Introduction Plasma triglycerides (TG) and HDL-C are inversely related in Metabolic Syndrome (MetS), due to exchange of VLDL-TG for HDL-cholesteryl esters catalyzed by cholesteryl ester transfer protein (CETP). We investigated the relationship of TG to HDL-C in highly-active antiretroviral drug (HAART)-treated HIV patients. Methods Fasting plasma TG and HDL-C levels were compared in 179 hypertriglyceridemic HIV/HAART patients and 71 HIV-negative persons (31 normotriglyceridemic (NL) and 40 hypertriglyceridemic due to type IV hyperlipidemia (HTG)). CETP mass and activity were compared in 19 NL and 87 HIV/HAART subjects. Results Among the three groups, a plot of HDL-C vs. TG gave similar slopes but significantly different y-intercepts (9.24 ± 0.45, 8.16 ± 0.54, 6.70 ± 0.65, sqrt(HDL-C) for NL, HIV and HTG respectively; P<0.001); this difference persisted after adjusting HDL-C for TG, age, BMI, gender, glucose, CD4 count, viral load and HAART strata (7.18 ± 0.20, 6.20 ± 0.05 and 4.55 ± 0.15 sqrt(HDL-C) for NL, HIV and HTG, respectively, P <0.001). CETP activity was not different between NL and HIV, but CETP mass was significantly higher in HIV (1.47 ± 0.53 compared to 0.93 ± 0.27 μg/mL, P<0.0001), hence CETP specific activity was lower in HIV (22.67 ± 13.46 compared to 28.46 ± 8.24 nmol/μg/h, P=0.001). Conclusions Dyslipidemic HIV/HAART patients have a distinctive HDL-C plasma concentration adjusted for TG. The weak inverse relationship between HDL-C and TG is not explained by altered total CETP activity; it could result from a non-CETP-dependent mechanism or a decrease in CETP function due to inhibitors of CETP activity in HIV patients’ plasma.

Objective HIV patients on antiretroviral therapy (HIV/ART) exhibit a unique atherogenic dyslipidemic profile with hypertriglyceridemia (HTG) and low plasma concentrations of high density lipoprotein-cholesterol (HDL-C). In the Heart Positive Study of HIV/ART patients, a hypolipidemic therapy of fenofibrate, niacin, diet, and exercise reduced HTG and plasma non-HDL-C concentrations and raised plasma HDL-C and adiponectin concentrations. We tested the hypothesis that HIV/ART HDL have abnormal structures and properties and are dysfunctional. Approach and Results Hypolipidemic therapy reduced the TG contents of LDL and HDL. At baseline, HIV/ART low density lipoproteins (LDL) were more triglyceride (TG)-rich and HDL were more TG- and cholesteryl ester (CE)-rich than the corresponding lipoproteins from normolipidemic (NL) subjects. Very low density lipoproteins, LDL and HDL were larger than the corresponding lipoproteins from NL subjects; HIV/ART HDL were less stable than NL HDL. HDL-[3H]CE uptake by Huh7 hepatocytes was used to assess HDL functionality. HIV/ART plasma were found to contain significantly less competitive inhibition activity for hepatocyte HDL-CE uptake than did NL plasma (p<0.001). Conclusion Compared to NL subjects, lipoproteins from HIV/ART patients are larger and more neutral lipid-rich, and their HDL are less stable and less receptor-competent. Based on this work and previous studies of lipase activity in HIV, we present a model in which plasma lipolytic activities and/or hepatic CE uptake are impaired in HIV/ART patients. These findings provide a rationale to determine whether the distinctive lipoprotein structure, properties and function of HIV/ART HDL predict atherosclerosis as assessed by carotid artery intimal medial thickness.