Circulating adiponectin concentrations are increased by dietary resistant starch and correlate with serum 25-hydroxycholecalciferol concentrations and kidney function in Zucker diabetic fatty rats

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• 作者：Gar Yee Koh^a ; ^b ; Rachel Derscheid^c ; Kelly N.Z. Fuller^a ; ^d ; Rudy J. Valentine^d ; Shu En Leow^b ; Leah Reed^b ; Emily Wisecup^b ; Kevin L. Schalinske^a ; ^b ; Matthew J. Rowling^a ; ^b ; ^{mrowling@iastate.edu" class="auth_mail" title="E-mail the corresponding author}
• 关键词：Vitamin D ; Adiponectin ; Renin-angiotensin system ; Resistant starch ; Type 2 diabetes ; Zucker diabetic fatty rat
• 刊名：Nutrition Research
• 出版年：2016
• 出版时间：April 2016
• 年：2016
• 卷：36
• 期：4
• 页码：311-319
• 全文大小：599 K

文摘

We previously reported that dietary resistant starch (RS) type 2 prevented proteinuria and promoted vitamin D balance in type 2 diabetic (T2D) rats. Here, our primary objective was to identify potential mechanisms that could explain our earlier observations. We hypothesized that RS could promote adiponectin secretion and regulate the renin-angiotensin system activity in the kidney. Lean Zucker rats (n = 5) were fed control diet; Zucker diabetic fatty rats (n = 5/group) were fed either an AIN-93G control diet (DC) or AIN-93G diet containing either 10% RS or 20% RS (HRS) for 6 weeks. Resistant starch had no impact on blood glucose concentrations and hemoglobin A1c percentage, yet circulating adiponectin was 77% higher in HRS-fed rats, compared to DC rats. Adiponectin concentrations strongly correlated with serum 25-hydroxycholecalciferol (r = 0.815; P < .001) and urinary creatinine concentrations (r = 0.818; P < .001) and inversely correlated with proteinuria (r = −0.583; P = .02). Serum angiotensin II concentrations were 44% lower, and expression of the angiotensin II receptor, type 1, was attenuated in RS-fed rats. Moreover, we observed a 14-fold increase in messenger RNA expression of nephrin, which is required for functioning of the renal filtration barrier, in HRS rats. The HRS, but not 10% RS diet, increased circulating 25-hydroxycholecalciferol concentrations and attenuated urinary loss of vitamin D metabolites in Zucker diabetic fatty rats. Taken together, we provide evidence that vitamin D balance in the presence of hyperglycemia is strongly associated with serum adiponectin levels and reduced renal renin-angiotensin system signaling.