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Alshafei M, Morsi M, Reschke J, Rustenbeck I. The Proton Leak of the Inner Mitochondrial Membrane Is Enlarged in Freshly Isolated Pancreatic Islets. Biomedicines 2024; 12:1747. [PMID: 39200212 PMCID: PMC11351158 DOI: 10.3390/biomedicines12081747] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/04/2024] [Revised: 07/22/2024] [Accepted: 07/31/2024] [Indexed: 09/02/2024] Open
Abstract
In a number of investigations on the mechanism of the metabolic amplification of insulin secretion, differences between the response of freshly isolated islets and of islets cultured for one day have been observed. Since no trivial explanation like insufficient numbers of viable cells after cell culture could be found, a more thorough investigation into the mechanisms responsible for the difference was made, concentrating on the function of the mitochondria as the site where the metabolism of nutrient stimulators of secretion forms the signals impacting on the transport and fusion of insulin granules. Using combinations of inhibitors of oxidative phosphorylation, we come to the conclusion that the mitochondrial membrane potential is lower and the exchange of mitochondrial reducing equivalents is faster in freshly isolated islets than in cultured islets. The significantly higher rate of oxygen consumption in fresh islets than in cultured islets (13 vs. 8 pmol/min/islet) was not caused by a different activity of the F1F0-ATPase, but by a larger proton leak. These observations raise the questions as to whether the proton leak is a physiologically regulated pathway and whether its larger size in fresh islets reflects the working condition of the islets within the pancreas.
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Affiliation(s)
- Mohammed Alshafei
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, 38106 Braunschweig, Germany; (M.A.); (M.M.); (J.R.)
| | - Mai Morsi
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, 38106 Braunschweig, Germany; (M.A.); (M.M.); (J.R.)
- Department of Pharmacology, Faculty of Pharmacy, Assiut University, Assiut 71526, Egypt
| | - Julia Reschke
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, 38106 Braunschweig, Germany; (M.A.); (M.M.); (J.R.)
| | - Ingo Rustenbeck
- Institute of Pharmacology, Toxicology and Clinical Pharmacy, Technische Universität Braunschweig, 38106 Braunschweig, Germany; (M.A.); (M.M.); (J.R.)
- PVZ-Center of Pharmaceutical Engineering, Technische Universität Braunschweig, 38106 Braunschweig, Germany
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Kamat V, Grumbine MK, Bao K, Mokate K, Khalil G, Cook D, Clearwater B, Hirst R, Harman J, Boeck M, Fu Z, Smith LEH, Goswami M, Wubben TJ, Walker EM, Zhu J, Soleimanpour SA, Scarlett JM, Robbings BM, Hass D, Hurley JB, Sweet IR. A versatile pumpless multi-channel fluidics system for maintenance and real-time functional assessment of tissue and cells. CELL REPORTS METHODS 2023; 3:100642. [PMID: 37963464 PMCID: PMC10694526 DOI: 10.1016/j.crmeth.2023.100642] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/25/2023] [Revised: 07/24/2023] [Accepted: 10/20/2023] [Indexed: 11/16/2023]
Abstract
To address the needs of the life sciences community and the pharmaceutical industry in pre-clinical drug development to both maintain and continuously assess tissue metabolism and function with simple and rapid systems, we improved on the initial BaroFuse to develop it into a fully functional, pumpless, scalable multi-channel fluidics instrument that continuously measures changes in oxygen consumption and other endpoints in response to test compounds. We and several other laboratories assessed it with a wide range of tissue types including retina, pancreatic islets, liver, and hypothalamus with both aqueous and gaseous test compounds. The setup time was less than an hour for all collaborating groups, and there was close agreement between data obtained from the different laboratories. This easy-to-use system reliably generates real-time metabolic and functional data from tissue and cells in response to test compounds that will address a critical need in basic and applied research.
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Affiliation(s)
- Varun Kamat
- University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA
| | | | - Khang Bao
- EnTox Sciences, Inc., Mercer Island, WA 98040, USA
| | - Kedar Mokate
- University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA
| | - Gamal Khalil
- EnTox Sciences, Inc., Mercer Island, WA 98040, USA
| | - Daniel Cook
- EnTox Sciences, Inc., Mercer Island, WA 98040, USA
| | | | - Richard Hirst
- Technical Assembly Service Corporation, Seattle, WA 98109, USA
| | - Jarrod Harman
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Myriam Boeck
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA; Eye Center, Medical Center, Faculty of Medicine, University of Freiburg, Freiburg im Breisgau, Germany
| | - Zhongjie Fu
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Lois E H Smith
- Department of Ophthalmology, Boston Children's Hospital, Harvard Medical School, Boston, MA 02115, USA
| | - Moloy Goswami
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA
| | - Thomas J Wubben
- Department of Ophthalmology and Visual Sciences, University of Michigan, Ann Arbor, MI 48105, USA
| | - Emily M Walker
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 98195, USA
| | - Jie Zhu
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 98195, USA
| | - Scott A Soleimanpour
- Department of Internal Medicine, University of Michigan, Ann Arbor, MI 98195, USA
| | - Jarrad M Scarlett
- University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; Department of Pediatric Gastroenterology and Hepatology, Seattle Children's Hospital, Seattle, WA 98145, USA
| | - Brian M Robbings
- University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; Department of Biochemistry, University of Washington, Seattle, WA 98109, USA
| | - Daniel Hass
- Department of Biochemistry, University of Washington, Seattle, WA 98109, USA
| | - James B Hurley
- Department of Biochemistry, University of Washington, Seattle, WA 98109, USA
| | - Ian R Sweet
- University of Washington Medicine Diabetes Institute, University of Washington, Seattle, WA 98109, USA; EnTox Sciences, Inc., Mercer Island, WA 98040, USA.
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Yagihashi S. Contribution of animal models to diabetes research: Its history, significance, and translation to humans. J Diabetes Investig 2023; 14:1015-1037. [PMID: 37401013 PMCID: PMC10445217 DOI: 10.1111/jdi.14034] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/17/2023] [Revised: 05/10/2023] [Accepted: 05/16/2023] [Indexed: 07/05/2023] Open
Abstract
Diabetes mellitus is still expanding globally and is epidemic in developing countries. The combat of this plague has caused enormous economic and social burdens related to a lowered quality of life in people with diabetes. Despite recent significant improvements of life expectancy in patients with diabetes, there is still a need for efforts to elucidate the complexities and mechanisms of the disease processes to overcome this difficult disorder. To this end, the use of appropriate animal models in diabetes studies is invaluable for translation to humans and for the development of effective treatment. In this review, a variety of animal models of diabetes with spontaneous onset in particular will be introduced and discussed for their implication in diabetes research.
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Affiliation(s)
- Soroku Yagihashi
- Department of Exploratory Medicine for Nature, Life and HumansToho University School of MedicineChibaJapan
- Department of PathologyHirosaki University Graduate School of MedicineHirosakiJapan
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Wang AN, Carlos J, Fraser GM, McGuire JJ. Zucker Diabetic Sprague Dawley rat (ZDSD): type 2 diabetes translational research model. Exp Physiol 2022; 107:265-282. [PMID: 35178802 PMCID: PMC9314054 DOI: 10.1113/ep089947] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Accepted: 02/02/2022] [Indexed: 11/30/2022]
Abstract
New Findings What is the topic of this review? The Zucker Diabetic‐Sprague Dawley (ZDSD) rat is in the early adoption phase of use by researchers in the fields of diabetes, including prediabetes, obesity and metabolic syndrome. It is essential that physiology researchers choose preclinical models that model human type 2 diabetes appropriately and are aware of the limitations on experimental design. What advances does it highlight? Our review of the scientific literature finds that although sex, age and diets contribute to variability, the ZDSD phenotype and disease progression model the characteristics of humans who have prediabetes and diabetes, including co‐morbidities.
Abstract Type 2 diabetes (T2D) is a prevalent disease and a significant concern for global population health. For persons with T2D, clinical treatments target not only the characteristics of hyperglycaemia and insulin resistance, but also co‐morbidities, such as obesity, cardiovascular and renal disease, neuropathies and skeletal bone conditions. The Zucker Diabetic‐Sprague Dawley (ZDSD) rat is a rodent model developed for experimental studies of T2D. We reviewed the scientific literature to highlight the characteristics of T2D development and the associated phenotypes, such as metabolic syndrome, cardiovascular complications and bone and skeletal pathologies in ZDSD rats. We found that ZDSD phenotype characteristics are independent of leptin receptor signalling. The ZDSD rat develops prediabetes, then progresses to overt diabetes that is accelerated by introduction of a timed high‐fat diet. In male ZDSD rats, glycated haemoglobin (HbA1c) increases at a constant rate from 7 to >30 weeks of age. Diabetic ZDSD rats are moderately hypertensive compared with other rat strains. Diabetes in ZDSD rats leads to endothelial dysfunction in specific vasculatures, impaired wound healing, decreased systolic and diastolic cardiac function, neuropathy and nephropathy. Changes to bone composition and the skeleton increase the risk of bone fractures. Zucker Diabetic‐Sprague Dawley rats have not yet achieved widespread use by researchers. We highlight sex‐related differences in the ZDSD phenotype and gaps in knowledge for future studies. Overall, scientific data support the premise that the phenotype and disease progression in ZDSD rats models the characteristics in humans. We conclude that ZDSD rats are an advantageous model to advance understanding and discovery of treatments for T2D through preclinical research.
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Affiliation(s)
- Andrea N Wang
- Departments of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
| | - Joselia Carlos
- Departments of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
| | - Graham M Fraser
- Division of Biomedical Sciences, Faculty of Medicine, Memorial University, St. John's, Newfoundland, Canada
| | - John J McGuire
- Departments of Medical Biophysics, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada.,Physiology & Pharmacology, Schulich School of Medicine & Dentistry, Western University, London, Ontario, Canada
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Kamat V, Robbings BM, Jung SR, Kelly J, Hurley JB, Bube KP, Sweet IR. Fluidics system for resolving concentration-dependent effects of dissolved gases on tissue metabolism. eLife 2021; 10:e66716. [PMID: 34734803 PMCID: PMC8660022 DOI: 10.7554/elife.66716] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2021] [Accepted: 11/01/2021] [Indexed: 12/15/2022] Open
Abstract
Oxygen (O2) and other dissolved gases such as the gasotransmitters H2S, CO, and NO affect cell metabolism and function. To evaluate effects of dissolved gases on processes in tissue, we developed a fluidics system that controls dissolved gases while simultaneously measuring parameters of electron transport, metabolism, and secretory function. We use pancreatic islets, retina, and liver from rodents to highlight its ability to assess effects of O2 and H2S. Protocols aimed at emulating hypoxia-reperfusion conditions resolved a previously unrecognized transient spike in O2 consumption rate (OCR) following replenishment of O2, and tissue-specific recovery of OCR following hypoxia. The system revealed both inhibitory and stimulatory effects of H2S on insulin secretion rate from isolated islets. The unique ability of this new system to quantify metabolic state and cell function in response to precise changes in dissolved gases provides a powerful platform for cell physiologists to study a wide range of disease states.
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Affiliation(s)
- Varun Kamat
- University of Washington Medicine Diabetes Institute, University of WashingtonSeattleUnited States
| | - Brian M Robbings
- University of Washington Medicine Diabetes Institute, University of WashingtonSeattleUnited States
- Department of Biochemistry, University of WashingtonSeattleUnited States
| | - Seung-Ryoung Jung
- University of Washington Medicine Diabetes Institute, University of WashingtonSeattleUnited States
| | | | - James B Hurley
- Department of Biochemistry, University of WashingtonSeattleUnited States
| | - Kenneth P Bube
- Department of Mathematics, University of WashingtonSeattleUnited States
| | - Ian R Sweet
- University of Washington Medicine Diabetes Institute, University of WashingtonSeattleUnited States
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6
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Control of pancreatic β-cell bioenergetics. Biochem Soc Trans 2018; 46:555-564. [PMID: 29666215 DOI: 10.1042/bst20170505] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2018] [Revised: 03/06/2018] [Accepted: 03/08/2018] [Indexed: 12/12/2022]
Abstract
The canonical model of glucose-stimulated insulin secretion (GSIS) by pancreatic β-cells predicts a glucose-induced rise in the cytosolic ATP/ADP ratio. Such bioenergetic sensitivity to metabolic fuel is unusual as it implies that ATP flux is governed, to a significant extent, by ATP supply, while it is predominantly demand-driven in other cell types. Metabolic control is generally shared between different processes, but potential control of ATP consumption over β-cell bioenergetics has been largely ignored to date. The present paper offers a brief overview of experimental evidence that demonstrates ATP flux control by glucose-fuelled oxidative phosphorylation. Based on old and new data, it is argued that ATP supply does not hold exclusive control over ATP flux, but shares it with ATP demand, and that the distribution of control is flexible. Quantification of the bioenergetic control distribution will be important from basic and clinical perspectives, but precise measurement of the cytosolic ATP/ADP ratio is complicated by adenine nucleotide compartmentalisation. Metabolic control analysis of β-cell bioenergetics will likely clarify the mechanisms by which glucose and fatty acids amplify and potentiate GSIS, respectively. Moreover, such analysis may offer hints as to how ATP flux control shifts from ATP supply to ATP demand during the development of type 2 diabetes, and why prolonged sulfonylurea treatment causes β-cell deterioration.
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Hull RL, Gibson RL, McNamara S, Deutsch GH, Fligner CL, Frevert CW, Ramsey BW, Sanda S. Islet Interleukin-1β Immunoreactivity Is an Early Feature of Cystic Fibrosis That May Contribute to β-Cell Failure. Diabetes Care 2018; 41:823-830. [PMID: 29437698 PMCID: PMC5860832 DOI: 10.2337/dc17-1387] [Citation(s) in RCA: 46] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Accepted: 01/06/2018] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Cystic fibrosis-related diabetes (CFRD) is a common complication of cystic fibrosis (CF), increasing patient morbidity and mortality. Poor understanding of CFRD pathogenesis limits the development of targeted therapies to treat and/or prevent the disease. The aim of this study was to evaluate islet pathology, specifically, inflammation, amyloid deposition, and endocrine cell composition in subjects with CF with diabetes and with CF without diabetes. RESEARCH DESIGN AND METHODS A retrospective analysis of archived pancreas tissue collected at autopsy was conducted using pancreas tissue from subjects with CF and diabetes (CFRD) (n = 18) and CF without diabetes (CF-no DM) (n = 17). Two cohorts of control non-CF subjects were identified, each matched to CFRD and CF-no DM subjects for age, sex, and BMI (non-CF older, n = 20, and non-CF younger, n = 20), respectively. Immunohistochemistry was performed to assess interleukin-1β (IL-1β) and islet hormone (insulin, glucagon, somatostatin, and pancreatic polypeptide) immunoreactivity; histochemistry was performed to quantify amyloid deposition. RESULTS Islet IL-1β immunoreactivity was substantially increased in both CFRD and CF-no DM subjects compared with non-CF subjects and was common in young subjects with CF (≤10 years of age). In contrast, islet amyloid deposition was increased only in CFRD subjects. We also observe abnormal islet hormone immunoreactivity, characterized by increased glucagon immunoreactivity, in CF-no DM and CFRD subjects compared with non-CF subjects. CONCLUSIONS These findings reveal novel molecular pathways and therapeutic targets underlying islet pathology in CF subjects and may be important in developing new approaches to treat CFRD.
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Affiliation(s)
- Rebecca L Hull
- Department of Medicine, University of Washington, Seattle, WA
| | - Ronald L Gibson
- Department of Pediatrics, University of Washington, Seattle, WA
| | - Sharon McNamara
- Department of Pediatrics, University of Washington, Seattle, WA
| | - Gail H Deutsch
- Department of Pathology, University of Washington, Seattle, WA
| | | | - Charles W Frevert
- Department of Medicine, University of Washington, Seattle, WA.,Department of Comparative Medicine, University of Washington, Seattle, WA
| | - Bonnie W Ramsey
- Department of Pediatrics, University of Washington, Seattle, WA
| | - Srinath Sanda
- Department of Pediatrics, University of California, San Francisco, San Francisco, CA .,Diabetes Center, University of California, San Francisco, San Francisco, CA
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Sabatini PV, Speckmann T, Nian C, Glavas MM, Wong CK, Yoon JS, Kin T, Shapiro AMJ, Gibson WT, Verchere CB, Lynn FC. Neuronal PAS Domain Protein 4 Suppression of Oxygen Sensing Optimizes Metabolism during Excitation of Neuroendocrine Cells. Cell Rep 2018; 22:163-174. [PMID: 29298418 DOI: 10.1016/j.celrep.2017.12.033] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2017] [Revised: 10/27/2017] [Accepted: 12/08/2017] [Indexed: 02/07/2023] Open
Abstract
Depolarization of neuroendocrine cells results in calcium influx, which induces vesicle exocytosis and alters gene expression. These processes, along with the restoration of resting membrane potential, are energy intensive. We hypothesized that cellular mechanisms exist to maximize energy production during excitation. Here, we demonstrate that NPAS4, an immediate early basic helix-loop-helix (bHLH)-PAS transcription factor, acts to maximize energy production by suppressing hypoxia-inducible factor 1α (HIF1α). As such, knockout of Npas4 from insulin-producing β cells results in reduced OXPHOS, loss of insulin secretion, β cell dedifferentiation, and type 2 diabetes. NPAS4 plays a similar role in the nutrient-sensing cells of the hypothalamus. Its knockout here results in increased food intake, reduced locomotor activity, and elevated peripheral glucose production. In conclusion, NPAS4 is critical for the coordination of metabolism during the stimulation of electrically excitable cells; its loss leads to the defects in cellular metabolism that underlie the cellular dysfunction that occurs in metabolic disease.
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Affiliation(s)
- Paul V Sabatini
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada; Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - Thilo Speckmann
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada; Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - Cuilan Nian
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada; Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - Maria M Glavas
- Department of Cellular and Physiological Sciences, University of British Columbia, Vancouver, BC, Canada
| | - Chi Kin Wong
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - Ji Soo Yoon
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada; Department of Surgery, University of British Columbia, Vancouver, BC, Canada
| | - Tatsuya Kin
- Department of Surgery and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - A M James Shapiro
- Department of Surgery and Alberta Diabetes Institute, University of Alberta, Edmonton, AB, Canada
| | - William T Gibson
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada; Department of Medical Genetics, University of British Columbia, Vancouver, BC, Canada
| | - C Bruce Verchere
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada; Department of Pathology and Laboratory Medicine, University of British Columbia, Vancouver, BC, Canada
| | - Francis C Lynn
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada; Department of Surgery, University of British Columbia, Vancouver, BC, Canada.
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9
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Oh JM, Woo HW, Kim MK, Lee YH, Shin DH, Shin MH, Choi BY. Dietary total, animal, vegetable calcium and type 2 diabetes incidence among Korean adults: The Korean Multi-Rural Communities Cohort (MRCohort). Nutr Metab Cardiovasc Dis 2017; 27:1152-1164. [PMID: 29167059 DOI: 10.1016/j.numecd.2017.10.005] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2017] [Revised: 08/26/2017] [Accepted: 10/05/2017] [Indexed: 02/06/2023]
Abstract
BACKGROUND AND AIMS Although a possible mechanism for developing type 2 diabetes in relation to calcium intake has been suggested, there is currently little epidemiological evidence on the association between dietary calcium and type 2 diabetes (T2D). This study aimed to evaluate the prospective association between dietary calcium and T2D incidence among adults 40 years of age or over, from the Multi-rural Communities Cohort (MRCohort), South Korea. METHODS AND RESULTS In total, 8313 participants (3033 men and 5280 women) who did not have diabetes at baseline were recruited between 2005 and 2013. The incidence rate ratio (IRR) was estimated using a modified Poisson regression model with a robust error estimator. During follow-up (31,570 person-years), 322 T2D cases were newly diagnosed. Dietary calcium (total and vegetable calcium) were inversely associated with the risk of T2D incidence among women (IRR = 0.61, 95% CI = 0.43-0.86, P for trend = 0.007 in third tertile of baseline total calcium intake comparing to the first tertile; IRR = 0.57, 95% CI = 0.39-0.84, P for trend = 0.006 for baseline vegetable calcium intake), not for men. The tendency of those inverse associations remained in both the normal fasting blood glucose group and the impaired fasting blood glucose group and were independent of obesity, smoking, and magnesium intake. CONCLUSIONS Total and vegetable calcium may be inversely associated with T2D incidence among women, regardless of impaired fasting blood glucose group or normal group. The associations may be potentially dose-responsive. Moderate dietary calcium may be related to lower risk of T2D incidence comparing to low intake group among women.
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Affiliation(s)
- J M Oh
- Department of Preventive Medicine, College of Medicine, Hanyang University, Seoul, South Korea; Institute for Health and Society, Hanyang University, Seoul, South Korea
| | - H W Woo
- Department of Preventive Medicine, College of Medicine, Hanyang University, Seoul, South Korea; Institute for Health and Society, Hanyang University, Seoul, South Korea
| | - M K Kim
- Department of Preventive Medicine, College of Medicine, Hanyang University, Seoul, South Korea; Institute for Health and Society, Hanyang University, Seoul, South Korea.
| | - Y-H Lee
- Department of Preventive Medicine, Institute of Wonkwang Medical Science, Wonkwang University College of Medicine, Iksan, South Korea
| | - D H Shin
- Department of Occupational and Environmental Medicine, Keimyung University Dongsan Medical Center, Daegu, South Korea
| | - M-H Shin
- Department of Preventive Medicine, Chonnam National University Medical School, Gwangju, South Korea
| | - B Y Choi
- Department of Preventive Medicine, College of Medicine, Hanyang University, Seoul, South Korea; Institute for Health and Society, Hanyang University, Seoul, South Korea
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10
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Hull RL, Willard JR, Struck MD, Barrow BM, Brar GS, Andrikopoulos S, Zraika S. High fat feeding unmasks variable insulin responses in male C57BL/6 mouse substrains. J Endocrinol 2017; 233:53-64. [PMID: 28138002 PMCID: PMC5358546 DOI: 10.1530/joe-16-0377] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/09/2017] [Accepted: 01/30/2017] [Indexed: 12/22/2022]
Abstract
Mouse models are widely used for elucidating mechanisms underlying type 2 diabetes. Genetic background profoundly affects metabolic phenotype; therefore, selecting the appropriate model is critical. Although variability in metabolic responses between mouse strains is now well recognized, it also occurs within C57BL/6 mice, of which several substrains exist. This within-strain variability is poorly understood and could emanate from genetic and/or environmental differences. To better define the within-strain variability, we performed the first comprehensive comparison of insulin secretion from C57BL/6 substrains 6J, 6JWehi, 6NJ, 6NHsd, 6NTac and 6NCrl. In vitro, glucose-stimulated insulin secretion correlated with Nnt mutation status, wherein responses were uniformly lower in islets from C57BL/6J vs C57BL/6N mice. In contrast, in vivo insulin responses after 18 weeks of low fat feeding showed no differences among any of the six substrains. When challenged with a high-fat diet for 18 weeks, C57BL/6J substrains responded with a similar increase in insulin release. However, variability was evident among C57BL/6N substrains. Strikingly, 6NJ mice showed no increase in insulin release after high fat feeding, contributing to the ensuing hyperglycemia. The variability in insulin responses among high-fat-fed C57BL/6N mice could not be explained by differences in insulin sensitivity, body weight, food intake or beta-cell area. Rather, as yet unidentified genetic and/or environmental factor(s) are likely contributors. Together, our findings emphasize that caution should be exercised in extrapolating data from in vitro studies to the in vivo situation and inform on selecting the appropriate C57BL/6 substrain for metabolic studies.
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Affiliation(s)
- Rebecca L Hull
- Veterans Affairs Puget Sound Health Care SystemSeattle, Washington, USA
- Division of MetabolismEndocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Joshua R Willard
- Veterans Affairs Puget Sound Health Care SystemSeattle, Washington, USA
| | - Matthias D Struck
- Division of MetabolismEndocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, Washington, USA
| | - Breanne M Barrow
- Veterans Affairs Puget Sound Health Care SystemSeattle, Washington, USA
| | - Gurkirat S Brar
- Veterans Affairs Puget Sound Health Care SystemSeattle, Washington, USA
| | - Sofianos Andrikopoulos
- Department of MedicineUniversity of Melbourne, Austin Hospital, Heidelberg, Victoria, Australia
| | - Sakeneh Zraika
- Veterans Affairs Puget Sound Health Care SystemSeattle, Washington, USA
- Division of MetabolismEndocrinology and Nutrition, Department of Medicine, University of Washington, Seattle, Washington, USA
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11
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Gerencser AA, Mookerjee SA, Jastroch M, Brand MD. Positive Feedback Amplifies the Response of Mitochondrial Membrane Potential to Glucose Concentration in Clonal Pancreatic Beta Cells. Biochim Biophys Acta Mol Basis Dis 2016; 1863:1054-1065. [PMID: 27771512 DOI: 10.1016/j.bbadis.2016.10.015] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/30/2016] [Revised: 10/16/2016] [Accepted: 10/18/2016] [Indexed: 02/07/2023]
Abstract
Analysis of the cellular mechanisms of metabolic disorders, including type 2 diabetes mellitus, is complicated by the large number of reactions and interactions in metabolic networks. Metabolic control analysis with appropriate modularization is a powerful method for simplifying and analyzing these networks. To analyze control of cellular energy metabolism in adherent cell cultures of the INS-1 832/13 pancreatic β-cell model we adapted our microscopy assay of absolute mitochondrial membrane potential (ΔψM) to a fluorescence microplate reader format, and applied it in conjunction with cell respirometry. In these cells the sensitive response of ΔψM to extracellular glucose concentration drives glucose-stimulated insulin secretion. Using metabolic control analysis we identified the control properties that generate this sensitive response. Force-flux relationships between ΔψM and respiration were used to calculate kinetic responses to ΔψM of processes both upstream (glucose oxidation) and downstream (proton leak and ATP turnover) of ΔψM. The analysis revealed that glucose-evoked ΔψM hyperpolarization is amplified by increased glucose oxidation activity caused by factors downstream of ΔψM. At high glucose, the hyperpolarized ΔψM is stabilized almost completely by the action of glucose oxidation, whereas proton leak also contributes to the homeostatic control of ΔψM at low glucose. These findings suggest a strong positive feedback loop in the regulation of β-cell energetics, and a possible regulatory role of proton leak in the fasting state. Analysis of islet bioenergetics from published cases of type 2 diabetes suggests that disruption of this feedback can explain the damaged bioenergetic response of β-cells to glucose. This article is part of a Special Issue entitled: Oxidative Stress and Mitochondrial Quality in Diabetes/Obesity and Critical Illness Spectrum of Diseases - edited by P. Hemachandra Reddy.
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Affiliation(s)
- Akos A Gerencser
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, United States; Image Analyst Software, 43 Nova Lane, Novato, CA 94945, United States.
| | - Shona A Mookerjee
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, United States; Touro University California College of Pharmacy, 1310 Club Drive, Vallejo, CA 94592, United States
| | - Martin Jastroch
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, United States
| | - Martin D Brand
- Buck Institute for Research on Aging, 8001 Redwood Blvd, Novato, CA 94945, United States
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12
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Real-time imaging of intracellular hydrogen peroxide in pancreatic islets. Biochem J 2016; 473:4443-4456. [PMID: 27729543 DOI: 10.1042/bcj20160481] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Revised: 10/07/2016] [Accepted: 10/11/2016] [Indexed: 12/29/2022]
Abstract
A real-time method to measure intracellular hydrogen peroxide (H2O2) would be very impactful in characterizing rapid changes that occur in physiologic and pathophysiologic states. Current methods do not provide the sensitivity, specificity and spatiotemporal resolution needed for such experiments on intact cells. We developed the use of HyPer, a genetic indicator for H2O2 that can be expressed in the cytosol (cyto-HyPer) or the mitochondria (mito-HyPer) of live cells. INS-1 cells or islets were permeabilized and the cytosolic HyPer signal was a linear function of extracellular H2O2, allowing fluorescent cyto-HyPer signals to be converted into H2O2 concentrations. Glucose increased cytosolic H2O2, an effect that was suppressed by overexpression of catalase. Large perturbations in pH can influence the HyPer signal, but inclusion of HEPES [4-(2-hydroxyethyl)-1-piperazineethanesulfonic acid] in the perfusate prevented pH changes, but did not affect glucose-induced cyto-HyPer signals, suggesting that this effect is largely pH-independent. Using the assay, two fundamental questions were addressed. Knockdown of superoxide dismutase 2 (SOD2), the mitochondrial form of SOD, completely suppressed glucose-induced H2O2 Furthermore, glucose also induced mitochondrial superoxide and H2O2 production, which preceded the appearance of cytosolic H2O2 Therefore, glucose-induced H2O2 largely originated from mitochondria. Finally, the glucose-induced HyPer signal was less than 1/20th of that induced by toxic levels of H2O2 Overall, the use of HyPer for real-time imaging allowed resolution of acute changes in intracellular levels of H2O2 and will have great utility for islet studies involving mechanisms of H2O2-mediated signaling and oxidative stress.
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Gerencser AA. Bioenergetic Analysis of Single Pancreatic β-Cells Indicates an Impaired Metabolic Signature in Type 2 Diabetic Subjects. Endocrinology 2015. [PMID: 26204464 DOI: 10.1210/en.2015-1552] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/08/2023]
Abstract
Impaired activation of mitochondrial energy metabolism by glucose has been demonstrated in type 2 diabetic β-cells. The cause of this dysfunction is unknown. The aim of this study was to identify segments of energy metabolism with normal or with altered function in human type 2 diabetes mellitus. The mitochondrial membrane potential (ΔψM), and its response to glucose, is the main driver of mitochondrial ATP synthesis and is hence a central mediator of glucose-induced insulin secretion, but its quantitative determination in β-cells from human donors has not been attempted, due to limitations in assay technology. Here, novel fluorescence microscopic assays are exploited to quantify ΔψM and its response to glucose and other secretagogues in β-cells of dispersed pancreatic islet cells from 4 normal and 3 type 2 diabetic organ donors. Mitochondrial volume densities and the magnitude of ΔψM in low glucose were not consistently altered in diabetic β-cells. However, ΔψM was consistently less responsive to elevation of glucose concentration, whereas the decreased response was not observed with metabolizable secretagogue mixtures that feed directly into the tricarboxylic acid cycle. Single-cell analysis of the heterogeneous responses to metabolizable secretagogues indicated no dysfunction in relaying ΔψM hyperpolarization to plasma membrane potential depolarization in diabetic β-cells. ΔψM of diabetic β-cells was distinctly responsive to acute inhibition of ATP synthesis during glucose stimulation. It is concluded that the mechanistic deficit in glucose-induced insulin secretion and mitochondrial hyperpolarization of diabetic human β-cells is located upstream of the tricarboxylic acid cycle and manifests in dampening the control of ΔψM by glucose metabolism.
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Affiliation(s)
- Akos A Gerencser
- Buck Institute for Research on Aging and Image Analyst Software, Novato, California 94945; and College of Pharmacy, Touro University California, Vallejo, California 94592
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14
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Peterson RG, Jackson CV, Zimmerman K, de Winter W, Huebert N, Hansen MK. Characterization of the ZDSD Rat: A Translational Model for the Study of Metabolic Syndrome and Type 2 Diabetes. J Diabetes Res 2015; 2015:487816. [PMID: 25961053 PMCID: PMC4415477 DOI: 10.1155/2015/487816] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Revised: 09/05/2014] [Accepted: 09/16/2014] [Indexed: 12/16/2022] Open
Abstract
Metabolic syndrome and T2D produce significant health and economic issues. Many available animal models have monogenic leptin pathway mutations that are absent in the human population. Development of the ZDSD rat model was undertaken to produce a model that expresses polygenic obesity and diabetes with an intact leptin pathway. A lean ZDF rat with the propensity for beta-cell failure was crossed with a polygenetically obese Crl:CD (SD) rat. Offspring were selectively inbred for obesity and diabetes for >30 generations. In the current study, ZDSD rats were followed for 6 months; routine clinical metabolic endpoints were included throughout the study. In the prediabetic metabolic syndrome phase, ZDSD rats exhibited obesity with increased body fat, hyperglycemia, insulin resistance, dyslipidemia, glucose intolerance, and elevated HbA1c. As disease progressed to overt diabetes, ZDSD rats demonstrated elevated glucose levels, abnormal oral glucose tolerance, increases in HbA1c levels, reductions in body weight, increased insulin resistance with decreasing insulin levels, and dyslipidemia. The ZDSD rat develops prediabetic metabolic syndrome and T2D in a manner that mirrors the development of metabolic syndrome and T2D in humans. ZDSD rats will provide a novel, translational animal model for the study of human metabolic diseases and for the development of new therapies.
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Affiliation(s)
- Richard G. Peterson
- PreClinOmics, Inc., 7918 Zionsville Road, Indianapolis, IN 46268, USA
- *Richard G. Peterson:
| | | | - Karen Zimmerman
- PreClinOmics, Inc., 7918 Zionsville Road, Indianapolis, IN 46268, USA
| | - Willem de Winter
- Janssen Research & Development, A Division of Janssen Pharmaceutica NV, Turnhoutseweg 30, 2340 Beerse, Belgium
| | - Norman Huebert
- Janssen Research & Development, LLC, Spring House, PA 19477, USA
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15
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Bogdani M, Johnson PY, Potter-Perigo S, Nagy N, Day AJ, Bollyky PL, Wight TN. Hyaluronan and hyaluronan-binding proteins accumulate in both human type 1 diabetic islets and lymphoid tissues and associate with inflammatory cells in insulitis. Diabetes 2014; 63:2727-43. [PMID: 24677718 PMCID: PMC4113060 DOI: 10.2337/db13-1658] [Citation(s) in RCA: 88] [Impact Index Per Article: 8.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Hyaluronan (HA) is an extracellular matrix glycosaminoglycan that is present in pancreatic islets, but little is known about its involvement in the development of human type 1 diabetes (T1D). We have evaluated whether pancreatic islets and lymphoid tissues of T1D and nondiabetic organ donors differ in the amount and distribution of HA and HA-binding proteins (hyaladherins), such as inter-α-inhibitor (IαI), versican, and tumor necrosis factor-stimulated gene-6 (TSG-6). HA was dramatically increased both within the islet and outside the islet endocrine cells, juxtaposed to islet microvessels in T1D. In addition, HA was prominent surrounding immune cells in areas of insulitis. IαI and versican were present in HA-rich areas of islets, and both molecules accumulated in diabetic islets and regions exhibiting insulitis. TSG-6 was observed within the islet endocrine cells and in inflammatory infiltrates. These patterns were only observed in tissues from younger donors with disease duration of <10 years. Furthermore, HA and IαI amassed in follicular germinal centers and in T-cell areas in lymph nodes and spleens in T1D patients compared with control subjects. Our observations highlight potential roles for HA and hyaladherins in the pathogenesis of diabetes.
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Affiliation(s)
- Marika Bogdani
- Matrix Biology Program, Benaroya Research Institute, Seattle, WA
| | - Pamela Y Johnson
- Matrix Biology Program, Benaroya Research Institute, Seattle, WA
| | | | - Nadine Nagy
- Matrix Biology Program, Benaroya Research Institute, Seattle, WA
| | - Anthony J Day
- Wellcome Trust Centre for Cell-Matrix Research, Faculty of Life Sciences, University of Manchester, Manchester, U.K
| | - Paul L Bollyky
- Division of Infectious Diseases, Stanford University Medical Center, Stanford, CA
| | - Thomas N Wight
- Matrix Biology Program, Benaroya Research Institute, Seattle, WA
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16
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Rountree AM, Neal AS, Lisowski M, Rizzo N, Radtke J, White S, Luciani DS, Kim F, Hampe CS, Sweet IR. Control of insulin secretion by cytochrome C and calcium signaling in islets with impaired metabolism. J Biol Chem 2014; 289:19110-9. [PMID: 24841202 DOI: 10.1074/jbc.m114.556050] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
Abstract
The aim of the study was to assess the relative control of insulin secretion rate (ISR) by calcium influx and signaling from cytochrome c in islets where, as in diabetes, the metabolic pathways are impaired. This was achieved either by culturing isolated islets at low (3 mm) glucose or by fasting rats prior to the isolation of the islets. Culture in low glucose greatly reduced the glucose response of cytochrome c reduction and translocation and ISR, but did not affect the response to the mitochondrial fuel α-ketoisocaproate. Unexpectedly, glucose-stimulated calcium influx was only slightly reduced in low glucose-cultured islets and was not responsible for the impairment in glucose-stimulated ISR. A glucokinase activator acutely restored cytochrome c reduction and translocation and ISR, independent of effects on calcium influx. Islets from fasted rats had reduced ISR and cytochrome c reduction in response to both glucose and α-ketoisocaproate despite normal responses of calcium. Our data are consistent with the scenario where cytochrome c reduction and translocation are essential signals in the stimulation of ISR, the loss of which can result in impaired ISR even when calcium response is normal.
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Affiliation(s)
- Austin M Rountree
- From the Diabetes and Obesity Center, Department of Medicine, University of Washington, Seattle, Washington 98195 and
| | - Adam S Neal
- From the Diabetes and Obesity Center, Department of Medicine, University of Washington, Seattle, Washington 98195 and
| | - Mark Lisowski
- From the Diabetes and Obesity Center, Department of Medicine, University of Washington, Seattle, Washington 98195 and
| | - Norma Rizzo
- From the Diabetes and Obesity Center, Department of Medicine, University of Washington, Seattle, Washington 98195 and
| | - Jared Radtke
- From the Diabetes and Obesity Center, Department of Medicine, University of Washington, Seattle, Washington 98195 and
| | - Sarah White
- the Department of Surgery, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Dan S Luciani
- the Department of Surgery, University of British Columbia, Vancouver, British Columbia V6T 1Z4, Canada
| | - Francis Kim
- From the Diabetes and Obesity Center, Department of Medicine, University of Washington, Seattle, Washington 98195 and
| | - Christiane S Hampe
- From the Diabetes and Obesity Center, Department of Medicine, University of Washington, Seattle, Washington 98195 and
| | - Ian R Sweet
- From the Diabetes and Obesity Center, Department of Medicine, University of Washington, Seattle, Washington 98195 and
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