Diabetic hemodialysis: vitamin D supplementation and its related signaling pathways involved in insulin and lipid metabolism.

Abstract

BACKGROUND\nWe assessed the effects of vitamin D supplementation on the associated molecular mechanisms that are involved in insulin and lipid metabolism of diabetic hemodialysis (HD).\n\n\nMETHODS\nA double-blind, randomized, placebo-controlled clinical trial was carried out in 55 patients with diabetic HD. In the current project, we were used two groups which each subject received vitamin D supplements (50,000 IU, n=28) or placebo (50,000 IU, n=27) every 2 weeks for 12 weeks. Gene expression analyses (RT-PCR) were included to obtain the rate of gene expression of the related insulin and lipid metabolism genes in peripheral blood mononuclear cells (PBMCs) of patients with diabetic HD.\n\n\nRESULTS\nOur data revealed that consumption of vitamin D supplementation enables to over express the peroxisome proliferation-activated receptor gamma (PPAR-γ) (P=0.001), AKT (P=0.04), PI3K (P=0.02), insulin receptor substrate-1 (IRS1) (P0.008) and glucose transporter type 4 (GLUT-4) (P=0.01) and down regulate expression of protein kinase C (PKC) (P=0.001) in the cases with diabetic HD than control group following the 12-week intervention. In addition, vitamin D supplementation down regulated low density lipoprotein receptor (LDLR) (P=0.03) expression in the subjects with diabetic HD than the control group. Vitamin D supplementation did not observe any effects on expression of pyruvate dehydrogenase kinase 1 (PDK1) (P=0.37), IRS2 (P=0.90) and lipoprotein (a) [Lp(a)] (P=0.05).\n\n\nCONCLUSIONS\nOur findings confirmed, diabetic HD subjects who were received the vitamin D supplementation (for 12 weeks), show a significant over expression in the PPAR-γ, AKT, PI3K, IRS1 and GLUT4 genes, and also show a significant down regulation in the PKC and LDLR genes. Moreover, did not observe any effects on PDK1, IRS2 and Lp(a) expression.