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Wang Y, Wang X, Du C, Wang Z, Wang J, Zhou N, Wang B, Tan K, Fan Y, Cao P. Glycolysis and beyond in glucose metabolism: exploring pulmonary fibrosis at the metabolic crossroads. Front Endocrinol (Lausanne) 2024; 15:1379521. [PMID: 38854692 PMCID: PMC11157045 DOI: 10.3389/fendo.2024.1379521] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2024] [Accepted: 05/07/2024] [Indexed: 06/11/2024] Open
Abstract
At present, pulmonary fibrosis (PF) is a prevalent and irreversible lung disease with limited treatment options, and idiopathic pulmonary fibrosis (IPF) is one of its most common forms. Recent research has highlighted PF as a metabolic-related disease, including dysregulated iron, mitochondria, lipid, and glucose homeostasis. Systematic reports on the regulatory roles of glucose metabolism in PF are rare. This study explores the intricate relationships and signaling pathways between glucose metabolic processes and PF, delving into how key factors involved in glucose metabolism regulate PF progression, and the interplay between them. Specifically, we examined various enzymes, such as hexokinase (HK), 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3), pyruvate kinase (PK), and lactate dehydrogenase (LDH), illustrating their regulatory roles in PF. It highlights the significance of lactate, alongside the role of pyruvate dehydrogenase kinase (PDK) and glucose transporters (GLUTs) in modulating pulmonary fibrosis and glucose metabolism. Additionally, critical regulatory factors such as transforming growth factor-beta (TGF-β), interleukin-1 beta (IL-1β), and hypoxia-inducible factor 1 subunit alpha (HIF-1α) were discussed, demonstrating their impact on both PF and glucose metabolic pathways. It underscores the pivotal role of AMP-activated protein kinase (AMPK) in this interplay, drawing connections between diabetes mellitus, insulin, insulin-like growth factors, and peroxisome proliferator-activated receptor gamma (PPARγ) with PF. This study emphasizes the role of key enzymes, regulators, and glucose transporters in fibrogenesis, suggesting the potential of targeting glucose metabolism for the clinical diagnosis and treatment of PF, and proposing new promising avenues for future research and therapeutic development.
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Affiliation(s)
- Yuejiao Wang
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Collaborative Innovation Center for Eco-Environment, Shijiazhuang, Hebei, China
| | - Xue Wang
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Collaborative Innovation Center for Eco-Environment, Shijiazhuang, Hebei, China
| | - Chaoqi Du
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Collaborative Innovation Center for Eco-Environment, Shijiazhuang, Hebei, China
| | - Zeming Wang
- Department of Laboratory, Hebei Provincial People’s Hospital, Shijiazhuang, Hebei, China
| | - Jiahui Wang
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Collaborative Innovation Center for Eco-Environment, Shijiazhuang, Hebei, China
| | - Nan Zhou
- Department of Gynecology, Xingtai People’s Hospital, Xingtai, Hebei, China
| | - Baohua Wang
- Department of Thoracic Surgery, The Second Hospital of Hebei Medical University, Shijiazhuang, Hebei, China
| | - Ke Tan
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Collaborative Innovation Center for Eco-Environment, Shijiazhuang, Hebei, China
| | - Yumei Fan
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Collaborative Innovation Center for Eco-Environment, Shijiazhuang, Hebei, China
| | - Pengxiu Cao
- Ministry of Education Key Laboratory of Molecular and Cellular Biology, Hebei Key Laboratory of Animal Physiology, Biochemistry and Molecular Biology, College of Life Sciences, Hebei Normal University, Hebei Research Center of the Basic Discipline of Cell Biology, Hebei Collaborative Innovation Center for Eco-Environment, Shijiazhuang, Hebei, China
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Dutta S, Shah RB, Singhal S, Dutta SB, Bansal S, Sinha S, Haque M. Metformin: A Review of Potential Mechanism and Therapeutic Utility Beyond Diabetes. Drug Des Devel Ther 2023; 17:1907-1932. [PMID: 37397787 PMCID: PMC10312383 DOI: 10.2147/dddt.s409373] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2023] [Accepted: 06/10/2023] [Indexed: 07/04/2023] Open
Abstract
Metformin has been designated as one of the most crucial first-line therapeutic agents in the management of type 2 diabetes mellitus. Primarily being an antihyperglycemic agent, metformin also has a plethora of pleiotropic effects on various systems and processes. It acts majorly by activating AMPK (Adenosine Monophosphate-Activated Protein Kinase) in the cells and reducing glucose output from the liver. It also decreases advanced glycation end products and reactive oxygen species production in the endothelium apart from regulating the glucose and lipid metabolism in the cardiomyocytes, hence minimizing the cardiovascular risks. Its anticancer, antiproliferative and apoptosis-inducing effects on malignant cells might prove instrumental in the malignancy of organs like the breast, kidney, brain, ovary, lung, and endometrium. Preclinical studies have also shown some evidence of metformin's neuroprotective role in Parkinson's disease, Alzheimer's disease, multiple sclerosis and Huntington's disease. Metformin exerts its pleiotropic effects through varied pathways of intracellular signalling and exact mechanism in the majority of them remains yet to be clearly defined. This article has extensively reviewed the therapeutic benefits of metformin and the details of its mechanism for a molecule of boon in various conditions like diabetes, prediabetes, obesity, polycystic ovarian disease, metabolic derangement in HIV, various cancers and aging.
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Affiliation(s)
- Siddhartha Dutta
- Department of Pharmacology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Rima B Shah
- Department of Pharmacology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Shubha Singhal
- Department of Pharmacology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Sudeshna Banerjee Dutta
- Department of Medical Surgical Nursing, Shri Anand Institute of Nursing, Rajkot, Gujarat, 360005, India
| | - Sumit Bansal
- Department of Anaesthesiology, All India Institute of Medical Sciences, Rajkot, Gujarat, India
| | - Susmita Sinha
- Department of Physiology, Khulna City Medical College and Hospital, Khulna, Bangladesh
| | - Mainul Haque
- Unit of Pharmacology, Faculty of Medicine and Defence Health, Universiti Pertahanan Nasional Malaysia (National Defence University of Malaysia), Kuala Lumpur, 57000, Malaysia
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Metformin, phenformin, and galegine inhibit complex IV activity and reduce glycerol-derived gluconeogenesis. Proc Natl Acad Sci U S A 2022; 119:e2122287119. [PMID: 35238637 PMCID: PMC8916010 DOI: 10.1073/pnas.2122287119] [Citation(s) in RCA: 40] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Metformin is the most commonly prescribed drug for the treatment of type 2 diabetes mellitus, yet the mechanism by which it lowers plasma glucose concentrations has remained elusive. Most studies to date have attributed metformin’s glucose-lowering effects to inhibition of complex I activity. Contrary to this hypothesis, we show that inhibition of complex I activity in vitro and in vivo does not reduce plasma glucose concentrations or inhibit hepatic gluconeogenesis. We go on to show that metformin, and the related guanides/biguanides, phenformin and galegine, inhibit complex IV activity at clinically relevant concentrations, which, in turn, results in inhibition of glycerol-3-phosphate dehydrogenase activity, increased cytosolic redox, and selective inhibition of glycerol-derived hepatic gluconeogenesis both in vitro and in vivo. Metformin exerts its plasma glucose-lowering therapeutic effect primarily through inhibition of hepatic gluconeogenesis. However, the precise molecular mechanism by which metformin inhibits hepatic gluconeogenesis is still unclear. Although inhibition of mitochondrial complex I is frequently invoked as metformin’s primary mechanism of action, the metabolic effects of complex I inhibition have not been thoroughly evaluated in vivo. Here, we show that acute portal infusion of piericidin A, a potent and specific complex I inhibitor, does not reduce hepatic gluconeogenesis in vivo. In contrast, we show that metformin, phenformin, and galegine selectively inhibit hepatic gluconeogenesis from glycerol. Specifically, we show that guanides/biguanides interact with complex IV to reduce its enzymatic activity, leading to indirect inhibition of glycerol-3-phosphate (G3P) dehydrogenase (GPD2), increased cytosolic redox, and reduced glycerol-derived gluconeogenesis. We report that inhibition of complex IV with potassium cyanide replicates the effects of the guanides/biguanides in vitro by selectively reducing glycerol-derived gluconeogenesis via increased cytosolic redox. Finally, we show that complex IV inhibition is sufficient to inhibit G3P-mediated respiration and gluconeogenesis from glycerol. Taken together, we propose a mechanism of metformin action in which complex IV–mediated inhibition of GPD2 reduces glycerol-derived hepatic gluconeogenesis.
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El Massry M, Alaeddine LM, Ali L, Saad C, Eid AA. Metformin: A Growing Journey from Glycemic Control to the Treatment of Alzheimer's Disease and Depression. Curr Med Chem 2021; 28:2328-2345. [PMID: 32900343 DOI: 10.2174/0929867327666200908114902] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2020] [Revised: 06/30/2020] [Accepted: 07/07/2020] [Indexed: 11/22/2022]
Abstract
Metabolic stress, transduced as an altered cellular redox and energy status, presents as the main culprit in many diseases, including diabetes. However, its role in the pathology of neurological disorders is still not fully elucidated. Metformin, a biguanide compound, is an FDA approved antidiabetic drug generally used for the treatment of type 2 diabetes. The recently described wide spectrum of action executed by this drug suggests a potential therapeutic benefit in a panoply of disorders. Current studies imply that metformin could play a neuroprotective role by reversing hallmarks of brain injury (metabolic dysfunction, neuronal dystrophy and cellular loss), in addition to cognitive and behavioral alterations that accompany the onset of certain brain diseases such as Alzheimer's disease (AD) and depression. However, the mechanisms by which metformin exerts its protective effect in neurodegenerative disorders are not yet fully elucidated. The aim of this review is to reexamine the mechanisms through which metformin performs its function while concentrating on its effect on reestablishing homeostasis in a metabolically disturbed milieu. We will also highlight the importance of metabolic stress, not only as a component of many neurological disorders, but also as a primary driving force for neural insult. Of interest, we will explore the involvement of metabolic stress in the pathobiology of AD and depression. The derangement in major metabolic pathways, including AMPK, insulin and glucose transporters, will be explored and the potential therapeutic effects of metformin administration on the reversal of brain injury in such metabolism dependent diseases will be exposed.
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Affiliation(s)
- Mohamed El Massry
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut, Bliss Street, 11-0236, Riad El-Solh 1107-2020, Beirut, Lebanon
| | - Lynn M Alaeddine
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut, Bliss Street, 11-0236, Riad El-Solh 1107-2020, Beirut, Lebanon
| | - Leen Ali
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut, Bliss Street, 11-0236, Riad El-Solh 1107-2020, Beirut, Lebanon
| | - Celine Saad
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut, Bliss Street, 11-0236, Riad El-Solh 1107-2020, Beirut, Lebanon
| | - Assaad A Eid
- Department of Anatomy, Cell Biology and Physiological Sciences, Faculty of Medicine and Medical Center, American University of Beirut, Bliss Street, 11-0236, Riad El-Solh 1107-2020, Beirut, Lebanon
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LaMoia TE, Shulman GI. Cellular and Molecular Mechanisms of Metformin Action. Endocr Rev 2021; 42:77-96. [PMID: 32897388 PMCID: PMC7846086 DOI: 10.1210/endrev/bnaa023] [Citation(s) in RCA: 307] [Impact Index Per Article: 102.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Accepted: 09/04/2020] [Indexed: 02/07/2023]
Abstract
Metformin is a first-line therapy for the treatment of type 2 diabetes, due to its robust glucose-lowering effects, well-established safety profile, and relatively low cost. While metformin has been shown to have pleotropic effects on glucose metabolism, there is a general consensus that the major glucose-lowering effect in patients with type 2 diabetes is mostly mediated through inhibition of hepatic gluconeogenesis. However, despite decades of research, the mechanism by which metformin inhibits this process is still highly debated. A key reason for these discrepant effects is likely due to the inconsistency in dosage of metformin across studies. Widely studied mechanisms of action, such as complex I inhibition leading to AMPK activation, have only been observed in the context of supra-pharmacological (>1 mM) metformin concentrations, which do not occur in the clinical setting. Thus, these mechanisms have been challenged in recent years and new mechanisms have been proposed. Based on the observation that metformin alters cellular redox balance, a redox-dependent mechanism of action has been described by several groups. Recent studies have shown that clinically relevant (50-100 μM) concentrations of metformin inhibit hepatic gluconeogenesis in a substrate-selective manner both in vitro and in vivo, supporting a redox-dependent mechanism of metformin action. Here, we review the current literature regarding metformin's cellular and molecular mechanisms of action.
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Affiliation(s)
- Traci E LaMoia
- Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut.,Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
| | - Gerald I Shulman
- Department of Internal Medicine, Yale School of Medicine, New Haven, Connecticut.,Department of Cellular & Molecular Physiology, Yale School of Medicine, New Haven, Connecticut
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Lin C, Cai X, Yang W, Lv F, Nie L, Ji L. Age, sex, disease severity, and disease duration difference in placebo response: implications from a meta-analysis of diabetes mellitus. BMC Med 2020; 18:322. [PMID: 33190640 PMCID: PMC7667845 DOI: 10.1186/s12916-020-01787-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 09/17/2020] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND The placebo response in patients with diabetes mellitus is very common. A systematic evaluation needs to be updated with the current evidence about the placebo response in diabetes mellitus and the associated factors in clinical trials of anti-diabetic medicine. METHODS Literature research was conducted in Medline, Embase, the Cochrane Central Register of Controlled Trials, and ClinicalTrials.gov for studies published between the date of inception and June 2019. Randomized placebo-controlled trials conducted in type 1and type 2 diabetes mellitus (T1DM/T2DM) were included. Random-effects model and meta-regression analysis were accordingly used. This meta-analysis was registered in PROSPERO as CRD42014009373. RESULTS Significantly weight elevation (effect size (ES) = 0.33 kg, 95% CI, 0.03 to 0.61 kg) was observed in patients with placebo treatments in T1DM subgroup while significantly HbA1c reduction (ES = - 0.12%, 95% CI, - 0.16 to - 0.07%) and weight reduction (ES = - 0.40 kg, 95% CI, - 0.50 to - 0.29 kg) were observed in patients with placebo treatments in T2DM subgroup. Greater HbA1c reduction was observed in patients with injectable placebo treatments (ES = - 0.22%, 95% CI, - 0.32 to - 0.11%) versus oral types (ES = - 0.09%, 95% CI, - 0.14 to - 0.04%) in T2DM (P = 0.03). Older age (β = - 0.01, 95% CI, - 0.02 to - 0.01, P < 0.01) and longer diabetes duration (β = - 0.02, 95% CI, - 0.03 to - 0.21 × 10-2, P = 0.03) was significantly associated with more HbA1c reduction by placebo in T1DM. However, younger age (β = 0.02, 95% CI, 0.01 to 0.03, P = 0.01), lower male percentage (β = 0.01, 95% CI, 0.22 × 10-2, 0.01, P < 0.01), higher baseline BMI (β = - 0.02, 95% CI, - 0.04 to - 0.26 × 10-2, P = 0.02), and higher baseline HbA1c (β = - 0.09, 95% CI, - 0.16 to - 0.01, P = 0.02) were significantly associated with more HbA1c reduction by placebo in T2DM. Shorter diabetes duration (β = 0.06, 95% CI, 0.06 to 0.10, P < 0.01) was significantly associated with more weight reduction by placebo in T2DM. However, the associations between baseline BMI, baseline HbA1c, and placebo response were insignificant after the adjusted analyses. CONCLUSION The placebo response in diabetes mellitus was systematically outlined. Age, sex, disease severity (indirectly reflected by baseline BMI and baseline HbA1c), and disease duration were associated with placebo response in diabetes mellitus. The association between baseline BMI, baseline HbA1c, and placebo response may be the result of regression to the mean.
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Affiliation(s)
- Chu Lin
- Department of Endocrinology and Metabolism, Peking University People's Hospital, No.11 Xizhimen South Street, Xicheng District, Beijing, 100044, China
| | - Xiaoling Cai
- Department of Endocrinology and Metabolism, Peking University People's Hospital, No.11 Xizhimen South Street, Xicheng District, Beijing, 100044, China.
| | - Wenjia Yang
- Department of Endocrinology and Metabolism, Peking University People's Hospital, No.11 Xizhimen South Street, Xicheng District, Beijing, 100044, China
| | - Fang Lv
- Department of Endocrinology and Metabolism, Peking University People's Hospital, No.11 Xizhimen South Street, Xicheng District, Beijing, 100044, China
| | - Lin Nie
- Department of Endocrinology and Metabolism, Beijing Airport Hospital, Beijing, China
| | - Linong Ji
- Department of Endocrinology and Metabolism, Peking University People's Hospital, No.11 Xizhimen South Street, Xicheng District, Beijing, 100044, China.
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Van Nostrand JL, Hellberg K, Luo EC, Van Nostrand EL, Dayn A, Yu J, Shokhirev MN, Dayn Y, Yeo GW, Shaw RJ. AMPK regulation of Raptor and TSC2 mediate metformin effects on transcriptional control of anabolism and inflammation. Genes Dev 2020; 34:1330-1344. [PMID: 32912901 PMCID: PMC7528705 DOI: 10.1101/gad.339895.120] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2020] [Accepted: 08/12/2020] [Indexed: 12/12/2022]
Abstract
Here, Van Nostrand et al. investigated the mechanisms of action of the biguanide drug metformin by using a new RaptorAA mouse model, in which AMPK phospho-serine sites Ser722 and Ser792 of RAPTOR were mutated to alanine. The hepatic transcriptional response in mice on a high-fat diet treated with metformin was largely ablated by AMPK deficiency under the conditions examined, indicating the essential role of this kinase and its targets in metformin action in vivo. Despite being the frontline therapy for type 2 diabetes, the mechanisms of action of the biguanide drug metformin are still being discovered. In particular, the detailed molecular interplays between the AMPK and the mTORC1 pathway in the hepatic benefits of metformin are still ill defined. Metformin-dependent activation of AMPK classically inhibits mTORC1 via TSC/RHEB, but several lines of evidence suggest additional mechanisms at play in metformin inhibition of mTORC1. Here we investigated the role of direct AMPK-mediated serine phosphorylation of RAPTOR in a new RaptorAA mouse model, in which AMPK phospho-serine sites Ser722 and Ser792 of RAPTOR were mutated to alanine. Metformin treatment of primary hepatocytes and intact murine liver requires AMPK regulation of both RAPTOR and TSC2 to fully inhibit mTORC1, and this regulation is critical for both the translational and transcriptional response to metformin. Transcriptionally, AMPK and mTORC1 were both important for regulation of anabolic metabolism and inflammatory programs triggered by metformin treatment. The hepatic transcriptional response in mice on high-fat diet treated with metformin was largely ablated by AMPK deficiency under the conditions examined, indicating the essential role of this kinase and its targets in metformin action in vivo.
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Affiliation(s)
- Jeanine L Van Nostrand
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Kristina Hellberg
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - En-Ching Luo
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92037, USA
| | - Eric L Van Nostrand
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92037, USA
| | - Alina Dayn
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Jingting Yu
- Razavi Newman Integrative Genomics and Bioinformatics Core, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Maxim N Shokhirev
- Razavi Newman Integrative Genomics and Bioinformatics Core, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Yelena Dayn
- Transgenic Core Facility, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
| | - Gene W Yeo
- Department of Cellular and Molecular Medicine, University of California at San Diego, La Jolla, California 92037, USA
| | - Reuben J Shaw
- Molecular and Cell Biology Laboratory, The Salk Institute for Biological Studies, La Jolla, California 92037, USA
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Metformin Lowers Body Weight But Fails to Increase Insulin Sensitivity in Chronic Heart Failure Patients without Diabetes: a Randomized, Double-Blind, Placebo-Controlled Study. Cardiovasc Drugs Ther 2020; 35:491-503. [PMID: 32770520 DOI: 10.1007/s10557-020-07050-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/01/2020] [Indexed: 12/21/2022]
Abstract
PURPOSE The glucose-lowering drug metformin has recently been shown to reduce myocardial oxygen consumption and increase myocardial efficiency in chronic heart failure (HF) patients without diabetes. However, it remains to be established whether these beneficial myocardial effects are associated with metformin-induced alterations in whole-body insulin sensitivity and substrate metabolism. METHODS Eighteen HF patients with reduced ejection fraction and without diabetes (median age, 65 (interquartile range 55-68); ejection fraction 39 ± 6%; HbA1c 5.5 to 6.4%) were randomized to receive metformin (n = 10) or placebo (n = 8) for 3 months. We studied the effects of metformin on whole-body insulin sensitivity using a two-step hyperinsulinemic euglycemic clamp incorporating isotope-labeled tracers of glucose, palmitate, and urea. Substrate metabolism and skeletal muscle mitochondrial respiratory capacity were determined by indirect calorimetry and high-resolution respirometry, and body composition was assessed by bioelectrical impedance analysis. The primary outcome measure was change in insulin sensitivity. RESULTS Compared with placebo, metformin treatment lowered mean glycated hemoglobin levels (absolute mean difference, - 0.2%; 95% CI - 0.3 to 0.0; p = 0.03), reduced body weight (- 2.8 kg; 95% CI - 5.0 to - 0.6; p = 0.02), and increased fasting glucagon levels (3.2 pmol L-1; 95% CI 0.4 to 6.0; p = 0.03). No changes were observed in whole-body insulin sensitivity, endogenous glucose production, and peripheral glucose disposal or oxidation with metformin. Equally, resting energy expenditure, lipid and urea turnover, and skeletal muscle mitochondrial respiratory capacity remained unaltered. CONCLUSION Increased myocardial efficiency during metformin treatment is not mediated through improvements in insulin action in HF patients without diabetes. CLINICAL TRIAL REGISTRATION URL: https://clinicaltrials.gov . Unique identifier: NCT02810132. Date of registration: June 22, 2016.
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Pusceddu S, Vernieri C, Prinzi N, Torchio M, Coppa J, Antista M, Niger M, Milione M, Giacomelli L, Corti F, Prisciandaro M, Monteleone M, Colombo E, Di Bartolomeo M, de Braud F. The potential role of metformin in the treatment of patients with pancreatic neuroendocrine tumors: a review of preclinical to clinical evidence. Therap Adv Gastroenterol 2020; 13:1756284820927271. [PMID: 32821286 PMCID: PMC7406937 DOI: 10.1177/1756284820927271] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 04/15/2020] [Indexed: 02/04/2023] Open
Abstract
The incidence of pancreatic neuroendocrine tumors (panNETs) has increased worldwide in the last two decades. Given the indolent nature of these tumors, several patients are diagnosed with metastatic disease, which partially impairs the long-term efficacy of currently available treatments and reduces survival rates. The search for new therapeutic strategies for cancer patients has pushed towards the retrospective analysis of studies involving patients who concomitantly received other drugs together with standard anticancer agents. In this light, several retrospective analyses have shown that metformin use is associated with improved prognosis in patients with different tumor types treated with standard antitumor agents. Metformin, the cornerstone oral agent for the treatment of type 2 diabetes, plays a role in modulating glucose cell metabolism. Its potential ability to interfere with tumors may derive from the tight relationship between metabolic reprogramming in cancer cells and tumor progression. Indications for metformin use as an anticancer drug result from pre-clinical and clinical observations. In particular, metformin use in diabetic patients with advanced panNETs has been associated with better progression-free survival in patients treated with somatostatin analogues with or without metformin.
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Affiliation(s)
| | - Claudio Vernieri
- Fondazione IRCCS Istituto Nazionale dei Tumori, ENETS Center of Excellence, Milan, Italy The FIRC Institute of Molecular Oncology (IFOM), Milan, Italy
| | - Natalie Prinzi
- Fondazione IRCCS Istituto Nazionale dei Tumori, ENETS Center of Excellence, Milan, Italy
| | - Martina Torchio
- Fondazione IRCCS Istituto Nazionale dei Tumori, ENETS Center of Excellence, Milan, Italy
| | - Jorgelina Coppa
- Fondazione IRCCS Istituto Nazionale dei Tumori, ENETS Center of Excellence, Milan, Italy
| | - Maria Antista
- Fondazione IRCCS Istituto Nazionale dei Tumori, ENETS Center of Excellence, Milan, Italy
| | - Monica Niger
- Fondazione IRCCS Istituto Nazionale dei Tumori, ENETS Center of Excellence, Milan, Italy
| | - Massimo Milione
- Fondazione IRCCS Istituto Nazionale dei Tumori, ENETS Center of Excellence, Milan, Italy
| | - Luca Giacomelli
- Polistudium SRL (Milan, Italy) and Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy
| | - Francesca Corti
- Fondazione IRCCS Istituto Nazionale dei Tumori, ENETS Center of Excellence, Milan, Italy
| | - Michele Prisciandaro
- Fondazione IRCCS Istituto Nazionale dei Tumori, ENETS Center of Excellence, Milan, Italy
| | - Michela Monteleone
- Fondazione IRCCS Istituto Nazionale dei Tumori, ENETS Center of Excellence, Milan, Italy
| | - Elena Colombo
- Fondazione IRCCS Istituto Nazionale dei Tumori, ENETS Center of Excellence, Milan, Italy
| | - Maria Di Bartolomeo
- Fondazione IRCCS Istituto Nazionale dei Tumori, ENETS Center of Excellence, Milan, Italy
| | - Filppo de Braud
- Fondazione IRCCS Istituto Nazionale dei Tumori, ENETS Center of Excellence, Milan, Italy University of Milan, Milan, Italy
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Schernthaner G, Schernthaner GH. The right place for metformin today. Diabetes Res Clin Pract 2020; 159:107946. [PMID: 31778746 DOI: 10.1016/j.diabres.2019.107946] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Accepted: 11/22/2019] [Indexed: 02/06/2023]
Abstract
Metformin is the most widely used glucose lowering drug worldwide in the treatment of patients with type 2 diabetes, since we have experience with this drug for more than 60 years about the efficacy and safety. Metformin is very effective in HbA1c lowering associated with some weight loss, but does not increase risk for hypoglycemia. At the moment all guidelines in the world recommend to use metformin in monotherapy in patients with newly diagnosed diabetes or in combination with other antidiabetic drugs with documented CV (and renal) benefit in cardiovascular outcome trials (CVOT). Although a randomized placebo controlled CVOT with metformin is lacking, many observational studies in patients with coronary heart disease, heart failure and chronic kidney disease have demonstrated consistent beneficial effects. A recent metanalysis of 26 observational studies including 815 839 patients showed that metformin use was associated with a significantly lower rate of all-cause mortality (HR: 0.74; 95% CI: 0.68-0.81). Whether this very consistent reduction of all-cause mortality is related to the incidence/outcome of several cancers has still to be investigated. In the future early combination therapy of metformin e.g. with SGLT-2 inhibitors should be more often used.
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Affiliation(s)
- Guntram Schernthaner
- Rudolfstiftung Hospital & Medical University of Vienna, Department of Medicine II, Vienna, Austria; Medical University of Vienna, Department of Medicine II, Vienna, Austria
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11
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Khan RMM, Chua ZJY, Tan JC, Yang Y, Liao Z, Zhao Y. From Pre-Diabetes to Diabetes: Diagnosis, Treatments and Translational Research. MEDICINA (KAUNAS, LITHUANIA) 2019; 55:E546. [PMID: 31470636 PMCID: PMC6780236 DOI: 10.3390/medicina55090546] [Citation(s) in RCA: 145] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/29/2019] [Revised: 08/16/2019] [Accepted: 08/23/2019] [Indexed: 12/14/2022]
Abstract
Diabetes, a silent killer, is one of the most widely prevalent conditions of the present time. According to the 2017 International Diabetes Federation (IDF) statistics, the global prevalence of diabetes among the age group of 20-79 years is 8.8%. In addition, 1 in every 2 persons is unaware of the condition. This unawareness and ignorance lead to further complications. Pre-diabetes is the preceding condition of diabetes, and in most of the cases, this ultimately leads to the development of diabetes. Diabetes can be classified into three types, namely type 1 diabetes, type 2 diabetes mellitus (T2DM) and gestational diabetes. The diagnosis of both pre-diabetes and diabetes is based on glucose criteria; the common modalities used are fasting plasma glucose (FPG) test and oral glucose tolerance test (OGTT). A glucometer is commonly used by diabetic patients to measure blood glucose levels with fast and rather accurate measurements. A few of the more advanced and minimally invasive modalities include the glucose-sensing patch, SwEatch, eyeglass biosensor, breath analysis, etc. Despite a considerable amount of data being collected and analyzed regarding diabetes, the actual molecular mechanism of developing type 2 diabetes mellitus (T2DM) is still unknown. Both genetic and epigenetic factors are associated with T2DM. The complications of diabetes can predominantly be classified into two categories: microvascular and macrovascular. Retinopathy, nephropathy, and neuropathy are grouped under microvascular complications, whereas stroke, cardiovascular disease, and peripheral artery disease (PAD) belong to macrovascular complications. Unfortunately, until now, no complete cure for diabetes has been found. However, the treatment of pre-diabetes has shown significant success in preventing the further progression of diabetes. To prevent pre-diabetes from developing into T2DM, lifestyle intervention has been found to be very promising. Various aspects of diabetes, including the aforementioned topics, have been reviewed in this paper.
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Affiliation(s)
- Radia Marium Modhumi Khan
- School of Chemical and Biomedical Engineering, Nanyang Technological University, 62 Nanyang Drive, Singapore 637459, Singapore
| | - Zoey Jia Yu Chua
- School of Physical and Mathematical Sciences, Nanyang Technological University, 21 Nanyang Link, Singapore 637371, Singapore
| | - Jia Chi Tan
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore
| | - Yingying Yang
- Tongji University School of Medicine, Shanghai 201204, China
- Department of Medical Epidemiology and Biostatistics, Karolinska Institutet, 171 65 Solna, Sweden
| | - Zehuan Liao
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
- Department of Microbiology, Tumor, and Cell Biology (MTC), Karolinska Institutet, Biomedicum, Solnavägen 9, SE-17177 Stockholm, Sweden.
| | - Yan Zhao
- School of Biological Sciences, Nanyang Technological University, 60 Nanyang Drive, Singapore 637551, Singapore.
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12
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Eckstein ML, Williams DM, O'Neil LK, Hayes J, Stephens JW, Bracken RM. Physical exercise and non-insulin glucose-lowering therapies in the management of Type 2 diabetes mellitus: a clinical review. Diabet Med 2019; 36:349-358. [PMID: 30536728 DOI: 10.1111/dme.13865] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/19/2018] [Indexed: 01/05/2023]
Abstract
In the UK the National Institute of Health and Care Excellence (NICE) advocates intensive lifestyle programmes that attain the levels of daily physical activity set out by the Chief Medical Officer as a first-line strategy for improving the health of people at risk of developing diabetes or reducing the risk of development of Type 2 diabetes. For people with Type 2 diabetes, lifestyle measures complement pharmacological treatments that include both oral and injectable therapies. In line with this, NICE guidelines also support intensification of efforts to improve patient lifestyle along with these glucose-lowering therapies. There is a paucity of evidence, however, in the available published literature examining the association between glucose-lowering therapies and exercise metabolism. In the present review we explore the current knowledge with regard to the potential interactions of oral and non-insulin injectable therapies with physical activity in people at risk of, or who have, Type 2 diabetes, and present evidence that may inform healthcare professionals of the need to monitor patients more closely in their adaptation to both pharmacological therapy and physical activity.
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Affiliation(s)
- M L Eckstein
- Diabetes Research Group, Swansea University, Medical School, Swansea, UK
- Applied Sport, Technology, Exercise and Medicine Research Centre (A-STEM), College of Engineering, Swansea University, Swansea, UK
| | - D M Williams
- Diabetes Research Group, Swansea University, Medical School, Swansea, UK
- Department of Diabetes and Endocrinology, Morriston Hospital, Swansea, UK
| | - L K O'Neil
- Department of Diabetes and Endocrinology, Morriston Hospital, Swansea, UK
| | - J Hayes
- Diabetes Research Group, Swansea University, Medical School, Swansea, UK
- Department of Diabetes and Endocrinology, Morriston Hospital, Swansea, UK
| | - J W Stephens
- Diabetes Research Group, Swansea University, Medical School, Swansea, UK
- Department of Diabetes and Endocrinology, Morriston Hospital, Swansea, UK
| | - R M Bracken
- Diabetes Research Group, Swansea University, Medical School, Swansea, UK
- Applied Sport, Technology, Exercise and Medicine Research Centre (A-STEM), College of Engineering, Swansea University, Swansea, UK
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13
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Adeva-Andany MM, Rañal-Muíño E, Fernández-Fernández C, Pazos-García C, Vila-Altesor M. Metabolic Effects of Metformin in Humans. Curr Diabetes Rev 2019; 15:328-339. [PMID: 30306875 DOI: 10.2174/1573399814666181009125348] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/26/2018] [Revised: 09/26/2018] [Accepted: 10/02/2018] [Indexed: 12/25/2022]
Abstract
BACKGROUND Both insulin deficiency and insulin resistance due to glucagon secretion cause fasting and postprandial hyperglycemia in patients with diabetes. INTRODUCTION Metformin enhances insulin sensitivity, being used to prevent and treat diabetes, although its mechanism of action remains elusive. RESULTS Patients with diabetes fail to store glucose as hepatic glycogen via the direct pathway (glycogen synthesis from dietary glucose during the post-prandial period) and via the indirect pathway (glycogen synthesis from "de novo" synthesized glucose) owing to insulin deficiency and glucagoninduced insulin resistance. Depletion of the hepatic glycogen deposit activates gluconeogenesis to replenish the storage via the indirect pathway. Unlike healthy subjects, patients with diabetes experience glycogen cycling due to enhanced gluconeogenesis and failure to store glucose as glycogen. These defects raise hepatic glucose output causing both fasting and post-prandial hyperglycemia. Metformin reduces post-prandial plasma glucose, suggesting that the drug facilitates glucose storage as hepatic glycogen after meals. Replenishment of glycogen store attenuates the accelerated rate of gluconeogenesis and reduces both glycogen cycling and hepatic glucose output. Metformin also reduces fasting hyperglycemia due to declining hepatic glucose production. In addition, metformin reduces plasma insulin concentration in subjects with impaired glucose tolerance and diabetes and decreases the amount of insulin required for metabolic control in patients with diabetes, reflecting improvement of insulin activity. Accordingly, metformin preserves β-cell function in patients with type 2 diabetes. CONCLUSION Several mechanisms have been proposed to explain the metabolic effects of metformin, but evidence is not conclusive and the molecular basis of metformin action remains unknown.
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Affiliation(s)
- María M Adeva-Andany
- Internal Medicine Department, Hospital General Juan Cardona, c/ Pardo Bazan s/n, 15406 Ferrol, Spain
| | - Eva Rañal-Muíño
- Internal Medicine Department, Hospital General Juan Cardona, c/ Pardo Bazan s/n, 15406 Ferrol, Spain
| | | | - Cristina Pazos-García
- Internal Medicine Department, Hospital General Juan Cardona, c/ Pardo Bazan s/n, 15406 Ferrol, Spain
| | - Matilde Vila-Altesor
- Internal Medicine Department, Hospital General Juan Cardona, c/ Pardo Bazan s/n, 15406 Ferrol, Spain
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14
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Breining P, Jensen JB, Sundelin EI, Gormsen LC, Jakobsen S, Busk M, Rolighed L, Bross P, Fernandez-Guerra P, Markussen LK, Rasmussen NE, Hansen JB, Pedersen SB, Richelsen B, Jessen N. Metformin targets brown adipose tissue in vivo and reduces oxygen consumption in vitro. Diabetes Obes Metab 2018; 20:2264-2273. [PMID: 29752759 DOI: 10.1111/dom.13362] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/11/2018] [Revised: 05/01/2018] [Accepted: 05/09/2018] [Indexed: 01/11/2023]
Abstract
AIMS To test the hypothesis that brown adipose tissue (BAT) is a metformin target tissue by investigating in vivo uptake of [11 C]-metformin tracer in mice and studying in vitro effects of metformin on cultured human brown adipocytes. MATERIALS AND METHODS Tissue-specific uptake of metformin was assessed in mice by PET/CT imaging after injection of [11 C]-metformin. Human brown adipose tissue was obtained from elective neck surgery and metformin transporter expression levels in human and murine BAT were determined by qPCR. Oxygen consumption in metformin-treated human brown adipocyte cell models was assessed by Seahorse XF technology. RESULTS Injected [11 C]-metformin showed avid uptake in the murine interscapular BAT depot. Metformin exposure in BAT was similar to hepatic exposure. Non-specific inhibition of the organic cation transporter (OCT) protein by cimetidine administration eliminated BAT exposure to metformin, demonstrating OCT-mediated uptake. Gene expression profiles of OCTs in BAT revealed ample OCT3 expression in both human and mouse BAT. Incubation of a human brown adipocyte cell models with metformin reduced cellular oxygen consumption in a dose-dependent manner. CONCLUSION These results support BAT as a putative metformin target.
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Affiliation(s)
- Peter Breining
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Pharmacology, Aarhus University Hospital, Aarhus, Denmark
| | - Jonas B Jensen
- Department of Clinical Medicine, Research Laboratory for Biochemical Pathology, Aarhus University, Aarhus, Denmark
| | - Elias I Sundelin
- Department of Clinical Medicine, Research Laboratory for Biochemical Pathology, Aarhus University, Aarhus, Denmark
| | - Lars C Gormsen
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Steen Jakobsen
- Department of Nuclear Medicine and PET Centre, Aarhus University Hospital, Aarhus, Denmark
| | - Morten Busk
- Department of Experimental Clinical Oncology, Aarhus University Hospital, Aarhus, Denmark
| | - Lars Rolighed
- Department of Otorhinolaryngology and Department of Surgery P, Aarhus University Hospital, Aarhus, Denmark
| | - Peter Bross
- Department of Clinical Medicine, Research Unit for Molecular Medicine, Aarhus University and Aarhus University Hospital, Aarhus, Denmark
| | - Paula Fernandez-Guerra
- Department of Clinical Medicine, Research Unit for Molecular Medicine, Aarhus University and Aarhus University Hospital, Aarhus, Denmark
| | - Lasse K Markussen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
- Department of Biochemistry and Molecular Biology, University of Southern Denmark, Odense, Denmark
| | - Nanna E Rasmussen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Jacob B Hansen
- Department of Biology, University of Copenhagen, Copenhagen, Denmark
| | - Steen B Pedersen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Bjørn Richelsen
- Department of Endocrinology and Internal Medicine, Aarhus University Hospital, Aarhus, Denmark
| | - Niels Jessen
- Department of Clinical Pharmacology, Aarhus University Hospital, Aarhus, Denmark
- Department of Clinical Medicine, Research Laboratory for Biochemical Pathology, Aarhus University, Aarhus, Denmark
- Department of Biomedicine, Aarhus University, Aarhus, Denmark
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15
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Piera-Mardemootoo C, Lambert P, Faillie JL. Efficacy of metformin on glycemic control and weight in drug-naive type 2 diabetes mellitus patients: A systematic review and meta-analysis of placebo-controlled randomized trials. Therapie 2018; 76:647-656. [PMID: 29605144 DOI: 10.1016/j.therap.2018.01.006] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 12/04/2017] [Accepted: 01/23/2018] [Indexed: 01/10/2023]
Abstract
AIM OF THE STUDY Metformin is recommended as the first-line treatment of type 2 diabetes mellitus. Despite its common use, few studies have been conducted to precisely measure the efficacy of metformin versus placebo as a first-line treatment. This study aims to assess the precise effects of metformin monotherapy on glycemic control and weight in drug-naive patients with type 2 diabetes mellitus. METHODS Medline® and Cochrane databases were searched until March 19, 2016 to perform a systematic review and meta-analysis of placebo-controlled randomized trials evaluating metformin monotherapy in drug-naive patients with type 2 diabetes mellitus. Assessed outcomes include glycemic control (fasting plasma glucose, glycosated hemoglobin) and weight. RESULTS Overall, 16 studies (1140 patients) were selected. Compared to placebo, metformin monotherapy was associated with decreased glycosated hemoglobin by 0.95% at 3 months (95% CI: 0.50 to 1.39, I2=87%) and 1.32% at 6 months (95% CI: 1.01 to 1.62, I2=71%), and decreased fasting plasma glucose by 1.92mmol/L at 1 month (95% CI: 0.11 to 3.74, I2=88%), 1.79mmol/L at 3 months (95% CI: 0.92 to 2.66, I2=88%) and 2.14mmol/L at 6 months (95% CI: 1.17 to 3.12, I2=82%). No significant difference was demonstrated for the comparisons of weight due to relatively small number of studies retrieved from the literature resulting in insufficient statistical power. CONCLUSION This study provides the precise effects of metformin monotherapy regarding the decreases in fasting plasma glucose and glycosated hemoglobin that physician can expected in drug-naive patients with type 2 diabetes mellitus. No evidence was found for the effects on weight.
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Affiliation(s)
- Carole Piera-Mardemootoo
- Department of general medicine, Faculty of medicine, University of Montpellier, 34295 Montpellier, France
| | - Philippe Lambert
- Department of general medicine, Faculty of medicine, University of Montpellier, 34295 Montpellier, France
| | - Jean-Luc Faillie
- Department of medical pharmacology and toxicology, CHU Montpellier, 34295 Montpellier, France; Laboratory of biostatistics, epidemiology and public health (EA 2415), Faculty of medicine, University of Montpellier, 34295 Montpellier, France.
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16
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Cokorinos EC, Delmore J, Reyes AR, Albuquerque B, Kjøbsted R, Jørgensen NO, Tran JL, Jatkar A, Cialdea K, Esquejo RM, Meissen J, Calabrese MF, Cordes J, Moccia R, Tess D, Salatto CT, Coskran TM, Opsahl AC, Flynn D, Blatnik M, Li W, Kindt E, Foretz M, Viollet B, Ward J, Kurumbail RG, Kalgutkar AS, Wojtaszewski JFP, Cameron KO, Miller RA. Activation of Skeletal Muscle AMPK Promotes Glucose Disposal and Glucose Lowering in Non-human Primates and Mice. Cell Metab 2017; 25:1147-1159.e10. [PMID: 28467931 DOI: 10.1016/j.cmet.2017.04.010] [Citation(s) in RCA: 186] [Impact Index Per Article: 26.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2016] [Revised: 02/26/2017] [Accepted: 04/12/2017] [Indexed: 12/12/2022]
Abstract
The AMP-activated protein kinase (AMPK) is a potential therapeutic target for metabolic diseases based on its reported actions in the liver and skeletal muscle. We evaluated two distinct direct activators of AMPK: a non-selective activator of all AMPK complexes, PF-739, and an activator selective for AMPK β1-containing complexes, PF-249. In cells and animals, both compounds were effective at activating AMPK in hepatocytes, but only PF-739 was capable of activating AMPK in skeletal muscle. In diabetic mice, PF-739, but not PF-249, caused a rapid lowering of plasma glucose levels that was diminished in the absence of skeletal muscle, but not liver, AMPK heterotrimers and was the result of an increase in systemic glucose disposal with no impact on hepatic glucose production. Studies of PF-739 in cynomolgus monkeys confirmed translation of the glucose lowering and established activation of AMPK in skeletal muscle as a potential therapeutic approach to treat diabetic patients.
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Affiliation(s)
- Emily C Cokorinos
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
| | - Jake Delmore
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
| | - Allan R Reyes
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
| | - Bina Albuquerque
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
| | - Rasmus Kjøbsted
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen 1017, Denmark
| | - Nicolas O Jørgensen
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen 1017, Denmark
| | - Jean-Luc Tran
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
| | - Aditi Jatkar
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
| | - Katherine Cialdea
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
| | - Ryan M Esquejo
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
| | - John Meissen
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Inc., Groton, CT 06340, USA
| | - Matthew F Calabrese
- Worldwide Medicinal Chemistry, Pfizer Worldwide Research & Development, Pfizer Inc., Groton, CT 06340, USA
| | - Jason Cordes
- Drug Safety Research and Development, Pfizer Inc., Groton, CT 06340, USA
| | - Robert Moccia
- Computational Sciences, Pfizer Inc., Cambridge, MA 02139, USA
| | - David Tess
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Inc., Cambridge, MA 02139, USA
| | - Christopher T Salatto
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
| | - Timothy M Coskran
- Drug Safety Research and Development, Pfizer Inc., Groton, CT 06340, USA
| | - Alan C Opsahl
- Drug Safety Research and Development, Pfizer Inc., Groton, CT 06340, USA
| | - Declan Flynn
- Drug Safety Research and Development, Pfizer Inc., Groton, CT 06340, USA
| | - Matthew Blatnik
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Inc., Groton, CT 06340, USA
| | - Wenlin Li
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Inc., San Diego, CA 92121, USA
| | - Erick Kindt
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Inc., San Diego, CA 92121, USA
| | - Marc Foretz
- INSERM, U1016, Institut Cochin, Paris 75014, France; CNRS, UMR8104, Paris 75016, France; Université Paris Descartes, Sorbonne Paris Cité, Paris 75006, France
| | - Benoit Viollet
- INSERM, U1016, Institut Cochin, Paris 75014, France; CNRS, UMR8104, Paris 75016, France; Université Paris Descartes, Sorbonne Paris Cité, Paris 75006, France
| | - Jessica Ward
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02139, USA
| | - Ravi G Kurumbail
- Worldwide Medicinal Chemistry, Pfizer Worldwide Research & Development, Pfizer Inc., Groton, CT 06340, USA
| | - Amit S Kalgutkar
- Pharmacokinetics, Dynamics, and Metabolism, Pfizer Inc., Cambridge, MA 02139, USA
| | - Jørgen F P Wojtaszewski
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen 1017, Denmark
| | - Kimberly O Cameron
- Cardiovascular, Metabolic, and Endocrine Diseases Medicinal Chemistry, Pfizer Inc., Cambridge, MA 02139, USA
| | - Russell A Miller
- Cardiovascular, Metabolic, and Endocrine Diseases Research Unit, Pfizer Inc., Cambridge, MA 02139, USA.
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17
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Howell JJ, Hellberg K, Turner M, Talbott G, Kolar MJ, Ross DS, Hoxhaj G, Saghatelian A, Shaw RJ, Manning BD. Metformin Inhibits Hepatic mTORC1 Signaling via Dose-Dependent Mechanisms Involving AMPK and the TSC Complex. Cell Metab 2017; 25:463-471. [PMID: 28089566 PMCID: PMC5299044 DOI: 10.1016/j.cmet.2016.12.009] [Citation(s) in RCA: 267] [Impact Index Per Article: 38.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/25/2016] [Revised: 11/02/2016] [Accepted: 12/10/2016] [Indexed: 02/08/2023]
Abstract
Metformin is the most widely prescribed drug for the treatment of type 2 diabetes. However, knowledge of the full effects of metformin on biochemical pathways and processes in its primary target tissue, the liver, is limited. One established effect of metformin is to decrease cellular energy levels. The AMP-activated protein kinase (AMPK) and mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) are key regulators of metabolism that are respectively activated and inhibited in acute response to cellular energy depletion. Here we show that metformin robustly inhibits mTORC1 in mouse liver tissue and primary hepatocytes. Using mouse genetics, we find that at the lowest concentrations of metformin that inhibit hepatic mTORC1 signaling, this inhibition is dependent on AMPK and the tuberous sclerosis complex (TSC) protein complex (TSC complex). Finally, we show that metformin profoundly inhibits hepatocyte protein synthesis in a manner that is largely dependent on its ability to suppress mTORC1 signaling.
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Affiliation(s)
- Jessica J Howell
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Kristina Hellberg
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Marc Turner
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - George Talbott
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Matthew J Kolar
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Debbie S Ross
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Gerta Hoxhaj
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - Alan Saghatelian
- Clayton Foundation Laboratories for Peptide Biology, Salk Institute for Biological Studies, La Jolla, CA 92037, USA
| | - Reuben J Shaw
- Molecular and Cell Biology Laboratory, Salk Institute for Biological Studies, La Jolla, CA 92037, USA.
| | - Brendan D Manning
- Department of Genetics and Complex Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA.
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18
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Defronzo RA. Impaired glucose tolerance: do pharmacological therapies correct the underlying metabolic disturbance? ACTA ACUST UNITED AC 2016. [DOI: 10.1177/1474651403003001s0601] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Lifestyle intervention prevents or delays the conversion from impaired glucose tolerance (IGT) to type 2 diabetes. However, many subjects fail to achieve and/or maintain long-term weight loss and to follow a regular exercise regimen may require pharmacologic therapy. Insulin resistance in liver, muscle and fat, along with impaired beta-cell function, plays a central role in the pathogenesis of type 2 diabetes. Insulin sensitising drugs, including metformin and the thiazolidinediones, have significantly reduced the conversion rate of IGT to type 2 diabetes in subjects in several large, well designed clinical trials. Insulin-sensitising drugs are likely to play an important role in future strategies for diabetes prevention.
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Affiliation(s)
- Ralph A Defronzo
- Diabetes Division, University of Texas Health Science Center, 7703 Floyd Curl Drive, San Antonio, TX 78229, USA,
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19
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Bondar IA, Shabelnikova OY, Sokolova EA, Pyankova OV, Filipenko ML. Phenotypic and genetic characteristics of patients with type 2 diabetes with different responses to metformin therapy in Novosibirsk region. DIABETES MELLITUS 2016. [DOI: 10.14341/dm2004146-47] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Aim: The purpose of this study was to examine the phenotypic and genetic characteristics of patients with type 2 diabetes mellitus (T2DM) with different responses to treatment with metformin (MF) in the Novosibirsk region. Materials and methods: We examined 460 patients with T2DM in the Novosibirsk region. Patients were divided into groups according to their HbA1c level: patients who achieved the target HbA1c level during MF therapy (n = 209) and those who did not reach the target HbA1c level (n=251). Genotyping of ATM (rs11212617) was performed using polymerase chain reaction by TaqMan. Results: Patients who achieved the target HbA1c level during MF treatment (good response) were older (61. 1±9. 1 years vs. 57. 4±8. 4 years, p=0. 001), had later onset of diabetes (54. 6 ± 10. 1 years vs. 49. 2±8. 5 years, p = 0. 0001) and shorter duration of diabetes (6. 5±5. 9 years vs. 8. 2±6. 1 years, p=0. 03) compared with those who did not achieve the target HbA1c level. There was no statistically significant association between ATM rs11212617 and achieving the target HbA1c level among all patients [odds ratio (OR)=0. 94, 95% confidence interval = (0. 73–1. 23), p=0. 67] or those with MF monotherapy [OR=0. 90, (0. 65–1. 25), p=0. 54] or combination therapy [OR=1. 02, (0. 72–1. 43), p=0. 92]. There was an effect of age on response to MF therapy in all three groups (all patients: p=0. 001, MF monotherapy group: p=0. 04, combination therapy group: p=0. 0009). In the MF monotherapy group, low dose MF was associated with a good response (p=0. 03), and in the combination therapy group, males were more likely to have a good response (p=0. 003). Patients with genotype C/C or A/C for ATM (rs11212617) compared with those with genotype A/A were more likely to have high levels of triglycerides [2. 33 (1. 52–4. 2) mmol/l, 2. 09 (1. 35–3. 0) mmol/l and 1. 99 (1. 49–3. 21) mmol/l, respectively, p=0. 001], coronary heart disease (CHD) (13. 4%, 13. 4% and 9. 6%, respectively, p=0. 009) and myocardial infarction (7. 8%, 3. 2% and 4. 0%, respectively, p=0. 001). Conclusion: Patients with T2DM who had a good response to MF therapy were older, more likely to be male and had a later onset of T2DM. Genotype C/C for ATM rs11212617 was associated with high triglycerides, CHD and myocardial infarction. ATM rs11212617 was not associated with response to MF therapy in the Novosibirsk region.
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Saenz A, Fernandez-Esteban I, Mataix A, Ausejo Segura M, Roqué i Figuls M, Moher D. WITHDRAWN: Metformin monotherapy for type 2 diabetes mellitus. Cochrane Database Syst Rev 2015:CD002966. [PMID: 26421423 DOI: 10.1002/14651858.cd002966.pub4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Affiliation(s)
- Antonio Saenz
- Centro de Salud Pozuelo 1, INSALUD - Madrid, Emisora s/n, Pozuelo de Alarcón, Madrid, Spain, 28224
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Abstract
People with elevated, non-diabetic, levels of blood glucose are at risk of progressing to clinical type 2 diabetes and are commonly termed 'prediabetic'. The term prediabetes usually refers to high-normal fasting plasma glucose (impaired fasting glucose) and/or plasma glucose 2 h following a 75 g oral glucose tolerance test (impaired glucose tolerance). Current US guidelines consider high-normal HbA1c to also represent a prediabetic state. Individuals with prediabetic levels of dysglycaemia are already at elevated risk of damage to the microvasculature and macrovasculature, resembling the long-term complications of diabetes. Halting or reversing the progressive decline in insulin sensitivity and β-cell function holds the key to achieving prevention of type 2 diabetes in at-risk subjects. Lifestyle interventions aimed at inducing weight loss, pharmacologic treatments (metformin, thiazolidinediones, acarbose, basal insulin and drugs for weight loss) and bariatric surgery have all been shown to reduce the risk of progression to type 2 diabetes in prediabetic subjects. However, lifestyle interventions are difficult for patients to maintain and the weight loss achieved tends to be regained over time. Metformin enhances the action of insulin in liver and skeletal muscle, and its efficacy for delaying or preventing the onset of diabetes has been proven in large, well-designed, randomised trials, such as the Diabetes Prevention Program and other studies. Decades of clinical use have demonstrated that metformin is generally well-tolerated and safe. We have reviewed in detail the evidence base supporting the therapeutic use of metformin for diabetes prevention.
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Affiliation(s)
| | - Mike Gwilt
- />GT Communications, 4 Armoury Gardens, Shrewsbury, SY2 6PH UK
| | - Steven Hildemann
- />Merck KGaA, Darmstadt, Germany
- />Universitäts-Herzzentrum Freiburg–Bad Krozingen, Bad Krozingen, Germany
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Diurnal variation in skeletal muscle and liver glycogen in humans with normal health and Type 2 diabetes. Clin Sci (Lond) 2015; 128:707-13. [PMID: 25583442 DOI: 10.1042/cs20140681] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
In health, food carbohydrate is stored as glycogen in muscle and liver, preventing a deleterious rise in osmotically active plasma glucose after eating. Glycogen concentrations increase sequentially after each meal to peak in the evening, and fall to fasting levels thereafter. Skeletal muscle accounts for the larger part of this diurnal buffering capacity with liver also contributing. The effectiveness of this diurnal mechanism has not been previously studied in Type 2 diabetes. We have quantified the changes in muscle and liver glycogen concentration with 13C magnetic resonance spectroscopy at 3.0 T before and after three meals consumed at 4 h intervals. We studied 40 (25 males; 15 females) well-controlled Type 2 diabetes subjects on metformin only (HbA1c (glycated haemoglobin) 6.4±0.07% or 47±0.8 mmol/mol) and 14 (8 males; 6 females) glucose-tolerant controls matched for age, weight and body mass index (BMI). Muscle glycogen concentration increased by 17% after day-long eating in the control group (68.1±4.8 to 79.7±4.2 mmol/l; P=0.006), and this change inversely correlated with homoeostatic model assessment of insulin resistance [HOMA-IR] (r=-0.56; P=0.02). There was no change in muscle glycogen in the Type 2 diabetes group after day-long eating (68.3±2.6 to 67.1±2.0 mmol/mol; P=0.62). Liver glycogen rose similarly in normal control (325.9±25.0 to 388.1±30.3 mmol/l; P=0.005) and Type 2 diabetes groups (296.1±16.0 to 350.5±6.7 mmol/l; P<0.0001). In early Type 2 diabetes, the major physiological mechanism for skeletal muscle postprandial glycogen storage is completely inactive. This is directly related to insulin resistance, although liver glycogen storage is normal.
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Bohannon NJV. Individualized Treatment of Type 2 Diabetes Mellitus Using Noninsulin Agents: Clinical Considerations for the Primary Care Physician. Postgrad Med 2015; 124:95-108. [DOI: 10.3810/pgm.2012.07.2572] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
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Tan BK, Chen J, Hu J, Amar O, Mattu HS, Ramanjaneya M, Patel V, Lehnert H, Randeva HS. Circulatory changes of the novel adipokine adipolin/CTRP12 in response to metformin treatment and an oral glucose challenge in humans. Clin Endocrinol (Oxf) 2014; 81:841-6. [PMID: 24612181 DOI: 10.1111/cen.12438] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/06/2013] [Revised: 12/27/2013] [Accepted: 02/19/2014] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Adipolin/CTRP12 is a novel adipokine with anti-inflammatory and glucose-lowering properties in rodents. We sought to investigate the effects of metformin treatment (850 mg twice daily for 6 months) and a 2 h 75 g oral glucose tolerance test (OGTT) on serum adipolin concentrations in humans. DESIGN Cross-sectional study [PCOS (n = 83) and control (n = 39) subjects]. Serum adipolin was measured by ELISA. Metformin treatment (850 mg twice daily for 6 months) was offered to all women with PCOS, 34 women participated but 21 women completed 6 months of metformin therapy. Reasons for subjects not completing the study were nausea and gastrointestinal side effects (n = 4), pregnancies (n = 5), noncompliance (n = 2) and loss of contact (n = 2). RESULTS Metformin treatment (850 mg twice daily for 6 months) substantially increased serum adipolin concentrations (P < 0·05) in women with polycystic ovary syndrome (PCOS), a pro-inflammatory state associated with obesity, diabetes, dyslipidaemia and atherosclerosis. Furthermore, changes in waist-hip ratio, glucose, triglycerides, CRP and carotid intima media thickness showed significant negative associations with changes in adipolin levels (P < 0·05, P < 0·01); in multiple regression analyses, only changes in glucose were predictive of changes in adipolin levels (β = -0·570, P = 0·009). Serum adipolin decreased significantly in response to the OGTT in PCOS and control subjects at 90 min (P < 0·05) and 120 min (P < 0·01). CONCLUSIONS Adipolin and/or novel pharmacologic agents that increase adipolin's circulating concentrations might constitute a novel approach in the treatment of insulin resistant states.
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Affiliation(s)
- Bee K Tan
- Warwick Medical School, University of Warwick, Coventry, UK; Department of Obstetrics and Gynaecology, Birmingham Heartlands and Solihull Hospitals, Heart of England NHS Foundation Trust, Birmingham, UK
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Zhao Q, Hong D, Zheng D, Xiao Y, Wu B. Risk of diarrhea in patients with type 2 diabetes mellitus treated with sitagliptin: a meta-analysis of 30 randomized clinical trials. DRUG DESIGN DEVELOPMENT AND THERAPY 2014; 8:2283-94. [PMID: 25419118 PMCID: PMC4234286 DOI: 10.2147/dddt.s70945] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 01/25/2023]
Abstract
BACKGROUND Sitagliptin is an important drug used for diabetes treatment and is used as a monotherapy in diabetic patients. However, there are also reported cases of diarrhea with sitagliptin use. Unfortunately, data concerning the relationship of diarrhea with sitagliptin use in various conditions have yet to be identified. Therefore, the overall incidence and risk of diarrhea with sitagliptin use have not been well defined. METHODS We conducted searches on Embase, PubMed, and the Cochrane Library databases for relevant randomized controlled trials. Registered relevant trials at the clinical trials registration website were also searched. Statistical analyses were conducted to calculate the overall incidence, odds ratios, and 95% confidence intervals (CI) by using either random-effects or fixed-effect models according to the heterogeneity of the included studies. RESULTS A total of 8,891 subjects with diabetes from 30 randomized clinical trials were included in the meta-analysis. The overall incidence of sitagliptin-associated diarrhea was 4.48% (95% CI: 3.59%-5.58%). Compared with the controls, the use of sitagliptin was not associated with a significantly increased risk of diarrhea with an odds ratio of 1.10 (95% CI: 0.78%-1.55%; P=0.58). No evidence of publication bias was observed. CONCLUSION Our study has shown that there is no difference in diarrhea risk between sitagliptin and controlled therapies. Moreover, sitagliptin is not a medicine that potentially increases the risk of diabetic diarrhea. More studies are recommended to further investigate this association.
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Affiliation(s)
- Qingwei Zhao
- Department of Pharmacy, First Affiliated Hospital of College of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Dongsheng Hong
- Department of Pharmacy, First Affiliated Hospital of College of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Dongsheng Zheng
- Department of Pharmacy, First Affiliated Hospital of College of Medicine, Zhejiang University, Hangzhou, People's Republic of China
| | - Yao Xiao
- College of Pharmaceutical Science, Zhejiang Chinese Medical University, Hangzhou, People's Republic of China
| | - Baohua Wu
- Department of Pharmacy, First Affiliated Hospital of College of Medicine, Zhejiang University, Hangzhou, People's Republic of China
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Lin JT, Chen HM, Chiu CH, Liang YJ. AMP-activated protein kinase activators in diabetic ulcers: from animal studies to Phase II drugs under investigation. Expert Opin Investig Drugs 2014; 23:1253-65. [PMID: 24857754 DOI: 10.1517/13543784.2014.922951] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
INTRODUCTION Diagnosed cases of diabetes have gradually increased year by year, and research on diabetes mellitus (DM) has attracted greater attention from the medical profession. Diabetic ulcers present persistent pain and the risk of bacterial infection. However, no promising treatment methods have been found. As a regulator of cellular energy balance, 5' adenosine monophosphate-activated protein kinase (AMPK) has been suggested as a drug target for DM, including such drugs as metformin. AREAS COVERED This review summarizes the current research and clinical trials of AMPK activators on diabetic wound healing and diabetic ulcers. Furthermore, it discusses the feasibility of AMPK activators in the treatment of diabetic wounds. EXPERT OPINION Animal studies have demonstrated that AMPK activators are a potential treatment for diabetic ulcers. AMPK activators alleviate tissue inflammation and promote re-epithelialization in diabetic wounds. However, due to the complicated pathological mechanism of diabetic foot ulcers, AMPK activators should be combined with other approaches. The new strategies for combination therapy with AMPK activator may provide a therapeutic advantage for patients with diabetic ulcers.
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Affiliation(s)
- Jiun-Tsai Lin
- Energenesis Biomedical Co., Ltd. , New Taipei City , Taiwan
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Cicerchi C, Li N, Kratzer J, Garcia G, Roncal-Jimenez CA, Tanabe K, Hunter B, Rivard CJ, Sautin YY, Gaucher EA, Johnson RJ, Lanaspa MA. Uric acid-dependent inhibition of AMP kinase induces hepatic glucose production in diabetes and starvation: evolutionary implications of the uricase loss in hominids. FASEB J 2014; 28:3339-50. [PMID: 24755741 DOI: 10.1096/fj.13-243634] [Citation(s) in RCA: 129] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
Reduced AMP kinase (AMPK) activity has been shown to play a key deleterious role in increased hepatic gluconeogenesis in diabetes, but the mechanism whereby this occurs remains unclear. In this article, we document that another AMP-dependent enzyme, AMP deaminase (AMPD) is activated in the liver of diabetic mice, which parallels with a significant reduction in AMPK activity and a significant increase in intracellular glucose accumulation in human HepG2 cells. AMPD activation is induced by a reduction in intracellular phosphate levels, which is characteristic of insulin resistance and diabetic states. Increased gluconeogenesis is mediated by reduced TORC2 phosphorylation at Ser171 by AMPK in these cells, as well as by the up-regulation of the rate-limiting enzymes PEPCK and G6Pc. The mechanism whereby AMPD controls AMPK activation depends on the production of a specific AMP downstream metabolite through AMPD, uric acid. In this regard, humans have higher uric acid levels than most mammals due to a mutation in uricase, the enzyme involved in uric acid degradation in most mammals, that developed during a period of famine in Europe 1.5 × 10(7) yr ago. Here, working with resurrected ancestral uricases obtained from early hominids, we show that their expression on HepG2 cells is enough to blunt gluconeogenesis in parallel with an up-regulation of AMPK activity. These studies identify a key role AMPD and uric acid in mediating hepatic gluconeogenesis in the diabetic state, via a mechanism involving AMPK down-regulation and overexpression of PEPCK and G6Pc. The uricase mutation in the Miocene likely provided a survival advantage to help maintain glucose levels under conditions of near starvation, but today likely has a role in the pathogenesis of diabetes.
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Affiliation(s)
- Christina Cicerchi
- School of Medicine, University of Colorado Denver, Aurora, Colorado, USA
| | - Nanxing Li
- School of Medicine, University of Colorado Denver, Aurora, Colorado, USA
| | - James Kratzer
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA; and
| | - Gabriela Garcia
- School of Medicine, University of Colorado Denver, Aurora, Colorado, USA
| | | | - Katsuyuki Tanabe
- School of Medicine, University of Colorado Denver, Aurora, Colorado, USA
| | - Brandi Hunter
- School of Medicine, University of Colorado Denver, Aurora, Colorado, USA
| | | | - Yuri Y Sautin
- School of Medicine, University of Florida, Gainesville, Florida, USA
| | - Eric A Gaucher
- School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, USA; and
| | - Richard J Johnson
- School of Medicine, University of Colorado Denver, Aurora, Colorado, USA
| | - Miguel A Lanaspa
- School of Medicine, University of Colorado Denver, Aurora, Colorado, USA;
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Tan BK, Chen J, Adya R, Ramanjaneya M, Patel V, Randeva HS. Metformin increases the novel adipokine adipolin/CTRP12: role of the AMPK pathway. J Endocrinol 2013; 219:101-8. [PMID: 23946431 DOI: 10.1530/joe-13-0277] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Adipolin is a novel adipokine with anti-inflammatory and glucose-lowering properties. Lower levels of adipolin are found in obese and diabetic mice. Polycystic ovary syndrome (PCOS) is a pro-inflammatory state associated with obesity and diabetes. To date, there are no human studies on adipolin. Therefore, we measured serum (ELISA) and adipose tissue adipolin mRNA expression (RT-PCR) and protein concentrations (western blotting) in PCOS and control subjects. We also investigated the ex vivo effect of glucose and metformin on adipolin protein production in human subcutaneous adipose tissue explants. We report novel data that serum and subcutaneous adipose tissue adipolin mRNA expression and protein concentrations were significantly lower in women with PCOS compared with control subjects. Furthermore, Spearman's rank analysis showed that serum adipolin concentrations were significantly negatively correlated with BMI, waist-to-hip ratio, and glucose (P<0.05). However, when subjected to multiple regression analysis, none of these variables were predictive of serum adipolin concentrations (P>0.05). Also, subcutaneous adipose tissue adipolin mRNA expression and protein concentrations were only significantly negatively correlated with glucose (P<0.05). No significant correlations were found with omental adipose tissue adipolin mRNA expression and protein concentrations (P>0.05). Moreover, glucose profoundly reduced and metformin significantly increased adipolin protein production in human adipose tissue explants respectively. Importantly, metformin's effects appear to be via the AMP-activated protein kinase signaling pathway.
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Affiliation(s)
- Bee K Tan
- Warwick Medical School, University of Warwick, Coventry CV4 7AL, UK
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Mohamed EAH, Yam MF, Ang LF, Mohamed AJ, Asmawi MZ. Antidiabetic properties and mechanism of action of Orthosiphon stamineus Benth bioactive sub-fraction in streptozotocin-induced diabetic rats. J Acupunct Meridian Stud 2013; 6:31-40. [PMID: 23433053 DOI: 10.1016/j.jams.2013.01.005] [Citation(s) in RCA: 30] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2011] [Revised: 04/26/2012] [Accepted: 05/03/2012] [Indexed: 10/27/2022] Open
Abstract
Orthosiphon stamineus is a popular folk medicine widely used to treat many diseases including diabetes. Previous studies have shown that the sub-fraction of chloroform extract was able to inhibit the rise of blood glucose levels in a glucose tolerance test. This study was carried out to evaluate the chronic effect and possible mechanism of action of the bioactive chloroform sub-fraction of O. stamineus using streptozotocin-induced diabetic rats and in vitro methods. Administration of the chloroform extract sub-fraction 2 (Cƒ2-b) at a dose of 1 g/kg twice daily on diabetic rats for 14 days showed a significant lowering (p < 0.05) of the final blood glucose level compared to the pretreatment level. However, there were no significant differences in the plasma insulin levels post-treatment compared to the pretreatment levels for all doses of Cƒ2-b. Conversely, Cƒ2-b at a concentration of 2 mg/mL significantly increased (p < 0.001) the glucose uptake by the rat diaphragm muscle. The increase in glucose uptake was also shown when the muscle was incubated in a solution containing 1 IU/mL of insulin or 1 mg/mL of metformin. Furthermore, the effect of this sub-fraction on glucose absorption in the everted rat jejunum showed that Cƒ2-b at concentrations of 0.5 mg/mL, 1 mg/mL and, 2 mg/mL significantly reduced the glucose absorption of the jejunum (p < 0.05-0.001). Similarly, the absorption of glucose was also inhibited by 1 mg/mL and 2 mg/mL of metformin (p < 0.001). These results suggest that the effect of Cƒ2-b may be due to extra-pancreatic mechanisms. There was no evidence that the plant extract stimulated the release of insulin in order to lower the blood glucose level.
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Antidiabetic activities of oligosaccharides of Ophiopogonis japonicus in experimental type 2 diabetic rats. Int J Biol Macromol 2012; 51:749-55. [DOI: 10.1016/j.ijbiomac.2012.07.007] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/07/2012] [Revised: 06/07/2012] [Accepted: 07/08/2012] [Indexed: 11/20/2022]
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Gómez-Sámano MÁ, Gulias-Herrero A, Cuevas-Ramos D, Brau-Figueroa H, Mehta R, Vargas-Gutiérrez D, Meza-Arana CE, Nieves-Niebla JM, Vázquez-Hernández MO. Metformin and improvement of the hepatic insulin resistance index independent of anthropometric changes. Endocr Pract 2012; 18:8-16. [PMID: 21742607 DOI: 10.4158/ep11072.or] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
OBJECTIVE To determine the change in the hepatic insulin resistance index (HIRI) after metformin treatment. METHODS In this retrospective cohort study, Mexican mestizo patients with a body mass index (BMI) of 25 kg/m(2) or greater were evaluated. Participants were classified into 2 groups: patients who received metformin and patients who did not. Both groups were followed up for a median of 6 months (range, 4-10 months). The HIRI was calculated at baseline and at follow-up in both groups. We evaluated the independent effect of metformin on HIRI after adjustment for the difference in basal and final values (DELTA) of BMI, waist circumference, glucose, and insulin. RESULTS A total of 71 patients were enrolled (51 [72%] female). Forty-one patients received metformin and 30 patients did not. Mean age was 36.3 ± 12.2 years and mean BMI was 42.2 ± 10.7 kg/m(2). After metformin treatment, HIRI significantly decreased from 38 ± 10.7 to 34.7 ± 9.5 (P = .03). In contrast, the control group had a nonsignificant increase in HIRI (37.6 ± 11.7 to 40.0 ± 14.0, P = .22). Weight significantly decreased in both groups (group 1: 114.6 ± 33.8 kg to 107.6 ± 28.9 kg, P<.01; group 2: 104.8 ± 28.5 kg to 98.9 ± 26.0 kg, P<.01). After BMI adjustment, the total metformin dosage correlated negatively with HIRI (r = -0.36, P = .03). Using a linear regression model (F = 6.0, r2 = 0.37, P = .002) adjusted for DELTA BMI and DELTA waist circumference, the administration of metformin resulted in independent improvement in the HIRI level (standardized β = -0.29, t = -2.0, P = .04). CONCLUSIONS Metformin improves HIRI independently of anthropometric changes. In persons with elevated HIRI levels, metformin may be considered among the treatment options.
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Affiliation(s)
- Miguel Ángel Gómez-Sámano
- Department of Internal Medicine, Instituto Nacional de Ciencias Médicas y Nutrición Salvador Zubirán, Mexico City, Mexico
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Tan BK, Adya R, Chen J, Lehnert H, Sant Cassia LJ, Randeva HS. Metformin treatment exerts antiinvasive and antimetastatic effects in human endometrial carcinoma cells. J Clin Endocrinol Metab 2011; 96:808-16. [PMID: 21190977 DOI: 10.1210/jc.2010-1803] [Citation(s) in RCA: 96] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/08/2023]
Abstract
CONTEXT Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women associated with an increased risk of endometrial hyperplasia. We sought to study the effects of metformin treatment (widely used in the management of PCOS women) on human endometrial adenocarcinoma cells. OBJECTIVES To study the effects of metformin treatment on in vitro invasion and metastasis in human endometrial adenocarcinoma cells. Also, given the link between inflammation with endometrial cancer invasion and metastasis, we explored the roles of nuclear factor-κB (NF-κB), matrix metalloproteinases (MMPs) as well as v-akt murine thymoma viral oncogene homolog 1 (Akt) and extracellular signal-regulated kinases (Erk(1/2)) signaling pathways. DESIGN Sera were obtained from PCOS and control subjects. In vitro invasion were assessed in human endometrial cells (ECC-1 cells) by wound-healing motility and migration assays. NF-κB was studied by stably transfecting ECC-1 cells with a cis-reporter plasmid containing luciferase reporter gene linked to five repeats of NF-κB binding sites. The gelatinolytic activities of secreted MMP-2/9 in conditioned media were measured by gelatin zymography. Akt and Erk(1/2) phosphorylation were assessed by Western blotting. RESULTS In vitro invasion in ECC-1 cells was significantly attenuated by sera from PCOS women after 6 months of metformin treatment (850 mg twice daily) compared to matched controls (P < 0.01). These effects appear to be associated with NF-κB, MMP-2/9, as well as Akt and Erk(1/2) pathways that are known to be important regulators of inflammation, tumor invasion and metastasis. CONCLUSIONS Metformin, potentially, may serve as adjuvant treatment in the management of patients with endometrial cancer.
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Affiliation(s)
- Bee K Tan
- Endocrinology and Metabolism Group, Clinical Sciences Research Institute, Warwick Medical School, University of Warwick, Coventry CV4 7AL, United Kingdom.
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Tan BK, Chen J, Adya R, Randeva HS. Phosphoprotein enriched in diabetes gene product (Ped/pea-15) is increased in omental adipose tissue of women with the polycystic ovary syndrome: ex vivo regulation of ped/pea-15 by glucose, insulin and metformin. Diabetes Obes Metab 2011; 13:181-4. [PMID: 21199270 DOI: 10.1111/j.1463-1326.2010.01329.x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/18/2023]
Abstract
Polycystic ovary syndrome (PCOS), the commonest endocrine disorder in women, is characterized by an altered steroid milieu and is associated with insulin resistance and type 2 diabetes mellitus (T2DM). Phosphoprotein enriched in diabetes gene product (Ped/pea-15) regulates glucose metabolism and is increased in T2DM. Our novel data indicate that Ped/pea-15 mRNA expression and protein levels are significantly increased in omental adipose tissue (AT) from PCOS women compared to matched controls (p < 0.01); Ped/pea-15 levels in subcutaneous AT were not significantly different. Furthermore, Ped/pea-15 mRNA expression and protein levels were higher in omental compared to subcutaneous AT in PCOS subjects (p < 0.01); however, in control subjects, this was not significant. Glucose was predictive of omental AT Ped/pea-15 mRNA expression (p = 0.045). Importantly, glucose and insulin increased whereas metformin significantly decreased Ped/pea-15 levels in human omental AT explants. Our findings should serve to promote further research on Ped/pea-15 biology.
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Koiou E, Tziomalos K, Dinas K, Katsikis I, Kalaitzakis E, Delkos D, Kandaraki EA, Panidis D. The effect of weight loss and treatment with metformin on serum vaspin levels in women with polycystic ovary syndrome. Endocr J 2011; 58:237-46. [PMID: 21325745 DOI: 10.1507/endocrj.k10e-330] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Many patients with polycystic ovary syndrome (PCOS) have insulin resistance, obesity (mostly visceral) and glucose intolerance, conditions associated with abnormalities in the production of vaspin, a novel adipokine that appears to preserve insulin sensitivity and glucose tolerance. The aim of the study was to assess serum vaspin levels in PCOS and the effects on vaspin levels of metformin or of weight loss. We studied 79 patients with PCOS and 50 healthy female volunteers. Normal weight patients with PCOS (n=25) were treated with metformin 850 mg bid for 6 months. Overweight/obese patients with PCOS (n=54) were prescribed a normal-protein, energy-restricted diet for 6 months; half of them were also given orlistat 120 mg tid and the rest were given sibutramine 10 mg qd. At baseline and after 6 months, serum vaspin levels and anthropometric, metabolic and hormonal features of PCOS were determined. Overall, patients with PCOS had higher vaspin levels than controls (p=0.021). Normal weight patients with PCOS had higher vaspin levels than normal weight controls (p=0.043). Vaspin levels were non-significantly higher in overweight/obese patients with PCOS than in overweight/obese controls. In normal weight patients with PCOS, metformin reduced vaspin levels non-significantly. In overweight/obese patients with PCOS, diet plus orlistat or sibutramine did not affect vaspin levels. Vaspin levels were independently correlated with body mass index in women with PCOS (p=0.001) and with waist circumference in controls (p=0.015). In conclusion, serum vaspin levels are elevated in PCOS but neither a small weight loss nor metformin affect vaspin levels significantly.
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Affiliation(s)
- Ekaterini Koiou
- Division of Endocrinology and Human Reproduction, Second Department of Obstetrics and Gynecology, Aristotle University of Thessaloniki, Hippokration Hospital, Thessaloniki, Greece
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Tan BK, Adya R, Farhatullah S, Chen J, Lehnert H, Randeva HS. Metformin treatment may increase omentin-1 levels in women with polycystic ovary syndrome. Diabetes 2010; 59:3023-31. [PMID: 20852028 PMCID: PMC2992762 DOI: 10.2337/db10-0124] [Citation(s) in RCA: 92] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
Abstract
OBJECTIVE Polycystic ovary syndrome (PCOS) is associated with the metabolic syndrome. Decreased omentin-1 levels are associated with obesity and diabetes. To study the effects of metformin treatment on omentin-1 levels in PCOS subjects and effects of omentin-1 on in vitro migration and angiogenesis. RESEARCH DESIGN AND METHODS Serum omentin-1 was measured by ELISA. Angiogenesis was assessed by studying capillary tube formation in human microvascular endothelial cells (HMEC-1) on growth factor reduced Matrigel. Endothelial cell migration assay was performed in a modified Boyden chamber. Nuclear factor-κB (NF-κB) was studied by stably transfecting HMEC-1 cells with a cis-reporter plasmid containing luciferase reporter gene linked to five repeats of NF-κB binding sites. Akt phosphorylation was assessed by Western blotting. RESULTS Serum omentin-1 was significantly lower in PCOS women (P < 0.05). After 6 months of metformin treatment, there was a significant increase in serum omentin-1 (P < 0.01). Importantly, changes in hs-CRP were significantly negatively correlated with changes in serum omentin-1 (P = 0.036). In vitro migration and angiogenesis were significantly increased in serum from PCOS women (P < 0.01) compared with matched control subjects; these effects were significantly attenuated by metformin treatment (P < 0.01) plausibly through the regulation of omentin-1 levels via NF-κB and Akt pathways. CRP and VEGF induced in vitro migration, and angiogenesis was significantly decreased by omentin-1. CONCLUSIONS Increases in omentin-1 levels may play a role but are not sufficient to explain the decreased inflammatory and angiogenic effects of sera from metformin-treated PCOS women.
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Affiliation(s)
- Bee K Tan
- Edocrinology & Metabolism Group, Clinical Sciences Research Institute, Warwick Medical School, University of Warwick, Coventry, UK.
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Lin YC, Lin LY, Wang HF, Lin HD. Fasting plasma lactate concentrations in ambulatory elderly patients with type 2 diabetes receiving metformin therapy: a retrospective cross-sectional study. J Chin Med Assoc 2010; 73:617-22. [PMID: 21145508 DOI: 10.1016/s1726-4901(10)70135-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2010] [Accepted: 07/30/2010] [Indexed: 02/07/2023] Open
Abstract
BACKGROUND Metformin is a worldwide accepted biguanide antidiabetic agent, and its effectiveness and benefit have already been well established. Among the side effects of metformin, lactate acidosis is the most problematic because of a high mortality rate, which impedes its use in clinical practice, especially in elderly patients with type 2 diabetes. Aging is associated with a decreased renal function and increasing comorbidities, but few data are available regarding plasma lactate levels in this unique population. In this study, we assessed fasting plasma lactate levels in ambulatory, elderly Taiwanese patients with type 2 diabetes, who were taking the drug, metformin, to identify independent risk factors for hyperlactemia in this group. METHODS Sixty-six ambulatory type 2 diabetic patients, > 80 years of age (mean, 83.6 years; range, 80-90 years), receiving metformin therapy, were enrolled, from January 2005 to September 2009, in the Diabetes Case Management Program. A further 79 younger patients (also type 2 diabetics on metformin) served as controls (mean age, 59.9 years; range, 37-79 years). Fasting serum electrolytes, creatinine, bicarbonate, glycated hemoglobin, plasma glucose and lactate levels were determined. RESULTS Lactate levels did not differ between the elderly and control groups (13.2 +/- 5.2 mg/dL and 13.5 +/- 4.8 mg/dL, respectively). None of the patients fulfilled the lactic acidosis criteria. Patients in the elderly group had a significantly lower daily metformin dose, higher creatinine levels, and lower estimated creatinine clearance, compared with the control group (all p < 0.05). Estimated creatinine clearance was negatively associated with lactate levels in the elderly group (p < 0.05, r = -0.27), but not in the control group. Patients with fasting plasma glucose levels > 130 mg/dL had a 2.8-fold increased risk of developing hyperlactemia. CONCLUSION Plasma lactate levels in ambulatory elderly patients with type 2 diabetes receiving metformin therapy did not differ from those in a younger age group. Patients with fasting plasma glucose levels > 130 mg/dL had a 2.8-fold risk of developing hyperlactemia, but none of them developed lactate acidosis.
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Affiliation(s)
- Yi-Chun Lin
- Division of Endocrinology and Metabolism, Department of Medicine, Taipei Veterans General Hospital, and National Yang-Ming University, Taipei, Taiwan, R.O.C
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The anti-atherogenic aspect of metformin treatment in insulin resistant women with the polycystic ovary syndrome: role of the newly established pro-inflammatory adipokine Acute-phase Serum Amyloid A; evidence of an adipose tissue-monocyte axis. Atherosclerosis 2010; 216:402-8. [PMID: 20869715 DOI: 10.1016/j.atherosclerosis.2010.08.069] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/12/2010] [Revised: 08/13/2010] [Accepted: 08/17/2010] [Indexed: 11/20/2022]
Abstract
OBJECTIVE Acute-phase Serum Amyloid A (ASAA) is a novel pro-inflammatory adipokine, increased in obese, insulin resistant subjects. Polycystic ovary syndrome (PCOS) is associated with inflammation and atherosclerosis. We assessed sera, adipose tissue (AT) mRNA and protein levels of ASAA of PCOS women and matched controls. Ex vivo regulation of AT ASAA by d-glucose, effects of metformin treatment on circulating ASAA in PCOS subjects and effects of sera from normal and PCOS subjects (before and after metformin) on ASAA production (THP-1 macrophages) were also studied. METHODS AND RESULTS Circulating ASAA (ELISA), subcutaneous and omental AT ASAA mRNA (RT-PCR) and protein (western blotting) were significantly higher in PCOS women (P<0.05). In AT explants, glucose significantly increased ASAA production and secretion (P<0.05, P<0.01). Furthermore, ASAA production (THP-1 macrophages) was significantly greater by sera from PCOS women compared to controls (P<0.01). ASAA protein production was significantly decreased by sera from PCOS women following 6 months of metformin treatment (P<0.05). After 6 months of metformin treatment, there was a significant decrease in circulating ASAA (P<0.05). Importantly, changes in intima media thickness were predictive of changes in circulating ASAA (P=0.034). CONCLUSION Serum and AT ASAA are increased in PCOS women and are elevated by glucose. Metformin treatment decreases serum ASAA in these women. An adipose tissue-monocyte axis may be pivotal in the pathogenesis of inflammation and atherosclerosis. ASAA may be a valuable diagnostic marker in the management of dysmetabolic states including PCOS.
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Kane DA, Anderson EJ, Price JW, Woodlief TL, Lin CT, Bikman BT, Cortright RN, Neufer PD. Metformin selectively attenuates mitochondrial H2O2 emission without affecting respiratory capacity in skeletal muscle of obese rats. Free Radic Biol Med 2010; 49:1082-7. [PMID: 20600832 PMCID: PMC2921476 DOI: 10.1016/j.freeradbiomed.2010.06.022] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/01/2010] [Revised: 06/10/2010] [Accepted: 06/21/2010] [Indexed: 11/21/2022]
Abstract
Metformin is a widely prescribed drug for treatment of type 2 diabetes, although no cellular mechanism of action has been established. To determine whether in vivo metformin treatment alters mitochondrial function in skeletal muscle, respiratory O(2) flux and H(2)O(2) emission were measured in saponin-permeabilized myofibers from lean and obese (fa/fa) Zucker rats treated for 4 weeks with metformin. Succinate- and palmitoylcarnitine-supported respiration generated greater than twofold higher rates of H(2)O(2) emission in myofibers from untreated obese versus lean rats, indicative of an obesity-associated increased mitochondrial oxidant emitting potential. In conjunction with improved glycemic control, metformin treatment reduced H(2)O(2) emission in muscle from obese rats to rates near or below those observed in lean rats during both succinate- and palmitoylcarnitine-supported respiration. Surprisingly, metformin treatment did not affect basal or maximal rates of O(2) consumption in muscle from obese or lean rats. Ex vivo dose-response experiments revealed that metformin inhibits complex I-linked H(2)O(2) emission at a concentration approximately 2 orders of magnitude lower than that required to inhibit respiratory O(2) flux. These findings suggest that therapeutic concentrations of metformin normalize mitochondrial H(2)O(2) emission by blocking reverse electron flow without affecting forward electron flow or respiratory O(2) flux in skeletal muscle.
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MESH Headings
- Animals
- Diabetes Mellitus, Type 2/drug therapy
- Diabetes Mellitus, Type 2/physiopathology
- Electron Transport Complex I/metabolism
- Hydrogen Peroxide/metabolism
- Male
- Metformin/administration & dosage
- Metformin/therapeutic use
- Mitochondria, Muscle/drug effects
- Mitochondria, Muscle/metabolism
- Mitochondria, Muscle/pathology
- Muscle, Skeletal/drug effects
- Muscle, Skeletal/metabolism
- Muscle, Skeletal/pathology
- Myofibrils/drug effects
- Myofibrils/pathology
- Obesity
- Oxygen Consumption/drug effects
- Rats
- Rats, Sprague-Dawley
- Rats, Zucker
- Respiratory Rate/drug effects
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Affiliation(s)
- Daniel A. Kane
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Exercise and Sport Science, East Carolina University, Greenville, North Carolina
| | - Ethan J. Anderson
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Pharmacology & Toxicology, East Carolina University, Greenville, North Carolina
- Department of Cardiovascular Sciences, East Carolina University, Greenville, North Carolina
| | - Jesse W. Price
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Biology, East Carolina University, Greenville, North Carolina
| | - Tracey L. Woodlief
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Exercise and Sport Science, East Carolina University, Greenville, North Carolina
| | - Chien-Te Lin
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Exercise and Sport Science, East Carolina University, Greenville, North Carolina
| | - Benjamin T. Bikman
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Exercise and Sport Science, East Carolina University, Greenville, North Carolina
| | - Ronald N. Cortright
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Exercise and Sport Science, East Carolina University, Greenville, North Carolina
- Department of Physiology, East Carolina University, Greenville, North Carolina
| | - P. Darrell Neufer
- East Carolina Diabetes and Obesity Institute, East Carolina University, Greenville, North Carolina
- Department of Exercise and Sport Science, East Carolina University, Greenville, North Carolina
- Department of Physiology, East Carolina University, Greenville, North Carolina
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Spindler SR. Caloric restriction: from soup to nuts. Ageing Res Rev 2010; 9:324-53. [PMID: 19853062 DOI: 10.1016/j.arr.2009.10.003] [Citation(s) in RCA: 103] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2009] [Revised: 10/07/2009] [Accepted: 10/09/2009] [Indexed: 12/25/2022]
Abstract
Caloric restriction (CR), reduced protein, methionine, or tryptophan diets; and reduced insulin and/or IGFI intracellular signaling can extend mean and/or maximum lifespan and delay deleterious age-related physiological changes in animals. Mice and flies can shift readily between the control and CR physiological states, even at older ages. Many health benefits are induced by even brief periods of CR in flies, rodents, monkeys, and humans. In humans and nonhuman primates, CR produces most of the physiologic, hematologic, hormonal, and biochemical changes it produces in other animals. In primates, CR provides protection from type 2 diabetes, cardiovascular and cerebral vascular diseases, immunological decline, malignancy, hepatotoxicity, liver fibrosis and failure, sarcopenia, inflammation, and DNA damage. It also enhances muscle mitochondrial biogenesis, affords neuroprotection; and extends mean and maximum lifespan. CR rapidly induces antineoplastic effects in mice. Most claims of lifespan extension in rodents by drugs or nutrients are confounded by CR effects. Transcription factors and co-activators involved in the regulation of mitochondrial biogenesis and energy metabolism, including SirT1, PGC-1alpha, AMPK and TOR may be involved in the lifespan effects of CR. Paradoxically, low body weight in middle aged and elderly humans is associated with increased mortality. Thus, enhancement of human longevity may require pharmaceutical interventions.
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Salpeter SR, Greyber E, Pasternak GA, Salpeter EE. Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus. Cochrane Database Syst Rev 2010; 2010:CD002967. [PMID: 20393934 PMCID: PMC7138050 DOI: 10.1002/14651858.cd002967.pub4] [Citation(s) in RCA: 161] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
BACKGROUND Metformin is an oral anti-hyperglycemic agent that has been shown to reduce total mortality compared to other anti-hyperglycemic agents, in the treatment of type 2 diabetes mellitus. Metformin, however, is thought to increase the risk of lactic acidosis, and has been considered to be contraindicated in many chronic hypoxemic conditions that may be associated with lactic acidosis, such as cardiovascular, renal, hepatic and pulmonary disease, and advancing age. OBJECTIVES To assess the incidence of fatal and nonfatal lactic acidosis, and to evaluate blood lactate levels, for those on metformin treatment compared to placebo or non-metformin therapies. SEARCH STRATEGY A comprehensive search was performed of electronic databases to identify studies of metformin treatment. The search was augmented by scanning references of identified articles, and by contacting principal investigators. SELECTION CRITERIA Prospective trials and observational cohort studies in patients with type 2 diabetes of least one month duration were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy. DATA COLLECTION AND ANALYSIS The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for non-metformin treatments. The upper limit for the true incidence of cases was calculated using Poisson statistics. In a second analysis lactate levels were measured as a net change from baseline or as mean treatment values (basal and stimulated by food or exercise) for treatment and comparison groups. The pooled results were recorded as a weighted mean difference (WMD) in mmol/L, using the fixed-effect model for continuous data. MAIN RESULTS Pooled data from 347 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 70,490 patient-years of metformin use or in 55,451 patients-years in the non-metformin group. Using Poisson statistics the upper limit for the true incidence of lactic acidosis per 100,000 patient-years was 4.3 cases in the metformin group and 5.4 cases in the non-metformin group. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to non-metformin therapies. AUTHORS' CONCLUSIONS There is no evidence from prospective comparative trials or from observational cohort studies that metformin is associated with an increased risk of lactic acidosis, or with increased levels of lactate, compared to other anti-hyperglycemic treatments.
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Affiliation(s)
- Shelley R Salpeter
- Stanford University, and Santa Clara Valley Medical CenterMedicine2400 Moorpark Ave, Suite 118San JoseCAUSA95128
| | - Elizabeth Greyber
- Santa Clara Valley Medical CenterMedicine2400 Moorpark Ave, Suite 118San JoseCAUSA95128
| | - Gary A Pasternak
- Santa Clara Valley Medical CenterMedicine2400 Moorpark Ave, Suite 118San JoseCAUSA95128
| | - Edwin E Salpeter
- Cornell UniversityCenter for Radiophysics and Space Research612 Space Sciences BuildingIthacaNYUSA14853
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Minor RK, Allard JS, Younts CM, Ward TM, de Cabo R. Dietary interventions to extend life span and health span based on calorie restriction. J Gerontol A Biol Sci Med Sci 2010; 65:695-703. [PMID: 20371545 DOI: 10.1093/gerona/glq042] [Citation(s) in RCA: 78] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The societal impact of obesity, diabetes, and other metabolic disorders continues to rise despite increasing evidence of their negative long-term consequences on health span, longevity, and aging. Unfortunately, dietary management and exercise frequently fail as remedies, underscoring the need for the development of alternative interventions to successfully treat metabolic disorders and enhance life span and health span. Using calorie restriction (CR)-which is well known to improve both health and longevity in controlled studies-as their benchmark, gerontologists are coming closer to identifying dietary and pharmacological therapies that may be applicable to aging humans. This review covers some of the more promising interventions targeted to affect pathways implicated in the aging process as well as variations on classical CR that may be better suited to human adaptation.
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Affiliation(s)
- Robin K Minor
- Laboratory of Experimental Gerontology, National Institute on Aging, National Institutes of Health, 251 Bayview Boulevard, Suite 100, Room 9C-218, Baltimore, MD 21224, USA
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Salpeter SR, Greyber E, Pasternak GA, Salpeter Posthumous EE. Risk of fatal and nonfatal lactic acidosis with metformin use in type 2 diabetes mellitus. Cochrane Database Syst Rev 2010:CD002967. [PMID: 20091535 DOI: 10.1002/14651858.cd002967.pub3] [Citation(s) in RCA: 165] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
BACKGROUND Metformin is an oral anti-hyperglycemic agent that has been shown to reduce total mortality compared to other anti-hyperglycemic agents, in the treatment of type 2 diabetes mellitus. Metformin, however, is thought to increase the risk of lactic acidosis, and has been considered to be contraindicated in many chronic hypoxemic conditions that may be associated with lactic acidosis, such as cardiovascular, renal, hepatic and pulmonary disease, and advancing age. OBJECTIVES To assess the incidence of fatal and nonfatal lactic acidosis, and to evaluate blood lactate levels, for those on metformin treatment compared to placebo or non-metformin therapies. SEARCH STRATEGY A comprehensive search was performed of electronic databases to identify studies of metformin treatment. The search was augmented by scanning references of identified articles, and by contacting principal investigators. SELECTION CRITERIA Prospective trials and observational cohort studies in patients with type 2 diabetes of least one month duration were included if they evaluated metformin, alone or in combination with other treatments, compared to placebo or any other glucose-lowering therapy. DATA COLLECTION AND ANALYSIS The incidence of fatal and nonfatal lactic acidosis was recorded as cases per patient-years, for metformin treatment and for non-metformin treatments. The upper limit for the true incidence of cases was calculated using Poisson statistics. In a second analysis lactate levels were measured as a net change from baseline or as mean treatment values (basal and stimulated by food or exercise) for treatment and comparison groups. The pooled results were recorded as a weighted mean difference (WMD) in mmol/L, using the fixed-effect model for continuous data. MAIN RESULTS Pooled data from 347 comparative trials and cohort studies revealed no cases of fatal or nonfatal lactic acidosis in 70,490 patient-years of metformin use or in 55,451 patients-years in the non-metformin group. Using Poisson statistics the upper limit for the true incidence of lactic acidosis per 100,000 patient-years was 4.3 cases in the metformin group and 5.4 cases in the non-metformin group. There was no difference in lactate levels, either as mean treatment levels or as a net change from baseline, for metformin compared to non-metformin therapies. AUTHORS' CONCLUSIONS There is no evidence from prospective comparative trials or from observational cohort studies that metformin is associated with an increased risk of lactic acidosis, or with increased levels of lactate, compared to other anti-hyperglycemic treatments.
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Affiliation(s)
- Shelley R Salpeter
- Medicine, Stanford University, and Santa Clara Valley Medical Center, 2400 Moorpark Ave, Suite 118, San Jose, CA, USA, 95128
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Okamoto T, Kanemoto N, Ban T, Sudo T, Nagano K, Niki I. Establishment and characterization of a novel method for evaluating gluconeogenesis using hepatic cell lines, H4IIE and HepG2. Arch Biochem Biophys 2009; 491:46-52. [PMID: 19799852 DOI: 10.1016/j.abb.2009.09.015] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2009] [Revised: 09/24/2009] [Accepted: 09/24/2009] [Indexed: 02/03/2023]
Abstract
The liver gluconeogenic pathway is recognized as a target for treating diabetes mellitus. In this study, we attempted to establish a new method to evaluate gluconeogenesis using rat H4IIE hepatoma cells. High-density preculture and exposure to hypertonic solutions, which are known to upregulate the expression of gluconeogenic genes, enhanced glucose release (GR) promoted by gluconeogenic substrates (GS: 1mM pyruvate and 10mM lactate). Our method was also applicable to the human hepatoma HepG2 cells. Measurement of glycogen content in HepG2 cells revealed that GR was compensated by glycogenolysis in the basal state and was generated by gluconeogenesis in the presence of GS. The optimized conditions increased the expression of gluconeogenic genes in HepG2 cells. Insulin and metformin dose-dependently inhibited GR and 8-(4-chlorophenylthio)-cAMP (CPT-cAMP) increased it. These results suggest that the present method is useful to evaluate the effects of nutrients, hormones and hypoglycemic agents on hepatic gluconeogenesis.
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Affiliation(s)
- Takashi Okamoto
- First Institute of New Drug Discovery, Otsuka Pharmaceutical Co. Ltd., Kawauchi-cho, Tokushima, Japan
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Polakof S, Skiba-Cassy S, Panserat S. Glucose homeostasis is impaired by a paradoxical interaction between metformin and insulin in carnivorous rainbow trout. Am J Physiol Regul Integr Comp Physiol 2009; 297:R1769-76. [PMID: 19793955 DOI: 10.1152/ajpregu.00369.2009] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Utilizing rainbow trout (Oncorhynchus mykiss) as a known model of a "glucose-intolerant" and poor dietary glucose user, we assessed glucose utilization in fish chronically receiving two molecules able to improve glucose homeostasis: insulin and metformin. Our objectives were to assess the ability of rainbow trout to deal with a glucose load and to improve glucose utilization in fish receiving a chronic administration of insulin plus metformin treatments. Fish received (implanted miniosmotic pumps) saline, insulin, metformin, and insulin plus metformin solution for 4 days and then were subjected to a glucose challenge (intraperitoneal injection) to study glucose homeostasis, analyzing plasma glycemia, mRNA levels of glucose metabolism-related proteins, insulin signaling, and glycogen levels in liver and muscle. Control fish received a saline pump implantation and saline intraperitoneal injection. We found no evidence that the "glucose intolerance" in this species could be linked to any of the molecular markers of metabolism in the tissues analyzed. By contrast, very interestingly, we show for the first time, that metformin is not only unable to improve glucose homeostasis in trout, but, in fact, its counteracts the effects of insulin, creating an "insulin resistance," especially in the muscle. These results make trout an attractive original model to study both insulin and metformin effect on biological systems.
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Affiliation(s)
- S Polakof
- Institut National de la Recherche Agronomique, UMR 1067 Nutrition Aquaculture et Génomique, Saint-Pée-sur-Nivelle, France.
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Abstract
As the diabetic population has significant morbidity and mortality from cardiovascular disease (CVD), much of its medical care focuses on CVD prevention and treatment. Some medications used to treat hyperglycemia may have beneficial effects on CV outcomes, others may have negative effects, while still others seem to have no direct effect. Although past epidemiological studies have shown a relationship between glycated hemoglobin levels and CV events in patients with type 2 diabetes, recent large randomized clinical trials (ACCORD, ADVANCE, and VADT) lasting 3.5 to 5.6 years have found that intensive glycemic control either has no impact on CV outcomes or even worsens them. Results of the 10-year follow-up of the UKPDS suggest that tight glycemic control of younger, newly diagnosed patients with type 2 diabetes may have CV benefits many years later. Because the pathogenesis of atherosclerosis spans decades, it may be that beneficial effects of tight glycemic control on CV outcomes are mainly in younger patients without established macrovascular disease. There is an emerging notion that tight glycemic control may be beneficial in primary prevention of CVD in younger patients with diabetes, but may become deleterious in older patients with established or subclinical CVD. Thus, while tight control may lessen microvascular disease, it may increase the risk of hypoglycemia and possibly of adverse CV events. In each patient, the goals of glycemic control need to be individualized based on age, overall prognosis, presence of macrovascular disease, and risk of hypoglycemia.
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Okamoto T, Kanemoto N, Ohbuchi Y, Okano M, Fukui H, Sudo T. Characterization of STZ-Induced Type 2 Diabetes in Zucker Fatty Rats. Exp Anim 2008; 57:335-45. [PMID: 18633156 DOI: 10.1538/expanim.57.335] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022] Open
Abstract
The Zucker fatty (ZF) rat is a disease model of obesity and metabolic syndrome, such as hyperlipidemia and insulin resistance, resulting from hyperphagia owing to the loss of function of the leptin receptor, but it rarely develops hyperglycemia. We examined the effects of different doses of streptozotocin (STZ). A low dosage of STZ (30 mg/kg body weight, i.p.) elevated blood glucose levels in ZF rats up to 300 mg/dl within a week, and to nearly 500 mg/dl by 5 weeks after injection of STZ. Besides hyperglycemia, STZ-treated ZF (STZ-ZF) rats retained metabolic syndrome features such as hyperlipidemia and hyperinsulinemia. The stimulated insulin secretion in response to orally-loaded glucose disappeared completely in STZ-ZF rats. Although there were no significant differences in the morphology of pancreatic islets between vehicle-treated ZF (Cont-ZF) and STZ-ZF rats, the insulin content was markedly decreased in STZ-ZF rats. The hepatic gene expression for gluconeogenic enzymes was upregulated in STZ-ZF rats compared with Cont-ZF rats. Metformin lowered the blood glucose levels of STZ-ZF rats in a dose-dependent manner. These results suggest that STZ-ZF rats are useful for studies of T2DM and for the evaluation of the efficacy of anti-diabetic drugs.
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Affiliation(s)
- Takashi Okamoto
- First Institute of New Drug Discovery, Otsuka Pharmaceutical Co., Ltd., Tokushima, Japan
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Abstract
Metformin is now established as a first-line antidiabetic therapy for the management of type 2 diabetes. Its early use in treatment algorithms is supported by lack of weight gain, low risk of hypoglycaemia and its mode of action to counter insulin resistance. The drug's anti-atherosclerotic and cardioprotective effects have recently been confirmed in prospective and retrospective studies, and appear to reflect a collection of glucose-independent effects on the vascular endothelium, suppressant effects on glycation, oxidative stress and formation of adhesion molecules, stimulation of fibrinolysis and favourable effects on the lipid profile. Although avoidance of troublesome gastrointestinal tolerability issues requires careful dose titration, the risk of serious adverse events is considered low provided that contra-indications (especially with respect to renal function) are observed. As many of its actions go beyond glucose lowering, emerging evidence indicates potential benefits in other insulin-resistant states and possibly tumour suppression.
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Affiliation(s)
- John H B Scarpello
- Department of Diabetes and Endocrinology, University Hospital of North Staffordshire NHS Trust, Stoke-on-Trent, UK.
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48
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Tan BK, Heutling D, Chen J, Farhatullah S, Adya R, Keay SD, Kennedy CR, Lehnert H, Randeva HS. Metformin decreases the adipokine vaspin in overweight women with polycystic ovary syndrome concomitant with improvement in insulin sensitivity and a decrease in insulin resistance. Diabetes 2008; 57:1501-7. [PMID: 18375437 DOI: 10.2337/db08-0127] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Polycystic ovary syndrome (PCOS) is associated with insulin resistance and obesity. Vaspin (visceral adipose tissue-derived serine protease inhibitor) levels increase with hyperinsulinemia and obesity. Currently, no data exists on vaspin in PCOS women. We therefore assessed mRNA and protein levels of vaspin, including circulating vaspin, from subcutaneous and omental adipose tissue of PCOS women and matched control subjects. Ex vivo regulation of adipose tissue vaspin and the effects of metformin treatment on circulating vaspin levels in PCOS subjects were also studied. RESEARCH DESIGN AND METHODS Real-time RT-PCR and Western blotting were used to assess mRNA and protein expression of vaspin. Serum vaspin was quantified by enzyme-linked immunosorbent assay. The effects of d-glucose, insulin, and gonadal and adrenal steroids on adipose tissue vaspin were analyzed ex vivo. RESULTS There were significantly higher levels of circulating vaspin (P < 0.05), vaspin mRNA (P < 0.05), and protein (P < 0.05) in omental adipose tissue of PCOS women. Interestingly, in omental adipose tissue explants, glucose significantly increased vaspin protein levels and secretion into conditioned media (P < 0.001). Also, after 6 months of metformin treatment, there was a significant decrease in serum vaspin levels in PCOS women (P < 0.001). Furthermore, multivariate regression analysis revealed that following metformin therapy, changes in circulating glucose levels were predictive of changes in serum vaspin levels (P = 0.014). CONCLUSIONS We report, for the first time, elevated serum and omental adipose tissue levels of vaspin in overweight PCOS women and ex vivo regulation of vaspin, predominantly by glucose. More importantly, metformin treatment decreases serum vaspin levels, a novel observation.
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Affiliation(s)
- Bee K Tan
- Endocrinology & Metabolism Group, Clinical Sciences Research Institute, Warwick Medical School, University of Warwick, Coventry, UK
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49
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Brunani A, Caumo A, Graci S, Castagna G, Viberti G, Liuzzi A. Rosiglitazone is more effective than metformin in improving fasting indexes of glucose metabolism in severely obese, non-diabetic patients. Diabetes Obes Metab 2008; 10:460-7. [PMID: 17394563 DOI: 10.1111/j.1463-1326.2007.00728.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM In obese patients, the diet-induced weight loss markedly improves glucose tolerance with an increase in insulin sensitivity and a partial reduction of insulin secretion. The association with metformin treatment might potentiate the effect of diet alone. METHODS From patients admitted to our Nutritional Division for diet programme, we selected obese, non-diabetic, uncomplicated patients with age 18-65 years and body mass index 35-50 kg/m(2) and studied the effects of a 6-month pharmacological treatment with either metformin (850 mg twice daily) or rosiglitazone (4 mg twice daily) on possible changes in body weight, fat mass, glucose and lipids metabolism. RESULTS A significant weight loss and reduction of fat mass was demonstrated with metformin (-9.7 +/- 1.8 kg and -6.6 +/- 1.1 kg) and also with rosiglitazone (-11.0 +/- 1.9 kg and -7.2 +/- 1.8 kg), without fluid retention in either treatment group. Rosiglitazone administration induced a significant decrease in glucose concentration (4.7 +/- 0.1 vs. 4.4 +/- 0.1 mmol/l, p < 0.005) and insulin-circulating level (13.6 +/- 1.5 vs. 8.0 +/- 0.,7 microU/ml, p < 0.005), an increase in insulin sensitivity as measured by homeostatic model assessment (HOMA) of insulin sensitivity (68.9 +/- 8.8 vs. 109.9 +/- 10.3, p < 0.005) with a concomitant decrease in beta-cell function as measured by HOMA of beta-cell function (163.2 +/- 16.1 vs. 127.4 +/- 8.4, p < 0.005). In contrast, metformin did not produce any significant effect on blood glucose concentration, insulin level and HOMA2 indexes. No adverse events were registered with pharmacological treatments. CONCLUSION Our study shows that in severely obese, non-diabetic, hyperinsulinaemic patients undergoing a nutritional programme, rosiglitazone is more effective than metformin in producing favourable changes in fasting-based indexes of glucose metabolism, with a reduction of both insulin resistance and hyperinsulinaemia. In spite of previous studies reporting rosiglitazone-induced body weight gain, in our study the joint treatment with diet and rosiglitazone was accompanied by weight loss and fat mass reduction.
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Affiliation(s)
- A Brunani
- Department of Internal Medicine, Ospedale San Giuseppe, IRCCS, Istituto Auxologico Italiano, Verbania, Italy.
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50
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Gao H, Xiao W, Wang C, Zhang J, Yang Y, Yang J, Yang W, Hong T. The metabolic effects of once daily extended-release metformin in patients with type 2 diabetes: a multicentre study. Int J Clin Pract 2008; 62:695-700. [PMID: 18412932 DOI: 10.1111/j.1742-1241.2008.01733.x] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/28/2022] Open
Abstract
AIM To investigate the effects of extended-release metformin (MXR) compared with immediate-release metformin (MIR) on post-prandial glycaemic excursion, chronic glycaemia, lipid profiles, insulin resistance and islet function in type 2 diabetes. METHODS A randomised, open-labelled, positive-controlled multicentre study was conducted on 150 Chinese patients with type 2 diabetes. After 2 weeks of run-in period with MIR, 150 subjects were randomised into MXR group and MIR group. The patients in MXR group were assigned to take MXR 1500 mg once daily after dinner, while the patients in MIR group were assigned to continue MIR 500 mg thrice daily after meals for 12 weeks. Standard meal tests were carried out at baseline and at the end of this study. Plasma glucose, serum insulin, HbA1c and lipid profiles were measured. Homeostasis model assessment (HOMA) was used to evaluate insulin resistance index (HOMA-IR) and islet beta-cell function index (HOMA-B). RESULTS Either MIR or MXR modestly, but significantly decreased HbA1c levels and body mass index (BMI) after 12 weeks of treatment. However, there were no significant differences between two groups. The post-prandial glycaemia at 120 min after a standard meal in MXR group was higher than in MIR group (11.02 +/- 3.08 mmol/l vs. 9.74 +/- 2.61 mmol/l, p < 0.05). Moreover, no differences in the areas under curve of insulin release response, HOMA-B, HOMA-IR and lipid profiles were found within or between groups after 12 weeks of treatment. CONCLUSION The effects of once daily MXR on chronic glycaemia, BMI, lipid profiles, insulin resistance and islet function are comparable with that of thrice daily MIR in oriental population.
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Affiliation(s)
- H Gao
- Department of Endocrinology, Peking University Third Hospital, Beijing, China
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