Elevated Microparticle Tissue Factor Activity is Associated with Carotid Artery Plaque in HIV Infected Women.

BACKGROUND: Expression of tissue factor (TF) on the surface of activated monocytes may trigger thrombosis, leading to clotting risk, inflammation, and atherosclerosis. TF-positive microparticles (MP-TF) represent a functionally active form of TF that may be promulgated by long-term HIV infection. We hypothesized that greater MP-TF activity is associated with carotid artery plaque in HIV+ women.

SETTING: In a case-control study nested within the Women's Interagency HIV Study (WIHS), eligible HIV+ participants underwent B-mode carotid artery ultrasound at 2 study visits occurring 7 years apart. Cases were defined by presence of at least 1 carotid artery plaque assessed at either visit. Cases were matched 1:2 to controls who were found not to have carotid artery plaques.

METHODS: Conditional logistic regression estimated the association of MP-TF activity with presence of carotid artery plaque, adjusting for demographic and behavioral characteristics, HIV-related factors, cardiometabolic risk factors, and serum inflammation biomarkers (hsCRP, IL-6, sCD14, sCD163, Gal-3, Gal-3BP).

RESULTS: Elevated MP-TF activity (>0.537 pg/mL) was found to be significantly associated with greater odds of plaque (adjusted odds ratio 3.86, 95% CI 1.06-14.07, p=0.04). The association was attenuated after further adjustment for IL-6, but was unaffected by adjustment for other biomarkers including those denoting monocyte activation.

CONCLUSIONS: Our findings suggest a link among HIV infection, innate immune system perturbation, coagulation, and atherosclerosis.