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

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.

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.

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).

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.