Effects of vitamin D on serum levels and gene expression of enzymes aldose reductase, o-linked n-acetyl glucosamine transferase and glutamine fructose-6-phosphate aminotransferase in patients with type 2 diabetes: a randomized, double blind, placebo controlled clinical trial

Although vitamin D deficiency has been associated with diabetes complications, the underlying mechanisms have not been clarified in human studies yet. This clinical trial was designed to evaluate the effect of vitamin D supplementation on serum levels and gene expression of some polyols and hexamine pathway enzymes, which play pivotal roles in the incidence of diabetes complications. Seventy-four patients with type 2 diabetes were randomly divided into two groups as receiving vitamin D (100 mu g/d equal to 4000 IU/d) or placebo for a 3-month period. Moreover, serum levels of insulin, fasting plasma glucose (FPG), vitamin D, HbA1c, aldose reductase (AR), O-linked N-acetyl glucosamine transferase (OGT), and glutamine fructose -6-phosphate aminotransferase (GFPT), as well as the gene expression of mentioned enzymes in PBMCs were measured before and after the intervention. After 3-months intervention, 25 (OH) vitamin D level significantly increased in the vitamin D group. The expression of AR and GFPT genes significantly decreased and some significant differences were observed regarding the serum level of AR enzyme. Additionally, insulin showed significant increase following vitamin D intake. Our result show that, receiving 100 mu g/d vitamin D in type 2 diabetes patients, for a 3-month period might be helpful for ameliorating diabetes complications not only by improving insulin level, but also by suppressing AR and GFPT gene expressions in PBMC.

Automated summary

The study found that 100 µg/day vitamin D supplementation in type 2 diabetes patients for 3 months significantly increased vitamin D levels, insulin levels, and decreased aldose reductase and glutamine fructose-6-phosphate aminotransferase gene expressions.