Angiotensin II Type 1 Receptor Antagonism Mediates Uncoupling Protein 2-Driven Oxidative Stress and Ameliorates Pancreatic Islet β-Cell Function in Young Type 2 Diabetic Mice

2007 ◽  
Vol 9 (7) ◽  
pp. 869-878 ◽  
Author(s):  
Kwan Yi Chu ◽  
Po Sing Leung
2011 ◽  
Vol 106 (3) ◽  
pp. 383-389 ◽  
Author(s):  
Pál Brasnyó ◽  
Gergő A. Molnár ◽  
Márton Mohás ◽  
Lajos Markó ◽  
Boglárka Laczy ◽  
...  

Although resveratrol has widely been studied for its potential health benefits, little is known about its metabolic effects in humans. Our aims were to determine whether the polyphenol resveratrol improves insulin sensitivity in type 2 diabetic patients and to gain some insight into the mechanism of its action. After an initial general examination (including blood chemistry), nineteen patients enrolled in the 4-week-long double-blind study were randomly assigned into two groups: a resveratrol group receiving oral 2 × 5 mg resveratrol and a control group receiving placebo. Before and after the second and fourth weeks of the trial, insulin resistance/sensitivity, creatinine-normalised ortho-tyrosine level in urine samples (as a measure of oxidative stress), incretin levels and phosphorylated protein kinase B (pAkt):protein kinase B (Akt) ratio in platelets were assessed and statistically analysed. After the fourth week, resveratrol significantly decreased insulin resistance (homeostasis model of assessment for insulin resistance) and urinary ortho-tyrosine excretion, while it increased the pAkt:Akt ratio in platelets. On the other hand, it had no effect on parameters that relate to β-cell function (i.e. homeostasis model of assessment of β-cell function). The present study shows for the first time that resveratrol improves insulin sensitivity in humans, which might be due to a resveratrol-induced decrease in oxidative stress that leads to a more efficient insulin signalling via the Akt pathway.


2021 ◽  
Vol 12 ◽  
Author(s):  
Ker Woon Choy ◽  
Zuhaida Md Zain ◽  
Dharmani Devi Murugan ◽  
Nelli Giribabu ◽  
Nor Hisam Zamakshshari ◽  
...  

Type 2 diabetes mellitus is characterized by both resistance to the action of insulin and defects in insulin secretion. Bird’s nest, which is derived from the saliva of swiftlets are well known to possess multiple health benefits dating back to Imperial China. However, it’s effect on diabetes mellitus and influence on the actions of insulin action remains to be investigated. In the present study, the effect of standardized aqueous extract of hydrolyzed edible bird nest (HBN) on metabolic characteristics and insulin signaling pathway in pancreas, liver and skeletal muscle of db/db, a type 2 diabetic mice model was investigated. Male db/db diabetic and its euglycemic control, C57BL/6J mice were administered HBN (75 and 150 mg/kg) or glibenclamide (1 mg/kg) orally for 28 days. Metabolic parameters were evaluated by measuring fasting blood glucose, serum insulin and oral glucose tolerance test (OGTT). Insulin signaling and activation of inflammatory pathways in liver, adipose, pancreas and muscle tissue were evaluated by Western blotting and immunohistochemistry. Pro-inflammatory cytokines were measured in the serum at the end of the treatment. The results showed that db/db mice treated with HBN significantly reversed the elevated fasting blood glucose, serum insulin, serum pro-inflammatory cytokines levels and the impaired OGTT without affecting the body weight of the mice in all groups. Furthermore, HBN treatment significantly ameliorated pathological changes and increased the protein expression of insulin, and glucose transporters in the pancreatic islets (GLUT-2), liver and skeletal muscle (GLUT-4). Likewise, the Western blots analysis denotes improved insulin signaling and antioxidant enzyme, decreased reactive oxygen species producing enzymes and inflammatory molecules in the liver and adipose tissues of HBN treated diabetic mice. These results suggest that HBN improves β-cell function and insulin signaling by attenuation of oxidative stress mediated chronic inflammation in the type 2 diabetic mice.


Cells ◽  
2021 ◽  
Vol 10 (12) ◽  
pp. 3328
Author(s):  
Eloisa Aparecida Vilas-Boas ◽  
Davidson Correa Almeida ◽  
Leticia Prates Roma ◽  
Fernanda Ortis ◽  
Angelo Rafael Carpinelli

A high caloric intake, rich in saturated fats, greatly contributes to the development of obesity, which is the leading risk factor for type 2 diabetes (T2D). A persistent caloric surplus increases plasma levels of fatty acids (FAs), especially saturated ones, which were shown to negatively impact pancreatic β-cell function and survival in a process called lipotoxicity. Lipotoxicity in β-cells activates different stress pathways, culminating in β-cells dysfunction and death. Among all stresses, endoplasmic reticulum (ER) stress and oxidative stress have been shown to be strongly correlated. One main source of oxidative stress in pancreatic β-cells appears to be the reactive oxygen species producer NADPH oxidase (NOX) enzyme, which has a role in the glucose-stimulated insulin secretion and in the β-cell demise during both T1 and T2D. In this review, we focus on the acute and chronic effects of FAs and the lipotoxicity-induced β-cell failure during T2D development, with special emphasis on the oxidative stress induced by NOX, the ER stress, and the crosstalk between NOX and ER stress.


2002 ◽  
Vol 57 (1) ◽  
pp. 1-10 ◽  
Author(s):  
Shin-ichi Gorogawa ◽  
Yoshitaka Kajimoto ◽  
Yutaka Umayahara ◽  
Hideaki Kaneto ◽  
Hirotaka Watada ◽  
...  

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
Min Shen ◽  
Dongdong Sun ◽  
Weijie Li ◽  
Bing Liu ◽  
Shenxu Wang ◽  
...  

Aim. To investigate the combination effects and mechanisms of valsartan (angiotensin II type 1 receptor blocker) and LAF237 (DPP-IV inhibitor) on prevention against oxidative stress and inflammation injury in db/db mice aorta.Methods. Db/db mice (n=40) were randomized to receive valsartan, LAF237, valsartan plus LAF237, or saline. Oxidative stress and inflammatory reaction in diabetic mice aorta were examined.Results. Valsartan or LAF237 pretreatment significantly increased plasma GLP-1 expression, reduced apoptosis of endothelial cells isolated from diabetic mice aorta. The expression of NAD(P)H oxidase subunits also significantly decreased resulting in decreased superoxide production and ICAM-1 (fold change: valsartan : 7.5 ± 0.7,P<0.05; LAF237: 10.2 ± 1.7,P<0.05), VCAM-1 (fold change: valsartan : 5.2 ± 1.2,P<0.05; LAF237: 4.8 ± 0.6,P<0.05), and MCP-1 (fold change: valsartan: 3.2 ± 0.6, LAF237: 4.7 ± 0.8;P<0.05) expression. Moreover, the combination treatment with valsartan and LAF237 resulted in a more significant increase of GLP-1 expression. The decrease of the vascular oxidative stress and inflammation reaction was also higher than monotherapy with valsartan or LAF237.Conclusion. These data indicated that combination treatment with LAF237 and valsartan acts in a synergistic manner on vascular oxidative stress and inflammation in type 2 diabetic mice.


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