No longitudinal mitochondrial DNA sequence changes in HIV-infected individuals with and without lipoatrophy

Mitochondrial DNA mutations accumulated in HIV-1-infected children who have an excellent virological response when exposed to long-term antiretroviral therapy

Objectives

There is growing concern about mitochondrial DNA (mtDNA) mutations with long-term NRTI exposure in HIV-1 infected children.

Methods

Twenty-four HIV-1 infected children who started ART more than 2 years earlier who had an excellent virological response and had not changed their regimen were enrolled retrospectively. Their corresponding PBMCs in 2009 (T1), 2010 (T2) and 2013 (T3) were included. Sequencing of the entire mtDNA using next-generation sequencing revealed the spectrum of mtDNA variants.

Results

The trend showed that the number of mtDNA mutations during ART occurred as T1 < T2 < T3 (P = 0.086). Interestingly, the numbers of whole mtDNA mutations at T3 (median 41, range 24-62) were significantly greater than at T1 (34, 25-46, P = 0.029). A positive correlation was found between total mtDNA mutations and treatment time (r = 0.352, P = 0.002). During the observation period, mtDNA mutations more frequently occurred in the D-loop, cytochrome b (CYTB) and 12S rRNA regions. The heteroplasmic ratio of T3 was higher than that of T1 in CYTB and 12S rRNA (P = 0.034 and P = 0.042, respectively). High heteroplasmic population levels were found at nt 263 (A263G, D-loop) and nt 8860 (A8860G, ATPase6). A significant difference in heteroplasmy between T1, T2 and T3 occurred at nt 14783 (T14783C, CYTB, P = 0.048, T3 > T2 > T1).

Conclusions

Our findings reveal the spectrum of mtDNA variants in HIV-1-infected children who had an excellent virological response. mtDNA mutations accumulated during ART may play an important role in facilitating the occurrence of mitochondrial dysfunction.

Precision medicine for HIV: where are we?

To date, antiretroviral therapy is highly effective in HIV-affected patients, but the individualization of such a life-long therapy may be advised. This review briefly summarizes the main factors involved in the potential personalization of antiretroviral treatment. Relevant articles in English were identified by PubMed and recent congresses’ abstracts. Foremost influences concerning pharmacodynamics, therapeutic drug monitoring, pharmacogenetics, comorbidities, immune recovery and viral characteristics affecting the healthcare of HIV-positive patients are listed here. Furthermore, pharmacoeconomic aspects are mentioned. Applying pharmacokinetic and pharmacogenetic knowledge may be informative and guide the better choice of treatment in order to achieve long-term efficacy and avoid adverse events. Randomized investigations of the clinical relevance of tailored antiretroviral regimens are needed in order to obtain a better management of HIV/AIDS-affected patients.

Mitochondrial DNA mutations in blood samples from HIV-1-infected children undergoing long-term antiretroviral therapy

We have analyzed mutations in whole mitochondrial (mt) genomes of blood samples from HIV-1-infected children treated with long-term antiretroviral therapy (ART), who had an excellent virological response. HIV-1-infected children who have undergone ART for 4 y with an excellent virological response (group A; 15 children) and ten healthy children (controls) without HIV-1 infection were enrolled retrospectively. Peripheral blood mononuclear cells (PBMCs) were obtained and mt DNA mutations were studied. The total number of mtDNA mutations in group A was 3 H more than in the controls (59 vs. 19, P<0.001) and the same trend was seen in all mtDNA regions. Among these mtDNA mutations, 140 and 28 mutations were detected in group A and the controls, respectively. The D-loop, CYTB and 12s rRNA were the three most common mutation regions in both groups, with significant differences between the groups observed at nucleotide positions C309CC, T489C CA514deletion, T16249C and G16474GG (D-loop); T14783C, G15043A, G15301A, and A15662G (CYTB); and G709A (12s rRNA). G15043A and A15662G had been associated with mitochondrial diseases. Our findings suggest that mtDNA mutations occur frequently in long-term ART-treated, HIV-1-infected children who have an excellent virological response, although they did not have obvious current symptoms. The CYTB region may play an important role in mtDNA mutation during ART, which might contribute to the development of subsequent mitochondrial diseases.

Perspectives on pharmacogenomics of antiretroviral medications and HIV-associated comorbidities

PURPOSE OF REVIEW

To summarize current knowledge and provide perspective on relationships between human genetic variants, antiretroviral medications, and aging-related complications of HIV-1 infection.

RECENT FINDINGS

Human genetic variants have been convincingly associated with interindividual variability in antiretroviral toxicities, drug disposition, and aging-associated complications in HIV-1 infection. Screening for HLA-B5701 to avoid abacavir hypersensitivity reactions has become a routine part of clinical care, and has markedly improved drug safety. There are well established pharmacogenetic associations with other agents (efavirenz, nevirapine, atazanavir, dolutegravir, and others), but this knowledge has yet to have substantial impact on HIV-1 clinical care. As metabolic complications including diabetes mellitus, dyslipidemia, osteoporosis, and cardiovascular disease are becoming an increasing concern among individuals who are aging with well controlled HIV-1 infection, human genetic variants that predispose to these complications also become more relevant in this population.

SUMMARY

Pharmacogenetic knowledge has already had considerable impact on antiretroviral prescribing. With continued advances in the field of human genomics, the impact of pharmacogenomics on HIV-1 clinical care and research is likely to continue to grow in importance and scope.

Pharmacogenomics of antimicrobial agents

Antimicrobial efficacy and toxicity varies between individuals owing to multiple factors. Genetic variants that affect drug-metabolizing enzymes may influence antimicrobial pharmacokinetics and pharmacodynamics, thereby determining efficacy and/or toxicity. In addition, many severe immune-mediated reactions have been associated with HLA class I and class II genes. In the last two decades, understanding of pharmacogenomic factors that influence antimicrobial efficacy and toxicity has rapidly evolved, leading to translational success such as the routine use of HLA-B*57:01 screening to prevent abacavir hypersensitivity reactions. This article examines recent advances in the field of antimicrobial pharmacogenomics that potentially affect treatment efficacy and toxicity, and challenges that exist between pharmacogenomic discovery and translation into clinical use.

Mitochondrial DNA mutations in ageing and disease: implications for HIV?

Mitochondrial DNA (mtDNA) mutations cause neurological and multisystem disease. Somatic (acquired) mtDNA mutations are also associated with degenerative diseases and with normal human ageing. It is well established that certain nucleoside reverse transcriptase inhibitor (NRTI) antiretroviral drugs cause inhibition of the mtDNA polymerase, pol γ, leading to a reduction in mtDNA content (depletion). Given this effect of NRTI therapy on mtDNA replication, it is plausible that NRTI treatment may also lead to increased mtDNA mutations. Here we review recent evidence for an effect of HIV infection or NRTI therapy on mtDNA mutations, as well as discussing the methodological challenges in addressing this question. Finally, we discuss the possible implications for HIV-infected persons, with particular reference to ageing.

The other genome: a systematic review of studies of mitochondrial DNA haplogroups and outcomes of HIV infection and antiretroviral therapy

Mitochondrial toxicity is implicated in some treatment-limiting antiretroviral therapy complications, and reports of mitochondrial dysfunction in untreated HIV infection suggest antiretroviral therapy independent effects of HIV. Several studies have explored associations between mtDNA haplogroups (patterns of mtDNA polymorphisms) and outcomes of HIV infection and/or antiretroviral therapy, but findings have been inconsistent. We systematically reviewed published studies examining mtDNA haplogroups in HIV-infected persons to summarize reported outcome associations, and to highlight potential future research directions. We identified 21 articles published from 2005-2013. Multiple different phenotypes were studied; most were antiretroviral therapy associated metabolic outcomes (e.g. lipodystrophy, insulin resistance, and dyslipidemia). Haplogroup H was associated with the most outcomes, including AIDS progression, CD4 T-cell recovery, cirrhosis (in hepatitis C coinfection), and metabolic outcomes. This review is the first to focus on the emerging area of mtDNA haplogroups in HIV, and summarizes the published literature on associations between mtDNA haplogroups and clinical outcomes in populations of European and African descent. Several reported associations require replication and ideally biological verification before definitive conclusions can be drawn, but research in this area has the potential to explain outcome disparities and impact clinical management of patients.

Contribution of genetic background, traditional risk factors, and HIV-related factors to coronary artery disease events in HIV-positive persons

BACKGROUND

Persons infected with human immunodeficiency virus (HIV) have increased rates of coronary artery disease (CAD). The relative contribution of genetic background, HIV-related factors, antiretroviral medications, and traditional risk factors to CAD has not been fully evaluated in the setting of HIV infection.

METHODS

In the general population, 23 common single-nucleotide polymorphisms (SNPs) were shown to be associated with CAD through genome-wide association analysis. Using the Metabochip, we genotyped 1875 HIV-positive, white individuals enrolled in 24 HIV observational studies, including 571 participants with a first CAD event during the 9-year study period and 1304 controls matched on sex and cohort.

RESULTS

A genetic risk score built from 23 CAD-associated SNPs contributed significantly to CAD (P = 2.9 × 10(-4)). In the final multivariable model, participants with an unfavorable genetic background (top genetic score quartile) had a CAD odds ratio (OR) of 1.47 (95% confidence interval [CI], 1.05-2.04). This effect was similar to hypertension (OR = 1.36; 95% CI, 1.06-1.73), hypercholesterolemia (OR = 1.51; 95% CI, 1.16-1.96), diabetes (OR = 1.66; 95% CI, 1.10-2.49), ≥ 1 year lopinavir exposure (OR = 1.36; 95% CI, 1.06-1.73), and current abacavir treatment (OR = 1.56; 95% CI, 1.17-2.07). The effect of the genetic risk score was additive to the effect of nongenetic CAD risk factors, and did not change after adjustment for family history of CAD.

CONCLUSIONS

In the setting of HIV infection, the effect of an unfavorable genetic background was similar to traditional CAD risk factors and certain adverse antiretroviral exposures. Genetic testing may provide prognostic information complementary to family history of CAD.

Pharmacogenetics of the lipodystrophy syndrome associated with HIV infection and combination antiretroviral therapy

INTRODUCTION

Antiretroviral drugs have been associated with several toxicities that limit their success. Of the chronic toxicities, the lipodystrophy syndrome is of special concern due to the metabolic alterations that can accompany it. Why some patients treated with a particular antiretroviral regimen develop lipodystrophy, while others do not, is a medical mystery, but it has been suggested that individuals may (or may not) have a genetically conditioned predisposition. Pharmacogenetics is the science that studies how the genetic composition of individuals can give rise to interindividual variations in response to drugs and drug toxicity.

AREAS COVERED

This article reviews the published investigations on the association between host genetic determinants in treated HIV-infected patients and the presence of lipodystrophy. Studies were identified through a PubMed database search. Case-control and longitudinal studies into pharmacogenetic association were selected. Areas covered include the data on the genetic variants of mitochondrial parameters, cytokines, adipokines, proteins involved in adipocyte biology and proteins involved in stavudine metabolism.

EXPERT OPINION

Most studies provide inconsistent data due to partial genetic evaluation, different assessment of lipodystrophy and low number of patients evaluated. The pharmacogenetics of lipodystrophy in HIV-infected patients treated with antiretroviral drugs still belongs in the research laboratory.

Ritonavir-induced lipoatrophy and dyslipidaemia is reversed by the anti-inflammatory drug leflunomide in a PPAR-γ-dependent manner

BACKGROUND

The complex interplay between viral infection and virus-activated inflammatory pathways with protease inhibitors (PIs) contributes to the increased risk of developing atherosclerosis and coronary artery disease in HIV-infected patients. Leflunomide is an antirheumatic drug whose administration to HIV-1-infected persons effectively decreases T-cell turnover and activation. In this study we have investigated the effects of leflunomide on dyslipidaemia and lipodistrophy induced by ritonavir in rodents.

METHODS

Mice were administered ritonavir (5 mg/kg/day) alone or in combination with leflunomide (40 mg/kg/day) for 12 days. Expression of nuclear receptor and lipidogenetic genes was measured in liver and adipose tissues.

RESULTS

Administration of the HIV PI ritonavir to mice increased plasma triacylglycerols, free fatty acids and cholesterol levels, and this effect was reverted by cotreatment with leflunomide. Ritonavir administration was associated with reduced epididymal fat/body weight ratio and increased liver content of triacylglycerols content. These effects were reverted by leuflunomide. Histopathology analysis shows that exposure to ritonavir causes inflammation of epididymal fat as demonstrated by dense leukocytes infiltration as well as by increased levels of proinflammatory mediators and reduced expression and activity of peroxisome proliferator-activated receptor-γ (PPAR-γ). Leflunomide reduced epididymal fat inflammatory-metabolic alteration induced by ritonavir and restored PPAR-γ expression in the epididymal fat.

CONCLUSIONS

We have shown that the anti-inflammatory drug leflunomide protects against ritonavir-induced inflammation and dysmetabolism in adipose tissue and might be a promising strategy in the setting of HIV-infected patients at risk for HIV-induced dyslipidaemia.