The relationship between oxidized lipoprotein(a) and carotid atherosclerosis in asymptomatic subjects: A comparison with native lipoprotein(a)

BACKGROUND: Oxidized lipoprotein(a) (oxLp(a)) can be a more potent marker of atherogenesis than native Lp(a), although Lp(a) is considered to be a risk factor for atherosclerotic diseases. Limited clinical data are available regarding the significance of oxLp(a) in atherosclerotic manifestations. This study aimed to investigate the association between the serum oxLp(a) and carotid artery intima-media thickness (CIMT), in comparison to the serum Lp(a) levels, among asymptomatic subjects. METHODS: The atheroscrerosis-related variables including Lp(a) and oxLp(a) were measured in 136 cardiovascular disease-free subjects (61 males and 75 females, mean age of 64 years). The serum oxLp(a) level was quantified using a sandwich ELISA system. The CIMT level was ultrasonographically measured on bilateral carotid arteries. RESULTS: The median level of Lp(a) was 120 μmol/L, oxLp(a) was 0.06 nmol/L, and CIMT was 0.7 mm, respectively. A simple correlation test showed that the CIMT was significantly and positively correlated with age, systolic blood pressure and oxLp(a) (r = 0.208, P < 0.05). A multiple linear regression analysis revealed that oxLp(a) continued to show a significant and positive correlation with the CIMT (β = 0.202, P = 0.01). Although the similar analyses were conducted for Lp(a), it showed only a weak correlation with the CIMT (r = 0.011, β = 0.041, both P < 0.05). CONCLUSIONS: These results suggest that oxLp(a) may be more closely associated with accelerated carotid atherosclerosis, in comparison to Lp(a), in this population. This finding can be important for obtaining a better understanding of the different atherogenic roles played by oxLp(a) in comparison to Lp(a).