#22 THIAMINE (VITAMIN B1) PROTECTS AGAINST
HIGH GLUCOSE AND INSULIN MEDIATED PROLIFERATION OF HUMAN
INFRAGENICULAR ARTERIAL SMOOTH MUSCLE CELLS.
Ricardo Avena, MD, Subodh Arora, MD, Brennan J. Carmody, MD, Kenyatta
Cosby, BS, and Anton N. Sidawy, MD
Veterans Administration Medical Center, Washington, D.C.
Objective: Accelerated proliferation of vascular smooth
muscle cell (VSMC) plays an important role in the development of
atherosclerosis which preferentially affects the infragenicular
vasculature in patients with diabetes mellitus. High insulin and
glucose levels, which are present in patients with type II diabetes,
have an additive effect in infragenicular VSMC proliferation
in-vitro. Thiamine is a co-enzyme important in intracellular glucose
metabolism. The objective of this study is to determine the effect
of Thiamine on human infragenicular VSMC proliferation induced by
high glucose and insulin levels in-vitro.
Methods: Human infragenicular VSMC isolated from diabetic
patients undergoing lower extremity amputation were used. Cells were
cultured at 37°C in 5% CO2. Cells were identified as VSMC by
immunohistochemical analysis. 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 mM of Thiamine. Standard hemocytometry and
3H-thymidine incorporation quantified cell proliferation after
incubation for 6 days and 24 hours, respectively.
Results: Cell count and DNA synthesis, as reflected by
3H-thymidine incorporation, significantly increased in all cell
groups growing in glucose concentration of 0.1% with insulin of 1000
ng/ml and in all groups growing in 0.2% glucose with and without
insulin (*=p<0.05). This proliferation effect was inhibited by
Thiamine (+=p<0.05).
Conclusions: These data suggest that thiamin inhibits human
infragenicular VSMC proliferation induced by high glucose and
insulin. Vitamin B1 intake may prove important in delaying the
atherosclerotic complications of diabetes.
