Arterial stiffness is rapidly induced by raising the plasma homocysteine concentration with methionine

Homocysteine appears to be causally related to cardiovascular disease and shown to induce endothelial dysfunction. An adverse effect on large elastic arteries has not been reported. In 18 healthy middle-aged subjects, systemic arterial compliance (SAC) was measured over 5 h after a standard methionine load. Arterial pressure waves from the carotid artery and aortic flow were measured non-invasively and SAC calculated. Differences in mean SAC values when plasma homocysteine concentrations were raised with a methionine containing meal and on another day when a control meal was eaten were highly significant. SAC fell (arterial stiffness increased) by 22% at 2.5 h and by 19% at 5 h (treatment×time interaction: P=0.003 and 0.004, respectively). Adjustment for confounders (age, arterial pressure, BMI, LDL cholesterol) did not affect conclusions. Thus, arterial stiffness in the central elastic arterial system increased rapidly at high plasma homocysteine concentrations.