Nottingham BRC, University of Nottingham, Nottingham NG7 2UH, UK
- Department of Anaesthesia, University Hospitals Derby and Burton NHS Foundation Trust, Derby DE22 3NE, UK
| | | | | | - Philip Atherton
- Correspondence: Philip J. Atherton, PhD, University of Nottingham School of Medicine, Royal Derby Hospital, Uttoxeter Road, Derby, DE22 3DT, UK.
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Kohlenberg JD, Laurenti MC, Egan AM, Wismayer DS, Bailey KR, Cobelli C, Man CD, Vella A. Differential contribution of alpha and beta cell dysfunction to impaired fasting glucose and impaired glucose tolerance. Diabetologia 2023; 66:201-212. [PMID: 36112169 PMCID: PMC9742343 DOI: 10.1007/s00125-022-05794-3] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/18/2022] [Accepted: 08/02/2022] [Indexed: 12/14/2022]
Abstract
AIMS/HYPOTHESIS People with isolated impaired fasting glucose (IFG) have normal beta cell function. We hypothesised that an increased glucose threshold for beta cell secretion explains IFG. METHODS We used graded glucose infusion to examine the relationship of insulin secretion rate (ISR) and glucagon secretion rate (GSR) with rising glucose. We studied 39 non-diabetic individuals (53 ± 2 years, BMI 30 ± 1 kg/m2), categorised by fasting glucose and glucose tolerance status. After an overnight fast, a variable insulin infusion was used to maintain glucose at ~4.44 mmol/l (07:00 to 08:30 hours). At 09:00 hours, graded glucose infusion commenced at 1 mg kg-1 min-1 and doubled every 60 min until 13:00 hours. GSR and ISR were calculated by nonparametric deconvolution from concentrations of glucagon and C-peptide, respectively. RESULTS The relationship of ISR with glucose was linear and the threshold for insulin secretion in isolated IFG did not differ from that in people with normal fasting glucose and normal glucose tolerance. GSR exhibited a single-exponential relationship with glucose that could be characterised by G50, the change in glucose necessary to suppress GSR by 50%. G50 was increased in IFG compared with normal fasting glucose regardless of the presence of impaired or normal glucose tolerance. CONCLUSIONS/INTERPRETATION These data show that, in non-diabetic humans, alpha cell dysfunction contributes to the pathogenesis of IFG independently of defects in insulin secretion. We also describe a new index that quantifies the suppression of glucagon secretion by glucose.
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Affiliation(s)
- Jacob D Kohlenberg
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Marcello C Laurenti
- Biomedical Engineering and Physiology Graduate Program, Mayo Clinic Graduate School of Biomedical Sciences, Rochester, MN, USA
| | - Aoife M Egan
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Daniel Schembri Wismayer
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, MN, USA
| | - Kent R Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, MN, USA
| | - Claudio Cobelli
- Department of Women's and Children's Health, University of Padova, Padova, Italy
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Adrian Vella
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, MN, USA.
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Nauck MA, D‘Alessio DA. Tirzepatide, a dual GIP/GLP-1 receptor co-agonist for the treatment of type 2 diabetes with unmatched effectiveness regrading glycaemic control and body weight reduction. Cardiovasc Diabetol 2022; 21:169. [PMID: 36050763 PMCID: PMC9438179 DOI: 10.1186/s12933-022-01604-7] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/19/2022] [Indexed: 11/29/2022] Open
Abstract
Tirzepatide is the first dual GIP/GLP-1 receptor co-agonist approved for the treatment of type 2 diabetes in the USA, Europe, and the UAE. Tirzepatide is an acylated peptide engineered to activate the GIP and GLP-1 receptors, key mediators of insulin secretion that are also expressed in regions of the brain that regulate food intake. Five clinical trials in type 2-diabetic subjects (SURPASS 1–5) have shown that tirzepatide at 5–15 mg per week reduces both HbA1c (1.24 to 2.58%) and body weight (5.4–11.7 kg) by amounts unprecedented for a single agent. A sizable proportion of patients (23.0 to 62.4%) reached an HbA1c of < 5.7% (which is the upper limit of the normal range indicating normoglycaemia), and 20.7 to 68.4% lost more than 10% of their baseline body weight. Tirzepatide was significantly more effective in reducing HbA1c and body weight than the selective GLP-1 RA semaglutide (1.0 mg per week), and titrated basal insulin. Adverse events related to tirzepatide were similar to what has been reported for selective GLP-1RA, mainly nausea, vomiting, diarrhoea, and constipation, that were more common at higher doses. Cardiovascular events have been adjudicated across the whole study program, and MACE-4 (nonfatal myocardial infarction, non-fatal stroke, cardiovascular death and hospital admission for angina) events tended to be reduced over up to a 2 year-period, albeit with low numbers of events. For none of the cardiovascular events analysed (MACE-4, or its components) was a hazard ratio > 1.0 vs. pooled comparators found in a meta-analysis covering the whole clinical trial program, and the upper bounds of the confidence intervals for MACE were < 1.3, fulfilling conventional definitions of cardiovascular safety. Tirzepatide was found to improve insulin sensitivity and insulin secretory responses to a greater extent than semaglutide, and this was associated with lower prandial insulin and glucagon concentrations. Both drugs caused similar reductions in appetite, although tirzepatide caused greater weight loss. While the clinical effects of tirzepatide have been very encouraging, important questions remain as to the mechanism of action. While GIP reduces food intake and body weight in rodents, these effects have not been demonstrated in humans. Moreover, it remains to be shown that GIPR agonism can improve insulin secretion in type 2 diabetic patients who have been noted in previous studies to be unresponsive to GIP. Certainly, the apparent advantage of tirzepatide, a dual incretin agonist, over GLP-1RA will spark renewed interest in the therapeutic potential of GIP in type 2 diabetes, obesity and related co-morbidities.
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Adams JD, Egan AM, Laurenti MC, Schembri Wismayer D, Bailey KR, Cobelli C, Dalla Man C, Vella A. The Effect of Diabetes-Associated Variation in TCF7L2 on Postprandial Glucose Metabolism When Glucagon and Insulin Concentrations Are Matched. Metab Syndr Relat Disord 2022; 20:329-335. [PMID: 35442800 PMCID: PMC9419949 DOI: 10.1089/met.2021.0136] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Background: The rs7903146 variant in the TCF7L2 gene is associated with defects in postprandial insulin and glucagon secretion and increased risk of type 2 diabetes. However, it is unclear if this variant has effects on glucose metabolism that are independent of islet function. Methods: We studied 54 nondiabetic subjects on two occasions where endogenous hormone secretion was inhibited by somatostatin. Twenty-nine subjects were homozygous for the diabetes-associated allele (TT) and 25 for the diabetes-protective allele (CC) at rs7903146, but otherwise matched for anthropometric characteristics. On 1 day, glucagon infused at a rate of 0.65 ng/kg/min, and at 0 min prevented a fall in glucagon (nonsuppressed day). On the contrary, infusion commenced at 120 min to create a transient fall in glucagon (suppressed day). Subjects received glucose (labeled with [3-3H]-glucose) infused to mimic the systemic appearance of oral glucose. Insulin was infused to mimic a prandial insulin response. Endogenous glucose production (EGP) was measured using the tracer dilution technique. Results: Lack of glucagon suppression increased postchallenge glucose concentrations and impaired EGP suppression. However, in the presence of matched insulin and glucagon concentrations, genetic variation in TCF7L2 did not alter glucose metabolism. Conclusion: These data suggest that genetic variation in TCF7L2 alters glucose metabolism through changes in islet hormone secretion.
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Affiliation(s)
- Jon D Adams
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Aoife M Egan
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Marcello C Laurenti
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Daniel Schembri Wismayer
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
| | - Kent R Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota, USA
| | - Claudio Cobelli
- Department of Woman and Child's Health and University of Padova, Padova, Italy
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Adrian Vella
- Division of Endocrinology, Diabetes and Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota, USA
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Jonik S, Marchel M, Grabowski M, Opolski G, Mazurek T. Gastrointestinal Incretins-Glucose-Dependent Insulinotropic Polypeptide (GIP) and Glucagon-like Peptide-1 (GLP-1) beyond Pleiotropic Physiological Effects Are Involved in Pathophysiology of Atherosclerosis and Coronary Artery Disease-State of the Art. BIOLOGY 2022; 11:biology11020288. [PMID: 35205155 PMCID: PMC8869592 DOI: 10.3390/biology11020288] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 02/03/2022] [Accepted: 02/07/2022] [Indexed: 02/06/2023]
Abstract
Simple Summary The presented manuscript contains the most current and extensive summary of the role of the most predominant gastrointestinal hormones—GIP and GLP-1 in the pathophysiology of atherosclerosis and coronary artery disease both in animals and humans. We have described GIP and GLP-1 as (1) expressed in many human tissues, (2) emphasized relationship between GIP and GLP-1 and inflammation, (3) highlighted importance of GIP and GLP-1-dependent pathways in atherosclerosis and coronary artery disease and (4) proved that GIP and GLP-1 could be used as markers of incidence, clinical course and recurrence of coronary artery disease, and related to extent and severity of atherosclerosis and myocardial ischemia. Our initial review may state a cornerstone for the future, however, there are still many unknowns and understatements on this topic. Due to the widespread growing interest for the potential use of incretins in cardiovascular diseases, we think that further research in this direction is desirable. For the future, we would like to recognize GIP and GLP-1 as widely implemented into clinical practice as new biomarkers of atherosclerosis and coronary artery disease. Abstract Coronary artery disease (CAD), which is the manifestation of atherosclerosis in coronary arteries, is the most common single cause of death and is responsible for disabilities of millions of people worldwide. Despite numerous dedicated clinical studies and an enormous effort to develop diagnostic and therapeutic methods, coronary atherosclerosis remains one of the most serious medical problems of the modern world. Hence, new markers are still being sought to identify and manage CAD optimally. Trying to face this problem, we have raised the question of the most predominant gastrointestinal hormones; glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1), mainly involved in carbohydrates disorders, could be also used as new markers of incidence, clinical course, and recurrence of CAD and are related to extent and severity of atherosclerosis and myocardial ischemia. We describe GIP and GLP-1 as expressed in many animal and human tissues, known to be connected to inflammation and related to enormous noncardiac and cardiovascular (CV) diseases. In animals, GIP and GLP-1 improve endothelial function and lead to reduced atherosclerotic plaque macrophage infiltration and stabilize atherosclerotic lesions by directly blocking monocyte migration. Moreover, in humans, GIPR activation induces the pro-atherosclerotic factors ET-1 (endothelin-1) and OPN (osteopontin) but also has anti-atherosclerotic effects through secretion of NO (nitric oxide). Furthermore, four large clinical trials showed a significant reduction in composite of CV death, MI, and stroke in long-term follow-up using GLP-1 analogs for DM 2 patients: liraglutide in LEADER, semaglutide in SUSTAIN-6, dulaglutide in REWIND and albiglutide in HARMONY. However, very little is known about GIP metabolism in the acute phase of myocardial ischemia or for stable patients with CAD, which constitutes a direction for future research. This review aims to comprehensively discuss the impact of GIP and GLP-1 on atherosclerosis and CAD and its potential therapeutic implications.
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Adams JD, Egan AM, Laurenti MC, Schembri Wismayer D, Bailey KR, Cobelli C, Dalla Man C, Vella A. Insulin secretion and action and the response of endogenous glucose production to a lack of glucagon suppression in nondiabetic subjects. Am J Physiol Endocrinol Metab 2021; 321:E728-E736. [PMID: 34658253 PMCID: PMC8782666 DOI: 10.1152/ajpendo.00284.2021] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Type 2 diabetes is a disease characterized by impaired insulin secretion and defective glucagon suppression in the postprandial period. We examined the effect of impaired glucagon suppression on glucose concentrations and endogenous glucose production (EGP) at different degrees of insulin secretory impairment. The contribution of anthropometric characteristics, peripheral, and hepatic insulin action to this variability was also examined. To do so, we studied 54 nondiabetic subjects on two occasions in which endogenous hormone secretion was inhibited by somatostatin, with glucagon infused at a rate of 0.65 ng/kg/min, at 0 min to prevent a fall in glucagon (nonsuppressed day) or at 120 min to create a transient fall in glucagon (suppressed day). Subjects received glucose (labeled with [3-3H]-glucose) infused to mimic the systemic appearance of 50-g oral glucose. Insulin was infused to mimic a prandial insulin response in 18 subjects, another 18 received 80% of the dose, and the remaining 18 received 60%. EGP was measured using the tracer-dilution technique. Decreased prandial insulin resulted in greater % increase in peak glucose but not in integrated glucose concentrations attributable to nonsuppressed glucagon. The % change in integrated EGP was unaffected by insulin dose. Multivariate regression analysis, adjusted for age, sex, weight, and insulin dose, did not show a relationship between the EGP response to impaired suppression of glucagon and insulin action as measured at the time of screening by oral glucose tolerance. A similar analysis for hepatic insulin action also did not show a relationship with the EGP response. These data indicate that the effect of impaired glucagon suppression on EGP is independent of anthropometric characteristics and insulin action.NEW & NOTEWORTHY In prediabetes, anthropometric characteristics as well as insulin action do not alter the hepatic response to glucagon. The postprandial suppression or lack of suppression of glucagon secretion is an important factor governing postprandial glucose tolerance independent of insulin secretion.
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Affiliation(s)
- Jon D Adams
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
- Department of Health and Human Performance, College of Charleston, Charleston, South Carolina
| | - Aoife M Egan
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Marcello C Laurenti
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Daniel Schembri Wismayer
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Kent R Bailey
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota
| | - Claudio Cobelli
- Department of Woman and Child's Health, University of Padova, Padova, Italy
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
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Guerrero-Hreins E, Goldstone AP, Brown RM, Sumithran P. The therapeutic potential of GLP-1 analogues for stress-related eating and role of GLP-1 in stress, emotion and mood: a review. Prog Neuropsychopharmacol Biol Psychiatry 2021; 110:110303. [PMID: 33741445 DOI: 10.1016/j.pnpbp.2021.110303] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/22/2020] [Revised: 02/19/2021] [Accepted: 03/09/2021] [Indexed: 01/11/2023]
Abstract
Stress and low mood are powerful triggers for compulsive overeating, a maladaptive form of eating leading to negative physical and mental health consequences. Stress-vulnerable individuals, such as people with obesity, are particularly prone to overconsumption of high energy foods and may use it as a coping mechanism for general life stressors. Recent advances in the treatment of obesity and related co-morbidities have focused on the therapeutic potential of anorexigenic gut hormones, such as glucagon-like peptide 1 (GLP-1), which acts both peripherally and centrally to reduce energy intake. Besides its appetite suppressing effect, GLP-1 acts on areas of the brain involved in stress response and emotion regulation. However, the role of GLP-1 in emotion and stress regulation, and whether it is a viable treatment for stress-induced compulsive overeating, has yet to be established. A thorough review of the pre-clinical literature measuring markers of stress, anxiety and mood after GLP-1 exposure points to potential divergent effects based on temporality. Specifically, acute GLP-1 injection consistently stimulates the physiological stress response in rodents whereas long-term exposure indicates anxiolytic and anti-depressive benefits. However, the limited clinical evidence is not as clear cut. While prolonged GLP-1 analogue treatment in people with type 2 diabetes improved measures of mood and general psychological wellbeing, the mechanisms underlying this may be confounded by associated weight loss and improved blood glucose control. There is a paucity of longitudinal clinical literature on mechanistic pathways by which stress influences eating behavior and how centrally-acting gut hormones such as GLP-1, can modify these. (250).
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Affiliation(s)
- Eva Guerrero-Hreins
- The Florey Institute of Neuroscience and Mental Health, Mental Health Theme, Parkville, Melbourne, Australia; The Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia; PsychoNeuroEndocrinology Research Group, Centre for Neuropsychopharmacology, Division of Psychiatry, and Computational, Cognitive and Clinical Neuroimaging Laboratory, Department of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK
| | - Anthony P Goldstone
- PsychoNeuroEndocrinology Research Group, Centre for Neuropsychopharmacology, Division of Psychiatry, and Computational, Cognitive and Clinical Neuroimaging Laboratory, Department of Brain Sciences, Faculty of Medicine, Imperial College London, Hammersmith Hospital, London, UK
| | - Robyn M Brown
- The Florey Institute of Neuroscience and Mental Health, Mental Health Theme, Parkville, Melbourne, Australia; The Florey Department of Neuroscience and Mental Health, University of Melbourne, Parkville, Melbourne, Australia
| | - Priya Sumithran
- Department of Medicine (St Vincent's), University of Melbourne, Victoria, Australia; Dept. of Endocrinology, Austin Health, Victoria, Australia.
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11
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Potential physio-pathological effects of branched fatty acid esters of hydroxy fatty acids. Biochimie 2021; 182:13-22. [PMID: 33412159 DOI: 10.1016/j.biochi.2020.12.020] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2020] [Revised: 12/14/2020] [Accepted: 12/28/2020] [Indexed: 12/31/2022]
Abstract
Branched Fatty Acid Esters of Hydroxy Fatty Acids (FAHFAs) are a new endogenous lipid class with recently uncovered interesting biological effects and which have been detected in food of plant and animal origins. Some FAHFAs can improve glucose tolerance and insulin sensitivity, stimulate insulin secretion, and exert anti-inflammatory effects. Other beneficial health effects have also been suggested, in particular against some cancers. FAHFAs could therefore be a potential therapeutic target for the treatment of numerous metabolic disorders such as type II diabetes, hepatic steatosis, cardiovascular diseases and various cancers. Their recent discovery has generated a great interest in the field of human health. This short review aims at bringing together the information available to date in the literature concerning their chemical synthesis, biosynthesis and degradation pathways as well as their potential physio-pathological beneficial effects.
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12
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Laurenti MC, Vella A, Adams JD, Schembri Wismayer DJ, Egan AM, Dalla Man C. Assessment of individual and standardized glucagon kinetics in healthy humans. Am J Physiol Endocrinol Metab 2021; 320:E71-E77. [PMID: 33135460 PMCID: PMC8194411 DOI: 10.1152/ajpendo.00488.2020] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Impaired glucose tolerance arises out of impaired postprandial insulin secretion and delayed suppression of glucagon. These defects occur early and independently in the pathogenesis of prediabetes. Quantification of the contribution of α-cell dysfunction to glucose tolerance has been lacking because knowledge of glucagon kinetics in humans is limited. Therefore, in a series of experiments examining the interaction of glucagon suppression with insulin secretion we studied 51 nondiabetic subjects (age = 54 ± 13 yr, BMI = 28 ± 4 kg/m2). Glucose was infused to mimic the systemic appearance of an oral challenge. Somatostatin was used to inhibit endogenous hormone secretion. 120 min after the start of the experiment, glucagon was infused at 0.65 ng/kg/min. The rise in glucagon concentrations was used to estimate its kinetic parameters [volume of distribution (Vd), half-life (t1/2), and clearance rate (CL)]. A single-exponential model provided the best fit for the data, and individualized kinetic parameters were estimated: Vd = 8.2 ± 2.7 L, t1/2 = 4 ± 1.1 min, CL = 1.4 ± 0.33 L/min. Stepwise linear regression was used to correlate Vd with BMI and sex (R2adj = 0.44), whereas CL similarly correlated with lean body mass or BSA (both R2 = 0.28). This enabled the development of a population-based model using anthropometric characteristics to predict Vd and CL. These data demonstrate that it is feasible to derive glucagon kinetic parameters from anthropometric characteristics, thereby enabling quantitation of the rate of glucagon appearance in the systemic circulation in large populations.NEW & NOTEWORTHY State-of-the-art measurement of insulin secretion in humans is accomplished by deconvolution of peripheral C-peptide concentrations using population-derived parameters of C-peptide kinetics. In contrast, knowledge of the kinetic parameters of glucagon in humans is lacking so that measurement of glucagon secretion to date is largely qualitative. This series of experiments enabled measurement of glucagon kinetics in 51 subjects, and subsequently, stepwise linear regression was used to correlate these parameters with anthropometric characteristics. This enabled the development of a population-based model using anthropometric characteristics to predict the volume of distribution and the rate of clearance. This is a necessary first step in the development of a model to quantitate of glucagon secretion and action (and its contribution to glucose tolerance) in large populations.
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Affiliation(s)
- Marcello C Laurenti
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Adrian Vella
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Jon D Adams
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
| | | | - Aoife M Egan
- Division of Endocrinology, Diabetes & Metabolism, Mayo Clinic College of Medicine, Rochester, Minnesota
| | - Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padova, Italy
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13
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Balazki P, Schaller S, Eissing T, Lehr T. A Physiologically-Based Quantitative Systems Pharmacology Model of the Incretin Hormones GLP-1 and GIP and the DPP4 Inhibitor Sitagliptin. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2020; 9:353-362. [PMID: 32543789 PMCID: PMC7306617 DOI: 10.1002/psp4.12520] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Accepted: 05/03/2020] [Indexed: 12/16/2022]
Abstract
Incretin hormones glucagon‐like peptide‐1 (GLP‐1) and glucose‐dependent insulinotropic polypeptide (GIP) play a major role in regulation of postprandial glucose and the development of type 2 diabetes mellitus. The incretins are rapidly metabolized, primarily by the enzyme dipeptidyl‐peptidase 4 (DPP4), and the neutral endopeptidase (NEP), although the exact metabolization pathways are unknown. We developed a physiologically‐based (PB) quantitative systems pharmacology model of GLP‐1 and GIP and their metabolites that describes the secretion of the incretins in response to intraduodenal glucose infusions and their degradation by DPP4 and NEP. The model describes the observed data and suggests that NEP significantly contributes to the metabolization of GLP‐1, and the traditional assays for the total GLP‐1 and GIP forms measure yet unknown entities produced by NEP. We further extended the model with a PB pharmacokinetics/pharmacodynamics model of the DPP4 inhibitor sitagliptin that allows predictions of the effects of this medication class on incretin concentrations.
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Affiliation(s)
- Pavel Balazki
- Clinical Pharmacy Department, Saarland University, Saarbrücken, Germany.,Clinical Pharmacometrics Department, Bayer AG, Leverkusen, Germany.,esqLABS GmbH, Saterland, Germany
| | | | - Thomas Eissing
- Clinical Pharmacometrics Department, Bayer AG, Leverkusen, Germany
| | - Thorsten Lehr
- Clinical Pharmacy Department, Saarland University, Saarbrücken, Germany
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14
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Keyhani-Nejad F, Barbosa Yanez RL, Kemper M, Schueler R, Pivovarova-Ramich O, Rudovich N, Pfeiffer AFH. Endogenously released GIP reduces and GLP-1 increases hepatic insulin extraction. Peptides 2020; 125:170231. [PMID: 31870938 DOI: 10.1016/j.peptides.2019.170231] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/04/2019] [Revised: 12/05/2019] [Accepted: 12/07/2019] [Indexed: 01/01/2023]
Abstract
GIP was proposed to play a key role in the development of non- alcoholic fatty liver disease (NAFLD) in response to sugar intake. Isomaltulose, is a 1,6-linked glucose-fructose dimer which improves glucose homeostasis and prevents NAFLD compared to 1,2-linked sucrose by reducing glucose-dependent insulinotropic peptide (GIP) in mice. We compared effects of sucrose vs. isomaltulose on GIP and glucagon-like peptide-1 (GLP-1) secretion, hepatic insulin clearance (HIC) and insulin sensitivity in normal (NGT), impaired glucose tolerant (IGT) and Type 2 diabetes mellitus (T2DM) participants. A randomized crossover study was performed in 15 NGT, 10 IGT and 10 T2DM subjects. In comparison to sucrose, peak glucose concentrations were reduced by 2.3, 2.1 and 2.5 mmol/l (all p < 0.05) and insulin levels were 88% (p < 0.01, NGT), 32% (p < 0.05, IGT) and 55% (T2DM) lower after the isomaltulose load. Postprandial GIPiAUC concentrations were decreased (56%, p < 0.01 in NGT; 42%, p < 0.05 in IGT and 40%,p < 0.001 in T2DM) whereas GLP-1iAUC was 77%, 85% and 85% higher compared to sucrose (p < 0.01), respectively. This resulted in ∼35 - 50% improved insulin sensitivity and reduced insulinogenic index after isomaltulose, which correlated closely with improved HIC, respectively (r = 0.62, r=-0.70; p < 0.001). HIC was inversely related to GIP (r=-0.44, p < 0.001) and positively related to GLP-1 levels (r = 0.40, p = 0.001). CONCLUSION: Endogenously released GIP correlated with reduced, and GLP-1 with increased hepatic insulin extraction. Increased peripheral insulin levels may contribute to insulin resistance and obesity. We propose that the unfavorable effects of high glycemic index Western diets are related to increased GIP-release and reduced HIC.
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Affiliation(s)
- Farnaz Keyhani-Nejad
- Department of Clinical Nutrition, German Institute of Human Nutrition, Nuthetal, Germany; Department for Endocrinology, Diabetes and Nutrition, Charité - University of Medicine, Berlin, Germany
| | - Renate Luisa Barbosa Yanez
- Department of Clinical Nutrition, German Institute of Human Nutrition, Nuthetal, Germany; Department for Endocrinology, Diabetes and Nutrition, Charité - University of Medicine, Berlin, Germany; German Center for Diabetes Research, Partner Potsdam, Berlin, Germany
| | - Margrit Kemper
- Department of Clinical Nutrition, German Institute of Human Nutrition, Nuthetal, Germany; Department for Endocrinology, Diabetes and Nutrition, Charité - University of Medicine, Berlin, Germany; German Center for Diabetes Research, Partner Potsdam, Berlin, Germany
| | - Rita Schueler
- Department of Clinical Nutrition, German Institute of Human Nutrition, Nuthetal, Germany
| | - Olga Pivovarova-Ramich
- Department of Clinical Nutrition, German Institute of Human Nutrition, Nuthetal, Germany; Department for Endocrinology, Diabetes and Nutrition, Charité - University of Medicine, Berlin, Germany; German Center for Diabetes Research, Partner Potsdam, Berlin, Germany; Reseach Group Molecular Nutritional Medicine, Dept. of Molecular Toxicology, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
| | - Natalia Rudovich
- Department of Clinical Nutrition, German Institute of Human Nutrition, Nuthetal, Germany; Department for Endocrinology, Diabetes and Nutrition, Charité - University of Medicine, Berlin, Germany; German Center for Diabetes Research, Partner Potsdam, Berlin, Germany; Division of Endocrinology and Diabetes, Department of Internal Medicine, Spital Bülach, 8180, Bülach, Switzerland
| | - Andreas F H Pfeiffer
- Department of Clinical Nutrition, German Institute of Human Nutrition, Nuthetal, Germany; Department for Endocrinology, Diabetes and Nutrition, Charité - University of Medicine, Berlin, Germany; German Center for Diabetes Research, Partner Potsdam, Berlin, Germany.
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15
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Nauck MA. The rollercoaster history of using physiological and pharmacological properties of incretin hormones to develop diabetes medications with a convincing benefit-risk relationship. Metabolism 2020; 103:154031. [PMID: 31785258 DOI: 10.1016/j.metabol.2019.154031] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2019] [Revised: 11/15/2019] [Accepted: 11/25/2019] [Indexed: 12/13/2022]
Affiliation(s)
- Michael A Nauck
- Diabetes Division, Katholisches Klinikum Bochum, St. Josef Hospital (Ruhr-University Bochum), Gudrunstr. 56, 44791 Bochum, Germany.
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16
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Hagve M, Gjessing PF, Hole MJ, Jansen KM, Fuskevåg OM, Mollnes TE, Larsen TS, Irtun Ø. Perioperative Infusion of Glucagon-Like Peptide-1 Prevents Insulin Resistance After Surgical Trauma in Female Pigs. Endocrinology 2019; 160:2892-2902. [PMID: 31589305 DOI: 10.1210/en.2019-00374] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2019] [Accepted: 09/30/2019] [Indexed: 12/13/2022]
Abstract
Insulin resistance is an independent negative predictor of outcome after elective surgery and increases mortality among surgical patients in intensive care. The incretin hormone glucagon-like peptide-1 (GLP-1) potentiates glucose-induced insulin release from the pancreas but may also increase insulin sensitivity in skeletal muscle and directly suppress hepatic glucose release. Here, we investigated whether a perioperative infusion of GLP-1 could counteract the development of insulin resistance after surgery. Pigs were randomly assigned to three groups; surgery/control, surgery/GLP-1, and sham/GLP-1. Both surgery groups underwent major abdominal surgery. Whole-body glucose disposal (WGD) and endogenous glucose release (EGR) were assessed preoperatively and postoperatively using D-[6,6-2H2]-glucose infusion in combination with hyperinsulinemic euglycemic step-clamping. In the surgery/control group, peripheral insulin sensitivity (i.e., WGD) was reduced by 44% relative to preoperative conditions, whereas the corresponding decline was only 9% for surgery/GLP-1 (P < 0.05). Hepatic insulin sensitivity (i.e., EGR) remained unchanged in the surgery/control group but was enhanced after GLP-1 infusion in both surgery and sham animals (40% and 104%, respectively, both P < 0.05). Intraoperative plasma glucose increased in surgery/control (∼20%) but remained unchanged in both groups receiving GLP-1 (P < 0.05). GLP-1 diminished an increase in postoperative glucagon levels but did not affect skeletal muscle glycogen or insulin signaling proteins after surgery. We show that GLP-1 improves intraoperative glycemic control, diminishes peripheral insulin resistance after surgery, and suppresses EGR. This study supports the use of GLP-1 to prevent development of postoperative insulin resistance.
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Affiliation(s)
- Martin Hagve
- Gastrosurgical Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway
- Cardiovascular Research Group, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Petter F Gjessing
- Gastrosurgical Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway
- Department of Digestive Surgery, University Hospital of North Norway, Tromsø, Norway
| | - Mikal J Hole
- Gastrosurgical Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway
| | - Kirsten M Jansen
- Cardiovascular Research Group, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Ole Martin Fuskevåg
- Department of Laboratory Medicine, Division of Diagnostic Services, University Hospital of North Norway, Tromsø, Norway
| | - Tom Eirik Mollnes
- Research Laboratory, Nordland Hospital, Bodø, Norway
- Faculty of Health Sciences, K. G. Jebsen TREC, UiT The Arctic University of Norway, Tromsø, Norway
- Center of Molecular Inflammation Research and Department of Cancer Research and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway
- Department of Immunology, Oslo University Hospital, and K. G. Jebsen IRC, University of Oslo, Oslo, Norway
| | - Terje S Larsen
- Cardiovascular Research Group, Department of Medical Biology, UiT The Arctic University of Norway, Tromsø, Norway
| | - Øivind Irtun
- Gastrosurgical Research Group, Department of Clinical Medicine, UiT The Arctic University of Norway, Tromsø, Norway
- Department of Digestive Surgery, University Hospital of North Norway, Tromsø, Norway
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17
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Giblett JP, Clarke S, Zhao T, McCormick LM, Braganza DM, Densem CG, O'Sullivan M, Adlam D, Clarke SC, Steele J, Fielding S, West NE, Villar SS, Hoole SP. The role of Glucagon-Like Peptide 1 Loading on periprocedural myocardial infarction During elective PCI (GOLD-PCI study): A randomized, placebo-controlled trial. Am Heart J 2019; 215:41-51. [PMID: 31277053 DOI: 10.1016/j.ahj.2019.05.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 05/27/2019] [Indexed: 12/13/2022]
Abstract
BACKGROUND The incretin hormone glucagon-like peptide 1 (GLP-1) has been shown to protect against lethal ischemia-reperfusion injury in animal models and against nonlethal ischemia reperfusion injury in humans. Furthermore, GLP-1 receptor agonists have been shown to reduce major adverse cardiovascular and cerebrovascular events (MACCE) in large-scale studies. We sought to investigate whether GLP-1 reduced percutaneous coronary intervention (PCI)-associated myocardial infarction (PMI) during elective PCI. METHODS The study was a randomized, double-blind controlled trial in which patients undergoing elective PCI received an intravenous infusion of either GLP-1 at 1.2 pmol/kg/min or matched 0.9% saline placebo before and during the procedure. Randomization was performed in 1:1 fashion, with stratification for diabetes mellitus. Six-hour cardiac troponin I (cTnI) was measured with a primary end point of PMI defined as rise ≫×5 upper limit of normal (280 ng/L). Secondary end points included cTnI rise and MACCE at 12 months. RESULTS A total of 192 patients were randomized with 152 (79%) male and a mean age of 68.1 ± 8.9 years. No significant differences in patient demographics were noted between the groups. There was no difference in the rate of PMI between GLP-1 and placebo (9 [9.8%] vs 8 [8.3%], P = 1.0) or in the secondary end points of difference in median cTnI between groups (9.5 [0-88.5] vs 20 [0-58.5] ng/L, P = .25) and MACCE at 12 months (7 [7.3%] vs 9 [9.4%], P = .61). CONCLUSIONS In this randomized, placebo-controlled trial, GLP-1 did not reduce the low incidence of PMI or abrogate biomarker rise during elective PCI, nor did it influence the 12-month MACCE rate which also remained low. CLINICAL TRIAL REGISTRATION Clinicaltrials.gov Number: NCT02127996https://clinicaltrials.gov/ct2/show/NCT02127996.
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18
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Sood A, Swislocki A. Nonglycemic Effects of GLP-1 Agonists: From a Starling to Lizards to People. Metab Syndr Relat Disord 2019; 17:303-313. [PMID: 31145029 DOI: 10.1089/met.2018.0134] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023] Open
Abstract
With the approval of exenatide in 2005, physicians had a new class of hypoglycemic agents available for the treatment of type 2 diabetes-the glucagon-like peptide-1 receptor agonists (or GLP-1 receptor agonists). As of this writing, there are seven drugs in this class available in the United States. In addition to demonstrating either cardiovascular risk neutrality or overt benefit, as now mandated by the United States Food and Drug Administration (FDA), many of these drugs have other, unexpected actions. It is our goal to outline these actions, some beneficial, some not. We have reviewed English-language articles in this area, not for an exhaustive study, but rather a broad search to define current understanding and perhaps generate further investigation.
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Affiliation(s)
- Ajay Sood
- 1Medical Service, VA Northern California Health Care System, Martinez, California.,2Division of Endocrinology and Metabolism, Department of Internal Medicine, UC Davis School of Medicine, Sacramento, California
| | - Arthur Swislocki
- 1Medical Service, VA Northern California Health Care System, Martinez, California.,2Division of Endocrinology and Metabolism, Department of Internal Medicine, UC Davis School of Medicine, Sacramento, California
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19
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Li C, Dai S, Cao A, Zhou Z, Wu Z. Design and synthesis of rhamnose-modified exenatide conjugate by sortase A-mediated ligation. J Carbohydr Chem 2019. [DOI: 10.1080/07328303.2019.1609021] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Affiliation(s)
- Chen Li
- Key Laboratory of Carbohydrate Chemistry & Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Shijie Dai
- Key Laboratory of Carbohydrate Chemistry & Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Aijie Cao
- Key Laboratory of Carbohydrate Chemistry & Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Zhifang Zhou
- Key Laboratory of Carbohydrate Chemistry & Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
| | - Zhimeng Wu
- Key Laboratory of Carbohydrate Chemistry & Biotechnology, Ministry of Education, School of Biotechnology, Jiangnan University, Wuxi, China
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20
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Whyte MB, Shojaee-Moradie F, Sharaf SE, Jackson NC, Fielding B, Hovorka R, Mendis J, Russell-Jones D, Umpleby AM. Lixisenatide Reduces Chylomicron Triacylglycerol by Increased Clearance. J Clin Endocrinol Metab 2019; 104:359-368. [PMID: 30215735 PMCID: PMC6300412 DOI: 10.1210/jc.2018-01176] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/29/2018] [Accepted: 09/06/2018] [Indexed: 12/17/2022]
Abstract
CONTEXT Glucagon-like peptide-1 (GLP-1) agonists control postprandial glucose and lipid excursion in type 2 diabetes; however, the mechanisms are unclear. OBJECTIVE To determine the mechanisms of postprandial lipid and glucose control with lixisenatide (GLP-1 analog) in type 2 diabetes. DESIGN Randomized, double-blind, cross-over study. SETTING Centre for Diabetes, Endocrinology, and Research, Royal Surrey County Hospital, Guildford, United Kingdom. PATIENTS Eight obese men with type 2 diabetes [age, 57.3 ± 1.9 years; body mass index, 30.3 ± 1.0 kg/m2; glycosylated hemoglobin, 66.5 ± 2.6 mmol/mol (8.2% ± 0.3%)]. INTERVENTIONS Two metabolic studies, 4 weeks after lixisenatide or placebo, with cross-over and repetition of studies. MAIN OUTCOME MEASURES Study one: very-low-density lipoprotein (VLDL) and chylomicron (CM) triacylglycerol (TAG) kinetics were measured with an IV bolus of [2H5]glycerol in a 12-hour study, with hourly feeding. Oral [13C]triolein, in a single meal, labeled enterally derived TAG. Study two: glucose kinetics were measured with [U-13C]glucose in a mixed-meal (plus acetaminophen to measure gastric emptying) and variable IV [6,6-2H2]glucose infusion. RESULTS Study one: CM-TAG (but not VLDL-TAG) pool-size was lower with lixisenatide (P = 0.046). Lixisenatide reduced CM [13C]oleate area under the curve (AUC)60-480min concentration (P = 0.048) and increased CM-TAG clearance, with no effect on CM-TAG production rate. Study two: postprandial glucose and insulin AUC0-240min were reduced with lixisenatide (P = 0.0051; P < 0.05). Total glucose production (P = 0.015), rate of glucose appearance from the meal (P = 0.0098), and acetaminophen AUC0-360min (P = 0.006) were lower with lixisenatide than with placebo. CONCLUSIONS Lixisenatide reduced [13C]oleate concentrations, derived from a single meal in CM-TAG and glucose rate of appearance from the meal through delayed gastric emptying. However, day-long CM production, measured with repeated meal feeding, was not reduced by lixisenatide and decreased CM-TAG concentration resulted from increased CM-TAG clearance.
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Affiliation(s)
- Martin B Whyte
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
- Correspondence and Reprint Requests: Martin B. Whyte, PhD, FRCP, Faculty of Health and Medical Sciences, University of Surrey, Leggett Building, Daphne Jackson Road, Guildford GU2 7WG, United Kingdom. E-mail:
| | | | - Sharaf E Sharaf
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Nicola C Jackson
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Barbara Fielding
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - Roman Hovorka
- Diabetes Modelling Group, Institute of Metabolic Science, University of Cambridge, Cambridge, United Kingdom
| | - Jeewaka Mendis
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - David Russell-Jones
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
| | - A Margot Umpleby
- Faculty of Health and Medical Sciences, University of Surrey, Guildford, United Kingdom
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21
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Syed I, Lee J, Moraes-Vieira PM, Donaldson CJ, Sontheimer A, Aryal P, Wellenstein K, Kolar MJ, Nelson AT, Siegel D, Mokrosinski J, Farooqi IS, Zhao JJ, Yore MM, Peroni OD, Saghatelian A, Kahn BB. Palmitic Acid Hydroxystearic Acids Activate GPR40, Which Is Involved in Their Beneficial Effects on Glucose Homeostasis. Cell Metab 2018; 27:419-427.e4. [PMID: 29414687 PMCID: PMC5807007 DOI: 10.1016/j.cmet.2018.01.001] [Citation(s) in RCA: 120] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Revised: 08/24/2017] [Accepted: 01/03/2018] [Indexed: 12/28/2022]
Abstract
Palmitic acid hydroxystearic acids (PAHSAs) are endogenous lipids with anti-diabetic and anti-inflammatory effects. PAHSA levels are reduced in serum and adipose tissue of insulin-resistant people and high-fat diet (HFD)-fed mice. Here, we investigated whether chronic PAHSA treatment enhances insulin sensitivity and which receptors mediate PAHSA effects. Chronic PAHSA administration in chow- and HFD-fed mice raises serum and tissue PAHSA levels ∼1.4- to 3-fold. This improves insulin sensitivity and glucose tolerance without altering body weight. PAHSA administration in chow-fed, but not HFD-fed, mice augments insulin and glucagon-like peptide (GLP-1) secretion. PAHSAs are selective agonists for GPR40, increasing Ca+2 flux, but not intracellular cyclic AMP. Blocking GPR40 reverses improvements in glucose tolerance and insulin sensitivity in PAHSA-treated chow- and HFD-fed mice and directly inhibits PAHSA augmentation of glucose-stimulated insulin secretion in human islets. In contrast, GLP-1 receptor blockade in PAHSA-treated chow-fed mice reduces PAHSA effects on glucose tolerance, but not on insulin sensitivity. Thus, PAHSAs activate GPR40, which is involved in their beneficial metabolic effects.
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Affiliation(s)
- Ismail Syed
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Center for Life Sciences, Room 747, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Jennifer Lee
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Center for Life Sciences, Room 747, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Pedro M Moraes-Vieira
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Center for Life Sciences, Room 747, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Cynthia J Donaldson
- Clayton Foundation Laboratories for Peptide Biology, Helmsley Center for Genomic Medicine, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Alexandra Sontheimer
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Center for Life Sciences, Room 747, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Pratik Aryal
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Center for Life Sciences, Room 747, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Kerry Wellenstein
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Center for Life Sciences, Room 747, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Matthew J Kolar
- Clayton Foundation Laboratories for Peptide Biology, Helmsley Center for Genomic Medicine, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Andrew T Nelson
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Dionicio Siegel
- Skaggs School of Pharmacy and Pharmaceutical Sciences, University of California, San Diego, 9500 Gilman Drive, La Jolla, CA 92093, USA
| | - Jacek Mokrosinski
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge CB2 0QQ, UK
| | - I Sadaf Farooqi
- University of Cambridge Metabolic Research Laboratories and NIHR Cambridge Biomedical Research Centre, Wellcome Trust-MRC Institute of Metabolic Science, Cambridge CB2 0QQ, UK
| | - Juan Juan Zhao
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Center for Life Sciences, Room 747, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Mark M Yore
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Center for Life Sciences, Room 747, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Odile D Peroni
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Center for Life Sciences, Room 747, 330 Brookline Avenue, Boston, MA 02215, USA
| | - Alan Saghatelian
- Clayton Foundation Laboratories for Peptide Biology, Helmsley Center for Genomic Medicine, Salk Institute for Biological Studies, 10010 North Torrey Pines Road, La Jolla, CA 92037, USA
| | - Barbara B Kahn
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, Beth Israel Deaconess Medical Center and Harvard Medical School, Center for Life Sciences, Room 747, 330 Brookline Avenue, Boston, MA 02215, USA.
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Mulvihill EE. Dipeptidyl peptidase inhibitor therapy in type 2 diabetes: Control of the incretin axis and regulation of postprandial glucose and lipid metabolism. Peptides 2018; 100:158-164. [PMID: 29412815 DOI: 10.1016/j.peptides.2017.11.023] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 11/30/2017] [Accepted: 11/30/2017] [Indexed: 12/17/2022]
Abstract
Dipeptidyl peptidase 4 (DPP4) is a widely expressed, serine protease which regulates the bioactivity of many peptides through cleavage and inactivation including the incretin hormones, glucagon like peptide -1 (GLP-1) and glucose dependent insulinotropic polypeptide (GIP). Inhibitors of DPP4 are used therapeutically to treat patients with Type 2 Diabetes Mellitus (T2DM) as they potentiate incretin action to regulate islet hormone secretion and improve glycemia and post-prandial lipid excursions. The widespread clinical use of DPP4 inhibitors has increased interest in the molecular mechanisms by which these drugs mediate their beneficial effects. Traditionally, focus has remained on inhibiting the catalytic activity of DPP4 within the plasma compartment, however evidence is emerging on the importance of inactivation of membrane-bound DPP4 in selective tissue beds to potentiate local hormone gradients. Here we review the recent advances in identifying the cellular sources of both circulating and membrane-bound DPP4 important for cleavage of the incretin hormones and regulation of glucose and lipoprotein metabolism.
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Affiliation(s)
- Erin E Mulvihill
- University of Ottawa Heart Institute, University of Ottawa, Department of Biochemistry, Microbiology and Immunology, 40 Ruskin Street, Ottawa, ON, K1Y4W7, Canada.
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23
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Vella A, Camilleri M. The Gastrointestinal Tract as an Integrator of Mechanical and Hormonal Response to Nutrient Ingestion. Diabetes 2017; 66:2729-2737. [PMID: 29061658 PMCID: PMC5652608 DOI: 10.2337/dbi17-0021] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2017] [Accepted: 08/21/2017] [Indexed: 12/17/2022]
Abstract
Glucose tolerance after meal ingestion in vivo is the result of multiple processes that occur in parallel. Insulin secretion together with reciprocal inhibition of glucagon secretion contributes to glucose tolerance. However, other factors beyond glucose effectiveness and insulin action require consideration. The absorption of ingested nutrients and their subsequent systemic rate of appearance largely depend on the rate of delivery of nutrients to the proximal small intestine. This is determined by the integrated response of the upper gastrointestinal tract to a meal. While gastric emptying is probably the most significant component, other factors need to be considered. This review will examine all processes that could potentially alter the fraction and rate of appearance of ingested nutrients in the peripheral circulation. Several of these processes may be potential therapeutic targets for the prevention and treatment of diabetes. Indeed, there is increased interest in gastrointestinal contributions to nutritional homeostasis, as demonstrated by the advent of antidiabetes therapies that alter gastrointestinal motility, the effect of bariatric surgery on diabetes remission, and the potential of the intestinal microbiome as a modulator of human metabolism. The overall goal of this review is to examine current knowledge of the gastrointestinal contributions to metabolic control.
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Affiliation(s)
- Adrian Vella
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, MN
| | - Michael Camilleri
- Division of Gastroenterology and Hepatology, Mayo Clinic, Rochester, MN
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24
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Defronzo RA. Impaired glucose tolerance: do pharmacological therapies correct the underlying metabolic disturbance? ACTA ACUST UNITED AC 2016. [DOI: 10.1177/1474651403003001s0601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Lifestyle intervention prevents or delays the conversion from impaired glucose tolerance (IGT) to type 2 diabetes. However, many subjects fail to achieve and/or maintain long-term weight loss and to follow a regular exercise regimen may require pharmacologic therapy. Insulin resistance in liver, muscle and fat, along with impaired beta-cell function, plays a central role in the pathogenesis of type 2 diabetes. Insulin sensitising drugs, including metformin and the thiazolidinediones, have significantly reduced the conversion rate of IGT to type 2 diabetes in subjects in several large, well designed clinical trials. Insulin-sensitising drugs are likely to play an important role in future strategies for diabetes prevention.
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Affiliation(s)
- Ralph A Defronzo
- Diabetes Division, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA,
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25
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Abstract
Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are the known incretin hormones in humans, released predominantly from the enteroendocrine K and L cells within the gut. Their secretion is regulated by a complex of integrated mechanisms involving direct contact for the activation of different chemo-sensors on the brush boarder of K and L cells and several indirect neuro-immuno-hormonal loops. The biological actions of GIP and GLP-1 are fundamental determinants of islet function and blood glucose homeostasis in health and type 2 diabetes. Moreover, there is increasing recognition that GIP and GLP-1 also exert pleiotropic extra-glycaemic actions, which may represent therapeutic targets for human diseases. In this review, we summarise current knowledge of the biology of incretin hormones in health and metabolic disorders and highlight the therapeutic potential of incretin hormones in metabolic regulation.
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Affiliation(s)
- Tongzhi Wu
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia, 5000, Australia
| | - Christopher K Rayner
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia, 5000, Australia.
- Centre of Research Excellence in Translating Nutritional Science into Good Health, The University of Adelaide, Adelaide, Australia.
| | - Michael Horowitz
- Discipline of Medicine, The University of Adelaide, Royal Adelaide Hospital, North Terrace, Adelaide, South Australia, 5000, Australia
- Centre of Research Excellence in Translating Nutritional Science into Good Health, The University of Adelaide, Adelaide, Australia
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26
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Karstoft K, Mortensen SP, Knudsen SH, Solomon TPJ. Direct effect of incretin hormones on glucose and glycerol metabolism and hemodynamics. Am J Physiol Endocrinol Metab 2015; 308:E426-33. [PMID: 25564476 DOI: 10.1152/ajpendo.00520.2014] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
The objective of this study was to assess the insulin-independent effects of incretin hormones on glucose and glycerol metabolism and hemodynamics under euglycemic and hyperglycemic conditions. Young, healthy men (n=10) underwent three trials in a randomized, controlled, crossover study. Each trial consisted of a two-stage (euglycemia and hyperglycemia) pancreatic clamp (using somatostatin to prevent endogenous insulin secretion). Glucose and lipid metabolism was measured via infusion of stable glucose and glycerol isotopic tracers. Hemodynamic variables (femoral, brachial, and common carotid artery blood flow and flow-mediated dilation of the brachial artery) were also measured. The three trials differed as follows: 1) saline [control (CON)], 2) glucagon-like peptide (GLP-1, 0.5 pmol·kg(-1)·min(-1)), and 3) glucose-dependent insulinotropic polypeptide (GIP, 1.5 pmol·kg(-1)·min(-1)). No between-trial differences in glucose infusion rates (GIR) or glucose or glycerol kinetics were seen during euglycemia, whereas hyperglycemia resulted in increased GIR and glucose rate of disappearance during GLP-1 compared with CON and GIP (P<0.01 for all). However, when normalized to insulin levels, no differences between trials were seen for GIR or glucose rate of disappearance. Besides a higher femoral blood flow during hyperglycemia with GIP (vs. CON and GLP-1, P<0.001), no between-trial differences were seen for the hemodynamic variables. In conclusion, GLP-1 and GIP have no direct effect on whole body glucose metabolism or hemodynamics during euglycemia. On the contrary, during hyperglycemia, GIP increases femoral artery blood flow with no effect on glucose metabolism, whereas GLP-1 increases glucose disposal, potentially due to increased insulin levels.
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Affiliation(s)
- Kristian Karstoft
- Centre of Inflammation and Metabolism and Centre for Physical Activity Research, Department of Infectious Diseases, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Stefan P Mortensen
- Centre of Inflammation and Metabolism and Centre for Physical Activity Research, Department of Infectious Diseases, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; University of Southern Denmark, Odense, Denmark; and
| | - Sine H Knudsen
- Centre of Inflammation and Metabolism and Centre for Physical Activity Research, Department of Infectious Diseases, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Thomas P J Solomon
- Centre of Inflammation and Metabolism and Centre for Physical Activity Research, Department of Infectious Diseases, Rigshospitalet, Faculty of Health Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
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27
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Lu Z, Percie Du Sert N, Chan SW, Yeung CK, Lin G, Yew DTW, Andrews PLR, Rudd JA. Differential hypoglycaemic, anorectic, autonomic and emetic effects of the glucagon-like peptide receptor agonist, exendin-4, in the conscious telemetered ferret. J Transl Med 2014; 12:327. [PMID: 25491123 PMCID: PMC4272567 DOI: 10.1186/s12967-014-0327-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 11/12/2014] [Indexed: 02/02/2023] Open
Abstract
Background Rodents are incapable of emesis and consequently the emetic potential of glucagon-like peptide-1 receptor (GLP-1R) agonists in studies designed to assess a potential blood glucose lowering action of the compound was missed. Therefore, we investigated if the ferret, a carnivore with demonstrated translation capability in emesis research, would identify the emetic potential of the GLP-1R agonist, exendin-4, and any associated effects on gastric motor function, appetite and cardiovascular homeostasis. Methods The biological activity of the GLP-1R ligands was investigated in vivo using a glucose tolerance test in pentobarbitone-anesthetised ferrets and in vitro using organ bath studies. Radiotelemetry was used to investigate the effect of exendin-4 on gastric myoelectric activity (GMA) and cardiovascular function in conscious ferrets; behaviour was also simultaneously assessed. Western blot was used to characterize GLP-1R distribution in the gastrointestinal and brain tissues. Results In anesthetised ferrets, exendin-4 (30 nmol/kg, s.c.) reduced experimentally elevated blood glucose levels by 36.3%, whereas the GLP-1R antagonist, exendin (9–39) (300 nmol/kg, s.c.) antagonised the effect and increased AUC0–120 by 31.0% when injected alone (P < 0.05). In animals with radiotelemetry devices, exendin-4 (100 nmol/kg, s.c.) induced emesis in 1/9 ferrets, but inhibited food intake and decreased heart rate variability (HRV) in all animals (P < 0.05). In the animals not exhibiting emesis, there was no effect on GMA, mean arterial blood pressure, heart rate, or core body temperature. In the ferret exhibiting emesis, there was a shift in the GMA towards bradygastria with a decrease in power, and a concomitant decrease in HRV. Western blot revealed GLP-1R throughout the gastrointestinal tract but exendin-4 (up to 300 nM) and exendin (9–39), failed to contract or relax isolated ferret gut tissues. GLP-1R were found in all major brain regions and the levels were comparable those in the vagus nerve. Conclusions Peripherally administered exendin-4 reduced blood glucose and inhibited feeding with a low emetic potential similar to that in humans (11% vs 12.8%). A disrupted GMA only occurred in the animal exhibiting emesis raising the possibility that disruption of the GMA may influence the probability of emesis occurring in response to treatment with GLP-1R agonists.
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Affiliation(s)
- Zengbing Lu
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China.
| | | | - Sze Wa Chan
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China.
| | - Chi-Kong Yeung
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China.
| | - Ge Lin
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China.
| | - David T W Yew
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China.
| | - Paul L R Andrews
- Division of Biomedical Sciences, St George's University of London, London, UK.
| | - John A Rudd
- School of Biomedical Sciences, Faculty of Medicine, The Chinese University of Hong Kong, Shatin, New Territories, Hong Kong, SAR, China.
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28
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Pabreja K, Mohd MA, Koole C, Wootten D, Furness SGB. Molecular mechanisms underlying physiological and receptor pleiotropic effects mediated by GLP-1R activation. Br J Pharmacol 2014; 171:1114-28. [PMID: 23889512 DOI: 10.1111/bph.12313] [Citation(s) in RCA: 51] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Revised: 07/10/2013] [Accepted: 07/19/2013] [Indexed: 12/22/2022] Open
Abstract
The incidence of type 2 diabetes in developed countries is increasing yearly with a significant negative impact on patient quality of life and an enormous burden on the healthcare system. Current biguanide and thiazolidinedione treatments for type 2 diabetes have a number of clinical limitations, the most serious long-term limitation being the eventual need for insulin replacement therapy (Table 1). Since 2007, drugs targeting the glucagon-like peptide-1 (GLP-1) receptor have been marketed for the treatment of type 2 diabetes. These drugs have enjoyed a great deal of success even though our underlying understanding of the mechanisms for their pleiotropic effects remain poorly characterized even while major pharmaceutical companies actively pursue small molecule alternatives. Coupling of the GLP-1 receptor to more than one signalling pathway (pleiotropic signalling) can result in ligand-dependent signalling bias and for a peptide receptor such as the GLP-1 receptor this can be exaggerated with the use of small molecule agonists. Better consideration of receptor signalling pleiotropy will be necessary for future drug development. This is particularly important given the recent failure of taspoglutide, the report of increased risk of pancreatitis associated with GLP-1 mimetics and the observed clinical differences between liraglutide, exenatide and the newly developed long-acting exenatide long acting release, albiglutide and dulaglutide.
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Affiliation(s)
- K Pabreja
- Drug Discovery Biology, Monash Institute of Pharmaceutical Sciences, Monash University, Parkville, Vic., Australia
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29
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Yang X, Li Y, Wang Y, Zheng X, Kong W, Meng F, Zhou Z, Liu C, Li Y, Gong M. Long-Acting GLP-1 Analogue in V-Shaped Conformation by Terminal Polylysine Modifications. Mol Pharm 2014; 11:4092-9. [PMID: 25243635 DOI: 10.1021/mp5002685] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Affiliation(s)
- Xue Yang
- Department of Pharmacy, Tianjin Traditional Medicine University, Tianjin, China
| | - Ying Li
- Tianjin Neurological
Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Yuli Wang
- Tianjin Institute of Pharmaceutical Research, Tianjin, China
| | - Xuemin Zheng
- Tianjin Institute of Pharmaceutical Research, Tianjin, China
| | - Weiling Kong
- Tianjin Institute of Pharmaceutical Research, Tianjin, China
| | - Fancui Meng
- Tianjin Institute of Pharmaceutical Research, Tianjin, China
| | - Zhixing Zhou
- Tianjin Institute of Pharmaceutical Research, Tianjin, China
| | - Changxiao Liu
- Tianjin Institute of Pharmaceutical Research, Tianjin, China
| | - Ying Li
- Tianjin Neurological
Institute, Tianjin Medical University General Hospital, Tianjin, China
| | - Min Gong
- Tianjin Institute of Pharmaceutical Research, Tianjin, China
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30
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Ang M, Linn T. Comparison of the effects of slowly and rapidly absorbed carbohydrates on postprandial glucose metabolism in type 2 diabetes mellitus patients: a randomized trial. Am J Clin Nutr 2014; 100:1059-68. [PMID: 25030779 DOI: 10.3945/ajcn.113.076638] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
BACKGROUND Isomaltulose attenuates postprandial glucose and insulin concentrations compared with sucrose in patients with type 2 diabetes mellitus (T2DM). However, the mechanism by which isomaltulose limits postprandial hyperglycemia has not been clarified. OBJECTIVE The objective was therefore to assess the effects of bolus administration of isomaltulose on glucose metabolism compared with sucrose in T2DM. DESIGN In a randomized, double-blind, crossover design, 11 participants with T2DM initially underwent a 3-h euglycemic-hyperinsulinemic (0.8 mU · kg(-1) · min(-1)) clamp that was subsequently combined with 1 g/kg body wt of an oral (13)C-enriched isomaltulose or sucrose load. Hormonal responses and glucose kinetics were analyzed during a 4-h postprandial period. RESULTS Compared with sucrose, absorption of isomaltulose was prolonged by ∼50 min (P = 0.004). Mean plasma concentrations of insulin, C-peptide, glucagon, and glucose-dependent insulinotropic peptide were ∼10-23% lower (P < 0.05). In contrast, glucagon-like peptide 1 (GLP-1) was ∼64% higher (P < 0.001) after isomaltulose ingestion, which results in an increased insulin-to-glucagon ratio (P < 0.001) compared with sucrose. The cumulative amount of systemic glucose appearance was ∼35% lower after isomaltulose than after sucrose (P = 0.003) because of the reduction in orally derived and endogenously produced glucose and a higher first-pass splanchnic glucose uptake (SGU). Insulin action was enhanced after isomaltulose compared with sucrose (P = 0.013). CONCLUSIONS Ingestion of slowly absorbed isomaltulose attenuates postprandial hyperglycemia by reducing oral glucose appearance, inhibiting endogenous glucose production (EGP), and increasing SGU compared with ingestion of rapidly absorbed sucrose in patients with T2DM. In addition, GLP-1 secretion contributes to a beneficial shift in the insulin-to-glucagon ratio, suppression of EGP, and enhancement of SGU after isomaltulose consumption. This trial was registered at clinicaltrials.gov as NCT01070238.
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Affiliation(s)
- Meidjie Ang
- From Medical Clinic and Policlinic 3, Justus Liebig University, Giessen, Germany
| | - Thomas Linn
- From Medical Clinic and Policlinic 3, Justus Liebig University, Giessen, Germany
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31
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Trung VN, Yamamoto H, Murata S, Kuwahara A, Tani T. Ileal glucose infusion leads to increased insulin sensitivity and decreased blood glucose levels in Wistar rats. J INVEST SURG 2014; 27:332-7. [PMID: 24960307 DOI: 10.3109/08941939.2014.929764] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
PURPOSE OF THE STUDY Rerouting of nutrients and/or increasing nutrient delivery to the small intestine after Roux-en-Y gastric bypass may have important potential as a diabetes treatment modality. However, it is still important question which part of the gastrointestinal tract is the most important for control of glycemia. The aim of this study was to investigate the role of different segments of the gastrointestinal tract on glucose metabolism in the physiological state. MATERIALS AND METHODS Forty 12-week-old male Wistar rats were divided into the following four groups of 10 animals each: the gastrostomy group, the duodenostomy group, the jejunostomy group, and the ileostomy group. All rats were subjected to a glucose tolerance test by infusion of glucose via the surgically inserted tubes in the stomach (gastrostomy), in the duodenum (duodenostomy), in the jejunum (jejunostomy), or in the ileum (ileostomy). Plasma glucagon-like peptide-17-36 (GLP-17-36) and insulin levels during the glucose tolerance test were assayed and Matsuda index was calculated. RESULTS Ileostomy rats exhibited significantly lower glycemic excursions compared with gastrostomy, duodenostomy, and jejunostomy rats. Insulin and GLP-1 levels during the glucose tolerance test were significantly higher in duodenostomy and jejunostomy rats than in gastrostomy and ileostomy rats. Matsuda index was significantly higher in ileostomy rats than in duodenostomy and jejunostomy rats. CONCLUSION Ileal glucose infusion leads to increased insulin sensitivity, further decreasing blood glucose levels.
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Affiliation(s)
- Vo Nguyen Trung
- 1Department of Surgery, Shiga University of Medical Science, Seta-Tsukinowa-cho, Otsu, Shiga, Japan
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One-Step Purification of a Fusion Protein of Glucagon-Like Peptide-1 and Human Serum Albumin Expressed inPichia pastorisby an Immunomagnetic Separation Technique. Biosci Biotechnol Biochem 2014; 71:2655-62. [DOI: 10.1271/bbb.70190] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Sathananthan M, Farrugia LP, Miles JM, Piccinini F, Dalla Man C, Zinsmeister AR, Cobelli C, Rizza RA, Vella A. Direct effects of exendin-(9,39) and GLP-1-(9,36)amide on insulin action, β-cell function, and glucose metabolism in nondiabetic subjects. Diabetes 2013; 62:2752-6. [PMID: 23545708 PMCID: PMC3717878 DOI: 10.2337/db13-0140] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/21/2022]
Abstract
Exendin-(9,39) is a competitive antagonist of glucagon-like peptide-1 (GLP-1) at its receptor. However, it is unclear if it has direct and unique effects of its own. We tested the hypothesis that exendin-(9,39) and GLP-1-(9,36)amide have direct effects on hormone secretion and β-cell function as well as glucose metabolism in healthy subjects. Glucose containing [3-(3)H]glucose was infused to mimic the systemic appearance of glucose after a meal. Saline, GLP-1-(9,36)amide, or exendin-(9,39) at 30 pmol/kg/min (Ex 30) or 300 pmol/kg/min (Ex 300) were infused in random order on separate days. Integrated glucose concentrations were slightly but significantly increased by exendin-(9,39) (365 ± 43 vs. 383 ± 35 vs. 492 ± 49 vs. 337 ± 50 mmol per 6 h, saline, Ex 30, Ex 300, and GLP-1-[9,36]amide, respectively; P = 0.05). Insulin secretion did not differ among groups. However, insulin action was lowered by exendin-(9,39) (25 ± 4 vs. 20 ± 4 vs. 18 ± 3 vs. 21 ± 4 10(-4) dL/kg[min per μU/mL]; P = 0.02), resulting in a lower disposition index (DI) during exendin-(9,39) infusion (1,118 ± 118 vs. 816 ± 83 vs. 725 ± 127 vs. 955 ± 166 10(-14) dL/kg/min(2) per pmol/L; P = 0.003). Endogenous glucose production and glucose disappearance did not differ significantly among groups. We conclude that exendin-(9,39), but not GLP-1-(9,36)amide, decreases insulin action and DI in healthy humans.
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Affiliation(s)
- Matheni Sathananthan
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - Luca P. Farrugia
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - John M. Miles
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | | | - Chiara Dalla Man
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Alan R. Zinsmeister
- Division of Biomedical Statistics and Informatics, Mayo Clinic, Rochester, Minnesota
| | - Claudio Cobelli
- Department of Information Engineering, University of Padua, Padua, Italy
| | - Robert A. Rizza
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
| | - Adrian Vella
- Division of Endocrinology, Diabetes, Metabolism, and Nutrition, Mayo Clinic, Rochester, Minnesota
- Corresponding author: Adrian Vella,
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Edgerton DS, An Z, Johnson KMS, Farmer T, Farmer B, Neal D, Cherrington AD. Effects of intraportal exenatide on hepatic glucose metabolism in the conscious dog. Am J Physiol Endocrinol Metab 2013; 305:E132-9. [PMID: 23673158 PMCID: PMC3725568 DOI: 10.1152/ajpendo.00160.2013] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
Incretins improve glucose metabolism through multiple mechanisms. It remains unclear whether direct hepatic effects are an important part of exenatide's (Ex-4) acute action. Therefore, the objective of this study was to determine the effect of intraportal delivery of Ex-4 on hepatic glucose production and uptake. Fasted conscious dogs were studied during a hyperglycemic clamp in which glucose was infused into the hepatic portal vein. At the same time, portal saline (control; n = 8) or exenatide was infused at low (0.3 pmol·kg⁻¹·min⁻¹, Ex-4-low; n = 5) or high (0.9 pmol·kg⁻¹·min⁻¹, Ex-4-high; n = 8) rates. Arterial plasma glucose levels were maintained at 160 mg/dl during the experimental period. This required a greater rate of glucose infusion in the Ex-4-high group (1.5 ± 0.4, 2.0 ± 0.7, and 3.7 ± 0.7 mg·kg⁻¹·min⁻¹ between 30 and 240 min in the control, Ex-4-low, and Ex-4-high groups, respectively). Plasma insulin levels were elevated by Ex-4 (arterial: 4,745 ± 428, 5,710 ± 355, and 7,262 ± 1,053 μU/ml; hepatic sinusoidal: 14,679 ± 1,700, 15,341 ± 2,208, and 20,445 ± 4,020 μU/ml, 240 min, area under the curve), whereas the suppression of glucagon was nearly maximal in all groups. Although glucose utilization was greater during Ex-4 infusion (5.92 ± 0.53, 6.41 ± 0.57, and 8.12 ± 0.54 mg·kg⁻¹·min⁻¹), when indices of hepatic, muscle, and whole body glucose uptake were expressed relative to circulating insulin concentrations, there was no indication of insulin-independent effects of Ex-4. Thus, this study does not support the notion that Ex-4 generates acute changes in hepatic glucose metabolism through direct effects on the liver.
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Affiliation(s)
- Dale S Edgerton
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA.
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Seghieri M, Rebelos E, Gastaldelli A, Astiarraga BD, Casolaro A, Barsotti E, Pocai A, Nauck M, Muscelli E, Ferrannini E. Direct effect of GLP-1 infusion on endogenous glucose production in humans. Diabetologia 2013; 56:156-61. [PMID: 23064290 DOI: 10.1007/s00125-012-2738-3] [Citation(s) in RCA: 100] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Accepted: 08/29/2012] [Indexed: 01/08/2023]
Abstract
AIMS/HYPOTHESIS Glucagon-like peptide-1 (GLP-1) lowers glucose levels by potentiating glucose-induced insulin secretion and inhibiting glucagon release. The question of whether GLP-1 exerts direct effects on the liver, independently of the hormonal changes, is controversial. We tested whether an exogenous GLP-1 infusion, designed to achieve physiological postprandial levels, directly affects endogenous glucose production (EGP) under conditions mimicking the fasting state in diabetes. METHODS In 14 healthy volunteers, we applied the pancreatic clamp technique, whereby plasma insulin and glucagon levels are clamped using somatostatin and hormone replacement. The clamp was applied in paired, 4 h experiments, during which saline (control) or GLP-1(7-37)amide (0.4 pmol min⁻¹ kg⁻¹) was infused. RESULTS During the control study, plasma insulin and glucagon were maintained at basal levels and plasma C-peptide was suppressed, such that plasma glucose rose to a plateau of ~10.5 mmol/l and tracer-determined EGP increased by ~60%. During GLP-1 infusion at matched plasma glucose levels, the rise of EGP from baseline was fully prevented. Lipolysis (as indexed by NEFA concentrations and tracer-determined glycerol rate of appearance) and substrate utilisation (by indirect calorimetry) were similar between control and GLP-1 infusion. CONCLUSIONS/INTERPRETATION GLP-1 inhibits EGP under conditions where plasma insulin and glucagon are not allowed to change and glucose concentrations are matched, indicating either a direct effect on hepatocytes or neurally mediated inhibition.
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Affiliation(s)
- M Seghieri
- Department of Internal Medicine, University of Pisa School of Medicine, Via Roma, 67, 56100 Pisa, Italy
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Abstract
AIMS/HYPOTHESIS Glucagon-like peptide-1 (GLP-1) lowers glucose levels by potentiating glucose-induced insulin secretion and inhibiting glucagon release. The question of whether GLP-1 exerts direct effects on the liver, independently of the hormonal changes, is controversial. We tested whether an exogenous GLP-1 infusion, designed to achieve physiological postprandial levels, directly affects endogenous glucose production (EGP) under conditions mimicking the fasting state in diabetes. METHODS In 14 healthy volunteers, we applied the pancreatic clamp technique, whereby plasma insulin and glucagon levels are clamped using somatostatin and hormone replacement. The clamp was applied in paired, 4 h experiments, during which saline (control) or GLP-1(7-37)amide (0.4 pmol min⁻¹ kg⁻¹) was infused. RESULTS During the control study, plasma insulin and glucagon were maintained at basal levels and plasma C-peptide was suppressed, such that plasma glucose rose to a plateau of ~10.5 mmol/l and tracer-determined EGP increased by ~60%. During GLP-1 infusion at matched plasma glucose levels, the rise of EGP from baseline was fully prevented. Lipolysis (as indexed by NEFA concentrations and tracer-determined glycerol rate of appearance) and substrate utilisation (by indirect calorimetry) were similar between control and GLP-1 infusion. CONCLUSIONS/INTERPRETATION GLP-1 inhibits EGP under conditions where plasma insulin and glucagon are not allowed to change and glucose concentrations are matched, indicating either a direct effect on hepatocytes or neurally mediated inhibition.
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Hellström PM, Smithson A, Stowell G, Greene S, Kenny E, Damico C, Leone-Bay A, Baughman R, Grant M, Richardson P. Receptor-mediated inhibition of small bowel migrating complex by GLP-1 analog ROSE-010 delivered via pulmonary and systemic routes in the conscious rat. ACTA ACUST UNITED AC 2012; 179:71-6. [PMID: 22960405 DOI: 10.1016/j.regpep.2012.08.009] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2011] [Revised: 06/30/2012] [Accepted: 08/27/2012] [Indexed: 12/17/2022]
Abstract
BACKGROUND ROSE-010, a Glucagon-Like Peptide-1 (GLP-1) analog, reduces gastrointestinal motility and relieves acute pain in patients with irritable bowel syndrome (IBS). The rat small bowel migrating myoelectric complex (MMC) is a reliable model of pharmacological effects on gastrointestinal motility. Accordingly, we investigated whether ROSE-010 works through GLP-1 receptors in gut musculature and its effectiveness when administered by pulmonary inhalation. MATERIALS AND METHODS Rats were implanted with bipolar electrodes at 5, 15 and 25 cm distal to pylorus and myoelectric activity was recorded. First, intravenous or subcutaneous injections of ROSE-010 or GLP-1 (1, 10, 100 μg/kg) with or without the GLP-1 receptor blocker exendin(9-39)amide (300 μg/kg·h), were studied. Second, ROSE-010 (100, 200 μg/kg) Technosphere® powder was studied by inhalation. RESULTS The baseline MMC cycle length was 17.5±0.8 min. GLP-1 and ROSE-010, administered intravenously or subcutaneously, significantly inhibited myoelectric activity and prolonged MMC cycling; 100 μg/kg completely inhibited spiking activity for 49.1±4.2 and 73.3±7.7 min, while the MMC cycle length increased to 131.1±11.4 and 149.3±15.5 min, respectively. Effects of both drugs were inhibited by exendin(9-39)amide. Insufflation of ROSE-010 (100, 200 μg/kg) powder formulation totally inhibited myoelectric spiking for 52.6±5.8 and 70.1±5.4 min, and increased MMC cycle length to 102.6±18.3 and 105.9±9.5 min, respectively. CONCLUSIONS Pulmonary delivery of ROSE-010 inhibits gut motility through the GLP-1R similar to natural GLP-1. ROSE-010 causes receptor-mediated inhibition of MMC comparable to that of intravenous or subcutaneous administration. This suggests that ROSE-010 administered as a Technosphere® inhalation powder has potential in IBS pain management and treatment.
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Affiliation(s)
- P M Hellström
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
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Muscelli E, Casolaro A, Gastaldelli A, Mari A, Seghieri G, Astiarraga B, Chen Y, Alba M, Holst J, Ferrannini E. Mechanisms for the antihyperglycemic effect of sitagliptin in patients with type 2 diabetes. J Clin Endocrinol Metab 2012; 97:2818-26. [PMID: 22685234 DOI: 10.1210/jc.2012-1205] [Citation(s) in RCA: 79] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
CONTEXT Dipeptidyl peptidase IV (DPP-4) inhibitors improve glycemic control in patients with type 2 diabetes. The underlying mechanisms (incretin effect, β-cell function, endogenous glucose production) are not well known. OBJECTIVE The aim of the study was to examine mechanisms of the antihyperglycemic effect of DPP-4 inhibitors. DESIGN, SETTING, AND PATIENTS We administered a mixed meal with glucose tracers ([6,6-(2)H(2)]-glucose infused, [1-(2)H]-glucose ingested), and on a separate day, a glucose infusion matched the glucose responses to the meal (isoglycemic test) in 50 type 2 diabetes patients (hemoglobin A(1c) = 7.4 ± 0.8%) and seven controls; 47 diabetic completers were restudied after 6 wk. Glucose fluxes were calculated, and β-cell function was assessed by mathematical modeling. The incretin effect was calculated as the ratio of oral to iv insulin secretion. INTERVENTION We conducted a 6-wk, double-blind, randomized treatment with sitagliptin (100 mg/d; n = 25) or placebo (n = 22). RESULTS Relative to placebo, meal-induced changes in fasting glucose and glucose area under the curve (AUC) were greater with sitagliptin, in parallel with a lower appearance of oral glucose [difference (post-pre) AUC = -353 ± 915 vs. +146 ± 601 μmol · kg(-1) · 5 h] and greater suppression of endogenous glucose production. Insulin sensitivity improved 10%, whereas total insulin secretion was unchanged. During the meal, β-cell glucose sensitivity improved (+19[29] vs. 5[21] pmol · min(-1) · m(-2) · mm(-1); median [interquartile range]) and glucagon AUC decreased (19.6 ± 7.5 to 17.3 ± 7.1 ng · ml(-1) · 5 h), whereas intact glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1 AUC increased with sitagliptin vs. placebo. The incretin effect was unchanged because sitagliptin increased β-cell glucose sensitivity also during the isoglycemic test. CONCLUSIONS Chronic sitagliptin treatment improves glycemic control by lowering the appearance of oral glucose, postprandial endogenous glucose release, and glucagon response, and by improving insulin sensitivity and β-cell glucose sensing in response to both oral and iv glucose.
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Affiliation(s)
- Elza Muscelli
- Department of Internal Medicine, University of Pisa School of Medicine, 56100 Pisa, Italy
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Cao Z, Li Y, Tang L, Xu W, Liu C, Zhang J, Gong M. Formation of cyclic structure at amino-terminus of glucagon-like peptide-1 exhibited a prolonged half-life in vivo. Diabetes Res Clin Pract 2012; 96:362-70. [PMID: 22284602 DOI: 10.1016/j.diabres.2012.01.010] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/12/2011] [Revised: 12/12/2011] [Accepted: 01/03/2012] [Indexed: 11/20/2022]
Abstract
The multiple physiological characterizations of glucagon-like peptide-1 (GLP-1) make it a promising drug candidate for the therapy of type 2 diabetes. However, the biological half-life of GLP-1 is short in vivo due to degradation by dipeptidyl peptidase-IV (DPP-IV) and renal clearance. The stabilization of GLP-1 is critical for its utility in drug development. In this study, several GLP-1 mutants containing an N-terminal cyclic conformation were prepared in that the existence of cyclic conformation is predicted to increase the stabilization of GLP-1 in vivo. In this study, the binding capacities of the mutants were determined, the stabilities of the mutants were investigated and the physiological functions of the mutants were compared with those of wild-type GLP-1 in animals. The results indicated that the mutant (GLP1N8) remarkably raised the half-life in vivo; it also showed better glucose tolerance and higher HbA(1c) reduction than GLP-1 and exendin-4 in rodents. These results suggest that the GLP-1 analog (GLP1N8) which contains an N-terminal cyclic structure might be utilized as possible potent anti-diabetic drugs in the treatment of type 2 diabetes mellitus.
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Affiliation(s)
- Zhenghong Cao
- Department of Pharmacy, Tianjin University of Traditional Medicine, China
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Smushkin G, Sathananthan A, Man CD, Zinsmeister AR, Camilleri M, Cobelli C, Rizza RA, Vella A. Defects in GLP-1 response to an oral challenge do not play a significant role in the pathogenesis of prediabetes. J Clin Endocrinol Metab 2012; 97:589-98. [PMID: 22090278 PMCID: PMC3275363 DOI: 10.1210/jc.2011-2561] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
CONTEXT There has been much speculation as to whether defects in glucagon-like peptide-1 (GLP-1) secretion play a role in the pathogenesis of type 2 diabetes and the progression from normal glucose tolerance to prediabetes and diabetes. OBJECTIVE Our objective was to determine whether fasting and postchallenge concentrations of active and total GLP-1 decrease as glucose tolerance and insulin secretion worsen across the spectrum of prediabetes. DESIGN This was a cross-sectional study. SETTING The study was performed in the clinical research unit of an academic medical center. PARTICIPANTS Participants included 165 subjects with a fasting glucose below 7.0 mmol/liter and not taking medications known to affect gastrointestinal motility or glucose metabolism. INTERVENTION Intervention included a 2-h, 75-g oral glucose tolerance test with insulin, C-peptide, glucagon, and GLP-1 measurements at seven time points. MAIN OUTCOME MEASURE We evaluated the association of integrated, incremental active, and total GLP-1 concentrations with integrated, incremental glucose response to 75 g oral glucose. RESULTS After accounting for covariates, there was no evidence of a relationship of incremental glucose concentrations after oral glucose tolerance test with active and total GLP-1 (r(s) = -0.16 and P = 0.14, and r(s) = 0.00 and P > 0.9, respectively). There also was no association of GLP-1 concentrations with insulin secretion and action. CONCLUSIONS The lack of association of GLP-1 concentrations with glucose tolerance status and with insulin secretion and action in a cohort encompassing the full spectrum of prediabetes strongly argues against a significant contribution of defects in GLP-1 secretion to the pathogenesis of prediabetes.
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Affiliation(s)
- Galina Smushkin
- Division of Endocrinology, Mayo Clinic, Rochester, Minnesota 55905, USA
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A physiological role of glucagon-like peptide-1 receptors in the central nervous system of Suncus murinus (house musk shrew). Eur J Pharmacol 2011; 668:340-6. [DOI: 10.1016/j.ejphar.2011.06.036] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2011] [Revised: 06/09/2011] [Accepted: 06/23/2011] [Indexed: 11/24/2022]
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Zheng X, Li Y, Li X, Tang L, Xu W, Gong M. Peptide complex containing GLP-1 exhibited long-acting properties in the treatment of type 2 diabetes. Diabetes Res Clin Pract 2011; 93:410-20. [PMID: 21641071 DOI: 10.1016/j.diabres.2011.05.021] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/14/2011] [Revised: 04/30/2011] [Accepted: 05/10/2011] [Indexed: 10/18/2022]
Abstract
The multiple physiological characterizations of glucagon-like peptide-1 (GLP-1) make it a promising drug candidate for the treatment of type 2 diabetes. However, in vivo, the half-life of GLP-1 is short, which is caused by the degradation of dipeptidyl peptidase-IV (DPP-IV) and renal clearance. Thus, the stabilization of GLP-1 is critical for its utility in drug development. Peptides known as GLP-1 protectors are predicted to increase the half-life of GLP-1 in vivo. Protecting peptides are able to form stable complexes by non-covalent interactions with human GLP-1. In this study, the stability of the complex was investigated, and the physiological functions of the GLP-1/peptide 1 complex were compared to those of exenatide and liraglutide in animals. The results indicated that the GLP-1/peptide 1 complex remarkably raised the half-life of GLP-1 in vivo and showed better glucose tolerance and higher HbA(1c) reduction than exenatide and liraglutide in rodents. Based upon these results, it is suggested that the GLP-1/peptide 1 complex might be utilized as a possible potent anti-diabetic drug in the treatment of type 2 diabetes mellitus.
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Affiliation(s)
- Xuemin Zheng
- Department of Pharmaceutical Analysis, Tianjin University of Traditional Chinese Medicine, China
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Hjøllund KR, Deacon CF, Holst JJ. Dipeptidyl peptidase-4 inhibition increases portal concentrations of intact glucagon-like peptide-1 (GLP-1) to a greater extent than peripheral concentrations in anaesthetised pigs. Diabetologia 2011; 54:2206-8. [PMID: 21604085 DOI: 10.1007/s00125-011-2168-7] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/23/2010] [Accepted: 04/06/2011] [Indexed: 11/24/2022]
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Li Y, Li X, Zheng X, Tang L, Xu W, Gong M. Disulfide bond prolongs the half-life of therapeutic peptide-GLP-1. Peptides 2011; 32:1400-7. [PMID: 21600946 DOI: 10.1016/j.peptides.2011.05.003] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2011] [Revised: 05/04/2011] [Accepted: 05/04/2011] [Indexed: 11/19/2022]
Abstract
The multiple physiological characterization of glucagon-like peptide-1 (GLP-1) makes it a promising drug candidate for the therapy of type 2 diabetes. However, the half-life of GLP-1 is short in vivo due to rapid degradation by dipeptidyl peptidase-IV (DPP-IV) and renal clearance. This indicates that the stabilization of GLP-1 is critical for its utility in drug development. In this study, we developed a cluster of GLP-1 homodimeric analogs, which fused the mutated GLP-1 monomer by an intra-disulfide bridge. The stabilities of the GLP-1 homodimeric analogs were investigated and the physiological functions of the analogs were compared with those of wild-type GLP-1 in rats and human serum. Single dose glucose tolerance test was performed to investigate the administration frequency which satisfied the efficient glucose regulatory in rats. Multiple dose glucose tolerance tests were employed also to study the long-acting anti-diabetic activity of GLP-1 homodimeric analog. The results indicated that the GLP-1 homodimeric analog (hdGLP1G10C) remarkably raised the biological half-life of GLP-1; also HDGLP1G10C showed better glucose tolerance and higher HbA(1c) reduction than GLP-1 in rodents. Based upon the results in this study, it was suggested that hdGLP1G10C prolonged the stability of GLP-1 and retained the biological activity of GLP-1. The improved physiological characterization of hdGLP1G10C makes it as possible potent anti-diabetic drug in the treatment of type 2 diabetes mellitus.
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Affiliation(s)
- Ying Li
- School of Biosciences, University of Birmingham, United Kingdom
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Li Y, Xu W, Tang L, Gong M, Zhang J. A novel GLP-1 analog exhibits potent utility in the treatment of type 2 diabetes with an extended half-life and efficient glucose clearance in vivo. Peptides 2011; 32:1408-14. [PMID: 21664938 DOI: 10.1016/j.peptides.2011.05.026] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2011] [Revised: 05/26/2011] [Accepted: 05/26/2011] [Indexed: 11/24/2022]
Abstract
The multiple physiological characterizations of glucagon-like peptide-1 (GLP-1) make it a promising drug candidate for the therapy of type 2 diabetes. However, the half-life of GLP-1 is short in vivo due to degradation by dipeptidyl peptidase-IV (DPP-IV) and renal clearance. Therefore, the stabilization of GLP-1 is critical for its utility in drug development. Based on our previous research, a GLP-1 analog that contained an intra-disulfide bond exhibited a prolonged biological half-life. In this study, we improved upon previous analogs with a novel GLP-1 analog that contained a tryptophan cage-like sequence for an improved binding affinity to the GLP-1 receptor. The binding capacities and the stabilities of GLP715a were investigated, and the physiological functions of the GLP715a were compared to those of the wild-type GLP-1 in animals. The results demonstrated that the new GLP-1 analog (GLP715a) increased its biological half-life to approximately 48h in vivo; GLP715a also exhibited a higher binding affinity to the GLP-1 receptor than the wild-type GLP-1. The increased binding capacity of GLP715a to its receptor resulted in a quick response to glucose administration. The long-acting anti-diabetic property of GLP715a was revealed by its increased glucose tolerance, higher HbA(1c) reduction, more efficient glucose clearance and quicker insulin stimulation upon glucose administration compared to the wild-type GLP-1 in rodents. The improved physiological characterizations of GLP715a make it a possible potent anti-diabetic drug in the treatment of type 2 diabetes mellitus.
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Affiliation(s)
- Ying Li
- School of Bioscience, University of Birmingham, UK
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Li Y, Zheng X, Tang L, Xu W, Gong M. GLP-1 analogs containing disulfide bond exhibited prolonged half-life in vivo than GLP-1. Peptides 2011; 32:1303-12. [PMID: 21515323 DOI: 10.1016/j.peptides.2011.04.001] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/08/2011] [Revised: 04/07/2011] [Accepted: 04/07/2011] [Indexed: 01/08/2023]
Abstract
The multiple physiological characterizations of glucagon-like peptide-1 (GLP-1) make it a promising drug candidate for the therapy of type 2 diabetes. However, the half-life of GLP-1 is short in vivo due to degradation by dipeptidyl peptidase-IV (DPP-IV) and renal clearance. This indicates that the stabilization of GLP-1 is critical for its utility in drug development. In this study, we developed a cluster of GLP-1 mutants containing an inter-disulfide bond that is predicted to increase the half-life of GLP-1 in vivo. Exendin-4 was also mutated with a disulfide bond similar to the GLP-1 analogs. In this study, the binding capacities of the mutants were determined, the stabilities of the mutants were investigated and the physiological functions of the mutants were compared with those of wild-type GLP-1 and exendin-4 in animals. The results indicated that the mutants remarkably raised the half-life in vivo; they also showed better glucose tolerance and higher HbA(1c) reduction than GLP-1 and exendin-4 in rodents. These results suggest that GLP-1 and exendin-4 mutants containing disulfide bonds might be utilized as possible potent anti-diabetic drugs in the treatment of type 2 diabetes mellitus.
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Affiliation(s)
- Ying Li
- School of Biosciences, University of Birmingham, UK
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Cersosimo E, Gastaldelli A, Cervera A, Wajcberg E, Sriwijilkamol A, Fernandez M, Zuo P, Petz R, Triplitt C, Musi N, DeFronzo RA. Effect of exenatide on splanchnic and peripheral glucose metabolism in type 2 diabetic subjects. J Clin Endocrinol Metab 2011; 96:1763-70. [PMID: 21411546 DOI: 10.1210/jc.2010-2146] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/12/2023]
Abstract
OBJECTIVE Our objective was to examine the mechanisms via which exenatide attenuates postprandial hyperglycemia in type 2 diabetes mellitus (T2DM). STUDY DESIGN Seventeen T2DM patients (44 yr; seven females, 10 males; body mass index = 33.6 kg/m(2); glycosylated hemoglobin = 7.9%) received a mixed meal followed for 6 h with double-tracer technique ([1-(14)C]glucose orally; [3-(3)H]glucose i.v.) before and after 2 wk of exenatide. In protocol II (n = 5), but not in protocol I (n = 12), exenatide was given in the morning of the repeat meal. Total and oral glucose appearance rates (RaT and RaO, respectively), endogenous glucose production (EGP), splanchnic glucose uptake (75 g - RaO), and hepatic insulin resistance (basal EGP × fasting plasma insulin) were determined. RESULTS After 2 wk of exenatide (protocol I), fasting plasma glucose decreased (from 10.2 to 7.6 mm) and mean postmeal plasma glucose decreased (from 13.2 to 11.3 mm) (P < 0.05); fasting and meal-stimulated plasma insulin and glucagon did not change significantly. After exenatide, basal EGP decreased (from 13.9 to 10.8 μmol/kg · min, P < 0.05), and hepatic insulin resistance declined (both P < 0.05). RaO, gastric emptying (acetaminophen area under the curve), and splanchnic glucose uptake did not change. In protocol II (exenatide given before repeat meal), fasting plasma glucose decreased (from 11.1 to 8.9 mm) and mean postmeal plasma glucose decreased (from 14.2 to 10.1 mm) (P < 0.05); fasting and meal-stimulated plasma insulin and glucagon did not change significantly. After exenatide, basal EGP decreased (from 13.4 to 10.7 μmol/kg · min, P = 0.05). RaT and RaO decreased markedly from 0-180 min after meal ingestion, consistent with exenatide's action to delay gastric emptying. CONCLUSIONS Exenatide improves 1) fasting hyperglycemia by reducing basal EGP and 2) postmeal hyperglycemia by reducing the appearance of oral glucose in the systemic circulation.
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Affiliation(s)
- E Cersosimo
- Division of Diabetes, Department of Medicine, University of Texas Health Science Center, San Antonio, Texas 78229, USA
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Ayala JE, Bracy DP, James FD, Burmeister MA, Wasserman DH, Drucker DJ. Glucagon-like peptide-1 receptor knockout mice are protected from high-fat diet-induced insulin resistance. Endocrinology 2010; 151:4678-87. [PMID: 20685876 PMCID: PMC2946144 DOI: 10.1210/en.2010-0289] [Citation(s) in RCA: 65] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Glucagon-like peptide-1 augments nutrient-stimulated insulin secretion. Chow-fed mice lacking the glucagon-like peptide-1 receptor (Glp1r) exhibit enhanced insulin-stimulated muscle glucose uptake but impaired suppression of endogenous glucose appearance (endoRa). This proposes a novel role for the Glp1r to regulate the balance of glucose disposal in muscle and liver by modulating insulin action. Whether this is maintained in an insulin-resistant state is unknown. The present studies tested the hypothesis that disruption of Glp1r expression overcomes high-fat (HF) diet-induced muscle insulin resistance and exacerbates HF diet-induced hepatic insulin resistance. Mice with a functional disruption of the Glp1r (Glp1r-/-) were compared with wild-type littermates (Glp1r+/+) after 12 wk on a regular chow diet or a HF diet. Arterial and venous catheters were implanted for sampling and infusions. Hyperinsulinemic-euglycemic clamps were performed on weight-matched male mice. [3-(3)H]glucose was used to determine glucose turnover, and 2[14C]deoxyglucose was used to measure the glucose metabolic index, an indicator of glucose uptake. Glp1r-/- mice exhibited increased glucose disappearance and muscle glucose metabolic index on either diet. This was associated with enhanced activation of muscle Akt and AMP-activated protein kinase and reduced muscle triglycerides in HF-fed Glp1r-/- mice. Chow-fed Glp1r-/- mice exhibited impaired suppression of endoRa and hepatic insulin signaling. In contrast, HF-fed Glp1r-/- mice exhibited improved suppression of endoRa and hepatic Akt activation. This was associated with decreased hepatic triglycerides and impaired activation of sterol regulatory element-binding protein-1. These results show that mice lacking the Glp1r are protected from HF diet-induced muscle and hepatic insulin resistance independent of effects on total fat mass.
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Affiliation(s)
- Julio E Ayala
- Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, Tennessee 37232, USA.
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Preumont V, Hermans MP, Brichard S, Buysschaert M. Six-month exenatide improves HOMA hyperbolic product in type 2 diabetic patients mostly by enhancing beta-cell function rather than insulin sensitivity. DIABETES & METABOLISM 2010; 36:293-8. [DOI: 10.1016/j.diabet.2010.02.001] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2009] [Revised: 02/03/2010] [Accepted: 02/05/2010] [Indexed: 11/28/2022]
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Dalla Man C, Micheletto F, Sathananthan A, Rizza RA, Vella A, Cobelli C. A model of GLP-1 action on insulin secretion in nondiabetic subjects. Am J Physiol Endocrinol Metab 2010; 298:E1115-21. [PMID: 20179243 PMCID: PMC2886533 DOI: 10.1152/ajpendo.00705.2009] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Glucagon-like peptide-1 (GLP-1)-based therapies for diabetes have aroused interest because of their effects on insulin secretion and glycemic control. However, a mechanistic model enabling quantitation of pancreatic response to GLP-1 has never been developed. To develop such a model we studied 88 healthy individuals (age 26.3 +/- 0.6 yr, BMI 24.9 +/- 0.4 kg/m(2)) by use of a hyperglycemic clamp. A variable infusion maintained glucose concentrations at 150 mg/dl for 240 min. At 120 min, an intravenous infusion of GLP-1 was started (0.75 pmol kg(-1) min(-1) from 120-180 min, 1.5 pmol kg(-1) min(-1) from 181-240 min). Consequently, plasma C-peptide concentration rose from 1,852.0 +/- 62.8 pmol/l at 120 min to 4,272.2 +/- 176.4 pmol/l at 180 min and to 6,995.8 +/- 323.5 pmol/l at 240 min. Four models of GLP-1 action on insulin secretion were considered. All models share the common assumption that insulin secretion is made up of two components, one proportional to glucose rate of change through dynamic responsivity, Phi(d), and one proportional to glucose through static responsivity, Phi(s), but differing by modality of GLP-1 control. The model that best fit C-peptide data assumes that above-basal insulin secretion depends linearly on GLP-1 concentration and its rate of change. An index (Pi) measuring the percentage increase of secretion due to GLP-1 is derived. Before GLP-1 infusion, Phi(d) = 245.7 +/- 15.6 10(-9) and Phi(s) = 25.2 +/- 1.4 10(-9) min(-1). Under GLP-1 stimulus, Pi = 12.6 +/- 0.71% per pmol/l, meaning that an increase of 5 pmol/l in peripheral GLP-1 concentrations induces an approximately 60% increase in over-basal insulin secretion.
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Affiliation(s)
- Chiara Dalla Man
- Department of Information Engineering, University of Padova, Padua, Italy
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