28-LB: Role of Glycine N-methyltransferase in Electronegative Lipoproteins-Induced Vascular Dysfunction in a Diabetic Rodent Model

Several studies showed low-density lipoprotein (LDL) is associated with high risk of atherosclerosis in patients with diabetes. However, aggressively decreasing total LDL does not prevent all vascular complications. A novel culprit electronegative LDL (L5) was significantly increased in diabetic patients and could induce vascular damage according to our previous studies. However, the mechanism of L5 formation and how to reduce plasma L5 level are still unclear. In the present study, we found both aqueous and ethylacetate extracts of a traditional Chinese remedy Artemisia capillaris (AC) could decrease plasma L5 level in western diet-fed hamster (22.45 and 28.64 vs. 56.83%, respectively), while clinical remedies Simvastatin and Niacin could not. AC could also reverse western diet-induced vascular senescence (b-gal staining) and relaxation dysfunction in aortic rings (63.66±2.14 vs 40.13±1.48% of maximum contraction when compared to western diet hamsters; P<0.01). To further determine the underlying mechanism, we have found that AC reversed western diet-reduced Glycine N-methyltransferase (GNMT) protein abundance and altered several microRNA expression by analyzing the microarray heatmap in liver tissue.

In conclusion, AC could significantly reverse western diet-induced vascular injury by lowering plasma L5 level through restore the liver enzyme GNMT activity.