Serum carotenoids and vitamins in relation to markers of endothelial function and inflammation.

Background: Endothelial cell dysfunction may be related to an increase in cellular oxidative stress. Carotenoids and vitamins could have an antioxidant-mediated tempering influence on endothelial function and inflammation, thereby reducing the risk of atherosclerosis.
Methods: We measured serum carotenoids, alpha-tocopherol and Vitamin C concentrations in 379 subjects sampled from the general population. High-sensitive C-reactive protein (CRP), fibrinogen (Fbg) and leukocytes were measured as markers of inflammation. Furthermore, soluble intercellular adhesion molecule-1 (sICAM-1) and flow-mediated vasodilation (FMD; n= 165) were measured as markers of endothelial function. Relationships between serum carotenoids and vitamins and markers of endothelial function and inflammation were analysed after adjustment for confounding.
Results: In the total study group, lutein and lycopene were inversely related to sICAM-1 with regression-coefficients of -0.38+/-0.19 (p = 0.04) and -0.16+/-0.08 (p = 0.04) per 1 micromol/l, respectively. beta-Carotene was inverse related to leukocytes (-0.23+/-0.07; p = 0.007) and CRP (-1.09+/-0.30; p = 0.0003) per 1 micromol/l. Vitamin C was inverse related to CRP (-0.01+/-0.005; p = 0.04) per 1 micromol/l, whereas alpha-tocopherol was positively related to CRP (0.03+/-0.01; p = 0.02) per 1 micro/l. Zeaxanthin was inversely related to FMD (31.2+/-15.3; p = 0.04) per 1 micromol/l.
Conclusion: The inverse relations between carotenoids, Vitamin C and sICAM-1, CRP and leukocytes may help to explain the possible protective effect of carotenoids and Vitamin C on atherosclerosis through an influence on inflammatory processes and endothelial function.