Effect of vitamin D on insulin resistance and tissue inflammation in western and control diet‐fed mice (1108.7)

INTRODUCTION: Pandemic Vitamin D (VitD) deficiency is associated with low‐grade chronic inflammation and type 2 diabetes. We hypothesize that vitD could inhibit the inflammatory response and increase the insulin sensitivity. METHODS: 6‐7 week old, male C57BL/6J mice were fed with ± VitD control (CD; 10% fat) or Western (WD; 41% fat) diets for 15 weeks. The VitD deficient (VDD) control and obese mice were further subdivided into two groups. One group was supplemented with vitD (i.p 50ng/mouse/3x/week), the other with saline for 4 weeks. ITT and GTT performed before and after supplementation. Cytokines and tissue inflammatory gene expressions were analyzed. RESULTS: In both VDD CD & WD groups 25‐OH‐vitD levels were reduced compared to controls CD & WD (6.3±1.5; 23.5±0.8 vs 93±5.4; 113.1±9.4, P <0.05), and after supplementation levels were significantly increased (73.3±7.8; 62.1±2.6). Both VDD groups and WD mice had an impaired glucose tolerance compared to the CD mice. After VitD supplementation insulin resistance was reduced and glucose tolerance improved. In addition reduced inflammatory cytokines (IL‐1β: 27.2±8.1 vs 167.6±91.9; RANTES: 79.5±13.3 vs 154±69.7) in CD VDD mice but not in WD‐VDD mice. CONCLUSION: VitD deficiency in both CD and WD fed mice groups induced insulin resistance. Supplementation with VitD in the CD‐VDD improved insulin sensitivity and reduced inflammation, but a similar effect has not been observed in the VDD obese mice. Grant Funding Source : Supported by Academy of Finland, EVO & Finnish Cultural Foundation North Ostrobothnia Regional funds