Effects of methionine-induced hyperhomocysteinemia on endothelium-dependent vasodilation and oxidative status in healthy adults

Homocysteine-mediated endothelial dysfunction has been proposed to occur via oxidative stress mechanisms in humans. However, there is controversy regarding the effects of homocysteine on endothelial function and oxidative status, which may in part result from age discrepancy across the studies. The present study was designed to investigate the aging effect on the relationship between endothelium-dependent vasodilation and oxidative status in methionine-induced hyperhomocysteinemia. Plasma homocysteine, phosphatidylcholine hydroperoxide (PCOOH), P-selectin levels, and brachial artery flow-mediated vasodilation were measured at baseline and 4 hours after an oral methionine load (0.1 g/kg) in 15 younger (21 to 40 years) and 15 older (55 to 70 years) healthy adults. Homocysteine increased from 7.3+/-1.3 micromol/L at baseline to 22.7+/-5.2 micromol/L at 4 hours in younger (P