A New Biomarker for CVD in HIV-Infected Patients

Rajesh T. Gandhi, MD reviewing Mangili A et al. Clin Infect Dis 2014 Mar 15.

 

Lipoprotein-associated phospholipase A2 is frequently elevated in HIV-infected patients and is associated with surrogate markers of cardiovascular disease.

 

Blood levels of lipoprotein-associated phospholipase A2 (Lp-PLA2), an inflammatory enzyme found in atherosclerotic plaques, have been shown to predict risk for cardiovascular disease (CVD) in the general population. Unlike C-reactive protein, Lp-PLA2 is not affected by systemic inflammation, which may make it particularly useful for assessing cardiovascular risk in patients with chronic infectious diseases. Now, investigators have measured this enzyme in HIV-infected patients and assessed its relation to surrogate markers of atherosclerosis.

Lp-PLA2 activity and mass were measured on frozen blood samples from 341 HIV-infected adults. Samples from 75% of the participants showed abnormal Lp-PLA2 mass. Higher Lp-PLA2 activity — but not mass — was correlated with higher Framingham Risk Score. Lp-PLA2 activity also correlated, albeit weakly, with internal carotid intima–media thickness (r=0.12, P=0.04). Patients with higher coronary artery calcium scores (measured using specialized computed tomography) had significantly higher Lp-PLA2 mass than those with lower scores. In multivariable analysis adjusted for other cardiovascular risk factors, antiretroviral therapy and HIV protease inhibitor use were each positively associated with Lp-PLA2 activity and mass. The addition of Lp-PLA2 to standard cardiovascular risk factors improved the ability to predict common carotid (but not internal carotid or coronary) atherosclerosis.

COMMENT

This intriguing cross-sectional study suggests that a novel inflammatory biomarker, lipoprotein-associated phospholipase A2, is frequently elevated in HIV-infected people and is associated with surrogate markers of cardiovascular disease. Longitudinal studies are necessary to determine whether elevated Lp-PLA2 predicts changes in surrogate CVD markers — and, most importantly, the occurrence of cardiovascular events — in such individuals. Drugs that lower Lp-PLA2levels are in clinical trials and, if successful in preventing atherosclerosis, may be particularly useful in HIV-infected patients. For now, although testing for this marker is available through commercial labs, it is not in widespread use for screening of the general population, and I would not order it on my HIV-infected patients until we have more information.

CITATION(S):

  1. Mangili A et al. Lipoprotein-associated phospholipase A2, a novel cardiovascular inflammatory marker, in HIV-infected patients. Clin Infect Dis2014 Mar 1558:893. (http://dx.doi.org/10.1093/cid/cit815)