Lack of association between oxidized LDL-cholesterol concentrations and haptoglobin phenotypes in healthy subjects

BACKGROUND: The haptoglobin (Hp) 2-2 phenotype has been known to have less antioxidative activity than Hp 1-1 and Hp 2-1. However, few have reported the relationship between oxidative stress and Hp phenotypes by using oxidized LDL. The relationship between Hp phenotypes and oxidative stress was therefore investigated in healthy adults. METHODS: The serum Hp concentrations, albumin, uric acid, iron, L-ascorbic acid, total antioxidant status and oxidized LDL concentrations were measured and analysed in 200 healthy Korean men and women with Hp 2-1 and Hp 2-2 phenotypes. RESULTS: The serum concentrations of Hp were significantly higher in the Hp 2-1 compared with the Hp 2-2 phenotype. However, serum concentrations of total antioxidant status and oxidized LDL did not show any statistical differences in either sex. The L-ascorbic acid concentrations in serum showed lower values in the Hp 2-2 compared with the Hp 2-1 phenotype, for both sexes (P < 0.05). CONCLUSIONS: The concentration of L-ascorbic acid, the first line antioxidant, was lower in the Hp 2-2 than in the Hp 2-1 phenotype; this did not significantly affect the total antioxidant status, and there was no significant difference in oxidized LDL for either group in healthy adults.