The Impact of Oral L-Arginine Supplementation on Acute Smoking-Induced Endothelial Injury and Arterial Performance

BACKGROUND Smoking is associated with endothelial dysfunction and increased inflammatory status. The amino acid L-arginine, improves endothelial function in patients with cardiovascular risk factors. We investigated the effect Of L-arginine on vascular function and inflammatory process in healthy smokers at rest and after acute smoking. METHODS We studied the effect Of L-arginine and/or placebo in 12 healthy young smokers on three occasions (day 0, day 1, and day 3). The study was carried out on two separate arms, one with L-arginine (3 x 7 g/day) and one with placebo, according to a randomized, placebo-controlled, double-blind, cross-over design. Measurements were carried out before, immediately after, and 20 min after cigarette smoking. Endothelial function was evaluated by flow-mediated dilation (FMD). Carotid-femoral,pulse wave velocity (PWV) was measured as an index of aortic stiffness and augmentation index (AIx) and as a measure of arterial wave reflections. Serum soluble intercellular adhesion molecule-1 (sICAM-1) was measured. RESULTS Compared to placebo, L-arginine improved FMD (P < 0.01 at day I and P < 0.05 at day 3). L-Arginine reduced PWV and AN at both days 1 and 3 (P < 0.05 vs. baseline). L-Arginine blunted the acute smoking-induced increase of AIx at both day 1 (P < 0.05) and day 3 (P < 0.01), and prevented the smoking-induced elevation of PWV at day 3 (P < 0.05). Importantly, L-arginine reduced sICAM-1 at days 1 and 3 (P < 0.05 for both vs. baseline). CONCLUSIONS Oral L-arginine improves endothelial function and vascular elastic properties of the arterial tree during the acute phase of smoking, an effect accompanied by reduced sICAM-1 levels in these subjects. Am J Hypertens 2009; 22:586-592 (C) 2009 American Journal of Hypertension, Ltd.