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Ding D, Hou T, Wei M, Wu JX, Chen L. The inhibition mechanism of the SUR2A-containing K ATP channel by a regulatory helix. Nat Commun 2023; 14:3608. [PMID: 37330603 PMCID: PMC10276813 DOI: 10.1038/s41467-023-39379-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 06/10/2023] [Indexed: 06/19/2023] Open
Abstract
KATP channels are metabolic sensors for intracellular ATP/ADP ratios, play essential roles in many physiological processes, and are implicated in a spectrum of pathological conditions. SUR2A-containing KATP channels differ from other subtypes in their sensitivity to Mg-ADP activation. However, the underlying structural mechanism remains poorly understood. Here we present a series of cryo-EM structures of SUR2A in the presence of different combinations of Mg-nucleotides and the allosteric inhibitor repaglinide. These structures uncover regulatory helix (R helix) on the NBD1-TMD2 linker, which wedges between NBD1 and NBD2. R helix stabilizes SUR2A in the NBD-separated conformation to inhibit channel activation. The competitive binding of Mg-ADP with Mg-ATP to NBD2 mobilizes the R helix to relieve such inhibition, allowing channel activation. The structures of SUR2B in similar conditions suggest that the C-terminal 42 residues of SUR2B enhance the structural dynamics of NBD2 and facilitate the dissociation of the R helix and the binding of Mg-ADP to NBD2, promoting NBD dimerization and subsequent channel activation.
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Affiliation(s)
- Dian Ding
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China
| | - Tianyi Hou
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, 100871, Beijing, China
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China
| | - Miao Wei
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China
| | - Jing-Xiang Wu
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China
| | - Lei Chen
- State Key Laboratory of Membrane Biology, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, 100871, Beijing, China.
- Peking-Tsinghua Center for Life Sciences, Peking University, 100871, Beijing, China.
- National Biomedical Imaging Center, Peking University, 100871, Beijing, China.
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2
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Cao R, Tian H, Zhang Y, Liu G, Xu H, Rao G, Tian Y, Fu X. Signaling pathways and intervention for therapy of type 2 diabetes mellitus. MedComm (Beijing) 2023; 4:e283. [PMID: 37303813 PMCID: PMC10248034 DOI: 10.1002/mco2.283] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2023] [Revised: 04/18/2023] [Accepted: 04/27/2023] [Indexed: 06/13/2023] Open
Abstract
Type 2 diabetes mellitus (T2DM) represents one of the fastest growing epidemic metabolic disorders worldwide and is a strong contributor for a broad range of comorbidities, including vascular, visual, neurological, kidney, and liver diseases. Moreover, recent data suggest a mutual interplay between T2DM and Corona Virus Disease 2019 (COVID-19). T2DM is characterized by insulin resistance (IR) and pancreatic β cell dysfunction. Pioneering discoveries throughout the past few decades have established notable links between signaling pathways and T2DM pathogenesis and therapy. Importantly, a number of signaling pathways substantially control the advancement of core pathological changes in T2DM, including IR and β cell dysfunction, as well as additional pathogenic disturbances. Accordingly, an improved understanding of these signaling pathways sheds light on tractable targets and strategies for developing and repurposing critical therapies to treat T2DM and its complications. In this review, we provide a brief overview of the history of T2DM and signaling pathways, and offer a systematic update on the role and mechanism of key signaling pathways underlying the onset, development, and progression of T2DM. In this content, we also summarize current therapeutic drugs/agents associated with signaling pathways for the treatment of T2DM and its complications, and discuss some implications and directions to the future of this field.
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Affiliation(s)
- Rong Cao
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
| | - Huimin Tian
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China Medical School, West China HospitalSichuan UniversityChengduSichuanChina
| | - Yu Zhang
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China Medical School, West China HospitalSichuan UniversityChengduSichuanChina
| | - Geng Liu
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
| | - Haixia Xu
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
| | - Guocheng Rao
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China Medical School, West China HospitalSichuan UniversityChengduSichuanChina
| | - Yan Tian
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
| | - Xianghui Fu
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China HospitalSichuan University and Collaborative Innovation Center of BiotherapyChengduSichuanChina
- Department of Endocrinology and MetabolismState Key Laboratory of Biotherapy and Cancer CenterWest China Medical School, West China HospitalSichuan UniversityChengduSichuanChina
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3
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DeMarsilis A, Reddy N, Boutari C, Filippaios A, Sternthal E, Katsiki N, Mantzoros C. Pharmacotherapy of type 2 diabetes: An update and future directions. Metabolism 2022; 137:155332. [PMID: 36240884 DOI: 10.1016/j.metabol.2022.155332] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Revised: 10/07/2022] [Accepted: 10/07/2022] [Indexed: 11/06/2022]
Abstract
Type 2 diabetes (T2D) is a widely prevalent disease with substantial economic and social impact for which multiple conventional and novel pharmacotherapies are currently available; however, the landscape of T2D treatment is constantly changing as new therapies emerge and the understanding of currently available agents deepens. This review aims to provide an updated summary of the pharmacotherapeutic approach to T2D. Each class of agents is presented by mechanism of action, details of administration, side effect profile, cost, and use in certain populations including heart failure, non-alcoholic fatty liver disease, obesity, chronic kidney disease, and older individuals. We also review targets of novel therapeutic T2D agent development. Finally, we outline an up-to-date treatment approach that starts with identification of an individualized goal for glycemic control then selection, initiation, and further intensification of a personalized therapeutic plan for T2D.
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Affiliation(s)
- Antea DeMarsilis
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA
| | - Niyoti Reddy
- Department of Medicine, School of Medicine, Boston University, Boston, USA
| | - Chrysoula Boutari
- Second Propedeutic Department of Internal Medicine, Hippocration Hospital, Medical School, Aristotle University of Thessaloniki, Thessaloniki, Greece
| | - Andreas Filippaios
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA
| | - Elliot Sternthal
- Section of Endocrinology, VA Boston Healthcare System, Harvard Medical School, Boston, MA 02115, USA
| | - Niki Katsiki
- Department of Nutritional Sciences and Dietetics, International Hellenic University, Sindos, Greece; School of Medicine, European University Cyprus, Nicosia, Cyprus.
| | - Christos Mantzoros
- Department of Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, USA; Section of Endocrinology, VA Boston Healthcare System, Harvard Medical School, Boston, MA 02115, USA
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4
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Wang M, Wu JX, Chen L. Structural Insights Into the High Selectivity of the Anti-Diabetic Drug Mitiglinide. Front Pharmacol 2022; 13:929684. [PMID: 35847046 PMCID: PMC9279661 DOI: 10.3389/fphar.2022.929684] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Accepted: 05/25/2022] [Indexed: 11/13/2022] Open
Abstract
Mitiglinide is a highly selective fast-acting anti-diabetic drug that induces insulin secretion by inhibiting pancreatic KATP channels. However, how mitiglinide binds KATP channels remains unknown. Here, we show the cryo-EM structure of the SUR1 subunit complexed with mitiglinide. The structure reveals that mitiglinide binds inside the common insulin secretagogue-binding site of SUR1, which is surrounded by TM7, TM8, TM16, and TM17. Mitiglinide locks SUR1 in the NBD-separated inward-facing conformation. The detailed structural analysis of the mitiglinide-binding site uncovers the molecular basis of its high selectivity.
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Affiliation(s)
- Mengmeng Wang
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- National Biomedical Imaging Center, Peking University, Beijing, China
| | - Jing-Xiang Wu
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing, China
- National Biomedical Imaging Center, Peking University, Beijing, China
| | - Lei Chen
- State Key Laboratory of Membrane Biology, Beijing Key Laboratory of Cardiometabolic Molecular Medicine, College of Future Technology, Institute of Molecular Medicine, Peking University, Beijing, China
- Peking-Tsinghua Center for Life Sciences, Peking University, Beijing, China
- Academy for Advanced Interdisciplinary Studies, Peking University, Beijing, China
- National Biomedical Imaging Center, Peking University, Beijing, China
- *Correspondence: Lei Chen,
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Lv W, Wang X, Xu Q, Lu W. Mechanisms and Characteristics of Sulfonylureas and Glinides. Curr Top Med Chem 2020; 20:37-56. [PMID: 31884929 DOI: 10.2174/1568026620666191224141617] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2019] [Revised: 08/30/2019] [Accepted: 09/22/2019] [Indexed: 12/25/2022]
Abstract
BACKGROUND Type 2 diabetes mellitus is a complex progressive endocrine disease characterized by hyperglycemia and life-threatening complications. It is the most common disorder of pancreatic cell function that causes insulin deficiency. Sulfonylurea is a class of oral hypoglycemic drugs. Over the past half century, these drugs, together with the subsequent non-sulfonylureas (glinides), have been the main oral drugs for insulin secretion. OBJECTIVE Through in-depth study, the medical profession considers it as an important drug for improving blood sugar control. METHODS The mechanism, characteristics, efficacy and side effects of sulfonylureas and glinides were reviewed in detail. RESULTS Sulfonylureas and glinides not only stimulated the release of insulin from pancreatic cells, but also had many extrapanular hypoglycemic effect, such as reducing the clearance rate of insulin in liver, reducing the secretion of glucagon, and enhancing the sensitivity of peripheral tissues to insulin in type 2 diabetes mellitus. CONCLUSION Sulfonylureas and glinides are effective first-line drugs for the treatment of diabetes mellitus. Although they have the risk of hypoglycemia, weight gain and cardiovascular disease, their clinical practicability and safety can be guaranteed as long as they are reasonably used.
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Affiliation(s)
- Wei Lv
- School of Materials Science and Engineering, Shanghai University, Shanghai, China.,Shanghai Huayi Resins Co., Ltd., Shanghai, China
| | - Xianqing Wang
- Charles Institute of Dermatology, University College Dublin, Dublin D04 V1W8, Ireland
| | - Qian Xu
- Charles Institute of Dermatology, University College Dublin, Dublin D04 V1W8, Ireland
| | - Wencong Lu
- School of Materials Science and Engineering, Shanghai University, Shanghai, China
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La Fuente JM, Fernández A, Pepe-Cardoso AJ, Martínez-Salamanca JI, Louro N, Angulo J. L-cysteine/hydrogen sulfide pathway induces cGMP-dependent relaxation of corpus cavernosum and penile arteries from patients with erectile dysfunction and improves arterial vasodilation induced by PDE5 inhibition. Eur J Pharmacol 2019; 863:172675. [PMID: 31542487 DOI: 10.1016/j.ejphar.2019.172675] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/23/2019] [Revised: 09/10/2019] [Accepted: 09/18/2019] [Indexed: 02/06/2023]
Abstract
The aim was to evaluate and characterize H2S-induced relaxation of human corpus cavernosum (HCC) and penile resistance arteries (HPRA) from patients with erectile dysfunction (ED). HCC and HPRA were obtained from men with ED at the time of penile prosthesis insertion. H2S-mediated relaxations were evaluated by exposing these tissues to the stable analogue, NaHS, and to the precursor of H2S, L-cysteine (CYS). The effects of NaHS and CYS were also evaluated on cGMP accumulation in HCC and on acetylcholine- and sildenafil-mediated relaxations in HCC and HPRA. NaHS consistently relaxed HPRA and HCC and more potently than human prostate and bladder. NaHS-induced relaxations in HCC and HPRA were unaffected by the ATP-sensitive K+-channel blocker, glibenclamide or the NO synthase inhibitor, L-NAME, slightly reduced by the Ca2+-activated K+-channel blocker, tetraethylammonium, and markedly inhibited by the soluble guanylyl cyclase inhibitor, ODQ. NaHS caused a cGMP increase in HCC that was inhibited by ODQ. CYS produced relaxations of HCC and HPRA that were sensitive to ODQ and to inhibition of the H2S synthesizing enzymes, cystathionine γ-lyase (CSE) and cystathionine β-synthase (CBS). CYS also increased cGMP in HCC. In contrast to NaHS, CYS-induced relaxations were prevented by endothelium removal in HPRA. Only in HPRA, treatment with CYS (30 μM) potentiated acetylcholine- and sildenafil-induced relaxations. This effect was prevented by CSE/CBS inhibition and by removing the endothelium. Exogenous and endogenous H2S relaxes HCC and HPRA from ED patients through cGMP accumulation and potentiates vasodilatory capacity of PDE5 inhibition, supporting the therapeutic potential of modulating H2S pathway.
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Affiliation(s)
| | - Argentina Fernández
- Servicio de Histología-Investigación, Unidad de Investigación Traslacional en Cardiología (UFV-IRYCIS), Hospital Universitario Ramón y Cajal, Madrid, Spain
| | | | | | - Nuno Louro
- Serviço de Urologia, Hospital Santo Antonio, Porto, Portugal
| | - Javier Angulo
- Servicio de Histología-Investigación, Unidad de Investigación Traslacional en Cardiología (UFV-IRYCIS), Hospital Universitario Ramón y Cajal, Madrid, Spain.
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Bell DSH, Goncalves E. Heart failure in the patient with diabetes: Epidemiology, aetiology, prognosis, therapy and the effect of glucose-lowering medications. Diabetes Obes Metab 2019; 21:1277-1290. [PMID: 30724013 DOI: 10.1111/dom.13652] [Citation(s) in RCA: 52] [Impact Index Per Article: 10.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/25/2018] [Revised: 01/29/2019] [Accepted: 02/03/2019] [Indexed: 12/24/2022]
Abstract
In people with type 2 diabetes the frequency of heart failure (HF) is increased and mortality from HF is higher than with non-diabetic HF. The increased frequency of HF is attributable to the cardiotoxic tetrad of ischaemic heart disease, left ventricular hypertrophy, diabetic cardiomyopathy and an extracellular volume expansion resistant to atrial natriuretic peptides. Activation of the renin-angiotensin-aldosterone system and sympathetic nervous systems results in cardiac remodelling, which worsens cardiac function. Reversal of remodelling can be achieved, and cardiac function improved in people with HF with reduced ejection fraction (HFrEF) by treatment with angiotensin-converting enzyme inhibitors and β-blockers. However, with HF with preserved ejection fraction (HFpEF), only therapy for the underlying risk factors helps. Blockers of mineralocorticoid receptors may be beneficial in both HFrEF and HFpEF. Glucose-lowering drugs can have a negative effect (insulin, sulphonylureas, dipeptidyl peptidase-4 inhibitors and thiazolidinediones), a neutral effect (α-glucosidase inhibitors and glucagon-like peptide-1 receptor agonists) or a positive effect (sodium-glucose co-transporter-2 inhibitors and metformin).
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8
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Caine BA, Bronzato M, Popelier PLA. Experiment stands corrected: accurate prediction of the aqueous p K a values of sulfonamide drugs using equilibrium bond lengths. Chem Sci 2019; 10:6368-6381. [PMID: 31341593 PMCID: PMC6601425 DOI: 10.1039/c9sc01818b] [Citation(s) in RCA: 17] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/12/2019] [Accepted: 05/19/2019] [Indexed: 12/14/2022] Open
Abstract
We show here for the first time that strongly correlated linear relationships exist between equilibrium bond lengths of the sulfonamide group and aqueous pKa values.
We show here for the first time that strongly correlated linear relationships exist between equilibrium bond lengths of the sulfonamide group and aqueous pKa values. Models are constructed for three variants of the SO2NHR group: primary benzene sulfonamide derivatives (e.g. diuretic drugs furosemide and hydrochlorothiazide), N-phenyl substituted 4-amino-N-phenylbenzenesulfonamide analogues (e.g. the sulfa antibiotic sulfadiazine) and phenylsulfonylureas (e.g. insulin secretagogue, glimepiride). In the context of these compounds, we present solutions to some of the more complex challenges in pKa prediction: (i) prediction for multiprotic compounds, (ii) predicting macroscopic values for compounds that tautomerize, and (iii) quantum chemical pKa prediction for compounds with more than 50 atoms. Using bond lengths as a powerful descriptor of ionization feasibility, we also identify that literature values for drug compounds celecoxib, glimepiride and glipizide are inaccurate. Our newly measured experimental values match our initial predictions to within 0.26 pKa units, whereas previous values were found to deviate by up to 1.68 pKa units. For glimepiride, our corrected value denotes a percentage of ionization at intracellular pH, which is only now in excellent agreement with its known therapeutic efficacy. We propose that linear relationships between bond lengths and pKa should emerge for any set of congeners, thus providing a powerful method of pKa prediction in instances where pKa data exist for close congeners, thereby obviating the need for thermodynamic cycles.
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Affiliation(s)
- Beth A Caine
- Manchester Institute of Biotechnology (MIB) , 131 Princess Street , Manchester M1 7DN , UK . .,School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK
| | | | - Paul L A Popelier
- Manchester Institute of Biotechnology (MIB) , 131 Princess Street , Manchester M1 7DN , UK . .,School of Chemistry , University of Manchester , Oxford Road , Manchester M13 9PL , UK
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Sikimic J, McMillen TS, Bleile C, Dastvan F, Quast U, Krippeit-Drews P, Drews G, Bryan J. ATP binding without hydrolysis switches sulfonylurea receptor 1 (SUR1) to outward-facing conformations that activate K ATP channels. J Biol Chem 2018; 294:3707-3719. [PMID: 30587573 DOI: 10.1074/jbc.ra118.005236] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2018] [Revised: 12/19/2018] [Indexed: 11/06/2022] Open
Abstract
Neuroendocrine-type ATP-sensitive K+ (KATP) channels are metabolite sensors coupling membrane potential with metabolism, thereby linking insulin secretion to plasma glucose levels. They are octameric complexes, (SUR1/Kir6.2)4, comprising sulfonylurea receptor 1 (SUR1 or ABCC8) and a K+-selective inward rectifier (Kir6.2 or KCNJ11). Interactions between nucleotide-, agonist-, and antagonist-binding sites affect channel activity allosterically. Although it is hypothesized that opening these channels requires SUR1-mediated MgATP hydrolysis, we show here that ATP binding to SUR1, without hydrolysis, opens channels when nucleotide antagonism on Kir6.2 is minimized and SUR1 mutants with increased ATP affinities are used. We found that ATP binding is sufficient to switch SUR1 alone between inward- or outward-facing conformations with low or high dissociation constant, KD , values for the conformation-sensitive channel antagonist [3H]glibenclamide ([3H]GBM), indicating that ATP can act as a pure agonist. Assembly with Kir6.2 reduced SUR1's KD for [3H]GBM. This reduction required the Kir N terminus (KNtp), consistent with KNtp occupying a "transport cavity," thus positioning it to link ATP-induced SUR1 conformational changes to channel gating. Moreover, ATP/GBM site coupling was constrained in WT SUR1/WT Kir6.2 channels; ATP-bound channels had a lower KD for [3H]GBM than ATP-bound SUR1. This constraint was largely eliminated by the Q1179R neonatal diabetes-associated mutation in helix 15, suggesting that a "swapped" helix pair, 15 and 16, is part of a structural pathway connecting the ATP/GBM sites. Our results suggest that ATP binding to SUR1 biases KATP channels toward open states, consistent with SUR1 variants with lower KD values causing neonatal diabetes, whereas increased KD values cause congenital hyperinsulinism.
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Affiliation(s)
- Jelena Sikimic
- From the Institute of Pharmacy, Department of Pharmacology, University of Tübingen, D-72076 Tübingen, Germany and
| | - Timothy S McMillen
- Pacific Northwest Diabetes Research Institute, Seattle, Washington 98122, and
| | - Cita Bleile
- From the Institute of Pharmacy, Department of Pharmacology, University of Tübingen, D-72076 Tübingen, Germany and
| | - Frank Dastvan
- Pacific Northwest Diabetes Research Institute, Seattle, Washington 98122, and
| | - Ulrich Quast
- Department of Experimental and Clinical Pharmacology and Toxicology, Eberhard Karls University Hospitals and Clinics, D-72074 Tübingen, Germany
| | - Peter Krippeit-Drews
- From the Institute of Pharmacy, Department of Pharmacology, University of Tübingen, D-72076 Tübingen, Germany and
| | - Gisela Drews
- From the Institute of Pharmacy, Department of Pharmacology, University of Tübingen, D-72076 Tübingen, Germany and
| | - Joseph Bryan
- Pacific Northwest Diabetes Research Institute, Seattle, Washington 98122, and
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Wang LC, Fang FS, Gong YP, Yang G, Li CL. Characteristics of repaglinide and its mechanism of action on insulin secretion in patients with newly diagnosed type-2 diabetes mellitus. Medicine (Baltimore) 2018; 97:e12476. [PMID: 30235745 PMCID: PMC6160250 DOI: 10.1097/md.0000000000012476] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/26/2022] Open
Abstract
This study aims to compare the effect of repaglinide and metformin among Chinese patients with newly diagnosed diabetes, and explore the possible mechanisms by which repaglinide alters insulin secretion.Sixty subjects with glycated hemoglobin (HbA1c) < 10.0% were randomly selected to receive repaglinide or metformin monotherapy for 15 weeks. Blood glucose levels, glycemic variability, β-cell function, and first-phase insulin secretion were compared between these 2 groups at baseline and at 15 weeks. Mouse insulinoma (MIN-6) cells were divided into 3 groups: low glucose, high glucose, and repaglinide 50 nm groups. Cells and cell culture mediums were collected at different timepoints. The expression of pericentrin (PCNT), F-actin, and insulin were tested with immunofluorescence and enzyme-linked immunosorbent assay.All glycemic parameters and variability indexes significantly decreased from baseline to 15 weeks, while no significant difference was found between these 2 groups at baseline or at 15 weeks. Furthermore, there was no significant difference found in fasting insulin and postprandial insulin at baseline and at 15 weeks, while homeostasis model assessment β significantly increased. The first-phase glucose and insulin secretion of the intravenous glucose tolerance test improved in both groups, especially in the repaglinide group. Insulin, PCNT, and F-actin expression in MIN-6 cells decreased after 15 minutes of stimulation with repaglinide, while no difference was observed at 2, 6, and 12 hours. The insulin levels of the cell medium in the repaglinide group remained significantly higher at all timepoints.This study manifests that repaglinide has a noninferiority effect on the glycemic parameters of Chinese patients with newly diagnosed diabetes, when compared with metformin. The PCNT-F-actin pathway plays an important role in the repaglinide regulation process of on-demand insulin secretion.
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Affiliation(s)
- Liang-Chen Wang
- Department of Geriatric Endocrinology, Chinese PLA General Hospital
- National Clinical Research Center for Geriatic Diseases
- Department of Endocrinology, Air Force General Hospital, PLA, Beijing, China
| | - Fu-Sheng Fang
- Department of Geriatric Endocrinology, Chinese PLA General Hospital
- National Clinical Research Center for Geriatic Diseases
| | - Yan-Ping Gong
- Department of Geriatric Endocrinology, Chinese PLA General Hospital
- National Clinical Research Center for Geriatic Diseases
| | - Guang Yang
- Department of Geriatric Endocrinology, Chinese PLA General Hospital
- National Clinical Research Center for Geriatic Diseases
| | - Chun-Lin Li
- Department of Geriatric Endocrinology, Chinese PLA General Hospital
- National Clinical Research Center for Geriatic Diseases
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11
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Takahashi H, Hidaka S, Seki C, Yokoi N, Seino S. Characteristics of repaglinide effects on insulin secretion. Eur J Pharmacol 2018; 828:52-59. [PMID: 29555503 DOI: 10.1016/j.ejphar.2018.03.025] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2017] [Revised: 03/13/2018] [Accepted: 03/14/2018] [Indexed: 12/25/2022]
Abstract
The dynamics of insulin secretion stimulated by repaglinide, a glinide, and the combinatorial effects of repaglinide and incretin were investigated. At 4.4 mM glucose, repaglinide induced insulin secretion with a gradually increasing first phase, showing different dynamics from that induced by glimepiride, a sulfonylurea. In the presence of glucagon-like peptide-1 (GLP-1), insulin secretion by repaglinide was augmented significantly but to lesser extent and showed different dynamics from that by glimepiride. At 4.4 mM glucose, the intracellular Ca2+ level was gradually increased by repaglinide alone or repaglinide plus GLP-1, which differs from the Ca2+ dynamics by glimepiride alone or glimepiride plus GLP-1, suggesting that the difference in Ca2+ dynamics contributes to the difference in the dynamics of insulin secretion. At a higher concentration (8.8 mM) of glucose, the dynamics of insulin secretion stimulated by repaglinide was similar to that by glimepiride. Combination of repaglinide and GLP-1 significantly augmented insulin secretion, the amount of which was comparable to that by the combination of glimepiride and GLP-1. The Ca2+ dynamics was similar for repaglinide and glimepiride at 8.8 mM glucose. Our data indicate that repaglinide has characteristic properties in its effects on the dynamics of insulin secretion and intracellular Ca2+ and that the combination of repaglinide and GLP-1 stimulates insulin secretion more effectively than the combination of glimepiride and GLP-1 at a high concentration of glucose, providing a basis for its use in clinical settings.
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Affiliation(s)
- Harumi Takahashi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; Kansai Electric Power Medical Research Institute, 1-5-6 Minatojimaminamimachi, Chuo-ku, Kobe 650-0047, Japan.
| | - Shihomi Hidaka
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Chihiro Seki
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan
| | - Norihide Yokoi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; Kansai Electric Power Medical Research Institute, 1-5-6 Minatojimaminamimachi, Chuo-ku, Kobe 650-0047, Japan
| | - Susumu Seino
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, 7-5-1 Kusunoki-cho, Chuo-ku, Kobe 650-0017, Japan; Kansai Electric Power Medical Research Institute, 1-5-6 Minatojimaminamimachi, Chuo-ku, Kobe 650-0047, Japan.
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12
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Kasturi SP, Surarapu S, Uppalanchi S, Dwivedi S, Yogeeswari P, Sigalapalli DK, Bathini NB, Ethiraj KS, Anireddy JS. Synthesis, molecular modeling and evaluation of α-glucosidase inhibition activity of 3,4-dihydroxy piperidines. Eur J Med Chem 2018. [DOI: 10.1016/j.ejmech.2018.02.072] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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13
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Wu HC, Horng CT, Tsai SC, Lee YL, Hsu SC, Tsai YJ, Tsai FJ, Chiang JH, Kuo DH, Yang JS. Relaxant and vasoprotective effects of ginger extracts on porcine coronary arteries. Int J Mol Med 2018; 41:2420-2428. [PMID: 29328426 DOI: 10.3892/ijmm.2018.3380] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2016] [Accepted: 11/30/2017] [Indexed: 11/06/2022] Open
Abstract
Ginger (Zingiber officinale Roscoe) is a popular Chinese herbal medicine, which is considered to warm the stomach and dispel cold in traditional Chinese medicine. Ginger is widely used to treat stomach disorders, and it has been reported to exhibit antithrombotic activity via the inhibition of platelet aggregation and thromboxane B2 production in vitro. Cardiovascular disease is associated with the aberrant functioning of the heart and circulatory system; the relatively narrow vessels of the circulation are commonly affected and blocked by atherosclerosis, which may result in angina or heart attack. Numerous drugs and medicines are used to treat myocardial infarction; however, they are often associated with numerous side effects. Therefore, it is important to identify substitutive drugs with no unbearable side effects. In the present study, the relaxant effects of ginger crude extract (GCE) were determined on porcine coronary arteries. The DPPH radical scavenging assay, lucigenin‑enhanced chemiluminescence assay and western blot analysis were used to individually detect antioxidant assay of ginger extraction or superoxide anion produced by endothelial cells and molecular signaling. The results indicated that GCE induced relaxation of porcine coronary arteries in an endothelium‑dependent manner. GCE increased vasoprotection via the suppression of nitric oxide synthase and cyclooxygenase. In addition, GCE possessed antioxidant ability, as determined using 1,1‑diphenyl‑2‑picrylhydrazyl and lucigenin‑enhanced chemiluminescence assays. Taken together, the present study demonstrated that GCE exerts marked vasoprotective effects and free radical‑scavenging activities in porcine coronary arteries.
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Affiliation(s)
- Hsing-Chen Wu
- Department of Nutrition, Kaohsiung Armed Forces General Hospital, Kaohsiung 80284, Taiwan, R.O.C
| | - Chi-Ting Horng
- Medical Education Center, Kaohsiung Armed Forces General Hospital, Kaohsiung 80284, Taiwan, R.O.C
| | - Shih-Chang Tsai
- Department of Biological Science and Technology, China Medical University, Taichung 40402, Taiwan, R.O.C
| | - You-Li Lee
- Department of Nutrition, Kaohsiung Armed Forces General Hospital, Kaohsiung 80284, Taiwan, R.O.C
| | - Shou-Cheng Hsu
- Department of Pharmacy and Master Program, Tajen University, Pingtung 90741, Taiwan, R.O.C
| | - Yi-Jen Tsai
- Department of Pharmacy and Master Program, Tajen University, Pingtung 90741, Taiwan, R.O.C
| | - Fuu-Jen Tsai
- School of Post‑Baccalaureate Chinese Medicine, China Medical University, Taichung 40402, Taiwan, R.O.C
| | - Jo-Hua Chiang
- Department of Nursing, Chung‑Jen Junior College of Nursing, Health Sciences and Management, Chiayi 62241, Taiwan, R.O.C
| | - Daih-Huang Kuo
- Department of Pharmacy and Master Program, Tajen University, Pingtung 90741, Taiwan, R.O.C
| | - Jai-Sing Yang
- Department of Medical Research, China Medical University Hospital, China Medical University, Taichung 40447, Taiwan, R.O.C
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14
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Avogaro A. Keeping the right track in the treatment of patients with type 2 diabetes. Eur J Heart Fail 2017; 20:52-54. [PMID: 29251397 DOI: 10.1002/ejhf.1118] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/08/2017] [Accepted: 11/22/2017] [Indexed: 12/28/2022] Open
Affiliation(s)
- Angelo Avogaro
- Unit of Metabolic Diseases, Department of Medicine, University of Padova, Padova, Italy
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15
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Seino S, Sugawara K, Yokoi N, Takahashi H. β-Cell signalling and insulin secretagogues: A path for improved diabetes therapy. Diabetes Obes Metab 2017; 19 Suppl 1:22-29. [PMID: 28880474 DOI: 10.1111/dom.12995] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/29/2017] [Revised: 04/24/2017] [Accepted: 04/27/2017] [Indexed: 12/26/2022]
Abstract
Insulin secretagogues including sulfonylureas, glinides and incretin-related drugs such as dipeptidyl peptidase 4 (DPP-4) inhibitors and glucagon-like peptide-1 receptor agonists are widely used for treatment of type 2 diabetes. In addition, glucokinase activators and G-protein-coupled receptor 40 (GPR40) agonists also have been developed, although the drugs are not clinically usable. These different drugs exert their effects on insulin secretion by different mechanisms. Recent advances in β-cell signalling studies have not only deepened our understanding of insulin secretion but also revealed novel mechanisms of insulin secretagogues. Clarification of the signalling mechanisms of the insulin secretagogues will contribute to improved drug therapy for diabetes.
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Affiliation(s)
- Susumu Seino
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Kenji Sugawara
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
- Division of Diabetes and Endocrinology, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Norihide Yokoi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
| | - Harumi Takahashi
- Division of Molecular and Metabolic Medicine, Kobe University Graduate School of Medicine, Kobe, Japan
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16
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Cervantes Gracia K, Llanas-Cornejo D, Husi H. CVD and Oxidative Stress. J Clin Med 2017; 6:E22. [PMID: 28230726 PMCID: PMC5332926 DOI: 10.3390/jcm6020022] [Citation(s) in RCA: 182] [Impact Index Per Article: 26.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2016] [Revised: 02/12/2017] [Accepted: 02/14/2017] [Indexed: 12/12/2022] Open
Abstract
Nowadays, it is known that oxidative stress plays at least two roles within the cell, the generation of cellular damage and the involvement in several signaling pathways in its balanced normal state. So far, a substantial amount of time and effort has been expended in the search for a clear link between cardiovascular disease (CVD) and the effects of oxidative stress. Here, we present an overview of the different sources and types of reactive oxygen species in CVD, highlight the relationship between CVD and oxidative stress and discuss the most prominent molecules that play an important role in CVD pathophysiology. Details are given regarding common pharmacological treatments used for cardiovascular distress and how some of them are acting upon ROS-related pathways and molecules. Novel therapies, recently proposed ROS biomarkers, as well as future challenges in the field are addressed. It is apparent that the search for a better understanding of how ROS are contributing to the pathophysiology of CVD is far from over, and new approaches and more suitable biomarkers are needed for the latter to be accomplished.
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Affiliation(s)
- Karla Cervantes Gracia
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, BHF Glasgow Cardiovascular Research Centre, 126 University Place, Glasgow G12 8TA, UK.
| | - Daniel Llanas-Cornejo
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, BHF Glasgow Cardiovascular Research Centre, 126 University Place, Glasgow G12 8TA, UK.
| | - Holger Husi
- Institute of Cardiovascular and Medical Sciences, University of Glasgow, BHF Glasgow Cardiovascular Research Centre, 126 University Place, Glasgow G12 8TA, UK.
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17
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Katsumata Y, Nelson PT, Ellingson SR, Fardo DW. Gene-based association study of genes linked to hippocampal sclerosis of aging neuropathology: GRN, TMEM106B, ABCC9, and KCNMB2. Neurobiol Aging 2017; 53:193.e17-193.e25. [PMID: 28131462 DOI: 10.1016/j.neurobiolaging.2017.01.003] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2016] [Revised: 12/29/2016] [Accepted: 01/03/2017] [Indexed: 12/12/2022]
Abstract
Hippocampal sclerosis of aging (HS-Aging) is a common neurodegenerative condition associated with dementia. To learn more about genetic risk of HS-Aging pathology, we tested gene-based associations of the GRN, TMEM106B, ABCC9, and KCNMB2 genes, which were reported to be associated with HS-Aging pathology in previous studies. Genetic data were obtained from the Alzheimer's Disease Genetics Consortium, linked to autopsy-derived neuropathological outcomes from the National Alzheimer's Coordinating Center. Of the 3251 subjects included in the study, 271 (8.3%) were identified as an HS-Aging case. The significant gene-based association between the ABCC9 gene and HS-Aging appeared to be driven by a region in which a significant haplotype-based association was found. We tested this haplotype as an expression quantitative trait locus using 2 different public-access brain gene expression databases. The HS-Aging pathology protective ABCC9 haplotype was associated with decreased ABCC9 expression, indicating a possible toxic gain of function.
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Affiliation(s)
- Yuriko Katsumata
- Department of Biostatistics, University of Kentucky, Lexington, KY, USA
| | - Peter T Nelson
- Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA; Department of Pathology, University of Kentucky, Lexington, KY, USA
| | - Sally R Ellingson
- Division of Biomedical Informatics, University of Kentucky, Lexington, KY, USA
| | - David W Fardo
- Department of Biostatistics, University of Kentucky, Lexington, KY, USA; Sanders-Brown Center on Aging, University of Kentucky, Lexington, KY, USA.
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18
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Zaitseva II, Berggren PO, Zaitsev SV. Insulinotropic compounds decrease endothelial cell survival. Toxicol In Vitro 2016; 33:1-8. [PMID: 26883446 DOI: 10.1016/j.tiv.2016.02.004] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2015] [Revised: 01/05/2016] [Accepted: 02/10/2016] [Indexed: 10/22/2022]
Abstract
OBJECTIVES Hyperglycemia induces damage of vascular endothelial cells leading to diabetic complications. We investigated the effects of insulinotropic compounds and elevated glucose on endothelial cells in the absence or presence of vascular endothelial growth factor (VEGF). RESULTS Human umbilical vein endothelial cells (HUVECs) were treated with glibenclamide, repaglinide and insulinotropic imidazolines at high glucose concentration in the presence or absence of VEGF and viability, proliferation and nitric oxide production were measured. Hyperglycemia inhibited pro-survival effects of VEGF on endothelial cells. Glibenclamide and repaglinide decreased HUVEC viability at elevated glucose concentration in the absence but not in the presence of VEGF, without affecting HUVEC proliferation. Repaglinide also had some positive influence on HUVEC function elevating NO production in the presence of VEGF. Imidazolines showed different activities on endothelial cell survival. Efaroxan diminished HUVEC viability at elevated glucose concentration in the presence, however not in the absence of VEGF, while RX871024 decreased HUVEC survival regardless of the presence of VEGF. SIGNIFICANCE OF THE STUDY Our data demonstrate an important interplay between the actual insulinotropic compounds, VEGF and ambient glucose concentration affecting the survival of the vascular endothelial cells. Consequently, this interplay needs to be taken into consideration when designing novel oral antidiabetic compounds.
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Affiliation(s)
- Irina I Zaitseva
- Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-17176 Stockholm, Sweden
| | - Per-Olof Berggren
- Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-17176 Stockholm, Sweden
| | - Sergei V Zaitsev
- Rolf Luft Research Center for Diabetes and Endocrinology, Karolinska Institutet, SE-17176 Stockholm, Sweden; Lomonosov Moscow State University, Belozersky Institute of Physico-chemical Biology, Faculty of Bioengineering and Bioinformatics, Moscow 119992, Russia.
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19
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Sanchez RA, Sanabria H, Santos CDL, Ramirez AJ. Incretins and selective renal sodium-glucose co-transporter 2 inhibitors in hypertension and coronary heart disease. World J Diabetes 2015; 6:1186-1197. [PMID: 26380062 PMCID: PMC4564814 DOI: 10.4239/wjd.v6.i11.1186] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/25/2014] [Revised: 01/29/2015] [Accepted: 08/31/2015] [Indexed: 02/05/2023] Open
Abstract
Hyperglycemia is associated with an increased risk of cardiovascular disease, and the consequences of intensive therapy may depend on the mechanism of the anti-diabetic agent(s) used to achieve a tight control. In animal models, stable analogues of glucagon-like peptide-1 (GLP-1) were able to reduce body weight and blood pressure and also had favorable effects on ischemia following coronary reperfusion. In a similar way, dipeptidyl peptidase IV (DPP-IV) showed to have favorable effects in animal models of ischemia/reperfusion. This could be due to the fact that DPP-IV inhibitors were able to prevent the breakdown of GLP-1 and glucose-dependent insulinotropic polypeptide, but they also decreased the degradation of several vasoactive peptides. Preclinical data for GLP-1, its derivatives and inhibitors of the DPP-IV enzyme degradation suggests that these agents may be able to, besides controlling glycaemia, induce cardio-protective and vasodilator effects. Notwithstanding the many favorable cardiovascular effects of GLP-1/incretins reported in different studies, many questions remain unanswered due the limited number of studies in human beings that aim to examine the effects of GLP-1 on cardiovascular endpoints. For this reason, long-term trials searching for positive cardiovascular effects are now in process, such as the CAROLINA and CARMELINA trials, which are supported by small pilot studies performed in humans (and many more animal studies) with incretin-based therapies. On the other hand, selective renal sodium-glucose co-transporter 2 inhibitors were also evaluated in the prevention of cardiovascular outcomes in type 2 diabetes. However, it is quite early to draw conclusions, since data on cardiovascular outcomes and cardiovascular death are limited and long-term studies are still ongoing. In this review, we will analyze the mechanisms underlying the cardiovascular effects of incretins and, at the same time, we will present a critical position about the real value of these compounds in the cardiovascular system and its protection.
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20
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Cornell S, D'Souza J. Pharmacotherapy Considerations in Diabetes and Obesity: Setting Patients up for Success. Postgrad Med 2015; 126:100-9. [DOI: 10.3810/pgm.2014.03.2745] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
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21
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Synthesis and evaluation of multi-functional NO-donor/insulin-secretagogue derivatives for the treatment of type II diabetes and its cardiovascular complications. Bioorg Med Chem 2015; 23:422-8. [PMID: 25577707 DOI: 10.1016/j.bmc.2014.12.043] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2014] [Revised: 12/12/2014] [Accepted: 12/17/2014] [Indexed: 11/23/2022]
Abstract
Although there is a significant effort in the discovery of effective therapies to contrast both the pathological endocrine and metabolic aspects of diabetes and the endothelial dysfunction associated with this disease, no hypoglycemic drug has been proven to defeat the cardiovascular complications associated with type II diabetes. The aim of this research was to design new compounds exhibiting a double profile of hypoglycemic agents/NO-donors. The synthesis of molecules obtained by the conjunction of NO-donor moieties with two oral insulin-secretagogue drugs (repaglinide and nateglinide) was reported. NO-mediated vasorelaxing effects of the synthesized compounds were evaluated by functional tests on isolated endothelium-denuded rat aortic rings. The most potent molecule (4) was tested to evaluate the hypoglycemic and the anti-ischemic cardioprotective activities. This study indicates that 4 should represent a new insulin-secretagogue/NO-donor prodrug with an enhanced cardiovascular activity, which may contrast the pathological aspects of diabetes and endowed of cardioprotective activity.
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22
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Abstract
Table 3 provides an overview of the oral antihyperglycemic drugs reviewed in this article. A 2011 meta-analysis by Bennett and colleagues found low or insufficient quality of evidence favoring an initial choice of metformin, SUs, glinides, TZDs, or (table see text) DPP-4 inhibitors (alpha-glucosidase inhibitors, bromocriptine mesylate, and SGLT2 inhibitors were not included in this meta-analysis) with regard to the outcomes measures of all-cause mortality, cardiovascular events and mortality, and incidence of microvascular disease (retinopathy, nephropathy, and neuropathy) in previously healthy individuals with newly diagnosed T2DM. Likewise, the Bennett and colleagues meta-analysis judged these drugs to be of roughly equal efficacy with regard to reduction of HbA1c (1%–1.6%) from the pretreatment baseline. The ADOPT clinical trial of 3 different and, at the time, popular, oral monotherapies for T2DM provides support for the consensus recommendation of metformin as first-line therapy. The ADOPT trial showed slightly superior HbA1c reduction for rosiglitazone compared with metformin, which was in turn superior to glyburide. However, significant adverse events, including edema, weight gain, and fractures, were more common in the rosiglitazone-treated patients. The implication of this trial is that the combination of low cost, low risk, minimal adverse effects, and efficacy of metformin justifies use of this agent as the cornerstone of oral drug treatment of T2DM. Judicious use of metformin in groups formerly thought to be at high risk for lactic acidosis (ie, those with CHF, chronic kidney disease [eGFR >30 mL/min/1.73 m2], and the elderly) may be associated with mortality benefit rather than increased risk. Secondary and tertiary add-on drug therapy should be individualized based on cost, personal preferences, and overall treatment goals, taking into account the wishes and priorities of the patient.
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Affiliation(s)
- Stephen A Brietzke
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Missouri-Columbia, DC043 UMHC, 1 Hospital Drive, Columbia, MO 65212, USA.
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23
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Abstract
Sulfonylurea compounds were the first available oral antidiabetic agents and they remain an important tool in our quest for optimal glucose control. The sulfonylureas stimulate the release of insulin from pancreatic β-cells and have a number of extrapancreatic effects, including decreasing hepatic insulin clearance and reducing glucagon secretion in patients with type 2 diabetes. Although these agents have been the mainstay of pharmacotherapy for patients with type 2 diabetes mellitus (T2DM), their safety and clinical utility has been a matter of active debate in recent years, as their use is associated with risks of hypoglycemia and weight gain. We review the discovery and mechanisms of action of sulfonylureas, and the results of clinical trials to provide practical information on the pros and cons of their use in clinical practice. This review addresses advances in our understanding of mechanisms of action of sulfonylurea agents, their efficacy in T2DM, side effects, and impact on cardiovascular disease outcomes.
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Affiliation(s)
- Peter M Thulé
- Section Endocrinology and Metabolism, Atlanta VA Medical Center, Atlanta, GA, USA
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24
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Raymond T, Raymond R, Lincoff AM. Management of the patient with diabetes and coronary artery disease: a contemporary review. Future Cardiol 2014; 9:387-403. [PMID: 23668743 DOI: 10.2217/fca.13.22] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/08/2023] Open
Abstract
Diabetes mellitus is a metabolic disease with microvascular and macrovascular complications, and is well known to increase the risk of coronary atherosclerosis. Despite recent reductions in the prevalence of coronary artery disease and cardiovascular events in the USA, persons with diabetes remain up to four-times as likely to die of cardiovascular disease than the general population. Diabetes is associated with an atherogenic lipid profile, induces a hypercoagulable state, and increases coronary plaque volume, progression and instability. Medicinal and procedural treatments in the patient with diabetes should be multifactorial, targeting and managing the many coexisting risk factors that contribute to atherosclerosis. This type of treatment is complex and should be individualized, and guided by a careful review of recent literature. Here we discuss important clinical data and their impact on up-to-date recommendations for the management of coronary artery disease in the patient with Type 2 diabetes mellitus.
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Affiliation(s)
- Timothy Raymond
- Department of Cardiovascular Medicine, Cleveland Clinic, 9500 Euclid Avenue, Cleveland, OH 44195, USA
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25
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Glibenclamide decreases ATP-induced intracellular calcium transient elevation via inhibiting reactive oxygen species and mitochondrial activity in macrophages. PLoS One 2014; 9:e89083. [PMID: 24558474 PMCID: PMC3928368 DOI: 10.1371/journal.pone.0089083] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2013] [Accepted: 01/19/2014] [Indexed: 12/11/2022] Open
Abstract
Increasing evidence has revealed that glibenclamide has a wide range of anti-inflammatory effects. However, it is unclear whether glibenclamide can affect the resting and adenosine triphosphate (ATP)-induced intracellular calcium ([Ca2+]i) handling in Raw 264.7 macrophages. In the present study, [Ca2+]i transient, reactive oxygen species (ROS) and mitochondrial activity were measured by the high-speed TILLvisION digital imaging system using the indicators of Fura 2-am, DCFDA and rhodamine-123, respectively. We found that glibenclamide, pinacidil and other unselective K+ channel blockers had no effect on the resting [Ca2+]i of Raw 264.7 cells. Extracellular ATP (100 µM) induced [Ca2+]i transient elevation independent of extracellular Ca2+. The transient elevation was inhibited by an ROS scavenger (tiron) and mitochondria inhibitor (rotenone). Glibenclamide and 5-hydroxydecanoate (5-HD) also decreased ATP-induced [Ca2+]i transient elevation, but pinacidil and other unselective K+ channel blockers had no effect. Glibenclamide also decreased the peak of [Ca2+]i transient induced by extracellular thapsigargin (Tg, 1 µM). Furthermore, glibenclamide decreased intracellular ROS and mitochondrial activity. When pretreated with tiron and rotenone, glibenclamide could not decrease ATP, and Tg induced maximal [Ca2+]i transient further. We conclude that glibenclamide may inhibit ATP-induced [Ca2+]i transient elevation by blocking mitochondria KATP channels, resulting in decreased ROS generation and mitochondrial activity in Raw 264.7 macrophages.
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26
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Curione M, Di Bona S, Amato S, Turinese I, Tarquini G, Gatti A, Mandosi E, Rossetti M, Varrenti M, Salvatore S, Baiocco E, Morano S. Lack of the QTc physiologic decrease during cardiac stress test in patients with type 2 diabetes treated with secretagogues. Acta Diabetol 2014; 51:31-3. [PMID: 23114725 DOI: 10.1007/s00592-012-0438-6] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/07/2012] [Accepted: 10/11/2012] [Indexed: 10/27/2022]
Abstract
Patients with type 2 diabetes are at increased susceptibility to a prolonged QT interval. Furthermore, insulin secretagogues, drugs used to treat diabetes, may prolong QT interval and provoke arrhythmias. We evaluated whether secretagogues can affect QTc interval during cardiac stress test in 20 patients with type 2 diabetes treated with secretagogues. ECG stress test was performed in all patients. QTc interval was calculated both before cardiac stress test (BCST) and at acme of cardiac stress test (ACST). Diabetic patients treated with secretagogues showed longer QTc-ACST values than those treated with metformin only. QTc-ACST values resulted shorter than QTc-BCST values in control group. Diabetic patients treated with secretagogues showed QTc-ACST values significantly longer than QTc-BCST values. In our study, diabetic patients treated with secretagogues did not show the QTc physiologic decrease that is a protective against arrhythmias. These results suggest to evaluate, in these patients, QT length, even during routine cardiac stress test.
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27
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Martin GM, Chen PC, Devaraneni P, Shyng SL. Pharmacological rescue of trafficking-impaired ATP-sensitive potassium channels. Front Physiol 2013; 4:386. [PMID: 24399968 PMCID: PMC3870925 DOI: 10.3389/fphys.2013.00386] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2013] [Accepted: 12/09/2013] [Indexed: 12/25/2022] Open
Abstract
ATP-sensitive potassium (KATP) channels link cell metabolism to membrane excitability and are involved in a wide range of physiological processes including hormone secretion, control of vascular tone, and protection of cardiac and neuronal cells against ischemic injuries. In pancreatic β-cells, KATP channels play a key role in glucose-stimulated insulin secretion, and gain or loss of channel function results in neonatal diabetes or congenital hyperinsulinism, respectively. The β-cell KATP channel is formed by co-assembly of four Kir6.2 inwardly rectifying potassium channel subunits encoded by KCNJ11 and four sulfonylurea receptor 1 subunits encoded by ABCC8. Many mutations in ABCC8 or KCNJ11 cause loss of channel function, thus, congenital hyperinsulinism by hampering channel biogenesis and hence trafficking to the cell surface. The trafficking defects caused by a subset of these mutations can be corrected by sulfonylureas, KATP channel antagonists that have long been used to treat type 2 diabetes. More recently, carbamazepine, an anticonvulsant that is thought to target primarily voltage-gated sodium channels has been shown to correct KATP channel trafficking defects. This article reviews studies to date aimed at understanding the mechanisms by which mutations impair channel biogenesis and trafficking and the mechanisms by which pharmacological ligands overcome channel trafficking defects. Insight into channel structure-function relationships and therapeutic implications from these studies are discussed.
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Affiliation(s)
- Gregory M Martin
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University Portland, OR, USA
| | - Pei-Chun Chen
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University Portland, OR, USA
| | - Prasanna Devaraneni
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University Portland, OR, USA
| | - Show-Ling Shyng
- Department of Biochemistry and Molecular Biology, Oregon Health & Science University Portland, OR, USA
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28
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Nagendran J, Oudit GY, Bakal JA, Light PE, Dyck JRB, McAlister FA. Are users of sulphonylureas at the time of an acute coronary syndrome at risk of poorer outcomes? Diabetes Obes Metab 2013; 15:1022-8. [PMID: 23668425 DOI: 10.1111/dom.12126] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/19/2013] [Revised: 03/24/2013] [Accepted: 05/07/2013] [Indexed: 01/08/2023]
Abstract
AIMS Adenosine triphosphate sensitive potassium (K(ATP)) channel activity is cardioprotective during ischaemia. One of the purported mechanisms for sulphonylurea adverse effects is through inhibition of these channels. The purpose of this study is to examine whether patients using K(ATP) channel inhibitors at the time of an acute coronary syndrome are at greater risk of death or heart failure (HF) than those not exposed. METHODS Using linked administrative databases we identified all adults who had an acute coronary syndrome between April 2002 and October 2006 (n = 21 023). RESULTS Within 30 days of acute coronary syndrome, 5.3% of our cohort died and 15.6% were diagnosed with HF. Individuals with diabetes exhibited significantly higher risk of death (adjusted OR: 1.20, 95% CI: 1.03-1.40) and death or HF (aOR: 1.73, 95% CI: 1.59-1.89) than individuals without diabetes. However, there was no significantly increased risk of death (aOR: 1.00, 95% CI: 0.76-1.33) or death/HF (aOR: 1.06, 95% CI: 0.89-1.26) in patients exposed to K(ATP) channel inhibitors versus patients not exposed to K(ATP) channel inhibitors prior to their acute coronary syndrome. CONCLUSIONS Diabetes is associated with an increased risk of death or HF within 30 days of an acute coronary syndrome. However, we did not find any excess risk of death or HF associated with use of K(ATP) channel inhibitors at the time of an acute coronary syndrome, raising doubts about the hypothesis that sulphonylureas inhibit the cardioprotective effects of myocardial K(ATP) channels.
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Affiliation(s)
- J Nagendran
- Division of Cardiac Surgery, Department of Surgery, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada; Cardiovascular Research Centre, Faculty of Medicine and Dentistry, Mazankowski Alberta Heart Institute, University of Alberta, Edmonton, Alberta, Canada
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Guardado-Mendoza R, Prioletta A, Jiménez-Ceja LM, Sosale A, Folli F. The role of nateglinide and repaglinide, derivatives of meglitinide, in the treatment of type 2 diabetes mellitus. Arch Med Sci 2013; 9:936-43. [PMID: 24273582 PMCID: PMC3832818 DOI: 10.5114/aoms.2013.34991] [Citation(s) in RCA: 78] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 12/18/2012] [Accepted: 01/31/2013] [Indexed: 01/20/2023] Open
Abstract
Type 2 diabetes mellitus (T2DM) is one of the most common chronic diseases worldwide, presenting a great challenge to the public health systems due to high morbidity and mortality, because of frequent micro-/macro-vascular complications. Many treatment options are now available, with different efficacy as well as mechanisms of action to improve deranged glucose metabolism. We review some of the available data on derivatives of meglitinide, namely nateglinide and repaglinide. These two compounds increase insulin secretion by a mechanism similar to the one of sulfonylureas, but with a shorter half-life. Nateglinide and repaglinide, derivatives of meglitinides, have characteristic pharmacodynamic and pharmacokinetic properties that, together with their proposed mechanism of action, make them useful for type 2 diabetes mellitus, especially when used in combination therapy.
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Affiliation(s)
- Rodolfo Guardado-Mendoza
- Department of Medicine and Nutrition, Division of Health Sciences, University of Guanajuato, México
| | - Annamaria Prioletta
- Diabetes Center, ACISMOM Associazione Cavalieri Italiani Sovrano Militare Ordine Di Malta, Italy
| | - Lilia M. Jiménez-Ceja
- Department of Medicine and Nutrition, Division of Health Sciences, University of Guanajuato, México
| | | | - Franco Folli
- Department of Medicine, Diabetes Division, University of Texas Health Science Center at San Antonio, Texas, USA
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Dikalov SI, Nazarewicz RR. Angiotensin II-induced production of mitochondrial reactive oxygen species: potential mechanisms and relevance for cardiovascular disease. Antioxid Redox Signal 2013; 19:1085-94. [PMID: 22443458 PMCID: PMC3771548 DOI: 10.1089/ars.2012.4604] [Citation(s) in RCA: 233] [Impact Index Per Article: 21.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
SIGNIFICANCE The role of reactive oxygen species (ROS) in angiotensin II (AngII) induced endothelial dysfunction, cardiovascular and renal remodeling, inflammation, and fibrosis has been well documented. The molecular mechanisms of AngII pathophysiological activity involve the stimulation of NADPH oxidases, which produce superoxide and hydrogen peroxide. AngII also increases the production of mitochondrial ROS, while the inhibition of AngII improves mitochondrial function; however, the specific molecular mechanisms of the stimulation of mitochondrial ROS is not clear. RECENT ADVANCES Interestingly, the overexpression of mitochondrial thioredoxin 2 or mitochondrial superoxide dismutase attenuates AngII-induced hypertension, which demonstrates the importance of mitochondrial ROS in AngII-mediated cardiovascular diseases. CRITICAL ISSUES Although mitochondrial ROS plays an important role in normal physiological cell signaling, AngII, high glucose, high fat, or hypoxia may cause the overproduction of mitochondrial ROS, leading to the feed-forward redox stimulation of NADPH oxidases. This vicious cycle may contribute to the development of pathological conditions and facilitate organ damage in hypertension, atherosclerosis, and diabetes. FUTURE DIRECTIONS The development of antioxidant strategies specifically targeting mitochondria could be therapeutically beneficial in these disease conditions.
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Affiliation(s)
- Sergey I Dikalov
- Free Radicals in Medicine Core, Division of Clinical Pharmacology, Vanderbilt University Medical Center , Nashville, Tennessee
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Glibenclamide induces collagen IV catabolism in high glucose-stimulated mesangial cells. EXPERIMENTAL DIABETES RESEARCH 2012; 2012:183535. [PMID: 23008698 PMCID: PMC3447387 DOI: 10.1155/2012/183535] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/05/2012] [Revised: 08/07/2012] [Accepted: 08/08/2012] [Indexed: 12/12/2022]
Abstract
We have shown the full prevention of mesangial expansion in insulin-deficient diabetic rats by treatment with clinically-relevant dosages of glibenclamide (Glib). Studies in mesangial cells (MCs) also demonstrated reduction in the high glucose (HG)-induced accumulation of collagens, proposing that this was due to increased catabolism. In the present study, we investigated the signaling pathways that may be implicated in Glib action. Rat primary MCs were exposed to HG for 8 weeks with or without Glib in therapeutic (0.01 μM) or supratherapeutic (1.0 μM) concentrations. We found that HG increased collagen IV protein accumulation and PAI-1 mRNA and protein expression, in association with decreased cAMP generating capacity and decreased PKA activity. Low Glib increased collagen IV mRNA but fully prevented collagen IV protein accumulation and PAI-1 overexpression while enhancing cAMP formation and PKA activity. MMP2 mRNA, protein expression and gelatinolytic activity were also enhanced. High Glib was, overall, ineffective. In conclusion, low dosage/concentration Glib prevents HG-induced collagen accumulation in MC by enhancing collagen catabolism in a cAMP-PKA-mediated PAI-1 inhibition.
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Kitasato L, Tojo T, Hatakeyama Y, Kameda R, Hashikata T, Yamaoka-Tojo M. Postprandial hyperglycemia and endothelial function in type 2 diabetes: focus on mitiglinide. Cardiovasc Diabetol 2012; 11:79. [PMID: 22748110 PMCID: PMC3492036 DOI: 10.1186/1475-2840-11-79] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/14/2012] [Accepted: 06/18/2012] [Indexed: 12/19/2022] Open
Abstract
The risk of cardiovascular complication in a diabetes patient is similar to that in a nondiabetic patient with a history of myocardial infarction. Although intensive control of glycemia achieved by conventional antidiabetic agents decreases microvascular complications such as retinopathy and nephropathy, no marked effect has been reported on macrovascular complications or all-cause mortality. Evidence from VADT, ACCORD, and ADVANCE would suggest that glycemic control has little effect on macrovascular outcomes. Moreover, in the case of ACCORD, intensive glycemic control may be associated with an increased risk of mortality. There is sufficient evidence that suggests that postprandial hyperglycemia may be an independent risk factor for cardiovascular disease in diabetes patients. However, there are no prospective clinical trials supporting the recommendation that lowering postprandial blood glucose leads to lower risk of cardiovascular outcomes. Mitiglinide is a short-acting insulinotropic agent used in type 2 diabetes treatment. It has a rapid stimulatory effect on insulin secretion and reduces postprandial plasma glucose level in patients with type 2 diabetes. Because of its short action time, it is unlikely to exert adverse effects related to hypoglycemia early in the morning and between meals. Mitiglinide reduces excess oxidative stress and inflammation, plays a cardioprotective role, and improves postprandial metabolic disorders. Moreover, mitiglinide add-on therapy with pioglitazone favorably affects the vascular endothelial function in type 2 diabetes patients. These data suggest that mitiglinide plays a potentially beneficial role in the improvement of postprandial hyperglycemia in type 2 diabetes patients and can be used to prevent cardiovascular diseases. Although the results of long-term, randomized, placebo-controlled trials for determining the cardiovascular effects of mitiglinide on clinical outcomes are awaited, this review is aimed at summarizing substantial insights into this topic.
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Affiliation(s)
- Lisa Kitasato
- Kitasato University Graduate School of Medical Sciences, Sagamihara, Japan
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Clark R, Männikkö R, Stuckey DJ, Iberl M, Clarke K, Ashcroft FM. Mice expressing a human K(ATP) channel mutation have altered channel ATP sensitivity but no cardiac abnormalities. Diabetologia 2012; 55:1195-204. [PMID: 22252471 PMCID: PMC3296019 DOI: 10.1007/s00125-011-2428-6] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/06/2011] [Accepted: 11/28/2011] [Indexed: 11/29/2022]
Abstract
AIMS/HYPOTHESIS Patients with severe gain-of-function mutations in the Kir6.2 subunit of the ATP-sensitive potassium (K(ATP)) channel, have neonatal diabetes, muscle hypotonia and mental and motor developmental delay-a condition known as iDEND syndrome. However, despite the fact that Kir6.2 forms the pore of the cardiac K(ATP) channel, patients show no obvious cardiac symptoms. The aim of this project was to use a mouse model of iDEND syndrome to determine whether iDEND mutations affect cardiac function and cardiac K(ATP) channel ATP sensitivity. METHODS We performed patch-clamp and in vivo cine-MRI studies on mice in which the most common iDEND mutation (Kir6.2-V59M) was targeted to cardiac muscle using Cre-lox technology (m-V59M mice). RESULTS Patch-clamp studies of isolated cardiac myocytes revealed a markedly reduced K(ATP) channel sensitivity to MgATP inhibition in m-V59M mice (IC(50) 62 μmol/l compared with 13 μmol/l for littermate controls). In vivo cine-MRI revealed there were no gross morphological differences and no differences in heart rate, end diastolic volume, end systolic volume, stroke volume, ejection fraction, cardiac output or wall thickening between m-V59M and control hearts, either under resting conditions or under dobutamine stress. CONCLUSIONS/INTERPRETATION The common iDEND mutation Kir6.2-V59M decreases ATP block of cardiac K(ATP) channels but was without obvious effect on heart function, suggesting that metabolic changes fail to open the mutated channel to an extent that affects function (at least in the absence of ischaemia). This may have implications for the choice of sulfonylurea used to treat neonatal diabetes.
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Affiliation(s)
- R. Clark
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford, OX1 3PT UK
- OXION, University of Oxford, Oxford, UK
| | - R. Männikkö
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford, OX1 3PT UK
- OXION, University of Oxford, Oxford, UK
- Present Address: Molecular Neuroscience, Institute of Neurology, UCL, London, UK
| | - D. J. Stuckey
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford, OX1 3PT UK
- Present Address: Biological Imaging Centre, National Heart and Lung Institute, Imperial College, Hammersmith Hospital, London, UK
| | - M. Iberl
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford, OX1 3PT UK
- OXION, University of Oxford, Oxford, UK
| | - K. Clarke
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford, OX1 3PT UK
- OXION, University of Oxford, Oxford, UK
| | - F. M. Ashcroft
- Henry Wellcome Centre for Gene Function, Department of Physiology, Anatomy and Genetics, Parks Road, Oxford, OX1 3PT UK
- OXION, University of Oxford, Oxford, UK
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Differential effects of sulfonylurea derivatives on vascular ATP-sensitive potassium channels. Eur J Pharmacol 2012; 681:75-9. [DOI: 10.1016/j.ejphar.2012.02.006] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2012] [Accepted: 02/09/2012] [Indexed: 12/25/2022]
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Dikalov S. Cross talk between mitochondria and NADPH oxidases. Free Radic Biol Med 2011; 51:1289-301. [PMID: 21777669 PMCID: PMC3163726 DOI: 10.1016/j.freeradbiomed.2011.06.033] [Citation(s) in RCA: 600] [Impact Index Per Article: 46.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/04/2011] [Revised: 06/27/2011] [Accepted: 06/29/2011] [Indexed: 02/07/2023]
Abstract
Reactive oxygen species (ROS) play an important role in physiological and pathological processes. In recent years, a feed-forward regulation of the ROS sources has been reported. The interactions between the main cellular sources of ROS, such as mitochondria and NADPH oxidases, however, remain obscure. This work summarizes the latest findings on the role of cross talk between mitochondria and NADPH oxidases in pathophysiological processes. Mitochondria have the highest levels of antioxidants in the cell and play an important role in the maintenance of cellular redox status, thereby acting as an ROS and redox sink and limiting NADPH oxidase activity. Mitochondria, however, are not only a target for ROS produced by NADPH oxidase but also a significant source of ROS, which under certain conditions may stimulate NADPH oxidases. This cross talk between mitochondria and NADPH oxidases, therefore, may represent a feed-forward vicious cycle of ROS production, which can be pharmacologically targeted under conditions of oxidative stress. It has been demonstrated that mitochondria-targeted antioxidants break this vicious cycle, inhibiting ROS production by mitochondria and reducing NADPH oxidase activity. This may provide a novel strategy for treatment of many pathological conditions including aging, atherosclerosis, diabetes, hypertension, and degenerative neurological disorders in which mitochondrial oxidative stress seems to play a role. It is conceivable that the use of mitochondria-targeted treatments would be effective in these conditions.
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Affiliation(s)
- Sergey Dikalov
- Division of Cardiology, Emory University School of Medicine, Atlanta, GA 30322, USA.
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Otani H. Oxidative stress as pathogenesis of cardiovascular risk associated with metabolic syndrome. Antioxid Redox Signal 2011; 15:1911-26. [PMID: 21126197 DOI: 10.1089/ars.2010.3739] [Citation(s) in RCA: 119] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Metabolic syndrome (MetS) is characterized by accumulation of visceral fat associated with the clustering of metabolic and pathophysiological cardiovascular risk factors: impaired glucose tolerance, dyslipidemia, and hypertension. Although the definition of MetS is different among countries, visceral obesity is an indispensable component of MetS. A growing body of evidence suggests that increased oxidative stress to adipocytes is central to the pathogenesis of cardiovascular disease in MetS. Increased oxidative stress to adipocytes causes dysregulated expression of inflammation-related adipocytokines in MetS, which contributes to obesity-associated vasculopathy and cardiovascular risk primarily through endothelial dysfunction. The purpose of present review is to unravel the mechanistic link between oxidative stress and cardiovascular risk in MetS, focusing on insulin resistance, hypertension, and atherosclerosis. Then, therapeutic opportunities translated from the bench to bedside will be provided to develop novel strategies to cardiovascular risk factors in MetS.
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Affiliation(s)
- Hajime Otani
- Second Department of Internal Medicine, Kansai Medical University, 10-15-Fumizono-cho, Moriguchi City, Japan.
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Erdmann E, Charbonnel B, Wilcox R. Thiazolidinediones and cardiovascular risk - a question of balance. Curr Cardiol Rev 2011; 5:155-65. [PMID: 20676274 PMCID: PMC2822138 DOI: 10.2174/157340309788970333] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/16/2008] [Revised: 09/04/2008] [Accepted: 09/04/2008] [Indexed: 12/13/2022] Open
Abstract
BACKGROUND Several recent meta-analyses of adverse event data from randomized controlled trials with rosiglitazone reveal a possible association between this thiazolidinedione and an increased risk of ischemic myocardial events. This has led to debate on the overall clinical benefit of glitazone therapy for type 2 diabetes. Pioglitazone, on the other hand, has the most extensive cardiovascular outcomes database of all current glucose-lowering therapies, including a large prospective randomized controlled trial designed specifically to assess cardiovascular outcomes (PROactive). The available data suggest that pioglitazone is associated with a reduction in macrovascular risk. AIMS In this review, we highlight some of the key factors that need to be considered when assessing the net clinical benefit of thiazolidinediones, focussing on both class effects and those specific to either rosiglitazone or pioglitazone. RESULTS For pioglitazone there appears to be no increase in the risk of overall macrovascular events and no adverse clinical consequences of developing signs of heart failure. Furthermore, there is good evidence of significant benefit regarding the composite of death, MI or stroke. CONCLUSION The benefits seen with pioglitazone appear to outweigh the risks.
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Affiliation(s)
- Erland Erdmann
- Clinic III for Internal Medicine and Cardiology, University of Cologne, Cologne, Germany
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Abstract
There is a rising worldwide prevalence of diabetes, especially type 2 diabetes mellitus (T2DM), which is one of the most challenging health problems in the 21st century. The associated complications of diabetes, such as cardiovascular disease, peripheral vascular disease, stroke, diabetic neuropathy, amputations, renal failure, and blindness result in increasing disability, reduced life expectancy, and enormous health costs. T2DM is a polygenic disease characterized by multiple defects in insulin action in tissues and defects in pancreatic insulin secretion, which eventually leads to loss of pancreatic insulin-secreting cells. The treatment goals for T2DM patients are effective control of blood glucose, blood pressure, and lipids (if elevated) and, ultimately, to avert the serious complications associated with sustained tissue exposure to excessively high glucose concentrations. Prevention and control of diabetes with diet, weight control, and physical activity has been difficult. Treatment of T2DM has centered on increasing insulin levels, either by direct insulin administration or oral agents that promote insulin secretion, improving sensitivity to insulin in tissues, or reducing the rate of carbohydrate absorption from the gastrointestinal tract. This review presents comprehensive and up-to-date information on the mechanism(s) of action, efficacy, pharmacokinetics, pleiotropic effects, drug interactions, and adverse effects of the newer antidiabetic drugs, including (1) peroxisome proliferator-activated-receptor-γ agonists (thiazolidinediones, pioglitazone, and rosiglitazone); (2) the incretin, glucagon-like peptide-) receptor agonists (incretin-mimetics, exenatide. and liraglutide), (3) inhibitors of dipeptidyl-peptidase-4 (incretin enhancers, sitagliptin, and vildagliptin), (4) short-acting, nonsulfonylurea secretagogue, meglitinides (repaglinide and nateglinide), (5) amylin anlog-pramlintide, (6) α-glucosidase inhibitors (miglitol and voglibose), and (7) colesevelam (a bile acid sequestrant). In addition, information is presented on drug candidates in clinical trials, experimental compounds, and some plants used in the traditional treatment of diabetes based on experimental evidence. In the opinion of this reviewer, therapy based on orally active incretins and incretin mimetics with long duration of action that will be efficacious, preserve the β-cell number/function, and block the progression of diabetes will be highly desirable. However, major changes in lifestyle factors such as diet and, especially, exercise will also be needed if the growing burden of diabetes is to be contained.
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Gore MO, McGuire DK. Resolving drug effects from class effects among drugs for type 2 diabetes mellitus: more support for cardiovascular outcome assessments. Eur Heart J 2011; 32:1832-4. [PMID: 21471136 DOI: 10.1093/eurheartj/ehr019] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/26/2023] Open
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Richard JW, Raskin P. Updated review: improved glycemic control with repaglinide-metformin in fixed combination for patients with type 2 diabetes. CLINICAL MEDICINE INSIGHTS-ENDOCRINOLOGY AND DIABETES 2011; 4:29-37. [PMID: 22879792 PMCID: PMC3411545 DOI: 10.4137/cmed.s5094] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
As the prevalence of type 2 diabetes continues to rise, new drug therapies will need to be explored to prevent morbidity and mortality associated with diabetes as well as growing health care costs. Type 2 diabetes is characterized by decreased insulin secretion and sensitivity. Numerous oral medications are currently approved for the treatment of type 2 diabetes. A treat-to-failure approach has traditionally been adopted with step-wise additions of oral medications; however, a growing frequency of treatment failures with monotherapy has led to the use of combination therapies earlier in the treatment of type 2 diabetes. One such combination regimen is repaglinide (a prandial glucose optimizer that increases insulin release) plus metformin (an insulin sensitizer that inhibits hepatic glucose output and increases peripheral glucose uptake while minimizing weight gain). Findings from several clinical trials have shown repaglinide plus metformin combination therapy to be superior to either monotherapy with significant reductions in hemoglobin A1C and fasting glucose values. Repaglinide used in combination also has shown less incidence of hypoglycemia compared with other combination therapies such as sulphonylureas plus metformin. Repaglinide plus metformin combination therapy appears to be a valuable therapeutic option for type 2 diabetic patients seeking a less complex drug regimen while potentially achieving better glucose control if currently inadequately controlled on monotherapy.
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Affiliation(s)
- John W Richard
- Department of Internal Medicine, Division of Endocrinology, Nutrition, Metabolism, and Diabetes, Southwestern Medical Center, Dallas, TX, USA
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Fischer A, Schmidt C, Lachenicht S, Grittner D, Winkler M, Wrobel T, Rood A, Lemoine H, Frank W, Braun M. Synthesis of Benzofuran, Benzothiophene, and Benzothiazole-Based Thioamides and their Evaluation as KATP Channel Openers. ChemMedChem 2010; 5:1749-59. [DOI: 10.1002/cmdc.201000297] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Clark RH, McTaggart JS, Webster R, Mannikko R, Iberl M, Sim XL, Rorsman P, Glitsch M, Beeson D, Ashcroft FM. Muscle dysfunction caused by a KATP channel mutation in neonatal diabetes is neuronal in origin. Science 2010; 329:458-61. [PMID: 20595581 DOI: 10.1126/science.1186146] [Citation(s) in RCA: 80] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Gain-of-function mutations in Kir6.2 (KCNJ11), the pore-forming subunit of the adenosine triphosphate (ATP)-sensitive potassium (KATP) channel, cause neonatal diabetes. Many patients also suffer from hypotonia (weak and flaccid muscles) and balance problems. The diabetes arises from suppressed insulin secretion by overactive KATP channels in pancreatic beta-cells, but the source of the motor phenotype is unknown. By using mice carrying a human Kir6.2 mutation (Val59-->Met59) targeted to either muscle or nerve, we show that analogous motor impairments originate in the central nervous system rather than in muscle or peripheral nerves. We also identify locomotor hyperactivity as a feature of KATP channel overactivity. These findings suggest that drugs targeted against neuronal, rather than muscle, KATP channels are needed to treat the motor deficits and that such drugs require high blood-brain barrier permeability.
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Affiliation(s)
- Rebecca H Clark
- Department of Physiology, Anatomy and Genetics, University of Oxford, Parks Road, Oxford, OX1 3PT, UK
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Amann T, Schell S, Kühner P, Winkler M, Schwanstecher M, Russ U, Quast U. Substitution of the Walker A lysine by arginine in the nucleotide-binding domains of sulphonylurea receptor SUR2B: effects on ligand binding and channel activity. Naunyn Schmiedebergs Arch Pharmacol 2010; 381:507-16. [PMID: 20352196 DOI: 10.1007/s00210-010-0510-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2009] [Accepted: 02/28/2010] [Indexed: 10/19/2022]
Abstract
Sulphonylurea receptors (SURs) serve as regulatory subunits of ATP-sensitive K(+) channels. SURs are members of the ATP-binding cassette (ABC) protein superfamily and contain two conserved nucleotide-binding domains (NBDs) which bind and hydrolyse MgATP; in addition, they carry the binding sites for the sulphonylureas like glibenclamide (GBC) which close the channel and for the K(ATP) channel openers such as P1075. Here we have exchanged the conserved Lys in the Walker A motif by Arg in both NBDs of SUR2B, the regulatory subunit of the vascular K(ATP) channel. Then the effect of the mutation on the ATPase-dependent binding of GBC and P1075 to SUR2B and on the activity of the recombinant vascular (Kir6.1/SUR2B) channel was assessed. Surprisingly, in the absence of MgATP, the mutation weakened binding of P1075 and the extent of allosteric inhibition of GBC binding by P1075. The mutation abolished most, but not all, of the MgATP effects on the binding of GBC and P1075 and prevented nucleotide-induced activation of the channel which relies on SUR reaching the posthydrolytic (MgADP-bound) state; the mutant channel was, however, opened by P1075 at higher concentrations. The data provide evidence that mutant SUR2B binds MgATP but that the posthydrolytic state is insufficiently populated. This suggests that the mutation locks SUR2B in an MgATP-binding prehydrolytic-like state; binding of P1075 may induce a posthydrolytic-like conformation to open the channel.
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Affiliation(s)
- Tobias Amann
- Department of Pharmacology and Experimental Therapy, Institute of Experimental and Clinical Pharmacology and Toxicology, Eberhard-Karls-University Hospitals and Clinics, University of Tübingen, Wilhelmstr. 56, 72074, Tübingen, Germany
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Glinide, but not sulfonylurea, can evoke insulin exocytosis by repetitive stimulation: imaging analysis of insulin exocytosis by secretagogue-induced repetitive stimulations. EXPERIMENTAL DIABETES RESEARCH 2009; 2009:278762. [PMID: 20069052 PMCID: PMC2801449 DOI: 10.1155/2009/278762] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/13/2009] [Revised: 09/14/2009] [Accepted: 11/15/2009] [Indexed: 12/31/2022]
Abstract
To investigate the different effects between sulfonylurea (SU) and glinide drugs in insulin secretion, pancreatic β-cells were repeatedly stimulated with SU (glimepiride) or glinide (mitiglinide). Total internal reflection fluorescent (TIRF) microscopy revealed that secondary stimulation with glimepiride, but not glucose and mitiglinide, failed to evoke fusions of insulin granules although primary stimulation with glucose, glimepiride, and mitiglinide induced equivalent numbers of exocytotic responses. Glimepiride, but not glucose and mitiglinide, induced abnormally sustained [Ca2+]i elevations and reductions of docked insulin granules on the plasma membrane. Our data suggest that the effect of glinide on insulin secretory mechanisms is similar to that of glucose.
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Lachenicht S, Fischer A, Schmidt C, Winkler M, Rood A, Lemoine H, Braun M. Synthesis of Modified 4H-1,2,4-Benzothiadiazine-1,1-dioxides and Determination of their Affinity and Selectivity for Different Types of KATPChannels. ChemMedChem 2009; 4:1850-8. [DOI: 10.1002/cmdc.200900261] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
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Voulgari C, Tentolouris N. Combination of nateglinide with thiazolidinediones in Type 2 diabetes. Expert Rev Endocrinol Metab 2009; 4:537-552. [PMID: 30780794 DOI: 10.1586/eem.09.40] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Insulin sensitivity and insulin secretion are reciprocally related such that insulin resistance is adapted by increased insulin secretion to maintain normal glucose and lipid homeostasis. Treatment of Type 2 diabetes should aim to restore and sustain the normal relationship between insulin sensitivity and secretion. Nateglinide is a rapid-onset, short-acting insulin-secretion enhancer that restores early-phase insulin secretion, reduces postprandial glucose excursions and prevents long-term hyperinsulinemia. Given its mechanism of action, it is evident that nateglinide would be more effective when used in combination with an insulin sensitizer, such as the thiazolidinediones. Thiazolidinediones do not stimulate insulin release and, therefore, are potentially suitable candidates for combination therapy with an insulin-secretion enhancer, such as nateglinide. Combination therapy of thiazolidinediones with nateglinide is effective, carries low risk of hypoglycemia and is suitable for patients with moderate renal impairment, although weight gain and edema are common side effects. Further studies are needed to determine whether nateglinide in combination with thiazolidinediones will help clinicians better achieve their treatment goals in targeting Type 2 diabetes. Moreover, comparative studies between nateglinide and medications targeting postprandial glycemia, such as dipeptidyl peptidase-4 inhibitors and glucagon-like peptide-1 analogues, are necessary. This article summarizes data concerning the mechanism of action, efficacy and safety of therapy with nateglinide and thiazolidinediones as monotherapy and in combination treatment, and aims at a better understanding of the substrate defects their synergy hopes to defy.
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Affiliation(s)
- Christina Voulgari
- a First Department of Propaedeutic Medicine, Athens University Medical School, Laiko General Hospital, 17 Agiou Thoma Street, 11527, Athens, Greece.
| | - Nicholas Tentolouris
- b First Department of Propaedeutic Medicine, Athens University Medical School, Laiko General Hospital, 17 Agiou Thoma Street, 11527, Athens, Greece.
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Cardiovascular consequences of drugs used for the treatment of diabetes: potential promise of incretin—based therapies. ACTA ACUST UNITED AC 2009; 3:245-59. [DOI: 10.1016/j.jash.2009.04.001] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2008] [Revised: 03/23/2009] [Accepted: 04/06/2009] [Indexed: 11/20/2022]
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Golomb E, Nyska A, Schwalb H. Occult Cardiotoxicity—Toxic Effects on Cardiac Ischemic Tolerance. Toxicol Pathol 2009; 37:572-93. [DOI: 10.1177/0192623309339503] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
The outcome of cardiac ischemic events depends not only on the extent and duration of the ischemic stimulus but also on the myocardial intrinsic tolerance to ischemic injury. Cardiac ischemic tolerance reflects myocardial functional reserves that are not always used when the tissue is appropriately oxygenated. Ischemic tolerance is modulated by ubiquitous signal transduction pathways, transcription factors and cellular enzymes, converging on the mitochondria as the main end effector. Therefore, drugs and toxins affecting these pathways may impair cardiac ischemic tolerance without affecting myocardial integrity or function in oxygenated conditions. Such effect would not be detected by current toxicological studies but would considerably influence the outcome of ischemic events. The authors refer to such effect as “occult cardiotoxicity.” In this review, the authors summarize current knowledge about main mechanisms that determine cardiac ischemic tolerance, methods to assess it, and the effects of drugs and toxins on it. The authors offer a view that low cardiac ischemic tolerance is a premorbid status and, therefore, that occult cardiotoxicity is a significant potential source of cardiac morbidity. The authors propose that toxicologic assessment of compounds would include the assessment of their effect on cardiac ischemic tolerance.
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Affiliation(s)
- Eliahu Golomb
- Department of Pathology, Shaare Zedek Medical Center, Jerusalem 91031, Israel
| | - Abraham Nyska
- Department of Pathology, Sackler School of Medicine, Tel Aviv University, Tel-Aviv 69978, Israel
| | - Herzl Schwalb
- The Joseph Lunenfeld Cardiac Surgery Research Center, Department of Cardiothoracic Surgery, Hadassah-Hebrew University Medical Center, Jerusalem 91120, Israel
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Abstract
Our objective was to determine whether human diabetic myocardium is amenable to the cardioprotective actions of ischaemic preconditioning. Human right atrial appendages were harvested from diabetic and non-diabetic patients undergoing elective coronary artery bypass graft surgery. The atrial trabeculae were isolated and subjected to 90 min. of hypoxia followed by 120 min. of reoxygenation, following which the percentage recovery of baseline contractile function was determined. The atrial trabeculae were randomized to: (i) controls (groups 1 and 3); (ii) standard hypoxic preconditioning (HPC) protocol consisting of 4 min. of hypoxia/16 min. of reoxygenation before the 90 min. index hypoxic period (groups 2 and 4); (iii) Prolonged HPC protocol consisting of: 7 min. of hypoxia /16 min. of reoxygenation before the index hypoxic period (group 5). In addition, basal levels of Akt phosphorylation were determined in right atrial appendages harvested from non-diabetic patients and diabetic patients to determine whether PI3K-Akt signalling is down-regulated in the diabetic heart. Standard HPC improved baseline contractile function in human atrial trabeculae harvested from non-diabetic patients (52.4 +/- 3.8% with HPC versus 30.0 +/- 3.2% in control: P = 0.001; N = 6/group), but not in atrial trabeculae isolated from diabetic patients (22.6 +/- 3.3% with HPC versus 28.5 +/- 1.9% in control: P > 0.05; N = 6/group). However, the prolonged HPC protocol did improve baseline contractile function in atrial trabeculae harvested from diabetic patients (42.0 +/- 2.4% with HPC versus 28.5 +/- 1.9% in control: P= 0.001; N > or = 6/group). Western blot analysis demonstrated lower levels of phosphorylated Akt in diabetic myocardium compared to non-diabetic myocardium (0.13 +/- 0.03 arbitrary units versus 0.39 +/- 0.11 arbitrary units: P= 0.047; N > or = 4/group). From the data obtained it appears that the threshold for preconditioning the diabetic myocardium is elevated which may be related to the down-regulation of the PI3K-Akt pathway.
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Affiliation(s)
- Vivek Sivaraman
- The Hatter Cardiovascular Institute, University College London, UK
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Theoretical study of molecular structure, pKa, lipophilicity, solubility, absorption, and polar surface area of some hypoglycemic agents. ACTA ACUST UNITED AC 2009. [DOI: 10.1016/j.theochem.2008.11.021] [Citation(s) in RCA: 59] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
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