Lipodystrophy in patients with HIV-1 infection: effect of stopping protease inhibitors on TNF-alpha and TNF-receptor levels, and on metabolic parameters.

OBJECTIVE: To evaluate the effects of stopping treatment with protease inhibitors (PIs) on tumour necrosis factor (TNF)-alpha and TNF-receptor levels, and on the metabolic and morphological abnormalities seen in patients with lipodystrophy. DESIGN: Longitudinal study. METHODS: Ten HIV-positive patients with lipodystrophy (LD) were studied whilst on PIs (LD1) and 3 months after stopping PIs (LD2) together with 10 HIV-positive subjects on PIs without LD (controls). TNF-alpha and TNF-receptor levels, insulin resistance parameters, lipid and hormonal profiles, body composition and fat distribution were measured in all subjects. RESULTS: TNF-alpha, TNF-receptor I (-RI) and TNF-RII levels were significantly lower in controls (P=0.02) than in subjects with LD, and there was a significant decrease in TNF-RI and TNF-RII levels (P=0.01 and 0.03, respectively) on stopping PIs. Insulin levels and the homeostasis model assessment for insulin resistance (HOMA-IR) index were significantly higher in LD1 subjects (P=0.02) than in controls but did not alter when PIs were stopped. Bioelectrical impedance analysis showed a significant decrease on stopping PIs but CT scans showed no significant difference in fat distribution. Apart from high-density lipoprotein, there was no change in lipid parameters on stopping PIs. There was no difference in the level of testosterone, sex hormone binding globulin and cortisol between the three groups. CONCLUSION: Our results show that TNF-alpha activity in patients with LD is modulated by PIs. This was not accompanied by significant changes in body habitus or insulin resistance, although this may have been a consequence of the short follow-up in this study.

Intracellular accumulation of human immunodeficiency virus protease inhibitors.

Intracellular accumulation of the protease inhibitors (PIs) saquinavir (SQV), ritonavir (RTV), and indinavir (IDV) was determined in 50 human immunodeficiency virus-positive patients. Following extraction, PIs were quantified by mass spectrometry. Paired plasma and intracellular samples were collected over a full dosing interval from patients (13 on SQV, 6 on RTV, 8 on IDV, 16 on SQV plus RTV, 7 on IDV plus RTV) with a plasma viral load of <400 copies/ml. Data were expressed as intracellular/plasma drug concentration ratios. A hierarchy of intracellular accumulation was demonstrated by the following medians: 9.45 for SQV > 1.00 for RTV > 0.51 for IDV. Coadministration of RTV did not boost ratios of SQV or IDV within the cell or in plasma, although absolute plasma and intracellular SQV concentrations were increased by RTV. Seven individuals receiving SQV in hard-gel capsule form (median, 32 months) had higher intracellular/plasma drug ratios than all other patients receiving SQV (median, 17.62 versus 4.83; P = 0.04), despite consistently low plasma SQV concentrations. How this occurs may provide insight into the mechanisms that limit adequate drug penetration into sanctuary sites.