title: Circulating adiponectin concentrations are increased by dietary resistant starch and correlate with serum 25-hydroxycholecalciferol concentrations and kidney function in Zucker diabetic fatty rats.
abstract: 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.
authors.affiliation: The Interdepartmental Graduate Program in Nutritional Sciences, Iowa State University, Ames, IA, USA; Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA.
authors.forename: Gar Yee
authors.initials: GY
authors.lastname: Koh
authors.affiliation: Veterinary Diagnostic Laboratory, College of Veterinary Medicine, Iowa State University, Ames, IA, USA.
authors.forename: Rachel
authors.initials: R
authors.lastname: Derscheid
authors.affiliation: The Interdepartmental Graduate Program in Nutritional Sciences, Iowa State University, Ames, IA, USA; Department of Kinesiology, Iowa State University, Ames, IA, USA.
authors.forename: Kelly N Z
authors.initials: KNZ
authors.lastname: Fuller
authors.affiliation: Department of Kinesiology, Iowa State University, Ames, IA, USA.
authors.forename: Rudy J
authors.initials: RJ
authors.lastname: Valentine
authors.affiliation: Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA.
authors.forename: Shu En
authors.initials: SE
authors.lastname: Leow
authors.affiliation: Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA.
authors.forename: Leah
authors.initials: L
authors.lastname: Reed
authors.affiliation: Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA.
authors.forename: Emily
authors.initials: E
authors.lastname: Wisecup
authors.affiliation: The Interdepartmental Graduate Program in Nutritional Sciences, Iowa State University, Ames, IA, USA; Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA.
authors.forename: Kevin L
authors.initials: KL
authors.lastname: Schalinske
authors.affiliation: The Interdepartmental Graduate Program in Nutritional Sciences, Iowa State University, Ames, IA, USA; Department of Food Science and Human Nutrition, Iowa State University, Ames, IA, USA. Electronic address: mrowling@iastate.edu.
authors.forename: Matthew J
authors.initials: MJ
authors.lastname: Rowling
mesh_terms: D052242:Adiponectin / Q000097:blood*; D050154:Adiposity; D000804:Angiotensin II / Q000097:blood; D000818:Animals; D001786:Blood Glucose / Q000032:analysis; D002112:Calcifediol / Q000097:blood*; D003924:Diabetes Mellitus, Type 2 / Q000097:blood / Q000503:physiopathology*; D004040:Dietary Carbohydrates / Q000008:administration & dosage*; D015870:Gene Expression; D006442:Glycated Hemoglobin / Q000032:analysis; D007328:Insulin / Q000097:blood; D007668:Kidney / Q000503:physiopathology*; D008297:Male; D008565:Membrane Proteins / Q000235:genetics; D051381:Rats; D011924:Rats, Zucker; D012084:Renin-Angiotensin System / Q000187:drug effects / Q000502:physiology; D015398:Signal Transduction; D013213:Starch / Q000008:administration & dosage* / Q000378:metabolism
chemical_list: D052242:Adiponectin; D000804:Angiotensin II; D001786:Blood Glucose; D002112:Calcifediol; D004040:Dietary Carbohydrates; D006442:Glycated Hemoglobin; D007328:Insulin; D008565:Membrane Proteins; D013213:Starch; C113267:nephrin
keywords: Adiponectin; Renin-angiotensin system; Resistant starch; Type 2 diabetes; Vitamin D; Zucker diabetic fatty rat