Mild improvement in mitochondrial function after a 3-year antiretroviral treatment interruption despite persistent impairment of mitochondrial DNA content.

OBJECTIVE: The ability of a prolonged antiretroviral treatment interruption to reverse mitochondrial toxicity was evaluated in a sub-study of TIBET, a prospective trial examining antiretroviral treatment interruption guided by CD4+ cell count. PATIENTS AND METHODS: The study population was composed of patients from the TIBET study who had been followed for > or =96 weeks and whose peripheral blood mononuclear cells (PBMCs) had been collected at baseline and throughout the study period. Of the 201 patients included in the TIBET study, 38 were selected for the mitochondrial sub-study; 18 patients discontinued antiretroviral therapy for > or =96 weeks and 20 maintained therapy. Mitochondrial DNA (mtDNA) and RNA (mtRNA) were measured in PBMCs using real-time polymerase chain reaction, and mitochondrial function relative to mitochondrial content was assessed using the cytochrome c oxidase and citrate synthase ratio (COX/CS). RESULTS: Whereas mtDNA content showed a similar progressive decrease throughout the study period in both arms, the mtRNA amount remained stable in both groups and the COX/CS ratio improved significantly in patients who interrupted therapy CONCLUSIONS: Mitochondrial function improved during a prolonged antiretroviral treatment interruption despite a decrease in mtDNA levels in PBMCs, probably because of the existence of a mitochondrial transcriptional and translational upregulation mechanism or the reversion of mitochondrial toxicity by a mechanism that is independent of DNA polymerase gamma. The reduction in virus-related mitochondrial damage should be considered another relevant benefit of antiretroviral therapy.

Improvement of mitochondrial toxicity in patients receiving a nucleoside reverse-transcriptase inhibitor-sparing strategy: results from the Multicenter Study with Nevirapine and Kaletra (MULTINEKA).

BACKGROUND: Nucleoside reverse-transcriptase inhibitor (NRTI)-related mitochondrial toxicity has been suggested as a key factor in the induction of antiretroviral-related lipoatrophy. This study aimed to evaluate in vivo the effects of NRTI withdrawal on mitochondrial parameters and body fat distribution. METHODS: A multicenter, prospective, randomized trial assessed the efficacy and tolerability of switching to lopinavir-ritonavir plus nevirapine (nevirapine group; n = 34), compared with lopinavir-ritonavir plus 2 NRTIs (control group; n = 33) in a group of human immunodeficiency virus-infected adults with virological suppression. A subset of 35 individuals (20 from the nevirapine group and 15 from the control group) were evaluated for changes in the mitochondrial DNA (mtDNA) to nuclear DNA ratio and cytochrome c oxidase (COX) activity after NRTI withdrawal. Dual-energy X-ray absorptiometry (DEXA) scans were used to objectively quantify fat redistribution over time. RESULTS: The nevirapine group experienced a progressive increase in mtDNA content (a 40% increase at week 48; P = .039 for comparison between groups) and in the COX activity (26% and 32% at weeks 24 and 48, respectively; P = .01 and P = .09 for comparison between groups, respectively). There were no statistically significant between-group differences in DEXA scans at week 48, although a higher fat increase in extremities was observed in the nevirapine group. No virologic failures occurred in either treatment arm. CONCLUSIONS: Switching to a nucleoside-sparing regimen of nevirapine and lopinavir-ritonavir maintained full antiviral efficacy and led to an improvement in mitochondrial parameters, which suggests a reversion of nucleoside-associated mitochondrial toxicity. Although DEXA scans performed during the study only revealed slight changes in fat redistribution, a longer follow-up period may show a positive correlation between reduced mitochondrial toxicity and a clinical improvement of lipodystrophy.