Improvements in lipoatrophy, mitochondrial DNA levels and fat apoptosis after replacing stavudine with abacavir or zidovudine

Antiretroviral exposure and lymphocyte mtDNA content among uninfected infants of HIV-1-infected women

OBJECTIVE

Concern for potential adverse effects of antiretroviral (ARV) chemotherapy used to prevent mother-to-child HIV transmission has led the US Public Health Service to recommend long-term follow-up of ARV-exposed children. Nucleoside reverse transcriptase inhibitor ARV agents can inhibit DNA polymerase gamma, impairing mitochondrial DNA (mtDNA) synthesis and resulting in depletion or dysfunction.

METHODS

We measured the mtDNA content of stored peripheral blood mononuclear cells (PBMCs) of 411 healthy children who were born to HIV-uninfected women and 213 uninfected infants who were born to HIV-infected women with or without in utero and neonatal ARV exposure. Cryopreserved PBMC mtDNA was quantified by using the Primagen Retina Mitox assay.

RESULTS

Geometric mean PBMC mtDNA levels were lower at birth in infants who were born to HIV-infected women. Among HIV-exposed children, mtDNA levels were lowest in those who were not exposed to ARVs, higher in those with exposure to zidovudine alone, and higher still in those with combination nucleoside reverse transcriptase inhibitor exposure. A similar pattern was observed in the corresponding women. Levels of mtDNA increased during the first 5 years of life in all HIV-exposed children but achieved normal levels only in those with ARV exposure.

CONCLUSIONS

Levels of mtDNA are lower than normal in HIV-exposed children. Contrary to expectation, PBMC mtDNA levels are significantly higher in ARV-exposed, HIV-uninfected infants and their infected mothers compared with ARV-unexposed infants and women. By 5 years, levels of PBMC mtDNA rise to normal concentrations in ARV-exposed children but remain depressed in ARV-unexposed children.

Mitochondrial DNA depletion and respiratory chain activity in primary human subcutaneous adipocytes treated with nucleoside analogue reverse transcriptase inhibitors

Mitochondrial dysfunction as a consequence of mitochondrial DNA (mtDNA) depletion due to therapy with nucleoside analogue reverse transcriptase inhibitors (NRTI) has been proposed as a pathogenic mechanism leading to lipoatrophy in HIV-infected patients. The aim of our study was to investigate the impact of NRTI treatment on mtDNA abundance and the activities of respiratory chain complexes in primary human subcutaneous preadipocytes (phsPA). We studied adipocyte phenotypes, viability, and differentiation (CCAAT/enhancer-binding protein alpha [C/EBPalpha] and peroxisome proliferator-activated receptor gamma [PPARgamma] expression) and adiponectin production, mtDNA content, mitochondrial membrane potential, mitochondrial mass, and respiratory chain enzyme and citrate synthase activities in both proliferating and differentiating phsPA. Cells were exposed to zidovudine (6 microM), stavudine (d4T; 3 microM), and zalcitabine (ddC; 0.1 microM) for 8 weeks. NRTI-induced mtDNA depletion occurred in proliferating and differentiating phsPA after exposure to therapeutic drug concentrations of d4T and ddC. At these concentrations, ddC and d4T led to an almost 50% decrease in the number of mtDNA copies per cell without major impact on adipocyte differentiation. Despite mtDNA depletion by NRTI, the activities of the respiratory chain complexes, the mitochondrial membrane potential, and the mitochondrial mass were found to be unaffected. Severe NRTI-mediated mtDNA depletion in phsPA is not inevitably associated with impaired respiratory chain activity or altered mitochondrial membrane potential.

Subjective clinical lipoatrophy assessment correlates with DEXA-measured limb fat

OBJECTIVES

Although physician- and patient-rated diagnoses of lipoatrophy are currently used as a basis for inclusion into clinical trials, few studies have compared physician- or patient-rated lipoatrophy severity with objective measures. We aim to assess the validity of physician- and patient-rated diagnoses of lipoatrophy by evaluating the correlation between clinical assessments of lipoatrophy and objective fat indices.

METHODS

This cross-sectional study evaluated the association between clinical lipoatrophy scores and DEXA-measured limb fat (n = 154) and subcutaneous fat mitochondrial DNA (mtDNA) levels (n = 80) in HIV+ individuals.

RESULTS

There was a significant negative correlation between DEXA-measured limb fat and lipoatrophy scores generated by either the patients (r = -0.27, p = .008) or the physician (r = -0.48, p < .0001). Also, a significant positive correlation was found between the patient-generated lipoatrophy score and the physician score (r = 0.68, p < .0001). However, there was no correlation between fat mtDNA levels and DEXA-measured limb fat (r = -0.09, p = .42) or between physician- or patient-generated lipoatrophy scores (r = -0.09, p = .43, and r = 0.04, p = .71, respectively).

CONCLUSION

These results suggest that physician- and patient-rated lipoatrophy scores may be useful surrogates for more expensive measures of lipoatrophy, which could be reserved for research studies.

A longitudinal study of the changes in body fat and metabolic parameters in a South African population of HIV-positive patients receiving an antiretroviral therapeutic regimen containing stavudine

The aim of this study was to determine the patterns of change in body fat and metabolic parameters in a South African cohort on a first line ART regimen containing stavudine. Fasting lipogram, blood glucose and insulin levels, CD4 cell count, viral load, BMI, waist-to-hip ratio (WHR), and skinfold thickness at the triceps, scapula, and iliac crest were measured before starting ART in 42 (27 female) subjects. Repeat measurements were performed at four monthly intervals for 2 years. Lipodystrophy was diagnosed using patient perception and assessment by a physician. At baseline, subjects who went on to develop lipodystrophy (LD group) were fatter and had higher skinfold thickness at all three sites and higher insulin levels than subjects who never developed lipodystrophy (NLD group). The WHR increased to a greater extent while hip circumference and tricep skinfolds fell more significantly in the LD than NLD group. Triglyceride and cholesterol levels increased significantly in both groups while lactate and glucose levels increased more and insulin levels increased less in the LD than the NLD group. Neither viral load nor CD4 count differed between the groups during the study. Viral load correlated positively with insulin levels at baseline. Thus, lipodystrophy in the South African population is characterized by a higher BMI before initiation of ART and lipoatrophy of the arms and hips, lipohypertrophy of the waist, and increased lactate production. When compared to the NLD group, the LD subjects display attenuated insulin secretory output in response to a higher weight gain.

Pharmacogenetics of nucleoside reverse-transcriptase inhibitor-associated peripheral neuropathy

Peripheral neuropathy is an important complication of antiretroviral therapy. Nucleoside reverse-transcriptase inhibitor (NRTI)-associated mitochondrial dysfunction, inflammation and nutritional factors are implicated in its pathogenesis. Pharmacogenetic and genomic studies investigating NRTI neurotoxicity have only recently become possible via the linkage of HIV clinical studies to large DNA repositories. Preliminary case-control studies using these resources suggest that host mitochondrial DNA haplogroup polymorphisms in the hemochromatosis gene and proinflammatory cytokine genes may influence the risk of peripheral neuropathy during antiretroviral therapy. These putative risk factors await confirmation in other HIV-infected populations but they have strong biological plausibility. Work to identify underlying mechanisms for these associations is ongoing. Large-scale studies incorporating clearly defined and validated methods of neuropathy assessment and the use of novel laboratory models of NRTI-associated neuropathy to clarify its pathophysiology are now needed. Such investigations may facilitate the development of more effective strategies to predict, prevent and ameliorate this debilitating treatment toxicity in diverse clinical settings.

Mitochondrial function, morphology and metabolic parameters improve after switching from stavudine to a tenofovir-containing regimen

OBJECTIVES

HIV-associated lipoatrophy has been associated with mitochondrial dysfunction induced by nucleoside reverse transcriptase inhibitor therapy. We hypothesize that lipid profiles and markers of mitochondrial function will improve in HIV-lipoatrophic patients switched to the nucleotide analogue tenofovir.

METHODS

Ten patients receiving stavudine, lamivudine and lopinavir/ritonavir (Kaletra(R)) for over 6 years were switched from stavudine to tenofovir for 48 weeks. Subcutaneous fat tissue biopsies, fasting metabolic tests, HIV RNA, CD4 cell count and whole body dual energy X-ray absorptiometry (DEXA) scans were obtained at study entry and week 48. Mitochondrial DNA (mtDNA) copies/cell and mitochondrial morphology were assessed in adipose tissue biopsies, mtDNA 8-oxo-deoxyguanine in peripheral blood mononuclear cells, and glutathione (GSH) and F2-isoprostane in plasma.

RESULTS

There was no change in limb fat mass by DEXA; however, trunk fat mass increased by 18.9% (P = 0.01). Fasting total cholesterol decreased by 33 mg/dL (P = 0.005) and serum glucose decreased by 4 mg/dL (P = 0.039). mtDNA copies/cell increased from 386 to 1537 (P < 0.001). Transmission electron microscopy showed that mitochondrial cristae were lacking or poorly defined at study entry, whereas mitochondrial inner structures were more well defined and outer membranes were intact at 48 weeks. Oxidative damage decreased in 8/10 patients, GSH increased and F2-isoprostane decreased.

CONCLUSIONS

The results from this study demonstrate that systemic and peripheral fat mitochondria improve in patients switched to tenofovir following long-term exposure to stavudine, while continuing protease inhibitor therapy.

Metabolic syndrome associated with HIV and highly active antiretroviral therapy

The introduction of highly active antiretroviral therapy (HAART) has significantly improved the clinical outcome of HIV disease with increased survival rates. However, some HAART regimens, especially those including protease inhibitors, have been shown to cause in a high proportion of HIV-infected patients metabolic (dyslipidemia, insulin resistance) and somatic (lipodystrophy/lipoatrophy) changes that are associated with an increased risk of cardiovascular disease (coronary artery disease and stroke). The pathogenesis of HAART-associated metabolic syndrome and of its atherogenic profile is complex, and several factors are involved, including direct effects of HAART on lipid metabolism, endothelial and adipocyte cell function, activation of proinflammatory cytokines, and mitochondrial dysfunction. A better understanding of the molecular mechanisms responsible for this syndrome will lead to the discovery of new drugs that will reduce the incidence of lipodystrophy and related metabolic complications in HIV-infected patients facing long-term HAART.

Hepatic histopathology and clinical characteristics associated with antiretroviral therapy in HIV patients without viral hepatitis

BACKGROUND

All available ARV (antiretroviral) agents can cause hepatotoxicity. Many case reports of ARV-induced hepatotoxicity have been described in patients with confounding viral hepatitis. This case series is comprised 23 HIV-positive patients with hepatic enzyme abnormalities but without the evidence of viral hepatitis. The data available for these 23 patients were assessed with an effort to establish any correlation between ARV therapy and abnormal liver function tests (LFTs) as well as the histologic findings on liver biopsies.

METHODS

The 23 participants included in this study were referred to a hepatology/gastrointestinal clinic that catered specifically to HIV patients. The patients were referred by their HIV providers for evaluation of elevated LFTs, gastrointestinal symptoms or cirrhosis. The data surveyed included variables associated with hepatotoxicity and HIV infection.

RESULTS

Liver biopsies were obtained in 21 out of 23 participants. The remaining two participants had evidence of cirrhosis based on imaging studies. The LFT elevations were definitely or possibly attributed to ARV therapy in 17 out of 23 participants. Specifically, the biochemical hepatotoxicity was definitely related to ARV therapy in six and possibly related to ARV medications in 11 participants. Nine out of 17 participants had evidence of nonalcoholic steatohepatitis, whereas four out of 17 had clinical features of lipodystrophy. Six participants had elevated LFTs before starting ARV therapy. The participants with nonalcoholic fatty liver diseases had normal LFTs for many years after which a steep rise was noted. All participants with nonalcoholic fatty liver diseases were exposed to nucleoside reverse transcriptase inhibitors.

CONCLUSION

ARV medications, particularly the nucleoside reverse transcriptase inhibitors, can cause a dose-dependent hepatotoxicity that occurs after several months of exposure and possibly result in increasing the adverse effects of alcohol and obesity. Owing to the overlap of ARV medications, the contribution of each class of drugs toward the observed hepatotoxicity is not entirely clear. Liver biopsies should be considered in patients receiving ARV therapy with elevated LFTs and/or evidence of fatty liver.

Mitochondrial oxidative phosphorylation protein levels in peripheral blood mononuclear cells correlate with levels in subcutaneous adipose tissue within samples differing by HIV and lipoatrophy status

Depletion of mitochondrial DNA (mtDNA) and mtDNA-encoded respiratory chain proteins in subcutaneous (SC) fat from patients with HIV lipoatrophy have clearly demonstrated the role of mitochondrial dysfunction in this syndrome. Research in HIV lipoatrophy, however, has been severely hampered by the lack of a suitable surrogate marker in blood or other easily obtained clinical specimens as fat biopsies are invasive and mtDNA levels in peripheral blood mononuclear cells (PBMC) do not consistently correlate with the disease process. We used a simple, rapid, quantitative 2-site dipstick immunoassay to measure OXPHOS enzymes Complex I (CI) and Complex IV (CIV), and rtPCR to measure mtDNA in 26 matched SC fat and PBMC specimens previously banked from individuals on potent antiretroviral (ARV) therapy with HIV lipoatrophy, on similar ARV therapy without lipoatrophy, and in HIV seronegative controls. Significant correlations were found between the respective PBMC and fat levels for both CI (r = 0.442, p = 0.024) and for CIV (r = 0.507, p = 0.008). Both CI and CIV protein levels were also significantly reduced in both PBMCs and fat in lipoatrophic subjects compared to HIV seronegative controls (p < or = 0.05), while a comparative reduction in mtDNA levels in lipoatrophic subjects was observed only in fat. We conclude that CI and CIV levels in PBMCs correlate to their respective levels in fat and may have utility as surrogate markers of mitochondrial dysfunction in lipoatrophy.

Increased regimen durability in the era of once-daily fixed-dose combination antiretroviral therapy

INTRODUCTION

Data on initial antiretroviral regimen longevity predates the arrival of newer nucleoside reverse transcriptase inhibitor backbones and once-daily regimens. Modern regimens are thought to possess greater tolerability and convenience. We hypothesized this would translate into greater durability.

METHODS

Retrospective study of antiretroviral-naive patients starting treatment at the University of Alabama at Birmingham 1917 HIV/AIDS Clinic 1 January 2000-31 July 2007. Two periods of antiretroviral initiation were identified, prior and after August 2004 (arrival of once-daily fixed-dose regimens). Kaplan-Meier survival analyses of regimen durability by time period and regimen characteristics were performed. Staged Cox proportional hazards models evaluated the roles of dosing complexity and composition in explaining differences in regimen durability between study periods.

RESULTS

Overall 542 patients started antiretroviral drugs (n = 309, January 2000-July 2004; n = 233, August 2004-July 2007). Median durability was 263 days longer in after August 2004 regimens. Regimens started before August 2004 had increased hazards for discontinuation relative to after August 2004 regimens [hazard ratio (HR) = 1.44; 95% confidence interval (CI) = 1.03-2.02]. Time period of initiation lost statistical significance when the model included dosing frequency (HR = 1.92 for at least twice daily vs. daily; 95% CI = 1.29-2.88). As regimen composition variables were added, time period and dosing frequency lost significance. Increased hazards of discontinuation were observed with didanosine or stavudine relative to abacavir or tenofovir use (HR = 1.92; 95% CI = 1.29-2.88) and all third drugs compared with non-nucleoside reverse transcriptase inhibitor-based regimens (triple-nucleoside reverse transcriptase inhibitor HR = 1.76; 95% CI = 1.14-2.73; unboosted-protease inhibitor HR = 1.58; 95% CI = 1.02-2.46; boosted-protease inhibitor HR = 1.57; 95% CI = 1.02-2.41). Affective mental health disorders increased the hazard of discontinuation in all models.

CONCLUSION

Durability of contemporary once-daily fixed-dose antiretroviral regimens has significantly eclipsed the duration of earlier antiretroviral drug options. Our results indicate this is due to both more convenient dosing and improved tolerability of modern antiretroviral regimens.

Genetic polymorphisms differently influencing the emergence of atrophy and fat accumulation in HIV-related lipodystrophy

OBJECTIVE AND DESIGN

The present study aims at evaluating the influence of genetic polymorphisms on antiretroviral therapy (ART)-associated lipodystrophy. We included in the study 255 ICoNA. patients and we assessed the distribution of Fas -670 AG polymorphism, ApoC3 -455 CT and -482 CT polymorphisms, C161T silent substitution in the PPAR gamma gene, the Adrenergic beta3 Receptor (ARbeta3) codon 64 TC variant, and two polymorphisms in the Adrenergic beta2 Receptor (ARbeta2) codon 16 AG and codon 27 CG. Crude rates of lipoatrophy and fat accumulation and adjusted relative rates were calculated using Poisson regression.

RESULTS

In a multivariate model after adjusting for gender, HIV exposure, age, current viral load, hepatitis C virus (HCV) serology, nucleoside reverse-transcriptase inhibitor (NRTI) pair/'third drugs' currently used, months of pre-highly active antiretroviral therapy (HAART) exposures to NRTI, the following genotypes resulted protective against lipoatrophy: ApoC3 -455 CC genotype [adjusted relative risks (ARR) 0.2, 95% confidence interval (CI) 0.046-0.91 vs CT/TT, P = 0.037], ARbeta3 codon 64 TT genotype (ARR 0.39, 95% CI 0.14-1.06 vs TC/CC, P = 0.066), and Fas -670 GG genotype (ARR 0.51, 95% CI 0.26-1.01 vs AG/AA, P = 0.053). With regard to fat accumulation, in the multivariate model, the ARbeta2 codon 27 CC genotype resulted protective (ARR 0.21, 95% CI 0.08-0.51 vs CG/GG, P = 0.0006), whereas the ARbeta2 codon 16 AA genotype resulted associated with higher risk (ARR 3.72, 95% CI 1.58-8.76 vs AG/GG, P = 0.0026).

CONCLUSION

Our study suggests that genetic polymorphisms of genes involved in apoptosis and adipocyte metabolism are significantly related to ART associated lipodystrophy. Particularly, we evidenced a role for ApoC3 -455 in lipoatrophy and for the two variants of ARbeta2 in fat accumulation.

Effect of reducing the dose of stavudine on body composition, bone density, and markers of mitochondrial toxicity in HIV-infected subjects: a randomized, controlled study

BACKGROUND

Stavudine is widely used in developing countries. Lipoatrophy and mitochondrial toxicity have been linked to stavudine use, but it is unclear whether switching to a lower dose can reduce these toxicities while maintaining human immunodeficiency virus (HIV) suppression.

METHODS

HIV-infected subjects receiving standard-dose stavudine with undetectable HIV type 1 RNA for > or =6 months were randomized (ratio, 3:2) to receive one-half of the stavudine dose (switch arm) or to maintain the dose (continuation arm) while continuing to receive all other prescribed antiretrovirals. The following measurements were obtained at baseline and week 48: fasting lactate, pyruvate, and lipid levels; results of whole-body dual-energy x-ray absorptiometry; and mitochondrial DNA (mtDNA) measurements in fat and peripheral blood mononuclear cells. Change from baseline to week 48 was compared within and between groups.

RESULTS

Twenty-four patients (79% of whom were men and 79% of whom were African American; median age, 45 years) were enrolled in the study, 15 were enrolled in the switch arm, and 9 were enrolled in the continuation arm. The median duration of stavudine treatment was 55 months (range, 21-126 months). The median CD4 cell count was 558 cells/mm(3) (range, 207-1698 cells/mm(3)). At baseline, the study arms had similar demographic characteristics and laboratory indices, except for body mass index, total lean body mass, and triglyceride levels (all of which were higher in the switch arm). Three patients (2 in the switch arm) discontinued the study because of study-unrelated reasons. CD4 cell counts remained unchanged. At 48 weeks, 6 patients (4 [27%] in the switch arm and 2 [22%] in the continuation arm) had detectable HIV RNA levels (median, 972 copies/mL; range, 60-49,400 copies/mL). All patients with detectable HIV RNA levels reported significant lapses in treatment adherence; none exhibited mutations in HIV genotype. After the treatment switch, significant changes from study entry to week 48 were noted only for lactate level (median change, -0.27 mmol/L; range, -1.2 to 0.25 mmol/L; P = .02) and fat mtDNA (median change, 40 copies/cell; range, -49 to 261 copies/cell; P = .02). In the continuation arm, a significant loss of bone mineral density was seen at week 48 (median change, -1.7%; range, -6.3% to 0.8%; P = .02). The only significant between-group difference was the change in bone mineral density from baseline (P = .003).

CONCLUSIONS

Reducing stavudine dose by one-half increased fat mtDNA and decreased lactate levels, suggesting improvement in mitochondrial indices while preserving HIV suppression in subjects who maintained adherence. A significant loss of bone mineral density was seen in patients receiving standard-dose stavudine but not in those receiving low-dose stavudine. These results suggest that switching to low-dose stavudine may improve mitochondrial indices while maintaining virological suppression.

Mitochondrial RNA and DNA alterations in HIV lipoatrophy are linked to antiretroviral therapy and not to HIV infection

Background

The aim of this study was to assess the effect of antiretroviral therapy (ART) versus HIV on mitochondria in fat.

Methods

Subcutaneous fat was collected from 45 HIV-infected patients on ART with lipoatrophy, 11 HIV-infected ART-naive patients and nine healthy controls. Three mitochondrial transcripts: NADH dehydrogenase subunit 1 (ND1), cytochrome B (CYTB) and NADH dehydrogenase subunit 6 (ND6) genes were quantitated using TaqMan® probes and normalized to nuclear-encoded ribosomal L13.

Results

ND1/L13 and CYTB/L13 were lower in HIV-positive patients on ART with lipoatrophy versus ART-naive patients (3.4 versus 7.2 [ P=0.017] and 2.5 versus 4.6 [ P=0.006], respectively). No difference was found between ART-naive patients and controls ( P>0.70). ND6/ L13 was similar between all groups. Dual-energy X-ray absorptiometry-measured limb fat and mitochondrial DNA in fat were also lower in HIV-positive patients on ART with lipoatrophy versus HIV-infected, ART-naive patients (4,382 versus 7,662 g [ P=0.02] and 726 versus 1,372 copies/cell [ P=0.03], respectively), but no difference was found between ART-naive and controls. In a multiple regression analysis, limb fat correlated with all three mitochrondrial RNA, whereas mitochondrial DNA did not correlate with mitochondrial RNA or limb fat.

Conclusions

In contrast to ART-naive patients, HIV-positive patients on ART with lipoatrophy had significant depletion in mitochondrial DNA in fat and mitochondrial RNAs. This suggests that mitochondrial toxicity in lipoatrophy could be driven by ART and not by HIV itself. In addition, mitochondrial RNA abnormalities, and not mitochondrial DNA depletion, could be a key driving force behind lipoatrophy.

Safety of stavudine in the treatment of HIV infection with a special focus on resource-limited settings

BACKGROUND

Western randomized trials and prospective cohorts in resource-limited settings have proven virological success with stavudine-based highly active antiretroviral therapy. However, stavudine is no longer recommended in first-line treatments in these two settings due to its intrinsic toxicities and side effects. Yet it remains a cornerstone of treatment in resource-limited settings, due to lack of alternatives and its availability in generic fixed-dose combinations.

OBJECTIVE

To review the toxic effects of stavudine and their prevention and management strategies, especially in resource-limited settings.

METHODS

Data from clinical and pharmacological trials in Western countries, as well as prospective cohorts in resource-limited settings, were reviewed.

CONCLUSION

Initiating or switching to less toxic nucleoside analogues whenever possible, or lowering stavudine doses to 30 mg b.i.d., is strongly recommended.

Mitochondrial DNA content, an inaccurate biomarker of mitochondrial alteration in human immunodeficiency virus-related lipodystrophy

Lipoatrophy is a prevalent side effect of antiretroviral treatment of human immunodeficiency virus (HIV) infection. Its mechanisms are still disputed but include mitochondrial toxicity and, in particular, mitochondrial DNA (mtDNA) depletion induced by nucleoside reverse transcriptase inhibitors. To obtain an integrated evaluation of the mitochondrial alteration in lipoatrophy, we investigated the DNA, RNA, and protein levels in 15 samples of abdominal subcutaneous adipose tissue from HIV-infected patients with peripheral lipoatrophy and compared the results with those for 15 samples from age- and body mass index-matched controls. The DNA and RNA analyses used PCR-based techniques, while proteins were quantified with enzyme-linked immunosorbent assay and measurement of activities with spectrophotometric assays. Depletion of mtDNA and mtDNA-encoded MT-CO2 mRNA was present, but normal levels of mtDNA-dependent activity (cytochrome c oxidase) and protein (MT-CO2p) showed that it was compensated for. An increase in nuclear-DNA-dependent mitochondrial activities (citrate synthase and malate dehydrogenase) and protein (COX4I1p), as well as transcriptional up-regulation of nuclear-DNA-encoded mitochondrial genes (COX4I1 and UCP2), demonstrated increased mitochondrial biogenesis. However, the expression of the known transcription factors of mitochondrial biogenesis (TFAM, NRF1, GABPA, PPARGC1A, PPARGC1B, and PPRC1) was normal or decreased. Increased amounts of activated caspase 3 and of DDIT3 mRNA showed the induction of apoptosis and oxidative stress, respectively. The mtDNA content did not correlate with any other mitochondrial parameter. In conclusion, mtDNA content does not appear to be an accurate biomarker of mitochondrial alteration in lipoatrophic adipose tissue. The preservation of mtDNA-dependent mitochondrial functions occurred despite severe mtDNA depletion. The presence of significant oxidative stress and apoptosis did not correlate with the mtDNA content.

Increased mtDNA levels without change in mitochondrial enzymes in peripheral blood mononuclear cells of infants born to HIV-infected mothers on antiretroviral therapy

BACKGROUND

The effects of gestational nucleoside reverse transcriptase inhibitors (NRTIs) on mitochondrial DNA (mtDNA) are controversial. The effects of mtDNA depletion on mitochondrial function have not been assessed.

METHOD

In peripheral blood mononuclear cells (PBMCs) from infants born to HIV-infected women and infants born to HIV-1-uninfected women, mtDNA copy numbers were determined by quantitative PCR; nuclear (COXIV)- and mitochondrial (COXII)-encoded polypeptides of the oxidative phosphorylation enzyme cytochrome c-oxidase (COX or complex IV) were quantified by Western blot.

RESULTS

Overall, 86 infants born to HIV-infected women and 50 controls were studied. HIV-infected mothers had a median CD4 count of 506 cells/microL; 59% had HIV RNA 50 copies/mL. No infant had clinical evidence of mitochondrial disease. The birth weight was lower (p = .016) and the body length higher (p = .002) in the HIV-exposed newborns. Eighty-one HIV-infected women had received gestational NRTIs (median duration 162 days). Median mtDNA copies/PBMC in the HIV-exposed infants were 505 (range, 120-1365) vs. 213 (27-426) in controls (p < .001). COX II/IV ratios were similar in both groups. Although mtDNA levels correlated inversely with maternal lactate, mitochondrial indices did not correlate with maternal CD4+ count, HIV RNA, smoking, or alcohol consumption.

CONCLUSION

We found elevated mtDNA copy numbers in PBMC of infants born to HIV-infected women, the majority of whom received NRTI-based therapy, when compared to those born to healthy HIV-negative controls, but there was no difference in mtDNA-encoded respiratory chain protein. The clinical consequence of these findings is unknown and requires further investigations.

Pharmacogenetic information derived from analysis of HLA alleles

A large amount of pharmacogenetic information has, in particular, accumulated on the association between human leukocyte antigen (HLA) alleles and hypersensitivity to certain drugs. Prospective HLA typing has dramatically reduced the risk of abacavir hypersensitivity because of its strong association with HLA-B*5701. Significant predisposition to nevirapine hypersensitivity has been reported in Caucasian Australians harboring HLA-DRB1*0101 with high CD4+ T-cell counts, and Sardinians and Japanese harboring HLA-Cw8. A strong association between carbamazepine hypersensitivity and HLA-B*1502 has been reported in Han Chinese. Most Han Chinese individuals with allopurinol-induced severe cutaneous adverse reactions are positive for HLA-B*5801. HLA typing can stratify risk of hypersensitivity to certain drugs and allow personalized treatment, although the patients should be monitored closely even if they are negative for HLA alleles associated with hypersensitivity.

Partial Immunological and Mitochondrial Recovery after Reducing Didanosine doses in Patients on Didanosine and Tenofovir-Based Regimens

Background

Tenofovir disoproxil fumarate (TDF) has a safe toxicity profile; however, administration together with didanosine (ddI) increases ddI levels causing mitochondrial damage and CD4+ T-cell decline. We assessed whether a simple reduction of the ddI dose in patients receiving ddI (400 mg/day) and TDF could revert this side effect.

Methods

Immunological and mitochondrial changes were analysed in 20 patients at baseline, after 14 months of receiving ddI (400 mg/day), TDF (300 mg/day) and nevirapine (NVP; 400 mg/day) and 14 months after a ddl dose reduction to 250 mg/day. Immunological analyses measured CD4+ and CD8+ T-cell counts and mitochondrial studies in peripheral blood mononuclear cells assessed mitochondrial DNA content by quantitative real-time PCR, cytochrome c oxidase (COX) activity by spectrophotometry and mitochondrial protein synthesis (COX-II versus β-actin or COX-IV expression) by western blot.

Results

Treatment with TDF, ddI (400 mg/day) and NVP for 14 months produced significant decreases in mitochondrial parameters and CD4+ T-cell counts. The reduction in ddI dose resulted in mitochondrial DNA recovery; however, the remaining mitochondrial parameters remained significantly decreased. Levels of CD4+ T-cells were partially restored in 35% of patients. Subjects presenting a significant reduction in CD4+ T-cells during the high ddI dose period showed greater mitochondrial impairment in this stage and better mitochondrial and immunological recovery after drug reduction.

Conclusions

Administration of high ddI doses together with TDF was associated with mitochondrial damage, which may explain the observed CD4+ T-cell decay. A reduction of the ddI dose led to mitochondrial DNA recovery, but was not sufficient to recover baseline CD4+ T-cell counts. Other mitochondrial toxicity in addition to DNA γ-polymerase inhibition could be responsible for CD4+ T-cell toxicity.

Effects of the change from Stavudine to tenofovir in human immunodeficiency virus-infected children treated with highly active antiretroviral therapy: studies on mitochondrial toxicity and thymic function

BACKGROUND

Changing from drugs that have significant mitochondrial toxicity to less toxic compounds may be of benefit in human immunodeficiency virus (HIV)-positive patients who receive highly active antiretroviral therapy. Few data on mitochondrial toxicity of antiviral drugs are available in HIV-positive children.

METHODS

Eighteen HIV-positive children (median age, 10.9 years) receiving a stavudine-containing regimen were randomized to maintain stavudine (arm A) or change to tenofovir (arm B), while preserving the remaining drugs. Glucose, lipidic, and viro-immunologic factors were assessed at months 0, 1, 3, 6, 12, and 18. Thymic output and mtDNA content were measured in peripheral blood mononuclear cells at 0 and 6 months, mtDNA in isolated CD4+ and CD8+ T cells after 18 months.

RESULTS

From baseline to month 6, arms A and B showed similar thymic output and mtDNA. After 18 months, a significant decrease in plasma HDL was observed in arm B, along with a small increase in blood glucose; mtDNA showed no difference. In the 2 arms other factors did not show significant differences from the baseline and from the previous values at 18 months.

CONCLUSIONS

Changing from stavudine to tenofovir was well-tolerated, and viro-immunologic success was maintained.

Mitochondrial disorders among infants exposed to HIV and antiretroviral therapy

Although antiretroviral therapy (ART) is critical for preventing mother-to-child transmission of HIV, concern has been raised about the possibility that it may cause mitochondrial dysfunction in infants. There is adequate evidence for a mechanism by which exposure to nucleoside reverse transcriptase inhibitors (NRTIs) could lead to mitochondrial dysfunction; animal studies have shown evidence of mitochondrial dysfunction in the offspring of animals treated with NRTIs and mitochondrial disorders occur in adults treated with NRTIs. This systematic review synthesises the published research on mitochondrial dysfunction and disorders in infants exposed to HIV and antiretrovirals. We found conflicting evidence regarding the possible association of in utero ART exposure with mortality and morbidity due to mitochondrial dysfunction. ART exposure in utero or postpartum was associated with persistent decreases in lymphocytes, neutrophils and platelets as well as an increased risk of transient lactic acidaemia, anaemia and mitochondrial DNA depletion, although these laboratory findings were generally not associated with clinical symptoms. We conclude that large, prospective studies of HIV-exposed infants are needed to resolve the discrepant results regarding morbidity and mortality related to mitochondrial disorders, to ascertain the clinical significance of effects on laboratory values, to determine whether or not the incidence of mitochondrial disorders differs by regimen and to develop predictive models that might identify which infants are at the greatest risk. The challenges that remain to be addressed include the development of a sensitive but affordable screening algorithm in combination with specific diagnostic criteria; consistent collection of data on ART exposure and other risk factors, long-term follow-up of HIV-exposed but uninfected children and implementation in resource-limited settings.

Considering metabolic issues when initiating HIV therapy

Patients with HIV infection and their clinicians are increasingly considering the risk of metabolic complications when choosing HIV therapies. Fear of the potential metabolic consequences of antiretroviral agents may lead some to delay HIV therapy and threaten medication adherence once treatment is initiated. Until recently, there has been limited objective study of the relative contributions of specific antiretrovirals and particular combinations of these drugs to dyslipidemia and body fat changes; in lieu of data, unsupported perceptions regarding the links between therapies and these metabolic complications have predominated. Over the past year, a number of comparative clinical trials have clarified the association between exposure to antiretrovirals and lipid and fat disorders and, in some cases, have yielded results that challenge our perceptions regarding the causes of these complications.

A 6-Month Interruption of Antiretroviral Therapy Improves Adipose Tissue Function in HIV-Infected Patients: The ANRS EP29 Lipostop Study

Objective

To examine the reversibility of adipose tissue alterations in HIV-infected patients after a 6-month interruption of antiretroviral therapy (ART).

Methods

Forty HIV-infected patients on stable effective ART were enrolled, 33 of them completed the study. Patients underwent a physical examination, laboratory tests and needle biopsy of subcutaneous abdominal adipose tissue both at inclusion and at month 6. Changes in fat morphology, mitochondrial DNA (mtDNA) content and gene expression were examined in 29, 23 and 20 patients, respectively.

Results

Body fat distribution was not clearly modified at month 6. Adipose tissue inflammation improved markedly, with fewer infiltrating macrophages and fewer tumour necrosis factor a (TNFα)- and interleukin 6 (IL6)-expressing cells. Expression of peroxisome proliferator-activated receptor γ (PPAR-γ) and of markers of mitochondrial function and biogenesis (cytochrome oxidase 2 and PPAR-γ coreceptor 1α) improved after protease inhibitor (PI) withdrawal. In patients who stopped taking stavudine or zidovudine, the number of TNFα- and IL6-expressing cells was lower at month 6 than at month 0, and so was CD68 expression, a macrophage marker. Adipocyte mitochondrial status also improved, with lower mitochondrial density and cytochrome oxidase 4 mRNA levels, and higher mtDNA content. Sterol regulatory element binding protein 1 mRNA levels increased, reflecting better adipocyte differentiation.

Conclusions

A 6-month ART interruption markedly improved adipose tissue functions, although fat distribution did not visibly change. Stavudine and zidovudine were associated with marked inflammation, which improved when these drugs were withdrawn; they also had a negative effect on differentiation and mitochondrial status. PIs were also associated with altered adipocyte differentiation and mitochondrial status. These data clearly show the detrimental effect of antiretroviral drugs, in particular thymidine analogues, on adipose tissue and argue for switch strategies sparing these drugs.

Substitutions due to antiretroviral toxicity or contraindication in the first 3 years of antiretroviral therapy in a large South African cohort

INTRODUCTION

The patterns and reasons for antiretroviral therapy (ART) drug substitutions are poorly described in resource-limited settings.

METHODS

Time to and reason for drug substitution were recorded in treatment-naive adults receiving ART in two primary care treatment programmes in Cape Town. The cumulative proportion of patients having therapy changed because of toxicity was described for each drug, and associations with these changes were explored in multivariate models.

RESULTS

Analysis included 2,679 individuals followed for a median of 11 months. Median CD4+ T-cell count at baseline was 85 cells/microl. Mean weight was 59 kg, mean age was 32 years and 71% were women. All started non-nucleoside reverse transcriptase inhibitor-based ART (60% on efavrienz) and 75% started on stavudine (d4T). After 3 years, 75% remained in care on-site, of whom 72% remained on their initial regimen. Substitutions due to toxicity of nevirapine (8% by 3 years), efavirenz (2%) and zidovudine (8%) occurred early. Substitutions on d4T occurred in 21% of patients by 3 years, due to symptomatic hyperlactataemia (5%), lipodystrophy (9%) or peripheral neuropathy (6%), and continued to accumulate over time. Those at greatest risk of hyperlactataemia or lipodystrophy were women on ART > or =6 months, weighing > or =75 kg at baseline.

DISCUSSION

A high proportion of adult patients are able to tolerate their initial ART regimen for up to 3 years. In most instances treatment-limiting toxicities occur early, but continue to accumulate over time in patients on d4T. Whilst awaiting other treatment options, the risks of known toxicities could be minimized through early identification of patients at the highest risk.

Impact of nucleoside reverse transcriptase inhibitors on mitochondria in human immunodeficiency virus type 1-infected children receiving highly active antiretroviral therapy

Mitochondrial toxicity induced by nucleoside reverse transcriptase inhibitors (NRTIs) has been reported to be responsible for various adverse effects. The relative impact of NRTIs on the mitochondria of human immunodeficiency virus (HIV) type 1 (HIV-1)-infected children receiving highly active antiretroviral therapy (HAART) is unknown. Mitochondrial DNA (mtDNA) levels were quantified longitudinally from peripheral blood mononuclear cells (PBMCs) in 31 HIV-1-infected children from Pediatric AIDS Clinical Trial Group Study 382 who were receiving HAART, including nelfinavir, efavirenz, and different NRTIs, and who had had undetectable plasma HIV-1 RNA levels for >2 years. The median mtDNA levels in PBMCs increased from 137 copies/cell at the baseline to 179 copies/cell at week 48 (P = 0.01) and 198 copies/cell at week 104 (P < 0.001). Before the initiation of HAART, children who received regimens containing didanosine had mtDNA levels persistently lower than those in children not receiving didanosine (106 versus 140 copies/cell; P = 0.008). During HAART, the median increase in the mtDNA level from the baseline to week 104 was the lowest in children who received regimens containing didanosine (+26 copies/cell) compared to those in children who received other regimens (+79 copies/cell) (P = 0.02). A multivariate analysis also demonstrated that didanosine, as part of HAART, was the only NRTI associated with the change in mtDNA levels (P = 0.007). Children receiving didanosine-containing antiretroviral regimens have the lowest mtDNA levels in PBMCs and may be at greater risk for long-term adverse effects due to mitochondrial toxicity. This may be of particular importance in resource-limited countries where didanosine is widely used for the treatment of HIV-infected children.

Adverse effects of highly active antiretroviral therapy in developing countries

Recent increases in access to highly active antiretroviral therapy (HAART) have made the management of drug toxicities an increasingly crucial component of human immunodeficiency virus (HIV) care in developing countries. The spectrum of adverse effects related to HAART in developing countries may differ from that in developed countries because of the high prevalence of conditions such as anemia, malnutrition, and tuberculosis and frequent initial presentation with advanced HIV disease. The severity of adverse effects may vary as a result of host genetics and diagnostic delays attributable to inadequate laboratory monitoring. This article reviews current knowledge about toxicities related to HAART in resource-limited regions, which are in the process of rapid treatment scale-up. We conclude that initiating HAART before advanced immunosuppression, titrating doses in single-pill drug combinations to differences in patients' body weights, providing more intensive laboratory monitoring during the initial months of therapy, and providing access to less-toxic nucleoside reverse-transcriptase inhibitors may decrease the incidence of toxicities related to HAART in resource-limited regions.

Side effects of HIV therapy

The use of highly active effective antiretroviral therapies (ART) has dramatically decreased the morbidity and mortality of the HIV infection. Over 20 anti-retroviral substances are available in four different classes. Side effects of HIV therapy are common and may influence the prognosis, as the medications are required lifelong for the still incurable infection. ART-associated allergic reactions, lipodystrophy syndrome and immune reconstitution syndrome are side effects frequently seen by dermatologists. Exanthems are challenging as drug reactions must be separated from immune reconstitution, syphilis and viral exanthems and then the causative agent must be identified from a long list of medications. Non-nucleoside reverse transcriptase inhibitors typically cause allergic exanthems. Mitochondrial toxicity caused by nucleoside reverse transcriptase inhibitors is responsible for lipoatrophy and fatty changes in the liver. Protease inhibitors cause diarrhea, abnormalities of glucose and fat metabolism and lipohypertrophy. Before other medications or surgical measures are undertaken to address side effects of ART, the regimen should be adjusted to include alternative but equally effective agents.

Lipodystrophy in HIV 1-infected patients: lessons for obesity research

Lipodystrophy is a common alteration in HIV 1-infected patients under anti-retroviral treatment. This syndrome is usually associated with peripheral lipoatrophy, central adiposity and, in some cases, lipomatosis, as well as systemic insulin resistance and hyperlipidemia. Research on the ethiopathogenesis of the disease revealed novel aspects of adipose tissue biology highly relevant to obesity research: the pivotal role of mitochondria in white adipose tissue function, the role that interference with master transcription factors of adipogenesis may have in human adipose tissue, the capacity of human white adipose tissue to acquire brown fat-like features, as well as the importance of apoptosis and the potential impact of viral infections in adipose tissue. The dramatic difference between subcutaneous adipose depots, prone to lipoatrophy, and the visceral adipose depots, prone to enlargement, has been further evidenced in the study of the lipodystrophy syndrome. The recognition of a local pro-inflammatory environment in lipoatrophic adipose tissue from affected patients, including macrophage infiltration and enhanced expression of chemokines and cytokines, points to events paradoxically similar to those in the hypertrophied adipose tissue in obesity. However, this also potentially provides an explanation for the existence of systemic alterations common to lipodystrophy and obese patients and reminiscent of the metabolic syndrome.

Neuroleptic treatment effect on mitochondrial electron transport chain: peripheral blood mononuclear cells analysis in psychotic patients

A limitation in the use of classic neuroleptic drugs is the eventual appearance of extrapyramidal symptoms. Some studies, mainly based on experimental situations, have related these symptoms with a defect in the mitochondrial electron transport chain (ETC), especially with complex I (CI). One of the advantages of the "atypical" neuroleptics is a lower incidence of movement disorders. We studied peripheral blood mononuclear cells from naive schizophrenic patients (n = 25) and patients under chronic treatment with 1 "typical" neuroleptic (haloperidol, n = 15) or 1 "atypical" neuroleptic (risperidone, n = 23; or clozapine, n = 21). Patients were on standard clinical situation, on treatment for at least 28 months, and did not present signs or symptoms of extrapyramidal dysfunction. Absolute enzyme activities of ETC complexes I to IV were spectrophotometrically quantified, and oxygen consumption with substrates of different complexes was measured polarographically. As an indirect measure of oxidative damage, we quantified membrane lipid peroxidation through the loss of cis-parinaric acid fluorescence. We found differences among groups when comparing the activity of CI, which was decreased in patients receiving neuroleptics, either assessed enzymatically or through oxygen consumption. This effect was lower for atypical neuroleptics than for haloperidol. Haloperidol was also associated with a significant increase of peripheral blood mononuclear cell membrane peroxidation. We conclude that antipsychotics given at clinical standard doses, either typical or atypical, inhibit CI of the ETC. It remains to be established if this finding in a nontarget tissue for antipsychotics may account for the lower incidence of movement disorders observed in patients on atypical agents.

Dysregulated Energy Expenditure in HIV-Infected Patients: A Mechanistic Review

Metabolic abnormalities are common in patients with human immunodeficiency virus (HIV) infection and range from protein catabolism to lipodystrophy and dyslipidemia associated with the use of highly active antiretroviral therapy. One abnormality is increased resting energy expenditure, which even occurs in clinically stable HIV-infected patients. Increased resting energy expenditure may aggravate the tendency towards weight loss and wasting, which are independent predictors of mortality. Despite much investigation, the factors associated with altered resting energy expenditure remain unclear; viral load, CD4 cell count, use of antiretroviral drugs, body composition, hormones, and proinflammatory cytokines have been imputed. Mechanisms that could explain increased resting energy expenditure include the HIV accessory protein viral protein R, antiretroviral drugs that affect mitochondrial function, and futile cycling within adipocytes. Other components of energy expenditure are also important to overall energy balance and may also be affected. Identifying unifying mechanisms will be an important step to finding effective treatments for HIV-related alterations in energy expenditure and to reversing metabolic risks in patients with HIV infection.

Uridine supplementation in HIV lipoatrophy: pilot trial on safety and effect on mitochondrial indices

OBJECTIVES

Uridine abrogates mitochondrial toxicities of nucleoside reverse transcriptase inhibitor in adipocyte cell culture. We aim to study the effect of uridine supplementation on human adipocyte mitochondrial DNA (mtDNA) levels in subjects with human immunodeficiency (HIV) lipoatrophy.

METHODS

Sixteen patients with lipoatrophy on stavudine-containing antiretroviral therapy were enrolled, and received NucleomaxX, a dietary supplement with a high bioavailability of uridine (36 g TID every other day for 16 weeks). Patients were then followed off-uridine for another 16 weeks. Highly active antiretroviral therapy remained unchanged during the trial.

RESULTS

Fourteen patients completed the study. Two subjects dropped out before week 4 for study-unrelated reasons. No adverse events were noted throughout the study. HIV-1 RNA, CD4 counts, liver enzymes and hemoglobin remained unchanged. Body mass index, lactate, lipids, insulin and homeostasis model assessment of insulin resistance were unaltered. Fat and peripheral blood and mononuclear cell mtDNA levels did not correlate with each other and exhibited no changes throughout the study. Lipoatrophy scores by patients and physician improved significantly at weeks 16 and 32 compared to study entry.

CONCLUSION

In this pilot study, NucleomaxX was safe, well tolerated without apparent deleterious effect on HIV indices. In contrast to in vitro data, NucleomaxX did not lead to changes in fat or blood mtDNA levels.

Effects of potent antiretroviral therapy on free testosterone levels and fat-free mass in men in a prospective, randomized trial: A5005s, a substudy of AIDS Clinical Trials Group Study 384

BACKGROUND

Low testosterone levels are commonly reported in patients with advanced human immunodeficiency virus disease. The effects of initiation of different antiretroviral regimens on testosterone levels and changes in fat-free mass have not been reported.

METHODS

Antiretroviral-naive men (n=213) were randomized to receive nelfinavir, efavirenz, or both plus either zidovudine and lamivudine or stavudine and didanosine. Patients underwent measurements of metabolic parameters, including determination of free testosterone level by equilibrium dialysis and bioelectrical impedance analysis, over a 64-week period.

RESULTS

At baseline, the median free testosterone level was 92 pg/mL; the level was subnormal (i.e., <50 pg/mL) in 6%. Lower CD4 cell count at the time of study entry, higher weight, and greater age were independently associated with lower baseline free testosterone level. At week 64, the median free testosterone level increased more in zidovudine-lamivudine recipients (48 of whom had paired values available; change, +31 pg/mL) than in stavudine-didanosine recipients (57 of whom had paired values; change, +3 pg/mL; P=.001, by Wilcoxon rank sum test), and it increased more in efavirenz recipients (37 of whom had paired values; change, +30 pg/mL) than in nelfinavir recipients (28 of whom had paired values; change, -3 pg/mL; P=.05). The median fat-free mass for the entire group increased by 1.2 kg at week 64 (change, +2.0%; P<.001); the increase was greater in the zidovudine-lamivudine group (n=70; change, +1.8 kg) than in the stavudine-didanosine group (n=79; change, +0.5 kg; P=.04), and the increase was also greater for efavirenz recipients (n=53; change, +2.1 kg) than among nelfinavir recipients (n=47; change, +0.4 kg; P=.003). White race, lower CD4 cell count at study entry, assignment to the efavirenz treatment arm, and assignment to the zidovudine-lamivudine treatment arm independently predicted greater absolute change in fat-free mass at week 64.

CONCLUSIONS

Subnormal free testosterone levels occurred infrequently among these antiretroviral-naive men. Free testosterone and fat-free mass levels increased after initiation of antiretroviral therapy, with greater increases at 64 weeks among zidovudine-lamivudine recipients than among stavudine-didanosine recipients and among efavirenz recipients than among nelfinavir recipients.

Exploratory study comparing the metabolic toxicities of a lopinavir/ritonavir plus saquinavir dual protease inhibitor regimen versus a lopinavir/ritonavir plus zidovudine/lamivudine nucleoside regimen

OBJECTIVES

To assess the safety, efficacy and metabolic toxicity of lopinavir/ritonavir + saquinavir or zidovudine/lamivudine and evaluate the pharmacokinetics of lopinavir/ritonavir + saquinavir.

METHODS

HIV-1-infected, antiretroviral-naive subjects were randomized to lopinavir/ritonavir (400/100 mg) twice daily + saquinavir (800 mg) or zidovudine/lamivudine (150/300 mg) in a Phase II, 48 week study. Subjects receiving lopinavir/ritonavir + zidovudine/lamivudine initiated escalating doses of saquinavir (400, 600 and 800 mg) weekly for 3 weeks.

RESULTS

By intent-to-treat (non-completer = failure) analysis, 10/16 (63%) lopinavir/ritonavir + saquinavir-treated and 7/14 (50%) lopinavir/ritonavir + zidovudine/lamivudine-treated subjects achieved plasma HIV-1 RNA <50 copies/mL (P=0.713) at week 48. Safety, tolerability, metabolic changes and truncal fat increases were similar between groups. Small decreases in the lower extremity fat in the zidovudine/lamivudine group (-6%) and a statistically significant increase in the lower extremity fat in the saquinavir group (+19%) were observed. Lopinavir/ritonavir co-administered with saquinavir 600 or 800 mg twice daily produced saquinavir concentrations similar to those previously reported for saquinavir/ritonavir 1000/100 mg twice daily.

CONCLUSIONS

Treatment regimens had similar efficacy and tolerability. Metabolic parameters suggested lipoatrophy in the zidovudine/lamivudine treatment group. Saquinavir 600 and 800 mg twice daily produced concentrations similar to those previously reported for saquinavir/ritonavir 1000/100 mg twice daily.

Relationship of Mitochondrial DNA Depletion and Respiratory Chain Activity in Preadipocytes treated with Nucleoside Reverse Transcriptase Inhibitors

Objective

To study the impact of adipocyte differentiation on nucleoside reverse transcriptase inhibitor (NRTI)-mediated mitochondrial DNA (mtDNA) depletion and to correlate mtDNA depletion with the activity of the respiratory chain complexes.

Methods

We studied adipocyte phenotype, viability, differentiation (CCAAT/enhancer-binding protein [C/EBP]-α and peroxisome proliferator-activated receptor [PPAR]-γ expression), adiponectin production, mtDNA content, activity of respiratory chain complexes and citrate synthase activity in 3T3–L1 adipocytes. Cells were exposed to zidovudine (6 μM or 180 μM), stavudine (3 μM or 90 μM), and zalcitabine (0.1 μM or 3 μM) at different developmental stages for up to 2 months.

Results

Zidovudine and stavudine impaired adiponectin production in vitro at therapeutic Cmax concentrations, but none of the tested NRTIs had a negative impact on adipocyte differentiation or led to mtDNA depletion at these concentrations. Susceptibility of preadipocytes to mtDNA depletion was dependent on cell proliferation and differentiation, and mtDNA depletion occurred only after exposure to high drug concentrations. Under these conditions, stavudine led to up to 80% mtDNA depletion in both dividing and differentiating preadipocytes, whereas zidovudine affected mtDNA only in the differentiating cells. Despite mtDNA depletion by NRTIs, activity of the respiratory chain complexes was found to be unimpaired.

Conclusions

We found mtDNA depletion in adipocytes but proliferation and/or differentiation of the cells seems to be a prerequisite for this phenomenon. Depletion of mtDNA up to 80%, however, was not associated with impaired respiratory chain activity in 3T3-L1 preadipocytes.

Effects of metformin and rosiglitazone in HIV-infected patients with hyperinsulinemia and elevated waist/hip ratio

OBJECTIVE

To evaluate the effects of metformin and rosiglitazone, alone or in combination, on fat distribution, insulin sensitivity, and lipids in HIV-infected patients with insulin resistance and changes in fat distribution.

METHODS

A total of 105 subjects were randomly assigned to receive metformin (500 mg twice a day increasing to 1000 mg twice a day after 2 weeks) with rosiglitazone placebo (Met/P, N = 26); rosiglitazone (4 mg/day) with metformin placebo (Rosi/P, N = 27); rosiglitazone (4 mg/day) plus metformin (500 mg twice a day increasing to 1000 mg twice a day after 2 weeks; Met/Rosi, N = 25); or dual placebo (P/P, N = 27) for 16 weeks. Efficacy assessments included oral glucose tolerance testing, abdominal computed tomography, whole-body dual-energy X-ray absorptiometry, and the measurement of fasting lipids and other biochemical indices. Safety was monitored throughout. Intent-to-treat analyses were performed using non-parametric methods.

RESULTS

The median insulin area under the curve (AUC) decreased significantly compared with baseline in both groups randomly assigned to rosiglitazone (Rosi/P -25.7 microIU/ml, P = 0.012; Met/Rosi -17.7 microIU/ml, P = 0.002); and tended to decrease in the Met/P group (-11.1 microIU/ml, P = 0.058). The change in AUC with combination therapy was significant compared with placebo (P = 0.032). No treatment was associated with significant changes in visceral or subcutaneous abdominal fat. Leg fat increased in subjects on Rosi/P compared with placebo (+4.8 versus -8.3%, P = 0.034). Rosiglitazone, but not metformin, increased adiponectin but also increased LDL-cholesterol and decreased HDL-cholesterol. Gastrointestinal effects occurred frequently in subjects on metformin.

CONCLUSION

Both treatments improved insulin sensitivity, but neither reduced visceral fat. Rosiglitazone may increase subcutaneous fat in some individuals.

Changes in the peripheral blood mtDNA levels in naive patients treated by different nucleoside reverse transcriptase inhibitor combinations and their association with subsequent lipodystrophy

Nucleoside reverse transcriptase inhibitors (NRTIs) differ in the type and severity of adverse effects resulting from mitochondrial abnormalities. mtDNA in peripheral blood mononuclear cells (PBMCs) was measured during the first 12 months of different NRTIs combinations and its association with clinical lipodystrophy was estimated. Extended follow-up of a randomized trial, ALBI-ANRS 070, including antiretroviral naive patients was conducted. Total DNA was extracted from available cryopreserved PBMCs at baseline and months 6 and 12. Nuclear and mitochondrial genes were amplified using a real-time PCR assay. Clinical lipodystrophy was assessed 30 months after randomization using a standardized questionnaire. A logistic regression analysis assessed the value of mtDNA to predict lipodystrophy. Mean mtDNA level (copies/cell) significantly decreased from 5847 at baseline to 3176 at month 12 (p < 0.0001). In the zidovudine + lamivudine (ZDV + 3TC) arm (n = 37), the mean mtDNA was 6098, 6807, and 3725 copies/cell for baseline, month 6, and month 12, respectively. In the stavudine + didanosine (d4T + ddI) arm (n = 40), the mean values were 5616, 5731, and 2648 copies/cell, respectively. The proportion of patients in the lowest quartile of mtDNA (<1421 copies/cell) at month 12 was higher in 18 patients with lipodystrophy (44%) than in 28 without lipodystrophy (7%) (p = 0.008). At 12 months, a larger reduction of mtDNA from baseline was observed in those started on the d4T + ddI arm. Furthermore, a low mtDNA level at month 12 was associated with the subsequent development of lipodystrophy. This marker may be of value for the early prevention of lipodystrophy in treated HIV-infected patients.

Dermatologic adverse effects of antiretroviral therapy: recognition and management

Despite the decrease in opportunistic infections associated with HIV in the highly active antiretroviral treatment (HAART) era, a significant number of patients still present with skin pathology, some of which can be attributed directly or indirectly to antiretroviral therapy. The non-nucleoside reverse transcriptase inhibitors exhibit a class effect with regard to skin adverse manifestations, and the spectrum of disease can vary from a mild morbilliform rash to Stevens-Johnson syndrome. Certain protease inhibitors are associated with rash, and indinavir causes retinoid-like manifestations such as paronychia, alopecia, ingrown toe-nails, and curling of straight hair. Abacavir, a nucleoside reverse transcriptase inhibitor, is notorious for causing a hypersensitivity reaction in select patients. The fusion inhibitor enfuvirtide causes injection-site reactions in the overwhelming majority of patients, although a new method of delivery has decreased the rate and severity of these reactions. A syndrome of lipoatrophy with or without lipohypertrophy, often termed lipodystrophy, has been described in patients receiving HAART. Potential management of lipoatrophy includes switching antiretrovirals and surgical treatment with facial fillers. Lastly, skin manifestations of the immune reconstitution inflammatory syndrome, including herpes zoster and warts, must be recognized and treated accordingly. In the evaluation of the individual HIV-infected patient receiving antiretroviral therapy who presents with a skin disorder, clinicians should consider the CD4 cell count as a marker of the degree of immunodeficiency, the specific antiretrovirals used, and the timing of the initiation of antiretroviral therapy in order to formulate a rational differential diagnosis. Management should be individualized based on the specific drug that is implicated and the severity of the reaction.

Management of antiretroviral drug toxicity

PURPOSE OF REVIEW

With the emergence of very potent antiretroviral regimens, the major limitation to the success of treatment is now the tolerability of drugs, which can ultimately affect adherence. It is important, therefore, to review the current understanding on antiretroviral drug toxicity, and examine key recent data that can inform the successful avoidance or management of such toxicities.

RECENT FINDINGS

A common theme of recent research has focussed on the genetic predisposition to important immediate side-effects, such as abacavir hypersensitivity, nevirapine hepatotoxicity, efavirenz neurotoxicity and hyperbilirubinemia with atazanavir. Long-term toxicities such as body-composition changes and hyperlipidemia have been more closely linked to thymidine analogues and certain protease inhibitors. The management of these toxicities has also been clarified by studies addressing switching antiretroviral drugs or specific treatments for metabolic syndromes.

SUMMARY

Recent data emphasize the need for the prevention of antiretroviral toxicity by the avoidance of some drugs in certain genetically predisposed populations or by the avoidance of entire classes if possible. In addition, recent studies emphasize the importance of ongoing research to determine the emergence of additional toxicities, as new drugs emerge and achieve widespread use.

Metabolic and Mitochondrial Effects of Switching Antiretroviral-Experienced Patients to Enfuvirtide, Tenofovir and Saquinavir/Ritonavir

Objective

Investigate the metabolic and mitochondrial effects of switching a highly active antiretroviral therapy (HAART) regimen with a high mitochondrial toxicity profile to a HAART with a theoretically low mitochondrial toxicity.

Patients and Methods

Six consecutive HAART-experienced patients receiving at least one dideoxy-nucleoside reverse transcriptase inhibitor (NRTI) switched to enfuvirtide plus tenofovir plus saquinavir/ritonavir (T20+TDF+SQV/r). Blood samples were collected at baseline, 12 and 24 weeks after the switch, and viral load (VL) and lymphocyte CD4+ T-cell count were determined. Metabolic parameters consisted of fasting serum triglycerides, cholesterol (total and fractions), glucose, insulin, C-peptide and lactate. Mitochondrial assessment consisted on mitochondrial DNA (mtDNA) quantification, COX-II mitochondrial protein expression rate, mitochondrial respiratory chain complex III and IV activities, and oxygen consumption in peripheral blood mononuclear cells. For baseline mitochondrial comparisons, we included six HIV-infected patients naive for ART.

Results

Switched patients exhibited a mean increase of 26 CD4+ T-cells/mm3 and a mean decrease of 1.1 log in VL ( P=NS for both). Lactate, lipids and glycaemia remained stable during the study; only insulin levels increased significantly ( P<0.05). Switched patients exhibited, at baseline, low mitochondrial measurements, being significant only for complex III and IV activities with respect to naive patients ( P<0.05 for both). MtDNA content did not rise significantly during the study. However, we observed increases in COX-II mitochondrial protein synthesis (124%, P<0.05), complex III activity (127%, P<0.05), complex IV activity (86%, P=0.37) and oxygen consumption (194%, P<0.05).

Conclusion

Switching a HAART-containing dideoxy-NRTI to T20+TDF+SQV/r minimally alters metabolic parameters and exerts beneficial effects on mitochondrial function at 24 weeks. Mitochondrial improvement should be considered as an additional advantage of this rescue therapy.

Highly Active Antiretroviral Therapy-Associated Metabolic Syndrome and Cardiovascular Risk

The introduction of highly active antiretroviral therapy (HAART) has significantly modified the course of human immunodeficiency virus (HIV) disease, with longer survival and improved quality of life of HIV-infected subjects. However, HAART regimens, especially those including protease inhibitors, have been shown to cause in a high proportion of HIV-infected patients a metabolic syndrome (lipodystrophy/lipoatrophy, dyslipidemia, type 2 diabetes mellitus, insulin resistance) that may be associated with an increased risk of cardiovascular disease (coronary artery disease and stroke). A careful stratification of the cardiovascular risk and cardiovascular monitoring of patients under HAART is needed according to the most recent clinical guidelines.

Real-Time Nucleic Acid Sequence–Based Amplification Assay to Quantify Changes in Mitochondrial DNA Concentrations in Cell Cultures and Blood Cells from HIV-Infected Patients Receiving Antiviral Therapy

Background: To study the clinical relevance of changes in mitochondrial DNA (mtDNA) in peripheral blood mononuclear cells (PBMCs) attributable to HIV infection and/or combination antiretroviral therapy (cART), a high-throughput molecular assay to quantify mtDNA is required.

Methods: We developed a quantitative real-time duplex nucleic acid sequence–based amplification assay in which both mtDNA and nuclear DNA are simultaneously amplified in 1 tube. The assay could accurately quantify mtDNA in a range of 15–1500 copies of mtDNA per 2 genomic copies with an intrarun variation of 11% and an interrun variation of 16%. We compared this real-time assay with the lactate/pyruvate ratios in fibroblasts incubated with glucose and exposed to zalcitabine. Additionally, we studied the effects of platelet contamination and the in vivo effects of cART on mtDNA in PBMCs from a small group of patients.

Results: Decreases in mtDNA preceded the increase in lactate/pyruvate ratios and vice versa when zalcitabine was eliminated from the culture. Platelets affected the mtDNA in PBMCs if &gt;5 platelets per PBMC were present. Within 12 weeks, mtDNA increased and remained increased in PBMCs from patients on continuous treatment with zidovudine/lamivudine/indinavir therapy (P = 0.03), but increased if patients were switched to stavudine/didanosine therapy (P = 0.008).

Conclusion: After drug exposure, the mtDNA assay can detect changes in mtDNA concentrations in cell lines and PBMCs, when properly controlled for platelet effects, earlier than traditional assays.