Oxidized LDL and C-reactive protein level in relation to carotid intima-media thickness in population with risk factors for atherosclerosis

Abstract

Introduction: Elevated levels of oxidized LDL cholesterol (OxLDL) are considered to be a key factor of initiating and accel erating atherosclerosis. It promotes atherosclerosis through inflammatory and immunologic mechanisms that lead to the formation of macrophage foam cells. Objective: To determine the relationship among OxLDL, C-reactive protein (CRP) level and carotid intima-media thick ness (IMT) in population with risk factors for atherosclerosis. Methods: The study group consisted of 125 clinically healthy, hypercholesterolaemic subjects (49.3±5.7 years; 75 females and 50 males) compared with 100 age-matched population-based control subjects. The study group was divided into two subgroups: subgroup A (the levels of LDL cholesterol > 5 mmol/L) and subgroup B (the levels of LDL cholesterol <5 mmol/L). None of the subjects had history of cerebrovascu lar, ischaemic heart disease, hypertension or diabetes mellitus. Lipid profiles were measured by enzymatic methods. OxLDL was measured by using a specific monoclonal antibody, mAb4E6. CRP was measured using hemiluminescent methods (Immulite - DPC). The common carotid IMT was measured by the B-mode ultrasound. Results: Compared to controls, the study group had higher levels of OxLDL (119.97±43.15 vs. 82.03±25.99 IU/L; p<0.01) and CRP (6.20±3.55 vs. 2.68±3.04 mg/ml; p<0.05). IMT was significantly higher in study subjects (1.14±0.38 vs. 0.72±0.24 mm; p<0.05). We also found that, in the whole study group, IMT significantly positively correlated with OxLDL (r=0.442; p<0.05). We found that in the study subgroup A, IMT positively correlated with CRP (r=0.792; p<0.01). In controls, we found a significantly positive association between IMT and OxLDL (r=0.781; p<0.01) and CRP (r=0.748; p<0.01). Conclusion: The elevated levels of OxLDL and CRP are associated with higher common carotid intima-media thickness in population with risk factors for atherosclerosis.