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Jin FX, Wang Y, Li MN, Li RJ, Guo JT. Intestinal glucagon-like peptide-1: A new player associated with impaired counterregulatory responses to hypoglycaemia in type 1 diabetic mice. World J Diabetes 2024; 15:1764-1777. [DOI: 10.4239/wjd.v15.i8.1764] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Revised: 06/03/2024] [Accepted: 07/05/2024] [Indexed: 07/25/2024] Open
Abstract
BACKGROUND Impaired hypoglycaemic counterregulation has emerged as a critical concern for diabetic patients who may be hesitant to medically lower their blood glucose levels due to the fear of potential hypoglycaemic reactions. However, the patho-genesis of hypoglycaemic counterregulation is still unclear. Glucagon-like peptide-1 (GLP-1) and its analogues have been used as adjunctive therapies for type 1 diabetes mellitus (T1DM). The role of GLP-1 in counterregulatory dys-function during hypoglycaemia in patients with T1DM has not been reported.
AIM To explore the impact of intestinal GLP-1 on impaired hypoglycaemic counterregulation in type 1 diabetic mice.
METHODS T1DM was induced in C57BL/6J mice using streptozotocin, followed by intraperitoneal insulin injections to create T1DM models with either a single episode of hypoglycaemia or recurrent episodes of hypoglycaemia (DH5). Immunofluorescence, Western blot, and enzyme-linked immunosorbent assay were employed to evaluate the influence of intestinal GLP-1 on the sympathetic-adrenal reflex and glucagon (GCG) secretion. The GLP-1 receptor agonist GLP-1(7-36) or the antagonist exendin (9-39) were infused into the terminal ileum or injected intraperitoneally to further investigate the role of intestinal GLP-1 in hypoglycaemic counterregulation in the model mice.
RESULTS The expression levels of intestinal GLP-1 and its receptor (GLP-1R) were significantly increased in DH5 mice. Consecutive instances of excess of intestinal GLP-1 weakens the sympathetic-adrenal reflex, leading to dysfunction of adrenal counterregulation during hypoglycaemia. DH5 mice showed increased pancreatic δ-cell mass, cAMP levels in δ cells, and plasma somatostatin concentrations, while cAMP levels in pancreatic α cells and plasma GCG levels decreased. Furthermore, GLP-1R expression in islet cells and plasma active GLP-1 levels were significantly increased in the DH5 group. Further experiments involving terminal ileal infusion and intraperitoneal injection in the model mice demonstrated that intestinal GLP-1 during recurrent hypoglycaemia hindered the secretion of the counterregulatory hormone GCG via the endocrine pathway.
CONCLUSION Excessive intestinal GLP-1 is strongly associated with impaired counterregulatory responses to hypoglycaemia, leading to reduced appetite and compromised secretion of adrenaline, noradrenaline, and GCG during hypo-glycaemia.
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Affiliation(s)
- Fang-Xin Jin
- Department of Histology and Embryology, Key Laboratory of Universities in Shandong Province, Shandong Second Medical University, Weifang 261053, Shandong Province, China
| | - Yan Wang
- Department of Histology and Embryology, Key Laboratory of Universities in Shandong Province, Shandong Second Medical University, Weifang 261053, Shandong Province, China
| | - Min-Ne Li
- Department of Histology and Embryology, Key Laboratory of Universities in Shandong Province, Shandong Second Medical University, Weifang 261053, Shandong Province, China
| | - Ru-Jiang Li
- Department of Histology and Embryology, Key Laboratory of Universities in Shandong Province, Shandong Second Medical University, Weifang 261053, Shandong Province, China
| | - Jun-Tang Guo
- Department of Pathological Physiology, Shandong Second Medical University, Weifang 261053, Shandong Province, China
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2
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Zhao S, Wang Z, Qing P, Li M, Liu Q, Pang X, Wang K, Gao X, Zhao J, Wu Y. Comprehensive analysis of the association between triglyceride-glucose index and coronary artery disease severity across different glucose metabolism states: a large-scale cross-sectional study from an Asian cohort. Cardiovasc Diabetol 2024; 23:251. [PMID: 39003471 PMCID: PMC11245858 DOI: 10.1186/s12933-024-02355-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Accepted: 07/08/2024] [Indexed: 07/15/2024] Open
Abstract
BACKGROUND The triglyceride-glucose (TyG) index is associated with the development and prognosis of coronary artery disease (CAD). However, the impact of the TyG index on CAD severity across different glucose metabolism states exhibits significant disparities in previous research. METHODS This cross-sectional study comprised 10,433 participants from a prospective cohort. Participants were categorized into four groups based on glucose metabolism state: normal glucose regulation (NGR), prediabetes (pre-DM), diabetes mellitus (DM) without insulin prescribed (Rx), and DM with insulin Rx. The TyG index was determined by the following formula: Ln [TG (mg/dL) × FPG (mg/dL) / 2], where TG is triglycerides and FPG is fasting plasm glucose. Statistical methods such as binary logistic regression, interaction analysis, restricted cubic spline (RCS), and receiver operating characteristic (ROC) were employed to analyze the relationship between the TyG index and CAD severity across the entire population and glucose metabolism subgroups. Mediation analysis was conducted to examine the mediating effects of glycated hemoglobin (HbA1c) on these relationships. Sensitivity analysis was performed to ensure the robustness of the findings. RESULTS Multivariable logistic regression analysis revealed a significant positive association between the TyG index and multi-vessel CAD in the entire population (OR: 1.34; 95% CI: 1.22-1.47 per 1-unit increment). Subgroup analysis demonstrated consistent positive associations in the NGR, pre-DM, and DM non-insulin Rx groups, with the highest OR observed in the NGR group (OR: 1.67; 95% CI: 1.3-2.14 per 1-unit increment). No correlation was found in the DM with insulin Rx subgroup. RCS analyses indicated the distinct dose-response relationships across different glucose metabolism subgroups. Including the TyG index in the established model slightly improved the predictive accuracy, particularly in the NGR group. Mediation analyses showed varying mediating effects of HbA1c among different glucose metabolism subgroups. Sensitivity analysis confirmed the robustness of the aforementioned relationships in the new-onset CAD population and in individuals not using antilipidemic medications. CONCLUSIONS The TyG index positively associated with CAD severity across all glucose metabolism states, except for individuals receiving insulin treatment. Moreover, it might serve as a supplementary noninvasive predictor of CAD severity in addition to established factors, especially in NGR patients.
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Affiliation(s)
- Sheng Zhao
- Department of Cardiology, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Zuoxiang Wang
- Department of Cardiology, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Ping Qing
- Department of Cardiology, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Minghui Li
- Department of Cardiology, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China
| | - Qingrong Liu
- Department of Cardiology, Beijing Aerospace General Hospital, Beijing, China
| | - Xuejie Pang
- Department of Respiratory and Critical Care, Chinese PLA General Hospital, the First Medical Centre, Beijing, China
| | - Keke Wang
- Department of Cardiology, Chinese PLA General Hospital, the Second Medical Centre, Beijing, China
| | - Xiaojin Gao
- Department of Cardiology, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, No.167 North Lishi Road, Xicheng District, 100037, Beijing, China.
| | - Jie Zhao
- Department of Cardiology, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, No.167 North Lishi Road, Xicheng District, 100037, Beijing, China.
| | - Yongjian Wu
- Department of Cardiology, State Key Laboratory of Cardiovascular Disease, National Center for Cardiovascular Diseases, Fuwai Hospital, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, China.
- State Key Laboratory of Cardiovascular Disease, Fuwai Hospital, National Center for Cardiovascular Disease, Chinese Academy of Medical Sciences and Peking Union Medical College, No.167 North Lishi Road, Xicheng District, 100037, Beijing, China.
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3
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Makanyane DM, Maikoo S, Van Heerden FR, Rhyman L, Ramasami P, Mabuza LP, Ngubane P, Khathi A, Mambanda A, Booysen IN. Bovine serum albumin uptake and polypeptide disaggregation studies of hypoglycemic ruthenium(II) uracil Schiff-base complexes. J Inorg Biochem 2024; 255:112541. [PMID: 38554578 DOI: 10.1016/j.jinorgbio.2024.112541] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2023] [Revised: 02/13/2024] [Accepted: 03/22/2024] [Indexed: 04/01/2024]
Abstract
Our prior studies have illustrated that the uracil ruthenium(II) diimino complex, [Ru(H3ucp)Cl(PPh3)] (1) (H4ucp = 2,6-bis-((6-amino-1,3-dimethyluracilimino)methylene)pyridine) displayed high hypoglycemic effects in diet-induced diabetic rats. To rationalize the anti-diabetic effects of 1, three new derivatives have been prepared, cis-[Ru(bpy)2(urdp)]Cl2 (2) (urdp = 2,6-bis-((uracilimino)methylene)pyridine), trans-[RuCl2(PPh3)(urdp)] (3), and cis-[Ru(bpy)2(H4ucp)](PF6)2 (4). Various physicochemical techniques were utilized to characterize the structures of the novel ruthenium compounds. Prior to biomolecular interactions or in vitro studies, the stabilities of 1-4 were monitored in anhydrous DMSO, aqueous phosphate buffer containing 2% DMSO, and dichloromethane (DCM) via UV-Vis spectrophotometry. Time-dependent stability studies showed ligand exchange between DMSO nucleophiles and chloride co-ligands of 1 and 3, which was suppressed in the presence of an excess amount of chloride ions. In addition, the metal complexes 1 and 3 are stable in both DCM and an aqueous phosphate buffer containing 2% DMSO. In the case of compounds 2 and 4 with no chloride co-ligands within their coordination spheres, high stability in aqueous phosphate buffer containing 2% DMSO was observed. Fluorescence emission titrations of the individual ruthenium compounds with bovine serum albumin (BSA) showed that the metal compounds interact non-discriminately within the protein's hydrophobic cavities as moderate to strong binders. The metal complexes were capable of disintegrating mature amylin amyloid fibrils. In vivo glucose metabolism studies in liver (Chang) cell lines confirmed enhanced glucose metabolism as evidenced by the increased glucose utilization and glycogen synthesis in liver cell lines in the presence of complexes 2-4.
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Affiliation(s)
- Daniel M Makanyane
- School of Chemistry and Physics, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Sanam Maikoo
- School of Chemistry and Physics, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Fanie R Van Heerden
- School of Chemistry and Physics, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Lydia Rhyman
- Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit 80837, Mauritius; Centre of Natural Product, Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa
| | - Ponnadurai Ramasami
- Computational Chemistry Group, Department of Chemistry, Faculty of Science, University of Mauritius, Réduit 80837, Mauritius; Centre of Natural Product, Department of Chemical Sciences, University of Johannesburg, Doornfontein, Johannesburg 2028, South Africa
| | - Lindokuhle P Mabuza
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa.
| | - Phikelelani Ngubane
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Andile Khathi
- School of Laboratory Medicine and Medical Sciences, University of KwaZulu-Natal, Durban, South Africa
| | - Allen Mambanda
- School of Chemistry and Physics, University of KwaZulu-Natal, Pietermaritzburg, South Africa
| | - Irvin N Booysen
- School of Chemistry and Physics, University of KwaZulu-Natal, Pietermaritzburg, South Africa.
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4
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Hashsham A, Kodur N, Su J, Tomlinson AJ, Yacawych WT, Flak JN, Lewis KT, Oles LR, Mori H, Bozadjieva-Kramer N, Turcu AF, MacDougald OA, Myers MG, Affinati AH. Control of Physiologic Glucose Homeostasis via the Hypothalamic Modulation of Gluconeogenic Substrate Availability. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.05.20.594873. [PMID: 38826340 PMCID: PMC11142065 DOI: 10.1101/2024.05.20.594873] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2024]
Abstract
The brain augments glucose production during fasting, but the mechanisms are poorly understood. Here, we show that Cckbr-expressing neurons in the ventromedial hypothalamic nucleus (VMNCckbr cells) prevent low blood glucose during fasting through sympathetic nervous system (SNS)-mediated augmentation of adipose tissue lipolysis and substrate release. Activating VMNCckbr neurons mobilized gluconeogenic substrates without altering glycogenolysis or gluconeogenic enzyme expression. Silencing these cells (CckbrTetTox animals) reduced fasting blood glucose, impaired lipolysis, and decreased circulating glycerol (but not other gluconeogenic substrates) despite normal insulin, counterregulatory hormones, liver glycogen, and liver gluconeogenic gene expression. Furthermore, β3-adrenergic adipose tissue stimulation in CckbrTetTox animals restored lipolysis and blood glucose. Hence, VMNCckbr neurons impact blood glucose not by controlling islet or liver physiology, but rather by mobilizing gluconeogenic substrates. These findings establish a central role for hypothalamic and SNS signaling during normal glucose homeostasis and highlight the importance of gluconeogenic substrate mobilization during physiologic fasting.
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Affiliation(s)
- Abdullah Hashsham
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Nandan Kodur
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Jiaao Su
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | | | - Warren T. Yacawych
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Jon N. Flak
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Kenneth T. Lewis
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Lily R. Oles
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Hiroyuki Mori
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Nadejda Bozadjieva-Kramer
- Veterans Affairs Ann Arbor Healthcare System; Research Service, Ann Arbor, MI
- University of Michigan, Department of Surgery; Ann Arbor, MI
| | - Adina F. Turcu
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
| | - Ormond A. MacDougald
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
| | - Martin G. Myers
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI
- Department of Molecular & Integrative Physiology, University of Michigan, Ann Arbor, MI
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5
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Modestino MR, Iacono O, Ferrentino L, Lombardi A, De Fortuna U, Verdoliva R, De Luca M, Guardasole V. How should we differentiate hypoglycaemia in non-diabetic patients? J Basic Clin Physiol Pharmacol 2024; 35:111-119. [PMID: 38619602 DOI: 10.1515/jbcpp-2024-0030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2024] [Accepted: 03/10/2024] [Indexed: 04/16/2024]
Abstract
Hypoglycaemic syndromes are rare in apparently healthy individuals and their diagnosis can be a difficult challenge for clinicians as there are no shared guidelines that suggest how to approach patients with a suspect hypoglycaemic disorder. Since hypoglycaemia symptoms are common and nonspecific, it's necessary to document the Whipple Triad (signs and/or symptoms compatible with hypoglycaemia; relief of symptoms following glucose administration; low plasma glucose levels) before starting any procedure. Once the triad is documented, a meticulous anamnesis and laboratory tests (blood glucose, insulin, proinsulin, C-peptide, β-hydroxybutyrate and anti-insulin antibodies) should be performed. Results can guide the physician towards further specific tests, concerning the suspected disease. In this review, we consider all current causes of hypoglycaemia, including rare diseases such as nesidioblastosis and Hirata's syndrome, describe appropriate tests for diagnosis and suggest strategies to differentiate hypoglycaemia aetiology.
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Affiliation(s)
- Michele R Modestino
- Department of Translational Medical Sciences, 165474 Federico II University Hospital , Napoli, Italy
| | - Olimpia Iacono
- Department of Translational Medical Sciences, 165474 Federico II University Hospital , Napoli, Italy
| | - Laura Ferrentino
- Department of Translational Medical Sciences, 165474 Federico II University Hospital , Napoli, Italy
| | - Anna Lombardi
- Department of Translational Medical Sciences, 165474 Federico II University Hospital , Napoli, Italy
| | - Umberto De Fortuna
- Department of Translational Medical Sciences, 165474 Federico II University Hospital , Napoli, Italy
| | - Rita Verdoliva
- Department of Translational Medical Sciences, 165474 Federico II University Hospital , Napoli, Italy
| | - Mariarosaria De Luca
- Department of Translational Medical Sciences, 165474 Federico II University Hospital , Napoli, Italy
| | - Vincenzo Guardasole
- Department of Translational Medical Sciences, 165474 Federico II University Hospital , Napoli, Italy
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6
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Damm J, Aureli F, Rangel-Negrín A, Barradas-Moctezuma M, Dias PAD. Analytical and biological validation of a noninvasive measurement of glucocorticoid metabolites in feces of Geoffroy's spider monkeys (Ateles geoffroyi). Am J Primatol 2024; 86:e23598. [PMID: 38258612 DOI: 10.1002/ajp.23598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2023] [Revised: 12/21/2023] [Accepted: 01/06/2024] [Indexed: 01/24/2024]
Abstract
We report on an analytical and biological validation of a commercial cortisol enzyme immunoassay (EIA) to measure glucocorticoids (GC) in feces of Geoffroy's spider monkeys (Ateles geoffroyi). Validation of endocrinological methods for each sample matrix and study species is crucial to establish that the methods produce reliable results. For the analytical validation of the EIA, we assessed parallelism, accuracy, and precision. We carried out a biological validation based on three well-studied GC patterns with the following predictions: (1) increased fecal GC metabolite (fGCM) concentrations after veterinary intervention; (2) increased fGCM concentrations during early morning hours; and (3) higher fGCM concentrations during gestation than in other female reproductive states. For the first prediction, we sampled feces of two zoo-housed females 2 days before, the day of, and 2 days after a veterinary intervention. For the second prediction, we analyzed 284 fecal samples collected from 12 wild males using a linear mixed model (LMM). For the third prediction, we analyzed 269 fecal samples of eight wild females using an LMM. Analytical validation revealed that the EIA showed parallelism, was accurate, and precise within each assay. However, there was elevated variation in between-assay precision. The biological validation supported all predictions: (1) the two zoo-housed females showed a substantial increase in fGCM concentrations 2.5 and 11 h after veterinary intervention; (2) there was a negative effect of sample collection time on fGCM concentrations (i.e., higher concentrations during early morning); (3) gestating females had significantly higher fGCM concentrations than lactating females. Thus, we analytically validated the commercial EIA and, despite between-assay variation, we were able to find three biologically relevant GC signals in captive and wild settings, and in males and females. We are therefore confident that the method can be used to noninvasively address behavioral endocrinology questions in Geoffroy's spider monkeys.
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Affiliation(s)
- Juliane Damm
- Instituto de Neuroetología, Universidad Veracruzana, Xalapa, Mexico
| | - Filippo Aureli
- Instituto de Neuroetología, Universidad Veracruzana, Xalapa, Mexico
- Research Centre in Evolutionary Anthropology and Palaeoecology, Liverpool John Moores University, Liverpool, UK
| | - Ariadna Rangel-Negrín
- Instituto de Neuroetología, Universidad Veracruzana, Xalapa, Mexico
- Primate Behavioral Ecology Lab, Instituto de Neuro-etología, Universidad Veracruzana, Xalapa, Mexico
| | | | - Pedro A D Dias
- Primate Behavioral Ecology Lab, Instituto de Neuro-etología, Universidad Veracruzana, Xalapa, Mexico
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7
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Salman UA, Schwartz JG, McMahan AC, Michalek JE, Phillips WT. Rapid Gastric emptying in spontaneously hypertensive rats. J Hypertens 2024; 42:572-578. [PMID: 38088427 DOI: 10.1097/hjh.0000000000003640] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2024]
Abstract
OBJECTIVE To assess the rate of gastric emptying in spontaneously hypertensive rats (SHR) and to evaluate rapid gastric emptying as a possible predisposing factor for hypertension. Rapid gastric emptying of carbohydrates, known to elevate postprandial serum glucose, has been reported to occur in many insulin-resistant states, including hypertension. SHR exhibit insulin resistance similar to human hypertensive patients. No prior studies have assessed gastric emptying of an oral glucose solution in SHR as compared with control Wistar Kyoto rats (WKY). METHODS Using scintigraphic imaging, gastric emptying of a physiologic, orally consumed glucose solution was assessed in 12 SHR and 12 control WKY at 5 weeks of age, prior to the development of hypertension, and at 12 weeks of age after hypertension was fully established. RESULTS At 5 weeks, the gastric half-emptying time (GHET) was 67.8 ± 9.8 min for the SHR vs. 109.3 ± 18 ( P = 0.042) minutes for the WKY controls. At 12 weeks, the GHET was 37.29 ± 10.3 min for the SHR vs. 138.53 ± 37.6 ( P = 0.016) min for the WKY controls. CONCLUSION Gastric emptying was significantly more rapid in the SHR before and after the development of hypertension. Even though SHR are known to have increased sympathetic activity associated with their development of hypertension, this increased sympathetic activity does not inhibit gastric emptying. SHR are a promising animal model for investigating therapeutic agents for treating hypertension aimed at slowing the rate of gastric emptying.
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Affiliation(s)
| | | | | | - Joel E Michalek
- Department of Population Health Sciences, UT Health San Antonio, San Antonio, Texas, USA
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8
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D’Souza NC, Aiken JA, Hoffman EG, Atherley SC, Champsi S, Aleali N, Shakeri D, El-Zahed M, Akbarian N, Nejad-Mansouri M, Bavani PZ, Liggins RL, Chan O, Riddell MC. Evaluating the effectiveness of a novel somatostatin receptor 2 antagonist, ZT-01, for hypoglycemia prevention in a rodent model of type 2 diabetes. Front Pharmacol 2024; 15:1302015. [PMID: 38510652 PMCID: PMC10951717 DOI: 10.3389/fphar.2024.1302015] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2023] [Accepted: 01/29/2024] [Indexed: 03/22/2024] Open
Abstract
Background: Elevated levels of somatostatin blunt glucagon counterregulation during hypoglycemia in type 1 diabetes (T1D) and this can be improved using somatostatin receptor 2 (SSTR2) antagonists. Hypoglycemia also occurs in late-stage type 2 diabetes (T2D), particularly when insulin therapy is initiated, but the utility of SSTR2 antagonists in ameliorating hypoglycemia in this disease state is unknown. We examined the efficacy of a single-dose of SSTR2 antagonists in a rodent model of T2D. Methods: High-fat fed (HFF), low dose streptozotocin (STZ, 35 mg/kg)-induced T2D and HFF only, nondiabetic (controls-no STZ) rats were treated with the SSTR2 antagonists ZT-01/PRL-2903 or vehicle (n = 9-11/group) 60 min before an insulin tolerance test (ITT; 2-12 U/kg insulin aspart) or an oral glucose tolerance test (OGTT; 2 g/kg glucose via oral gavage) on separate days. Results: This rodent model of T2D is characterized by higher baseline glucose and HbA1c levels relative to HFF controls. T2D rats also had lower c-peptide levels at baseline and a blunted glucagon counterregulatory response to hypoglycemia when subjected to the ITT. SSTR2 antagonists increased the glucagon response and reduced incidence of hypoglycemia, which was more pronounced with ZT-01 than PRL-2903. ZT-01 treatment in the T2D rats increased glucagon levels above the control response within 60 min of dosing, and values remained elevated during the ITT (glucagon Cmax: 156 ± 50 vs. 77 ± 46 pg/mL, p < 0.01). Hypoglycemia incidence was attenuated with ZT-01 vs. controls (63% vs. 100%) and average time to hypoglycemia onset was also delayed (103.1 ± 24.6 vs. 66.1 ± 23.6 min, p < 0.05). ZT-01 administration at the OGTT onset increased the glucagon response without exacerbating hyperglycemia (2877 ± 806 vs. 2982 ± 781), potentially due to the corresponding increase in c-peptide levels (6251 ± 5463 vs. 14008 ± 5495, p = 0.013). Conclusion: Treatment with SSTR2 antagonists increases glucagon responses in a rat model of T2D and results in less hypoglycemia exposure. Future studies are required to determine the best dosing periods for chronic SSTR2 antagonism treatment in T2D.
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Affiliation(s)
| | - Julian A. Aiken
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Emily G. Hoffman
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Sara C. Atherley
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Sabrina Champsi
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Nadia Aleali
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Dorsa Shakeri
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Maya El-Zahed
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | - Nicky Akbarian
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | | | - Parinaz Z. Bavani
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
| | | | - Owen Chan
- Department of Internal Medicine, Division of Endocrinology, University of Utah, Salt LakeCity, UT, United States
| | - Michael C. Riddell
- School of Kinesiology and Health Science, York University, Toronto, ON, Canada
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9
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Varkevisser RDM, Cecil A, Prehn C, Mul D, Aanstoot HJ, Paterson AD, Wolffenbuttel BHR, van der Klauw MM. Metabolomic associations of impaired awareness of hypoglycaemia in type 1 diabetes. Sci Rep 2024; 14:4485. [PMID: 38396205 PMCID: PMC10891160 DOI: 10.1038/s41598-024-55032-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2023] [Accepted: 02/19/2024] [Indexed: 02/25/2024] Open
Abstract
This study investigates impaired awareness of hypoglycaemia (IAH), a complication of insulin therapy affecting 20-40% of individuals with type 1 diabetes. The exact pathophysiology is unclear, therefore we sought to identify metabolic signatures in IAH to elucidate potential pathophysiological pathways. Plasma samples from 578 individuals of the Dutch type 1 diabetes biomarker cohort, 67 with IAH and 108 without IAH (NAH) were analysed using the targeted metabolomics Biocrates AbsoluteIDQ p180 assay. Eleven metabolites were significantly associated with IAH. Genome-wide association studies of these 11 metabolites identified significant single nucleotide polymorphisms (SNPs) in C22:1-OH and phosphatidylcholine diacyl C36:6. After adjusting for the SNPs, 11 sphingomyelins and phosphatidylcholines were significantly higher in the IAH group in comparison to NAH. These metabolites are important components of the cell membrane and have been implicated to play a role in cell signalling in diabetes. These findings demonstrate the potential role of phosphatidylcholine and sphingomyelins in IAH.
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Affiliation(s)
- R D M Varkevisser
- Department of Endocrinology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands.
| | - A Cecil
- Metabolomic and Proteomics Core, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - C Prehn
- Metabolomic and Proteomics Core, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - D Mul
- Diabeter Netherlands, Center for Type 1 Diabetes Care and Research, Rotterdam, The Netherlands
| | - H J Aanstoot
- Diabeter Netherlands, Center for Type 1 Diabetes Care and Research, Rotterdam, The Netherlands
| | - A D Paterson
- Genetics and Genome Biology Program, The Hospital for Sick Children, Toronto, Canada
- Divisions of Epidemiology and Biostatistics, Dalla Lana School of Public Health, University of Toronto, Toronto, Canada
| | - B H R Wolffenbuttel
- Department of Endocrinology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
| | - M M van der Klauw
- Department of Endocrinology, University of Groningen, University Medical Center Groningen, Groningen, The Netherlands
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10
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Li C, Ma Y, Chai X, Feng X, Feng W, Zhao Y, Cui C, Wang J, Zhao S, Zhu X. Ketogenic diet attenuates cognitive dysfunctions induced by hypoglycemia via inhibiting endoplasmic reticulum stress-dependent pathways. Food Funct 2024; 15:1294-1309. [PMID: 38197246 DOI: 10.1039/d3fo04007k] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Hypoglycemia can potentially cause severe damage to the central nervous system. The ketogenic diet (KD), characterized by high-fat and extremely low-carbohydrate content, can modulate homeostasis and nutrient metabolism, thereby influencing body health. However, the effects and underlying mechanisms of KD on hypoglycemia-induced brain injury have not been thoroughly investigated. We aimed to explore the modulating effects of KD on cognitive functions and elucidate the underlying mechanisms. In this study, one-month-old mice were fed with KD for 2 weeks, and the changes in the gut microbiota were detected using the 16S rRNA gene amplicon sequencing method. The hypoglycemic model of mice was established using insulin, and the potential protective effect of KD on hypoglycemia-induced brain injury in mice was evaluated through immunofluorescence staining, western blotting, transmission electron microscopy, and Golgi staining. Our results showed that the intestinal flora of Dorea increased and Rikenella decreased in KD-fed mice. KD can not only alleviate anxiety-like behavior induced by hypoglycemia, but also increase the proportion of mushroom dendritic spines in the hippocampus by modulating changes in the gut microbiota. KD regulated synaptic plasticity by increasing the levels of SPN, PSD95, and SYP, which relieve cognitive impairment caused by hypoglycemia. Moreover, KD can promote the proliferation and survival of adult neural stem cells in the hippocampus, while reducing apoptosis by suppressing the activation of the IRE1-XBP1 and ATF6 endoplasmic reticulum stress pathways in mice with hypoglycemia. This study provides new evidence for demonstrating that KD may alleviate cognitive dysfunctions caused by hypoglycemia by modulating the gut microbiota.
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Affiliation(s)
- Cixia Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
- College of Life Science and Technology, Xinxiang Medical University, Xinxiang, Henan 453003, PR China
- Henan Key Laboratory of Medical Tissue Regeneration, Xinxiang Medical University, Xinxiang, Henan 453003, PR China
| | - Yue Ma
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
| | - Xuejun Chai
- College of Basic Medicine, Xi'An Medical University, Xi'An, Shaanxi 710021, PR China
| | - Xiao Feng
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
| | - Wenyu Feng
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
| | - Yongkang Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
| | - Chaochu Cui
- Henan Key Laboratory of Medical Tissue Regeneration, Xinxiang Medical University, Xinxiang, Henan 453003, PR China
| | - Jianguo Wang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
| | - Shanting Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
| | - Xiaoyan Zhu
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi 712100, PR China.
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11
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Castillo-Armengol J, Marzetta F, Rodriguez Sanchez-Archidona A, Fledelius C, Evans M, McNeilly A, McCrimmon RJ, Ibberson M, Thorens B. Disrupted hypothalamic transcriptomics and proteomics in a mouse model of type 2 diabetes exposed to recurrent hypoglycaemia. Diabetologia 2024; 67:371-391. [PMID: 38017352 PMCID: PMC10789691 DOI: 10.1007/s00125-023-06043-x] [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: 04/18/2023] [Accepted: 09/07/2023] [Indexed: 11/30/2023]
Abstract
AIMS/HYPOTHESIS Repeated exposures to insulin-induced hypoglycaemia in people with diabetes progressively impairs the counterregulatory response (CRR) that restores normoglycaemia. This defect is characterised by reduced secretion of glucagon and other counterregulatory hormones. Evidence indicates that glucose-responsive neurons located in the hypothalamus orchestrate the CRR. Here, we aimed to identify the changes in hypothalamic gene and protein expression that underlie impaired CRR in a mouse model of defective CRR. METHODS High-fat-diet fed and low-dose streptozocin-treated C57BL/6N mice were exposed to one (acute hypoglycaemia [AH]) or multiple (recurrent hypoglycaemia [RH]) insulin-induced hypoglycaemic episodes and plasma glucagon levels were measured. Single-nuclei RNA-seq (snRNA-seq) data were obtained from the hypothalamus and cortex of mice exposed to AH and RH. Proteomic data were obtained from hypothalamic synaptosomal fractions. RESULTS The final insulin injection resulted in similar plasma glucose levels in the RH group and AH groups, but glucagon secretion was significantly lower in the RH group (AH: 94.5±9.2 ng/l [n=33]; RH: 59.0±4.8 ng/l [n=37]; p<0.001). Analysis of snRNA-seq data revealed similar proportions of hypothalamic cell subpopulations in the AH- and RH-exposed mice. Changes in transcriptional profiles were found in all cell types analysed. In neurons from RH-exposed mice, we observed a significant decrease in expression of Avp, Pmch and Pcsk1n, and the most overexpressed gene was Kcnq1ot1, as compared with AH-exposed mice. Gene ontology analysis of differentially expressed genes (DEGs) indicated a coordinated decrease in many oxidative phosphorylation genes and reduced expression of vacuolar H+- and Na+/K+-ATPases; these observations were in large part confirmed in the proteomic analysis of synaptosomal fractions. Compared with AH-exposed mice, oligodendrocytes from RH-exposed mice had major changes in gene expression that suggested reduced myelin formation. In astrocytes from RH-exposed mice, DEGs indicated reduced capacity for neurotransmitters scavenging in tripartite synapses as compared with astrocytes from AH-exposed mice. In addition, in neurons and astrocytes, multiple changes in gene expression suggested increased amyloid beta (Aβ) production and stability. The snRNA-seq analysis of the cortex showed that the adaptation to RH involved different biological processes from those seen in the hypothalamus. CONCLUSIONS/INTERPRETATION The present study provides a model of defective counterregulation in a mouse model of type 2 diabetes. It shows that repeated hypoglycaemic episodes induce multiple defects affecting all hypothalamic cell types and their interactions, indicative of impaired neuronal network signalling and dysegulated hypoglycaemia sensing, and displaying features of neurodegenerative diseases. It also shows that repeated hypoglycaemia leads to specific molecular adaptation in the hypothalamus when compared with the cortex. DATA AVAILABILITY The transcriptomic dataset is available via the GEO ( http://www.ncbi.nlm.nih.gov/geo/ ), using the accession no. GSE226277. The proteomic dataset is available via the ProteomeXchange data repository ( http://www.proteomexchange.org ), using the accession no. PXD040183.
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Affiliation(s)
- Judit Castillo-Armengol
- Novo Nordisk A/S, Måløv, Denmark
- Center for Integrative Genomics (CIG), University of Lausanne, Lausanne, Switzerland
| | - Flavia Marzetta
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | | | | | - Mark Evans
- IMS Metabolic Research Laboratories, Addenbrookes Biomedical Campus, Cambridge, UK
| | | | | | - Mark Ibberson
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics (CIG), University of Lausanne, Lausanne, Switzerland.
- Vital-IT Group, SIB Swiss Institute of Bioinformatics, Lausanne, Switzerland.
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12
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Senthilkumaran M, Koch C, Herselman MF, Bobrovskaya L. Role of the Adrenal Medulla in Hypoglycaemia-Associated Autonomic Failure-A Diabetic Perspective. Metabolites 2024; 14:100. [PMID: 38392992 PMCID: PMC10890365 DOI: 10.3390/metabo14020100] [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: 12/30/2023] [Revised: 01/27/2024] [Accepted: 01/29/2024] [Indexed: 02/25/2024] Open
Abstract
Hypoglycaemia-associated autonomic failure (HAAF) is characterised by an impairment in adrenal medullary and neurogenic symptom responses following episodes of recurrent hypoglycaemia. Here, we review the status quo of research related to the regulatory mechanisms of the adrenal medulla in its response to single and recurrent hypoglycaemia in both diabetic and non-diabetic subjects with particular focus given to catecholamine synthesis, enzymatic activity, and the impact of adrenal medullary peptides. Short-term post-transcriptional modifications, particularly phosphorylation at specific residues of tyrosine hydroxylase (TH), play a key role in the regulation of catecholamine synthesis. While the effects of recurrent hypoglycaemia on catecholamine synthetic enzymes remain inconsistent, long-term changes in TH protein expression suggest species-specific responses. Adrenomedullary peptides such as neuropeptide Y (NPY), galanin, and proenkephalin exhibit altered gene and protein expression in response to hypoglycaemia, suggesting a potential role in the modulation of catecholamine secretion. Of note is NPY, since its antagonism has been shown to prevent reductions in TH protein expression. This review highlights the need for further investigation into the molecular mechanisms involved in the adrenal medullary response to hypoglycaemia. Despite advancements in our understanding of HAAF in non-diabetic rodents, a reliable diabetic rodent model of HAAF remains a challenge.
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Affiliation(s)
- Manjula Senthilkumaran
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia
| | - Coen Koch
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia
| | - Mauritz Frederick Herselman
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia
| | - Larisa Bobrovskaya
- Health and Biomedical Innovation, Clinical and Health Sciences, University of South Australia, Adelaide, SA 5000, Australia
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13
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Hashmi HZ, Khowaja A, Moheet A. Experimental pharmacological approaches to reverse impaired awareness of hypoglycemia-a review. Front Pharmacol 2024; 15:1349004. [PMID: 38323079 PMCID: PMC10844401 DOI: 10.3389/fphar.2024.1349004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2023] [Accepted: 01/04/2024] [Indexed: 02/08/2024] Open
Abstract
The colossal global burden of diabetes management is compounded by the serious complication of hypoglycemia. Protective physiologic hormonal and neurogenic counterregulatory responses to hypoglycemia are essential to preserve glucose homeostasis and avert serious morbidity. With recurrent exposure to hypoglycemic episodes over time, these counterregulatory responses to hypoglycemia can diminish, resulting in an impaired awareness of hypoglycemia (IAH). IAH is characterized by sudden neuroglycopenia rather than preceding cautionary autonomic symptoms. IAH increases the risk of subsequent sudden and severe hypoglycemic episodes in patients with diabetes. The postulated causative mechanisms behind IAH are complex and varied. It is therefore challenging to identify a single effective therapeutic strategy. In this review, we closely examine the efficacy and feasibility of a myriad of pharmaceutical interventions in preventing and treating IAH as described in clinical and preclinical studies. Pharmaceutical agents outlined include N-acetyl cysteine, GABA A receptor blockers, opioid receptor antagonists, AMP activated protein kinase agonists, potassium channel openers, dehydroepiandrosterone, metoclopramide, antiadrenergic agents, antidiabetic agents and glucagon.
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Affiliation(s)
- Hiba Z. Hashmi
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
| | - Ameer Khowaja
- Northeast Endocrinology Associates, San Antonio, TX, United States
| | - Amir Moheet
- Division of Diabetes, Endocrinology and Metabolism, Department of Medicine, University of Minnesota, Minneapolis, MN, United States
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14
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Yoshida T, Fujitani M, Farmer S, Harada A, Shi Z, Lee JJ, Tinajero A, Singha AK, Fujikawa T. VMHdm/c SF-1 neuronal circuits regulate skeletal muscle PGC1-α via the sympathoadrenal drive. Mol Metab 2023; 77:101792. [PMID: 37633515 PMCID: PMC10491730 DOI: 10.1016/j.molmet.2023.101792] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2023] [Accepted: 08/14/2023] [Indexed: 08/28/2023] Open
Abstract
OBJECTIVE To adapt to metabolically challenging environments, the central nervous system (CNS) orchestrates metabolism of peripheral organs including skeletal muscle. The organ-communication between the CNS and skeletal muscle has been investigated, yet our understanding of the neuronal pathway from the CNS to skeletal muscle is still limited. Neurons in the dorsomedial and central parts of the ventromedial hypothalamic nucleus (VMHdm/c) expressing steroidogenic factor-1 (VMHdm/cSF-1 neurons) are key for metabolic adaptations to exercise, including increased basal metabolic rate and skeletal muscle mass in mice. However, the mechanisms by which VMHdm/cSF-1 neurons regulate skeletal muscle function remain unclear. Here, we show that VMHdm/cSF-1 neurons increase the sympathoadrenal activity and regulate skeletal muscle peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC-1α) in mice via multiple downstream nodes. METHODS Optogenetics was used to specifically manipulate VMHdm/cSF-1 neurons combined with genetically-engineered mice and surgical manipulation of the sympathoadrenal activity. RESULTS Optogenetic activation of VMHdm/cSF-1 neurons dramatically elevates mRNA levels of skeletal muscle Pgc-1α, which regulates a spectrum of skeletal muscle function including protein synthesis and metabolism. Mechanistically, the sympathoadrenal drive coupled with β2 adrenergic receptor (β2AdR) is essential for VMHdm/cSF-1 neurons-mediated increases in skeletal muscle PGC1-α. Specifically, both adrenalectomy and β2AdR knockout block augmented skeletal muscle PGC1-α by VMHdm/cSF-1 neuronal activation. Optogenetic functional mapping reveals that downstream nodes of VMHdm/cSF-1 neurons are functionally redundant to increase circulating epinephrine and skeletal muscle PGC1-α. CONCLUSIONS Collectively, we propose that VMHdm/cSF-1 neurons-skeletal muscle pathway, VMHdm/cSF-1 neurons→multiple downstream nodes→the adrenal gland→skeletal muscle β2AdR, underlies augmented skeletal muscle function for metabolic adaptations.
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Affiliation(s)
- Takuya Yoshida
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, USA; Department of Clinical Nutrition School of Food and Nutritional Sciences, University of Shizuoka, Shizuoka, Japan
| | - Mina Fujitani
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, USA; Laboratory of Nutrition Science, Department of Bioscience, Graduate School of Agriculture, Ehime University, Matsuyama, Japan
| | - Scotlynn Farmer
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, USA
| | - Ami Harada
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, USA; Nara Medical University, Nara, Japan
| | - Zhen Shi
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, USA; Department of Plastic Surgery, Hospital Zhejiang University School of Medicine, Zhejiang, China
| | - Jenny J Lee
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, USA
| | - Arely Tinajero
- Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, USA
| | - Ashish K Singha
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, USA
| | - Teppei Fujikawa
- Department of Cellular and Integrative Physiology, Long School of Medicine, University of Texas Health San Antonio, San Antonio, USA; Center for Hypothalamic Research, Department of Internal Medicine, UT Southwestern Medical Center, Dallas, USA.
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15
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Zhang J, Zheng Y, Martens L, Pfeiffer AFH. The Regulation and Secretion of Glucagon in Response to Nutrient Composition: Unraveling Their Intricate Mechanisms. Nutrients 2023; 15:3913. [PMID: 37764697 PMCID: PMC10536047 DOI: 10.3390/nu15183913] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2023] [Revised: 08/31/2023] [Accepted: 09/06/2023] [Indexed: 09/29/2023] Open
Abstract
Glucagon was initially regarded as a hyperglycemic substance; however, recent research has revealed its broader role in metabolism, encompassing effects on glucose, amino acids (AAs), and lipid metabolism. Notably, the interplay of glucagon with nutrient intake, particularly of AAs, and non-nutrient components is central to its secretion. Fasting and postprandial hyperglucagonemia have long been linked to the development and progression of type 2 diabetes (T2DM). However, recent studies have brought to light the positive impact of glucagon agonists on lipid metabolism and energy homeostasis. This review explores the multifaceted actions of glucagon, focusing on its regulation, signaling pathways, and effects on glucose, AAs, and lipid metabolism. The interplay between glucagon and other hormones, including insulin and incretins, is examined to provide a mechanistic understanding of its functions. Notably, the liver-α-cell axis, which involves glucagon and amino acids, emerges as a critical aspect of metabolic regulation. The dysregulation of glucagon secretion and its impact on conditions such as T2DM are discussed. The review highlights the potential therapeutic applications of targeting the glucagon pathway in the treatment of metabolic disorders.
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Affiliation(s)
- Jiudan Zhang
- The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou 310053, China;
- Department of Endocrinology, Diabetes and Nutrition, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (L.M.); (A.F.H.P.)
| | - Yang Zheng
- The First Affiliated Hospital of Zhejiang Chinese Medical University, Hangzhou 310053, China;
| | - Lisa Martens
- Department of Endocrinology, Diabetes and Nutrition, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (L.M.); (A.F.H.P.)
- Nutritional Science, University of Potsdam, 14469 Potsdam, Germany
| | - Andreas F. H. Pfeiffer
- Department of Endocrinology, Diabetes and Nutrition, Charité-Universitätsmedizin Berlin, Corporate Member of Freie Universität Berlin, Humboldt-Universität zu Berlin, and Berlin Institute of Health, 10117 Berlin, Germany; (L.M.); (A.F.H.P.)
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16
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Gaspari S, Labouèbe G, Picard A, Berney X, Rodriguez Sanchez‐Archidona A, Thorens B. Tmem117 in AVP neurons regulates the counterregulatory response to hypoglycemia. EMBO Rep 2023; 24:e57344. [PMID: 37314252 PMCID: PMC10398655 DOI: 10.15252/embr.202357344] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2023] [Revised: 05/21/2023] [Accepted: 05/31/2023] [Indexed: 06/15/2023] Open
Abstract
The counterregulatory response to hypoglycemia (CRR), which ensures a sufficient glucose supply to the brain, is an essential survival function. It is orchestrated by incompletely characterized glucose-sensing neurons, which trigger a coordinated autonomous and hormonal response that restores normoglycemia. Here, we investigate the role of hypothalamic Tmem117, identified in a genetic screen as a regulator of CRR. We show that Tmem117 is expressed in vasopressin magnocellular neurons of the hypothalamus. Tmem117 inactivation in these neurons increases hypoglycemia-induced vasopressin secretion leading to higher glucagon secretion in male mice, and this effect is estrus cycle phase dependent in female mice. Ex vivo electrophysiological analysis, in situ hybridization, and in vivo calcium imaging reveal that Tmem117 inactivation does not affect the glucose-sensing properties of vasopressin neurons but increases ER stress, ROS production, and intracellular calcium levels accompanied by increased vasopressin production and secretion. Thus, Tmem117 in vasopressin neurons is a physiological regulator of glucagon secretion, which highlights the role of these neurons in the coordinated response to hypoglycemia.
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Affiliation(s)
- Sevasti Gaspari
- Center for Integrative GenomicsUniversity of LausanneLausanneSwitzerland
| | - Gwenaël Labouèbe
- Center for Integrative GenomicsUniversity of LausanneLausanneSwitzerland
| | - Alexandre Picard
- Center for Integrative GenomicsUniversity of LausanneLausanneSwitzerland
| | - Xavier Berney
- Center for Integrative GenomicsUniversity of LausanneLausanneSwitzerland
| | | | - Bernard Thorens
- Center for Integrative GenomicsUniversity of LausanneLausanneSwitzerland
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17
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Pan S, Worker CJ, Feng Earley Y. The hypothalamus as a key regulator of glucose homeostasis: emerging roles of the brain renin-angiotensin system. Am J Physiol Cell Physiol 2023; 325:C141-C154. [PMID: 37273237 PMCID: PMC10312332 DOI: 10.1152/ajpcell.00533.2022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2022] [Revised: 05/26/2023] [Accepted: 05/26/2023] [Indexed: 06/06/2023]
Abstract
The regulation of plasma glucose levels is a complex and multifactorial process involving a network of receptors and signaling pathways across numerous organs that act in concert to ensure homeostasis. However, much about the mechanisms and pathways by which the brain regulates glycemic homeostasis remains poorly understood. Understanding the precise mechanisms and circuits employed by the central nervous system to control glucose is critical to resolving the diabetes epidemic. The hypothalamus, a key integrative center within the central nervous system, has recently emerged as a critical site in the regulation of glucose homeostasis. Here, we review the current understanding of the role of the hypothalamus in regulating glucose homeostasis, with an emphasis on the paraventricular nucleus, the arcuate nucleus, the ventromedial hypothalamus, and lateral hypothalamus. In particular, we highlight the emerging role of the brain renin-angiotensin system in the hypothalamus in regulating energy expenditure and metabolic rate, as well as its potential importance in the regulation of glucose homeostasis.
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Affiliation(s)
- Shiyue Pan
- Department of Pharmacology, School of Medicine, University of Nevada, Reno, Reno, Nevada, United States
- Department of Physiology & Cell Biology, School of Medicine, University of Nevada, Reno, Reno, Nevada, United States
- Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno, Reno, Nevada, United States
| | - Caleb J Worker
- Department of Pharmacology, School of Medicine, University of Nevada, Reno, Reno, Nevada, United States
- Department of Physiology & Cell Biology, School of Medicine, University of Nevada, Reno, Reno, Nevada, United States
- Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno, Reno, Nevada, United States
| | - Yumei Feng Earley
- Department of Pharmacology, School of Medicine, University of Nevada, Reno, Reno, Nevada, United States
- Department of Physiology & Cell Biology, School of Medicine, University of Nevada, Reno, Reno, Nevada, United States
- Center for Molecular and Cellular Signaling in the Cardiovascular System, University of Nevada, Reno, Reno, Nevada, United States
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18
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Lewis ST, Greenway F, Tucker TR, Alexander M, Jackson LK, Hepford SA, Loveridge B, Lakey JRT. A Receptor Story: Insulin Resistance Pathophysiology and Physiologic Insulin Resensitization's Role as a Treatment Modality. Int J Mol Sci 2023; 24:10927. [PMID: 37446104 DOI: 10.3390/ijms241310927] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2023] [Revised: 06/23/2023] [Accepted: 06/25/2023] [Indexed: 07/15/2023] Open
Abstract
Physiologic insulin secretion consists of an oscillating pattern of secretion followed by distinct trough periods that stimulate ligand and receptor activation. Apart from the large postprandial bolus release of insulin, β cells also secrete small amounts of insulin every 4-8 min independent of a meal. Insulin resistance is associated with a disruption in the normal cyclical pattern of insulin secretion. In the case of type-2 diabetes, β-cell mass is reduced due to apoptosis and β cells secrete insulin asynchronously. When ligand/receptors are constantly exposed to insulin, a negative feedback loop down regulates insulin receptor availability to insulin, creating a relative hyperinsulinemia. The relative excess of insulin leads to insulin resistance (IR) due to decreased receptor availability. Over time, progressive insulin resistance compromises carbohydrate metabolism, and may progress to type-2 diabetes (T2D). In this review, we discuss insulin resistance pathophysiology and the use of dynamic exogenous insulin administration in a manner consistent with more normal insulin secretion periodicity to reverse insulin resistance. Administration of insulin in such a physiologic manner appears to improve insulin sensitivity, lower HgbA1c, and, in some instances, has been associated with the reversal of end-organ damage that leads to complications of diabetes. This review outlines the rationale for how the physiologic secretion of insulin orchestrates glucose metabolism, and how mimicking this secretion profile may serve to improve glycemic control, reduce cellular inflammation, and potentially improve outcomes in patients with diabetes.
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Affiliation(s)
| | - Frank Greenway
- Clinical Trials Unit, Pennington Biomedical Research Center, Louisiana State University, Baton Rouge, LA 77808, USA
| | - Tori R Tucker
- Department of Developmental and Cell Biology, University of California Irvine, Irvine, CA 92617, USA
| | - Michael Alexander
- Department of Surgery, University of California Irvine, Orange, CA 92686, USA
| | - Levonika K Jackson
- Well Cell Global, Medical and Scientific Advisory Board, Houston, TX 77079, USA
| | - Scott A Hepford
- Well Cell Global, Medical and Scientific Advisory Board, Houston, TX 77079, USA
| | - Brian Loveridge
- Well Cell Global, Medical and Scientific Advisory Board, Houston, TX 77079, USA
| | - Jonathan R T Lakey
- Department of Surgery, University of California Irvine, Orange, CA 92686, USA
- Department of Biomedical Engineering, University of California Irvine, Irvine, CA 92868, USA
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19
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She R, Al-Sari NH, Mattila IM, Sejling AS, Pedersen J, Legido-Quigley C, Pedersen-Bjergaard U. Decreased branched-chain amino acids and elevated fatty acids during antecedent hypoglycemia in type 1 diabetes. BMJ Open Diabetes Res Care 2023; 11:e003327. [PMID: 37369531 PMCID: PMC10410980 DOI: 10.1136/bmjdrc-2023-003327] [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: 01/19/2023] [Accepted: 06/08/2023] [Indexed: 06/29/2023] Open
Abstract
INTRODUCTION Hypoglycemia is a major limiting factor in achieving recommended glycemic targets for people with type 1 diabetes. Exposure to recurrent hypoglycemia results in blunted hormonal counter-regulatory and symptomatic responses to hypoglycemia. Limited data on metabolic adaptation to recurrent hypoglycemia are available. This study examined the acute metabolic responses to hypoglycemia and the effect of antecedent hypoglycemia on these responses in type 1 diabetes. RESEARCH DESIGN AND METHODS Twenty-one outpatients with type 1 diabetes with normal or impaired awareness of hypoglycemia participated in a study assessing the response to hypoglycemia on 2 consecutive days by a hyperinsulinemic glucose clamp. Participants underwent a period of normoglycemia and a period of hypoglycemia during the hyperinsulinemic glucose clamp. Plasma samples were taken during normoglycemia and at the beginning and the end of the hypoglycemic period. Metabolomic analysis of the plasma samples was conducted using comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry. RESULTS In total, 68 metabolites were studied. On day 1, concentrations of the branched-chain amino acids, leucine (p=3.8×10-3) and isoleucine (p=2.2×10-3), decreased during hypoglycemia. On day 2, during hypoglycemia, five amino acids (including leucine and isoleucine) significantly decreased, and two fatty acids (tetradecanoic and oleic acids) significantly increased (p<0.05). Although more metabolites responded to hypoglycemia on day 2, the responses of the single metabolites were not statistically significant between the 2 days. CONCLUSIONS In individuals with type 1 diabetes, one episode of hypoglycemia decreases leucine and isoleucine concentrations. Antecedent hypoglycemia results in the decrement of five amino acids and increases the concentrations of two fatty acids, suggesting an alteration between the two hypoglycemic episodes, which could indicate a possible adaptation. However, more studies are needed to gain a comprehensive understanding of the consequences of these alterations. TRIAL REGISTRATION NUMBER NCT01337362.
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Affiliation(s)
- Rui She
- Department of Endocrinology and Nephrology, Nordsjællands Hospital, Hillerød, Capital Region of Denmark, Denmark
- Department of Clinical Medicine, University of Copenhagen Faculty of Health and Medical Sciences, Kobenhavn, Capital Region of Denmark, Denmark
| | - Naba Hassan Al-Sari
- Clinical Research, Steno Diabetes Center Copenhagen, Herlev, Capital Region of Denmark, Denmark
| | - Ismo Matias Mattila
- Clinical Research, Steno Diabetes Center Copenhagen, Herlev, Capital Region of Denmark, Denmark
| | - Anne-Sophie Sejling
- Boston Global Development, Novo Nordisk, Søborg, Capital Region of Denmark, Denmark
| | - Jens Pedersen
- Department of Internal Medicine, Herlev Hospital, Herlev, Capital Region of Denmark, Denmark
| | - Cristina Legido-Quigley
- Clinical Research, Steno Diabetes Center Copenhagen, Herlev, Capital Region of Denmark, Denmark
- Institute of Pharmaceutical Science, King's College London, London, UK
| | - Ulrik Pedersen-Bjergaard
- Department of Endocrinology and Nephrology, Nordsjællands Hospital, Hillerød, Capital Region of Denmark, Denmark
- Department of Clinical Medicine, University of Copenhagen Faculty of Health and Medical Sciences, Kobenhavn, Capital Region of Denmark, Denmark
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20
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Fessel J. Cure of Alzheimer's Dementia in Many Patients by Using Intranasal Insulin to Augment an Inadequate Counter-Reaction, Edaravone to Scavenge ROS, and 1 or 2 Other Drugs to Address Affected Brain Cells. J Clin Med 2023; 12:jcm12093151. [PMID: 37176592 PMCID: PMC10178959 DOI: 10.3390/jcm12093151] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2023] [Revised: 04/20/2023] [Accepted: 04/24/2023] [Indexed: 05/15/2023] Open
Abstract
The goal of treatment for Alzheimer's dementia (AD) is the restoration of normal cognition. No drug regimen has ever achieved this. This article suggests that curing AD may be achieved by combination therapy as follows. First, with intranasal insulin to augment the body's natural counter-reaction to the changes in brain cell-types that produced the dementia. Second, with edaravone to decrease free radicals, which are increased and causal in AD. Third, as described elsewhere, with one or two drugs from among pioglitazone, fluoxetine, and lithium, which address the brain cell-types whose changed functions cause the dementia. Insulin restores cerebral glucose, which is the main nutrient for brain neurons whose depletion is responsible for the dementia; and edaravone decreases ROS, which are intrinsic causes of neuropathology in AD. This combination of drugs is a potential cure for many patients with AD, and should be tested in a clinical trial.
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Affiliation(s)
- Jeffrey Fessel
- Department of Medicine, University of California San Francisco, 2069 Filbert Street, San Francisco, CA 94123, USA
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21
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Yonamine CY, Passarelli M, Suemoto CK, Pasqualucci CA, Jacob-Filho W, Alves VAF, Marie SKN, Correa-Giannella ML, Britto LR, Machado UF. Postmortem Brains from Subjects with Diabetes Mellitus Display Reduced GLUT4 Expression and Soma Area in Hippocampal Neurons: Potential Involvement of Inflammation. Cells 2023; 12:cells12091250. [PMID: 37174649 PMCID: PMC10177173 DOI: 10.3390/cells12091250] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2023] [Revised: 04/13/2023] [Accepted: 04/23/2023] [Indexed: 05/15/2023] Open
Abstract
Diabetes mellitus (DM) is an important risk factor for dementia, which is a common neurodegenerative disorder. DM is known to activate inflammation, oxidative stress, and advanced glycation end products (AGEs) generation, all capable of inducing neuronal dysfunctions, thus participating in the neurodegeneration progress. In that process, disturbed neuronal glucose supply plays a key role, which in hippocampal neurons is controlled by the insulin-sensitive glucose transporter type 4 (GLUT4). We investigated the expression of GLUT4, nuclear factor NF-kappa B subunit p65 [NFKB (p65)], carboxymethyllysine and synapsin1 (immunohistochemistry), and soma area in human postmortem hippocampal samples from control, obese, and obese+DM subjects (41 subjects). Moreover, in human SH-SY5Y neurons, tumor necrosis factor (TNF) and glycated albumin (GA) effects were investigated in GLUT4, synapsin-1 (SYN1), tyrosine hydroxylase (TH), synaptophysin (SYP) proteins, and respective genes; NFKB binding activity in the SLC2A4 promoter; effects of increased histone acetylation grade by histone deacetylase 3 (HDAC3) inhibition. Hippocampal neurons (CA4 area) of obese+DM subjects displayed reduced GLUT4 expression and neuronal soma area, associated with increased expression of NFKB (p65). Challenges with TNF and GA decreased the SLC2A4/GLUT4 expression in SH-SY5Y neurons. TNF decreased SYN1, TH, and SYP mRNAs and respective proteins, and increased NFKB binding activity in the SLC2A4 promoter. Inhibition of HDAC3 increased the SLC2A4 expression and the total neuronal content of CRE-binding proteins (CREB/ICER), and also counterbalanced the repressor effect of TNF upon these parameters. This study revealed reduced postmortem human hippocampal GLUT4 content and neuronal soma area accompanied by increased proinflammatory activity in the brains of DM subjects. In isolated human neurons, inflammatory activation by TNF reduced not only the SLC2A4/GLUT4 expression but also the expression of some genes related to neuronal function (SYN1, TH, SYP). These effects may be related to epigenetic regulations (H3Kac and H4Kac status) since they can be counterbalanced by inhibiting HDAC3. These results uncover the improvement in GLUT4 expression and/or the inhibition of HDAC3 as promising therapeutic targets to fight DM-related neurodegeneration.
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Affiliation(s)
- Caio Yogi Yonamine
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, DK-2200 Copenhagen, Denmark
| | - Marisa Passarelli
- Laboratório de Lipides (LIM-10) do HCFMUSP, Faculdade de Medicina, Universidade de São Paulo, São Paulo 01246-000, Brazil
- Programa de Pos-Graduação em Medicina, Universidade Nove de Julho (UNINOVE), São Paulo 01525-000, Brazil
| | - Claudia Kimie Suemoto
- Divisao de Geriatria, Faculdade de Medicina, Universidade de Sao Paulo, São Paulo 01246-000, Brazil
| | | | - Wilson Jacob-Filho
- Divisao de Geriatria, Faculdade de Medicina, Universidade de Sao Paulo, São Paulo 01246-000, Brazil
| | - Venâncio Avancini Ferreira Alves
- Laboratório de Investigação Médica em Patologia Hepática, (LIM14) do Hospital das Clínicas (HCFMUSP), Faculdade de Medicina, Universidade de São Paulo, São Paulo 01246-000, Brazil
| | | | - Maria Lucia Correa-Giannella
- Laboratorio de Carboidratos e Radioimunoensaio (LIM-18) do Hospital das Clinicas HCFMUSP, Faculdade de Medicina, Universidade de Sao Paulo, São Paulo 01246-000, Brazil
| | - Luiz Roberto Britto
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
| | - Ubiratan Fabres Machado
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo 05508-000, Brazil
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22
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Palani G, Stortz E, Moheet A. Clinical Presentation and Diagnostic Approach to Hypoglycemia in Adults Without Diabetes Mellitus. Endocr Pract 2023; 29:286-294. [PMID: 36464132 DOI: 10.1016/j.eprac.2022.11.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/06/2022] [Revised: 10/24/2022] [Accepted: 11/28/2022] [Indexed: 12/03/2022]
Abstract
OBJECTIVE To review the clinical presentation, causes, and diagnostic approach to spontaneous hypoglycemia in adults without diabetes mellitus. METHODS A literature review was performed using the PubMed and Google Scholar databases. RESULTS Hypoglycemia is uncommon in people who are not on glucose-lowering medications. Under normal physiologic conditions, multiple neural and hormonal counterregulatory mechanisms prevent the development of abnormally low levels of plasma glucose. If spontaneous hypoglycemia is suspected, the Whipple triad should be used to confirm hypoglycemia before pursuing further diagnostic workup. The Whipple criteria include the following: (1) low levels of plasma glucose, (2) signs or symptoms that would be expected with low levels of plasma glucose, and (3) improvement in those signs or symptoms when the level of plasma glucose increases. Spontaneous hypoglycemia can be caused by conditions that cause endogenous hyperinsulinism, including insulinoma, postbariatric hypoglycemia, and noninsulinoma pancreatogenous hypoglycemia. Spontaneous hypoglycemia can also be seen with critical illness, hepatic or renal dysfunction, hormonal deficiency, non-diabetes-related medications, and non-islet cell tumors. The initial diagnostic approach should begin by obtaining a detailed history of the nature and timing of the patient's symptoms, medications, underlying comorbid conditions, and any acute illness. A laboratory evaluation should be conducted at the time of the spontaneous symptomatic episode. Supervised tests such as a 72-hour fast or mixed-meal test may be needed to recreate the situation under which the patient is likely to experience symptoms. CONCLUSION We provide an overview of the physiology of counterregulatory response to hypoglycemia, its causes, and diagnostic approaches to spontaneous hypoglycemia in adults.
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Affiliation(s)
- Gurunanthan Palani
- Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Ethan Stortz
- Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota, Minneapolis, Minnesota
| | - Amir Moheet
- Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota, Minneapolis, Minnesota.
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23
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Eriksson JW, Emad RA, Lundqvist MH, Abrahamsson N, Kjellsson MC. Altered glucose-dependent secretion of glucagon and ACTH is associated with insulin resistance, assessed by population analysis. Endocr Connect 2023; 12:e220506. [PMID: 36752854 PMCID: PMC10083665 DOI: 10.1530/ec-22-0506] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Accepted: 02/08/2023] [Indexed: 02/09/2023]
Abstract
This study aimed to characterize how the dysregulation of counter-regulatory hormones can contribute to insulin resistance and potentially to diabetes. Therefore, we investigated the association between insulin sensitivity and the glucose- and insulin-dependent secretion of glucagon, adrenocorticotropic hormone (ACTH), and cortisol in non-diabetic individuals using a population model analysis. Data, from hyperinsulinemic-hypoglycemic clamps, were pooled for analysis, including 52 individuals with a wide range of insulin resistance (reflected by glucose infusion rate 20-60 min; GIR20-60min). Glucagon secretion was suppressed by glucose and, to a lesser extent, insulin. The GIR20-60min and BMI were identified as predictors of the insulin effect on glucagon. At normoglycemia (5 mmol/L), a 90% suppression of glucagon was achieved at insulin concentrations of 16.3 and 43.4 µU/mL in individuals belonging to the highest and lowest quantiles of insulin sensitivity, respectively. Insulin resistance of glucagon secretion explained the elevated fasting glucagon for individuals with a low GIR20-60min. ACTH secretion was suppressed by glucose and not affected by insulin. The GIR20-60min was superior to other measures as a predictor of glucose-dependent ACTH secretion, with 90% suppression of ACTH secretion by glucose at 3.1 and 3.5 mmol/L for insulin-sensitive and insulin-resistant individuals, respectively. This difference may appear small but shifts the suppression range into normoglycemia for individuals with insulin resistance, thus, leading to earlier and greater ACTH/cortisol response when the glucose falls. Based on modeling of pooled glucose-clamp data, insulin resistance was associated with generally elevated glucagon and a potentiated cortisol-axis response to hypoglycemia, and over time both hormonal pathways may therefore contribute to dysglycemia and possibly type 2 diabetes.
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Affiliation(s)
- Jan W Eriksson
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Reem A Emad
- Department of Pharmacy, Uppsala University, Uppsala, Sweden
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24
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Epigenetic regulation of Neuregulin 1 promotes breast cancer progression associated to hyperglycemia. Nat Commun 2023; 14:439. [PMID: 36707514 PMCID: PMC9883495 DOI: 10.1038/s41467-023-36179-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2022] [Accepted: 01/18/2023] [Indexed: 01/28/2023] Open
Abstract
Hyperglycemia is a risk factor for breast cancer-related morbidity and mortality. Hyperglycemia induces Neuregulin 1 (Nrg1) overexpression in breast cancer, which subsequently promotes tumor progression. However, molecular mechanisms underlying hyperglycemia-induced Nrg1 overexpression remain poorly understood. Here, we show that hyperglycemia causes active histone modifications at the Nrg1 enhancer, forming enhanceosome complexes where recombination signal binding protein for immunoglobulin kappa J region (RBPJ), E1A binding protein p300 (P300), and SET domain containing 1 A (SETD1A) are recruited to upregulate Nrg1 expression. Deletions in RBPJ-binding sites causes hyperglycemia-controlled Nrg1 levels to be downregulated, resulting in decreased tumor growth in vitro and in vivo. Mice with modest-temporary hyperglycemia, induced by low-dose short-exposure streptozotocin, display accelerated tumor growth and lapatinib resistance, whereas combining lapatinib with N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S42 phenylglycine t-butyl ester (DAPT) ameliorates tumor growth under these modest hyperglycemic conditions by inhibiting NOTCH and EGFR superfamilies. NOTCH activity is correlated with NRG1 levels, and high NRG1 levels predicts poor outcomes, particularly in HER2-positive breast cancer patients. Our findings highlight the hyperglycemia-linked epigenetic modulation of NRG1 as a potential therapeutic strategy for treating breast cancer patients with diabetes.
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25
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McCrimmon RJ. Remembrance of things past: The consequences of recurrent hypoglycaemia in diabetes. Diabet Med 2022; 39:e14973. [PMID: 36251572 PMCID: PMC10015985 DOI: 10.1111/dme.14973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/08/2022] [Revised: 10/03/2022] [Accepted: 10/13/2022] [Indexed: 01/18/2023]
Abstract
AIMS People with type 1 and type 2 diabetes still frequently experience hypoglycaemia, which can be severe, leading to loss of consciousness. This review will examine the cellular consequences of recurrent hypoglycaemia. METHODS This review, based on the Dorothy Hodgkin Lecture given at the Diabetes UK 2022 annual symposium by the author, will discuss our current understanding of the mechanisms by which hypoglycaemia is detected and the consequences of recurrent exposure to hypoglycaemia. RESULTS Glucose-responsive cells found in the periphery as well as multiple areas of the brain are organised in a classical sensori-motor integrative network encompassing peripheral, hindbrain and hypothalamic components. The mechanism used by glucose-responsive neurons to detect hypoglycaemia parallel those of the classical glucose sensor the pancreatic ß-cell, namely in their use of glucokinase, KATP channels and AMP-activated protein kinase. Recurrent exposure to hypoglycaemia results in a series of cellular adaptations that may be designed to increase the resilience of cells to future hypoglycaemia. This review also highlights how hypoglycaemia, as an oxidative stressor, may also exacerbate chronic hyperglycaemia-induced increases in oxidative stress and inflammation, leading to damage to vulnerable brain regions. CONCLUSIONS Impaired awareness of hypoglycaemia follows the adaptation of central glucose-responsive neurons to repeated hypoglycaemia and may represent a form of memory called habituation. In diabetes, recurrent hypoglycaemia may have tissue consequences as a result of a profound disruption in the cellular response to a hypoglycaemic challenge that increases vulnerability to oxidative damage.
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Affiliation(s)
- Rory J. McCrimmon
- Systems Medicine, School of MedicineUniversity of Dundee, Ninewells Hospital and Medical SchoolDundeeUK
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26
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Sanchez-Rangel E, Deajon-Jackson J, Hwang JJ. Pathophysiology and management of hypoglycemia in diabetes. Ann N Y Acad Sci 2022; 1518:25-46. [PMID: 36202764 DOI: 10.1111/nyas.14904] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
In the century since the discovery of insulin, diabetes has changed from an early death sentence to a manageable chronic disease. This change in longevity and duration of diabetes coupled with significant advances in therapeutic options for patients has fundamentally changed the landscape of diabetes management, particularly in patients with type 1 diabetes mellitus. However, hypoglycemia remains a major barrier to achieving optimal glycemic control. Current understanding of the mechanisms of hypoglycemia has expanded to include not only counter-regulatory hormonal responses but also direct changes in brain glucose, fuel sensing, and utilization, as well as changes in neural networks that modulate behavior, mood, and cognition. Different strategies to prevent and treat hypoglycemia have been developed, including educational strategies, new insulin formulations, delivery devices, novel technologies, and pharmacologic targets. This review article will discuss current literature contributing to our understanding of the myriad of factors that lead to the development of clinically meaningful hypoglycemia and review established and novel therapies for the prevention and treatment of hypoglycemia.
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Affiliation(s)
- Elizabeth Sanchez-Rangel
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Jelani Deajon-Jackson
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Janice Jin Hwang
- Department of Internal Medicine, Section of Endocrinology, Yale University School of Medicine, New Haven, Connecticut, USA.,Division of Endocrinology, Department of Internal Medicine, University of North Carolina - Chapel Hill, Chapel Hill, North Carolina, USA
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27
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Herrera Moro Chao D, Kirchner MK, Pham C, Foppen E, Denis RGP, Castel J, Morel C, Montalban E, Hassouna R, Bui LC, Renault J, Mouffle C, García-Cáceres C, Tschöp MH, Li D, Martin C, Stern JE, Luquet SH. Hypothalamic astrocytes control systemic glucose metabolism and energy balance. Cell Metab 2022; 34:1532-1547.e6. [PMID: 36198294 PMCID: PMC9615252 DOI: 10.1016/j.cmet.2022.09.002] [Citation(s) in RCA: 26] [Impact Index Per Article: 13.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Revised: 06/23/2022] [Accepted: 09/02/2022] [Indexed: 01/29/2023]
Abstract
The hypothalamus is key in the control of energy balance. However, strategies targeting hypothalamic neurons have failed to provide viable options to treat most metabolic diseases. Conversely, the role of astrocytes in systemic metabolic control has remained largely unexplored. Here, we show that obesity promotes anatomically restricted remodeling of hypothalamic astrocyte activity. In the paraventricular nucleus (PVN) of the hypothalamus, chemogenetic manipulation of astrocytes results in bidirectional control of neighboring neuron activity, autonomic outflow, glucose metabolism, and energy balance. This process recruits a mechanism involving the astrocytic control of ambient glutamate levels, which becomes defective in obesity. Positive or negative chemogenetic manipulation of PVN astrocyte Ca2+ signals, respectively, worsens or improves metabolic status of diet-induced obese mice. Collectively, these findings highlight a yet unappreciated role for astrocytes in the direct control of systemic metabolism and suggest potential targets for anti-obesity strategy.
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Affiliation(s)
| | - Matthew K Kirchner
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA; Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, GA 30302, USA
| | - Cuong Pham
- Institute of Biology Paris Seine, Neuroscience Paris Seine, CNRS UMR8246, INSERM U1130, Sorbonne Universite, Paris 75005, France
| | - Ewout Foppen
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Raphael G P Denis
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France; Institut Cochin, Université Paris Cité, INSERM U1016, CNRS UMR 8104, 75014 Paris, France
| | - Julien Castel
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Chloe Morel
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Enrica Montalban
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Rim Hassouna
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Linh-Chi Bui
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Justine Renault
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Christine Mouffle
- Institute of Biology Paris Seine, Neuroscience Paris Seine, CNRS UMR8246, INSERM U1130, Sorbonne Universite, Paris 75005, France
| | - Cristina García-Cáceres
- Helmholtz Diabetes Center (HDC) & German Center for Diabetes Research (DZD), Helmholtz Zentrum München, Neuherberg, 85764, Germany; Division of Metabolic Diseases, Technische Universität München, Munich, 80333, Germany; Medizinische Klinik and Poliklinik IV, Klinikum der Universität, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Matthias H Tschöp
- Helmholtz Diabetes Center (HDC) & German Center for Diabetes Research (DZD), Helmholtz Zentrum München, Neuherberg, 85764, Germany; Division of Metabolic Diseases, Technische Universität München, Munich, 80333, Germany
| | - Dongdong Li
- Institute of Biology Paris Seine, Neuroscience Paris Seine, CNRS UMR8246, INSERM U1130, Sorbonne Universite, Paris 75005, France
| | - Claire Martin
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France
| | - Javier E Stern
- Neuroscience Institute, Georgia State University, Atlanta, GA 30303, USA; Center for Neuroinflammation and Cardiometabolic Diseases, Georgia State University, Atlanta, GA 30302, USA
| | - Serge H Luquet
- Université Paris Cité, CNRS, Unité de Biologie Fonctionnelle et Adaptative, Paris, France.
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28
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Lipid biosynthesis enzyme Agpat5 in AgRP-neurons is required for insulin-induced hypoglycemia sensing and glucagon secretion. Nat Commun 2022; 13:5761. [PMID: 36180454 PMCID: PMC9525695 DOI: 10.1038/s41467-022-33484-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2022] [Accepted: 09/21/2022] [Indexed: 11/13/2022] Open
Abstract
The counterregulatory response to hypoglycemia that restores normal blood glucose levels is an essential physiological function. It is initiated, in large part, by incompletely characterized brain hypoglycemia sensing neurons that trigger the secretion of counterregulatory hormones, in particular glucagon, to stimulate hepatic glucose production. In a genetic screen of recombinant inbred BXD mice we previously identified Agpat5 as a candidate regulator of hypoglycemia-induced glucagon secretion. Here, using genetic mouse models, we demonstrate that Agpat5 expressed in agouti-related peptide neurons is required for their activation by hypoglycemia, for hypoglycemia-induced vagal nerve activity, and glucagon secretion. We find that inactivation of Agpat5 leads to increased fatty acid oxidation and ATP production and that suppressing Cpt1a-dependent fatty acid import into mitochondria restores hypoglycemia sensing. Collectively, our data show that AgRP neurons are involved in the control of glucagon secretion and that Agpat5, by partitioning fatty acyl-CoAs away from mitochondrial fatty acid oxidation and ATP generation, ensures that the fall in intracellular ATP, which triggers neuronal firing, faithfully reflects changes in glycemia. During hypoglycemia, glucagon secretion is part of the mechanism needed to restore normal blood glucose levels. Here, Strembitska et al. report that sensing of hypoglycemia by AgRP neurons requires Agpat5, an enzyme which prevents fatty acids from entering the mitochondria for ATP production, ensuring correct neuronal activation and glucagon secretion.
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29
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Lijing W, Sujie K, Linxi W, Lishan H, Liqin Q, Zhidong Z, Kejun W, Mengjun Z, Xiaoying L, Xiaohong L, Libin L. Altered Caffeine Metabolism Is Associated With Recurrent Hypoglycemia in Type 2 Diabetes Mellitus: A UPLC-MS-Based Untargeted Metabolomics Study. Front Endocrinol (Lausanne) 2022; 13:843556. [PMID: 35784552 PMCID: PMC9248032 DOI: 10.3389/fendo.2022.843556] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/26/2021] [Accepted: 05/02/2022] [Indexed: 11/18/2022] Open
Abstract
Background Recurrent hypoglycemia (RH) is well known to impair awareness of hypoglycemia and increase the risk of severe hypoglycemia; the underlying mechanism requires further understanding. We aimed to investigate the metabolic characteristic profile for RH in type 2 diabetes mellitus (T2DM) patients and explore the potential metabolic mechanism and prevention strategies. Methods We screened 553 community-based T2DM patients. T2DM with RH (DH group, n=40) and T2DM without hypoglycemia (DC group, n=40) were assigned in the case-control study, matched by propensity score matching. Non-targeted, global metabolite profiling was conducted using ultra-high performance liquid chromatography-mass spectrometry. Principal component analysis and supervised projections to latent structures-discriminant analysis were constructed to evaluate the potential biomarkers. Metabolites with a fold change of >2.0 or <0.5, a t-test q-value <0.05, and variable importance in projection value of >1 were identified as significantly differential metabolites. MetaboAnalyst was performed to analyze the related metabolic pathways. Results We identified 12 significantly distinct metabolites as potential biomarkers of RH, which were enriched in five pathways; the caffeine metabolic pathway was the most dominant related one. Caffeine and its main downstream metabolites (theophylline and paraxanthine, all q <0.05) were significantly lower during RH. The combination of these metabolites can serve as a reliable predictor biomarker for RH (area under the curve = 0.88). Regarding lipid metabolism, triglyceride was upregulated (P=0.003) and the O-Acylcarnitine was downregulated (q < 0.001). Besides, RH was accompanied by lower phenylalanine (q=0.003) and higher cortisone (q=0.005) levels. Conclusions RH in T2DM is accompanied by caffeine, lipolysis, phenylalanine, and cortisone metabolism abnormalities. Caffeine might be a reliable candidate biomarker and potential prevention strategy for RH, but further validation studies are needed. Clinical Trial Registry Chi CTR 1900026361, 2019-10-3.
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Affiliation(s)
- Wang Lijing
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Ke Sujie
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Wang Linxi
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Huang Lishan
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Qi Liqin
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Zhan Zhidong
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Wu Kejun
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Zhang Mengjun
- The School of Pharmacy, Fujian Medical University, Fuzhou, China
| | - Liu Xiaoying
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Liu Xiaohong
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, China
| | - Liu Libin
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, China
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30
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Koracevic G, Micic S, Stojanovic M, Radovanovic RV, Pavlovic MP, Kostic T, Djordjevic D, Antonijevic N, Koracevic M, Atanaskovic V, Dakic S. Beta Blockers can mask not only Hypoglycemia, but also Hypotension. Curr Pharm Des 2022; 28:1660-1668. [DOI: 10.2174/1381612828666220421135523] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 02/01/2022] [Indexed: 11/22/2022]
Abstract
Background:
Beta-adrenergic (β-AR) receptor blockers (BBs) are an essential class of drugs as they have numerous indications. On the other hand, they have numerous unwanted effects which decrease the compliance, adherence, and persistence of this very useful group of drugs.
Objective:
The paper aims to analyze the possibility that an unnoticed side effect may contribute to a less favorable pharmacologic profile of BBs, e.g., a diminished reaction to a sudden fall in BP.
Methods:
We searched two medical databases for abstracts and citations (Medline and SCOPUS). Moreover, we searched the internet for drug prescription leaflets (of the individual BBs).
Results:
Whichever cause of stress is considered, the somatic manifestations of stress will be (partially) masked if a patient takes BB. Stress–induced hypercatecholaminemia acts on β-AR of cardiomyocytes; it increases heart rate and contractility, effects suppressed by BBs. The answers of the organism to hypoglycemia and hypotension share the main mechanisms such as sympathetic nervous system activation and hypercatecholaminemia. Thus, there is a striking analogy: BBs can cover up symptoms of both hypoglycemia (which is widely known) and of hypotension (which is not recognized). It is widely known that BBs can cause hypotension. However, they can also complicate recovery by spoiling the defense mechanisms in hypotension as they interfere with the crucial compensatory reflex to increase blood pressure in hypotension.
Conclusion:
Beta blockers can cause hypotension, mask it, and make recovery more difficult. This is clinically important and deserves to be more investigated and probably to be stated as a warning.
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Affiliation(s)
- Goran Koracevic
- Department for Cardiovascular Diseases, University Clinical Centre Nis, Nis, Serbia
| | | | | | | | - Milan Pavlovic Pavlovic
- Department for Cardiovascular Diseases, University Clinical Centre Nis, Nis, Serbia
- Faculty of Medicine, University of Nis, Nis, Serbia
| | - Tomislav Kostic
- Department for Cardiovascular Diseases, University Clinical Centre Nis, Nis, Serbia
- Faculty of Medicine, University of Nis, Nis, Serbia
| | - Dragan Djordjevic
- Faculty of Medicine, University of Nis, Nis, Serbia
- Institute for Treatment and Rehabilitation Niska Banja, Nis, Serbia
| | - Nebojsa Antonijevic
- Clinic for Cardiology, University Clinical Centre of Serbia, Belgrade, Serbia
| | - Maja Koracevic
- Faculty of Medicine, University of Nis, Nis, Serbia
- Innovation Centre, University of Nis, Nis, Serbia
| | - Vesna Atanaskovic
- Department for Cardiovascular Diseases, University Clinical Centre Nis, Nis, Serbia
| | - Sonja Dakic
- Department for Cardiovascular Diseases, University Clinical Centre Nis, Nis, Serbia
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31
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Picard A, Berney X, Castillo-Armengol J, Tarussio D, Jan M, Sanchez-Archidona AR, Croizier S, Thorens B. Hypothalamic Irak4 is a genetically-controlled regulator of hypoglycemia-induced glucagon secretion. Mol Metab 2022; 61:101479. [PMID: 35339728 PMCID: PMC9046887 DOI: 10.1016/j.molmet.2022.101479] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Revised: 03/16/2022] [Accepted: 03/17/2022] [Indexed: 11/26/2022] Open
Abstract
OBJECTIVES Glucagon secretion to stimulate hepatic glucose production is a first line of defense against hypoglycemia. This response is triggered by so far incompletely characterized central hypoglycemia sensing mechanisms, which control autonomous nervous activity and hormone secretion. The objective of this study was to identify novel hypothalamic genes controlling insulin-induced glucagon secretion. METHODS To obtain new information about the mechanisms of hypothalamic hypoglycemia sensing, we combined genetic and transcriptomic analysis of the glucagon response to insulin-induced hypoglycemia in a panel of BXD recombinant inbred mice. RESULTS We identified two QTLs, on chromosome 8 and chromosome 15. We further investigated the role of Irak4 and Cpne8, both located in the chromosome 15 QTL, in C57BL/6J and DBA/2J mice, the BXD mouse parental strains. We found that the poor glucagon response of DBA/2J mice was associated with higher hypothalamic expression of Irak4, which encodes a kinase acting downstream of the interleukin-1 receptor (Il-1R), and of Il-ß when compared to C57BL/6J mice. We showed that intracerebroventricular administration of an Il-1R antagonist in DBA/2J restored insulin-induced glucagon secretion; this was associated with increased c-fos expression in the arcuate and paraventricular nuclei of the hypothalamus and with higher activation of both branches of the autonomous nervous system. Whole body inactivation of Cpne8, which encodes a Ca++-dependent regulator of membrane trafficking and exocytosis had, however, no impact on insulin-induced glucagon secretion. CONCLUSIONS Collectively, our data identify Irak4 as a genetically controlled regulator of hypoglycemia-activated hypothalamic neurons and glucagon secretion.
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Affiliation(s)
- Alexandre Picard
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Xavier Berney
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Judit Castillo-Armengol
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland; Novo Nordisk A/S, Måløv, Denmark
| | - David Tarussio
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Maxime Jan
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | | | - Sophie Croizier
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland
| | - Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, 1015 Lausanne, Switzerland.
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32
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Physiologic Insulin Resensitization as a Treatment Modality for Insulin Resistance Pathophysiology. Int J Mol Sci 2022; 23:ijms23031884. [PMID: 35163806 PMCID: PMC8836751 DOI: 10.3390/ijms23031884] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Revised: 01/28/2022] [Accepted: 02/03/2022] [Indexed: 12/10/2022] Open
Abstract
Prevalence of type 2 diabetes increased from 2.5% of the US population in 1990 to 10.5% in 2018. This creates a major public health problem, due to increases in long-term complications of diabetes, including neuropathy, retinopathy, nephropathy, skin ulcers, amputations, and atherosclerotic cardiovascular disease. In this review, we evaluated the scientific basis that supports the use of physiologic insulin resensitization. Insulin resistance is the primary cause of type 2 diabetes. Insulin resistance leads to increasing insulin secretion, leading to beta-cell exhaustion or burnout. This triggers a cascade leading to islet cell destruction and the long-term complications of type 2 diabetes. Concurrent with insulin resistance, the regular bursts of insulin from the pancreas become irregular. This has been treated by the precise administration of insulin more physiologically. There is consistent evidence that this treatment modality can reverse the diabetes-associated complications of neuropathy, diabetic ulcers, nephropathy, and retinopathy, and that it lowers HbA1c. In conclusion, physiologic insulin resensitization has a persuasive scientific basis, significant treatment potential, and likely cost benefits.
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33
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Li C, Chai X, Pan J, Huang J, Wu Y, Xue Y, Zhou W, Yang J, Zhu X, Zhao S. β-Hydroxybutyrate Alleviates Low Glucose-Induced Apoptosis via Modulation of ROS-Mediated p38 MAPK Signaling. J Mol Neurosci 2022; 72:923-938. [PMID: 35129799 DOI: 10.1007/s12031-022-01974-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2021] [Accepted: 01/14/2022] [Indexed: 11/26/2022]
Abstract
Hypoglycemia has emerged as a prominent complication in anti-diabetic drug therapy or negative energy balance of animals, which causes brain damage, cognitive impairment, and even death. Brain injury induced by hypoglycemia is closely related to oxidative stress and the production of reactive oxygen species (ROS). The intracellular accumulation of ROS leads to neuronal damage, even death. Ketone body β-hydroxybutyrate (BHBA) not only serves as alternative energy source for glucose in extrahepatic tissues, but is also involved in cellular signaling transduction. Previous studies showed that BHBA reduces apoptosis by inhibiting the excessive production of ROS and activation of caspase-3. However, the effects of BHBA on apoptosis induced by glucose deprivation and its related molecular mechanisms have been seldom reported. In the present study, PC12 cells and primary cortical neurons were used to establish a low glucose injury model. The effects of BHBA on the survival and apoptosis in a glucose deficient condition and related molecular mechanisms were investigated by using flow cytometry, immunofluorescence, and western blotting. PC12 cells were incubated with 1 mM glucose for 24 h as a low glucose cell model, in which ROS accumulation and cell mortality were significantly increased. After 24 h and 48 h treatment with different concentrations of BHBA (0 mM, 0.05 mM, 0.5 mM, 1 mM, 2 mM), ROS production was significantly inhibited. Moreover, cell apoptosis rate was decreased and survival rate was significantly increased in 1 mM and 2 mM BHBA groups. In primary cortical neurons, at 24 h after treatment with 2 mM BHBA, the injured length and branch of neurites were significantly improved. Meanwhile, the intracellular ROS level, the proportion of c-Fos+ cells, apoptosis rate, and nuclear translocation of NF-κB protein after treatment with BHBA were significantly decreased when compared with that in low glucose cells. Importantly, the expression of p38, p-p38, NF-κB, and caspase-3 were significantly decreased, while the expression of p-ERK was significantly increased in both PC12 cells and primary cortical neurons. Our results demonstrate that BHBA decreased the accumulation of intracellular ROS, and further inhibited cell apoptosis by mediating the p38 MAPK signaling pathway and caspase-3 apoptosis cascade during glucose deprivation. In addition, BHBA inhibited apoptosis by activating ERK phosphorylation and alleviated the damage of low glucose to PC12 cells and primary cortical neurons. These results provide new insight into the anti-apoptotic effect of BHBA in a glucose deficient condition and the related signaling cascade.
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Affiliation(s)
- Cixia Li
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Xuejun Chai
- College of Basic Medicine, Xi'An Medical University, Xi'An, Shaanxi, 710021, People's Republic of China
| | - Jiarong Pan
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Jian Huang
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Yongji Wu
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Yuhuan Xue
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Wentai Zhou
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China
| | - Jiping Yang
- College of Basic Medicine, Xi'An Medical University, Xi'An, Shaanxi, 710021, People's Republic of China
| | - Xiaoyan Zhu
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
| | - Shanting Zhao
- College of Veterinary Medicine, Northwest A&F University, Yangling, Shaanxi, 712100, People's Republic of China.
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Nakai-Shimoda H, Himeno T, Okawa T, Miura-Yura E, Sasajima S, Kato M, Yamada Y, Morishita Y, Tsunekawa S, Kato Y, Seino Y, Inoue R, Kondo M, Seino S, Naruse K, Kato K, Mizukami H, Nakamura J, Kamiya H. Kir6.2-deficient mice develop somatosensory dysfunction and axonal loss in the peripheral nerves. iScience 2022; 25:103609. [PMID: 35005553 PMCID: PMC8719014 DOI: 10.1016/j.isci.2021.103609] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Revised: 11/27/2021] [Accepted: 12/08/2021] [Indexed: 10/26/2022] Open
Abstract
Glucose-responsive ATP-sensitive potassium channels (KATP) are expressed in a variety of tissues including nervous systems. The depolarization of the membrane potential induced by glucose may lead to hyperexcitability of neurons and induce excitotoxicity. However, the roles of KATP in the peripheral nervous system (PNS) are poorly understood. Here, we determine the roles of KATP in the PNS using KATP-deficient (Kir6.2-deficient) mice. We demonstrate that neurite outgrowth of dorsal root ganglion (DRG) neurons was reduced by channel closers sulfonylureas. However, a channel opener diazoxide elongated the neurite. KATP subunits were expressed in mouse DRG, and expression of certain subunits including Kir6.2 was increased in diabetic mice. In Kir6.2-deficient mice, the current perception threshold, thermal perception threshold, and sensory nerve conduction velocity were impaired. Electron microscopy revealed a reduction of unmyelinated and small myelinated fibers in the sural nerves. In conclusion, KATP may contribute to the development of peripheral neuropathy.
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Affiliation(s)
- Hiromi Nakai-Shimoda
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Tatsuhito Himeno
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan.,Department of Innovative Diabetes Therapy, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Tetsuji Okawa
- Department of Endocrinology, Gifu Prefectural Tajimi Hospital, Tajimi 507-8522, Japan
| | - Emiri Miura-Yura
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Sachiko Sasajima
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Makoto Kato
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Yuichiro Yamada
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Yoshiaki Morishita
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Shin Tsunekawa
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Yoshiro Kato
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Yusuke Seino
- Division of Endocrinology and Metabolism, Department of Internal Medicine, Fujita Health University School of Medicine, Toyoake 470-1192, Aichi, Japan
| | - Rieko Inoue
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Masaki Kondo
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine, Department of Physiology and Cell Biology, Kobe University Graduate School of Medicine, Kobe 650-0047, Japan
| | - Keiko Naruse
- Department of Internal Medicine, Aichi Gakuin University School of Dentistry, Nagoya 464-0821, Japan
| | - Koichi Kato
- Department of Medicine, Aichi Gakuin University School of Pharmacy, Nagoya 464-8650, Japan
| | - Hiroki Mizukami
- Department of Pathology and Molecular Medicine, Hirosaki University Graduate School of Medicine, Hirosaki 036-8562, Japan
| | - Jiro Nakamura
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan.,Department of Innovative Diabetes Therapy, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
| | - Hideki Kamiya
- Division of Diabetes, Department of Internal Medicine, Aichi Medical University School of Medicine, Nagakute 480-1185, Japan
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35
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Thorens B. Neuronal regulation of glucagon secretion and gluconeogenesis. J Diabetes Investig 2022; 13:599-607. [PMID: 34989155 PMCID: PMC9017634 DOI: 10.1111/jdi.13745] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/24/2021] [Accepted: 01/02/2022] [Indexed: 11/29/2022] Open
Abstract
Hypoglycemia almost never develops in healthy individuals because multiple hypoglycemia sensing systems, located in the periphery and in the central nervous system trigger a coordinated counterregulatory hormonal response to restore normoglycemia. This involves not only the secretion of glucagon but also of epinephrine, norepinephrine, cortisol and growth hormone. Increased hepatic glucose production is also stimulated by direct autonomous nervous connections to the liver that stimulate glycogenolysis and gluconeogenesis. This counterregulatory response, however, becomes deregulated in a significant fraction of diabetic patients that receive insulin therapy. This leads to risk of developing hypoglycemic episodes, of increasing severity, which negatively impact the quality of life of the patients. How hypoglycemia is detected by the central nervous system is being actively investigated. Recent studies using novel molecular biological, optogenetic and chemogenetic techniques, allow the characterization of glucose sensing neurons, the mechanisms of hypoglycemia detection, the neuronal circuits in which they are integrated and the physiological responses they control. This review will discuss recent studies aimed at identifying central hypoglycemia sensing neuronal circuits, how neurons are activated by hypoglycemia, and how they restore normoglycemia.
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Affiliation(s)
- Bernard Thorens
- Center for Integrative Genomics, University of Lausanne, 1015, Lausanne, Switzerland
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36
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Kant R, Yadav P, Pratti M, Barnwal S. Hypoglycemia: Elucidating its circadian propensity and recovery time based on clinical parameters. CASPIAN JOURNAL OF INTERNAL MEDICINE 2022; 13:29-37. [PMID: 35178205 PMCID: PMC8797821 DOI: 10.22088/cjim.13.1.29] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/02/2021] [Revised: 02/15/2021] [Accepted: 02/24/2021] [Indexed: 10/31/2022]
Abstract
BACKGROUND Hypoglycemia is frequently associated with insulin therapy in diabetic patients; it leads to many short and long-term complications and even death if not addressed in time. This study was undertaken to observe the circadian propensity of hypoglycemia and its recovery time based on type 2 diabetes mellitus patients' clinical parameters. METHODS We included type 2 diabetes mellitus (DM) hospitalized patients with the exclusion of patients suffering from critical illness. Data were collected for a period of three months (September to November 2019). RESULTS A total of 120 patients were included, comprising 60% males and 40% females. Approximately 55% of patients had hypoglycemic episodes at around 12 am- 6 am. The most common comorbidity present in these patients was hypertension (43.3%, P=0.931). Anemia (OR-3.765, CI-1.350-5.500, P=0.011), retinopathy (OR 6.066, CI-2.031-8.113, P=0.001), and duration of DM (OR-6.266, CI-2.209-7.774, P=0.001) were significantly associated with the recovery time of hypoglycemia, around 50±14.14min in the elderly population of age 60-70. People with BMI 22.5- 27.5 Kg/m2 took around 45.66 ± 19.37 min to recover after treatment. CONCLUSION Time taken to recover from hypoglycemic episodes vary with age and BMI. Associated comorbidities such as anemia, retinopathy, and DM duration had a significant bearing on the time taken to recover from hypoglycemia. Recovery time was directly proportional to BMI, a new finding that needs further molecular level evaluation. Circadian propensity of hypoglycemia in these patients have been identified in the early morning hours of the day.
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Affiliation(s)
- Ravi Kant
- Department of Medicine, All India Institute of Medical Sciences, Rishikesh, India
| | - Poonam Yadav
- Center of Excellence in Nursing Education and Research, All India Institute of Medical Sciences, Rishikesh, India
| | - Madhuri Pratti
- Department of Medicine, All India Institute of Medical Sciences, Rishikesh, India
| | - Shruti Barnwal
- Department of Dermatology, Govt. Doon Medical College, Dehradun, India
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37
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Zhang Y, Zhang Y, Yang C, Ma C, Zhang M, Tang J. Facile immobilization of glucose oxidase with Cu 3(PO 4) 2·3H 2O for glucose biosensing via smartphone. Colloids Surf B Biointerfaces 2021; 210:112259. [PMID: 34883340 DOI: 10.1016/j.colsurfb.2021.112259] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Revised: 12/01/2021] [Accepted: 12/02/2021] [Indexed: 12/26/2022]
Abstract
A smartphone-based colorimetric platform for facile glucose detection was constructed below. First, glucose oxidase-Cu3(PO4)2·3H2O hybrid microflowers (GOx-HMFs) were facilely synthesized via biomineralization, which can react with glucose and 3,3',5,5'-tetramethylbenzidine to generate colored product. Next, the color information of product was real-time collected and processed via smartphone to realize accurate glucose detection. The as-constructed colorimetric platform based on GOx-HMFs and smartphone had wide linear range, high sensitivity and good selectivity for glucose detection, moreover, the detection process was convenient and efficient, which provided a new idea for glucose detection.
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Affiliation(s)
- Yuhang Zhang
- Institute of Hybrid Materials, College of Materials Science and Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071, People's Republic of China
| | - Yan Zhang
- Institute for Chemical Biology & Biosensing, College of Life Sciences, Qingdao University, 308 Ningxia Road, Qingdao 266071, People's Republic of China
| | - Chuankai Yang
- Institute of Hybrid Materials, College of Materials Science and Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071, People's Republic of China
| | - Chunyun Ma
- Institute of Hybrid Materials, College of Materials Science and Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071, People's Republic of China
| | - Miaorong Zhang
- Institute of Hybrid Materials, College of Materials Science and Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071, People's Republic of China.
| | - Jianguo Tang
- Institute of Hybrid Materials, College of Materials Science and Engineering, Qingdao University, 308 Ningxia Road, Qingdao 266071, People's Republic of China
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38
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Hicks R, Marks BE, Oxman R, Moheet A. Spontaneous and iatrogenic hypoglycemia in cystic fibrosis. JOURNAL OF CLINICAL AND TRANSLATIONAL ENDOCRINOLOGY 2021; 26:100267. [PMID: 34745906 PMCID: PMC8551648 DOI: 10.1016/j.jcte.2021.100267] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/31/2021] [Revised: 10/02/2021] [Accepted: 10/10/2021] [Indexed: 12/12/2022]
Abstract
Spontaneous episodes of hypoglycemia can occur in people with cystic fibrosis (CF) without diabetes, who are not on glucose lowering medications. Spontaneous hypoglycemia in CF could occur both in the fasting or postprandial state (reactive hypoglycemia). The pathophysiology of fasting hypoglycemia is thought to be related to malnutrition and increased energy expenditure in the setting of inflammation and acute infections. Reactive hypoglycemia is thought to be due to impaired first phase insulin release in response to a glucose load, followed by a delayed and extended second phase insulin secretion; ineffective counterregulatory response to dropping glucose levels may also play a role. The overall prevalence of spontaneous hypoglycemia varies from 7 to 69% as examined with oral glucose tolerance test (OGTT) or with continuous glucose monitoring (CGM) under free living conditions. Spontaneous hypoglycemia in CF is associated with worse lung function, higher hospitalization rates, and worse clinical status. In addition, patients with CF related diabetes on glucose-lowering therapies are at risk for iatrogenic hypoglycemia. In this article, we will review the pathophysiology, prevalence, risk factors, clinical implications, and management of spontaneous and iatrogenic hypoglycemia in patients with CF.
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Affiliation(s)
- Rebecca Hicks
- Division of Pediatric Endocrinology, David Geffen School of Medicine, UCLA, 10833 Le Conte Ave., MDCC 22-315, Los Angeles, CA, USA
| | - Brynn E Marks
- Division of Endocrinology and Diabetes, Children's National Hospital, 111 Michigan Avenue NW, Washington, DC, USA.,Department of Pediatrics, George Washington University School of Medicine & Health Sciences, Ross Hall, 2300 Eye Street, NW, Washington, DC, USA
| | - Rachael Oxman
- Division of Endocrinology, Diabetes and Metabolism, UCLA Santa Monica Medical Center, 2020 Santa Monica Boulevard, Suite 550, Santa Monica, CA, USA
| | - Amir Moheet
- Division of Endocrinology, Diabetes and Metabolism, University of Minnesota, 420 Delaware Street SE, MMC 101, Minneapolis, MN, USA
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Asadi F, Dhanvantari S. Pathways of Glucagon Secretion and Trafficking in the Pancreatic Alpha Cell: Novel Pathways, Proteins, and Targets for Hyperglucagonemia. Front Endocrinol (Lausanne) 2021; 12:726368. [PMID: 34659118 PMCID: PMC8511682 DOI: 10.3389/fendo.2021.726368] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Accepted: 09/13/2021] [Indexed: 12/15/2022] Open
Abstract
Patients with diabetes mellitus exhibit hyperglucagonemia, or excess glucagon secretion, which may be the underlying cause of the hyperglycemia of diabetes. Defective alpha cell secretory responses to glucose and paracrine effectors in both Type 1 and Type 2 diabetes may drive the development of hyperglucagonemia. Therefore, uncovering the mechanisms that regulate glucagon secretion from the pancreatic alpha cell is critical for developing improved treatments for diabetes. In this review, we focus on aspects of alpha cell biology for possible mechanisms for alpha cell dysfunction in diabetes: proglucagon processing, intrinsic and paracrine control of glucagon secretion, secretory granule dynamics, and alterations in intracellular trafficking. We explore possible clues gleaned from these studies in how inhibition of glucagon secretion can be targeted as a treatment for diabetes mellitus.
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Affiliation(s)
- Farzad Asadi
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
- Program in Metabolism and Diabetes, Lawson Health Research Institute, London, ON, Canada
| | - Savita Dhanvantari
- Department of Pathology and Laboratory Medicine, Western University, London, ON, Canada
- Program in Metabolism and Diabetes, Lawson Health Research Institute, London, ON, Canada
- Imaging Research Program, Lawson Health Research Institute, London, ON, Canada
- Department of Medical Biophysics, Western University, London, ON, Canada
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40
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Tavares G, Martins FO, Melo BF, Matafome P, Conde SV. Peripheral Dopamine Directly Acts on Insulin-Sensitive Tissues to Regulate Insulin Signaling and Metabolic Function. Front Pharmacol 2021; 12:713418. [PMID: 34566639 PMCID: PMC8458637 DOI: 10.3389/fphar.2021.713418] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2021] [Accepted: 07/26/2021] [Indexed: 12/25/2022] Open
Abstract
Dopamine is a key regulator of glucose metabolism in the central nervous system. However, dopamine is also present in the periphery and may have direct effects on insulin-sensitive tissues. Dopamine receptor 2 (D2R) agonist bromocriptine is a FDA-approved drug for type 2 diabetes. Herein, we explored the role of peripheral dopamine and its receptors in regulating glucose uptake and metabolism on insulin-sensitive tissues. Peripheral dopamine effect in [3H]2-deoxyglucose uptake in insulin-sensitive tissues was tested in vivo in rats. Direct effects on [3H]2-deoxyglucose uptake, insulin receptor phosphorylation, and regulation of metabolic function were tested ex vivo in the liver, soleus muscle, and white and brown adipose tissues. Bromocriptine and the antagonists domperidone, D2R antagonist, and haloperidol, antagonist of both dopamine receptor 1 (D1R) and D2R, were used to disclose dopamine receptors’ involvement. Peripheral dopamine increases glucose uptake in vivo. Ex vivo, only dopamine increased glucose uptake in the soleus, while bromocriptine increased it in the liver; the effects were reverted by haloperidol and domperidone, respectively. In adipose tissue, domperidone reverted dopamine- and bromocriptine-mediated potentiation of insulin-induced glucose uptake, but in turn increased the insulin receptor, Akt, AMPK, HSL, ACC, and ACL, phosphorylation. In the soleus muscle, AMPK-phosphorylation increased with bromocriptine and dopamine whose effects were suppressed by domperidone and haloperidol. In conclusion, peripheral dopamine stimulates glucose uptake with its receptors being differentially involved in glucose uptake in insulin-sensitive tissues. Dopamine also has a role in lipid metabolism in white adipose tissue. Altogether, these results suggest that peripheral modulation of the dopaminergic system should be further evaluated as a putative therapeutic approach for metabolic disorders.
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Affiliation(s)
- Gabriela Tavares
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal.,Institute of Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, Coimbra, Portugal.,Clinical-Academic Center of Coimbra, Coimbra, Portugal
| | - Fatima O Martins
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Bernardete F Melo
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
| | - Paulo Matafome
- Institute of Clinical and Biomedical Research (iCBR), Faculty of Medicine, University of Coimbra, Coimbra, Portugal.,Center for Innovative Biomedicine and Biotechnology (CIBB), University of Coimbra, Coimbra, Portugal.,Clinical-Academic Center of Coimbra, Coimbra, Portugal.,Coimbra Health School, Instituto Politécnico de Coimbra, Coimbra, Portugal
| | - Silvia V Conde
- CEDOC, NOVA Medical School, Faculdade de Ciências Médicas, Universidade Nova de Lisboa, Lisboa, Portugal
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Chen P, Wu X, Gu X, Han J, Xue M, Liang X. FoxO1 in Micropterus salmoides: Molecular characterization and its roles in glucose metabolism by glucose or insulin-glucose loading. Gen Comp Endocrinol 2021; 310:113811. [PMID: 33979571 DOI: 10.1016/j.ygcen.2021.113811] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2020] [Revised: 04/15/2021] [Accepted: 05/07/2021] [Indexed: 12/18/2022]
Abstract
Forkhead box O1 (FoxO1), a nuclear transcription factor, plays an important role in insulin-mediated glucose metabolism. In this study, FoxO1 gene from largemouth bass (Micropterus salmoides) was cloned and characterized, and its effects on hepatic glucose metabolism regulated by insulin-AKT pathway were investigated in response to glucose or insulin-glucose injection. The full-length cDNA of FoxO1 consisted of 2541 bp and encoded 680 amino acids. Sequence alignments and phylogenetic analysis revealed that FoxO1 exhibited a high degree of conservation among teleost, retaining one forkhead domain, one transactivation domain, and three phosphorylation sites. FoxO1 mRNA was expressed in a wide range of tissues, and high in the brain and liver. Glucose loading resulted in persistent hyperglycemia, and plasma insulin levels remained unchanged except at 1 h. After the insulin-glucose injection, insulin levels were significantly elevated and glucose levels recovered to the basal value after 6 h, which indicated insufficient insulin secretion caused persistent hyperglycemia in this species. Compared with the glucose injection group, transcript levels and enzyme activities of hepatic glycolysis-related genes (GK and PK) were significantly activated, and gluconeogenesis-related genes (PEPCK and G6Pase) were significantly depressed at 3 h after the insulin-glucose injection. Besides, phosphorylation of AKT-FoxO1 pathway was significantly activated. Therefore, insulin improved glucose metabolism by activating the AKT-FoxO1 phosphorylation to decrease hyperglycemia stress after the meal, which indicated insufficient insulin secretion was the reason for glucose intolerance in largemouth bass. Meanwhile, conserved S267 and S329 phosphorylation sites of FoxO1 were confirmed to be regulated by AKT and mediated the glucose metabolism. In conclusion, activation of insulin-AKT-FoxO1 pathway improved glucose tolerance through mediating glucose metabolism in largemouth bass.
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Affiliation(s)
- Pei Chen
- National Aquafeed Safety Assessment Center, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xiufeng Wu
- National Aquafeed Safety Assessment Center, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Xu Gu
- National Aquafeed Safety Assessment Center, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, China
| | - Juan Han
- Institute of Food and Nutrition Development, Ministry of Agriculture and Rural Affairs, Beijing 100081, China
| | - Min Xue
- National Aquafeed Safety Assessment Center, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
| | - Xiaofang Liang
- National Aquafeed Safety Assessment Center, Institute of Feed Research, Chinese Academy of Agricultural Sciences, Beijing 100081, China.
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Slow but Steady-The Responsiveness of Sympathoadrenal System to a Hypoglycemic Challenge in Ketogenic Diet-Fed Rats. Nutrients 2021; 13:nu13082627. [PMID: 34444787 PMCID: PMC8398867 DOI: 10.3390/nu13082627] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/06/2021] [Revised: 07/25/2021] [Accepted: 07/28/2021] [Indexed: 12/16/2022] Open
Abstract
The sympathoadrenal counterregulatory response to hypoglycemia is critical for individuals with type 1 diabetes due to impaired ability to produce glucagon. Ketogenic diets (KD) are an increasingly popular diabetes management tool; however, the effects of KD on the sympathoadrenal response are largely unknown. Here, we determined the effects of KD-induced ketosis on the sympathoadrenal response to a single insulin-induced hypoglycemic challenge. We investigated how a 3 week KD feeding regimen affected the main components of the sympathoadrenal counterregulatory response: adrenal sympathetic nerve activity (ASNA), adrenal gland activity, plasma epinephrine, and brainstem glucose-responsive C1 neuronal activation in anesthetized, nondiabetic male Sprague-Dawley rats. Rats on KD had similar blood glucose (BG) levels and elevated ketone body β-hydroxybutyrate (BHB) levels compared to the control Chow diet group. All KD rats responded to hypoglycemia with a robust increase in ASNA, which was initiated at significantly lower BG levels compared to Chow-fed rats. The delay in hypoglycemia-induced ASNA increase was concurrent with rapid disappearance of BHB from cerebral and peripheral circulation. Adrenal gland activity paralleled epinephrine and ASNA response. Overall, KD-induced ketosis was associated with initiation of the sympathoadrenal response at lower blood glucose levels; however, the magnitude of the response was not diminished.
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Borgmann D, Ciglieri E, Biglari N, Brandt C, Cremer AL, Backes H, Tittgemeyer M, Wunderlich FT, Brüning JC, Fenselau H. Gut-brain communication by distinct sensory neurons differently controls feeding and glucose metabolism. Cell Metab 2021; 33:1466-1482.e7. [PMID: 34043943 PMCID: PMC8280952 DOI: 10.1016/j.cmet.2021.05.002] [Citation(s) in RCA: 77] [Impact Index Per Article: 25.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2020] [Revised: 02/23/2021] [Accepted: 05/03/2021] [Indexed: 01/26/2023]
Abstract
Sensory neurons relay gut-derived signals to the brain, yet the molecular and functional organization of distinct populations remains unclear. Here, we employed intersectional genetic manipulations to probe the feeding and glucoregulatory function of distinct sensory neurons. We reconstruct the gut innervation patterns of numerous molecularly defined vagal and spinal afferents and identify their downstream brain targets. Bidirectional chemogenetic manipulations, coupled with behavioral and circuit mapping analysis, demonstrated that gut-innervating, glucagon-like peptide 1 receptor (GLP1R)-expressing vagal afferents relay anorexigenic signals to parabrachial nucleus neurons that control meal termination. Moreover, GLP1R vagal afferent activation improves glucose tolerance, and their inhibition elevates blood glucose levels independent of food intake. In contrast, gut-innervating, GPR65-expressing vagal afferent stimulation increases hepatic glucose production and activates parabrachial neurons that control normoglycemia, but they are dispensable for feeding regulation. Thus, distinct gut-innervating sensory neurons differentially control feeding and glucoregulatory neurocircuits and may provide specific targets for metabolic control.
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Affiliation(s)
- Diba Borgmann
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Translational Neurocircuitry Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Center for Anatomy II, Neuroanatomy, University Hospital Cologne, Joseph-Stelzmann Str. 9, 50937 Cologne, Germany
| | - Elisa Ciglieri
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50937 Cologne, Germany
| | - Nasim Biglari
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Claus Brandt
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Anna Lena Cremer
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Heiko Backes
- Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Strasse 50, 50931 Cologne, Germany
| | - Marc Tittgemeyer
- Translational Neurocircuitry Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Straße 26, Cologne 50931, Germany
| | - F Thomas Wunderlich
- Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50937 Cologne, Germany; Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Strasse 50, 50931 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Straße 26, Cologne 50931, Germany; Center of Molecular Medicine Cologne (CMMC), University of Cologne, Robert-Koch-Straße 21, 50931 Cologne, Germany
| | - Jens C Brüning
- Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50937 Cologne, Germany; Max Planck Institute for Metabolism Research, Department of Neuronal Control of Metabolism, Gleueler Strasse 50, 50931 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Straße 26, Cologne 50931, Germany; Center of Molecular Medicine Cologne (CMMC), University of Cologne, Robert-Koch-Straße 21, 50931 Cologne, Germany
| | - Henning Fenselau
- Synaptic Transmission in Energy Homeostasis Group, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany; Center for Endocrinology, Diabetes and Preventive Medicine (CEDP), University Hospital Cologne, Kerpener Strasse 26, 50937 Cologne, Germany; Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD), University of Cologne, Joseph-Stelzmann-Straße 26, Cologne 50931, Germany.
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Almby KE, Lundqvist MH, Abrahamsson N, Kvernby S, Fahlström M, Pereira MJ, Gingnell M, Karlsson FA, Fanni G, Sundbom M, Wiklund U, Haller S, Lubberink M, Wikström J, Eriksson JW. Effects of Gastric Bypass Surgery on the Brain: Simultaneous Assessment of Glucose Uptake, Blood Flow, Neural Activity, and Cognitive Function During Normo- and Hypoglycemia. Diabetes 2021; 70:1265-1277. [PMID: 33674408 PMCID: PMC8275889 DOI: 10.2337/db20-1172] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 02/25/2021] [Indexed: 12/15/2022]
Abstract
While Roux-en-Y gastric bypass (RYGB) surgery in obese individuals typically improves glycemic control and prevents diabetes, it also frequently causes asymptomatic hypoglycemia. Previous work showed attenuated counterregulatory responses following RYGB. The underlying mechanisms as well as the clinical consequences are unclear. In this study, 11 subjects without diabetes with severe obesity were investigated pre- and post-RYGB during hyperinsulinemic normo-hypoglycemic clamps. Assessments were made of hormones, cognitive function, cerebral blood flow by arterial spin labeling, brain glucose metabolism by 18F-fluorodeoxyglucose (FDG) positron emission tomography, and activation of brain networks by functional MRI. Post- versus presurgery, we found a general increase of cerebral blood flow but a decrease of total brain FDG uptake during normoglycemia. During hypoglycemia, there was a marked increase in total brain FDG uptake, and this was similar for post- and presurgery, whereas hypothalamic FDG uptake was reduced during hypoglycemia. During hypoglycemia, attenuated responses of counterregulatory hormones and improvements in cognitive function were seen postsurgery. In early hypoglycemia, there was increased activation post- versus presurgery of neural networks in brain regions implicated in glucose regulation, such as the thalamus and hypothalamus. The results suggest adaptive responses of the brain that contribute to lowering of glycemia following RYGB, and the underlying mechanisms should be further elucidated.
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Affiliation(s)
- Kristina E Almby
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Martin H Lundqvist
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Niclas Abrahamsson
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Sofia Kvernby
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Markus Fahlström
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Maria J Pereira
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Malin Gingnell
- Department of Neurosciences and Department of Psychology, Uppsala University, Uppsala, Sweden
| | - F Anders Karlsson
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Giovanni Fanni
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
| | - Magnus Sundbom
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Urban Wiklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Sven Haller
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
- Faculty of Medicine, University of Geneva, Geneva, Switzerland
| | - Mark Lubberink
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Johan Wikström
- Department of Surgical Sciences, Uppsala University, Uppsala, Sweden
| | - Jan W Eriksson
- Department of Medical Sciences, Clinical Diabetes and Metabolism, Uppsala University, Uppsala, Sweden
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Abstract
The discovery of insulin and its subsequent mass manufacture transformed the lives of people with type 1 and 2 diabetes. Insulin, however, was a drug with a 'dark side'. It brought with it the risk of iatrogenic hypoglycaemia. In this short review, the cellular consequences of recurrent hypoglycaemia, with a particular focus on the brain, are discussed. Using the ventromedial hypothalamus as an exemplar, this review highlights how recurrent hypoglycaemia has an impact on the specialised cells in the brain that are critical to the regulation of glucose homeostasis and the counterregulatory response to hypoglycaemia. In these cells, recurrent hypoglycaemia initiates a series of adaptations that ensure that they are more resilient to subsequent hypoglycaemia, but this leads to impaired hypoglycaemia awareness and a paradoxical increased risk of severe hypoglycaemia. This review also highlights how hypoglycaemia, as an oxidative stressor, may also exacerbate chronic hyperglycaemia-induced increases in oxidative stress and inflammation, leading to damage to vulnerable brain regions (and other end organs) and accelerating cognitive decline. Pre-clinical research indicates that glucose recovery following hypoglycaemia is considered a period where reactive oxygen species generation and oxidative stress are pronounced and can exacerbate the longer-term consequence of chronic hypoglycaemia. It is proposed that prior glycaemic control, hypoglycaemia and the degree of rebound hyperglycaemia interact synergistically to accelerate oxidative stress and inflammation, which may explain why increased glycaemic variability is now increasingly considered a risk factor for the complications of diabetes.
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Affiliation(s)
- Rory J McCrimmon
- Systems Medicine, School of Medicine, University of Dundee, Ninewells Hospital and Medical School, Dundee, UK.
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Hall M, Walicka M, Panczyk M, Traczyk I. Metabolic Parameters in Patients with Suspected Reactive Hypoglycemia. J Pers Med 2021; 11:jpm11040276. [PMID: 33916952 PMCID: PMC8067537 DOI: 10.3390/jpm11040276] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2021] [Revised: 04/01/2021] [Accepted: 04/04/2021] [Indexed: 12/15/2022] Open
Abstract
Background: It remains unclear whether reactive hypoglycemia (RH) is a disorder caused by improper insulin secretion, result of eating habits that are not nutritionally balanced or whether it is a psychosomatic disorder. The aim of this study was to investigate metabolic parameters in patients admitted to the hospital with suspected RH. Methods: The study group (SG) included non-diabetic individuals with symptoms consistent with RH. The control group (CG) included individuals without hypoglycemic symptoms and any documented medical history of metabolic disorders. In both groups the following investigations were performed: fasting glucose and insulin levels, Homeostatic Model Assessment for Insulin Resistance (HOMA-IR), 75 g five-hour Oral Glucose Tolerance Test (OGTT) with an assessment of glucose and insulin and lipid profile evaluation. Additionally, Mixed Meal Tolerance Test (MMTT) was performed in SG. Results from OGTT and MMTT were analyzed in line with the non-standardized RH diagnostic criteria. Results: Forty subjects have been enrolled into SG. Twelve (30%) of those patients had hypoglycemic symptoms and glucose level ≤55 mg/dL during five-hour OGTT and have been diagnosed with RH. Ten (25%) subjects manifested hypoglycemic like symptoms without significant glucose decline. Patients with diagnosed RH had statistically significantly lower mean glucose at first (92.1 ± 37.9 mg/dL vs. 126.4 ± 32.5 mg/dL; LSD test: p < 0.001) and second (65.6 ± 19.3 mg/dL vs. 92.6 ± 19.3 mg/dL; LSD test: p < 0.001) hour of OGTT and insulin value (22.7 ± 10.9 lU/mL vs. 43.4 ± 35.0 lU/mL; LSD test: p < 0.001) at second hour of OGTT compared to the patients who did not meet the criteria of RH. Seventeen (43%) subjects from SG reported symptoms suggesting hypoglycemia during MMTT but none of them had glucose value lower than ≤55 mg/dL (68.7 ± 4.7 mg/dL). From the entire lipid profile, only mean total cholesterol value was significantly higher (p = 0.024) in SG in comparison with CG but did not exceed standard reference range. Conclusions: No metabolic disturbances have been observed in patients with diagnosed reactive hypoglycemia. Hyperinsulinemia has not been associated with glycemic declines in patients with this condition. Occurrence of pseudohypoglicemic symptoms and lower glucose value was more common after ingestion of glucose itself rather than after ingestion of a balanced meal. This could suggest an important role that nutritionally balanced diet may play in maintaining correct glucose and insulin levels in the postprandial period.
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Affiliation(s)
- Marianna Hall
- Department of Human Nutrition, Faculty of Health Sciences, Medical University of Warsaw, 01-445 Warsaw, Poland;
- Department of Internal Diseases, Endocrinology and Diabetology, Central Clinical Hospital of the Ministry of Internal Affairs and Administration in Warsaw, 02-507 Warsaw, Poland;
- Correspondence:
| | - Magdalena Walicka
- Department of Internal Diseases, Endocrinology and Diabetology, Central Clinical Hospital of the Ministry of Internal Affairs and Administration in Warsaw, 02-507 Warsaw, Poland;
- Department of Human Epigenetics, Mossakowski Medical Research Institute Polish Academy of Sciences, 02-106 Warsaw, Poland
| | - Mariusz Panczyk
- Department of Education and Research in Health Sciences, Faculty of Health Sciences, Medical University of Warsaw, 02-091 Warsaw, Poland;
| | - Iwona Traczyk
- Department of Human Nutrition, Faculty of Health Sciences, Medical University of Warsaw, 01-445 Warsaw, Poland;
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Campbell-Thompson M, Butterworth EA, Boatwright JL, Nair MA, Nasif LH, Nasif K, Revell AY, Riva A, Mathews CE, Gerling IC, Schatz DA, Atkinson MA. Islet sympathetic innervation and islet neuropathology in patients with type 1 diabetes. Sci Rep 2021; 11:6562. [PMID: 33753784 PMCID: PMC7985489 DOI: 10.1038/s41598-021-85659-8] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/30/2020] [Accepted: 03/04/2021] [Indexed: 02/07/2023] Open
Abstract
Dysregulation of glucagon secretion in type 1 diabetes (T1D) involves hypersecretion during postprandial states, but insufficient secretion during hypoglycemia. The sympathetic nervous system regulates glucagon secretion. To investigate islet sympathetic innervation in T1D, sympathetic tyrosine hydroxylase (TH) axons were analyzed in control non-diabetic organ donors, non-diabetic islet autoantibody-positive individuals (AAb), and age-matched persons with T1D. Islet TH axon numbers and density were significantly decreased in AAb compared to T1D with no significant differences observed in exocrine TH axon volume or lengths between groups. TH axons were in close approximation to islet α-cells in T1D individuals with long-standing diabetes. Islet RNA-sequencing and qRT-PCR analyses identified significant alterations in noradrenalin degradation, α-adrenergic signaling, cardiac β-adrenergic signaling, catecholamine biosynthesis, and additional neuropathology pathways. The close approximation of TH axons at islet α-cells supports a model for sympathetic efferent neurons directly regulating glucagon secretion. Sympathetic islet innervation and intrinsic adrenergic signaling pathways could be novel targets for improving glucagon secretion in T1D.
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Affiliation(s)
- Martha Campbell-Thompson
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, 32610, USA. .,Department of Biomedical Engineering, College of Engineering, University of Florida, Gainesville, FL, 32610, USA.
| | - Elizabeth A Butterworth
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - J Lucas Boatwright
- Bioinformatics Core, Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL, 32610, USA
| | - Malavika A Nair
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Lith H Nasif
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Kamal Nasif
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Andy Y Revell
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Alberto Riva
- Bioinformatics Core, Interdisciplinary Center for Biotechnology Research, University of Florida, Gainesville, FL, 32610, USA
| | - Clayton E Mathews
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Ivan C Gerling
- Department of Medicine-Endocrinology, University of Tennessee Health Science Center, Memphis, TN, 38163, USA
| | - Desmond A Schatz
- Department of Pediatrics, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
| | - Mark A Atkinson
- Department of Pathology, Immunology, and Laboratory Medicine, College of Medicine, University of Florida, Gainesville, FL, 32610, USA.,Department of Pediatrics, College of Medicine, University of Florida, Gainesville, FL, 32610, USA
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Lundqvist MH, Almby K, Wiklund U, Abrahamsson N, Kamble PG, Pereira MJ, Eriksson JW. Altered hormonal and autonomic nerve responses to hypo- and hyperglycaemia are found in overweight and insulin-resistant individuals and may contribute to the development of type 2 diabetes. Diabetologia 2021; 64:641-655. [PMID: 33241460 PMCID: PMC7864814 DOI: 10.1007/s00125-020-05332-z] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/16/2020] [Accepted: 10/01/2020] [Indexed: 12/27/2022]
Abstract
AIMS/HYPOTHESIS Results from animal models and some clinical work suggest a role for the central nervous system (CNS) in glucose regulation and type 2 diabetes pathogenesis by modulation of glucoregulatory hormones and the autonomic nervous system (ANS). The aim of this study was to characterise the neuroendocrine response to various glucose concentrations in overweight and insulin-resistant individuals compared with lean individuals. METHODS Overweight/obese (HI, n = 15, BMI ≥27.0 kg/m2) and lean (LO, n = 15, BMI <27.0 kg/m2) individuals without diabetes underwent hyperinsulinaemic euglycaemic-hypoglycaemic clamps and hyperglycaemic clamps on two separate occasions with measurements of hormones, Edinburgh Hypoglycaemic Symptom Scale (ESS) score and heart rate variability (HRV). Statistical methods included groupwise comparisons with Mann-Whitney U tests, multilinear regressions and linear mixed models between neuroendocrine responses and continuous metabolic variables. RESULTS During hypoglycaemic clamps, there was an elevated cortisol response in HI vs LO (median ΔAUC 12,383 vs 4793 nmol/l × min; p = 0.050) and a significantly elevated adrenocorticotropic hormone (ACTH) response in HI vs LO (median ΔAUC 437.3 vs 162.0 nmol/l × min; p = 0.021). When adjusting for clamp glucose levels, obesity (p = 0.033) and insulin resistance (p = 0.009) were associated with elevated glucagon levels. By contrast, parasympathetic activity was less suppressed in overweight individuals at the last stage of hypoglycaemia compared with euglycaemia (high-frequency power of HRV, p = 0.024). M value was the strongest predictor for the ACTH and PHF responses, independent of BMI and other variables. There was a BMI-independent association between the cortisol response and ESS score response (p = 0.024). During hyperglycaemic clamps, overweight individuals displayed less suppression of glucagon levels (median ΔAUC -63.4% vs -73.0%; p = 0.010) and more suppression of sympathetic relative to parasympathetic activity (low-frequency/high-frequency power, p = 0.011). CONCLUSIONS/INTERPRETATION This study supports the hypothesis that altered responses of insulin-antagonistic hormones and the ANS to glucose fluctuations occur in overweight and insulin-resistant individuals, and that these responses are probably partly mediated by the CNS. Their potential role in development of type 2 diabetes needs to be addressed in future research. Graphical abstract.
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Affiliation(s)
| | - Kristina Almby
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Urban Wiklund
- Department of Radiation Sciences, Biomedical Engineering, Umeå University, Umeå, Sweden
| | | | - Prasad G Kamble
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Maria J Pereira
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | - Jan W Eriksson
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden.
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Mannal N, Kleiner K, Fauler M, Dougalis A, Poetschke C, Liss B. Multi-Electrode Array Analysis Identifies Complex Dopamine Responses and Glucose Sensing Properties of Substantia Nigra Neurons in Mouse Brain Slices. Front Synaptic Neurosci 2021; 13:635050. [PMID: 33716704 PMCID: PMC7952765 DOI: 10.3389/fnsyn.2021.635050] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2020] [Accepted: 01/08/2021] [Indexed: 12/16/2022] Open
Abstract
Dopaminergic (DA) midbrain neurons within the substantia nigra (SN) display an autonomous pacemaker activity that is crucial for dopamine release and voluntary movement control. Their progressive degeneration is a hallmark of Parkinson's disease. Their metabolically demanding activity-mode affects Ca2+ homeostasis, elevates metabolic stress, and renders SN DA neurons particularly vulnerable to degenerative stressors. Accordingly, their activity is regulated by complex mechanisms, notably by dopamine itself, via inhibitory D2-autoreceptors and the neuroprotective neuronal Ca2+ sensor NCS-1. Analyzing regulation of SN DA neuron activity-pattern is complicated by their high vulnerability. We studied this activity and its control by dopamine, NCS-1, and glucose with extracellular multi-electrode array (MEA) recordings from midbrain slices of juvenile and adult mice. Our tailored MEA- and spike sorting-protocols allowed high throughput and long recording times. According to individual dopamine-responses, we identified two distinct SN cell-types, in similar frequency: dopamine-inhibited and dopamine-excited neurons. Dopamine-excited neurons were either silent in the absence of dopamine, or they displayed pacemaker-activities, similar to that of dopamine-inhibited neurons. Inhibition of pacemaker-activity by dopamine is typical for SN DA neurons, and it can undergo prominent desensitization. We show for adult mice, that the number of SN DA neurons with desensitized dopamine-inhibition was increased (~60–100%) by a knockout of NCS-1, or by prevention of NCS-1 binding to D2-autoreceptors, while time-course and degrees of desensitization were not altered. The number of neurons with desensitized D2-responses was also higher (~65%) at high glucose-levels (25 mM), compared to lower glucose (2.5 mM), while again desensitization-kinetics were unaltered. However, spontaneous firing-rates were significantly higher at high glucose-levels (~20%). Moreover, transient glucose-deprivation (1 mM) induced a fast and fully-reversible pacemaker frequency reduction. To directly address and quantify glucose-sensing properties of SN DA neurons, we continuously monitored their electrical activity, while altering extracellular glucose concentrations stepwise from 0.5 mM up to 25 mM. SN DA neurons were excited by glucose, with EC50 values ranging from 0.35 to 2.3 mM. In conclusion, we identified a novel, common subtype of dopamine-excited SN neurons, and a complex, joint regulation of dopamine-inhibited neurons by dopamine and glucose, within the range of physiological brain glucose-levels.
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Affiliation(s)
- Nadja Mannal
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | | | - Michael Fauler
- Institute of Applied Physiology, University of Ulm, Ulm, Germany
| | | | | | - Birgit Liss
- Institute of Applied Physiology, University of Ulm, Ulm, Germany.,Linacre and New College, University of Oxford, Oxford, United Kingdom
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The Characterization of Sex Differences in Hypoglycemia-Induced Activation of HPA Axis on the Transcriptomic Level. Cell Mol Neurobiol 2021; 42:1523-1542. [PMID: 33544274 DOI: 10.1007/s10571-021-01043-0] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Accepted: 01/11/2021] [Indexed: 11/27/2022]
Abstract
Activation of the hypothalamic-pituitary-adrenal (HPA) axis using an insulin tolerance test (ITT) is a medical diagnostic procedure that is frequently used in humans to assess the HPA and growth-hormone (GH) axes. Whether sex differences exist in the response to ITT stress is unknown. Thus, investigations into the analysis of transcripts during activation of the HPA axis in response to hypoglycemia have revealed the underlying influences of sex in signaling pathways that stimulate the HPA axis. We assessed four time points of ITT application in Balb/c mice. After insulin injection, expression levels of 192 microRNAs and 41 mRNAs associated with the HPA, GH and hypothalamic-pituitary-gonadal (HPG) axes were determined by real-time RT-PCR in the hypothalamus, pituitary and adrenal tissues, as well as blood samples (Raw data accession: https://drive.google.com/drive/folders/10qI00NAtjxOepcNKxSJnQbJeBFa6zgHK?usp=sharing ). Although the ITT is commonly used as a gold standard for evaluating the HPA axis, we found completely different responses between males and females with respect to activation of the HPA axis. While activation of several transcripts in the hypothalamus and pituitary was observed after performing the ITT in males within 10 min, females responded via the pituitary and adrenal immediately and durably over 40 min. Additionally, we found that microRNA alterations precede mRNA responses in the HPA axis. Furthermore, robust changes in the levels of several transcripts including Avpr1b and Avpr2 observed at all time points strongly suggest that transcriptional control of these genes occurs mostly via differential signaling in pituitary and blood between males and females. Male and female HPA axis responses to ITT involve a number of sophisticated regulatory signaling pathways of miRNAs and mRNAs. Our results highlight the first robust markers in several layers of HPA, HPG and GH axis involved in ITT/hypoglycemia stress-induced dynamics.
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