Impact of genetic factors on dyslipidemia in HIV-infected patients starting antiretroviral therapy

Contribution of APOA5, APOC3, CETP, ABCA1 and SIK3 genetic variants to hypertriglyceridemia development in Mexican HIV-patients receiving antiretroviral therapy

OBJECTIVE

To investigate the impact of single nucleotide polymorphisms (SNPs) from APOA5, APOC3, CETP, ATP binding cassette transporter A1 and SIK3 genes in the development of hypertriglyceridemia in HIV patients under antiretroviral therapy.

MATERIAL AND METHODS

A case-control study was developed. Leukocytic genomic DNA was extracted and genotyping for SNPs rs662799, rs964184, rs5128, rs2854116, rs2854117, rs3764261, rs4149310, rs4149267 and rs139961185 was performed by real time-PCR using TaqMan allelic discrimination assays, in Mexican mestizo patients with HIV infection, with hypertriglyceridemia (>1.7 mmol/L) under antiretroviral therapy. Genetic variants were also investigated in a control group of normolipidemic HIV patients (≤ 1.7 mmol/L). Haplotypes and gene interactions were analyzed.

RESULTS

A total of 602 HIV patients were genotyped (316 cases and 286 controls). Age and antiretroviral regimen based on protease inhibitors were associated with hypertriglyceridemia (P = 0.0001 and P = 0.0002. respectively). SNP rs964184 GG genotype in APOA5 gene exhibited the highest association with hypertriglyceridemia risk (OR, 3.2, 95% CI, 1.7-5.8, P = 0.0001); followed by SNP rs139961185 in SIK3 gene (OR = 2.3; (95% CI, 1.1-4.8; P = 0.03 for AA vs. AG genotype; and APOC3 rs5128 GG genotype, (OR, 2.2; 95% CI, 1.1-4.9; P = 0.04) under codominant models. These associations were maintained in the adjusted analysis by age and protease inhibitors based antiretroviral regimens.

CONCLUSIONS

This study reveals an association between rs964184 in APOA5; rs5128 in APOC3 and rs139961185 in SIK3 and high triglyceride concentrations in Mexican HIV-patients receiving protease inhibitors. These genetic factors may influence the adverse effects related to antiretroviral therapy.

miRNA Expression Profiling in Subcutaneous Adipose Tissue of Monozygotic Twins Discordant for HIV Infection: Validation of Differentially Expressed miRNA and Bioinformatic Analysis

Combined AntiRetroviral Treatments (cARTs) used for HIV infection may result in varied metabolic complications, which in some cases, may be related to patient genetic factors, particularly microRNAs. The use of monozygotic twins, differing only for HIV infection, presents a unique and powerful model for the controlled analysis of potential alterations of miRNAs regulation consequent to cART treatment. Profiling of 2578 mature miRNA in the subcutaneous (SC) adipose tissue and plasma of monozygotic twins was investigated by the GeneChip® miRNA 4.1 array. Real-time PCR and ddPCR experiments were performed in order to validate differentially expressed miRNAs. Target genes of deregulated miRNAs were predicted by the miRDB database (prediction score > 70) and enrichment analysis was carried out with g:Profiler. Processes in SC adipose tissue most greatly affected by miRNA up-regulation included (i) macromolecular metabolic processes, (ii) regulation of neurogenesis, and (iii) protein phosphorylation. Furthermore, KEGG analysis revealed miRNA up-regulation involvement in (i) insulin signaling pathways, (ii) neurotrophin signaling pathways, and (iii) pancreatic cancer. By contrast, miRNA up-regulation in plasma was involved in (i) melanoma, (ii) p53 signaling pathways, and (iii) focal adhesion. Our findings suggest a mechanism that may increase the predisposition of HIV+ patients to insulin resistance and cancer.

The Role of the ATP-Binding Cassette A1 (ABCA1) in Human Disease

Cholesterol homeostasis is essential in normal physiology of all cells. One of several proteins involved in cholesterol homeostasis is the ATP-binding cassette transporter A1 (ABCA1), a transmembrane protein widely expressed in many tissues. One of its main functions is the efflux of intracellular free cholesterol and phospholipids across the plasma membrane to combine with apolipoproteins, mainly apolipoprotein A-I (Apo A-I), forming nascent high-density lipoprotein-cholesterol (HDL-C) particles, the first step of reverse cholesterol transport (RCT). In addition, ABCA1 regulates cholesterol and phospholipid content in the plasma membrane affecting lipid rafts, microparticle (MP) formation and cell signaling. Thus, it is not surprising that impaired ABCA1 function and altered cholesterol homeostasis may affect many different organs and is involved in the pathophysiology of a broad array of diseases. This review describes evidence obtained from animal models, human studies and genetic variation explaining how ABCA1 is involved in dyslipidemia, coronary heart disease (CHD), type 2 diabetes (T2D), thrombosis, neurological disorders, age-related macular degeneration (AMD), glaucoma, viral infections and in cancer progression.

Current pharmacotherapy for the treatment of dyslipidemia associated with HIV infection

Introduction: Cardiovascular disease is an important cause of morbidity and mortality in persons with human immunodeficiency virus (PWH). The risk of atherosclerotic cardiovascular disease (ASCVD) is higher in PWH compared to uninfected persons. Dyslipidemia is a critical link in the pathogenesis of ASCVD in PWH. Chronic inflammation associated with HIV infection may drive both dyslipidemia and ASCVD. Areas covered: The authors review the evidence for using lipid-lowering therapy in PWH and includes an overview of the utility and complexity of using statins in PWH, in particular, drug interactions, safety, and efficacy. In addition, data covering alternate therapies like omega-3 fatty acids, fibrates, niacin, ezetimibe, and PCSK-9 inhibitors are reviewed. Expert opinion: Dyslipidemia is a common problem in PWH. The risk of ASCVD is higher in PWH. Lipid-lowering therapy reduces the risk of ASCVD, but clinical endpoint trials are lacking in PWH. Statin therapy is the mainstay of primary prevention for ASCVD. The timing of when to initiate primary prevention with statins in PWH is unclear. Beyond statins, there are limited data that other lipid-lowering agents have utility in PWH. Ongoing trials like the REPRIEVE trial will inform the community about the optimal approach to lipid-lowering therapy in PWH.

Subset-Based Analysis Using Gene-Environment Interactions for Discovery of Genetic Associations across Multiple Studies or Phenotypes

OBJECTIVES

Classical methods for combining summary data from genome-wide association studies only use marginal genetic effects, and power can be compromised in the presence of heterogeneity. We aim to enhance the discovery of novel associated loci in the presence of heterogeneity of genetic effects in subgroups defined by an environmental factor.

METHODS

We present a pvalue-assisted subset testing for associations (pASTA) framework that generalizes the previously proposed association analysis based on subsets (ASSET) method by incorporating gene-environment (G-E) interactions into the testing procedure. We conduct simulation studies and provide two data examples.

RESULTS

Simulation studies show that our proposal is more powerful than methods based on marginal associations in the presence of G-E interactions and maintains comparable power even in their absence. Both data examples demonstrate that our method can increase power to detect overall genetic associations and identify novel studies/phenotypes that contribute to the association.

CONCLUSIONS

Our proposed method can be a useful screening tool to identify candidate single nucleotide polymorphisms that are potentially associated with the trait(s) of interest for further validation. It also allows researchers to determine the most probable subset of traits that exhibit genetic associations in addition to the enhancement of power.

Interactions among genes involved in reverse cholesterol transport and in the response to environmental factors in dyslipidemia in subjects from the Xinjiang rural area

Gene-gene and gene-environment interactions may be partially responsible for dyslipidemia, but studies investigating interactions in the reverse cholesterol transport system (RCT) are limited. We explored these interactions in a Xinjiang rural population by genotyping five SNPs using SNPShot technique in APOA1, ABCA1, and LCAT, which are involved in the RCT (690 patients, 743 controls). We conducted unconditional logistical regression analysis to evaluate associations and generalized multifactor dimensionality reduction to evaluate interactions. Results revealed significant differences in rs670 and rs2292318 allele frequencies between cases and controls (P<0.025). rs670 G allele carriers were more likely to develop dyslipidemia than A allele carriers (OR = 1.315, OR 95% CI: 1.067–2.620; P = 0.010). rs2292318 T allele carriers were more likely to develop dyslipidemia than A allele carriers (OR = 1.264, OR 95% CI: 1.037–1.541; P = 0.020). Gene-gene interaction model APOA1rs670-ABCA1rs1800976-ABCA1rs4149313-LCATrs1109166 (P = 0.0107) and gene-environment interaction model ABCA1rs1800976-ABCA1rs4149313-LCATrs1109166-obesity-smoking were optimal dyslipidemia predictors (P = 0.0107) and can interact (4). Differences in A-C-A-C-A and G-G-G-T-G haplotype frequencies were observed (P<0.05). Serum lipid profiles could be partly attributed to RCT gene polymorphisms. Thus, dyslipidemia is influenced by APOA1, ABCA1, LCAT, environmental factors, and their interactions.

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.

Deciphering the molecular mechanisms involved in HIV-associated lipoatrophy by transcriptomics: a pilot study

HIV-associated lipoatrophy (LA) has considerable implications for risk of metabolic diseases, quality of life, and adherence to treatments. Although it has decreased in high-income countries, it is still very common in resource-limited countries. Understanding the pathophysiological mechanisms of LA can open the possibility to explore new ways to treat or prevent this condition. To identify new markers for an accurate and quick diagnosis will be also of interest. Thus, we aimed to examine functional classes of genes implicated in LA and to identify potential new markers for an accurate/quick diagnosis of LA and future complications. Eighteen participants were recruited: seven healthy volunteers, five non-LA-HIV patients, and six LA-HIV subjects. Clinical lipoatrophy was considered when changes in fat volume in the cheeks next to the nose, lateral aspect of the face, legs, arms, and buttocks were observed by the physicians. mRNA was isolated from peripheral blood mononuclear cells (PBMCs) to perform a transcriptomic and Gene Ontology analysis. To confirm RNA sequencing results, qPCRs were developed. A total of 55 genes were differentially expressed between LA and non-LA patients. Thirty-seven genes were overexpressed, whereas 18 genes were repressed. Functional analysis showed that overexpressed genes were involved in lymphocyte/neutrophil activation, inflammation, and atherogenesis. Several lymphoma markers and members of the lipocalin and aquaporin families were also found more expressed in LA patients. In contrast, most of the genes found less expressed in LA subjects were involved in angiogenesis and protection against myocardial infarction. Our results demonstrated a distinct transcriptomic signature in PBMCs of LA patients in comparison with non-LA-HIV subjects and, therefore, provided novel insights to the pathogenesis of HIV-associated lipoatrophy. Our study also highlights the potential usage of some of these genes as early markers of future complications.

Pharmacogenetic considerations in the treatment of HIV

After the introduction of highly active antiretroviral therapy in the 1990s, the perception of the diagnosis of HIV infection gradually shifted from a 'death sentence' to a chronic disease requiring long-term treatment. The host genetic variability has been shown to play a relevant role in both antiretroviral drugs bioavailability and adverse effects susceptibility. Knowledge about pharmacogenetics role in HIV infection treatment has largely increased over the last years, and is reviewed in the present report, as well as future perspectives for the inclusion of pharmacogenetics information in the directing of HIV infection treatment.

Clinical management of dyslipidaemia associated with combination antiretroviral therapy in HIV-infected patients

The introduction of potent combination antiretroviral therapy (cART) has had a remarkable impact on the natural history of HIV infection, leading to a dramatic decline in the mortality rate and a considerable increase in the life expectancy of HIV-positive people. However, cART use is frequently associated with several metabolic complications, mostly represented by lipid metabolism alterations, which are reported very frequently among persons treated with antiretroviral agents. In particular, hyperlipidaemia occurs in up to 70%-80% of HIV-positive subjects receiving cART and is mainly associated with specific antiretroviral drugs belonging to three classes of antiretroviral agents: NRTIs, NNRTIs and PIs. The potential long-term consequences of cART-associated dyslipidaemia are not completely understood, but an increased risk of premature coronary heart disease has been reported in HIV-infected patients on cART, so prompt correction of lipid metabolism abnormalities is mandatory in this population. Dietary changes, regular aerobic exercise and switching to a different antiretroviral regimen associated with a more favourable metabolic profile are the first steps in clinical management, but lipid-lowering therapy with fibrates or statins is often required. In this case, the choice of hypolipidaemic drugs should take into account the potential pharmacokinetic interactions with many antiretroviral agents.

Lipid levels in HIV-positive men receiving anti-retroviral therapy are not associated with copy number variation of reverse cholesterol transport pathway genes

BACKGROUND

The exacerbation of HIV-1 associated dyslipidemia seen in a subset of patients receiving anti-retroviral therapy suggests that genetic factors put these individuals at greater risk of cardiovascular disease. Single nucleotide polymorphisms (SNPs) within genes of and influencing the reverse cholesterol transport (RCT) pathway are associated with lipid levels but little is known regarding their copy number variation (CNV). This form of quantitative genetic variation has the potential to alter the amount of gene product made, thereby also influencing lipid metabolism.

RESULTS

To examine if CNV in RCT pathway genes was associated with altered serum lipid profiles in HIV-positive individuals receiving therapy, we designed a custom multiplex ligation-dependent probe amplification assay to screen 16 RCT genes within a subset of individuals from the Multicenter AIDS Cohort Study who show extreme lipid phenotypes. Verification of CNV was performed using a custom NanoString assay, and the Illumina HT-12 mRNA expression microarray was used to determine the influence of copy number on gene expression. Among the RCT genes, CNV was observed to be extremely rare. The only CNV seen was in the CETP gene, which showed a loss of copy in 1 of the 320 samples (0.3%) in our study. The genes in our study showed little variation in expression between individuals, and the variation seen was not related to any detected CNV.

CONCLUSIONS

Whole gene CNV is uncommon in RCT pathway genes, and not a major factor in the development of highly active antiretroviral therapy (HAART) associated dyslipidemia.

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.

Improvement of lipoatrophy by switching from efavirenz to lopinavir/ritonavir

OBJECTIVE

To assess whether changes in antiretroviral drugs other than thymidine nucleoside reverse transcriptase inhibitors (NRTI) may have a body fat impact in HIV-infected patients with lipoatrophy.

METHODS

Ninety-six-week phase IV, open-label, multicentre, pilot randomized trial. HIV-infected patients with moderate/severe lipoatrophy at one or more body sites despite long-term thymidine NRTI-free therapy were randomized to continue their efavirenz (EFV)-based antiretroviral regimen or to switch from EFV to lopinavir/ritonavir (LPV/r). The primary endpoint was the absolute change in limb fat mass measured by dual X-ray absorptiometry from baseline to 96 weeks. Changes in other body fat measurements, subjective perception of lipoatrophy, subcutaneous fat gene expression and plasma lipids were also assessed.

RESULTS

Thirty-three patients (73% men, median age 52 years) were recruited. At 96 weeks, absolute limb fat mass increased in the LPV/r arm vs. the EFV arm (estimated difference +1082.1 g; 95% CI +63.7 to +2103.5; P = 0.04); this difference remained significant after adjustment by gender, age, fat mass, body mass index and CD4 cell count at baseline. Subjective lipoatrophy perception scores also improved in the LPV/r arm relative to the EFV arm. Adipogenesis, glucose and lipid metabolism, and mitochondrial gene expression increased in the LPV/r arm compared with the EFV arm at 96 weeks. HDL cholesterol decreased in the LPV/r arm relative to the EFV arm.

CONCLUSIONS

Switching from EFV to LPV/r in HIV-infected patients with lipoatrophy may offer further limb fat gain beyond thymidine NRTI discontinuation, although this strategy decreased plasma HDL cholesterol and caused changes in subcutaneous fat gene expression that may be associated with increased insulin resistance.

Can antiretroviral therapy be tailored to each human immunodeficiency virus-infected individual? Role of pharmacogenomics

Pharmacogenetics refers to the effect of single nucleotide polymorphisms (SNPs) within human genes on drug therapy outcome. Its study might help clinicians to increase the efficacy of antiretroviral drugs by improving their pharmacokinetics and pharmacodynamics and by decreasing their side effects. HLAB*5701 genotyping to avoid the abacavir-associated hypersensitivity reaction (HSR) is a cost-effective diagnostic tool, with a 100% of negative predictive value, and, therefore, it has been included in the guidelines for treatment of human immunodeficiency virus (HIV) infection. HALDRB*0101 associates with nevirapine-induced HSR. CYP2B6 SNPs modify efavirenz plasma levels and their genotyping help decreasing its central nervous system, hepatic and HSR toxicities. Cytokines SNPs might influence the development of drug-associated lipodystrophy. APOA5, APOB, APOC3 and APOE SNPs modify lipids plasma levels and might influence the coronary artery disease risk of HIV-infected individuals receiving antiretroviral therapy. UGT1A1*28 and ABCB1 (MDR1) 3435C > T SNPs modify atazanavir plasma levels and enhance hyperbilirubinemia. Much more effort needs to be still devoted to complete large prospective studies with multiple SNPs genotyping in order to reveal more clues about the role played by host genetics in antiretroviral drug efficacy and toxicity.

Dyslipidemia and cardiovascular disease risk profiles of patients attending an HIV treatment clinic in Harare, Zimbabwe

The chronic inflammation induced by human immunodeficiency virus (HIV) contributes to increased risk of coronary heart disease (CHD) in HIV-infected individuals. HIV-infected patients generally benefit from being treated with antiretroviral drugs, but some antiretroviral agents have side effects, such as dyslipidemia and hyperglycemia. There is general consensus that antiretroviral drugs induce a long-term risk of CHD, although the levels of that risk are somewhat controversial. The intention of this cross-sectional study was to describe the lipid profile and the long-term risk of CHD among HIV-positive outpatients at an HIV treatment clinic in Harare, Zimbabwe. Two hundred and fifteen patients were investigated (females n=165, mean age 39.8 years; males n=50; mean age 42.0 years). Thirty of the individuals were antiretroviral-naïve and 185 had been on antiretroviral therapy (ART) for a mean 3.9±3.4 years. All participants had average lipid and glucose values within normal ranges, but there was a small difference between the ART and ART-for total cholesterol (TC) and high-density lipoprotein (HDL). Those on a combination of D4T or ZDV/NVP/3TC and PI-based ART were on average oldest and had the highest TC levels. Framingham risk showed 1.4% prevalence of high CHD risk within the next ten years. After univariate analysis age, sex, TC/HDL ratio, HDL, economic earnings and systolic BP were associated with medium to high risk of CHD. After multivariate regression analysis and adjusting for age or sex only age, sex and economic earnings were associated with medium to high risk of CHD. There is small risk of developing CHD, during the next decade in HIV infected patients at an HIV treatment clinic in Harare.

Impact of antiretroviral therapy on lipid metabolism of human immunodeficiency virus-infected patients: Old and new drugs

For human immunodeficiency virus (HIV)-infected patients, the 1990s were marked by the introduction of highly active antiretroviral therapy (HAART) representing a new perspective of life for these patients. The use of HAART was shown to effectively suppress the replication of HIV-1 and dramatically reduce mortality and morbidity, which led to a better and longer quality of life for HIV-1-infected patients. Apart from the substantial benefits that result from the use of various HAART regimens, laboratory and clinical experience has shown that HAART can induce severe and considerable adverse effects related to metabolic complications of lipid metabolism, characterized by signs of lipodystrophy, insulin resistance, central adiposity, dyslipidemia, increased risk of cardiovascular disease and even an increased risk of atherosclerosis. New drugs are being studied, new therapeutic strategies are being implemented, and the use of statins, fibrates, and inhibitors of intestinal cholesterol absorption have been effective alternatives. Changes in diet and lifestyle have also shown satisfactory results.

Association between polymorphisms in genes involved in lipid metabolism and immunological status in chronically HIV-infected patients

Several studies have reported associations between lipid parameters and clinical progression of HIV infection. We performed a cross-sectional study including 468 antiretroviral-treated HIV-infected patients to investigate the impact of 13 polymorphisms of 9 genes affecting lipid metabolism and CD4 and CD8-T cell levels. Polymorphisms were identified in genes selected for their role in the development of atherogenic dyslipidemia, defined as triglycerides ⩾1.7mmol/L and high-density lipoprotein cholesterol (HDLc) <1.02 in women or 1.28mmol/L in men. Lipid and lipoprotein parameters were determined in all participants, as well as CD4 and CD8 T-cell counts. ANOVA was performed to compare the mean values of lipid and CD4 and CD8 T-cell count data. A Bonferroni correction for multiple comparisons was applied. 468 patients were included, 148 of them had a diagnosis of atherogenic dyslipidemia. The polymorphism rs3135506 in APOA5 was associated with a 9% increase in triglycerides (p=0.002), 10% and 21% decrease in HDLc (p=0.005), and CD4 T-cell count (p=0.024), respectively. APOA5 rs662799, was associated with a 19% increase in CD8 T-cell count (p=0.002). Carriers of LPL rs328 in the dyslipidemic group presented 11% higher levels of HDLc (p=0.015) and 14% higher levels of CD4 cells (p=0.038). In conclusion, polymorphisms in genes associated to the development of atherogenic dyslipidemia, especially variants in APOA5 gene (rs3135506 and rs662799), can influence the circulating CD4 T-cell levels in chronically HIV-infected patients. These data support previous reports on the effect of lipid metabolism on immunologic parameters in HIV+ individuals on antiretroviral therapy.

HIV and metabolic, body, and bone disorders: what we know from low- and middle-income countries

Globally, the HIV epidemic is evolving. Life expectancy for HIV-infected individuals has been extended because of more effective and more widely available antiretroviral therapy. As a result, chronic noncommunicable diseases (NCDs) have become important comorbid conditions. In particular, HIV-infected persons are increasingly at risk of developing metabolic (diabetes, dyslipidemias), body composition (lipodystrophy, overweight/obesity) and bone mineral density abnormalities. We have summarized the published epidemiological and clinical literature regarding these HIV-NCD comorbidities in low- and middle-income countries (LMICs). We found important gaps in knowledge. Specifically, there are few studies that use standardized methods and metrics; consequently, prevalence or incidence data are not comparable. There are very little or no data regarding the effectiveness or cost-effectiveness of clinical monitoring or therapeutic interventions for metabolic disorders in HIV-infected individuals. Also, although NCDs continue to grow in the HIV-negative population of most LMICs, there are few data comparing the incidence of NCD comorbidities between HIV-infected and HIV-negative populations. To address these gaps, we describe potential research and capacity development priorities for the future.

Dyslipidemia and cardiovascular risk in human immunodeficiency virus infection

The pathogenesis of atherosclerosis in human immunodeficiency virus (HIV)-infected individuals is incompletely understood and appears to be multifactorial. Proatherogenic changes in blood and tissue lipids are associated with an increased risk of cardiovascular disease among HIV-infected subjects, and these changes may be both quantitative (dyslipidemia) and qualitative. In view of the pivotal role of dyslipidemia in the process of atherosclerosis, the increased incidence of dyslipidemia in HIV-infected individuals, and the emerging role of lipid abnormalities in systemic pathophysiologic processes such as immune activation, we review the contributions of dyslipidemia to cardiovascular risk in HIV infection.

Differential subcutaneous adipose tissue gene expression patterns in a randomized clinical trial of efavirenz or lopinavir-ritonavir in antiretroviral-naive patients

Gene expression studies of subcutaneous adipose tissue may help to better understand the mechanisms behind body fat changes in HIV-infected patients who initiate antiretroviral therapy (ART). Here, we evaluated early changes in adipose tissue gene expression and their relationship to fat changes in ART-naive HIV-infected patients randomly assigned to initiate therapy with emtricitabine/tenofovir plus efavirenz (EFV) or ritonavir-boosted lopinavir (LPV/r). Patients had abdominal subcutaneous adipose tissue biopsies at baseline and week 16 and dual-energy-X-ray absorptiometry at baseline and weeks 16 and 48. mRNA changes of 11 genes involved in adipogenesis, lipid and glucose metabolism, mitochondrial energy, and inflammation were assessed through reverse transcription-quantitative PCR (RT-qPCR). Additionally, correlations between gene expression changes and fat changes were evaluated. Fat increased preferentially in the trunk with EFV and in the limbs with LPV/r (P < 0.05). After 16 weeks of exposure to the drug regimen, transcripts of CEBP/A, ADIPOQ, GLUT4, LPL, and COXIV were significantly down-regulated in the EFV arm compared to the LPV/r arm (P < 0.05). Significant correlations were observed between LPL expression change and trunk fat change at week 16 in both arms and between CEBP/A or COXIV change and trunk fat change at the same time point only in the EFV arm and not in the LPV/r arm. When combined with emtricitabine/tenofovir as standard backbone therapy, EFV and LPV/r induced differential early expression of genes involved in adipogenesis and energy metabolism. Moreover, these mRNA expression changes correlated with trunk fat change in the EFV arm. (This was a substudy of a randomized clinical trial [LIPOTAR study] registered at ClinicalTrials.gov under identifier NCT00759070.).

Contribution of genetic background and antiretroviral therapy to body fat changes in antiretroviral-naive HIV-infected adults

OBJECTIVES

To evaluate the association of host genetics with changes in limb or trunk fat in a group of antiretroviral therapy (ART)-naive HIV-infected patients prospectively followed up according to the initiation and the type of ART.

METHODS

Fifty single nucleotide polymorphisms (SNPs) in 26 genes, associated with obesity, insulin resistance, lipid metabolism or lipodystrophy in previously published genetic studies, were assessed in ART-naive HIV-infected Caucasian patients divided into three groups: 24 (27%) did not start ART, 29 (32.6%) received zidovudine or stavudine and 36 (40.4%) received neither zidovudine nor stavudine in their initial regimen. Patients underwent body fat measurements (using dual-energy X-ray absorptiometry) at baseline and Month 12. A multivariate model using backward stepwise elimination was used to assess the influence of SNPs and baseline levels of non-genetic covariates on changes in limb or trunk fat.

RESULTS

The baseline characteristics were: 73% men, 17% coinfected with hepatitis C virus and/or hepatitis B virus, median age 37 years, median CD4+ T cell count 228/mm(3), median HIV-RNA 5.2 log copies/mL, median plasma glucose 85 mg/dL, median plasma insulin 9.1 IU/mL, median limb fat 5.6 kg and median trunk fat 7.0 kg. There were no baseline differences among the three groups except for the CD4+ T cell count. The decrease in limb fat was greater in the no-ART group relative to the other two groups (P < 0.05). The multivariate model showed associations of rs1801278 in IRS1 (P = 0.029, OR = 0.13), baseline viral load (P = 0.006; OR = 4.453) and baseline glucose levels (P = 0.008, OR = 0.926) with loss of limb fat, and rs2228671 in LDLR (P = 0.012, OR = 0.108), rs405509 in APOE (P = 0.048, OR = 0.205), baseline viral load (P = 0.005, OR = 0.186) and baseline CD4+ T cell count (P = 0.01, OR = 1.008) with gain of trunk fat.

CONCLUSIONS

Specific polymorphisms in IRS1 (limb fat loss) and LDLR and APOE (trunk fat gain) were identified as independent markers of fat changes irrespective of the initiation of ART and the type of ART and deserve further validation.

Early lipid changes with atazanavir/ritonavir or darunavir/ritonavir

OBJECTIVES

Ritonavir-boosted atazanavir and darunavir are protease inhibitors that are recommended for initial treatment of HIV infection because each has shown better lipid effects and overall tolerability than ritonavir-boosted lopinavir. The extent to which lipid effects and overall tolerability differ between treatments with atazanavir and darunavir and whether atazanavir-induced hyperbilirubinaemia may result in more favourable metabolic effects are issues that remain to be resolved.

METHODS

A 96-week randomized clinical trial was carried out. The primary endpoint was change in total cholesterol at 24 weeks. Secondary endpoints were changes in lipids other than total cholesterol, insulin sensitivity, total bilirubin, estimated glomerular filtration rate, and CD4 and CD8 cell counts, and the proportion of patients with plasma HIV RNA < 50 HIV-1 RNA copies/mL and study drug discontinuation because of adverse effects at 24 weeks. Analyses were intent-to-treat.

RESULTS

One hundred and seventy-eight patients received once-daily treatment with either atazanavir/ritonavir (n = 90) or darunavir/ritonavir (n = 88) plus tenofovir/emtricitabine. At 24 weeks, mean total cholesterol had increased by 7.26 and 11.47 mg/dL in the atazanavir/ritonavir and darunavir/ritonavir arms, respectively [estimated difference -4.21 mg/dL; 95% confidence interval (CI) -12.11 to +3.69 mg/dL; P = 0.75]. However, the ratio of total to high-density lipoprotein (HDL) cholesterol tended to show a greater decrease with atazanavir/ritonavir compared with darunavir/ritonavir (estimated difference -1.02; 95% CI -2.35 to +0.13; P = 0.07). Total bilirubin significantly increased with atazanavir/ritonavir (estimated difference +1.87 mg/dL; 95% CI +1.58 to +2.16 mg/dL; P < 0.01), but bilirubin changes were not associated with lipid changes. Secondary endpoints other than total bilirubin were not significantly different between arms.

CONCLUSIONS

Atazanavir/ritonavir and darunavir/ritonavir plus tenofovir/emtricitabine did not show significant differences in total cholesterol change or overall tolerability at 24 weeks. However, there was a trend towards a lower total to HDL cholesterol ratio with atazanavir/ritonavir and this effect was unrelated to bilirubin.

The roles of genetic polymorphisms and human immunodeficiency virus infection in lipid metabolism

Dyslipidemia has been frequently observed among individuals infected with human immunodeficiency virus type 1 (HIV-1), and factors related to HIV-1, the host, and antiretroviral therapy (ART) are involved in this phenomenon. This study reviews the roles of genetic polymorphisms, HIV-1 infection, and highly active antiretroviral therapy (HAART) in lipid metabolism. Lipid abnormalities can vary according to the HAART regimen, such as those with protease inhibitors (PIs). However, genetic factors may also be involved in dyslipidemia because not all patients receiving the same HAART regimen and with comparable demographic, virological, and immunological characteristics develop variations in the lipid profile. Polymorphisms in a large number of genes are involved in the synthesis of structural proteins, and enzymes related to lipid metabolism account for variations in the lipid profile of each individual. As some genetic polymorphisms may cause dyslipidemia, these allele variants should be investigated in HIV-1-infected patients to identify individuals with an increased risk of developing dyslipidemia during treatment with HAART, particularly during therapy with PIs. This knowledge may guide individualized treatment decisions and lead to the development of new therapeutic targets for the treatment of dyslipidemia in these patients.