Short-term treatment with L-arginine prevents the smoking-induced
impairment of endothelial function and vascular elastic properties in
young individuals
Background: L-arginine, the substrate for endothelial nitric oxide
synthase, is essential for normal endothelial function. Aim of the
present study was to investigate in healthy smokers the effect of a
short-term daily L-arginine administration on vascular function.
Methods: We studied the effect of a 3-day oral administration of
L-arginine in 10 healthy smokers (24.3 +/- 0.73 years old) on 3
occasions (day0, day1 and day3). The study was carried out on two
separate arms, one with L-arginine (7 gr/d) and one with placebo
according to a randomized, placebo-controlled, double-blind, cross-over
design. Measurements were carried out before, immediately after (Sm0)
and 20 min after (Sm20) cigarette smoking. Endothelial function was
evaluated by flow-mediated dilatation (FMD) of the brachial artery.
Carotid-femoral pulse wave velocity (PWV) was measured as an index of
aortic stiffness and augmentation index (AIx) as a measure of arterial
wave reflections.
Results: Compared to placebo, L-arginine led to an increase of FMD
(p<0.05 at day 2), indicating a favorable effect on endothelial
function, which however lost significance at day 3. L-arginine induced a
progressive decrease of PWV and AIx at both day 2 and day 3 (p<0.01 vs
baseline for all). L-arginine blunted the acute smoking-induced increase
of AIx at both day 1 (p<0.05) and day 3 (p<0.01), and there was a trend
to protect the smoking-induced change of PWV at day 3 (p<0.1).
Conclusions: Short-term daily administration of L-arginine improves
arterial performance in healthy smokers and abrogates the
smoking-induced increase in arterial stiffness and wave reflections in
these individuals. (C) 2007 Elsevier Ireland Ltd. All rights reserved
