Increased cholesterol absorption rather than synthesis is involved in boosted protease inhibitor-associated...

The aim of this study was to compare the differential effects of first-line efavirenz (EFV)-based vs. boosted lopinavir-based antiretroviral regimens on cholesterol metabolism.

Multicentre, open-label, randomized clinical trial.

Forty-nine naive HIV-infected patients were randomized (1 : 1) to receive either ritonavir-boosted lopinavir (LPV/r) or EFV both in combination with tenofovir and emtricitabine (ClinicalTrials.gov: NCT00759070). Lipid profile and serum phytosterols and cholesterol precursors were determined at baseline and after 16 weeks.

After 16 weeks of intervention, total and non-HDL cholesterol as well as triglyceride levels significantly increased in the LPV/r-group (+1.0 ± 0.8; +0.8 ± 0.7 and +0.8 ± 1.5 mmol/l, respectively), but not in the EFV-group (+0.4 ± 0.7; +0.4 ± 0.6 and 0.2 ± 0.5 mmol/l, respectively). Markers of cholesterol absorption (campesterol-to-cholesterol and sitosterol-to-cholesterol ratios) significantly increased in the LPV/r-group, but not in the EFV-group, whereas there were no changes in either group of the lathosterol-to-cholesterol ratio, a marker of cholesterol synthesis.

Treatment with an LPV/r-based therapy increased total cholesterol relative to EFV-based therapy. Our data suggest that absorption rather than synthesis is the mechanism involved in LPV/r-associated increased total cholesterol.