Thiamine (vitamin B1) protects against glucose- and insulin-mediated proliferation of human infragenicular arterial smooth muscle cells

Accelerated proliferation of arterial smooth muscle cells (ASMC) plays an i mportant role in the development of atherosclerosis, which preferentially a ffects the infragenicular vasculature in patients with diabetes mellitus. H igh insulin and glucose levels, which are present in patients with type II diabetes, have an additive effect in infragenicular ASMC proliferation in v itro. Thiamine is a coenzyme important in intracellular glucose metabolism. The objective of this study is to determine the effect of thiamine on huma n infragenicular ASMC proliferation induced by high glucose and insulin lev els in vitro. Human infragenicular ASMC isolated from diabetic patients und ergoing lower extremity amputation were used. Cells were cultured at 37 deg rees C in 5% CO2. Cells were identified as ASMC by immunohistochemical anal ysis. Cells from passages 3-5 were exposed to glucose concentrations of 0.1 and 0.2% with and without insulin concentrations of 100 ng/mL and 1000 ng/ mL, in the presence or absence of 200 CIM of thiamine. Standard hemocytomet ry and H-3-thymidine incorporation quantified cell proliferation after incu bation for 6 days and 24 hr, respectively. The data suggest that thiamine i nhibits human infragenicular ASMC proliferation induced by high glucose and insulin. Vitamin B1 intake may prove important in delaying the atheroscler otic complications of diabetes. DOI: 10.1007/s100169910007.