Lipoprotein-associated phospholipase A2 and cardiovascular disease risk in HIV infection.

OBJECTIVES: HIV-infected patients on antiretroviral therapy (ART) have an increased cardiovascular disease (CVD) risk as a result of heightened inflammation and immune activation, despite at times having normal lipids and few traditional risk factors. Biomarkers are needed to identify such patients before a clinical event. Lipoprotein-associated phospholipase A2 (Lp-PLA2 ) predicts CVD events in the general population. This study investigated the relationship between Lp-PLA2 and markers of CVD risk, systemic inflammation, immune activation, and coagulation in HIV infection.

METHODS: One hundred subjects on stable ART with normal fasting low-density lipoprotein (LDL) cholesterol were enrolled in the study. Plasma Lp-PLA2 concentrations were measured by enzyme-linked immunosorbent assay (ELISA; > 200 ng/mL was considered high CVD risk). Subclinical atherosclerosis, endothelial function, inflammation, immune activation and fasting lipids were also evaluated.

RESULTS: The median age of the patients was 47 years and 77% were male. Median (range) Lp-PLA2 was 209 (71-402) ng/mL. Fifty-seven per cent of patients had Lp-PLA2 concentrations > 200 ng/mL. Lp-PLA2 was positively correlated with soluble markers of inflammation or immune activation (tumour necrosis factor receptor-II, intercellular and vascular cellular adhesion molecules, and CD14; all R = 0.3; P < 0.01), and negatively correlated with coagulation markers (D-dimer and fibrinogen; both R = -0.2; P < 0.04). Lp-PLA2 was not correlated with lipids, coronary artery calcium score, or flow-mediated vasodilation, but trended towards a significant correlation with carotid intima-media thickness (R = 0.2; P = 0.05).

CONCLUSIONS: In this population with stable ART and normal LDL cholesterol, Lp-PLA2 was in the high CVD risk category in the majority of subjects. Lp-PLA2 appears to be associated with inflammation/immune activation, but also with anti-thrombotic effects. Lp-PLA2 may represent a valuable early biomarker of CVD risk in HIV infection before subclinical atherosclerosis can be detected.