Background: This study was conducted to determine the effects of vitamin D
supplementation on some of the gene expressions related to insulin and lipid
metabolism in diabetic hemodialysis (HD) patients.
Methods: A double-blind, randomized, placebo-controlled clinical trial was carried out in
55 patients with diabetic HD. The current project used two groups in 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.
Results: Our data revealed that consumption of vitamin D supplementation enables to
overexpress 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 downregulate the expression of
protein kinase C (PKC) (P=0.001) in patients with diabetic HD than control group
following the 12-week intervention. In addition, vitamin D supplementation
downregulated low-density lipoprotein receptor (LDLR) (P=0.03) expression in the
subjects with diabetic HD than the control group. Vitamin D supplementation did not
show any effects on the expression of pyruvate dehydrogenase kinase 1 (PDK1)
(P=0.37), IRS2 (P=0.90) and lipoprotein (a) [Lp(a)] (P=0.05).
Conclusion: Our findings confirmed that diabetic HD subjects who received the vitamin
D supplementation (for 12 weeks), showed a significant overexpression in the PPAR-γ,
AKT, PI3K, IRS1 and GLUT4 genes, and also showed a significant downregulation in
the PKC and LDLR genes. Moreover, no effects on PDK1, IRS2 and Lp(a) expression