Thiazolidinediones improve β-cell function in type 2 diabetic patients

2007 ◽  
Vol 292 (3) ◽  
pp. E871-E883 ◽  
Author(s):  
Amalia Gastaldelli ◽  
Ele Ferrannini ◽  
Yoshinori Miyazaki ◽  
Masafumi Matsuda ◽  
Andrea Mari ◽  
...  

Thiazolidinediones (TZDs) improve glycemic control and insulin sensitivity in patients with type 2 diabetes mellitus (T2DM). There is growing evidence from in vivo and in vitro studies that TZDs improve pancreatic β-cell function. The aim of this study was to determine whether TZD-induced improvement in glycemic control is associated with improved β-cell function. We studied 11 normal glucose-tolerant and 53 T2DM subjects [age 53 ± 2 yr; BMI 29.4 ± 0.8 kg/m2; fasting plasma glucose (FPG) 10.3 ± 0.4 mM; Hb A1c 8.2 ± 0.3%]. Diabetic patients were randomized to receive placebo or TZD for 4 mo. Subjects received 1) 2-h OGTT with determination of plasma glucose, insulin, and C-peptide concentrations and 2) two-step euglycemic insulin (40 and 160 mUm−2min−1) clamp with [3-3H]glucose. T2DM patients were then randomized to receive 4 mo of treatment with pioglitazone (45 mg/day), rosiglitazone (8 mg/day), or placebo. Pioglitazone and rosiglitazone similarly improved FPG, mean plasma glucose during OGTT, Hb A1c, and insulin-mediated total body glucose disposal (Rd) and decreased mean plasma FFA during OGTT (all P < 0.01, ANOVA). The insulin secretion/insulin resistance (disposition) index [ΔISR(AUC)/Δglucose(AUC) ÷ IR] was significantly improved in all TZD-treated groups: +1.8 ± 0.7 (PIO + drug-naïve diabetics), +0.7 ± 0.3 (PIO + sulfonylurea-treated diabetics), and 0.7 ± 0.2 (ROSI + sulfonylurea-withdrawn diabetics) vs. −0.2 ± 0.3 in the two placebo groups ( P < 0.01, all TZDs vs. placebo, ANOVA). Improved insulin secretion correlated positively with increased body weight, fat mass, and Rd and inversely with decreased plasma glucose and FFA during the OGTT. In T2DM patients, TZD treatment leads to improved β-cell function, which correlates strongly with improved glycemic control.

Cureus ◽  
2021 ◽  
Author(s):  
Edavan Pulikkanath Praveen ◽  
Sunil Chouhan ◽  
Jayaprakash Sahoo ◽  
Rajesh Khadgawat ◽  
Madan Lal Khurana ◽  
...  

2018 ◽  
Vol 46 (1) ◽  
pp. 335-350 ◽  
Author(s):  
Yuting Ruan ◽  
Nie Lin ◽  
Qiang Ma ◽  
Rongping Chen ◽  
Zhen Zhang ◽  
...  

Background/Aims: The islet is an important endocrine organ to secrete insulin to regulate the metabolism of glucose and maintain the stability of blood glucose. Long noncoding RNAs (lncRNAs) are involved in a variety of biological functions and play key roles in many diseases, including type 2 diabetes (T2D). The aim of this study was to determine whether lncRNA-p3134 is associated with glucose metabolism and insulin signaling in pancreatic β cells. Methods: LncRNA microarray technology was used to identify the differentially expressed circulating lncRNAs in T2D patients. RT-PCR analyses were performed to determine the expression of lncRNA-p3134 in 30 pairs of diabetic and non-diabetic patients. The correlation of lncRNA-p3134 to clinical data from T2D patients was analyzed. LncRNA-p3134 was overexpressed in Min6 cells and db/db mice by adenovirus-mediated technology. CCK-8, TUNEL, Western blot, glucose-stimulated insulin secretion (GSIS), ELISAs and immunochemistry were performed to determine the effect of lncRNA-p3134 on proliferation, apoptosis and insulin secretion both in vitro and vivo. Results: The circulating level of lncRNA-p3134 was higher in diabetic patients than in non-diabetic controls and was correlated with fasting blood glucose and HOMA-β levels. The lncRNA-p3134 had risen by 4 times in serum exosomes but nearly unchanged in exosome-free samples. The secretion of lncRNA-p3134 was dynamically modulated by glucose in both Min6 cells and isolated mouse islet cells. LncRNA-p3134 positively regulate GSIS through promoting of key regulators (Pdx-1, MafA, GLUT2 and Tcf7l2) in β cells. In addition, the overexpression of lncRNA-p3134 resulted in a decreased apoptosis ratio and partially reversed the glucotoxicity effects on GSIS function in Min6 cells. The restoration of insulin synthesis and secretion the increase of the insulin positive cells areas by upregulation of lncRNA-p3134 in db/db mice confirmed the compensatory role of lncRNA-p3134 to preserve β-cell function. Furthermore, a protective effect of lncRNA-p3134 on GSIS by positive modulation of PI3K/Akt/mTOR signaling was also confirmed. After blocking the PI3K/AKT signals with their specific inhibitor, the effect of overexpressed lncRNA-p3134 on insulin secretion was obviously attenuated. Conclusion: Taken together, the results of this study provide new insights into lncRNA-p3134 regulation in pancreatic β cells and provide a better understanding of novel mechanism of glucose homeostasis.


Gene ◽  
2018 ◽  
Vol 652 ◽  
pp. 1-6 ◽  
Author(s):  
Edith Elena Uresti-Rivera ◽  
Rocío Edith García-Jacobo ◽  
José Alfredo Méndez-Cabañas ◽  
Laura Elizabeth Gaytan-Medina ◽  
Nancy Cortez-Espinosa ◽  
...  

Author(s):  
Hayat Aljaibeji ◽  
Noha Mousaad Elemam ◽  
Abdul Khader Mohammed ◽  
Hind Hasswan ◽  
Mahammad Al Thahyabat ◽  
...  

Abstract Let7b-5p is a member of the Let-7 miRNA family and one of the top expressed miRNAs in human islets that implicated in glucose homeostasis. The levels of Let7b-5p in type 2 diabetes (T2DM) patients or its role in β-cell function is still unclear. In the current study, we measured the serum levels of let7b-5p in Emirati patients with T2DM (with/without complications) and control subjects. Overexpression or silencing of let7b-5p in INS-1 (832/13) cells was performed to investigate the impact on insulin secretion, content, cell viability, apoptosis, and key functional genes. We found that serum levels of let7b-5p are significantly (p<0.05) higher in T2DM-patients or T2DM with complications compared to control subjects. Overexpression of let7b-5p increased insulin content and decreased glucose-stimulated insulin secretion, whereas silencing of let7b-5p reduced insulin content and secretion. Modulation of the expression levels of let7b-5p did not influence cell viability nor apoptosis. Analysis of mRNA and protein expression of hallmark genes in let7b-5p transfected cells revealed a marked dysregulation of Insulin, Pancreatic And Duodenal Homeobox 1 (PDX1), glucokinase (GCK), glucose transporter 2 (GLUT2), and INSR. In conclusion, an appropriate level of let7b-5p is essential to maintain β-cell function and may be regarded as a biomarker for T2DM.


1999 ◽  
Vol 277 (2) ◽  
pp. E283-E290 ◽  
Author(s):  
Pankaj Shah ◽  
Ananda Basu ◽  
Rita Basu ◽  
Robert Rizza

People with type 2 diabetes have defects in both α- and β-cell function. To determine whether lack of suppression of glucagon causes hyperglycemia when insulin secretion is impaired but not when insulin secretion is intact, twenty nondiabetic subjects were studied on two occasions. On both occasions, a “prandial” glucose infusion was given over 5 h while endogenous hormone secretion was inhibited. Insulin was infused so as to mimic either a nondiabetic ( n = 10) or diabetic ( n = 10) postprandial profile. Glucagon was infused at a rate of 1.25 ng ⋅ kg−1 ⋅ min−1, beginning either at time zero to prevent a fall in glucagon (nonsuppressed study day) or at 2 h to create a transient fall in glucagon (suppressed study day). During the “diabetic” insulin profile, lack of glucagon suppression resulted in a marked increase ( P < 0.002) in both the peak glucose concentration (11.9 ± 0.4 vs. 8.9 ± 0.4 mmol/l) and the area above basal of glucose (927 ± 77 vs. 546 ± 112 mmol ⋅ l−1 ⋅ 6 h) because of impaired ( P < 0.001) suppression of glucose production. In contrast, during the “nondiabetic” insulin profile, lack of suppression of glucagon resulted in only a slight increase ( P< 0.02) in the peak glucose concentration (9.1 ± 0.4 vs. 8.4 ± 0.3 mmol/l) and the area above basal of glucose (654 ± 146 vs. 488 ± 118 mmol ⋅ l−1 ⋅ 6 h). Of interest, when glucagon was suppressed, glucose concentrations differed only minimally during the nondiabetic and diabetic insulin profiles. These data indicate that lack of suppression of glucagon can cause substantial hyperglycemia when insulin availability is limited, therefore implying that inhibitors of glucagon secretion and/or glucagon action are likely to be useful therapeutic agents in such individuals.


Healthcare ◽  
2021 ◽  
Vol 9 (8) ◽  
pp. 1010
Author(s):  
Wei-Hao Hsu ◽  
Chin-Wei Tseng ◽  
Yu-Ting Huang ◽  
Ching-Chao Liang ◽  
Mei-Yueh Lee ◽  
...  

Prediabetes should be viewed as an increased risk for diabetes and cardiovascular disease. In this study, we investigated its prevalence among the relatives and spouses of patients with type 2 diabetes or risk factors for prediabetes, insulin resistance, and β-cell function. A total of 175 individuals were included and stratified into three groups: controls, and relatives and spouses of type 2 diabetic patients. We compared clinical characteristics consisting of a homeostatic model assessment for insulin resistance (HOMA-IR) and beta cell function (HOMA-β), a quantitative insulin sensitivity check index (QUICKI), and triglyceride glucose (TyG) index. After a multivariable linear regression analysis, the relative group was independently correlated with high fasting glucose, a high TyG index, and low β-cell function; the relatives and spouses were independently associated with a low QUICKI. The relatives and spouses equally had a higher prevalence of prediabetes. These study also indicated that the relatives had multiple factors predicting the development of diabetes mellitus, and that the spouses may share a number of common environmental factors associated with low insulin sensitivity.


Endocrinology ◽  
2015 ◽  
Vol 157 (2) ◽  
pp. 624-635 ◽  
Author(s):  
Joon Ha ◽  
Leslie S. Satin ◽  
Arthur S. Sherman

Abstract Type 2 diabetes (T2D) is generally thought to result from the combination of 2 metabolic defects, insulin resistance, which increases the level of insulin required to maintain glucose within the normal range, and failure of insulin-secreting pancreatic β-cells to compensate for the increased demand. We build on a mathematical model pioneered by Topp and colleagues to elucidate how compensation succeeds or fails. Their model added a layer of slow negative feedback to the classic insulin-glucose loop in the form of a slow, glucose-dependent birth and death law governing β-cell mass. We add to that model regulation of 2 aspects of β-cell function on intermediate time scales. The model quantifies the relative contributions of insulin action and insulin secretion defects to T2D and explains why prevention is easier than cure. The latter is a consequence of a threshold separating the normoglycemic and diabetic states (bistability), which also underlies the success of bariatric surgery and acute caloric restriction in rapidly reversing T2D. The threshold concept gives new insight into “Starling's Law of the Pancreas,” whereby insulin secretion is higher for prediabetics and early diabetics than for normal individuals.


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