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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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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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Macon EL, Devore MH, Lin YK, Music MB, Wooten M, McMullen CA, Woodcox AM, Marksbury AR, Beckner Z, Patel BV, Schoeder LA, Iles AN, Fisher SJ. Current and future therapies to treat impaired awareness of hypoglycemia. Front Pharmacol 2023; 14:1271814. [PMID: 37942482 PMCID: PMC10628050 DOI: 10.3389/fphar.2023.1271814] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2023] [Accepted: 10/05/2023] [Indexed: 11/10/2023] Open
Abstract
In order to achieve optimal glycemic control, intensive insulin regimes are needed for individuals with Type 1 Diabetes (T1D) and insulin-dependent Type 2 Diabetes (T2D). Unfortunately, intensive glycemic control often results in insulin-induced hypoglycemia. Moreover, recurrent episodes of hypoglycemia result in both the loss of the characteristic warning symptoms associated with hypoglycemia and an attenuated counterregulatory hormone responses. The blunting of warning symptoms is known as impaired awareness of hypoglycemia (IAH). Together, IAH and the loss of the hormonal response is termed hypoglycemia associated autonomic failure (HAAF). IAH is prevalent in up to 25% in people with T1D and up to 10% in people with T2D. IAH and HAAF increase the risk of severe hypoglycemia 6-fold and 25-fold, respectively. To reduce this risk for severe hypoglycemia, multiple different therapeutic approaches are being explored that could improve awareness of hypoglycemia. Current therapies to improve awareness of hypoglycemia include patient education and psychoeducation, the use of novel glycemic control technology, pancreas/islet transplantation, and drug therapy. This review examines both existing therapies and potential therapies that are in pre-clinical testing. Novel treatments that improve awareness of hypoglycemia, via improving the counterregulatory hormone responses or improving hypoglycemic symptom recognition, would also shed light on the possible neurological mechanisms that lead to the development of IAH. To reduce the risk of severe hypoglycemia in people with diabetes, elucidating the mechanism behind IAH, as well as developing targeted therapies is currently an unmet need for those that suffer from IAH.
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Affiliation(s)
- Erica L. Macon
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Micah H. Devore
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Yu Kuei Lin
- Division of Metabolism, Endocrinology and Diabetes, Department of Internal Medicine, University of Michigan Medical School, Ann Arbor, MI, United States
| | - Megan B. Music
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Mason Wooten
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Colleen A. McMullen
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Andrea M. Woodcox
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Ashlee R. Marksbury
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Zachary Beckner
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Bansi V. Patel
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Lily A. Schoeder
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Ashley N. Iles
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
| | - Simon J. Fisher
- Division of Endocrinology, Diabetes and Metabolism, Department of Internal Medicine, College of Medicine, University of Kentucky, Lexington, KY, United States
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Huang C, Huang L, Huang Q, Lin L, Wang L, Wu Y, Wu K, Gao R, Liu X, Liu X, Qi L, Liu L. Mitophagy disorder mediates cardiac deterioration induced by severe hypoglycemia in diabetic mice. Mol Cell Endocrinol 2023; 575:111994. [PMID: 37330037 DOI: 10.1016/j.mce.2023.111994] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/15/2023] [Revised: 06/07/2023] [Accepted: 06/15/2023] [Indexed: 06/19/2023]
Abstract
Severe hypoglycemia is closely related to adverse cardiovascular outcomes in patients with diabetes; however, the specific mechanism remains unclear. We previously found that severe hypoglycemia aggravated myocardial injury and cardiac dysfunction in diabetic mice, and that the mechanism of damage was related to mitochondrial oxidative stress and dysfunction. Based on the key regulatory role of mitophagy in mitochondrial quality control, this study aimed to further explore whether the myocardial damage caused by severe hypoglycemia is related to insufficient mitophagy and to clarify their underlying regulatory relationship. After severe hypoglycemia, mitochondrial reactive oxygen species increased, mitochondrial membrane potential and ATP content decreased, and pathological mitochondrial damage was aggravated in the myocardium of diabetic mice. This was accompanied by decreased mitochondrial biosynthesis, increased fusion, and downregulated PTEN-induced kinase 1 (PINK1)/Parkin-dependent mitophagy. Treating diabetic mice with the mitophagy activator and polyphenol metabolite urolithin A activated PINK1/Parkin-dependent mitophagy, reduced myocardial oxidative stress and mitochondrial damage associated with severe hypoglycemia, improved mitochondrial function, alleviated myocardial damage, and ultimately improved cardiac function. Thus, we provide insight into the prevention and treatment of diabetic myocardial injury caused by hypoglycemia to reduce adverse cardiovascular outcomes in patients with diabetes.
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Affiliation(s)
- Cuihua Huang
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350000, China
| | - Lishan Huang
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350000, China
| | - Qintao Huang
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350000, China
| | - Lu Lin
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350000, China
| | - Lijing Wang
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350000, China
| | - Yubin Wu
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350000, China
| | - Kejun Wu
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350000, China
| | - Ruonan Gao
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350000, China
| | - Xiaoying Liu
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350000, China
| | - XiaoHong Liu
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350000, China
| | - Liqin Qi
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350000, China.
| | - Libin Liu
- Department of Endocrinology, Fujian Medical University Union Hospital, Fuzhou, 350000, China.
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Seaquist ER, Teff K, Heller SR. Impaired Awareness of Hypoglycemia in Type 1 Diabetes: A Report of An NIDDK Workshop in October 2021. Diabetes Care 2022; 45:2799-2805. [PMID: 36455118 PMCID: PMC9763030 DOI: 10.2337/dc22-1242] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2022] [Accepted: 09/14/2022] [Indexed: 12/03/2022]
Abstract
Hypoglycemia remains a limiting factor in the optimal treatment of type 1 diabetes. Repeated episodes of hypoglycemia result in impaired awareness of subsequent hypoglycemic events, inducing a vicious feed-forward cycle and increasing the risk of morbidity and mortality. Why this occurs and how to manage the problem in clinical practice remain uncertain. To address the obstacles and barriers that have hindered progress in this clinically important area, the National Institute of Diabetes and Digestive and Kidney Diseases convened a workshop on 14-15 October 2021. This perspective offers a summary of this outstanding meeting, which brought clinical and basic scientists from the fields of diabetes, neuroscience, psychology, psychiatry, and imaging together, on how to best advance the field of impaired awareness of hypoglycemia and hypoglycemia in general in patients with diabetes.
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Affiliation(s)
| | - Karen Teff
- National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD
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Bisgaard Bengtsen M, Møller N. Review: experimentally induced hypoglycemia-associated autonomic failure in humans: determinants, designs and drawbacks. J Endocr Soc 2022; 6:bvac123. [PMID: 36042977 PMCID: PMC9419494 DOI: 10.1210/jendso/bvac123] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2022] [Indexed: 11/19/2022] Open
Abstract
Context Iatrogenic hypoglycemia remains one of the leading hindrances of optimal glycemic management in insulin-treated diabetes. Recurring hypoglycemia leads to a condition of hypoglycemia-associated autonomic failure (HAAF). HAAF refers to a combination of (i) impaired hormonal counterregulatory responses and (ii) hypoglycemia unawareness to subsequent hypoglycemia, substantially increasing the risk of severe hypoglycemia. Several studies since the 1990s have experimentally induced HAAF, yielding variable results. Objective The aim of this review was to assess the varying designs, clinical outcomes, potential assets, and drawbacks related to these studies. Method A systemic literature search was conducted on PubMed and Embase in winter 2021 to include all human studies attempting to experimentally induce HAAF. In different combinations, the search terms used were “hypoglycemia-associated autonomic failure,” “HAAF,” “hypoglycemia,” “recurring,” “recurrent,” “repeated,” “consecutive,” and “unawareness,” yielding 1565 publications. Inclusion criteria were studies that had aimed at experimentally inducing HAAF and measuring outcomes of hormonal counterregulation and awareness of hypoglycemia. Results The literature search yielded 27 eligible publications, of which 20 were successful in inducing HAAF while statistical significantly impairing both hormonal counterregulation and impairing awareness of hypoglycemia to subsequent hypoglycemia. Several factors were of significance as regards inducing HAAF: Foremost, the duration of antecedent hypoglycemia should be at least 90 minutes and blood glucose should be maintained below 3.4 mmol/L. Other important factors to consider are the type of participants, insulin dosage, and the risk of unintended hypoglycemia prior to the study. Conclusion Here we have outlined the most important factors to take into consideration when designing a study aimed at inducing HAAF, including to take into consideration other disease states susceptible to hypoglycemia, thus hopefully clarifying the field and allowing qualified studies in the future.
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Affiliation(s)
| | - Niels Møller
- Department of Endocrinology and Internal Medicine , Aarhus University Hospital, Denmark
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Zhang Y, Öz G, Moheet A, Kumar A, Alvear A, Mangia S, Eberly L, Seaquist ER. Heterogeneity in epinephrine response to experimental hypoglycemia in type 1 diabetes and controls. J Endocr Soc 2022; 6:bvac046. [PMID: 35475026 PMCID: PMC9032637 DOI: 10.1210/jendso/bvac046] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2022] [Indexed: 11/29/2022] Open
Abstract
Context The epinephrine response (Epi) to a first episode of hypoglycemia (HG) has been proposed to be predictive of Epi in subsequent HG and to provide insight into the risk for developing HG-associated autonomic failure (HAAF) in healthy controls (HCs). Objective To determine if Epi and symptom response (SR) to the first episode of HG predicts who will develop HAAF after exposure to recurrent HG in volunteers with type 1 diabetes (T1D) and in HCs. Design Review of data collected between 2013 and 2019. Setting Academic clinical research unit. Patients or Participants Volunteers with T1D and HCs. Interventions Subjects participated in a preinduction protocol where they were exposed to three 2-hour episodes of clamped HG over 2 days. Data collected during clamp 1 were compared with data collected during clamp 3. Main outcome measure Difference in Epi and SR. Results Using the standard definition of HAAF in which HG-induced Epi during clamp 3 is at least 20% lower than during clamp 1, 21/28 HCs and 13/19 volunteers with T1D developed HAAF. Epi during clamp 1 was significantly higher in those subjects who developed HAAF than in those who did not in both groups (P = 0.02). If HAAF is defined as achieving a 20% reduction in HG-induced SR measured during clamp 3 compared with clamp 1, 10/27 HCs and 10/19 volunteers with T1D developed SR-based HAAF. Conclusion There was heterogeneity in the response to the preinduction protocol. Epi during clamp 1 was higher than in clamp 3 in HCs and in those with T1D who developed HAAF.
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Affiliation(s)
- Yuan Zhang
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, MN, USA
| | - Gülin Öz
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, USA
| | - Amir Moheet
- Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Anjali Kumar
- Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Alison Alvear
- Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
| | - Silvia Mangia
- Center for Magnetic Resonance Research, Department of Radiology, University of Minnesota, Minneapolis, MN, USA
| | - Lynn Eberly
- Division of Biostatistics, School of Public Health, University of Minnesota, Minneapolis, MN, USA
| | - Elizabeth R Seaquist
- Division of Endocrinology and Diabetes, Department of Medicine, University of Minnesota, Minneapolis, MN, USA
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Farhat R, de Santana‐Van Vliet E, Su G, Neely L, Benally T, Chan O. Carvedilol prevents impairment of the counterregulatory response in recurrently hypoglycaemic diabetic rats. Endocrinol Diabetes Metab 2021; 4:e00226. [PMID: 33855225 PMCID: PMC8029566 DOI: 10.1002/edm2.226] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2020] [Revised: 12/22/2020] [Accepted: 12/26/2020] [Indexed: 02/05/2023] Open
Abstract
Aim It has been suggested that repeated activation of the adrenergic system during antecedent episodes of hypoglycaemia contributes to the development of counterregulatory failure. We previously reported that treatment with carvedilol, a non-specific β-blocker, prevented the development of counterregulatory failure and improved hypoglycaemia awareness in recurrently hypoglycaemic non-diabetic rats. The current study investigated whether carvedilol has similar benefits in diabetic rats. Methods Recurrently hypoglycaemic streptozotocin-diabetic rats (STZ+RH) were treated with carvedilol for one week prior to undergoing a hypoglycaemic clamp. Hypoglycaemia awareness was evaluated in streptozotocin-diabetic rats made hypoglycaemia unaware using repeated injections of 2-deoxyglucose. Results Compared to hypoglycaemia-naïve STZ-diabetic controls, exogenous glucose requirements were more than doubled in the STZ+RH animals and this was associated with a 49% reduction in the epinephrine response to hypoglycaemia. Treating STZ+RH animals with carvedilol improved the epinephrine response to hypoglycaemia. Of note, neither recurrent hypoglycaemia nor carvedilol treatment affected the glucagon response in diabetic animals. Additionally, carvedilol treatment improved the feeding response to insulin-induced hypoglycaemia in diabetic animals made 'hypoglycaemia unaware' using repeated injections of 2-deoxyglucose, suggesting the treatment improved awareness of hypoglycaemia as well. Conclusion Our data suggest that carvedilol may be useful in preventing impairments of the sympathoadrenal response and the development of hypoglycaemia unawareness during recurring episodes of hypoglycaemia in diabetic animals.
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Affiliation(s)
- Rawad Farhat
- Department of Internal MedicineDivision of Endocrinology, Metabolism and DiabetesUniversity of UtahSalt Lake CityUTUSA
| | - Eliane de Santana‐Van Vliet
- Department of Internal MedicineDivision of Endocrinology, Metabolism and DiabetesUniversity of UtahSalt Lake CityUTUSA
| | - Gong Su
- Department of Cardiovascular MedicineShanghai Wusong Central HospitalShanghaiChina
| | - Levi Neely
- Department of BiologyUtah Valley UniversityOremUTUSA
| | - Thea Benally
- Department of Health, Exercise and Sports SciencesUniversity of New MexicoAlbuquerqueNMUSA
| | - Owen Chan
- Department of Internal MedicineDivision of Endocrinology, Metabolism and DiabetesUniversity of UtahSalt Lake CityUTUSA
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Sejling AS, Wang P, Zhu W, Farhat R, Knight N, Appadurai D, Chan O. Repeated Activation of Noradrenergic Receptors in the Ventromedial Hypothalamus Suppresses the Response to Hypoglycemia. Endocrinology 2021; 162:6052997. [PMID: 33367607 PMCID: PMC7814298 DOI: 10.1210/endocr/bqaa241] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/07/2020] [Indexed: 11/19/2022]
Abstract
Activation of the adrenergic system in response to hypoglycemia is important for proper recovery from low glucose levels. However, it has been suggested that repeated adrenergic stimulation may also contribute to counterregulatory failure, but the underlying mechanisms are not known. The aim of this study was to establish whether repeated activation of noradrenergic receptors in the ventromedial hypothalamus (VMH) contributes to blunting of the counterregulatory response by enhancing local lactate production. The VMH of nondiabetic rats were infused with either artificial extracellular fluid, norepinephrine (NE), or salbutamol for 3 hours/day for 3 consecutive days before they underwent a hypoglycemic clamp with microdialysis to monitor changes in VMH lactate levels. Repeated exposure to NE or salbutamol suppressed both the glucagon and epinephrine responses to hypoglycemia compared to controls. Furthermore, antecedent NE and salbutamol treatments raised extracellular lactate levels in the VMH. To determine whether the elevated lactate levels were responsible for impairing the hormone response, we pharmacologically inhibited neuronal lactate transport in a subgroup of NE-treated rats during the clamp. Blocking neuronal lactate utilization improved the counterregulatory hormone responses in NE-treated animals, suggesting that repeated activation of VMH β2-adrenergic receptors increases local lactate levels which in turn, suppresses the counterregulatory hormone response to hypoglycemia.
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Affiliation(s)
- Anne-Sophie Sejling
- Department of Endocrinology and Nephrology, Nordsjællands Hospital, Dyrehavevej, Denmark
- Current Affiliation: A.S. is currently with Novo Nordisk A/S
| | - Peili Wang
- Department of Internal Medicine-Section of Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Wanling Zhu
- Department of Internal Medicine-Section of Endocrinology, Yale School of Medicine, New Haven, CT, USA
| | - Rawad Farhat
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
| | - Nicholas Knight
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
| | - Daniel Appadurai
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
| | - Owen Chan
- Department of Internal Medicine—Division of Endocrinology, Metabolism and Diabetes, University of Utah, Salt Lake City, UT, USA
- Correspondence: Dr. Owen Chan, PhD, University of Utah, Department of Internal Medicine, Division of Endocrinology, Metabolism and Diabetes, 15 North 2030 East, Rm 2420B, Salt Lake City, UT 84112, USA.
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