Restoration of endothelium-dependent relaxation in both hypercholesterolemia and diabetes by chronic taurine

We examined the effects of taurine on levels of low-density lipoprotein (LDL) cholesterol and glucose, and an endothelium-dependent relaxation in response to acetylcholine in cholesterol-fed or streptozotocin-induced diabetic mice. The acetylcholine-induced concentration-dependent relaxation was significantly attenuated in aortic rings from cholesterol-fed and streptozotocin-induced diabetic mice. The attenuated vasodilation in both cholesterol-fed and streptozotocin-induced diabetic mice was normalized by the chronic administration of taurine. The endothelium-independent relaxation of aortic rings induced by sodium nitroprusside was not significantly different between control, cholesterol-fed and streptozotocin-induced diabetic mice. The increased serum levels of LDL cholesterol in cholesterol-fed and diabetic mice were returned to normal by the chronic administration of taurine. The chronic administration of taurine had no effects on serum glucose levels. These results suggest that the impaired endothelium-dependent vasodilation seen in both cholesterol-fed and streptozotocin-diabetic mice can be normalized by the chronic administration of taurine and this effect may be, at least in part, due to lowering of serum LDL levels.