Prolonged, low dose alpha-tocopherol therapy counteracts intercellular cell adhesion molecule-1 activation

Abstract

Background: Up-regulation of ICAM-1 at the vascular endothelial level is one of the most important promoters in the slow progression of a healthy vessel to an atherosclerotic one. The current study aimed to evaluate whether low dose of the antioxidant alpha-tocopherol affects the circulating soluble (s) ICAM-1 in healthy subjects.

Methods: Either alpha-tocopherol E (50 I.U./day) or placebo was randomly, double-blindly given to 39 healthy male volunteers (mean age 41.6+/-5.9 years) over a period of 20 weeks.

Results: At the baseline, sICAM-1 levels were inversely correlated with alpha-tocopherol concentrations (r=-0.525, p<0.0001). Twenty weeks of alpha-tocopherol supplementation (n=20 subjects) significantly decreased the circulating sICAM-1 levels (from 149.2+/-18.4 to 131.5+/-17.2 microg l(-1), p<0.004) while it increased the alpha-tocopherol concentrations (from 25.8+/-5.0 to 31.2+/-5.7 micromol l(-1), p<0.003). No significant changes in plasma sICAM-1 and alpha-tocopherol levels were observed in placebo-treated subjects (n=19). In actively treated subjects, changes in circulating sICAM-1 were inversely correlated with changes in alpha-tocopherol concentrations (r=-0.597, p=0.005).

Conclusions: Plasma sICAM-1 concentrations are stable in healthy subjects over a period of 20 weeks while they significantly decreased with low dose of alpha-tocopherol. Thus, antioxidant vitamins are likely to counteract with endothelial changes that could potentially trigger the atherogenetic process.