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Haas B, Hass MDS, Voltz A, Vogel M, Walther J, Biswas A, Hass D, Pfeifer A. Sulfonylureas exert antidiabetic action on adipocytes by inhibition of PPARγ serine 273 phosphorylation. Mol Metab 2024; 85:101956. [PMID: 38735390 PMCID: PMC11112612 DOI: 10.1016/j.molmet.2024.101956] [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] [Received: 12/18/2023] [Revised: 03/04/2024] [Accepted: 05/07/2024] [Indexed: 05/14/2024] Open
Abstract
OBJECTIVE Sulfonylureas (SUs) are still among the mostly prescribed antidiabetic drugs with an established mode of action: release of insulin from pancreatic β-cells. In addition, effects of SUs on adipocytes by activation of the nuclear receptor peroxisome proliferator-activated receptor γ (PPARγ) have been described, which might explain their insulin-sensitizing potential observed in patients. However, there is a discrepancy between the impact of SUs on antidiabetic action and their rather moderate in vitro effect on PPARγ transcriptional activity. Recent studies have shown that some PPARγ ligands can improve insulin sensitivity by blocking PPARγ Ser-273 phosphorylation without having full agonist activity. It is unknown if SUs elicit their antidiabetic effects on adipocytes by inhibition of PPARγ phosphorylation. Here, we investigated if binding of SUs to PPARγ can interfere with PPARγ Ser-273 phosphorylation and determined their antidiabetic actions in vitro in primary human white adipocytes and in vivo in high-fat diet (HFD) obese mice. METHODS Primary human white preadipocytes were differentiated in the presence of glibenclamide, glimepiride and PPARγ ligands rosiglitazone and SR1664 to compare PPARγ Ser-273 phosphorylation, glucose uptake and adipokine expression. Transcriptional activity at PPARγ was determined by luciferase assays, quantification of PPARγ Ser-273 phosphorylation was determined by Western blotting and CDK5 kinase assays. In silico modelling was performed to gain insight into the binding characteristics of SUs to PPARγ. HFD mice were administered SUs and rosiglitazone for 6 days. PPARγ Ser-273 phosphorylation in white adipose tissue (WAT), body composition, glucose tolerance, adipocyte morphology and expression levels of genes involved in PPARγ activity in WAT and brown adipose tissue (BAT) were evaluated. RESULTS SUs inhibit phosphorylation of PPARγ at Ser-273 in primary human white adipocytes and exhibit a positive antidiabetic expression profile, which is characterized by up regulation of insulin-sensitizing and down regulation of insulin resistance-inducing adipokines. We demonstrate that SUs directly bind to PPARγ by in silico modelling and inhibit phosphorylation in kinase assays to a similar extend as rosiglitazone and SR1664. In HFD mice SUs reduce PPARγ phosphorylation in WAT and have comparable effects on gene expression to rosiglitazone. In BAT SUs increase UCP1 expression and reduce lipid droplets sizes. CONCLUSIONS Our findings indicate that a part of SUs extra-pancreatic effects on adipocytes in vitro and in vivo is probably mediated via their interference with PPARγ phosphorylation rather than via classical agonistic activity at clinical concentrations.
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Affiliation(s)
- Bodo Haas
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, Bonn, Germany.
| | - Moritz David Sebastian Hass
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, Bonn, Germany; MVZ für Hämostaseologie, Rheumathologie, Endokrinologie, Allgemeinmedizin und Transfusionsmedizin, München, Germany
| | - Alexander Voltz
- Institute of Pharmacology and Toxicology, University Hospital, University of Bonn, Bonn, Germany
| | - Matthias Vogel
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, Bonn, Germany
| | - Julia Walther
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, Bonn, Germany
| | - Arijit Biswas
- Institute of Experimental Hematology and Transfusion Medicine, University Hospital, University of Bonn, Bonn, Germany
| | - Daniela Hass
- Institute of Pharmacology and Toxicology, University Hospital, University of Bonn, Bonn, Germany; Institute for Diabetes and Cancer, Helmholtz Munich, German Center for Diabetes Research, Neuherberg, Germany
| | - Alexander Pfeifer
- Institute of Pharmacology and Toxicology, University Hospital, University of Bonn, Bonn, Germany
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Petrović A, Madić V, Stojanović G, Zlatanović I, Zlatković B, Vasiljević P, Đorđević L. Antidiabetic effects of polyherbal mixture made of Centaurium erythraea, Cichorium intybus and Potentilla erecta. JOURNAL OF ETHNOPHARMACOLOGY 2024; 319:117032. [PMID: 37582477 DOI: 10.1016/j.jep.2023.117032] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/01/2023] [Revised: 07/29/2023] [Accepted: 08/11/2023] [Indexed: 08/17/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE The polyherbal mixture made of Centaurium erythraea aerial parts and Cichorium intybus roots and Potentilla erecta rhizomes has been used for centuries to treat both the primary and secondary complications of diabetes. AIM OF THE STUDY As a continuation of our search for the most effective herbal mixture used as an ethnopharmacological remedy for diabetes, this study aimed to compare the in vitro biological activities of this polyherbal mixture and its individual ingredients, and, most importantly, to validate the ethnopharmacological value of the herbal mixture through evaluation of its phytochemical composition, its potential in vivo toxicity and its effect on diabetes complications. MATERIALS AND METHODS Phytochemical analysis was performed using HPLC-UV. Antioxidant activity was estimated via the DPPH test. Potential cytotoxicity/anticytotoxicity was assessed using an in vitro RBCs antihemolytic assay and an in vivo sub-chronic oral toxicity method. Antidiabetic activity was evaluated using an in vitro α-amylase inhibition assay and in vivo using a chemically induced diabetic rat model. RESULTS The HPLC-UV analysis revealed the presence of p-hydroxybenzoic acid, p-hydroxybenzoic acid derivative, catechin, five catechin derivatives, epicatechin, isoquercetin, hyperoside, rutin, four quercetin derivatives, caffeic acid, and four caffeic acid derivatives in the polyherbal mixture decoction. Treatment with the decoction has shown no toxic effects. The antioxidant and cytoprotective activities of the polyherbal mixture were higher than the reference's ones. Its antidiabetic activity was high in both in vitro and in vivo studies. Fourteen days of treatment with the decoction (15 g/kg) completely normalized blood glucose levels of diabetic animals, while treatments with insulin and glimepiride only slightly lowered glycemic values. In addition, lipid status of treated animals as well as levels of serum AST, ALT, ALP, creatinine, urea and MDA were completely normalized. In addition, the polyherbal mixture completely restored the histopathological changes of the liver, kidneys and all four Cornu ammonis regions of the hippocampus. CONCLUSIONS The polyherbal mixture was effective in the prevention of both primary and secondary diabetic complications such as hyperlipidemia, increased lipid peroxidation, non-alcoholic fatty liver disease, nephropathy and neurodegeneration.
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Affiliation(s)
- Aleksandra Petrović
- Department of Biology and Ecology, Faculty of Sciences and Mathematics, University of Niš, Višegradska 33, 18000, Niš, Serbia.
| | - Višnja Madić
- Department of Biology and Ecology, Faculty of Sciences and Mathematics, University of Niš, Višegradska 33, 18000, Niš, Serbia
| | - Gordana Stojanović
- Department of Chemistry, Faculty of Sciences and Mathematics, University of Niš, Višegradska 33, 18000, Niš, Serbia
| | - Ivana Zlatanović
- Department of Chemistry, Faculty of Sciences and Mathematics, University of Niš, Višegradska 33, 18000, Niš, Serbia
| | - Bojan Zlatković
- Department of Biology and Ecology, Faculty of Sciences and Mathematics, University of Niš, Višegradska 33, 18000, Niš, Serbia
| | - Perica Vasiljević
- Department of Biology and Ecology, Faculty of Sciences and Mathematics, University of Niš, Višegradska 33, 18000, Niš, Serbia
| | - Ljubiša Đorđević
- Department of Biology and Ecology, Faculty of Sciences and Mathematics, University of Niš, Višegradska 33, 18000, Niš, Serbia
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Zhang R, Zhou X, Sheng Q, Zhang Q, Xie T, Xu C, Zou Z, Dong J, Liao L. Gliquidone ameliorates hepatic insulin resistance in streptozotocin-induced diabetic Sur1 -/- rats. Eur J Pharmacol 2021; 906:174221. [PMID: 34081903 DOI: 10.1016/j.ejphar.2021.174221] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2020] [Revised: 05/25/2021] [Accepted: 05/28/2021] [Indexed: 11/17/2022]
Abstract
Gliquidone was suggested to exert hypoglycemic effect through enhancing hepatic insulin sensitivity. However, inadequate in vivo evidences make this statement controversial. The aim of the present study was to clarify the insulin-sensitizer role of gliquidone in liver and muscle, so as to confirm its extra-pancreatic effects in vivo. TALEN technique was used to create Sur1 knockout (Sur1-/-) rats. Diabetic Sur1-/- rat models were established by high-fat diet combined with streptozotocin, and which were randomly divided into three groups: gliquidone, metformin and saline, treated for 8 weeks. Fasting blood glucose (FBG) and body mass were tested each week. IPGTT, IPITT and hyperinsulinemic-euglycemic clamp tests were used to evaluate glucose tolerance and insulin sensitivity, respectively. Key mediators of glucose metabolism in liver and skeletal muscle and the activity of AKT and AMPK in these tissues were further analyzed. We found that gliquidone decreased FBG and increased insulin sensitivity without increasing insulin secretion in diabetic Sur1-/- rats. Further exploration implied that gliquidone mainly increased hepatic glycogen storage and decreased gluconeogenesis, which were accompanied with activation of AKT, but not enhanced muscle GLUT4 expression. However, both these effects were still weaker than that of metformin. These results suggested that gliquidone could exerts an extra-pancreatic hypoglycemic effect by improving insulin sensitivity, which might be largely attributes to its additional insulin sensitizer role in hepatic glucose metabolism.
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Affiliation(s)
- Rui Zhang
- Division of Endocrinology, Department of Endocrinology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China
| | - Xiaojun Zhou
- Department of Endocrinology and Metabology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Key Laboratory of Rheumatic Disease and Translational Medicine, Shandong Institute of Nephrology, Laboratory of Endocrinology, Jinan, 250014, China; Division of Endocrinology, Department of Internal Medicine, Shandong Qianfoshan Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250014, China
| | - Qiqi Sheng
- Division of Endocrinology, Department of Endocrinology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China
| | - Qian Zhang
- Department of Pharmacology, Key Laboratory of Chemical Biology (Ministry of Education), School of Pharmaceutical Sciences, Shandong University, Jinan, Shandong, China
| | - Tianyue Xie
- Division of Endocrinology, Department of Endocrinology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China
| | - Chunmei Xu
- Department of Endocrinology and Metabology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Key Laboratory of Rheumatic Disease and Translational Medicine, Shandong Institute of Nephrology, Laboratory of Endocrinology, Jinan, 250014, China; Division of Endocrinology, Department of Internal Medicine, Shandong Qianfoshan Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250014, China
| | - Zhiwei Zou
- Division of Endocrinology, Yantai Affiliated Hospital of Binzhou Medical University, Yantai, 264117, China
| | - Jianjun Dong
- Division of Endocrinology, Department of Endocrinology, Qilu Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250012, China.
| | - Lin Liao
- Department of Endocrinology and Metabology, The First Affiliated Hospital of Shandong First Medical University & Shandong Provincial Qianfoshan Hospital, Shandong Key Laboratory of Rheumatic Disease and Translational Medicine, Shandong Institute of Nephrology, Laboratory of Endocrinology, Jinan, 250014, China; Division of Endocrinology, Department of Internal Medicine, Shandong Qianfoshan Hospital, Cheeloo College of Medicine, Shandong University, Jinan, 250014, China.
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Adaptations in GLUT4 Expression in Response to Exercise Detraining Linked to Downregulation of Insulin-Dependent Pathways in Cardiac but not in Skeletal Muscle Tissue. Int J Sport Nutr Exerc Metab 2020; 30:272-279. [PMID: 32454459 DOI: 10.1123/ijsnem.2019-0337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 03/27/2020] [Accepted: 03/27/2020] [Indexed: 11/18/2022]
Abstract
Insulin resistance is associated with cardiometabolic risk factors, and exercise training can improve insulin-mediated glucose uptake. However, few studies have demonstrated the reversibility of exercise-induced benefits. Thus, the authors examine the time-response effects of exercise training and detraining on glucose transporter 4 (GLUT4) content, insulin-dependent and insulin-independent pathways in cardiac and gastrocnemius muscle tissues of spontaneously hypertensive rats. Thirty-two male spontaneously hypertensive rats, 4 months old, were assigned to (n = 8/group): T (exercise training: 10-week treadmill exercise, 50-70% maximum effort capacity, 1 hr/day, 5 days/week); D2 (exercise training + 2-day detraining), D4 (exercise training + 4-day detraining); and S (no exercise). The authors evaluated insulin resistance, maximum effort capacity, GLUT4 content, p-IRS-1Tyr1179, p-AS160Ser588, p-AMPKα1Thr172, and p-CaMKIIThr286 in cardiac and gastrocnemius muscle tissues (Western blot). In response to exercise training, there were improvements in insulin resistance (15.4%; p = .010), increased GLUT4 content (microsomal, 29.4%; p = .012; plasma membrane, 27.1%; p < .001), p-IRS-1 (42.2%; p < .001), p-AS160 (60.0%; p < .001) in cardiac tissue, and increased GLUT4 content (microsomal, 29.4%; p = .009; plasma membrane, 55.5%; p < .001), p-IRS-1 (28.1%; p = .018), p-AS160 (76.0%; p < .001), p-AMPK-α1 (37.5%; p = .026), and p-CaMKII (30.0%; p = .040) in the gastrocnemius tissue. In D4 group, the exercise-induced increase in GLUT4 was reversed (plasma membrane, -21.3%; p = .027), p-IRS1 (-37.1%; p = .008), and p-AS160 (-82.6%; p < .001) in the cardiac tissue; p-AS160 expression (-35.7%; p = .034) was reduced in the gastrocnemius. In conclusion, the cardiac tissue is more susceptible to exercise adaptations in the GLUT4 content and signaling pathways than the gastrocnemius muscle. This finding may be explained by particular characteristics of insulin-dependent and insulin-independent pathways in the muscle tissues studied.
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Mori RC, Poças da Silva T, Campello RS, Machado UF. Carbenoxolone enhances peripheral insulin sensitivity and GLUT4 expression in skeletal muscle of obese rats: Potential participation of UBC9 protein. Life Sci 2019; 229:157-165. [PMID: 31077719 DOI: 10.1016/j.lfs.2019.05.017] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2019] [Revised: 05/06/2019] [Accepted: 05/07/2019] [Indexed: 01/06/2023]
Abstract
AIM This study investigates the insulin sensitizer effect of carbenoxolone (CBX) and potentially involved peripheral mechanisms. MAIN METHODS Taking glucose transporter 4 (GLUT4) as a marker of glucose disposal, we investigated the CBX effects on whole-body insulin sensitivity and solute carrier 2a4 (Slc2a4)/GLUT4 expression in visceral (VAT) and subcutaneous (SAT) adipose tissues and soleus muscle of monosodium glutamate (MSG)-induced obese rats. Sterol regulatory element binding protein (SREBP1), an enhancer of Slc2a4 expression was analyzed through mRNA content and SREBP1-binding to Slc2a4 promoter. Finally, the small ubiquitin-modifier conjugating enzyme 9 (UBC9), whose low content indicates accelerated GLUT4 degradation was analyzed in soleus. KEY FINDINGS Hypercorticosteronemia, hyperinsulinemia and low glucose decay rate in the insulin tolerance test of obese rats were restored by CBX (P < 0.05). Slc2a4/GLUT4 increased in SAT (P < 0.05) and decreased in VAT (P < 0.01) of obese rats. In soleus, obesity increased Slc2a4 but decreased GLUT4 (P < 0.01), possibly by accelerating GLUT4 degradation, as suggested by decreased UBC9 (P < 0.01). CBX restored both UBC9 and GLUT4 contents. SREBP1 did not participate in the Slc2a4 transcriptional regulation. SIGNIFICANCE The insulin sensitizer effect of CBX involves the increase of GLUT4 expression in soleus, indicating an increased glucose disposal in skeletal muscle. This observation reinforces the skeletal muscle as the main site of insulin-induced glucose uptake and sheds new light on the metabolic effects of 11βHSD1 inhibitors, since most of the studies so far have focused on its effects on liver and adipose tissues.
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Affiliation(s)
- Rosana Cristina Mori
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil.
| | - Thaís Poças da Silva
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Raquel Saldanha Campello
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil
| | - Ubiratan Fabres Machado
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Sao Paulo, SP, Brazil
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Chen YH, Li HZ, Tang ZS, Xu L, Wang H, Feng B. Efficacy and Safety of Premixed Human Insulin Combined with Sulfonylureas in Type 2 Diabetic Patients Previously Poorly Controlled with Insulin. Diabetes Ther 2019; 10:463-471. [PMID: 30659420 PMCID: PMC6437249 DOI: 10.1007/s13300-019-0564-z] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/16/2018] [Indexed: 01/31/2023] Open
Abstract
INTRODUCTION Some type 2 diabetes (T2DM) patients treated with premixed insulin alone or in combination with oral glucose-lowering agents (without sulfonylureas) cannot reach the required glucose targets. Clinical studies have demonstrated that diabetes patients treated with sulfonylureas achieve stable glycemic control, with a low hypoglycemic rate. The aim of our study was to evaluate the efficacy and safety of therapy with the combination of premixed insulin and sulfonylureas. METHODS A total of 120 patients with T2DM who were unable to achieve glycemic control on premixed human insulin were randomized into four groups, namely, a control group (premixed human insulin only) and three groups receiving combination therapy with premixed human insulin and one of the following sulfonylureas: gliclazide sustained release tablets [Diamicron], glipizide extended release tablets [Glucotrol XL], and glimepiride medium-to-long-acting tablets [Amaryl], with 30 patients in each group. Hemoglobin A1c, blood glucose, and adverse events were assessed at baseline and at the end of the 12-week treatment period. RESULTS After treatment for 12 weeks, HbA1c, fasting glucose, and 2-h postprandial glucose levels in the four groups were significantly decreased when compared with baseline (P < 0.05). However, there was no difference between the four groups at the end of the study. In the control group, the daily insulin dose had been significantly increased at the end of the follow-up when compared with baseline (P < 0.05), while there were no significant changes in premixed insulin dose in the three combination therapy groups. There were no significant differences in adverse events among the four groups. CONCLUSION Insulin combined with sulfonylureas could improve glycemic control without increasing daily insulin dose and adverse events. Based on our results, we consider the combination of premixed insulin and sulfonylureas to be effective and safe for the treatment of T2DM. TRIAL REGISTRATION This trial was registered as ChiCTR-TRC-14004751. Trial Registration Date: 5 June 2014.
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Affiliation(s)
- Ying-Hua Chen
- Department of Endocrinology, East Hospital, Tongji University, Shanghai, 200120, People's Republic of China
| | - Hui-Zhi Li
- Department of Endocrinology, East Hospital, Tongji University, Shanghai, 200120, People's Republic of China
| | - Zhao-Sheng Tang
- Department of Endocrinology, East Hospital, Tongji University, Shanghai, 200120, People's Republic of China
| | - Lei Xu
- Department of Endocrinology, East Hospital, Tongji University, Shanghai, 200120, People's Republic of China
| | - Hua Wang
- Department of Endocrinology, East Hospital, Tongji University, Shanghai, 200120, People's Republic of China.
| | - Bo Feng
- Department of Endocrinology, East Hospital, Tongji University, Shanghai, 200120, People's Republic of China.
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Zhou X, Zhang R, Zou Z, Shen X, Xie T, Xu C, Dong J, Liao L. Hypoglycaemic effects of glimepiride in sulfonylurea receptor 1 deficient rat. Br J Pharmacol 2018; 176:478-490. [PMID: 30471094 DOI: 10.1111/bph.14553] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2018] [Revised: 10/30/2018] [Accepted: 11/02/2018] [Indexed: 02/06/2023] Open
Abstract
BACKGROUND AND PURPOSE Sulfonylureas (SUs) have been suggested to have an insulin-independent blood glucose-decreasing activity due to an extrapancreatic effect. However, a lack of adequate in vivo evidence makes this statement controversial. Here, we aimed to evaluate whether glimepiride has extrapancreatic blood glucose-lowering activity in vivo. EXPERIMENTAL APPROACH Sulfonylurea receptor 1 deficient (SUR1-/- ) rats were created by means of transcription activator-like effector nucleases (TALEN)-mediated gene targeting technology. Type 2 diabetic models were established by feeding a high-fat diet and administering a low-dose of streptozotocin. These rats were then randomly divided into four groups: glimepiride, gliclazide, metformin and saline. All rats were treated for 2 weeks. KEY RESULTS Glimepiride decreased blood glucose levels and increased insulin sensitivity without elevating insulin levels. Gliclazide showed similar effects as glimepiride. Both agents were weaker than metformin. Further mechanistic investigations revealed that glimepiride increased hepatic glycogen synthesis and decreased gluconeogenesis, which were accompanied by the activation of Akt in the liver. Moreover, glimepiride increased both total and membrane glucose transporter 4 (GLUT4) levels in muscle and fat, which might be attributed to insulin receptor-independent IRS1/Akt activation. CONCLUSION AND IMPLICATIONS Glimepiride possesses an extrapancreatic blood glucose-lowering effect in vivo, which might be attributed to its direct effect on insulin-sensitive tissues. Therefore, the combination of glimepiride with multiple insulin injections should not be excluded per se.
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Affiliation(s)
- Xiaojun Zhou
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
| | - Rui Zhang
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
| | - Zhiwei Zou
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, China
| | - Xue Shen
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Tianyue Xie
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University of Traditional Chinese Medicine, Jinan, China
| | - Chunmei Xu
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
| | - Jianjun Dong
- Department of Endocrinology, Qilu Hospital of Shandong University, Jinan, China
| | - Lin Liao
- Department of Endocrinology, Shandong Provincial Qianfoshan Hospital, Shandong University, Jinan, China
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Dresseno LP, Lehnen AM, Teló G, Silveira A, Markoski MM, Machado UF, Schaan BD. Impact of flaxseed and soy nuts as dietary supplements on lipid profile, insulin sensitivity, and GLUT4 expression in ovariectomized rats. Appl Physiol Nutr Metab 2018; 43:1282-1287. [PMID: 29806984 DOI: 10.1139/apnm-2018-0137] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022]
Abstract
We assessed the effects of a diet with flaxseed or soy nuts versus estradiol on the lipid profile, insulin sensitivity, and glucose transporter type 4 (GLUT4) expression in ovariectomized female rats. Forty-four female Wistar rats (90 days old) underwent ovariectomy and were divided into 4 groups: C (standard diet), E (standard diet + subcutaneous 17β-estradiol pellets), L (standard diet + flaxseed + subcutaneous placebo pellets), and S (standard diet + soy nuts + subcutaneous placebo pellets). Customized diets and the insertion of pellets were started 21 days after ovariectomy and were continued for another 21 days. We measured body mass, insulin tolerance, total cholesterol, low-density lipoprotein cholesterol, high-density lipoprotein cholesterol, triglycerides, and GLUT4 (in cardiac and adipose tissues). We found a lower body mass and a lower Lee index in group E and a trend toward improved insulin sensitivity in group S (p = 0.066). Groups L and S showed a better lipid profile when compared with group C. Microsomal GLUT4 increased in group L (in cardiac and adipose tissues), and plasma membrane GLUT4 increased in groups E, L, and S (in both tissues). We conclude that flaxseed and soy nuts as dietary supplements improve lipid profile and increase GLUT4 expression.
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Affiliation(s)
- Luciana P Dresseno
- a Endocrine Division, Hospital de Clínicas de Porto Alegre/Universidade Federal do Rio Grande do Sul, Rua Ramiro Barcelos, 2350. CEP 90035-003 - Porto Alegre, RS, Brazil
- b Instituto de Cardiologia do Rio Grande do Sul/Fundação Universitária de Cardiologia, Porto Alegre 90620-001, Brazil
| | - Alexandre M Lehnen
- b Instituto de Cardiologia do Rio Grande do Sul/Fundação Universitária de Cardiologia, Porto Alegre 90620-001, Brazil
| | - Gabriela Teló
- d Endocrine Division, Hospital de Clínicas de Porto Alegre/Universidade Federal do Rio Grande do Sul, Porto Alegre 90620-001, Brazil
| | - Ariel Silveira
- b Instituto de Cardiologia do Rio Grande do Sul/Fundação Universitária de Cardiologia, Porto Alegre 90620-001, Brazil
| | - Melissa M Markoski
- b Instituto de Cardiologia do Rio Grande do Sul/Fundação Universitária de Cardiologia, Porto Alegre 90620-001, Brazil
| | - Ubiratan F Machado
- c Instituto de Ciências Biomédicas, Universidade de São Paulo, São Paulo 05508-900, Brazil
| | - Beatriz D Schaan
- d Endocrine Division, Hospital de Clínicas de Porto Alegre/Universidade Federal do Rio Grande do Sul, Porto Alegre 90620-001, Brazil
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Niedowicz DM, Özcan S, Nelson PT. Glimepiride Administered in Chow Reversibly Impairs Glucose Tolerance in Mice. J Diabetes Res 2018; 2018:1251345. [PMID: 30510962 PMCID: PMC6231393 DOI: 10.1155/2018/1251345] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2018] [Revised: 09/12/2018] [Accepted: 09/20/2018] [Indexed: 12/04/2022] Open
Abstract
Sulfonylureas are a class of antidiabetes medications prescribed to millions of individuals worldwide. Rodents have been used extensively to study sulfonylureas in the laboratory. Here, we report the results of studies treating mice with a sulfonylurea (glimepiride) in order to understand how the drug affects glucose homeostasis and tolerance. We tested the effect of glimepiride on fasting blood glucose, glucose tolerance, and insulin secretion, using glimepiride sourced from a local pharmacy. We also examined the effect on glucagon, gluconeogenesis, and insulin sensitivity. Unexpectedly, glimepiride exposure in mice was associated with fasting hyperglycemia, glucose intolerance, and decreased insulin. There was no change in circulating glucagon levels or gluconeogenesis. The effect was dose-dependent, took effect by two weeks, and was reversed within three weeks after removal. Glimepiride elicited the same effects in all strains evaluated: four wild-type strains, as well as the transgenic Grn-/- and diabetic db/db mice. Our findings suggest that the use of glimepiride as a hypoglycemic agent in mice should proceed with caution and may have broader implications about mouse models as a proxy to study the human pharmacopeia.
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Affiliation(s)
- Dana M. Niedowicz
- Sanders Brown Center on Aging, University of Kentucky, Lexington, KY 40536, USA
| | - Sabire Özcan
- Department of Molecular and Cellular Biochemistry, University of Kentucky, Lexington, KY 40506, USA
| | - Peter T. Nelson
- Sanders Brown Center on Aging, University of Kentucky, Lexington, KY 40536, USA
- Department of Pathology, University of Kentucky, Lexington, KY 40506, USA
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Advanced glycation end products-induced insulin resistance involves repression of skeletal muscle GLUT4 expression. Sci Rep 2018; 8:8109. [PMID: 29802324 PMCID: PMC5970140 DOI: 10.1038/s41598-018-26482-6] [Citation(s) in RCA: 41] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 05/14/2018] [Indexed: 11/08/2022] Open
Abstract
Little is known about advanced glycation end products (AGEs) participation in glucose homeostasis, a process in which skeletal muscle glucose transporter GLUT4 (Scl2a4 gene) plays a key role. This study investigated (1) the in vivo and in vitro effects of AGEs on Slc2a4/GLUT4 expression in skeletal muscle of healthy rats, and (2) the potential involvement of endoplasmic reticulum and inflammatory stress in the observed regulations. For in vivo analysis, rats were treated with advanced glycated rat albumin (AGE-albumin) for 12 weeks; for in vitro analysis, soleus muscles from normal rats were incubated with bovine AGE-albumin for 2.5 to 7.5 hours. In vivo, AGE-albumin induced whole-body insulin resistance; decreased (~30%) Slc2a4 mRNA and GLUT4 protein content; and increased (~30%) the nuclear content of nuclear factor NF-kappa-B p50 subunit (NFKB1), and cellular content of 78 kDa glucose-regulated protein (GRP78). In vitro, incubation with AGE-albumin decreased (~50%) the Slc2a4/GLUT4 content; and increased cellular content of GRP78/94, phosphorylated-IKK-alpha/beta, nuclear content of NFKB1 and RELA, and the nuclear protein binding into Slc2a4 promoter NFKB-binding site. The data reveal that AGEs impair glucose homeostasis in non-diabetic states of increased AGEs concentration; an effect that involves activation of endoplasmic reticulum- and inflammatory-stress and repression of Slc2a4/GLUT4 expression.
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Frederico MJS, Castro AJG, Pinto VAM, Ramos CDF, Monteiro FBF, Mascarello A, Nunes RJ, Silva FRMB. Mechanism of action of camphoryl-benzene sulfonamide derivative on glucose uptake in adipose tissue. J Cell Biochem 2018; 119:4408-4419. [PMID: 29130561 DOI: 10.1002/jcb.26506] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2017] [Accepted: 11/09/2017] [Indexed: 11/09/2022]
Abstract
The aim of the present study was to investigate the mechanism of action of a sulfonamide derivative on glucose uptake in adipose tissue, as well as to characterize the effects of this compound on intestinal disaccharidases and advanced glycation end-products (AGEs) formation. Camphoryl-benzene sulfonamide (CS) was able to stimulate glucose uptake in isolated adipocytes, adipose tissue, and in soleus muscle. The stimulatory effect of the compound (10 μM) on glucose uptake on adipose tissue was blocked by diazoxide, wortmannin, U73122, colchicine, and N-ethylmaleimide. On the other hand, the effects of CS were not blocked by glibenclamide, an inhibitor of the K+ -ATP channel, or even by the inhibitor of protein p38 MAPK, SB 203580. In vivo, this compound reduced intestinal disaccharidase activity, while, in vitro, CS reduced the formation of AGEs at 7, 14, and 28 days of incubation. The stimulatory effect of CS on glucose uptake requires the activation of the K+ -ATP channel, translocation, and fusion of GLUT4 vesicles to the plasma membrane on adipocytes for glucose homeostasis. In addition, the inhibition of disaccharidase activity contributes to the glucose homeostasis in a short-term as well as the remarkable reduction in AGE formation indicates that the CS may prevent of complications of late diabetes.
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Affiliation(s)
- Marisa J S Frederico
- Departamento de Bioquímica-Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Allisson J G Castro
- Departamento de Bioquímica-Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
| | - Veronica A M Pinto
- Departamento de Anatomia, Universidade Estadual do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Cristiane D F Ramos
- Departamento de Anatomia, Universidade Estadual do Rio de Janeiro, Rio de Janeiro, Brazil
| | - Fabíola B F Monteiro
- Departamento de Análises Clínicas-Centro de Ciências da Saúde, Universidade Federal de Santa Catarina, Brazil
| | - Alessandra Mascarello
- Departamento de Química, Centro de Ciências Físicas e Matemáticas, Campus Universitário, Bairro Trindade, Florianópolis, Santa Catarina, Brazil
| | - Ricardo J Nunes
- Departamento de Química, Centro de Ciências Físicas e Matemáticas, Campus Universitário, Bairro Trindade, Florianópolis, Santa Catarina, Brazil
| | - Fátima R M B Silva
- Departamento de Bioquímica-Centro de Ciências Biológicas, Universidade Federal de Santa Catarina, Florianópolis, Brazil
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Halmenschlager L, Lehnen AM, Marcadenti A, Markoski MM. Omega-3 Fatty Acids Supplementation Differentially Modulates the SDF-1/CXCR-4 Cell Homing Axis in Hypertensive and Normotensive Rats. Nutrients 2017; 9:E826. [PMID: 28763008 PMCID: PMC5579619 DOI: 10.3390/nu9080826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2017] [Revised: 07/24/2017] [Accepted: 07/27/2017] [Indexed: 11/16/2022] Open
Abstract
BACKGROUND We assessed the effect of acute and chronic dietary supplementation of ω-3 on lipid metabolism and cardiac regeneration, through its influence on the Stromal Derived Factor-1 (SDF-1) and its receptor (CXCR4) axis in normotensive and hypertensive rats. METHODS Male Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR) were allocated in eight groups (of eight animals each), which received daily orogastric administration of ω-3 (1 g) for 24 h, 72 h or 2 weeks. Blood samples were collected for the analysis of the lipid profile and SDF-1 systemic levels (ELISA). At the end of the treatment period, cardiac tissue was collected for CXCR4 expression analysis (Western blot). RESULTS The use of ω-3 caused a reduction in total cholesterol levels (p = 0.044), and acutely activated the SDF-1/CXCR4 axis in normotensive animals (p = 0.037). In the presence of the ω-3, after 72 h, SDF-1 levels decreased in WKY and increased in SHR (p = 0.017), and tissue expression of the receptor CXCR4 was higher in WKY than in SHR (p = 0.001). CONCLUSION The ω-3 fatty acid supplementation differentially modulates cell homing mediators in normotensive and hypertensive animals. While WKY rats respond acutely to omega-3 supplementation, showing increased release of SDF-1 and CXCR4, SHR exhibit a weaker, delayed response.
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Affiliation(s)
- Luiza Halmenschlager
- Postgraduate Program in Health Sciences: Cardiology, Institute of Cardiology of Rio Grande do Sul/University Foundation of Cardiology (IC/FUC), Princesa Isabel Avenue, 370, Porto Alegre, RS 90620-001, Brazil.
| | - Alexandre Machado Lehnen
- Postgraduate Program in Health Sciences: Cardiology, Institute of Cardiology of Rio Grande do Sul/University Foundation of Cardiology (IC/FUC), Princesa Isabel Avenue, 370, Porto Alegre, RS 90620-001, Brazil.
- Laboratory of Biodynamics, Sogipa School of Physical Education, Benjamin Constant Avenue, 80, Porto Alegre RS 90550-003, Brazil.
| | - Aline Marcadenti
- Postgraduate Program in Health Sciences: Cardiology, Institute of Cardiology of Rio Grande do Sul/University Foundation of Cardiology (IC/FUC), Princesa Isabel Avenue, 370, Porto Alegre, RS 90620-001, Brazil.
- Postgraduate Program in Nutrition Sciences, Federal University of Health Sciences of Porto Alegre (UFCSPA), Sarmento Leite Avenue, 245, Porto Alegre RS 90050-170, Brazil.
| | - Melissa Medeiros Markoski
- Postgraduate Program in Health Sciences: Cardiology, Institute of Cardiology of Rio Grande do Sul/University Foundation of Cardiology (IC/FUC), Princesa Isabel Avenue, 370, Porto Alegre, RS 90620-001, Brazil.
- Postgraduate Program in Nutrition Sciences, Federal University of Health Sciences of Porto Alegre (UFCSPA), Sarmento Leite Avenue, 245, Porto Alegre RS 90050-170, Brazil.
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Resveratrol Improves Glycemic Control in Type 2 Diabetic Obese Mice by Regulating Glucose Transporter Expression in Skeletal Muscle and Liver. Molecules 2017; 22:molecules22071180. [PMID: 28708105 PMCID: PMC6152102 DOI: 10.3390/molecules22071180] [Citation(s) in RCA: 43] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2017] [Revised: 07/05/2017] [Accepted: 07/06/2017] [Indexed: 01/10/2023] Open
Abstract
Insulin resistance participates in the glycaemic control disruption in type 2 diabetes mellitus (T2DM), by reducing muscle glucose influx and increasing liver glucose efflux. GLUT4 (Slc2a4 gene) and GLUT2 (Slc2a2 gene) proteins play a fundamental role in the muscle and liver glucose fluxes, respectively. Resveratrol is a polyphenol suggested to have an insulin sensitizer effect; however, this effect, and related mechanisms, have not been clearly demonstrated in T2DM. We hypothesized that resveratrol can improve glycaemic control by restoring GLUT4 and GLUT2 expression in muscle and liver. Mice were rendered obese T2DM in adult life by neonatal injection of monosodium glutamate. Then, T2DM mice were treated with resveratrol for 60 days or not. Glycaemic homeostasis, GLUT4, GLUT2, and SIRT1 (sirtuin 1) proteins (Western blotting); Slc2a4, Slc2a2, and Pck1 (key gluconeogenic enzyme codifier) mRNAs (RT-qPCR); and hepatic glucose efflux were analysed. T2DM mice revealed: high plasma concentration of glucose, fructosamine, and insulin; insulin resistance (insulin tolerance test); decreased Slc2a4/GLUT4 content in gastrocnemius and increased Slc2a2/GLUT2 content in liver; and increased Pck1 mRNA and gluconeogenic activity (pyruvate tolerance test) in liver. All alterations were restored by resveratrol treatment. Additionally, in both muscle and liver, resveratrol increased SIRT1 nuclear content, which must participate in gene expression regulations. In sum, the results indisputably reveals that resveratrol improves glycaemic control in T2DM, and that involves an increase in muscle Slc2a4/GLUT4 and a decrease in liver Slc2a2/GLUT2 expression. This study contributes to our understanding how resveratrol might be prescribed for T2DM according to the principles of evidence-based medicine.
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Esteves JV, Enguita FJ, Machado UF. MicroRNAs-Mediated Regulation of Skeletal Muscle GLUT4 Expression and Translocation in Insulin Resistance. J Diabetes Res 2017; 2017:7267910. [PMID: 28428964 PMCID: PMC5385897 DOI: 10.1155/2017/7267910] [Citation(s) in RCA: 66] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/19/2016] [Revised: 02/22/2017] [Accepted: 02/27/2017] [Indexed: 01/12/2023] Open
Abstract
The solute carrier family 2 facilitated glucose transporter member 4 (GLUT4) plays a key role in the insulin-induced glucose uptake by muscle and adipose tissues. In prediabetes and diabetes, GLUT4 expression/translocation has been detected as reduced, participating in mechanisms that impair glycemic control. Recently, a class of short endogenous noncoding RNAs named microRNAs (miRNAs) has been increasingly described as involved in the posttranscriptional epigenetic regulation of gene expression. The present review focuses on miRNAs potentially involved in the expression of GLUT4 expression, and proteins related to GLUT4 and translocation in skeletal muscle, seeking to correlate them with insulin resistance and diabetes. So far, miR-21a-5p, miR-29a-3p, miR-29c-3p, miR-93-5p, miR-106b-5p, miR-133a-3p, miR-133b-3p, miR-222-3p, and miR-223-3p have been reported to directly and/or indirectly regulate the GLUT4 expression; and their expression is altered under diabetes-related conditions. Besides, some miRNAs that have been linked to the expression of proteins involved in GLUT4 translocation machinery in muscle could also impact glucose uptake. That makes these miRNAs promising targets for preventive and/or therapeutic approaches, which could improve glycemic control, thus deserving future new investigations.
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Affiliation(s)
- João Victor Esteves
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
| | - Francisco Javier Enguita
- Instituto de Medicina Molecular, Faculdade de Medicina, Universidade de Lisboa, 1649-028 Lisboa, Portugal
| | - Ubiratan Fabres Machado
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, São Paulo, SP, Brazil
- *Ubiratan Fabres Machado:
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15
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Kalra S, Aamir AH, Raza A, Das AK, Azad Khan AK, Shrestha D, Qureshi MF, Md Fariduddin, Pathan MF, Jawad F, Bhattarai J, Tandon N, Somasundaram N, Katulanda P, Sahay R, Dhungel S, Bajaj S, Chowdhury S, Ghosh S, Madhu SV, Ahmed T, Bulughapitiya U. Place of sulfonylureas in the management of type 2 diabetes mellitus in South Asia: A consensus statement. Indian J Endocrinol Metab 2015; 19:577-96. [PMID: 26425465 PMCID: PMC4566336 DOI: 10.4103/2230-8210.163171] [Citation(s) in RCA: 65] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/22/2022] Open
Abstract
Since their introduction in clinical practice in the 1950's, Sulfonylureas (SUs) have remained the main-stay of pharmacotherapy in the management of type 2 diabetes. Despite their well-established benefits, their place in therapy is inappropriately being overshadowed by newer therapies. Many of the clinical issues associated with the use of SUs are agent-specific, and do not pertain to the class as such. Modern SUs (glimepiride, gliclazide MR) are backed by a large body of evidence, experience, and most importantly, outcome data, which supports their role in managing patients with diabetes. Person-centred care, i.e., careful choice of SU, appropriate dosage, timing of administration, and adequate patient counseling, will ensure that deserving patients are not deprived of the advantages of this well-established class of anti-diabetic agents. Considering their efficacy, safety, pleiotropic benefits, and low cost of therapy, SUs should be considered as recommended therapy for the treatment of diabetes in South Asia. This initiative by SAFES aims to encourage rational, safe and smart prescription of SUs, and includes appropriate medication counseling.
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Affiliation(s)
- Sanjay Kalra
- Department of Endocrinology, Bharti Hospital and BRIDE, Karnal, Haryana, India
| | - A H Aamir
- Department of Endocrinology, Post Graduate Medical Institute Hayatabad Medical Complex, Peshawar, Pakistan
| | - Abbas Raza
- Shaukat Khanum Memorial Cancer Hospital and Research Centre, Lahore, Pakistan
| | - A K Das
- Department of Endocrinology, Pondicherry Institute of Medical Sciences, Puducherry, India
| | - A K Azad Khan
- Department of Public Health, Bangladesh University of Health Sciences, Dhaka, Bangladesh
| | - Dina Shrestha
- Department of Endocrinology, Norvic International Hospital, Kathmandu, Nepal
| | - Md Faisal Qureshi
- Department of Endocrinology, Al-Khaliq Medicare Hospital, Dhaka, Bangladesh
| | - Md Fariduddin
- Department of Endocrinology, Bangabandhu Sheikh Mujib Medical University, Shahbag, Dhaka, Bangladesh
| | | | - Fatema Jawad
- Department of Diabetology, Medilink Clinics, Karachi, Pakistan
| | - Jyoti Bhattarai
- Department of Medicine, Trivuvan University, Kathmandu, Nepal
| | - Nikhil Tandon
- Department of Endocrinology and Metabolism, All India Institute of Medical Sciences, Ansari Nagar, New Delhi, India
| | - Noel Somasundaram
- South Asian Federation of Endocrine Societies, National Hospital, Dhaka, Bangladesh
| | - Prasad Katulanda
- Department of Clinical Medicines, Diabetes Research Unit, University of Colombo, Colombo, Sri Lanka
| | - Rakesh Sahay
- Department of Endocrinology, Osmania Medical College, Hyderabad, Telangana, India
| | - Sanjib Dhungel
- Department of Medicine, Nepal Medical College Teaching Hospital, Kathmandu, Nepal
| | - Sarita Bajaj
- Department of Medicine, MLN Medical College, Allahabad, Uttar Pradesh, India
| | - Subhankar Chowdhury
- Department of Endocrinology, IPGMER and SSKM Hospital, Kolkata, West Bengal, India
| | - Sujoy Ghosh
- Department of Endocrinology and Metabolism, IPGMER, Kolkata, West Bengal, India
| | - S V Madhu
- Department of Medicine and Head, Centre for Diabetes, Endocrinology and Metabolism, UCMS-GTB Hospital, New Delhi, India
| | - Tofail Ahmed
- Department of Endocrinology, BIRDEM, Dhaka, Bangladesh
| | - Uditha Bulughapitiya
- Department of Endocrinology, Kalubowila South Teaching Hospital, Kalubowila, Sri Lanka
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Muscle IGF-1-induced skeletal muscle hypertrophy evokes higher insulin sensitivity and carbohydrate use as preferential energy substrate. BIOMED RESEARCH INTERNATIONAL 2015; 2015:282984. [PMID: 25722973 PMCID: PMC4334619 DOI: 10.1155/2015/282984] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2014] [Accepted: 01/22/2015] [Indexed: 01/03/2023]
Abstract
We characterized the metabolic profile of transgenic mice exhibiting enhanced muscle mass driven by increased mIGF-1 expression (MLC/mIGF-1). As expected, 6-month-old MLC/mIGF-1 mice were heavier than age-matched wild type (WT) mice (37.4 ± 0.3 versus 31.8 ± 0.6 g, resp.). MLC/mIGF-1 mice had higher respiratory quotient when compared to WT (0.9 ± 0.03 versus 0.74 ± 0.02, resp.) suggesting a preference for carbohydrate as the major fuel source. MLC/mIGF-1 mice had a higher rate of glucose disposal when compared to WT (3.25 ± 0.14 versus 2.39 ± 0.03%/min, resp.). The higher disposal rate correlated to ∼2-fold higher GLUT4 content in the extensor digitorum longus (EDL) muscle. Analysis of mRNA content for the glycolysis-related gene PFK-1 showed ∼3-fold upregulation in MLC/mIGF-1 animals. We also found a 50% downregulation of PGC1α mRNA levels in MLC/mIGF-1 mouse EDL muscle, suggesting less abundant mitochondria in this tissue. We found no difference in the expression of PPARα and PPARβ/δ, suggesting no modulation of key elements in oxidative metabolism. These data together suggest a shift in metabolism towards higher carbohydrate utilization, and that could explain the increased insulin sensitivity of hypertrophied skeletal muscle in MLC/mIGF-1 mice.
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Biochemical alterations during the obese-aging process in female and male monosodium glutamate (MSG)-treated mice. Int J Mol Sci 2014; 15:11473-94. [PMID: 24979131 PMCID: PMC4139794 DOI: 10.3390/ijms150711473] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2014] [Revised: 06/11/2014] [Accepted: 06/12/2014] [Indexed: 01/07/2023] Open
Abstract
Obesity, from children to the elderly, has increased in the world at an alarming rate over the past three decades, implying long-term detrimental consequences for individual’s health. Obesity and aging are known to be risk factors for metabolic disorder development, insulin resistance and inflammation, but their relationship is not fully understood. Prevention and appropriate therapies for metabolic disorders and physical disabilities in older adults have become a major public health challenge. Hence, the aim of this study was to evaluate inflammation markers, biochemical parameters and glucose homeostasis during the obese-aging process, to understand the relationship between obesity and health span during the lifetime. In order to do this, the monosodium glutamate (MSG) obesity mice model was used, and data were evaluated at 4, 8, 12, 16 and 20 months in both female and male mice. Our results showed that obesity was a major factor contributing to premature alterations in MSG-treated mice metabolism; however, at older ages, obesity effects were attenuated and MSG-mice became more similar to normal mice. At a younger age (four months old), the Lee index, triglycerides, total cholesterol, TNF-α and transaminases levels increased; while adiponectin decreased and glucose tolerance and insulin sensitivity levels were remarkably altered. However, from 16 months old-on, the Lee index and TNF-α levels diminished significantly, while adiponectin increased, and glucose and insulin homeostasis was recovered. In summary, MSG-treated obese mice showed metabolic changes and differential susceptibility by gender throughout life and during the aging process. Understanding metabolic differences between genders during the lifespan will allow the discovery of specific preventive treatment strategies for chronic diseases and functional decline.
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Shi FH, Wu Y, Dai DZ, Cong XD, Zhang YM, Dai Y. Hepatosteatosis and hepatic insulin resistance are blunted by argirein, an anti-inflammatory agent, through normalizing endoplasmic reticulum stress and apoptosis in diabetic liver. ACTA ACUST UNITED AC 2013; 65:916-27. [PMID: 23647685 DOI: 10.1111/jphp.12051] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2012] [Accepted: 02/11/2013] [Indexed: 12/28/2022]
Abstract
OBJECTIVES Insulin resistance represents a mechanism underlying defect metabolism of carbohydrate and lipid linked to inflammatory reactions in diabetic liver. We hypothesized that the changes may be secondary to endoplasmic reticulum (ER) stress, which could be alleviated by either argirein or valsartan. METHODS Hepatosteatosis in diabetic liver was induced in rats fed with a high-fat diet (HFD) for 12 weeks combined with a single low dose of streptozotocin (STZ 35 mg/kg, ip). Interventions (mg/kg/d, po)with either argirein (50, 100 and 200) or valsartan (12) were conducted in the last 4 weeks. KEY FINDINGS In diabetic liver fat was significantly accumulated in association with elevated hepatic glucose, serum insulin and homeostasis model assessment of insulin resistance value. Downregulated glucose transporter 4, insulin receptor substrate-1 and leptin receptor (P < 0.01) were found relative to normal, where DNA ladder, downregulated B cell lymphoma/leukemia-2, upregulated B cell lymphoma/leukemia-2 Associated X protein and upregulated ER stress chaperones such as Bip/GRP78 (also known as Binding Protein, BiP), PKR-like ER kinase (PERK), p-PERK/PERK and C/EBP homologous protein were significant. These abnormalities were significantly ameliorated by argirein and valsartan. CONCLUSIONS Hepatosteatosis induced by HFD/low STZ manifests insulin resistance and apoptosis, linked to an entity of low-grade inflammation due to activated ER stress sensors. With anti-inflammatory activity either argirein or valsartan blunts hepatosteatosis through normalizing ER stress and apoptosis in the diabetic liver.
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Affiliation(s)
- Fang-Hong Shi
- China Pharmaceutical University, Research Division of Pharmacology, Nanjing, China
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19
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Lehnen AM, Leguisamo NM, Casali KR, Schaan BD. Progressive cardiovascular autonomic dysfunction in rats with evolving metabolic syndrome. Auton Neurosci 2013; 176:64-9. [PMID: 23491326 DOI: 10.1016/j.autneu.2013.02.011] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2012] [Revised: 01/22/2013] [Accepted: 02/17/2013] [Indexed: 01/26/2023]
Abstract
Metabolic syndrome is linked to increased cardiovascular mortality, which may be partially attributed to cardiac sympatho-vagal imbalance. However, autonomic changes were not evaluated during the metabolic syndrome development in a monosodium glutamate-induced animal model. We evaluate temporal changes in cardiovascular autonomic modulation in an animal model of metabolic syndrome. Eighteen neonate male spontaneously hypertensive rats (SHR) were treated with monosodium glutamate (MetS), and compared with Wistar-Kyoto (C) and saline-treated SHR (H). Lee index, insulin resistance and autonomic control (spectral analysis) were evaluated at 3 (3-mo), 6 (6-mo) and 9 (9-mo) months of age (compared by two-way ANOVA, p<0.05). Weight of visceral fat, Lee index and arterial pressure were higher in the MetS vs. C and H groups (p<0.001) at all ages. Heart rate variability (HRV) was decreased in the MetS and H groups at 3-mo and 9-mo vs. C. The LF component of HRV was reduced in the MetS group at 3-mo vs. C (p=0.032), and higher vs. C and H at 9-mo (p<0.001, all comparisons). H and MetS rats had a higher LF/HF index vs. C at 9-mo (p=0.001, all comparisons). The VLF component of systolic arterial pressure variability of the MetS was higher earlier (6-mo) than that of the H group. A reduction of 70%, 98% and 54% in αLF index of H and MetS rats vs. C, was observed at 3, 6 and 9 months, respectively. Metabolic syndrome and hypertension in rats evolve with progressive autonomic dysfunction (worst at 9 months), with specific derangements occurring very early.
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Affiliation(s)
- A M Lehnen
- Instituto de Cardiologia do Rio Grande do Sul/Fundação Universitária de Cardiologia, Rio Grande do Sul, Brazil; Endocrine Division, Hospital de Clínicas de Porto Alegre, Universidade Federal do Rio Grande do Sul, Brazil.
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20
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Leguisamo NM, Lehnen AM, Machado UF, Okamoto MM, Markoski MM, Pinto GH, Schaan BD. GLUT4 content decreases along with insulin resistance and high levels of inflammatory markers in rats with metabolic syndrome. Cardiovasc Diabetol 2012; 11:100. [PMID: 22897936 PMCID: PMC3439702 DOI: 10.1186/1475-2840-11-100] [Citation(s) in RCA: 83] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2012] [Accepted: 07/11/2012] [Indexed: 02/07/2023] Open
Abstract
Background Metabolic syndrome is characterized by insulin resistance, which is closely related to GLUT4 content in insulin-sensitive tissues. Thus, we evaluated the GLUT4 expression, insulin resistance and inflammation, characteristics of the metabolic syndrome, in an experimental model. Methods Spontaneously hypertensive neonate rats (18/group) were treated with monosodium glutamate (MetS) during 9 days, and compared with Wistar-Kyoto (C) and saline-treated SHR (H). Blood pressure (BP) and lipid levels, C-reactive protein (CRP), interleukin 6 (IL-6), TNF-α and adiponectin were evaluated. GLUT4 protein was analysed in the heart, white adipose tissue and gastrocnemius. Studies were performed at 3 (3-mo), 6 (6-mo) and 9 (9-mo) months of age. Results MetS rats were more insulin resistant (p<0.001, all ages) and had higher BP (3-mo: p<0.001, 6-mo: p = 0.001, 9-mo: p = 0.015) as compared to C. At 6 months, CRP, IL-6 and TNF-α were higher (p<0.001, all comparisons) in MetS rats vs H, but adiponectin was lower in MetS at 9 months (MetS: 32 ± 2, H: 42 ± 2, C: 45 ± 2 pg/mL; p<0.001). GLUT4 protein was reduced in MetS as compared to C rats at 3, 6 and 9-mo, respectively (Heart: 54%, 50% and 57%; Gastrocnemius: 37%, 56% and 50%; Adipose tissue: 69%, 61% and 69%). Conclusions MSG-treated SHR presented all metabolic syndrome characteristics, as well as reduced GLUT4 content, which must play a key role in the impaired glycemic homeostasis of the metabolic syndrome.
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Affiliation(s)
- Natalia M Leguisamo
- Laboratório de Experimentação Animal e Laboratório de Cardiologia Molecular e Celular, Instituto de Cardiologia/Fundação, Universitária de Cardiologia, Bairro Santana, Porto Alegre, RS, Brazil
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21
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Machado HA, Vieira M, Cunha MR, Correia MRS, Fukui RT, Santos RFD, Rocha DM, Wajchenberg BL, Lage SG, Silva MERD. Metformin, but not glimepiride, improves carotid artery diameter and blood flow in patients with type 2 diabetes mellitus. Clinics (Sao Paulo) 2012; 67:711-7. [PMID: 22892913 PMCID: PMC3400159 DOI: 10.6061/clinics/2012(07)03] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2011] [Accepted: 03/05/2012] [Indexed: 01/12/2023] Open
Abstract
OBJECTIVE To compare the effects of glimepiride and metformin on vascular reactivity, hemostatic factors and glucose and lipid profiles in patients with type 2 diabetes. METHODS A prospective study was performed in 16 uncontrolled patients with diabetes previously treated with dietary intervention. The participants were randomized into metformin or glimepiride therapy groups. After four months, the patients were crossed over with no washout period to the alternative treatment for an additional four-month period on similar dosage schedules. The following variables were assessed before and after four months of each treatment: 1) fasting glycemia, insulin, catecholamines, lipid profiles and HbA1 levels; 2) t-PA and PAI-1 (antigen and activity), platelet aggregation and fibrinogen and plasminogen levels; and 3) the flow indices of the carotid and brachial arteries. In addition, at the end of each period, a 12-hour metabolic profile was obtained after fasting and every 2 hours thereafter. RESULTS Both therapies resulted in similar decreases in fasting glucose, triglyceride and norepinephrine levels, and they increased the fibrinolytic factor plasminogen but decreased t-PA activity. Metformin caused lower insulin and pro-insulin levels and higher glucagon levels and increased systolic carotid diameter and blood flow. Neither metformin nor glimepiride affected endothelial-dependent or endothelial-independent vasodilation of the brachial artery. CONCLUSIONS Glimepiride and metformin were effective in improving glucose and lipid profiles and norepinephrine levels. Metformin afforded more protection against macrovascular diabetes complications, increased systolic carotid artery diameter and total and systolic blood flow, and decreased insulin levels. As both therapies increased plasminogen levels but reduced t-PA activity, a coagulation process was likely still ongoing.
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Affiliation(s)
- Helena Atroch Machado
- Hospital das Clínicas da Faculdade de Medicina da Universidade de São Paulo, Laboratory of Medical Investigation (LIM-18), São Paulo/SP, Brazil
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22
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Campello RS, Alves-Wagner ABT, Abdulkader F, Mori RCT, Machado UF. Carbohydrate- and lipid-enriched meals acutely disrupt glycemic homeostasis by inducing transient insulin resistance in rats. Can J Physiol Pharmacol 2012; 90:537-45. [PMID: 22510071 DOI: 10.1139/y2012-056] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Chronic intake of high-carbohydrate or high-lipid diets is a well-known insulin resistance inducer. This study investigates the immediate effect (1-6 h) of a carbohydrate- or lipid-enriched meal on insulin sensitivity. Fasted rats were refed with standard, carbohydrate-enriched (C), or lipid-enriched (L) meal. Plasma insulin, glucose, and non-esterified fatty acids (NEFA) were measured at 1, 2, 4, and 6 h of refeeding. The glucose-insulin index showed that either carbohydrates or lipids decreased insulin sensitivity at 2 h of refeeding. At this time point, insulin tolerance tests (ITTs) and glucose tolerance tests (GTTs) detected insulin resistance in C rats, while GTT confirmed it in L rats. Reduced glycogen and phosphorylated AKT and GSK3 content revealed hepatic insulin resistance in C rats. Reduced glucose uptake in skeletal muscle subjected to the fatty acid concentration that mimics the high NEFA level of L rats suggests insulin resistance in these animals is mainly in muscle. In conclusion, carbohydrate- or lipid-enriched meals acutely disrupt glycemic homeostasis, inducing a transient insulin resistance, which seems to involve liver and skeletal muscle, respectively. Thus, the insulin resistance observed when those types of diets are chronically consumed may be an evolution of repeated episodes of this transient insulin resistance.
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Affiliation(s)
- Raquel Saldanha Campello
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of Sao Paulo, Brazil.
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23
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Okamoto MM, Anhê GF, Sabino-Silva R, Marques MFDSF, Freitas HS, Mori RCT, Melo KFS, Machado UF. Intensive insulin treatment induces insulin resistance in diabetic rats by impairing glucose metabolism-related mechanisms in muscle and liver. J Endocrinol 2011; 211:55-64. [PMID: 21746792 DOI: 10.1530/joe-11-0105] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Insulin replacement is the only effective therapy to manage hyperglycemia in type 1 diabetes mellitus (T1DM). Nevertheless, intensive insulin therapy has inadvertently led to insulin resistance. This study investigates mechanisms involved in the insulin resistance induced by hyperinsulinization. Wistar rats were rendered diabetic by alloxan injection, and 2 weeks later received saline or different doses of neutral protamine Hagedorn insulin (1.5, 3, 6, and 9 U/day) over 7 days. Insulinopenic-untreated rats and 6U- and 9U-treated rats developed insulin resistance, whereas 3U-treated rats revealed the highest grade of insulin sensitivity, but did not achieve good glycemic control as 6U- and 9U-treated rats did. This insulin sensitivity profile was in agreement with glucose transporter 4 expression and translocation in skeletal muscle, and insulin signaling, phosphoenolpyruvate carboxykinase/glucose-6-phosphatase expression and glycogen storage in the liver. Under the expectation that insulin resistance develops in hyperinsulinized diabetic patients, we believe insulin sensitizer approaches should be considered in treating T1DM.
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Affiliation(s)
- Maristela Mitiko Okamoto
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Avenida Prof. Lineu Prestes, 1524, 05505-900 São Paulo (SP), Brazil.
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24
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Mayer P, Haas B, Celner J, Enzmann H, Pfeifer A. Glitazone-like action of glimepiride and glibenclamide in primary human adipocytes. Diabetes Obes Metab 2011; 13:791-9. [PMID: 21477042 DOI: 10.1111/j.1463-1326.2011.01409.x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
AIM Sulphonylureas (SUs) are among the most widely used oral hypoglycaemic drugs that stimulate insulin secretion. In addition, SUs have pleiotropic effects on other tissues. Conflicting findings have been reported regarding the effects of SUs on adipocytes. We have now investigated the actions of glimepiride and glibenclamide (=glyburide) in primary human adipocytes. METHODS Primary cultured human white pre-adipocytes were differentiated in vitro according to a standard protocol. Lipid accumulation was assessed by Oil Red O staining and determination of triglyceride content; gene expression was measured by RT PCR and Western blotting. RESULTS Initially, we characterized the genes regulated during human pre-adipocyte differentiation by performing global microarray analysis. Treatment with glimepiride and glibenclamide caused an increased accumulation of lipid droplets and triglycerides. In addition, genes involved in lipid metabolism were induced and chemokine expression was decreased. Interestingly, the effects of SUs were generally qualitatively and quantitatively similar to those of pioglitazone. In direct comparison, glibenclamide was more potent than glimepiride with respect to the induction of fatty acid binding protein 4 (FABP4) (EC(50) 0.32 vs. 2.8 µM), an important adipocyte marker gene. SU-induced differentiation was virtually completely blocked by the peroxisome proliferator-activated receptor γ (PPARγ)-antagonist T0070907 but not affected by diazoxide, indicating PPARγ activation by SUs. Repaglinide had no effect on adipogenesis, although it causes insulin liberation like SUs. CONCLUSIONS In primary human pre-adipocytes, glibenclamide and glimepiride strongly induced differentiation, apparently by activating PPARγ. Thus, SUs but not repaglinide may be used to influence insulin resistance beyond their effect on insulin liberation.
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Affiliation(s)
- P Mayer
- Federal Institute for Drugs and Medical Devices, Kurt-Georg-Kiesinger-Allee 3, Bonn, Germany.
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25
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Lee KW, Ku YH, Kim M, Ahn BY, Chung SS, Park KS. Effects of Sulfonylureas on Peroxisome Proliferator-Activated Receptor γ Activity and on Glucose Uptake by Thiazolidinediones. Diabetes Metab J 2011; 35:340-7. [PMID: 21977453 PMCID: PMC3178694 DOI: 10.4093/dmj.2011.35.4.340] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/10/2010] [Accepted: 05/10/2011] [Indexed: 11/15/2022] Open
Abstract
BACKGROUND Sulfonylurea primarily stimulates insulin secretion by binding to its receptor on the pancreatic β-cells. Recent studies have suggested that sulfonylureas induce insulin sensitivity through peroxisome proliferator-activated receptor γ (PPARγ), one of the nuclear receptors. In this study, we investigated the effects of sulfonylurea on PPARγ transcriptional activity and on the glucose uptake via PPARγ. METHODS Transcription reporter assays using Cos7 cells were performed to determine if specific sulfonylureas stimulate PPARγ transactivation. Glimepiride, gliquidone, and glipizide (1 to 500 µM) were used as treatment, and rosiglitazone at 1 and 10 µM was used as a control. The effects of sulfonylurea and rosiglitazone treatments on the transcriptional activity of endogenous PPARγ were observed. In addition, 3T3-L1 adipocytes were treated with rosiglitazone (10 µM), glimepiride (100 µM) or both to verify the effect of glimepiride on rosiglitazone-induced glucose uptake. RESULTS Sulfonylureas, including glimepiride, gliquidone and glipizide, increased PPARγ transcriptional activity, gliquidone being the most potent PPARγ agonist. However, no additive effects were observed in the presence of rosiglitazone. When rosiglitazone was co-treated with glimepiride, PPARγ transcriptional activity and glucose uptake were reduced compared to those after treatment with rosiglitazone alone. This competitive effect of glimepiride was observed only at high concentrations that are not achieved with clinical doses. CONCLUSION Sulfonylureas like glimepiride, gliquidone and glipizide increased the transcriptional activity of PPARγ. Also, glimepiride was able to reduce the effect of rosiglitazone on PPARγ agonistic activity and glucose uptake. However, the competitive effect does not seem to occur at clinically feasible concentrations.
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Affiliation(s)
- Kyeong Won Lee
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Yun Hyi Ku
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Min Kim
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Byung Yong Ahn
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Sung Soo Chung
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
| | - Kyong Soo Park
- Department of Internal Medicine, Seoul National University College of Medicine, Seoul, Korea
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26
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de Leon EB, Bortoluzzi A, Rucatti A, Nunes RB, Saur L, Rodrigues M, Oliveira U, Alves-Wagner AB, Xavier LL, Machado UF, Schaan BD, Dall'Ago P. Neuromuscular electrical stimulation improves GLUT-4 and morphological characteristics of skeletal muscle in rats with heart failure. Acta Physiol (Oxf) 2011; 201:265-73. [PMID: 20698833 DOI: 10.1111/j.1748-1716.2010.02176.x] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM Changes in skeletal muscle morphology and metabolism are associated with limited functional capacity in heart failure, which can be attenuated by neuromuscular electrical stimulation (ES). The purpose of the present study was to analyse the effects of ES upon GLUT-4 protein content, fibre structure and vessel density of the skeletal muscle in a rat model of HF subsequent to myocardial infarction. METHODS Forty-four male Wistar rats were assigned to one of four groups: sham (S), sham submitted to ES (S+ES), heart failure (HF) and heart failure submitted to ES (HF+ES). The rats in the ES groups were submitted to ES of the left leg during 20 days (2.5 kHz, once a day, 30 min, duty cycle 50%- 15 s contraction/15 s rest). After this period, the left tibialis anterior muscle was collected from all the rats for analysis. RESULTS HF+ES rats showed lower values of lung congestion when compared with HF rats (P = 0.0001). Although muscle weight was lower in HF rats than in the S group, thus indicating hypotrophy, 20 days of ES led to their recovery (P < 0.0001). In both groups submitted to ES, there was an increase in muscle vessel density (P < 0.04). Additionally, heart failure determined a 49% reduction in GLUT-4 protein content (P < 0.03), which was recovered by ES (P < 0.01). CONCLUSION In heart failure, ES improves morphological changes and raises GLUT-4 content in skeletal muscle.
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Affiliation(s)
- E B de Leon
- Laboratório de Fisiologia, UFCSPA, Rio Grande do Sul, Brazil
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Yokoyama H, Sone H, Yamada D, Honjo J, Haneda M. Contribution of glimepiride to basal-prandial insulin therapy in patients with type 2 diabetes. Diabetes Res Clin Pract 2011; 91:148-53. [PMID: 21067837 DOI: 10.1016/j.diabres.2010.10.007] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/05/2010] [Revised: 09/21/2010] [Accepted: 10/04/2010] [Indexed: 11/29/2022]
Abstract
AIM To investigate the efficacy of continuing glimepiride in combination with basal-prandial insulin therapy in type 2 diabetes. METHODS An open crossover study was performed with arms of discontinuation and continuation of glimepiride in 25 subjects with mean diabetes duration of 17 years and 5 years of insulin treatment combined with glimepiride plus metformin. At entry and at the end of each 3-month arm, meal tolerance tests were performed for measurements of blood glucose and C-peptide. RESULTS In terms of between-treatment differences (discontinuation vs. continuation arm of glimepiride) during meal tolerance tests performed at the ends of arms, significant increases in plasma glucose were seen on the discontinuation arm at 0-, 30-, and 60-min, while significant decreases in serum C-peptide were observed at 60- and 120-min. A1C values of the discontinuation arm significantly increased (from 6.6 ± 0.6 at baseline to 7.7 ± 0.8 at 3-months, p<0.0001). Increases in A1C were closely correlated with decreases in area under the curve of meal-stimulated serum C-peptide (r=-0.61, p<0.0001). CONCLUSIONS Since endogenous insulin secretion is more physiological than subcutaneous insulin injection, continuing glimepiride may remain beneficial, partly through enhancing insulin secretion, in individuals with a long duration of diabetes and basal-prandial insulin therapy.
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Affiliation(s)
- Hiroki Yokoyama
- Jiyugaoka Medical Clinic, Internal Medicine, Obihiro, Japan.
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Poletto AC, Anhê GF, Eichler P, Takahashi HK, Furuya DT, Okamoto MM, Curi R, Machado UF. Soybean and sunflower oil-induced insulin resistance correlates with impaired GLUT4 protein expression and translocation specifically in white adipose tissue. Cell Biochem Funct 2010; 28:114-21. [PMID: 20087847 DOI: 10.1002/cbf.1628] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
Abstract
Free fatty acids are known for playing a crucial role in the development of insulin resistance. High fat intake is known for impairing insulin sensitivity; however, the effect of vegetable-oil injections have never been investigated. The present study investigated the effects of daily subcutaneous injections (100 microL) of soybean (SB) and sunflower (SF) oils, during 7 days. Both treated groups developed insulin resistance as assessed by insulin tolerance test. The mechanism underlying the SB- and SF-induced insulin resistance was shown to involve GLUT4. In SB- and SF-treated animals, the GLUT4 protein expression was reduced approximately 20% and 10 min after an acute in vivo stimulus with insulin, the plasma membrane GLUT4 content was approximately 60% lower in white adipose tissue (WAT). No effects were observed in skeletal muscle. Additionally, both oil treatments increased mainly the content of palmitic acid ( approximately 150%) in WAT, which can contribute to explain the GLUT4 regulations. Altogether, the present study collects evidence that those oil treatments might generate insulin resistance by targeting GLUT4 expression and translocation specifically in WAT. These alterations are likely to be caused due to the specific local increase in saturated fatty acids that occurred as a consequence of oil daily injections.
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Affiliation(s)
- Ana Cláudia Poletto
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, Brazil
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de Castro Barbosa T, de Carvalho JEN, Poyares LL, Bordin S, Machado UF, Nunes MT. Potential role of growth hormone in impairment of insulin signaling in skeletal muscle, adipose tissue, and liver of rats chronically treated with arginine. Endocrinology 2009; 150:2080-6. [PMID: 19106217 DOI: 10.1210/en.2008-1487] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
We have shown that rats chronically treated with Arginine (Arg), although normoglycemic, exhibit hyperinsulinemia and decreased blood glucose disappearance rate after an insulin challenge. Attempting to investigate the processes underlying these alterations, male Wistar rats were treated with Arg (35 mg/d), in drinking water, for 4 wk. Rats were then acutely stimulated with insulin, and the soleus and extensorum digitalis longus muscles, white adipose tissue (WAT), and liver were excised for total and/or phosphorylated insulin receptor (IR), IR substrate 1/2, Akt, Janus kinase 2, signal transducer and activator of transcription (STAT) 1/3/5, and p85alpha/55alpha determination. Muscles and WAT were also used for plasma membrane (PM) and microsome evaluation of glucose transporter (GLUT) 4 content. Pituitary GH mRNA, GH, and liver IGF-I mRNA expression were estimated. It was shown that Arg treatment: 1) did not affect phosphotyrosine-IR, whereas it decreased phosphotyrosine-IR substrate 1/2 and phosphoserine-Akt content in all tissues studied, indicating that insulin signaling is impaired at post-receptor level; 2) decreased PM GLUT4 content in both muscles and WAT; 3) increased the pituitary GH mRNA, GH, and liver IGF-I mRNA expression, the levels of phosphotyrosine-STAT5 in both muscles, phosphotyrosine-Janus kinase 2 in extensorum digitalis longus, phosphotyrosine-STAT3 in liver, and WAT as well as total p85alpha in soleus, indicating that GH signaling is enhanced in these tissues; and 4) increased p55alpha total content in muscles, WAT, and liver. The present findings provide the molecular mechanisms by which insulin resistance and, by extension, reduced GLUT4 content in PM of muscles and WAT take place after chronic administration of Arg, and further suggest a putative role for GH in its genesis, considering its diabetogenic effect.
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Affiliation(s)
- Thais de Castro Barbosa
- Department of Physiology and Biophysics, Institute of Biomedical Sciences, University of São Paulo, 05508-900 São Paulo, São Paulo, Brazil
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