Protective effects of either C‐peptide or l ‐arginine on pancreatic β‐cell function, proliferation, and oxidative stress in streptozotocin‐induced diabetic rats

2018 ◽  
Vol 234 (7) ◽  
pp. 11500-11510 ◽  
Author(s):  
Merhan Mamdouh Ragy ◽  
Sabreen Mahmoud Ahmed
2014 ◽  
Vol 306 (10) ◽  
pp. E1163-E1175 ◽  
Author(s):  
Hisashi Yokomizo ◽  
Toyoshi Inoguchi ◽  
Noriyuki Sonoda ◽  
Yuka Sakaki ◽  
Yasutaka Maeda ◽  
...  

Intrauterine environment may influence the health of postnatal offspring. There have been many studies on the effects of maternal high-fat diet (HFD) on diabetes and glucose metabolism in offspring. Here, we investigated the effects in male and female offspring. C57/BL6J mice were bred and fed either control diet (CD) or HFD from conception to weaning, and offspring were fed CD or HFD from 6 to 20 wk. At 20 wk, maternal HFD induced glucose intolerance and insulin resistance in offspring. Additionally, liver triacylglycerol content, adipose tissue mass, and inflammation increased in maternal HFD. In contrast, extending previous observations, insulin secretion at glucose tolerance test, islet area, insulin content, and PDX-1 mRNA levels in isolated islets were lower in maternal HFD in males, whereas they were higher in females. Oxidative stress in islets increased in maternal HFD in males, whereas there were no differences in females. Plasma estradiol levels were lower in males than in females and decreased in offspring fed HFD and also decreased by maternal HFD, suggesting that females may be protected from insulin deficiency by inhibiting oxidative stress. In conclusion, maternal HFD induced insulin resistance and deterioration of pancreatic β-cell function, with marked sex differences in adult offspring accompanied by adipose tissue inflammation and liver steatosis. Additionally, our results demonstrate that potential mechanisms underlying sex differences in pancreatic β-cell function may be related partially to increases in oxidative stress in male islets and decreased plasma estradiol levels in males.


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

1998 ◽  
Vol 30 (7) ◽  
pp. 2913 ◽  
Author(s):  
M Yamaguchi ◽  
M Kuzume ◽  
T Matsumoto ◽  
H Shimura ◽  
H Nakano ◽  
...  

Metabolism ◽  
1985 ◽  
Vol 34 (8) ◽  
pp. 695-701 ◽  
Author(s):  
G. Marchesini ◽  
A. Melli ◽  
G.A. Checchia ◽  
Loretta Mattioli ◽  
M. Capelli ◽  
...  

2019 ◽  
Author(s):  
Xin Tong ◽  
Zunaira Chaudry ◽  
Chih-Chun Lee ◽  
Robert N. Bone ◽  
Sukrati Kanojia ◽  
...  

ABSTRACTObjectivesEpidemiological studies indicate that first- and second-hand cigarette smoke (CS) exposure are important risk factors for the development of type 2 diabetes (T2D). Additionally, elevated diabetes risk has been reported to occur within a short period of time after smoking cessation, and health risks associated with smoking are increased when combined with obesity. At present, the mechanisms underlying these associations remain incompletely understood. The objective of this study was to test the impact of CS exposure on pancreatic β-cell function using rodent and in vitro models.MethodsBeginning at 8 weeks of age, C57BL/6J mice were concurrently fed high fat-diet (HFD) and exposed to CS for 11 weeks, followed by an additional 11 weeks of smoking cessation with continued HFD exposure. Glucose tolerance testing was performed during CS exposure and during the cessation period. Cultured β-cells (INS-1) and primary islets were exposed ex vivo to CS extract (CSE), and β-cell function and viability were tested. Since CS increases ceramide in lungs cells and these bioactive sphingolipids have been implicated in pancreatic β-cell dysfunction in diabetes, islet and β-cell sphingolipid levels were measured in islets from CS-exposed mice and in CSE-treated islets and INS-1 cells using liquid chromatography-tandem mass spectrometry.ResultsCompared to HFD-fed ambient air-exposed mice, HFD-fed and CS- exposed mice had reduced weight gain and better glucose tolerance during the active smoking period. Following smoking cessation, CS-mice exhibited rapid weight gain and a significantly greater increase in glucose intolerance compared to non-smoking control mice. CS-exposed mice had higher serum proinsulin/insulin ratios, indicative of β-cell dysfunction, significantly lower β-cell mass (p=0.02), and reduced β-cell proliferation (p=0.006), and increased islet ceramide accumulation. Ex vivo exposure of isolated islets to CSE was sufficient to increase islet ceramide accumulation, reduce insulin gene expression and glucose-stimulated insulin secretion, and increase β-cell oxidative and ER stress. Treatment with the antioxidant N-acetylcysteine, markedly attenuated the effects of CSE on ceramide levels, restored β-cell function and survival, and increased cyclin D2 expression, while also reducing activation of β-cell ER and oxidative stress.ConclusionsOur results indicate that CS exposure inhibits insulin production, processing, and secretion and reduced β-cell viability and proliferation. These effects were linked to increased β-cell oxidative and ER stress and ceramide accumulation. Mice fed HFD continued to experience detrimental effects of CS exposure even during smoking cessation. Elucidation of mechanisms by which CS exposure impairs β-cell function in synergy with obesity will help design therapeutic and preventive interventions for both active and former smokers.


2007 ◽  
Vol 103 (5) ◽  
pp. 1764-1771 ◽  
Author(s):  
Sunmin Park ◽  
Sang Mee Hong ◽  
Ji Eun Lee ◽  
So Ra Sung

In this study, we investigated the effects of a high-fat diet and exercise on pancreatic β-cell function and mass and its molecular mechanism in 90% pancreatectomized male rats. The pancreatectomized diabetic rats were given control diets (20% energy) or a high-fat (HF) diet (45% energy) for 12 wk. Half of each group was given regular exercise on an uphill treadmill at 20 m/min for 30 min 5 days/wk. HF diet lowered first-phase insulin secretion with glucose loading, whereas exercise training reversed this decrease. However, second-phase insulin secretion did not differ among the groups. Exercise increased pancreatic β-cell mass. This resulted from stimulated β-cell proliferation and reduced apoptosis, which is associated with potentiated insulin or IGF-I signaling through insulin receptor substrate-2 (IRS2) induction. Although the HF diet resulted in decreased proliferation and accelerated apoptosis by weakened insulin and IGF-I signaling from reduction of IRS2 protein, β-cell mass was maintained in HF rats just as much as in control rats via increased individual β-cell size and neogenesis from precursor cells. Consistent with the results of β-cell proliferation, pancreas duodenal homeobox-1 expression increased in the islets of rats in the exercise groups, and it was reduced the most in rats fed the HF diet. In conclusion, exercise combined with a moderate fat diet is a good way to maximize β-cell function and mass through IRS2 induction to alleviate the diabetic condition. This study suggests that dietary fat contents and exercise modulate β-cell function and mass to overcome insulin resistance in two different pathways.


2021 ◽  
Vol 22 (4) ◽  
pp. 1509
Author(s):  
Natsuki Eguchi ◽  
Nosratola D. Vaziri ◽  
Donald C. Dafoe ◽  
Hirohito Ichii

Diabetes is a chronic metabolic disorder characterized by inappropriately elevated glucose levels as a result of impaired pancreatic β cell function and insulin resistance. Extensive studies have been conducted to elucidate the mechanism involved in the development of β cell failure and death under diabetic conditions such as hyperglycemia, hyperlipidemia, and inflammation. Of the plethora of proposed mechanisms, endoplasmic reticulum (ER) stress, mitochondrial dysfunction, and oxidative stress have been shown to play a central role in promoting β cell dysfunction. It has become more evident in recent years that these 3 factors are closely interrelated and importantly aggravate each other. Oxidative stress in particular is of great interest to β cell health and survival as it has been shown that β cells exhibit lower antioxidative capacity. Therefore, this review will focus on discussing factors that contribute to the development of oxidative stress in pancreatic β cells and explore the downstream effects of oxidative stress on β cell function and health. Furthermore, antioxidative capacity of β cells to counteract these effects will be discussed along with new approaches focused on preserving β cells under oxidative conditions.


2001 ◽  
Vol 276 (33) ◽  
pp. 31099-31104 ◽  
Author(s):  
Hideaki Kaneto ◽  
Gang Xu ◽  
Ki-Ho Song ◽  
Kiyoshi Suzuma ◽  
Susan Bonner-Weir ◽  
...  

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