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Heni M. The insulin resistant brain: impact on whole-body metabolism and body fat distribution. Diabetologia 2024; 67:1181-1191. [PMID: 38363340 PMCID: PMC11153284 DOI: 10.1007/s00125-024-06104-9] [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: 07/21/2023] [Accepted: 12/19/2023] [Indexed: 02/17/2024]
Abstract
Insulin exerts its actions not only on peripheral organs but is also transported into the brain where it performs distinct functions in various brain regions. This review highlights recent advancements in our understanding of insulin's actions within the brain, with a specific emphasis on investigations in humans. It summarises current knowledge on the transport of insulin into the brain. Subsequently, it showcases robust evidence demonstrating the existence and physiological consequences of brain insulin action, while also introducing the presence of brain insulin resistance in humans. This pathophysiological condition goes along with an impaired acute modulation of peripheral metabolism in response to brain insulin action, particularly in the postprandial state. Furthermore, brain insulin resistance has been associated with long-term adiposity and an unfavourable adipose tissue distribution, thus implicating it in the pathogenesis of subgroups of obesity and (pre)diabetes that are characterised by distinct patterns of body fat distribution. Encouragingly, emerging evidence suggests that brain insulin resistance could represent a treatable entity, thereby opening up novel therapeutic avenues to improve systemic metabolism and enhance brain functions, including cognition. The review closes with an outlook towards prospective research directions aimed at further elucidating the clinical implications of brain insulin resistance. It emphasises the critical need to establish feasible diagnostic measures and effective therapeutic interventions.
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Affiliation(s)
- Martin Heni
- Division of Endocrinology and Diabetology, Department of Internal Medicine 1, University Hospital Ulm, Ulm, Germany.
- Department for Diagnostic Laboratory Medicine, Institute for Clinical Chemistry and Pathobiochemistry, University Hospital of Tübingen, Tübingen, Germany.
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2
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Strong TV, Miller JL, McCandless SE, Gevers E, Yanovski JA, Matesevac L, Bohonowych J, Ballal S, Yen K, Hirano P, Cowen NM, Bhatnagar A. Behavioral changes in patients with Prader-Willi syndrome receiving diazoxide choline extended-release tablets compared to the PATH for PWS natural history study. J Neurodev Disord 2024; 16:22. [PMID: 38671361 PMCID: PMC11046911 DOI: 10.1186/s11689-024-09536-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: 09/30/2023] [Accepted: 04/10/2024] [Indexed: 04/28/2024] Open
Abstract
BACKGROUND Prader-Willi syndrome (PWS) is a rare neurobehavioral-metabolic disease caused by the lack of paternally expressed genes in the chromosome 15q11-q13 region, characterized by hypotonia, neurocognitive problems, behavioral difficulties, endocrinopathies, and hyperphagia resulting in severe obesity if energy intake is not controlled. Diazoxide choline extended-release (DCCR) tablets have previously been evaluated for their effects on hyperphagia and other behavioral complications of people with PWS in a Phase 3 placebo-controlled study of participants with PWS, age 4 and older with hyperphagia (C601) and in an open label extension study, C602. METHODS To better understand the longer-term impact of DCCR, a cohort from PATH for PWS, a natural history study that enrolled participants with PWS age 5 and older, who met the C601 age, weight and baseline hyperphagia inclusion criteria and had 2 hyperphagia assessments ≥ 6 months apart, were compared to the C601/C602 cohort. Hyperphagia was measured using the Hyperphagia Questionnaire for Clinical Trials (HQ-CT, range 0-36). The primary analysis used observed values with no explicit imputation of missing data. A sensitivity analysis was conducted in which all missing HQ-CT assessments in the C601/C602 cohort were assigned the highest possible value (36), representing the worst-case scenario. Other behavioral changes were assessed using the Prader-Willi Syndrome Profile questionnaire (PWSP). RESULTS Relative to the PATH for PWS natural history study cohort, the DCCR-treated C601/C602 cohort showed significant improvements in HQ-CT score at 26 weeks (LSmean [SE] -8.3 [0.75] vs. -2.5 [0.43], p < 0.001) and 52 weeks (LSmean [SE] -9.2 [0.77] vs. -3.4 [0.47], p < 0.001). The comparison between the cohorts remained significant in the worst-case imputation sensitivity analysis. There were also significant improvements in all domains of the PWSP at 26 weeks (all p < 0.001) and 52 weeks (all p ≤ 0.003) for C601/C602 participants compared to the PATH for PWS participants. CONCLUSION Long-term administration of DCCR to people with PWS resulted in changes in hyperphagia and other behavioral complications of PWS that are distinct from the natural history of the syndrome as exemplified by the cohort from PATH for PWS. The combined effects of administration of DCCR should reduce the burden of the syndrome on the patient, caregivers and their families, and thereby may benefit people with PWS and their families. TRIAL REGISTRATION Clinical study C601 was originally registered on ClinicalTrials.gov on February 22, 2018 (NCT03440814). Clinical study C602 was originally registered on ClinicalTrials.gov on October 22, 2018 (NCT03714373). PATH for PWS was originally registered on ClinicalTrials.gov on October 24, 2018 (NCT03718416).
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Affiliation(s)
| | - Jennifer L Miller
- University of Florida College of Medicine, Gainesville, FL, 32610, USA
| | - Shawn E McCandless
- University of Colorado School of Medicine and Children's Hospital Colorado, Aurora, CO, 80045, USA
| | - Evelien Gevers
- Queen Mary University of London and Barts Health NHS Trust - Royal London Children's Hospital, London, E1 1FR, UK
| | - Jack A Yanovski
- US Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institute of Health, Bethesda, MD, 20847, USA
| | - Lisa Matesevac
- Foundation for Prader-Willi Research, Covina, CA, 91723, USA
| | | | | | - Kristen Yen
- Soleno Therapeutics, Redwood City, CA, 94065, USA
| | | | - Neil M Cowen
- Soleno Therapeutics, Redwood City, CA, 94065, USA
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3
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Miller JL, Gevers E, Bridges N, Yanovski JA, Salehi P, Obrynba KS, Felner EI, Bird LM, Shoemaker AH, Angulo M, Butler MG, Stevenson D, Goldstone AP, Wilding J, Lah M, Shaikh MG, Littlejohn E, Abuzzahab MJ, Fleischman A, Hirano P, Yen K, Cowen NM, Bhatnagar A. Diazoxide choline extended-release tablet in people with Prader-Willi syndrome: results from long-term open-label study. Obesity (Silver Spring) 2024; 32:252-261. [PMID: 37919617 DOI: 10.1002/oby.23928] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2023] [Revised: 09/05/2023] [Accepted: 09/06/2023] [Indexed: 11/04/2023]
Abstract
OBJECTIVE This study assessed the effect of 1-year administration of diazoxide choline extended-release tablet (DCCR) on hyperphagia and other complications of Prader-Willi syndrome (PWS). METHODS The authors studied 125 participants with PWS, age ≥ 4 years, who were enrolled in the DESTINY PWS Phase 3 study and who received DCCR for up to 52 weeks in DESTINY PWS and/or its open-label extension. The primary efficacy endpoint was Hyperphagia Questionnaire for Clinical Trials (HQ-CT) score. Other endpoints included behavioral assessments, body composition, hormonal measures, and safety. RESULTS DCCR administration resulted in significant improvements in HQ-CT (mean [SE] -9.9 [0.77], p < 0.0001) and greater improvements in those with more severe baseline hyperphagia (HQ-CT > 22). Improvements were seen in aggression, anxiety, and compulsivity (all p < 0.0001). There were reductions in leptin, insulin, and insulin resistance, as well as a significant increase in adiponectin (all p < 0.004). Lean body mass was increased (p < 0.0001). Disease severity was reduced as assessed by clinician and caregiver (both p < 0.0001). Common treatment-emergent adverse events included hypertrichosis, peripheral edema, and hyperglycemia. Adverse events infrequently resulted in discontinuation (7.2%). CONCLUSIONS DCCR administration to people with PWS was well tolerated and associated with broad-ranging improvements in the syndrome. Sustained administration of DCCR has the potential to reduce disease severity and the burden of care for families.
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Affiliation(s)
- Jennifer L Miller
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, Florida, USA
| | - Evelien Gevers
- Queen Mary University of London, Barts Health NHS Trust-Royal London Children's Hospital, London, UK
| | | | - Jack A Yanovski
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland, USA
| | - Parisa Salehi
- Seattle Children's Hospital, Seattle, Washington, USA
| | | | - Eric I Felner
- Emory University School of Medicine, Atlanta, Georgia, USA
| | - Lynne M Bird
- University of California, San Diego/Rady Children's Hospital, San Diego, California, USA
| | | | - Moris Angulo
- New York University Langone Health, Mineola, New York, USA
| | - Merlin G Butler
- University of Kansas Medical Center, Kansas City, Kansas, USA
| | | | - Anthony P Goldstone
- Department of Endocrinology, Imperial College Healthcare NHS Trust, Hammersmith Hospital, London, UK
| | - John Wilding
- University of Liverpool, Clinical Sciences Centre, Aintree University Hospital, Liverpool, UK
| | - Melissa Lah
- Indiana University School of Medicine, Indianapolis, Indiana, USA
| | - M Guftar Shaikh
- Royal Hospital for Children, University of Glasgow, Glasgow, UK
| | | | | | | | | | - Kristen Yen
- Soleno Therapeutics, Redwood City, California, USA
| | - Neil M Cowen
- Soleno Therapeutics, Redwood City, California, USA
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Haspula D, Cui Z. Neurochemical Basis of Inter-Organ Crosstalk in Health and Obesity: Focus on the Hypothalamus and the Brainstem. Cells 2023; 12:1801. [PMID: 37443835 PMCID: PMC10341274 DOI: 10.3390/cells12131801] [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: 05/15/2023] [Revised: 06/23/2023] [Accepted: 07/03/2023] [Indexed: 07/15/2023] Open
Abstract
Precise neural regulation is required for maintenance of energy homeostasis. Essential to this are the hypothalamic and brainstem nuclei which are located adjacent and supra-adjacent to the circumventricular organs. They comprise multiple distinct neuronal populations which receive inputs not only from other brain regions, but also from circulating signals such as hormones, nutrients, metabolites and postprandial signals. Hence, they are ideally placed to exert a multi-tier control over metabolism. The neuronal sub-populations present in these key metabolically relevant nuclei regulate various facets of energy balance which includes appetite/satiety control, substrate utilization by peripheral organs and glucose homeostasis. In situations of heightened energy demand or excess, they maintain energy homeostasis by restoring the balance between energy intake and expenditure. While research on the metabolic role of the central nervous system has progressed rapidly, the neural circuitry and molecular mechanisms involved in regulating distinct metabolic functions have only gained traction in the last few decades. The focus of this review is to provide an updated summary of the mechanisms by which the various neuronal subpopulations, mainly located in the hypothalamus and the brainstem, regulate key metabolic functions.
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Affiliation(s)
- Dhanush Haspula
- Molecular Signaling Section, Laboratory of Bioorganic Chemistry, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA
| | - Zhenzhong Cui
- Mouse Metabolism Core, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD 20892, USA;
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Cook JR, Hawkins MA, Pajvani UB. Liver insulinization as a driver of triglyceride dysmetabolism. Nat Metab 2023; 5:1101-1110. [PMID: 37460842 DOI: 10.1038/s42255-023-00843-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/10/2023] [Accepted: 06/13/2023] [Indexed: 07/26/2023]
Abstract
Metabolic dysfunction-associated fatty liver disease (MAFLD) is an increasingly prevalent fellow traveller with the insulin resistance that underlies type 2 diabetes mellitus. However, the mechanistic connection between MAFLD and impaired insulin action remains unclear. In this Perspective, we review data from humans to elucidate insulin's aetiological role in MAFLD. We focus particularly on the relative preservation of insulin's stimulation of triglyceride (TG) biosynthesis despite its waning ability to curb hepatic glucose production (HGP). To explain this apparent 'selective insulin resistance', we propose that hepatocellular processes that lead to TG accumulation require less insulin signal transduction, or 'insulinization,' than do those that regulate HGP. As such, mounting hyperinsulinaemia that barely compensates for aberrant HGP in insulin-resistant states more than suffices to maintain hepatic TG biosynthesis. Thus, even modestly elevated or context-inappropriate insulin levels, when sustained day and night within a heavily pro-lipogenic metabolic milieu, may translate into substantial cumulative TG biosynthesis in the insulin-resistant state.
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Affiliation(s)
- Joshua R Cook
- Naomi Berrie Diabetes Center, Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, Columbia University College of Physicians & Surgeons, New York City, NY, USA.
| | - Meredith A Hawkins
- Diabetes Research and Training Center, Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, New York City, NY, USA
| | - Utpal B Pajvani
- Naomi Berrie Diabetes Center, Division of Endocrinology, Diabetes & Metabolism, Department of Medicine, Columbia University College of Physicians & Surgeons, New York City, NY, USA
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6
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Miller JL, Gevers E, Bridges N, Yanovski JA, Salehi P, Obrynba KS, Felner EI, Bird LM, Shoemaker AH, Angulo M, Butler MG, Stevenson D, Abuzzahab J, Barrett T, Lah M, Littlejohn E, Mathew V, Cowen NM, Bhatnagar A. Diazoxide Choline Extended-Release Tablet in People With Prader-Willi Syndrome: A Double-Blind, Placebo-Controlled Trial. J Clin Endocrinol Metab 2023; 108:1676-1685. [PMID: 36639249 PMCID: PMC10271219 DOI: 10.1210/clinem/dgad014] [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: 09/06/2022] [Revised: 01/03/2023] [Accepted: 01/09/2023] [Indexed: 01/15/2023]
Abstract
CONTEXT Prader-Willi syndrome (PWS) is a rare neurobehavioral-metabolic disease caused by the lack of paternally expressed genes in the chromosome 15q11-q13 region, characterized by hypotonia, neurocognitive problems, behavioral difficulties, endocrinopathies, and hyperphagia resulting in severe obesity if not controlled. OBJECTIVE The primary end point was change from baseline in hyperphagia using the Hyperphagia Questionnaire for Clinical Trials (HQ-CT). Other end points included Global Impression Scores, and changes in body composition, behaviors, and hormones. METHODS In DESTINY PWS, a 13-week, randomized, double-blind, placebo-controlled, phase 3 trial, 127 participants with PWS aged 4 years and older with hyperphagia were randomly assigned 2:1 to diazoxide choline extended-release tablet (DCCR) or placebo. RESULTS DCCR did not significantly improve hyperphagia (HQ-CT least-square mean (LSmean) [SE] -5.94 [0.879] vs -4.27 [1.145]; P = .198), but did so in participants with severe hyperphagia (LSmean [SE] -9.67 [1.429] vs -4.26 [1.896]; P = .012). Two of 3 secondary end points were improved (Clinical Global Impression of Improvement [CGI-I]; P = .029; fat mass; P = .023). In an analysis of results generated pre-COVID, the primary (HQ-CT; P = .037) and secondary end points were all improved (CGI-I; P = .015; Caregiver Global Impression of Change; P = .031; fat mass; P = .003). In general, DCCR was well tolerated with 83.3% in the DCCR group experiencing a treatment-emergent adverse event and 73.8% in the placebo group (not significant). CONCLUSION DCCR did not significantly improve hyperphagia in the primary analysis but did in participants with severe baseline hyperphagia and in the pre-COVID analysis. DCCR treatment was associated with significant improvements in body composition and clinician-reported outcomes.
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Affiliation(s)
- Jennifer L Miller
- Department of Pediatric Endocrinology, University of Florida College of Medicine, Gainesville, Florida 32608, USA
| | - Evelien Gevers
- Queen Mary University London, London E1 4NS, UK; Barts Health NHS Trust-Royal London Children's Hospital, London E1 1FR, UK
| | | | - Jack A Yanovski
- US Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, Maryland 20892, USA
| | - Parisa Salehi
- Endocrinology, Seattle Children's Hospital, Seattle, Washington 98105, USA
| | - Kathryn S Obrynba
- Endocrinology, Nationwide Children's Hospital, Columbus, Ohio 43205, USA
| | - Eric I Felner
- Department of Pediatrics, Emory University School of Medicine, Atlanta, Georgia 30322, USA
| | - Lynne M Bird
- University of California, San Diego/Rady's Children's Hospital, San Diego, California 92123, USA
| | | | - Moris Angulo
- NYU Langone Health, Mineola, New York 11501, USA
| | - Merlin G Butler
- University of Kansas Medical Center, Kansas City, Kansas 66160, USA
| | | | | | - Timothy Barrett
- Birmingham Women's and Children's Hospital, Birmingham B15 2TG, UK
| | - Melissa Lah
- Indiana University School of Medicine, Indianapolis, Indiana 46202, USA
| | | | - Verghese Mathew
- Hull and East Yorkshire Hospitals NHS Trust, Hull HU3 2JZ, UK
| | - Neil M Cowen
- Soleno Therapeutics, Redwood City, California 94065, USA
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7
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Clinical Trials in Prader-Willi Syndrome: A Review. Int J Mol Sci 2023; 24:ijms24032150. [PMID: 36768472 PMCID: PMC9916985 DOI: 10.3390/ijms24032150] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2022] [Revised: 12/28/2022] [Accepted: 01/16/2023] [Indexed: 01/25/2023] Open
Abstract
Prader-Willi syndrome (PWS) is a complex, genetic, neurodevelopmental disorder. PWS has three molecular genetic classes. The most common defect is due to a paternal 15q11-q13 deletion observed in about 60% of individuals. This is followed by maternal disomy 15 (both 15 s from the mother), found in approximately 35% of cases. the remaining individuals have a defect of the imprinting center that controls the activity of imprinted genes on chromosome 15. Mild cognitive impairment and behavior problems in PWS include self-injury, anxiety, compulsions, and outbursts in childhood, impacted by genetic subtypes. Food seeking and hyperphagia can lead to morbid obesity and contribute to diabetes and cardiovascular or orthopedic problems. The control of hyperphagia and improving food-related behaviors are the most important unmet needs in PWS and could be addressed with the development of a new therapeutic agent, as currently no approved therapeutics exist for PWS treatment. The status of clinical trials with existing results for the management of obesity and hyperphagia in PWS will be discussed in this review, including treatments such as beloranib, setmelanotide, a diazoxide choline controlled-release tablet (DCCR), an unacylated ghrelin analogue, oxytocin and related compounds, glucagon-like peptide 1 receptor agonists, surgical intervention, and transcranial direct-current stimulation.
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8
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Malin SK, Stewart NR, Ude AA, Alderman BL. Brain insulin resistance and cognitive function: influence of exercise. J Appl Physiol (1985) 2022; 133:1368-1380. [PMID: 36269295 PMCID: PMC9744647 DOI: 10.1152/japplphysiol.00375.2022] [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: 07/01/2022] [Revised: 10/12/2022] [Accepted: 10/12/2022] [Indexed: 12/15/2022] Open
Abstract
Exercise has systemic health benefits in people, in part, through improving whole body insulin sensitivity. The brain is an insulin-sensitive organ that is often underdiscussed relative to skeletal muscle, liver, and adipose tissue. Although brain insulin action may have only subtle impacts on peripheral regulation of systemic glucose homeostasis, it is important for weight regulation as well as mental health. In fact, brain insulin signaling is also involved in processes that support healthy cognition. Furthermore, brain insulin resistance has been associated with age-related declines in memory and executive function as well as Alzheimer's disease pathology. Herein, we provide an overview of brain insulin sensitivity in relation to cognitive function from animal and human studies, with particular emphasis placed on the impact exercise may have on brain insulin sensitivity. Mechanisms discussed include mitochondrial function, brain growth factors, and neurogenesis, which collectively help combat obesity-related metabolic disease and Alzheimer's dementia.
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Affiliation(s)
- Steven K Malin
- Department of Kinesiology & Health, Rutgers University, New Brunswick, New Jersey
- Division of Endocrinology, Metabolism & Nutrition, Rutgers University, New Brunswick, New Jersey
- New Jersey Institute for Food, Nutrition and Health, Rutgers University, New Brunswick, New Jersey
- Institute of Translational Medicine and Science, Rutgers University, New Brunswick, New Jersey
| | - Nathan R Stewart
- Department of Kinesiology & Health, Rutgers University, New Brunswick, New Jersey
| | - Andrew A Ude
- Department of Kinesiology & Health, Rutgers University, New Brunswick, New Jersey
| | - Brandon L Alderman
- Department of Kinesiology & Health, Rutgers University, New Brunswick, New Jersey
- Center of Alcohol and Substance Use Studies, Rutgers University, New Brunswick, New Jersey
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9
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Eerola K, Longo F, Reinbothe TM, Richard JE, Shevchouk OT, López-Ferreras L, Mishra D, Asker M, Tolö J, Miranda C, Musovic S, Olofsson CS, Rorsman P, Skibicka KP. Hindbrain insulin controls feeding behavior. Mol Metab 2022; 66:101614. [PMID: 36244663 PMCID: PMC9637798 DOI: 10.1016/j.molmet.2022.101614] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/02/2022] [Revised: 10/10/2022] [Accepted: 10/11/2022] [Indexed: 11/08/2022] Open
Abstract
OBJECTIVE Pancreatic insulin was discovered a century ago, and this discovery led to the first lifesaving treatment for diabetes. While still controversial, nearly one hundred published reports suggest that insulin is also produced in the brain, with most focusing on hypothalamic or cortical insulin-producing cells. However, specific function for insulin produced within the brain remains poorly understood. Here we identify insulin expression in the hindbrain's dorsal vagal complex (DVC), and determine the role of this source of insulin in feeding and metabolism, as well as its response to diet-induced obesity in mice. METHODS To determine the contribution of Ins2-producing neurons to feeding behavior in mice, we used the cross of transgenic RipHER-cre mouse and channelrhodopsin-2 expressing animals, which allowed us to optogenetically stimulate neurons expressing Ins2 in vivo. To confirm the presence of insulin expression in Rip-labeled DVC cells, in situ hybridization was used. To ascertain the specific role of insulin in effects discovered via optogenetic stimulation a selective, CNS applied, insulin receptor antagonist was used. To understand the physiological contribution of insulin made in the hindbrain a virogenetic knockdown strategy was used. RESULTS Insulin gene expression and presence of insulin-promoter driven fluorescence in rat insulin promoter (Rip)-transgenic mice were detected in the hypothalamus, but also in the DVC. Insulin mRNA was present in nearly all fluorescently labeled cells in DVC. Diet-induced obesity in mice altered brain insulin gene expression, in a neuroanatomically divergent manner; while in the hypothalamus the expected obesity-induced reduction was found, in the DVC diet-induced obesity resulted in increased expression of the insulin gene. This led us to hypothesize a potentially divergent energy balance role of insulin in these two brain areas. To determine the acute impact of activating insulin-producing neurons in the DVC, optic stimulation of light-sensitive channelrhodopsin 2 in Rip-transgenic mice was utilized. Optogenetic photoactivation induced hyperphagia after acute activation of the DVC insulin neurons. This hyperphagia was blocked by central application of the insulin receptor antagonist S961, suggesting the feeding response was driven by insulin. To determine whether DVC insulin has a necessary contribution to feeding and metabolism, virogenetic insulin gene knockdown (KD) strategy, which allows for site-specific reduction of insulin gene expression in adult mice, was used. While chow-fed mice failed to reveal any changes of feeding or thermogenesis in response to the KD, mice challenged with a high-fat diet consumed less food. No changes in body weight were identified, possibly resulting from compensatory reduction in thermogenesis. CONCLUSIONS Together, our data suggest an important role for hindbrain insulin and insulin-producing cells in energy homeostasis.
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Affiliation(s)
- Kim Eerola
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden,Unit of Integrative Physiology and Pharmacology, Institute of Biomedicine, University of Turku, Finland
| | - Francesco Longo
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | | | | | | | | | - Devesh Mishra
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | - Mohammed Asker
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | - Johan Tolö
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | - Caroline Miranda
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | - Saliha Musovic
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden
| | | | - Patrik Rorsman
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden,Oxford Centre for Diabetes, Endocrinology and Metabolism, University of Oxford, Churchill Hospital, Oxford, UK
| | - Karolina P. Skibicka
- Institute for Neuroscience and Physiology, University of Gothenburg, Sweden,Wallenberg Centre for Molecular and Translational Medicine, University of Gothenburg, Sweden,Department of Nutritional Sciences and The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA, USA,Corresponding author. Department of Physiology, Institute of Neuroscience and Physiology, The Sahlgrenska Academy at the University of Gothenburg, Medicinaregatan 11, PO Box 434, SE-405 30, Gothenburg, Sweden. Fax: +46 31 786 3512.
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10
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Kullmann S, Goj T, Veit R, Fritsche L, Wagner L, Schneeweiss P, Hoene M, Hoffmann C, Machann J, Niess A, Preissl H, Birkenfeld AL, Peter A, Häring HU, Fritsche A, Moller A, Weigert C, Heni M. Exercise restores brain insulin sensitivity in sedentary adults who are overweight and obese. JCI Insight 2022; 7:161498. [PMID: 36134657 DOI: 10.1172/jci.insight.161498] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2022] [Accepted: 08/04/2022] [Indexed: 11/17/2022] Open
Abstract
BACKGROUNDInsulin resistance of the brain can unfavorably affect long-term weight maintenance and body fat distribution. Little is known if and how brain insulin sensitivity can be restored in humans. We aimed to evaluate the effects of an exercise intervention on insulin sensitivity of the brain and how this relates to exercise-induced changes in whole-body metabolism and behavior.METHODSIn this clinical trial, sedentary participants who were overweight and obese underwent an 8-week supervised aerobic training intervention. Brain insulin sensitivity was assessed in 21 participants (14 women, 7 men; age range 21-59 years; BMI range 27.5-45.5 kg/m2) using functional MRI, combined with intranasal administration of insulin, before and after the intervention.RESULTSThe exercise program resulted in enhanced brain insulin action to the level of a person of healthy weight, demonstrated by increased insulin-induced striatal activity and strengthened hippocampal functional connectivity. Improved brain insulin action correlated with increased mitochondrial respiration in skeletal muscle, reductions in visceral fat and hunger, as well as improved cognition. Mediation analyses suggest that improved brain insulin responsiveness helps mediate the peripheral exercise effects leading to healthier body fat distribution and reduced perception of hunger.CONCLUSIONOur study demonstrates that an 8-week exercise intervention in sedentary individuals can restore insulin action in the brain. Hence, the ameliorating benefits of exercise toward brain insulin resistance may provide an objective therapeutic target in humans in the challenge to reduce diabetes risk factors.TRIAL REGISTRATIONClinicalTrials.gov (NCT03151590).FUNDINGBMBF/DZD 01GI0925.
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Affiliation(s)
- Stephanie Kullmann
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany.,Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Thomas Goj
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany.,Institute for Clinical Chemistry and Pathobiochemistry and
| | - Ralf Veit
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Louise Fritsche
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Lore Wagner
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany
| | - Patrick Schneeweiss
- Department of Sports Medicine, University Hospital Tübingen, Germany.,Interfaculty Research Institute for Sport and Physical Activity, University of Tübingen, Tübingen, Germany
| | - Miriam Hoene
- Institute for Clinical Chemistry and Pathobiochemistry and
| | | | - Jürgen Machann
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany.,Department of Radiology, Section on Experimental Radiology, University Hospital Tübingen, Germany
| | - Andreas Niess
- Department of Sports Medicine, University Hospital Tübingen, Germany.,Interfaculty Research Institute for Sport and Physical Activity, University of Tübingen, Tübingen, Germany
| | - Hubert Preissl
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany.,Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany.,Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Neuherberg, Germany
| | - Andreas L Birkenfeld
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany.,Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Andreas Peter
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany.,Institute for Clinical Chemistry and Pathobiochemistry and
| | - Hans-Ulrich Häring
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany.,Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Andreas Fritsche
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany.,Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Anja Moller
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany.,Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany
| | - Cora Weigert
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany.,Institute for Clinical Chemistry and Pathobiochemistry and
| | - Martin Heni
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Center Munich at the University of Tübingen, Tübingen, Germany.,German Center for Diabetes Research (DZD e.V.), Neuherberg, Germany.,Department of Internal Medicine, Division of Endocrinology, Diabetology and Nephrology, Eberhard Karls University Tübingen, Tübingen, Germany.,Institute for Clinical Chemistry and Pathobiochemistry and.,Division of Endocrinology and Diabetology, Department of Internal Medicine I, Ulm University Hospital, Ulm, Germany
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11
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Somatostatin-evoked Aβ catabolism in the brain: Mechanistic involvement of α-endosulfine-K ATP channel pathway. Mol Psychiatry 2022; 27:1816-1828. [PMID: 34737456 PMCID: PMC9095489 DOI: 10.1038/s41380-021-01368-8] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/28/2021] [Revised: 10/14/2021] [Accepted: 10/15/2021] [Indexed: 12/12/2022]
Abstract
Alzheimer's disease (AD) is characterized by the deposition of amyloid β peptide (Aβ) in the brain. The neuropeptide somatostatin (SST) regulates Aβ catabolism by enhancing neprilysin (NEP)-catalyzed proteolytic degradation. However, the mechanism by which SST regulates NEP activity remains unclear. Here, we identified α-endosulfine (ENSA), an endogenous ligand of the ATP-sensitive potassium (KATP) channel, as a negative regulator of NEP downstream of SST signaling. The expression of ENSA is significantly increased in AD mouse models and in patients with AD. In addition, NEP directly contributes to the degradation of ENSA, suggesting a substrate-dependent feedback loop regulating NEP activity. We also discovered the specific KATP channel subtype that modulates NEP activity, resulting in the Aβ levels altered in the brain. Pharmacological intervention targeting the particular KATP channel attenuated Aβ deposition, with impaired memory function rescued via the NEP activation in our AD mouse model. Our findings provide a mechanism explaining the molecular link between KATP channel and NEP activation, and give new insights into alternative strategies to prevent AD.
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12
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Kim J, Park JH, Shah K, Mitchell SJ, Cho K, Hoe HS. The Anti-diabetic Drug Gliquidone Modulates Lipopolysaccharide-Mediated Microglial Neuroinflammatory Responses by Inhibiting the NLRP3 Inflammasome. Front Aging Neurosci 2021; 13:754123. [PMID: 34776934 PMCID: PMC8587901 DOI: 10.3389/fnagi.2021.754123] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2021] [Accepted: 10/07/2021] [Indexed: 12/22/2022] Open
Abstract
The sulfonylurea drug gliquidone is FDA approved for the treatment of type 2 diabetes. Binding of gliquidone to ATP-sensitive potassium channels (SUR1, Kir6 subunit) in pancreatic β-cells increases insulin release to regulate blood glucose levels. Diabetes has been associated with increased levels of neuroinflammation, and therefore the potential effects of gliquidone on micro- and astroglial neuroinflammatory responses in the brain are of interest. Here, we found that gliquidone suppressed LPS-mediated microgliosis, microglial hypertrophy, and proinflammatory cytokine COX-2 and IL-6 levels in wild-type mice, with smaller effects on astrogliosis. Importantly, gliquidone downregulated the LPS-induced microglial NLRP3 inflammasome and peripheral inflammation in wild-type mice. An investigation of the molecular mechanism of the effects of gliquidone on LPS-stimulated proinflammatory responses showed that in BV2 microglial cells, gliquidone significantly decreased LPS-induced proinflammatory cytokine levels and inhibited ERK/STAT3/NF-κB phosphorylation by altering NLRP3 inflammasome activation. In primary astrocytes, gliquidone selectively affected LPS-mediated proinflammatory cytokine expression and decreased STAT3/NF-κB signaling in an NLRP3-independent manner. These results indicate that gliquidone differentially modulates LPS-induced microglial and astroglial neuroinflammation in BV2 microglial cells, primary astrocytes, and a model of neuroinflammatory disease.
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Affiliation(s)
- Jieun Kim
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea
| | - Jin-Hee Park
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea
| | - Keshvi Shah
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea.,UK-Dementia Research Institute, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Scott John Mitchell
- UK-Dementia Research Institute, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Kwangwook Cho
- UK-Dementia Research Institute, Department of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology and Neuroscience, King's College London, London, United Kingdom
| | - Hyang-Sook Hoe
- Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea.,Department of Brain and Cognitive Sciences, Daegu Gyeongbuk Institute of Science & Technology (DGIST), Daegu, South Korea
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13
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Zhang SY, Li RJW, Lim YM, Batchuluun B, Liu H, Waise TMZ, Lam TKT. FXR in the dorsal vagal complex is sufficient and necessary for upper small intestinal microbiome-mediated changes of TCDCA to alter insulin action in rats. Gut 2021; 70:1675-1683. [PMID: 33087489 DOI: 10.1136/gutjnl-2020-321757] [Citation(s) in RCA: 20] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/08/2020] [Revised: 10/01/2020] [Accepted: 10/02/2020] [Indexed: 12/14/2022]
Abstract
OBJECTIVE Conjugated bile acids are metabolised by upper small intestinal microbiota, and serum levels of taurine-conjugated bile acids are elevated and correlated with insulin resistance in people with type 2 diabetes. However, whether changes in taurine-conjugated bile acids are necessary for small intestinal microbiome to alter insulin action remain unknown. DESIGN We evaluated circulating and specifically brain insulin action using the pancreatic-euglycaemic clamps in high-fat (HF) versus chow fed rats with or without upper small intestinal healthy microbiome transplant. Chemical and molecular gain/loss-of-function experiments targeting specific taurine-conjugated bile acid-induced changes of farnesoid X receptor (FXR) in the brain were performed in parallel. RESULTS We found that short-term HF feeding increased the levels of taurochenodeoxycholic acid (TCDCA, an FXR ligand) in the upper small intestine, ileum, plasma and dorsal vagal complex (DVC) of the brain. Transplantation of upper small intestinal healthy microbiome into the upper small intestine of HF rats not only reversed the rise of TCDCA in all reported tissues but also enhanced the ability of either circulating hyperinsulinaemia or DVC insulin action to lower glucose production. Further, DVC infusion of TCDCA or FXR agonist negated the enhancement of insulin action, while genetic knockdown or chemical inhibition of FXR in the DVC of HF rats reversed insulin resistance. CONCLUSION Our findings indicate that FXR in the DVC is sufficient and necessary for upper small intestinal microbiome-mediated changes of TCDCA to alter insulin action in rats, and highlight a previously unappreciated TCDCA-FXR axis linking gut microbiome and host insulin action.
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Affiliation(s)
- Song-Yang Zhang
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada
| | - Rosa J W Li
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada.,Physiology, University of Toronto, Toronto, Ontario, Canada
| | - Yu-Mi Lim
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada.,Medical Research Institute, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul, Republic of Korea
| | | | - Huiying Liu
- Physiology and Pathophysiology, School of Basic Medical Sciences, Peking University, Beijing, China
| | - T M Zaved Waise
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada
| | - Tony K T Lam
- Toronto General Hospital Research Institute, UHN, Toronto, Ontario, Canada .,Physiology, University of Toronto, Toronto, Ontario, Canada.,Medicine, University of Toronto, Toronto, Ontario, Canada.,Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
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14
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Scherer T, Sakamoto K, Buettner C. Brain insulin signalling in metabolic homeostasis and disease. Nat Rev Endocrinol 2021; 17:468-483. [PMID: 34108679 DOI: 10.1038/s41574-021-00498-x] [Citation(s) in RCA: 57] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 04/22/2021] [Indexed: 02/06/2023]
Abstract
Insulin signalling in the central nervous system regulates energy homeostasis by controlling metabolism in several organs and by coordinating organ crosstalk. Studies performed in rodents, non-human primates and humans over more than five decades using intracerebroventricular, direct hypothalamic or intranasal application of insulin provide evidence that brain insulin action might reduce food intake and, more importantly, regulates energy homeostasis by orchestrating nutrient partitioning. This Review discusses the metabolic pathways that are under the control of brain insulin action and explains how brain insulin resistance contributes to metabolic disease in obesity, the metabolic syndrome and type 2 diabetes mellitus.
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Affiliation(s)
- Thomas Scherer
- Division of Endocrinology and Metabolism, Department of Medicine III, Medical University of Vienna, Vienna, Austria.
| | - Kenichi Sakamoto
- Division of Endocrinology, Metabolism & Nutrition, Department of Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA
| | - Christoph Buettner
- Division of Endocrinology, Metabolism & Nutrition, Department of Medicine, Rutgers Robert Wood Johnson Medical School, New Brunswick, NJ, USA.
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15
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Sánchez-Alegría K, Bastián-Eugenio CE, Vaca L, Arias C. Palmitic acid induces insulin resistance by a mechanism associated with energy metabolism and calcium entry in neuronal cells. FASEB J 2021; 35:e21712. [PMID: 34110637 DOI: 10.1096/fj.202100243r] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/08/2021] [Revised: 04/27/2021] [Accepted: 05/17/2021] [Indexed: 01/05/2023]
Abstract
Palmitic acid (PA) is a saturated fatty acid whose high consumption has been largely associated with the development of different metabolic alterations, such as insulin resistance, metabolic syndrome, and type 2 diabetes. Particularly in the brain, insulin signaling disruption has been linked to cognitive decline and is considered a risk factor for Alzheimer's disease. Cumulative evidence has demonstrated the participation of PA in the molecular cascade underlying cellular insulin resistance in peripheral tissues, but its role in the development of neuronal insulin resistance and the mechanisms involved are not fully understood. It has generally been accepted that the brain does not utilize fatty acids as a primary energy source, but recent evidence shows that neurons possess the machinery for fatty acid β-oxidation. However, it is still unclear under what conditions neurons use fatty acids as energy substrates and the implications of their oxidative metabolism in modifying insulin-stimulated effects. In the present work, we have found that neurons differentiated from human neuroblastoma MSN exposed to high but nontoxic concentrations of PA generate ATP through mitochondrial metabolism, which is associated with an increase in the cytosolic Ca2+ and diminished insulin signaling in neurons. These findings reveal a novel mechanism by which saturated fatty acids produce Ca2+ entry and insulin resistance that may play a causal role in increasing neuronal vulnerability associated with metabolic diseases.
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Affiliation(s)
- Karina Sánchez-Alegría
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Carlos Ernesto Bastián-Eugenio
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Luis Vaca
- Departamento de Genética Molecular, Instituto de Fisiología Celular, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
| | - Clorinda Arias
- Departamento de Medicina Genómica y Toxicología Ambiental, Instituto de Investigaciones Biomédicas, Universidad Nacional Autónoma de México, Ciudad de México, Mexico
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16
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Kaneko K, Lin HY, Fu Y, Saha PK, De la Puente-Gomez AB, Xu Y, Ohinata K, Chen P, Morozov A, Fukuda M. Rap1 in the VMH regulates glucose homeostasis. JCI Insight 2021; 6:142545. [PMID: 33974562 PMCID: PMC8262364 DOI: 10.1172/jci.insight.142545] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2020] [Accepted: 05/05/2021] [Indexed: 12/14/2022] Open
Abstract
The hypothalamus is a critical regulator of glucose metabolism and is capable of correcting diabetes conditions independently of an effect on energy balance. The small GTPase Rap1 in the forebrain is implicated in high-fat diet–induced (HFD-induced) obesity and glucose imbalance. Here, we report that increasing Rap1 activity selectively in the medial hypothalamus elevated blood glucose without increasing the body weight of HFD-fed mice. In contrast, decreasing hypothalamic Rap1 activity protected mice from diet-induced hyperglycemia but did not prevent weight gain. The remarkable glycemic effect of Rap1 was reproduced when Rap1 was specifically deleted in steroidogenic factor-1–positive (SF-1–positive) neurons in the ventromedial hypothalamic nucleus (VMH) known to regulate glucose metabolism. While having no effect on body weight regardless of sex, diet, and age, Rap1 deficiency in the VMH SF1 neurons markedly lowered blood glucose and insulin levels, improved glucose and insulin tolerance, and protected mice against HFD-induced neural leptin resistance and peripheral insulin resistance at the cellular and whole-body levels. Last, acute pharmacological inhibition of brain exchange protein directly activated by cAMP 2, a direct activator of Rap1, corrected glucose imbalance in obese mouse models. Our findings uncover the primary role of VMH Rap1 in glycemic control and implicate Rap1 signaling as a potential target for therapeutic intervention in diabetes.
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Affiliation(s)
- Kentaro Kaneko
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Hsiao-Yun Lin
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Yukiko Fu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Department of Molecular Medicine and Metabolism, Research Institute of Environmental Medicine, Nagoya University, Nagoya, Japan
| | | | - Ana B De la Puente-Gomez
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
| | - Yong Xu
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA.,Department of Molecular and Cellular Biology, Baylor College of Medicine, Houston, Texas, USA
| | - Kousaku Ohinata
- Division of Food Science and Biotechnology, Graduate School of Agriculture, Kyoto University, Uji, Kyoto, Japan
| | - Peter Chen
- Department of Medicine, Division of Pulmonary and Critical Care Medicine, Women's Guild Lung Institute, Cedars-Sinai Medical Center, Los Angeles, California, USA
| | - Alexei Morozov
- Unit on Behavioral Genetics, Laboratory of Molecular Pathophysiology, National Institute of Mental Health, NIH, Maryland, USA.,Fralin Biomedical Research Institute at Virginia Tech Carilion, Roanoke, Virginia, USA
| | - Makoto Fukuda
- Children's Nutrition Research Center, Department of Pediatrics, Baylor College of Medicine, Houston, Texas, USA
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17
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Li RJW, Batchuluun B, Zhang SY, Abraham MA, Wang B, Lim YM, Yue JTY, Lam TKT. Nutrient infusion in the dorsal vagal complex controls hepatic lipid and glucose metabolism in rats. iScience 2021; 24:102366. [PMID: 33870148 PMCID: PMC8044434 DOI: 10.1016/j.isci.2021.102366] [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: 10/20/2020] [Revised: 02/08/2021] [Accepted: 03/24/2021] [Indexed: 11/22/2022] Open
Abstract
Hypothalamic regulation of lipid and glucose homeostasis is emerging, but whether the dorsal vagal complex (DVC) senses nutrients and regulates hepatic nutrient metabolism remains unclear. Here, we found in rats DVC oleic acid infusion suppressed hepatic secretion of triglyceride-rich very-low-density lipoprotein (VLDL-TG), which was disrupted by inhibiting DVC long-chain fatty acyl-CoA synthetase that in parallel disturbed lipid homeostasis during intravenous lipid infusion. DVC glucose infusion elevated local glucose levels similarly as intravenous glucose infusion and suppressed hepatic glucose production. This was independent of lactate metabolism as inhibiting lactate dehydrogenase failed to disrupt glucose sensing and neither could DVC lactate infusion recapitulate glucose effect. DVC oleic acid and glucose infusion failed to lower VLDL-TG secretion and glucose production in high-fat fed rats, while inhibiting DVC farnesoid X receptor enhanced oleic acid but not glucose sensing. Thus, an impairment of DVC nutrient sensing may lead to the disruption of lipid and glucose homeostasis in metabolic syndrome. DVC oleic acid infusion lowers hepatic secretion of VLDL-TG in chow but not HF rats Inhibition of ACSL in the DVC negates lipid sensing DVC glucose infusion lowers hepatic glucose production in chow but not HF rats Inhibition of FXR in the DVC enhances oleic acid but not glucose sensing in HF rats
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Affiliation(s)
- Rosa J W Li
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada.,Toronto General Hospital Research Institute, UHN, MaRS Center, TMDT 101 College Street, 10-705, Toronto, ON M5G 1L7, Canada
| | - Battsetseg Batchuluun
- Toronto General Hospital Research Institute, UHN, MaRS Center, TMDT 101 College Street, 10-705, Toronto, ON M5G 1L7, Canada
| | - Song-Yang Zhang
- Toronto General Hospital Research Institute, UHN, MaRS Center, TMDT 101 College Street, 10-705, Toronto, ON M5G 1L7, Canada
| | - Mona A Abraham
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada.,Toronto General Hospital Research Institute, UHN, MaRS Center, TMDT 101 College Street, 10-705, Toronto, ON M5G 1L7, Canada
| | - Beini Wang
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada.,Toronto General Hospital Research Institute, UHN, MaRS Center, TMDT 101 College Street, 10-705, Toronto, ON M5G 1L7, Canada
| | - Yu-Mi Lim
- Toronto General Hospital Research Institute, UHN, MaRS Center, TMDT 101 College Street, 10-705, Toronto, ON M5G 1L7, Canada.,Medical Research Institute, Kangbuk Samsung Hospital, Sungkyunkwan University School of Medicine, Seoul 03181, Republic of Korea
| | - Jessica T Y Yue
- Department of Physiology, University of Alberta, Edmonton, AB T6G 2H7, Canada
| | - Tony K T Lam
- Department of Physiology, University of Toronto, Toronto, ON M5S 1A8, Canada.,Toronto General Hospital Research Institute, UHN, MaRS Center, TMDT 101 College Street, 10-705, Toronto, ON M5G 1L7, Canada.,Department of Medicine, University of Toronto, Toronto, ON M5S 1A8, Canada.,Banting and Best Diabetes Centre, University of Toronto, Toronto, ON M5G 2C4, Canada
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18
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Lewis GF, Carpentier AC, Pereira S, Hahn M, Giacca A. Direct and indirect control of hepatic glucose production by insulin. Cell Metab 2021; 33:709-720. [PMID: 33765416 DOI: 10.1016/j.cmet.2021.03.007] [Citation(s) in RCA: 44] [Impact Index Per Article: 14.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2021] [Revised: 02/23/2021] [Accepted: 03/05/2021] [Indexed: 01/08/2023]
Abstract
There is general agreement that the acute suppression of hepatic glucose production by insulin is mediated by both a direct and an indirect effect on the liver. There is, however, no consensus regarding the relative magnitude of these effects under physiological conditions. Extensive research over the past three decades in humans and animal models has provided discordant results between these two modes of insulin action. Here, we review the field to make the case that physiologically direct hepatic insulin action dominates acute suppression of glucose production, but that there is also a delayed, second order regulation of this process via extrahepatic effects. We further provide our views regarding the timing, dominance, and physiological relevance of these effects and discuss novel concepts regarding insulin regulation of adipose tissue fatty acid metabolism and central nervous system (CNS) signaling to the liver, as regulators of insulin's extrahepatic effects on glucose production.
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Affiliation(s)
- Gary F Lewis
- Departments of Medicine and Physiology, University of Toronto, Toronto, ON, Canada; Banting & Best Diabetes Centre, University of Toronto, Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada.
| | - Andre C Carpentier
- Division of Endocrinology, Department of Medicine, Centre de Recherche du CHUS, Université de Sherbrooke, Sherbrooke, QC, Canada
| | - Sandra Pereira
- Centre for Addiction and Mental Health and Department of Physiology, University of Toronto, Toronto, ON, Canada
| | - Margaret Hahn
- Banting & Best Diabetes Centre, University of Toronto, Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada; Centre for Addiction and Mental Health and Department of Psychiatry, University of Toronto, Toronto, ON, Canada
| | - Adria Giacca
- Departments of Medicine and Physiology, University of Toronto, Toronto, ON, Canada; Banting & Best Diabetes Centre, University of Toronto, Toronto, ON, Canada; Institute of Medical Sciences, University of Toronto, Toronto, ON, Canada
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19
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Garcia SM, Hirschberg PR, Sarkar P, Siegel DM, Teegala SB, Vail GM, Routh VH. Insulin actions on hypothalamic glucose-sensing neurones. J Neuroendocrinol 2021; 33:e12937. [PMID: 33507001 PMCID: PMC10561189 DOI: 10.1111/jne.12937] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2020] [Revised: 12/22/2020] [Accepted: 12/29/2020] [Indexed: 12/13/2022]
Abstract
Subsequent to the discovery of insulin 100 years ago, great strides have been made in understanding its function, especially in the brain. It is now clear that insulin is a critical regulator of the neuronal circuitry controlling energy balance and glucose homeostasis. This review focuses on the effects of insulin and diabetes on the activity and glucose sensitivity of hypothalamic glucose-sensing neurones. We highlight the role of electrophysiological data in understanding how insulin regulates glucose-sensing neurones. A brief introduction describing the benefits and limitations of the major electrophysiological techniques used to investigate glucose-sensing neurones is provided. The mechanisms by which hypothalamic neurones sense glucose are discussed with an emphasis on those glucose-sensing neurones already shown to be modulated by insulin. Next, the literature pertaining to how insulin alters the activity and glucose sensitivity of these hypothalamic glucose-sensing neurones is described. In addition, the effects of impaired insulin signalling during diabetes and the ramifications of insulin-induced hypoglycaemia on hypothalamic glucose-sensing neurones are covered. To the extent that it is known, we present hypotheses concerning the mechanisms underlying the effects of these insulin-related pathologies. To conclude, electrophysiological data from the hippocampus are evaluated aiming to provide clues regarding how insulin might influence neuronal plasticity in glucose-sensing neurones. Although much has been accomplished subsequent to the discovery of insulin, the work described in our review suggests that the regulation of central glucose sensing by this hormone is both important and understudied.
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Affiliation(s)
- Stephanie M Garcia
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Pamela R Hirschberg
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Pallabi Sarkar
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Dashiel M Siegel
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Suraj B Teegala
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Gwyndolin M Vail
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Vanessa H Routh
- Department of Pharmacology, Physiology and Neuroscience, Rutgers, New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
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20
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Bhat M, Usmani SE, Azhie A, Woo M. Metabolic Consequences of Solid Organ Transplantation. Endocr Rev 2021; 42:171-197. [PMID: 33247713 DOI: 10.1210/endrev/bnaa030] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/18/2020] [Indexed: 12/12/2022]
Abstract
Metabolic complications affect over 50% of solid organ transplant recipients. These include posttransplant diabetes, nonalcoholic fatty liver disease, dyslipidemia, and obesity. Preexisting metabolic disease is further exacerbated with immunosuppression and posttransplant weight gain. Patients transition from a state of cachexia induced by end-organ disease to a pro-anabolic state after transplant due to weight gain, sedentary lifestyle, and suboptimal dietary habits in the setting of immunosuppression. Specific immunosuppressants have different metabolic effects, although all the foundation/maintenance immunosuppressants (calcineurin inhibitors, mTOR inhibitors) increase the risk of metabolic disease. In this comprehensive review, we summarize the emerging knowledge of the molecular pathogenesis of these different metabolic complications, and the potential genetic contribution (recipient +/- donor) to these conditions. These metabolic complications impact both graft and patient survival, particularly increasing the risk of cardiovascular and cancer-associated mortality. The current evidence for prevention and therapeutic management of posttransplant metabolic conditions is provided while highlighting gaps for future avenues in translational research.
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Affiliation(s)
- Mamatha Bhat
- Multi Organ Transplant program and Division of Gastroenterology & Hepatology, University Health Network, Ontario M5G 2N2, Department of Medicine, University of Toronto, Ontario, Canada.,Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Shirine E Usmani
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada.,Division of Endocrinology and Metabolism, Department of Medicine, University Health Network, Ontario, and Sinai Health System, Ontario, University of Toronto, Toronto, Ontario, Canada
| | - Amirhossein Azhie
- Multi Organ Transplant program and Division of Gastroenterology & Hepatology, University Health Network, Ontario M5G 2N2, Department of Medicine, University of Toronto, Ontario, Canada.,Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada
| | - Minna Woo
- Toronto General Hospital Research Institute, University Health Network, Toronto, Ontario, Canada.,Division of Endocrinology and Metabolism, Department of Medicine, University Health Network, Ontario, and Sinai Health System, Ontario, University of Toronto, Toronto, Ontario, Canada
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21
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Kowalchuk C, Castellani L, Kanagsundaram P, McIntyre WB, Asgariroozbehani R, Giacca A, Hahn MK. Olanzapine-induced insulin resistance may occur via attenuation of central K ATP channel-activation. Schizophr Res 2021; 228:112-117. [PMID: 33434724 DOI: 10.1016/j.schres.2020.12.005] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Revised: 09/29/2020] [Accepted: 12/16/2020] [Indexed: 11/20/2022]
Abstract
Antipsychotic use is associated with an increased risk of type 2 diabetes. Recent work suggests antipsychotics can induce insulin resistance immediately and independently of weight gain, and that this may occur via the central nervous system (CNS). We have previously shown that the highly effective and widely prescribed antipsychotic, olanzapine inhibits CNS insulin-mediated suppression of hepatic glucose production, but the mechanisms remain unknown. The ATP-sensitive potassium (KATP) channel is a key metabolic sensor downstream of hypothalamic insulin signalling, involved in the maintenance of glucose homeostasis. Thus, the possibility arises that olanzapine inhibits central KATP channel activation to disrupt glucose metabolism. We replicate that intracerebroventricular (ICV) administration of the KATP channel activator, diazoxide, suppresses hepatic glucose production and additionally demonstrate stimulation of peripheral glucose utilization. We report that olanzapine inhibits the effects of central KATP channel activation resulting in perturbation of whole body insulin sensitivity, specifically via inhibition of glucose utilization, while leaving central KATP channel-mediated suppression of glucose production intact. Perturbation of KATP channel action in the CNS could represent a novel mechanism of antipsychotic-induced diabetes.
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Affiliation(s)
- Chantel Kowalchuk
- Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada; Institute of Medical Science, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Laura Castellani
- Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada
| | - Pruntha Kanagsundaram
- Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada
| | - William Brett McIntyre
- Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada
| | - Roshanak Asgariroozbehani
- Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada; Institute of Medical Science, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada
| | - Adria Giacca
- Department of Physiology, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Banting and Best Diabetes Centre, University of Toronto, 200 Elizabeth Street, Eaton Building, Toronto, Ontario M5G 2C4, Canada
| | - Margaret K Hahn
- Centre for Addiction and Mental Health, 250 College Street, Toronto, Ontario M5T 1R8, Canada; Institute of Medical Science, University of Toronto, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada; Department of Psychiatry, University of Toronto, 250 College Street, Toronto, Ontario M5T 1R8, Canada; Banting and Best Diabetes Centre, University of Toronto, 200 Elizabeth Street, Eaton Building, Toronto, Ontario M5G 2C4, Canada.
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22
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Huang Z, Wang W, Huang L, Guo L, Chen C. Suppression of Insulin Secretion in the Treatment of Obesity: A Systematic Review and Meta-Analysis. Obesity (Silver Spring) 2020; 28:2098-2106. [PMID: 33150747 DOI: 10.1002/oby.22955] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2020] [Revised: 06/22/2020] [Accepted: 06/23/2020] [Indexed: 12/14/2022]
Abstract
OBJECTIVE This proof-of-concept study aimed to evaluate the efficacy and safety of suppression of insulin secretion in the treatment of obesity. METHODS A search of PubMed, Embase, and Cochrane databases was performed to identify randomized controlled trials (up to January 1, 2020) that used drugs that directly suppress insulin secretion (diazoxide or octreotide) in the treatment of obesity. The extracted data were analyzed using random-effects meta-analysis. RESULTS A total of seven randomized controlled trials were included, with four using diazoxide and three using octreotide to suppress insulin secretion. Suppression of insulin secretion significantly reduced fasting insulin level (mean difference: -3.94 mIU/L; 95% CI: -7.40 to -0.47) but slightly increased fasting blood glucose level (mean difference: 0.48 mmol/L; 95% CI: 0.24 to 0.72). Following the suppression of insulin secretion, significant reductions in body weight (mean difference: -3.19 kg; 95% CI: -5.71 to -0.66), BMI (mean difference: -1.65 kg/m2 ; 95% CI: -2.41 to -0.90), and fat mass (mean difference: -5.92 kg; 95% CI: -8.28 to -3.56) were observed compared with placebo in the pooled data. No significant difference in fat-free mass was observed (mean difference: 0.56 kg; 95% CI: -0.40 to 1.52). CONCLUSIONS Results suggest that suppression of insulin secretion may lead to reduced body weight and fat mass with slightly increased blood glucose in individuals with obesity.
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Affiliation(s)
- Zhengxiang Huang
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, Queensland, Australia
| | - Weihao Wang
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, Queensland, Australia
- Department of Endocrinology, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
- Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Lili Huang
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, Queensland, Australia
| | - Lixin Guo
- Department of Endocrinology, Beijing Hospital, National Center of Gerontology, Institute of Geriatric Medicine, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
- Graduate School of Peking Union Medical College, Chinese Academy of Medical Sciences, Beijing, People's Republic of China
| | - Chen Chen
- School of Biomedical Sciences, University of Queensland, St Lucia, Brisbane, Queensland, Australia
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23
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Packer M. Cardioprotective Effects of Sirtuin-1 and Its Downstream Effectors: Potential Role in Mediating the Heart Failure Benefits of SGLT2 (Sodium-Glucose Cotransporter 2) Inhibitors. Circ Heart Fail 2020; 13:e007197. [PMID: 32894987 DOI: 10.1161/circheartfailure.120.007197] [Citation(s) in RCA: 98] [Impact Index Per Article: 24.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
The cardioprotective effects of SGLT2 (sodium-glucose cotransporter 2) inhibitors may be related to their ability to induce a fasting-like paradigm, which triggers the activation of nutrient deprivation pathways to promote cellular homeostasis. The most distinctive metabolic manifestations of this fasting mimicry are enhanced gluconeogenesis and ketogenesis, which are not seen with other antihyperglycemic drugs. The principal molecular stimulus to gluconeogenesis and ketogenesis is activation of SIRT1 (sirtuin-1) and its downstream mediators: PGC-1α (proliferator-activated receptor gamma coactivator 1-alpha) and FGF21 (fibroblast growth factor 21). These three nutrient deprivation sensors exert striking cardioprotective effects in a broad range of experimental models. This benefit appears to be related to their actions to alleviate oxidative stress and promote autophagy-a lysosome-dependent degradative pathway that disposes of dysfunctional organelles that are major sources of cellular injury. Nutrient deprivation sensors are suppressed in states of perceived energy surplus (ie, type 2 diabetes mellitus and chronic heart failure), but SGLT2 inhibitors activate SIRT1/PGC-1α/FGF21 signaling and promote autophagy. This effect may be related to their action to trigger the perception of a system-wide decrease in environmental nutrients, but SGLT2 inhibitors may also upregulate SIRT1, PGC-1α, and FGF21 by a direct effect on the heart. Interestingly, metformin-induced stimulation of AMP-activated protein kinase (a nutrient deprivation sensor that does not promote ketogenesis) has not been shown to reduce heart failure events in clinical trials. Therefore, promotion of ketogenic nutrient deprivation signaling by SGLT2 inhibitors may explain their cardioprotective effects, even though SGLT2 is not expressed in the heart.
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Affiliation(s)
- Milton Packer
- Baylor Heart and Vascular Institute, Baylor University Medical Center, Dallas, TX;and Imperial College, London, United Kingdom
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24
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Packer M. Role of ketogenic starvation sensors in mediating the renal protective effects of SGLT2 inhibitors in type 2 diabetes. J Diabetes Complications 2020; 34:107647. [PMID: 32534886 DOI: 10.1016/j.jdiacomp.2020.107647] [Citation(s) in RCA: 24] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/03/2020] [Revised: 05/15/2020] [Accepted: 05/28/2020] [Indexed: 02/08/2023]
Abstract
Sodium-glucose cotransporter 2 (SGLT2) inhibitors ameliorate the progression of diabetic chronic kidney disease, but the mechanisms underlying this nephroprotective effect have not been fully elucidated. These drugs induce a fasting-like transcriptional paradigm, which includes activation of sirtuin-1 (SIRT1) and its downstream effectors, peroxisome proliferator-activated receptor γ coactivator 1α (PGC-1α) and fibroblast growth factor 21 (FGF21). This triad of enzymes and transcription factors serve as master regulators of nutrient and cellular homeostasis, and each acts to enhance gluconeogenesis, fatty acid oxidation and ketogenesis, the hallmarks of treatment with SGLT2 inhibitors. At the same time, SIRT1/PGC-1α/FGF21 signaling also promotes autophagy, a lysosome-dependent degradative pathway that cleanses the cytosol of dysfunctional organelles. This action alleviates cellular stress, ameliorates inflammation, and is strikingly nephroprotective. Interestingly, type 2 diabetes is characterized by both a deficiency of SIRT1/PGC-1α signaling and an impairment of autophagic flux, thus explaining the high levels of oxidative stress in the diabetic kidney. SIRT1 gene polymorphisms have been linked with an increased risk of diabetic nephropathy in several epidemiological studies. Importantly, there is an inverse relationship between the activity of SGLT2 and signaling through the SIRT1/PGC-1α/FGF21 pathway, and SGLT2 inhibition leads to activation of these ketogenic nutrient deprivation sensors. Therefore, activation of SIRT1/PGC-1α/FGF21 may explain the effect of SGLT2 inhibitors not only to promote ketogenesis, but also to preserve renal function in type 2 diabetes.
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Affiliation(s)
- Milton Packer
- Baylor Heart and Vascular Institute, Baylor University Medical Center, Dallas, TX, USA; Imperial College, London, UK.
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25
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Kullmann S, Kleinridders A, Small DM, Fritsche A, Häring HU, Preissl H, Heni M. Central nervous pathways of insulin action in the control of metabolism and food intake. Lancet Diabetes Endocrinol 2020; 8:524-534. [PMID: 32445739 DOI: 10.1016/s2213-8587(20)30113-3] [Citation(s) in RCA: 108] [Impact Index Per Article: 27.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/11/2019] [Revised: 01/22/2020] [Accepted: 03/20/2020] [Indexed: 12/18/2022]
Abstract
Insulin acts on the CNS to modulate behaviour and systemic metabolism. Disturbances in brain insulin action represent a possible link between metabolic and cognitive health. Current findings from human research suggest that boosting central insulin action in the brain modulates peripheral metabolism, enhancing whole-body insulin sensitivity and suppressing endogenous glucose production. Moreover, central insulin action curbs food intake by reducing the salience of highly palatable food cues and increasing cognitive control. Animal models show that the mesocorticolimbic circuitry is finely tuned in response to insulin, driven mainly by the dopamine system. These mechanisms are impaired in people with obesity, which might increase their risk of developing type 2 diabetes and associated diseases. Overall, current findings highlight the role of insulin action in the brain and its consequences on peripheral metabolism and cognition. Hence, improving central insulin action could represent a therapeutic option for people at an increased risk of developing metabolic and cognitive diseases.
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Affiliation(s)
- Stephanie Kullmann
- Institute for Diabetes Research and Metabolic Diseases, Helmholtz Center Munich, Eberhard Karls University of Tübingen, Tübingen, Germany; Department of Internal Medicine, Division of Endocrinology, Diabetology, and Nephrology, Eberhard Karls University of Tübingen, Tübingen, Germany; German Center for Diabetes Research, Neuherberg, Germany.
| | - André Kleinridders
- German Center for Diabetes Research, Neuherberg, Germany; Central Regulation of Metabolism, German Institute of Human Nutrition Potsdam-Rehbruecke, Nuthetal, Germany
| | - Dana M Small
- Institute for Diabetes Research and Metabolic Diseases, Helmholtz Center Munich, Eberhard Karls University of Tübingen, Tübingen, Germany; Department of Psychiatry, Yale University, New Haven, CT, USA; Modern Diet and Physiology Research Centre, Yale University, New Haven, CT, USA
| | - Andreas Fritsche
- Institute for Diabetes Research and Metabolic Diseases, Helmholtz Center Munich, Eberhard Karls University of Tübingen, Tübingen, Germany; Department of Internal Medicine, Division of Endocrinology, Diabetology, and Nephrology, Eberhard Karls University of Tübingen, Tübingen, Germany; German Center for Diabetes Research, Neuherberg, Germany
| | - Hans-Ulrich Häring
- Institute for Diabetes Research and Metabolic Diseases, Helmholtz Center Munich, Eberhard Karls University of Tübingen, Tübingen, Germany; German Center for Diabetes Research, Neuherberg, Germany
| | - Hubert Preissl
- Institute for Diabetes Research and Metabolic Diseases, Helmholtz Center Munich, Eberhard Karls University of Tübingen, Tübingen, Germany; Department of Internal Medicine, Division of Endocrinology, Diabetology, and Nephrology, Eberhard Karls University of Tübingen, Tübingen, Germany; Department of Pharmacy and Biochemistry, Interfaculty Centre for Pharmacogenomics and Pharma Research, Eberhard Karls University of Tübingen, Tübingen, Germany; German Center for Diabetes Research, Neuherberg, Germany; Institute for Diabetes and Obesity, Helmholtz Diabetes Center, Helmholtz Center Munich, German Research Center for Environmental Health, Neuherberg, Germany
| | - Martin Heni
- Institute for Diabetes Research and Metabolic Diseases, Helmholtz Center Munich, Eberhard Karls University of Tübingen, Tübingen, Germany; Department of Internal Medicine, Division of Endocrinology, Diabetology, and Nephrology, Eberhard Karls University of Tübingen, Tübingen, Germany; German Center for Diabetes Research, Neuherberg, Germany
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26
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Carey M, Lontchi-Yimagou E, Mitchell W, Reda S, Zhang K, Kehlenbrink S, Koppaka S, Maginley SR, Aleksic S, Bhansali S, Huffman DM, Hawkins M. Central K ATP Channels Modulate Glucose Effectiveness in Humans and Rodents. Diabetes 2020; 69:1140-1148. [PMID: 32217610 PMCID: PMC7243288 DOI: 10.2337/db19-1256] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/28/2019] [Accepted: 03/20/2020] [Indexed: 12/23/2022]
Abstract
Hyperglycemia is a potent regulator of endogenous glucose production (EGP). Loss of this "glucose effectiveness" is a major contributor to elevated plasma glucose concentrations in type 2 diabetes (T2D). KATP channels in the central nervous system have been shown to regulate EGP in humans and rodents. We examined the contribution of central KATP channels to glucose effectiveness. Under fixed hormonal conditions (studies using a pancreatic clamp), hyperglycemia suppressed EGP by ∼50% in both humans without diabetes and normal Sprague-Dawley rats. By contrast, antagonism of KATP channels with glyburide significantly reduced the EGP-lowering effect of hyperglycemia in both humans and rats. Furthermore, the effects of glyburide on EGP and gluconeogenic enzymes were abolished in rats by intracerebroventricular administration of the KATP channel agonist diazoxide. These findings indicate that about half of the suppression of EGP by hyperglycemia is mediated by central KATP channels. These central mechanisms may offer a novel therapeutic target for improving glycemic control in subjects with T2D.
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Affiliation(s)
- Michelle Carey
- Albert Einstein College of Medicine, Bronx, NY
- Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD
| | | | | | - Sarah Reda
- Albert Einstein College of Medicine, Bronx, NY
| | - Kehao Zhang
- Albert Einstein College of Medicine, Bronx, NY
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27
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Interaction of glucose sensing and leptin action in the brain. Mol Metab 2020; 39:101011. [PMID: 32416314 PMCID: PMC7267726 DOI: 10.1016/j.molmet.2020.101011] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Revised: 04/27/2020] [Accepted: 05/05/2020] [Indexed: 01/10/2023] Open
Abstract
Background In response to energy abundant or deprived conditions, nutrients and hormones activate hypothalamic pathways to maintain energy and glucose homeostasis. The underlying CNS mechanisms, however, remain elusive in rodents and humans. Scope of review Here, we first discuss brain glucose sensing mechanisms in the presence of a rise or fall of plasma glucose levels, and highlight defects in hypothalamic glucose sensing disrupt in vivo glucose homeostasis in high-fat fed, obese, and/or diabetic conditions. Second, we discuss brain leptin signalling pathways that impact glucose homeostasis in glucose-deprived and excessed conditions, and propose that leptin enhances hypothalamic glucose sensing and restores glucose homeostasis in short-term high-fat fed and/or uncontrolled diabetic conditions. Major conclusions In conclusion, we believe basic studies that investigate the interaction of glucose sensing and leptin action in the brain will address the translational impact of hypothalamic glucose sensing in diabetes and obesity.
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28
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Hirschberg PR, Sarkar P, Teegala SB, Routh VH. Ventromedial hypothalamus glucose-inhibited neurones: A role in glucose and energy homeostasis? J Neuroendocrinol 2020; 32:e12773. [PMID: 31329314 PMCID: PMC7074896 DOI: 10.1111/jne.12773] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/01/2019] [Revised: 06/18/2019] [Accepted: 07/14/2019] [Indexed: 12/20/2022]
Abstract
The ventromedial hypothalamus (VMH) plays a complex role in glucose and energy homeostasis. The VMH is necessary for the counter-regulatory response to hypoglycaemia (CRR) that increases hepatic gluconeogenesis to restore euglycaemia. On the other hand, the VMH also restrains hepatic glucose production during euglycaemia and stimulates peripheral glucose uptake. The VMH is also important for the ability of oestrogen to increase energy expenditure. This latter function is mediated by VMH modulation of the lateral/perifornical hypothalamic area (lateral/perifornical hypothalamus) orexin neurones. Activation of VMH AMP-activated protein kinase (AMPK) is necessary for the CRR. By contrast, VMH AMPK inhibition favours decreased basal glucose levels and is required for oestrogen to increase energy expenditure. Specialised VMH glucose-sensing neurones confer the ability to sense and respond to changes in blood glucose levels. Glucose-excited (GE) neurones increase and glucose-inhibited (GI) neurones decrease their activity as glucose levels rise. VMH GI neurones, in particular, appear to be important in the CRR, although a role for GE neurones cannot be discounted. AMPK mediates glucose sensing in VMH GI neurones suggesting that, although activation of these neurones is important for the CRR, it is necessary to silence them to lower basal glucose levels and enable oestrogen to increase energy expenditure. In support of this, we found that oestrogen reduces activation of VMH GI neurones in low glucose by inhibiting AMPK. In this review, we present the evidence underlying the role of the VMH in glucose and energy homeostasis. We then discuss the role of VMH glucose-sensing neurones in mediating these effects, with a strong emphasis on oestrogenic regulation of glucose sensing and how this may affect glucose and energy homeostasis.
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Affiliation(s)
- Pamela R Hirschberg
- Department of Pharmacology, Physiology and Neurosciences, Rutgers New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Pallabi Sarkar
- Department of Pharmacology, Physiology and Neurosciences, Rutgers New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Suraj B Teegala
- Department of Pharmacology, Physiology and Neurosciences, Rutgers New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
| | - Vanessa H Routh
- Department of Pharmacology, Physiology and Neurosciences, Rutgers New Jersey Medical School, The State University of New Jersey, Newark, NJ, USA
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29
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Abstract
Obesity and type 2 diabetes are the most frequent metabolic disorders, but their causes remain largely unclear. Insulin resistance, the common underlying abnormality, results from imbalance between energy intake and expenditure favouring nutrient-storage pathways, which evolved to maximize energy utilization and preserve adequate substrate supply to the brain. Initially, dysfunction of white adipose tissue and circulating metabolites modulate tissue communication and insulin signalling. However, when the energy imbalance is chronic, mechanisms such as inflammatory pathways accelerate these abnormalities. Here we summarize recent studies providing insights into insulin resistance and increased hepatic gluconeogenesis associated with obesity and type 2 diabetes, focusing on data from humans and relevant animal models.
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30
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Kimonis V, Surampalli A, Wencel M, Gold JA, Cowen NM. A randomized pilot efficacy and safety trial of diazoxide choline controlled-release in patients with Prader-Willi syndrome. PLoS One 2019; 14:e0221615. [PMID: 31545799 PMCID: PMC6756513 DOI: 10.1371/journal.pone.0221615] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/23/2018] [Accepted: 08/08/2019] [Indexed: 12/28/2022] Open
Abstract
Introduction Prader-Willi syndrome (PWS) is a complex genetic condition characterized by hyperphagia, hypotonia, low muscle mass, excess body fat, developmental delays, intellectual disability, behavioral problems, and growth hormone deficiency. This study evaluated the safety and efficacy of orally administered Diazoxide Choline Controlled-Release Tablets (DCCR) in subjects with PWS. Method This was a single-center, Phase II study and included a 10-week Open-Label Treatment Period during which subjects were dose escalated, followed by a 4-week Double-Blind, Placebo-Controlled Treatment Period. Results Five female and eight male overweight or obese, adolescent and adult subjects with genetically-confirmed PWS with an average age of 15.5±2.9 years were enrolled in the study. There was a statistically significant reduction in hyperphagia at the end of the Open-Label Treatment Period (-4.32, n = 11, p = 0.006). The onset of effect on hyperphagia was rapid and greater reductions in hyperphagia were seen in subjects with moderate to severe Baseline hyperphagia (-5.50, n = 6, p = 0.03), in subjects treated with the highest dose (-6.25, n = 4, p = 0.08), and in subjects with moderate to severe Baseline hyperphagia treated with the highest dose (-7.83, n = 3, p = 0.09). DCCR treatment resulted in a reduction in the number of subjects displaying aggressive behaviors (-57.1%, n = 10, p = 0.01), clinically-relevant reductions in fat mass (-1.58 kg, n = 11, p = 0.02) and increases in lean body mass (2.26 kg, n = 11, p = 0.003). There was a corresponding decrease in waist circumference, and trends for improvements in lipids and insulin resistance. The most common adverse events were peripheral edema and transient increases in glucose. Many of the adverse events were common medical complications of PWS and diazoxide. Conclusion DCCR treatment appears to address various unmet needs associated with PWS, including hyperphagia and aggressive behaviors in this proof-of-concept study. If the results were replicated in a larger scale study, DCCR may be a preferred therapeutic option for patients with PWS.
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Affiliation(s)
- Virginia Kimonis
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Univ. of California-Irvine School of Medicine, Orange, California, United States of America
- * E-mail:
| | - Abhilasha Surampalli
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Univ. of California-Irvine School of Medicine, Orange, California, United States of America
| | - Marie Wencel
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Univ. of California-Irvine School of Medicine, Orange, California, United States of America
| | - June-Anne Gold
- Division of Genetics and Genomic Medicine, Department of Pediatrics, Univ. of California-Irvine School of Medicine, Orange, California, United States of America
- Department of Pediatrics, Loma Linda University Medical School, Loma Linda, California, United States of America
| | - Neil M. Cowen
- Soleno Therapeutics, Redwood City, California, United States of America
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31
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Kharade SV, Sanchez-Andres JV, Fulton MG, Shelton EL, Blobaum AL, Engers DW, Hofmann CS, Dadi PK, Lantier L, Jacobson DA, Lindsley CW, Denton JS. Structure-Activity Relationships, Pharmacokinetics, and Pharmacodynamics of the Kir6.2/SUR1-Specific Channel Opener VU0071063. J Pharmacol Exp Ther 2019; 370:350-359. [PMID: 31201216 PMCID: PMC6691189 DOI: 10.1124/jpet.119.257204] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2019] [Accepted: 06/12/2019] [Indexed: 01/14/2023] Open
Abstract
Glucose-stimulated insulin secretion from pancreatic β-cells is controlled by ATP-regulated potassium (KATP) channels composed of Kir6.2 and sulfonylurea receptor 1 (SUR1) subunits. The KATP channel-opener diazoxide is FDA-approved for treating hyperinsulinism and hypoglycemia but suffers from off-target effects on vascular KATP channels and other ion channels. The development of more specific openers would provide critically needed tool compounds for probing the therapeutic potential of Kir6.2/SUR1 activation. Here, we characterize a novel scaffold activator of Kir6.2/SUR1 that our group recently discovered in a high-throughput screen. Optimization efforts with medicinal chemistry identified key structural elements that are essential for VU0071063-dependent opening of Kir6.2/SUR1. VU0071063 has no effects on heterologously expressed Kir6.1/SUR2B channels or ductus arteriole tone, indicating it does not open vascular KATP channels. VU0071063 induces hyperpolarization of β-cell membrane potential and inhibits insulin secretion more potently than diazoxide. VU0071063 exhibits metabolic and pharmacokinetic properties that are favorable for an in vivo probe and is brain penetrant. Administration of VU0071063 inhibits glucose-stimulated insulin secretion and glucose-lowering in mice. Taken together, these studies indicate that VU0071063 is a more potent and specific opener of Kir6.2/SUR1 than diazoxide and should be useful as an in vitro and in vivo tool compound for investigating the therapeutic potential of Kir6.2/SUR1 expressed in the pancreas and brain.
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Affiliation(s)
- Sujay V Kharade
- Departments of Anesthesiology (S.V.K., J.S.D.) and Pediatrics (E.L.S.), Vanderbilt University Medical Center, Nashville, Tennessee; Department of Medicine, Jaume I University, Castellon de la Plana, Spain (J.V.S.-A.); Departments of Chemistry (M.G.F., C.W.L.), Pharmacology (M.G.F., A.L.B., D.W.E., C.S.H., C.W.L., J.S.D.), and Molecular Physiology and Biophysics (P.K.D., D.A.J.), and Mouse Metabolic Phenotyping Core (L.L.), Vanderbilt University, Nashville, Tennessee; and Vanderbilt Center for Neuroscience Drug Discovery, Franklin, Tennessee (D.W.E., A.L.B., C.W.L.)
| | - Juan Vicente Sanchez-Andres
- Departments of Anesthesiology (S.V.K., J.S.D.) and Pediatrics (E.L.S.), Vanderbilt University Medical Center, Nashville, Tennessee; Department of Medicine, Jaume I University, Castellon de la Plana, Spain (J.V.S.-A.); Departments of Chemistry (M.G.F., C.W.L.), Pharmacology (M.G.F., A.L.B., D.W.E., C.S.H., C.W.L., J.S.D.), and Molecular Physiology and Biophysics (P.K.D., D.A.J.), and Mouse Metabolic Phenotyping Core (L.L.), Vanderbilt University, Nashville, Tennessee; and Vanderbilt Center for Neuroscience Drug Discovery, Franklin, Tennessee (D.W.E., A.L.B., C.W.L.)
| | - Mark G Fulton
- Departments of Anesthesiology (S.V.K., J.S.D.) and Pediatrics (E.L.S.), Vanderbilt University Medical Center, Nashville, Tennessee; Department of Medicine, Jaume I University, Castellon de la Plana, Spain (J.V.S.-A.); Departments of Chemistry (M.G.F., C.W.L.), Pharmacology (M.G.F., A.L.B., D.W.E., C.S.H., C.W.L., J.S.D.), and Molecular Physiology and Biophysics (P.K.D., D.A.J.), and Mouse Metabolic Phenotyping Core (L.L.), Vanderbilt University, Nashville, Tennessee; and Vanderbilt Center for Neuroscience Drug Discovery, Franklin, Tennessee (D.W.E., A.L.B., C.W.L.)
| | - Elaine L Shelton
- Departments of Anesthesiology (S.V.K., J.S.D.) and Pediatrics (E.L.S.), Vanderbilt University Medical Center, Nashville, Tennessee; Department of Medicine, Jaume I University, Castellon de la Plana, Spain (J.V.S.-A.); Departments of Chemistry (M.G.F., C.W.L.), Pharmacology (M.G.F., A.L.B., D.W.E., C.S.H., C.W.L., J.S.D.), and Molecular Physiology and Biophysics (P.K.D., D.A.J.), and Mouse Metabolic Phenotyping Core (L.L.), Vanderbilt University, Nashville, Tennessee; and Vanderbilt Center for Neuroscience Drug Discovery, Franklin, Tennessee (D.W.E., A.L.B., C.W.L.)
| | - Anna L Blobaum
- Departments of Anesthesiology (S.V.K., J.S.D.) and Pediatrics (E.L.S.), Vanderbilt University Medical Center, Nashville, Tennessee; Department of Medicine, Jaume I University, Castellon de la Plana, Spain (J.V.S.-A.); Departments of Chemistry (M.G.F., C.W.L.), Pharmacology (M.G.F., A.L.B., D.W.E., C.S.H., C.W.L., J.S.D.), and Molecular Physiology and Biophysics (P.K.D., D.A.J.), and Mouse Metabolic Phenotyping Core (L.L.), Vanderbilt University, Nashville, Tennessee; and Vanderbilt Center for Neuroscience Drug Discovery, Franklin, Tennessee (D.W.E., A.L.B., C.W.L.)
| | - Darren W Engers
- Departments of Anesthesiology (S.V.K., J.S.D.) and Pediatrics (E.L.S.), Vanderbilt University Medical Center, Nashville, Tennessee; Department of Medicine, Jaume I University, Castellon de la Plana, Spain (J.V.S.-A.); Departments of Chemistry (M.G.F., C.W.L.), Pharmacology (M.G.F., A.L.B., D.W.E., C.S.H., C.W.L., J.S.D.), and Molecular Physiology and Biophysics (P.K.D., D.A.J.), and Mouse Metabolic Phenotyping Core (L.L.), Vanderbilt University, Nashville, Tennessee; and Vanderbilt Center for Neuroscience Drug Discovery, Franklin, Tennessee (D.W.E., A.L.B., C.W.L.)
| | - Christopher S Hofmann
- Departments of Anesthesiology (S.V.K., J.S.D.) and Pediatrics (E.L.S.), Vanderbilt University Medical Center, Nashville, Tennessee; Department of Medicine, Jaume I University, Castellon de la Plana, Spain (J.V.S.-A.); Departments of Chemistry (M.G.F., C.W.L.), Pharmacology (M.G.F., A.L.B., D.W.E., C.S.H., C.W.L., J.S.D.), and Molecular Physiology and Biophysics (P.K.D., D.A.J.), and Mouse Metabolic Phenotyping Core (L.L.), Vanderbilt University, Nashville, Tennessee; and Vanderbilt Center for Neuroscience Drug Discovery, Franklin, Tennessee (D.W.E., A.L.B., C.W.L.)
| | - Prasanna K Dadi
- Departments of Anesthesiology (S.V.K., J.S.D.) and Pediatrics (E.L.S.), Vanderbilt University Medical Center, Nashville, Tennessee; Department of Medicine, Jaume I University, Castellon de la Plana, Spain (J.V.S.-A.); Departments of Chemistry (M.G.F., C.W.L.), Pharmacology (M.G.F., A.L.B., D.W.E., C.S.H., C.W.L., J.S.D.), and Molecular Physiology and Biophysics (P.K.D., D.A.J.), and Mouse Metabolic Phenotyping Core (L.L.), Vanderbilt University, Nashville, Tennessee; and Vanderbilt Center for Neuroscience Drug Discovery, Franklin, Tennessee (D.W.E., A.L.B., C.W.L.)
| | - Louise Lantier
- Departments of Anesthesiology (S.V.K., J.S.D.) and Pediatrics (E.L.S.), Vanderbilt University Medical Center, Nashville, Tennessee; Department of Medicine, Jaume I University, Castellon de la Plana, Spain (J.V.S.-A.); Departments of Chemistry (M.G.F., C.W.L.), Pharmacology (M.G.F., A.L.B., D.W.E., C.S.H., C.W.L., J.S.D.), and Molecular Physiology and Biophysics (P.K.D., D.A.J.), and Mouse Metabolic Phenotyping Core (L.L.), Vanderbilt University, Nashville, Tennessee; and Vanderbilt Center for Neuroscience Drug Discovery, Franklin, Tennessee (D.W.E., A.L.B., C.W.L.)
| | - David A Jacobson
- Departments of Anesthesiology (S.V.K., J.S.D.) and Pediatrics (E.L.S.), Vanderbilt University Medical Center, Nashville, Tennessee; Department of Medicine, Jaume I University, Castellon de la Plana, Spain (J.V.S.-A.); Departments of Chemistry (M.G.F., C.W.L.), Pharmacology (M.G.F., A.L.B., D.W.E., C.S.H., C.W.L., J.S.D.), and Molecular Physiology and Biophysics (P.K.D., D.A.J.), and Mouse Metabolic Phenotyping Core (L.L.), Vanderbilt University, Nashville, Tennessee; and Vanderbilt Center for Neuroscience Drug Discovery, Franklin, Tennessee (D.W.E., A.L.B., C.W.L.)
| | - Craig W Lindsley
- Departments of Anesthesiology (S.V.K., J.S.D.) and Pediatrics (E.L.S.), Vanderbilt University Medical Center, Nashville, Tennessee; Department of Medicine, Jaume I University, Castellon de la Plana, Spain (J.V.S.-A.); Departments of Chemistry (M.G.F., C.W.L.), Pharmacology (M.G.F., A.L.B., D.W.E., C.S.H., C.W.L., J.S.D.), and Molecular Physiology and Biophysics (P.K.D., D.A.J.), and Mouse Metabolic Phenotyping Core (L.L.), Vanderbilt University, Nashville, Tennessee; and Vanderbilt Center for Neuroscience Drug Discovery, Franklin, Tennessee (D.W.E., A.L.B., C.W.L.)
| | - Jerod S Denton
- Departments of Anesthesiology (S.V.K., J.S.D.) and Pediatrics (E.L.S.), Vanderbilt University Medical Center, Nashville, Tennessee; Department of Medicine, Jaume I University, Castellon de la Plana, Spain (J.V.S.-A.); Departments of Chemistry (M.G.F., C.W.L.), Pharmacology (M.G.F., A.L.B., D.W.E., C.S.H., C.W.L., J.S.D.), and Molecular Physiology and Biophysics (P.K.D., D.A.J.), and Mouse Metabolic Phenotyping Core (L.L.), Vanderbilt University, Nashville, Tennessee; and Vanderbilt Center for Neuroscience Drug Discovery, Franklin, Tennessee (D.W.E., A.L.B., C.W.L.)
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Lundqvist MH, Almby K, Abrahamsson N, Eriksson JW. Is the Brain a Key Player in Glucose Regulation and Development of Type 2 Diabetes? Front Physiol 2019; 10:457. [PMID: 31133864 PMCID: PMC6524713 DOI: 10.3389/fphys.2019.00457] [Citation(s) in RCA: 22] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2018] [Accepted: 04/01/2019] [Indexed: 01/08/2023] Open
Abstract
Ever since Claude Bernards discovery in the mid 19th-century that a lesion in the floor of the third ventricle in dogs led to altered systemic glucose levels, a role of the CNS in whole-body glucose regulation has been acknowledged. However, this finding was later overshadowed by the isolation of pancreatic hormones in the 20th century. Since then, the understanding of glucose homeostasis and pathology has primarily evolved around peripheral mechanism. Due to scientific advances over these last few decades, however, increasing attention has been given to the possibility of the brain as a key player in glucose regulation and the pathogenesis of metabolic disorders such as type 2 diabetes. Studies of animals have enabled detailed neuroanatomical mapping of CNS structures involved in glucose regulation and key neuronal circuits and intracellular pathways have been identified. Furthermore, the development of neuroimaging techniques has provided methods to measure changes of activity in specific CNS regions upon diverse metabolic challenges in humans. In this narrative review, we discuss the available evidence on the topic. We conclude that there is much evidence in favor of active CNS involvement in glucose homeostasis but the relative importance of central vs. peripheral mechanisms remains to be elucidated. An increased understanding of this field may lead to new CNS-focusing pharmacologic strategies in the treatment of type 2 diabetes.
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Affiliation(s)
| | - Kristina Almby
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
| | | | - Jan W Eriksson
- Department of Medical Sciences, Uppsala University, Uppsala, Sweden
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Wardzinski EK, Friedrichsen L, Dannenberger S, Kistenmacher A, Melchert UH, Jauch-Chara K, Oltmanns KM. Double transcranial direct current stimulation of the brain increases cerebral energy levels and systemic glucose tolerance in men. J Neuroendocrinol 2019; 31:e12688. [PMID: 30659676 DOI: 10.1111/jne.12688] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 12/14/2018] [Accepted: 01/15/2019] [Indexed: 12/31/2022]
Abstract
Transcranial direct current stimulation (tDCS) is a neuromodulatory method that has been tested experimentally and has already been used as an adjuvant therapeutic option to treat a number of neurological disorders and neuropsychiatric diseases. Beyond its well known local effects within the brain, tDCS also transiently promotes systemic glucose uptake and reduces the activity of the neurohormonal stress axes. We aimed to test whether the effects of a single tDCS application could be replicated upon double stimulation to persistently improve systemic glucose tolerance and stress axes activity in humans. In a single-blinded cross-over study, we examined 15 healthy male volunteers. Anodal tDCS vs sham was applied twice in series. Systemic glucose tolerance was investigated by the standard hyperinsulinaemic-euglycaemic glucose clamp procedure, and parameters of neurohormonal stress axes activity were measured. Because tDCS-induced brain energy consumption has been shown to be part of the mechanism underlying the assumed effects, we monitored the cerebral high-energy phosphates ATP and phosphocreatine by 31 phosphorus magnetic resonance spectroscopy. As hypothesised, analyses revealed that double anodal tDCS persistently increases glucose tolerance compared to sham. Moreover, we observed a significant rise in cerebral high-energy phosphate content upon double tDCS. Accordingly, the activity of the neurohormonal stress axes was reduced upon tDCS compared to sham. Our data demonstrate that double tDCS promotes systemic glucose uptake and reduces stress axes activity in healthy humans. These effects suggest that repetitive tDCS may be a future non-pharmacological option for combating glucose intolerance in type 2 diabetes patients.
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Affiliation(s)
- Ewelina K Wardzinski
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Lisa Friedrichsen
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Sina Dannenberger
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Alina Kistenmacher
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Uwe H Melchert
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Kamila Jauch-Chara
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
| | - Kerstin M Oltmanns
- Section of Psychoneurobiology, Center of Brain, Behavior and Metabolism, University of Luebeck, Luebeck, Germany
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Pozo M, Claret M. Hypothalamic Control of Systemic Glucose Homeostasis: The Pancreas Connection. Trends Endocrinol Metab 2018; 29:581-594. [PMID: 29866501 DOI: 10.1016/j.tem.2018.05.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/09/2018] [Revised: 05/10/2018] [Accepted: 05/12/2018] [Indexed: 12/22/2022]
Abstract
Maintenance of glucose homeostasis is mandatory for organismal survival. It is accomplished by complex and coordinated interplay between glucose detection mechanisms and multiple effector systems. The brain, in particular homeostatic regions such as the hypothalamus, plays a crucial role in orchestrating such a highly integral response. We review here current understanding of how the hypothalamus senses glucose availability and participates in systemic glucose homeostasis. We provide an update of the relevant signaling pathways and neuronal subsets involved, as well as of the mechanisms modulating metabolic processes in peripheral tissues such as liver, skeletal muscle, fat, and especially the pancreas. We also discuss the relevance of these networks in human biology and prevalent metabolic conditions such as diabetes and obesity.
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Affiliation(s)
- Macarena Pozo
- Neuronal Control of Metabolism (NeuCoMe) Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain
| | - Marc Claret
- Neuronal Control of Metabolism (NeuCoMe) Laboratory, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain; Centro de Investigación Biomédica en Red (CIBER) de Diabetes y Enfermedades Metabólicas Asociadas (CIBERDEM), 08036 Barcelona, Spain.
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Xiao C, Dash S, Stahel P, Lewis GF. Effects of intranasal insulin on endogenous glucose production in insulin-resistant men. Diabetes Obes Metab 2018. [PMID: 29536605 DOI: 10.1111/dom.13289] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The effects of intranasal insulin on the regulation of endogenous glucose production (EGP) in individuals with insulin resistance were assessed in a single-blind, crossover study. Overweight or obese insulin-resistant men (n = 7; body mass index 35.4 ± 4.4 kg/m2 , homeostatic model assessment of insulin resistance 5.6 ± 1.6) received intranasal spray of either 40 IU insulin lispro or placebo in 2 randomized visits. Acute systemic spillover of intranasal insulin into the circulation was matched with a 30-minute intravenous infusion of insulin lispro in the nasal placebo arm. EGP was assessed under conditions of a pancreatic clamp with a primed, constant infusion of glucose tracer. Under these experimental conditions, compared with placebo, intranasal administration of insulin did not significantly affect plasma glucose concentrations, EGP or glucose disposal in overweight/obese, insulin-resistant men, in contrast to our previous study, in which an equivalent dose of intranasal insulin significantly suppressed EGP in lean, insulin-sensitive men. Insulin resistance is probably associated with impairment in centrally mediated insulin suppression of EGP.
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Affiliation(s)
- Changting Xiao
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Satya Dash
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Priska Stahel
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
| | - Gary F Lewis
- Division of Endocrinology and Metabolism, Departments of Medicine and Physiology, Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
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Kadriu B, Yuan S, Farmer C, Nugent AC, Lener MS, Niciu MJ, Park M, Yazdian A, Ballard ED, Henn FA, Henter ID, Park LT, Zarate CA. Clinical Trial of the Potassium Channel Activator Diazoxide for Major Depressive Disorder Halted Due to Intolerability. J Clin Psychopharmacol 2018; 38:243-246. [PMID: 29601316 PMCID: PMC5903962 DOI: 10.1097/jcp.0000000000000866] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/14/2023]
Abstract
BACKGROUND Some glutamatergic modulators have demonstrated rapid and relatively sustained antidepressant properties in patients with major depressive disorder. Because the potassium channel activator diazoxide increases glutamate uptake via potassium channel activation, we hypothesized that it might exert antidepressant effects by increasing the removal of glutamate from the synaptic cleft, thereby reducing excessive glutamate transmission. METHODS This randomized, double-blind, placebo-controlled, crossover, single-site inpatient clinical study was conducted at the National Institute of Mental Health to assess the efficacy and safety of a 3-week course of diazoxide (200-400 mg daily, twice a day) versus a 3-week course of placebo in 6 participants with treatment-refractory major depressive disorder. The primary clinical outcome measure was change in Montgomery-Asberg Depression Rating Scale score from baseline to posttreatment. Quantitative insulin sensitivity check index, as well as concomitant imaging measures (electroencephalography, proton magnetic resonance spectroscopy, magnetoencephalography), were used as potential surrogate markers of target (KATP channel) engagement. RESULTS The study was halted due to severe adverse effects. Given the small sample size, statistical evaluation of the effect of diazoxide on Montgomery-Asberg Depression Rating Scale scores or the imaging measures was not pursued. Visual inspection of the quantitative insulin sensitivity check index test revealed no evidence of target engagement. CONCLUSIONS Although the results are negative, they are an important addition to the literature in this rapidly changing field.
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Affiliation(s)
- Bashkim Kadriu
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Shiwen Yuan
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Cristan Farmer
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Allison C. Nugent
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Marc S. Lener
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Mark J. Niciu
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Minkyung Park
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Aaron Yazdian
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Elizabeth D. Ballard
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Fritz A. Henn
- Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Ioline D. Henter
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Lawrence T. Park
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
| | - Carlos A Zarate
- Experimental Therapeutics and Pathophysiology Branch, Intramural Research Program, National Institute of Mental Health, Bethesda, MD, USA
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Santoro A, Anjomani Virmouni S, Paradies E, Villalobos Coa VL, Al-Mahdawi S, Khoo M, Porcelli V, Vozza A, Perrone M, Denora N, Taroni F, Merla G, Palmieri L, Pook MA, Marobbio CMT. Effect of diazoxide on Friedreich ataxia models. Hum Mol Genet 2018; 27:992-1001. [PMID: 29325032 DOI: 10.1093/hmg/ddy016] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2017] [Accepted: 01/03/2018] [Indexed: 12/17/2023] Open
Abstract
Friedreich ataxia (FRDA) is an inherited recessive disorder caused by a deficiency in the mitochondrial protein frataxin. There is currently no effective treatment for FRDA available, especially for neurological deficits. In this study, we tested diazoxide, a drug commonly used as vasodilator in the treatment of acute hypertension, on cellular and animal models of FRDA. We first showed that diazoxide increases frataxin protein levels in FRDA lymphoblastoid cell lines, via the mammalian target of rapamycin (mTOR) pathway. We then explored the potential therapeutic effect of diazoxide in frataxin-deficient transgenic YG8sR mice and we found that prolonged oral administration of 3 mpk/d diazoxide was found to be safe, but produced variable effects concerning efficacy. YG8sR mice showed improved beam walk coordination abilities and footprint stride patterns, but a generally reduced locomotor activity. Moreover, they showed significantly increased frataxin expression, improved aconitase activity, and decreased protein oxidation in cerebellum and brain mitochondrial tissue extracts. Further studies are needed before this drug should be considered for FRDA clinical trials.
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Affiliation(s)
- Antonella Santoro
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Consiglio Nazionale delle Ricerche, 70126 Bari, Italy
| | - Sara Anjomani Virmouni
- Department of Life Sciences, College of Health & Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK
| | - Eleonora Paradies
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Consiglio Nazionale delle Ricerche, 70126 Bari, Italy
| | | | - Sahar Al-Mahdawi
- Department of Life Sciences, College of Health & Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK
| | - Mee Khoo
- Department of Life Sciences, College of Health & Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK
| | - Vito Porcelli
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
| | - Angelo Vozza
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
| | - Mara Perrone
- Department of Pharmacy - Drug Sciences, University of Bari, 70125 Bari, Italy
| | - Nunzio Denora
- Department of Pharmacy - Drug Sciences, University of Bari, 70125 Bari, Italy
| | - Franco Taroni
- Unit of Genetics of Neurodegenerative and Metabolic Diseases, Fondazione IRCCS-Istituto Neurologico Carlo Besta, 20133 Milan, Italy
| | - Giuseppe Merla
- Medical Genetics Unit, IRCCS Casa Sollievo della Sofferenza, 71013 San Giovanni, Rotondo, Italy
| | - Luigi Palmieri
- Institute of Biomembranes, Bioenergetics and Molecular Biotechnologies, Consiglio Nazionale delle Ricerche, 70126 Bari, Italy
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
| | - Mark A Pook
- Department of Life Sciences, College of Health & Life Sciences, Brunel University London, Uxbridge UB8 3PH, UK
| | - Carlo M T Marobbio
- Department of Biosciences, Biotechnologies and Biopharmaceutics, University of Bari, 70125 Bari, Italy
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Dash S, Xiao C, Stahel P, Koulajian K, Giacca A, Lewis GF. Evaluation of the specific effects of intranasal glucagon on glucose production and lipid concentration in healthy men during a pancreatic clamp. Diabetes Obes Metab 2018; 20:328-334. [PMID: 28730676 DOI: 10.1111/dom.13069] [Citation(s) in RCA: 6] [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: 05/07/2017] [Revised: 07/01/2017] [Accepted: 07/13/2017] [Indexed: 01/19/2023]
Abstract
AIM To investigate the specific effects of intranasal glucagon (ING) on plasma glucose, endogenous glucose production (EGP) and lipid concentration. METHODS We conducted a single-blind, randomized, crossover study at our academic investigation unit. Under pancreatic clamp conditions with tracer infusion, 1 mg ING or intranasal placebo (INP) was administered to 10 healthy men. As pilot studies showed that ING transiently increased plasma glucagon, we infused intravenous glucagon for 30 minutes along with INP to ensure similar plasma glucagon concentrations between interventions. The main outcome measures were plasma glucose, EGP, free fatty acid (FFA) and triglyceride (TG) concentrations. RESULTS In the presence of similar plasma glucagon concentrations, the increase in plasma glucose under these experimental conditions was attenuated with ING (mean plasma glucose analysis of variance P < .001) with reduction in EGP (P = .027). No significant differences were seen in plasma FFA and TG concentrations. CONCLUSION ING raises plasma glucose but this route of administration attenuates the gluco-stimulatory effect of glucagon by reducing EGP. This observation invites speculation about a potential central nervous system effect of glucagon, which requires further investigation. If ING is developed as a treatment for hypoglycaemia, this attenuated effect on plasma glucose should be taken into account.
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Affiliation(s)
- Satya Dash
- Departments of Medicine and Physiology and the Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
- Division of Endocrinology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Changting Xiao
- Departments of Medicine and Physiology and the Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
- Division of Endocrinology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Priska Stahel
- Departments of Medicine and Physiology and the Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
- Division of Endocrinology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Khajag Koulajian
- Departments of Medicine and Physiology and the Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
- Division of Endocrinology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
| | - Adria Giacca
- Departments of Medicine and Physiology and the Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
- Institute of Medical Science, University of Toronto, Toronto, Ontario, Canada
| | - Gary F Lewis
- Departments of Medicine and Physiology and the Banting and Best Diabetes Centre, University of Toronto, Toronto, Ontario, Canada
- Division of Endocrinology, Department of Medicine, University of Toronto, Toronto, Ontario, Canada
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Jois T, Chen W, Howard V, Harvey R, Youngs K, Thalmann C, Saha P, Chan L, Cowley MA, Sleeman MW. Deletion of hepatic carbohydrate response element binding protein (ChREBP) impairs glucose homeostasis and hepatic insulin sensitivity in mice. Mol Metab 2017; 6:1381-1394. [PMID: 29107286 PMCID: PMC5681238 DOI: 10.1016/j.molmet.2017.07.006] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/23/2017] [Revised: 07/11/2017] [Accepted: 07/12/2017] [Indexed: 11/06/2022] Open
Abstract
OBJECTIVE Carbohydrate response element binding protein (ChREBP) is a transcription factor that responds to glucose and activates genes involved in the glycolytic and lipogenic pathways. Recent studies have linked adipose ChREBP to insulin sensitivity in mice. However, while ChREBP is most highly expressed in the liver, the effect of hepatic ChREBP on insulin sensitivity remains unknown. To clarify the importance of hepatic ChREBP on glucose homeostasis, we have generated a knockout mouse model that lacks this protein specifically in the liver (Liver-ChREBP KO). METHODS Using Liver-ChREBP KO mice, we investigated whether hepatic ChREBP deletion influences insulin sensitivity, glucose homeostasis and the development of hepatic steatosis utilizing various dietary stressors. Furthermore, we determined gene expression changes in response to fasted and fed states in liver, white, and brown adipose tissues. RESULTS Liver-ChREBP KO mice had impaired insulin sensitivity as indicated by reduced glucose infusion to maintain euglycemia during hyperinsulinemic-euglycemic clamps on both chow (25% lower) and high-fat diet (33% lower) (p < 0.05). This corresponded with attenuated suppression of hepatic glucose production. Although Liver-ChREBP KO mice were protected against carbohydrate-induced hepatic steatosis, they displayed worsened glucose tolerance. Liver-ChREBP KO mice did not show the expected gene expression changes in liver in response to fasted and fed states. Interestingly, hepatic ChREBP deletion also resulted in gene expression changes in white and brown adipose tissues, suggesting inter-tissue communication. This included an almost complete abolition of BAT ChREBPβ induction in the fed state (0.15-fold) (p = 0.015) along with reduced lipogenic genes. In contrast, WAT showed inappropriate increases in lipogenic genes in the fasted state along with increased PEPCK1 in both fasted (3.4-fold) and fed (5.1-fold) states (p < 0.0001). CONCLUSIONS Overall, hepatic ChREBP is protective in regards to hepatic insulin sensitivity and whole body glucose homeostasis. Hepatic ChREBP action can influence other peripheral tissues and is likely essential in coordinating the body's response to different feeding states.
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Affiliation(s)
- Tara Jois
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Weiyi Chen
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Victor Howard
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Rebecca Harvey
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Kristina Youngs
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Claudia Thalmann
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Pradip Saha
- Diabetes and Endocrinology Research Center, Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Lawrence Chan
- Diabetes and Endocrinology Research Center, Department of Medicine, Baylor College of Medicine, Houston, TX, USA
| | - Michael A Cowley
- Department of Physiology, Monash University, Clayton, Victoria, Australia; Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
| | - Mark W Sleeman
- Department of Physiology, Monash University, Clayton, Victoria, Australia; Department of Biochemistry and Molecular Biology, Monash University, Clayton, Victoria, Australia; Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia.
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Carey M, Gospin R, Goyal A, Tomuta N, Sandu O, Mbanya A, Lontchi-Yimagou E, Hulkower R, Shamoon H, Gabriely I, Hawkins M. Opioid Receptor Activation Impairs Hypoglycemic Counterregulation in Humans. Diabetes 2017; 66:2764-2773. [PMID: 28860128 PMCID: PMC5652610 DOI: 10.2337/db16-1478] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2016] [Accepted: 08/24/2017] [Indexed: 01/08/2023]
Abstract
Although intensive glycemic control improves outcomes in type 1 diabetes mellitus (T1DM), iatrogenic hypoglycemia limits its attainment. Recurrent and/or antecedent hypoglycemia causes blunting of protective counterregulatory responses, known as hypoglycemia-associated autonomic failure (HAAF). To determine whether and how opioid receptor activation induces HAAF in humans, 12 healthy subjects without diabetes (7 men, age 32.3 ± 2.2 years, BMI 25.1 ± 1.0 kg/m2) participated in two study protocols in random order over two consecutive days. On day 1, subjects received two 120-min infusions of either saline or morphine (0.1 μg/kg/min), separated by a 120-min break (all euglycemic). On day 2, subjects underwent stepped hypoglycemic clamps (nadir 60 mg/dL) with evaluation of counterregulatory hormonal responses, endogenous glucose production (EGP, using 6,6-D2-glucose), and hypoglycemic symptoms. Morphine induced an ∼30% reduction in plasma epinephrine response together with reduced EGP and hypoglycemia-associated symptoms on day 2. Therefore, we report the first studies in humans demonstrating that pharmacologic opioid receptor activation induces some of the clinical and biochemical features of HAAF, thus elucidating the individual roles of various receptors involved in HAAF's development and suggesting novel pharmacologic approaches for safer intensive glycemic control in T1DM.
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Affiliation(s)
- Michelle Carey
- Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, NY
- Center for Drug Evaluation and Research, U.S. Food and Drug Administration, Silver Spring, MD
| | - Rebekah Gospin
- Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, NY
| | - Akankasha Goyal
- Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, NY
| | - Nora Tomuta
- Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, NY
| | - Oana Sandu
- Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, NY
| | - Armand Mbanya
- Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, NY
| | - Eric Lontchi-Yimagou
- Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, NY
| | - Raphael Hulkower
- Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, NY
| | - Harry Shamoon
- Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, NY
| | - Ilan Gabriely
- Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, NY
| | - Meredith Hawkins
- Diabetes Research and Training Center, Albert Einstein College of Medicine, Bronx, NY
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Xiao C, Dash S, Stahel P, Lewis GF. Effects of Intranasal Insulin on Triglyceride-Rich Lipoprotein Particle Production in Healthy Men. Arterioscler Thromb Vasc Biol 2017; 37:1776-1781. [DOI: 10.1161/atvbaha.117.309705] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2017] [Accepted: 07/17/2017] [Indexed: 02/07/2023]
Affiliation(s)
- Changting Xiao
- From the Division of Endocrinology and Metabolism, Department of Medicine and Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, Ontario, Canada
| | - Satya Dash
- From the Division of Endocrinology and Metabolism, Department of Medicine and Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, Ontario, Canada
| | - Priska Stahel
- From the Division of Endocrinology and Metabolism, Department of Medicine and Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, Ontario, Canada
| | - Gary F. Lewis
- From the Division of Endocrinology and Metabolism, Department of Medicine and Department of Physiology, Banting and Best Diabetes Centre, University of Toronto, Ontario, Canada
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Ruud J, Steculorum SM, Brüning JC. Neuronal control of peripheral insulin sensitivity and glucose metabolism. Nat Commun 2017; 8:15259. [PMID: 28469281 PMCID: PMC5418592 DOI: 10.1038/ncomms15259] [Citation(s) in RCA: 125] [Impact Index Per Article: 17.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2016] [Accepted: 03/14/2017] [Indexed: 12/19/2022] Open
Abstract
The central nervous system (CNS) has an important role in the regulation of peripheral insulin sensitivity and glucose homeostasis. Research in this dynamically developing field has progressed rapidly due to techniques allowing targeted transgenesis and neurocircuitry mapping, which have defined the primary responsive neurons, associated molecular mechanisms and downstream neurocircuitries and processes involved. Here we review the brain regions, neurons and molecular mechanisms by which the CNS controls peripheral glucose metabolism, particularly via regulation of liver, brown adipose tissue and pancreatic function, and highlight the potential implications of these regulatory pathways in type 2 diabetes and obesity. The brain controls peripheral glucose metabolism, for example by modulating hepatic gluconeogenesis or by regulating glucose uptake into brown adipose tissue. Here, the authors review the brain regions, neurons and molecular mechanisms involved in these processes, and discuss their relevance to disease.
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Affiliation(s)
- Johan Ruud
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
- Policlinic for Endocrinology, Diabetes and Preventive Medicine (PEDP), University Hospital Cologne, Kerpener Strasse 26, 50924 Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Strasse 26, 50931 Cologne, Germany
| | - Sophie M. Steculorum
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
- Policlinic for Endocrinology, Diabetes and Preventive Medicine (PEDP), University Hospital Cologne, Kerpener Strasse 26, 50924 Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Strasse 26, 50931 Cologne, Germany
| | - Jens C. Brüning
- Department of Neuronal Control of Metabolism, Max Planck Institute for Metabolism Research, Gleueler Strasse 50, 50931 Cologne, Germany
- Policlinic for Endocrinology, Diabetes and Preventive Medicine (PEDP), University Hospital Cologne, Kerpener Strasse 26, 50924 Cologne, Germany
- Excellence Cluster on Cellular Stress Responses in Aging Associated Diseases (CECAD) and Center for Molecular Medicine Cologne (CMMC), University of Cologne, Joseph-Stelzmann-Strasse 26, 50931 Cologne, Germany
- National Center for Diabetes Research (DZD), Ingolstädter Land Strasse 1, 85764 Neuherberg, Germany
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43
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Harada S, Nozaki Y, Matsuura W, Yamazaki Y, Tokuyama S. RETRACTED: Cerebral ischemia-induced elevation of hepatic inflammatory factors accompanied by glucose intolerance suppresses hypothalamic orexin-A-mediated vagus nerve activation. Brain Res 2017; 1661:100-110. [DOI: 10.1016/j.brainres.2017.02.018] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2016] [Revised: 02/06/2017] [Accepted: 02/17/2017] [Indexed: 01/04/2023]
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Affiliation(s)
- Sofiya Gancheva
- Institute for Clinical Diabetology and Leibniz Center for Diabetes Research at Heinrich-Heine University Düsseldorf, German Diabetes Center, Düsseldorf, Germany German Center for Diabetes Research (DZD e.V.), München-Neuherberg, Germany
| | - Michael Roden
- Institute for Clinical Diabetology and Leibniz Center for Diabetes Research at Heinrich-Heine University Düsseldorf, German Diabetes Center, Düsseldorf, Germany German Center for Diabetes Research (DZD e.V.), München-Neuherberg, Germany Department of Endocrinology and Diabetology, Heinrich-Heine University Düsseldorf, Düsseldorf, Germany
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45
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Esterson YB, Carey M, Boucai L, Goyal A, Raghavan P, Zhang K, Mehta D, Feng D, Wu L, Kehlenbrink S, Koppaka S, Kishore P, Hawkins M. Central Regulation of Glucose Production May Be Impaired in Type 2 Diabetes. Diabetes 2016; 65:2569-79. [PMID: 27207526 PMCID: PMC5001178 DOI: 10.2337/db15-1465] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/29/2015] [Accepted: 04/19/2016] [Indexed: 12/21/2022]
Abstract
The challenges of achieving optimal glycemic control in type 2 diabetes highlight the need for new therapies. Inappropriately elevated endogenous glucose production (EGP) is the main source of hyperglycemia in type 2 diabetes. Because activation of central ATP-sensitive potassium (KATP) channels suppresses EGP in nondiabetic rodents and humans, this study examined whether type 2 diabetic humans and rodents retain central regulation of EGP. The KATP channel activator diazoxide was administered in a randomized, placebo-controlled crossover design to eight type 2 diabetic subjects and seven age- and BMI-matched healthy control subjects. Comprehensive measures of glucose turnover and insulin sensitivity were performed during euglycemic pancreatic clamp studies following diazoxide and placebo administration. Complementary rodent clamp studies were performed in Zucker Diabetic Fatty rats. In type 2 diabetic subjects, extrapancreatic KATP channel activation with diazoxide under fixed hormonal conditions failed to suppress EGP, whereas matched control subjects demonstrated a 27% reduction in EGP (P = 0.002) with diazoxide. Diazoxide also failed to suppress EGP in diabetic rats. These results suggest that suppression of EGP by central KATP channel activation may be lost in type 2 diabetes. Restoration of central regulation of glucose metabolism could be a promising therapeutic target to reduce hyperglycemia in type 2 diabetes.
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Affiliation(s)
- Yonah B Esterson
- Diabetes Research and Training Center and Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Michelle Carey
- Diabetes Research and Training Center and Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Laura Boucai
- Diabetes Research and Training Center and Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Akankasha Goyal
- Diabetes Research and Training Center and Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Pooja Raghavan
- Diabetes Research and Training Center and Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Kehao Zhang
- Diabetes Research and Training Center and Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Deeksha Mehta
- Diabetes Research and Training Center and Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Daorong Feng
- Diabetes Research and Training Center and Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Licheng Wu
- Diabetes Research and Training Center and Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Sylvia Kehlenbrink
- Diabetes Research and Training Center and Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Sudha Koppaka
- Diabetes Research and Training Center and Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Preeti Kishore
- Diabetes Research and Training Center and Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Meredith Hawkins
- Diabetes Research and Training Center and Division of Endocrinology, Department of Medicine, Albert Einstein College of Medicine, Bronx, NY
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46
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Martínez-Moreno M, Batlle M, Ortega FJ, Gimeno-Bayón J, Andrade C, Mahy N, Rodríguez MJ. Diazoxide enhances excitotoxicity-induced neurogenesis and attenuates neurodegeneration in the rat non-neurogenic hippocampus. Neuroscience 2016; 333:229-43. [PMID: 27471195 DOI: 10.1016/j.neuroscience.2016.07.032] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Revised: 07/18/2016] [Accepted: 07/19/2016] [Indexed: 12/13/2022]
Abstract
Diazoxide, a well-known mitochondrial KATP channel opener with neuroprotective effects, has been proposed for the effective and safe treatment of neuroinflammation. To test whether diazoxide affects the neurogenesis associated with excitotoxicity in brain injury, we induced lesions by injecting excitotoxic N-methyl-d-aspartate (NMDA) into the rat hippocampus and analyzed the effects of a daily oral administration of diazoxide on the induced lesion. Specific glial and neuronal staining showed that NMDA elicited a strong glial reaction associated with progressive neuronal loss in the whole hippocampal formation. Doublecortin immunohistochemistry and bromo-deoxyuridine (BrdU)-NeuN double immunohistochemistry revealed that NMDA also induced cell proliferation and neurogenesis in the lesioned non-neurogenic hippocampus. Furthermore, glial fibrillary acidic protein (GFAP)-positive cells in the injured hippocampus expressed transcription factor Sp8 indicating that the excitotoxic lesion elicited the migration of progenitors from the subventricular zone and/or the reprograming of reactive astrocytes. Diazoxide treatment attenuated the NMDA-induced hippocampal injury in rats, as demonstrated by decreases in the size of the lesion, neuronal loss and microglial reaction. Diazoxide also increased the number of BrdU/NeuN double-stained cells and elevated the number of Sp8-positive cells in the lesioned hippocampus. These results indicate a role for KATP channel activation in regulating excitotoxicity-induced neurogenesis in brain injury.
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Affiliation(s)
- M Martínez-Moreno
- Departament de Biomedicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Institut de Neurociències, Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - M Batlle
- Departament de Biomedicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Institut de Neurociències, Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - F J Ortega
- Departament de Biomedicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Institut de Neurociències, Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - J Gimeno-Bayón
- Departament de Biomedicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Institut de Neurociències, Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - C Andrade
- Departament de Biomedicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Institut de Neurociències, Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - N Mahy
- Departament de Biomedicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Institut de Neurociències, Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain
| | - M J Rodríguez
- Departament de Biomedicina, Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), Institut de Neurociències, Universitat de Barcelona and Centro de Investigación Biomédica en Red sobre Enfermedades Neurodegenerativas (CIBERNED), Barcelona, Spain.
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Arrieta-Cruz I, Knight CM, Gutiérrez-Juárez R. Acute Exposure of the Mediobasal Hypothalamus to Amyloid-β25-35 Perturbs Hepatic Glucose Metabolism. J Alzheimers Dis 2016; 46:843-8. [PMID: 25869787 DOI: 10.3233/jad-131865] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/21/2023]
Abstract
Patients with Alzheimer's disease (AD) have a higher risk for developing insulin resistance and diabetes. Amyloid plaques, a hallmark of AD, are composed of amyloid-β (Aβ). Because the mediobasal hypothalamus controls hepatic glucose production, we examined the hypothesis that its exposure to Aβ perturbs the regulation of glucose metabolism. The infusion of Aβ25-35, but not its scrambled counterpart, into the mediobasal hypothalamus of young rats, increased circulating glucose as a consequence of enhanced hepatic glucose production during pancreatic clamp studies. These findings suggest a link between AD and alterations of glucose metabolism.
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Affiliation(s)
- Isabel Arrieta-Cruz
- Department of Medicine and Diabetes Research Center, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY, USA.,Department of Basic Research, National Institute of Geriatrics, Ministry of Health, Mexico City, Mexico
| | - Colette M Knight
- Department of Medicine and Diabetes Research Center, Albert Einstein College of Medicine, Yeshiva University, Bronx, NY, USA
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Abstract
Insulin controls hepatic glucose production (HGP) and maintains glucose homeostasis through the direct action of hepatic insulin receptors, as well as the indirect action of insulin receptors in the central nervous system. Insulin acts on insulin receptors in the hypothalamic arcuate nucleus, activates ATP-sensitive potassium channels in a phosphoinositide 3-kinase (PI3K)-dependent manner, induces hyperpolarization of the hypothalamic neurons, and regulates HGP via the vagus nerve. In the liver, central insulin action augments IL-6 expression in Kupffer cells and activates STAT3 transcription factors in hepatocytes. Activated STAT3 suppresses the gene expression of gluconeogenic enzymes, thereby reducing HGP. It has become evident that nutrients such as glucose, fatty acids, and amino acids act upon the hypothalamus together with insulin, affecting HGP. On the other hand, HGP control by central insulin action is impeded in obesity and impeded by insulin resistance due to disturbance of PI3K signaling and inflammation in the hypothalamus or inhibition of STAT3 signaling in the liver. Although the mechanism of control of hepatic gluconeogenic gene expression by central insulin action is conserved across species, its importance in human glucose metabolism has not been made entirely clear and its elucidation is anticipated in the future.
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Affiliation(s)
- Hiroshi Inoue
- Metabolism and Nutrition Research Unit, Institute for Frontier Science Initiative, Kanazawa University, Kanazawa 920-8641, Japan
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Heni M, Kullmann S, Preissl H, Fritsche A, Häring HU. Impaired insulin action in the human brain: causes and metabolic consequences. Nat Rev Endocrinol 2015; 11:701-11. [PMID: 26460339 DOI: 10.1038/nrendo.2015.173] [Citation(s) in RCA: 173] [Impact Index Per Article: 19.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Over the past few years, evidence has accumulated that the human brain is an insulin-sensitive organ. Insulin regulates activity in a limited number of specific brain areas that are important for memory, reward, eating behaviour and the regulation of whole-body metabolism. Accordingly, insulin in the brain modulates cognition, food intake and body weight as well as whole-body glucose, energy and lipid metabolism. However, brain imaging studies have revealed that not everybody responds equally to insulin and that a substantial number of people are brain insulin resistant. In this Review, we provide an overview of the effects of insulin in the brain in humans and the relevance of the effects for physiology. We present emerging evidence for insulin resistance of the human brain. Factors associated with brain insulin resistance such as obesity and increasing age, as well as possible pathogenic factors such as visceral fat, saturated fatty acids, alterations at the blood-brain barrier and certain genetic polymorphisms, are reviewed. In particular, the metabolic consequences of brain insulin resistance are discussed and possible future approaches to overcome brain insulin resistance and thereby prevent or treat obesity and type 2 diabetes mellitus are outlined.
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Affiliation(s)
- Martin Heni
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University, Partners in the German Centre for Diabetes Research (DZD), Otfried-Müller-Street 10, 72076 Tübingen, Germany
| | - Stephanie Kullmann
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Partners in the German Centre for Diabetes Research (DZD), Otfried-Müller-Street 10, 72076 Tübingen, Germany
| | - Hubert Preissl
- Institute for Diabetes Research and Metabolic Diseases of the Helmholtz Centre Munich at the University of Tübingen, Partners in the German Centre for Diabetes Research (DZD), Otfried-Müller-Street 10, 72076 Tübingen, Germany
| | - Andreas Fritsche
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University, Partners in the German Centre for Diabetes Research (DZD), Otfried-Müller-Street 10, 72076 Tübingen, Germany
| | - Hans-Ulrich Häring
- Department of Internal Medicine, Division of Endocrinology, Diabetology, Angiology, Nephrology and Clinical Chemistry, Eberhard Karls University, Partners in the German Centre for Diabetes Research (DZD), Otfried-Müller-Street 10, 72076 Tübingen, Germany
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Xie C, Hu J, Motloch LJ, Karam BS, Akar FG. The Classically Cardioprotective Agent Diazoxide Elicits Arrhythmias in Type 2 Diabetes Mellitus. J Am Coll Cardiol 2015; 66:1144-1156. [PMID: 26337994 DOI: 10.1016/j.jacc.2015.06.1329] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/26/2014] [Revised: 06/06/2015] [Accepted: 06/23/2015] [Indexed: 01/19/2023]
Abstract
BACKGROUND Type 2 diabetes mellitus (T2DM) is associated with an enhanced propensity for ventricular tachyarrhythmias (VTs) under conditions of metabolic demand. Activation of mitochondrial adenosine triphosphate-sensitive potassium (KATP) channels by low-dose diazoxide (DZX) improves hypoglycemia-related complications, metabolic function, and triglyceride and free fatty acid levels and reverses weight gain in T2DM. OBJECTIVES In this study, we hypothesized that DZX prevents ischemia-mediated arrhythmias in T2DM via its putative cardioprotective and antidiabetic property. METHODS Zucker obese diabetic fatty (ZO) rats (n = 43) with T2DM were studied. Controls consisted of Zucker lean (ZL; n = 13) and normal Sprague-Dawley (SprD; n = 30) rats. High-resolution optical action potential mapping was performed before and during challenge with no-flow ischemia for 12 min. RESULTS Electrophysiological properties were relatively stable in T2DM hearts at baseline. In contrast, ischemia uncovered major differences between groups, because action potential duration (APD) in T2DM failed to undergo progressive adaptation to ischemic challenge. DZX promoted the incidence of arrhythmias, because all DZX-treated T2DM hearts exhibited ischemia-induced VTs that persisted on reperfusion. In contrast, untreated T2DM and controls did not exhibit VT during ischemia. Unlike DZX, pinacidil promoted ischemia-mediated arrhythmias in both control and T2DM hearts. Rapid and spatially heterogeneous shortening of APD preceded the onset of arrhythmias in T2DM. DZX-mediated proarrhythmia in T2DM was not related to changes in the messenger ribonucleic acid expression of Kir6.1, Kir6.2, SUR1A, SUR1B, SUR2A, SUR2B, or ROMK (renal outer medullary potassium channel). CONCLUSIONS Ischemia uncovers a paradoxical resistance of T2DM hearts to APD adaptation. DZX reverses this property, resulting in rapid and heterogeneous APD shortening. This promotes reentrant VT during ischemia. DZX should be avoided in diabetic patients at risk of ischemic events.
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Affiliation(s)
- Chaoqin Xie
- Cardiac Bioelectricity Research Laboratory, Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Jun Hu
- Cardiac Bioelectricity Research Laboratory, Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Lukas J Motloch
- Cardiac Bioelectricity Research Laboratory, Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Basil S Karam
- Cardiac Bioelectricity Research Laboratory, Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York
| | - Fadi G Akar
- Cardiac Bioelectricity Research Laboratory, Cardiovascular Institute, Icahn School of Medicine at Mount Sinai, New York, New York
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