Contribution of 20 single nucleotide polymorphisms of 13 genes to dyslipidemia associated with 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.

APOC3 Gene Polymorphism and Antiretroviral Therapy-Induced Dyslipidemia in HIV-Infected Children

Children exposed to antiretroviral therapy (ART) are at risk of developing metabolic complications. The association between gene polymorphisms and the development of dyslipidemia in children post ART initiation was studied. Children initiating first-line ART were followed for 2 years at the National Institute for Research in Tuberculosis (Chennai, India), and St. John's Medical College Hospital (Bangalore, India). Clinical examination and fasting serum lipid profiles were measured every 6 months. Participants were genotyped for the polymorphisms in the APOC3 gene (rs2854116; rs2854117, and rs5128). Changes in lipid levels from baseline to months 6, 12, and 24, and the difference between the various genotype variants were analyzed using a modified analysis of variance test. Study enrolled 393 ART-naive HIV-infected children (mean age: 7.6 ± 3 years, mean weight: 18 ± 6) of whom 289 (75%) were started on nevirapine (NVP)-based ART and the remaining 96 (25%) were started on efavirenz-based ART. Only children carrying the GG allele of rs5128 genotype showed a decrease in CD4% and serum triglycerides pre-ART. An increasing trend of total cholesterol, high-density lipoprotein cholesterol (HDL-c), and low-density lipoprotein cholesterol were seen at 6 months in both EFZ and NVP groups, which subsequently stabilized by 12 months irrespective of genotype variants. Genotype variants of APOC3 (rs2854116 and rs2854117 polymorphism) did not show significant changes in serum lipid levels after 24 months of ART, whereas rs5128 polymorphism with "G" allele showed an association with HDL-c levels when on NVP-based ART. Our results suggest that ART plays a major role in normalizing lipid levels in HIV-infected children and APOC3 polymorphisms may not play a significant role in ART-induced dyslipidemia.

Rapid Progression of Kidney Dysfunction in People Living With HIV: Use of Polygenic and Data Collection on Adverse Events of Anti-HIV Drugs (D:A:D) Risk Scores

BACKGROUND

In people with human immunodeficiency virus (PWH), it is unknown whether genetic background associates with rapid progression of kidney dysfunction (ie, estimated glomerular filtration rate [eGFR] decrease of >5mL/min/1.73m2 per year for ≥3 consecutive years).

METHODS

We obtained univariable and multivariable hazard ratios (HR) for rapid progression, based on the clinical D:A:D chronic kidney disease (CKD) risk score, antiretroviral exposures, and a polygenic risk score based on 14 769 genome-wide single nucleotide polymorphisms in white Swiss HIV Cohort Study participants.

RESULTS

We included 225 participants with rapid progression and 3378 rapid progression-free participants. In multivariable analysis, compared to participants with low D:A:D risk, participants with high risk had rapid progression (HR =  1.82 [95% CI, 1.28-2.60]). Compared to the first (favorable) polygenic risk score quartile, participants in the second, third, and fourth (unfavorable) quartiles had rapid progression (HR = 1.39 [95% CI, 0.94-2.06], 1.52 [95% CI, 1.04-2.24], and 2.04 [95% CI, 1.41-2.94], respectively). Recent exposure to tenofovir disoproxil fumarate was associated with rapid progression (HR = 1.36 [95% CI, 1.06-1.76]).

DISCUSSION

An individual polygenic risk score is associated with rapid progression in Swiss PWH, when analyzed in the context of clinical and antiretroviral risk factors.

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.

Individualization of antiretroviral therapy--pharmacogenomic aspect

Combination therapy with three drug regimens for human immunodeficiency virus (HIV) infection significantly suppresses the viral replication. However, this therapeutic impact is restricted by adverse drug events and response in terms of short and long term efficacy. There are multiple factors involved in different responses to antiretrovirals (ARVs) such as age, body weight, disease status, diet and heredity. Pharmacogenomics deals with individual genetic make-up and its role in drug efficacy and toxicity. In depth genetic research has provided evidence to predict the risk of developing certain toxicities for which personalized screening and surveillance protocols may be developed to prevent side effects. Here we describe the use of pharmacogenomics for optimal use of HAART (highly active antiretroviral therapy).

Apolipoprotein B Gene Polymorphisms and Dyslipidemia in HIV Infected Adult Zimbabweans

Background:

Dyslipidemia does not occur in all HIV-infected or antiretroviral therapy-experienced patients suggesting role of host genetic factors but there is paucity of data on association between dyslipidemia and gene polymorphisms in Zimbabwe.

Objective:

To determine association of lipoprotein levels and apolipoprotein B polymorphisms in HIV-infected adults.

Method:

Demographic data were collected from 103 consenting patients; lipoprotein levels were determined and blood samples were successfully genotyped for both apolipoprotein B 2488C>T Xba1 and apolipoprotein B 4154G>A p.Gln4154Lys EcoR1 polymorphisms by real time polymerase chain reaction.

Results:

Mean age of genotyped patients was 40.3 ± 10.1 years, 68% were female; prevalence of dyslipidemia was 67.4%. Of 103 samples genotyped for apolipoprotein B Xba1 polymorphism, 76 (74%) were homozygous C/C, 24 (23%) were heterozygous C/T and only three (3%) were homozygous T/T. Apolipoprotein B EcoR1 polymorphism showed little variability, one participant had rare genotype A/A, 68.3% had wild type genotype G/G.

Conclusion:

Observed frequencies of apolipoprotein B XbaI and EcoRI polymorphisms matched other African studies. In spite of low numbers of rare variants, there was positive association between both total cholestrol and high density lipoprotein with ECoR1 wild type G/G genotype, suggesting that ECoRI 4154 G allele could be more protective against coronary heart disease than EcoR1 4154 A allele. There is need for further research at population level to confirm whether apolipoprotein B ECoR1 genotyping is useful for predicting risk of dyslipidemia in HIV patients in our setting.

Association of immune recovery with hyperlipidaemia and apolipoprotein gene polymorphisms following highly active antiretroviral therapy in a cohort of Chinese HIV patients

OBJECTIVE

To examine the associations between CD4 recovery, dyslipidaemia and apolipoprotein (APO) gene single nucleotide polymorphisms (SNPs) following highly active antiretroviral therapy (HAART).

DESIGN

Retrospective observational cohort study.

SETTING

A major HIV care clinic in Hong Kong.

PARTICIPANTS

197 Chinese treatment-naïve HIV patients.

OUTCOME MEASURES

Maximum CD4 count and its rise 2-3 years after HAART initiation and their association with abnormal total cholesterol (TC), triglyceride (TG) and 8 selected APO SNP at multiple time points.

RESULTS

Before HAART, abnormal levels of TC, TG, high-density lipoprotein cholesterol and low-density lipoprotein cholesterol were detected in 13%, 26%, 59% and 19% of the recruited patients, respectively. APOA5 -1131T>C and c.553G>T were significantly associated with high pre-HAART TG while APOE 2198C>T was correlated with high TG at baseline and/or a rise 2-3 years following HAART initiation. Poor CD4 achievement, defined as the highest CD4 count <350/μL and a net gain of <100/μL, was associated with a low CD4 count ≤200/μL at baseline and a rise of TC beyond 5.17 mmol/L following HAART with or without the use of antilipid agents. Conversely, satisfactory CD4 achievement was associated with APOC3 3238GG genotype. Applying a linear generalised estimating equation, APOA5 -1131T>C was shown to be a predictor of a weaker temporal trend for CD4 response in the presence of a low baseline CD4≤200/μL.

CONCLUSIONS

Dyslipidaemia plays a predictive role in impacting immunological recovery following HAART, which could be partly explained by the APO gene SNP.

A pharmacist’s role in the individualization of treatment of HIV patients

The pharmacological treatment of HIV is complex and varies considerably among patients, as does the response of patients to therapy, requiring treatment plans that are closely tailored to individual needs. Pharmacists can take an active role in individualizing care by employing their knowledge of pharmacokinetics and pharmacogenetics and by interacting directly with patients in counseling sessions. These strategies promote the following: maintenance of plasma concentrations of antiretroviral agents within therapeutic ranges, prediction of pharmacological response of patients with certain genetic characteristics, and clinical control of HIV through the correct use of antiretroviral treatments. Together, these strategies can be used to tailor antiretroviral therapy to individual patients, thus improving treatment efficacy and safety.

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.

Polymorphisms in LPL, CETP, and HL protect HIV-infected patients from atherogenic dyslipidemia in an allele-dose-dependent manner

HIV-infected patients treated with highly active antiretroviral therapy (HAART) may be predisposed to a lipid profile, associated with increased cardiovascular risk, derived from having high triglycerides (TG) and low high-density lipoprotein cholesterol (HDLc) levels. We propose that genetic variability leaves some HIV-infected patients more predisposed to this lipid profile than others. We performed a cross-sectional, observational study including 321 antiretroviral-treated HIV-infected patients classified as normolipidemic (n=173) or presenting with high TG (≥1.7 mmol/liter) and low HDLc [<1.02 (men) or 1.28 mmol/liter (women)] (n=148) to investigate the impact of 13 polymorphisms of 9 genes affecting lipid metabolism (APOA5, APOC3, LPL, CETP, HL, MTP, APOE, LRP5, and VLDLR genes). The polymorphism rs328 in LPL was 40% significantly more frequent in normolipidemics (p=0.018), and in the same group, polymorphisms rs708272 in CETP and rs1800588 in HL were 10% significantly more frequent (p=0.037 for both polymorphisms). Patients who presented a combination of one to six alleles from these polymorphisms had 10% increased HDLc levels [1.13 (0.40) vs. 1.24 (0.23) mmol/liter, p=0.002] and a trend toward lower triglycerides [2.23 (2.34) vs. 1.89 (1.24) mmol/liter] and lower remnant-like particle cholesterol (RLPc) [16.41 (11.42) vs. 12.99 (11.69) mmol/liter]. This effect was dependent on the number of protective alleles and independent of the regimen administered. Polymorphisms in LPL, CETP, and HL protect HIV-infected patients from developing the dyslipidemia derived from high TG and low HDLc levels in a dose-dependent manner.

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.

Pharmacogenetics as a tool to tailor antiretroviral therapy: A review

Highly active antiretroviral therapy (HAART) has substantially changed human immunodeficiency virus (HIV) infection from an inexorably fatal condition into a chronic disease with a longer life expectancy. This means that HIV patients should receive antiretroviral drugs lifelong, and the problems concerning with a chronic treatment (tolerability, side effects, adherence to treatment) have now become dominant. In this context, strategies for the treatment personalization have taken a central role in optimizing the therapeutic response and prevention of adverse drug reactions. In this setting, the study of pharmacogenetics features could be a very useful tool in clinical practice; moreover, nowadays the study of genetic profiles allows optimizations in the therapeutic management of People Living With HIV (PLWH) through the use of test introduced into clinical practice and approved by international guidelines for the adverse effects prevention such as the genetic test HLA-B*5701 to detect hypersensitivity to Abacavir. For other tests further studies are needed: CYP2B6 516 G > T testing may be able to identify patients at higher risk of Central Nervous System side effects following standard dosing of Efavirenz, UGT1A1*28 testing before initiation of antiretroviral therapy containing Atazanavir may aid in identifying individuals at risk of hyperbilirubinaemia. Pharmacogenetics represents a ​​research area with great growth potential which may be useful to guide the rational use of antiretrovirals.

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.

Dual antiviral therapy for HIV and hepatitis C - drug interactions and side effects

INTRODUCTION

Roughly 20% of HIV-positive persons worldwide are coinfected with hepatitis C virus (HCV). The recent advent of direct-acting antivirals (DAA) that cure most hepatitis C patients has attracted much attention. Knowledge on drug interactions between DAA and antiretrovirals (ARV) may allow maximizing antiviral efficacy while minimizing drug-related toxicities.

AREAS COVERED

We review the most frequent side effects and clinically significant drug interactions between DAA and ARV. We further discuss how they can be prevented and managed in HIV/HCV-coinfected patients.

EXPERT OPINION

The safety profile of current DAA and the most recently approved ARV is quite favorable. Interactions between DAA and ARV could be frequent in clinical practice. The most common drug interactions affect drug metabolism by inducing or inhibiting the cytochrome P450 system, leading to abnormal drug exposures. Throughout this mechanism HCV and HIV protease inhibitors interact, especially when co-formulated with ritonavir as a pharmacoenhancer, and non-nucleoside HCV and HIV polymerase inhibitors. In contrast, HIV and HCV nucleos(t)ide polymerase inhibitors, and most HCV NS5A inhibitors (i.e., ledipasvir) and HIV integrase inhibitors (i.e., dolutegravir), do not or only marginally affect CYP450, and therefore are free of significant drug interactions. Exposure to HIV and HCV nucleos(t)ide analogues (i.e., tenofovir and sofosbuvir, respectively) is subject to induction/inhibition of drug transporters (i.e., P-glycoprotein).

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.

Role of 3 lipoprotein lipase variants in triglycerides in children receiving highly active antiretroviral therapy

BACKGROUND

Lipoprotein lipase is a key enzyme in lipid metabolism, especially for plasma triglycerides (TGs). Genetic variants have been associated with lipid levels in healthy individuals, cardiovascular disease, obesity and diabetes. Our aim was to evaluate the influence of 3 polymorphisms: Hind III, Pvu II and S447X in plasma TG levels in human immunodeficiency virus-1-infected children under highly active antiretroviral therapy (HAART).

METHODS

Fifty-two children diagnosed with human immunodeficiency virus-1 between 2005 and 2009 were retrospectively selected with at least 1 plasma TG level assessment. TG levels were examined before and after 1 year of HAART. Hypertriglyceridemia was defined as TG > 150 mg/dL. Hind III (H+/H-), Pvu II (P+/P-) and S447X (S/X) were determined by polymerase chain reaction and restricted fragment length polymorphism. The Wilcoxon sum-rank test was used to compare median plasma TG among groups. Also, allelic frequencies were estimated for these variants in an Argentinean population.

RESULTS

Allelic frequencies for human immunodeficiency virus-1-infected children were: H-, 0.21; P-, 0.53; and X, 0.05 with no significant differences to controls. After 1 year of HAART, median TG levels were significantly lower in P-/P- (98.5 mg/dL) when compared with P+/P+ (180 mg/dL) (P = 0.039). The presence of the P- allele was associated with an 11-fold lower risk of hypertriglyceridemia. Hind III and S447X were not associated with TG at the selected time points.

CONCLUSIONS

Our findings suggest a protective effect of lipoprotein lipase polymorphisms against hypertriglyceridemia in children after 1 year of HAART. These results could endorse a prompt nutritional or pharmacological intervention in patients lacking the P- allele.

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.

Association between lipid genetic and immunological status in chronically HIV-infected patients

Introduction

Polymorphisms in some host genes have a significant impact on susceptibility to HIV-1 infection and rate of disease progression [1, 2]. The purpose of the current sub-study was to find out the relationship between polymorphisms in genes involved in the lipid metabolism and the CD4/CD8 T-cell counts.

Methods

Sub-study of a cross-sectional, observational study conducted in 468 patients with HIV infection attended at the outpatient clinic to investigate individual genetic predisposition to atherogenic dyslipidemia (AD). All patients were genetically characterized and all polymorphisms were in Hardy–Weinberg equilibrium. Thirteen polymorphisms were selected from nine genes: APOA5 (rs662799 and rs3135506); APOC3 (rs5128 and rs4520); LPL (rs328 and rs268); CETP (rs708272); HL (rs1800588); MTP (rs1800591); APOE (rs7412 and rs429358); LRP5 (rs7116604); and VLDLR (rs1454626). Lipid and lipoprotein parameters, CD4 and CD8 T-cell counts and plasma HIV-RNA were determinate. The statistical analysis was performed using SPSS statistical software version 19 (SPSS Inc., Chicago, IL, USA).

Results

We studied 468 HIV-infected patients (men, 77%), with a mean (SD) age of 45.9 (19.7) years. The mean CD4 T-cell count and nadir CD4 was 547 (459) and 193 (159) cells/µL, respectively; 78.7% of participants were virologically suppressed. Patients carrying rs3135506 in the APOA5 gene presented a 9% increase in circulating TG levels (p=0.002) and 10% decrease in HDLc levels (p=0.005). Such association of APOA5 towards dyslipidemia was accompanied by a 21% decrease of the CD4 T-cell count (p=0.024) and a 19% increase in CD8 T-cell count (p=0.002) in carriers of the rare allele in the APOA5 rs662799 polymorphism adjusted by age and gender. Patients carrying the rare allele in rs5128 (APOC3) had a 16% decrease in circulating CD4 T cells (p=0.029); patients carrying rs1800591 (MTP) had a 29% decrease in CD4 T cells and 14% decrease in CD8 T cells (p=0.018 and p=0.008, respectively); patients carrying the rare allele rs1800588 in HL had a 11% increase in CD4 T cells (p=0.043); and carriers of the rs145626 in the VLDLR gene had 10% decrease in CD4 circulating T cells (p=0.013).

Conclusion

Variants in genes involved in the development of AD may also influence the immunological host–virus equilibrium in chronically HIV-infected subjects [2, 3].

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.

Toxicogenetics of lopinavir/ritonavir in HIV-infected European patients

AIMS

We present a genetic association study in 106 European HIV-infected individuals aimed at identifying and confirming polymorphisms that have a significant influence on toxicity derived from treatment with lopinavir/ritonavir (LPV/r).

PATIENTS & METHODS

Genotyping was performed by matrix-assisted laser desorption/ionization-time of flight and KASPar^® (KBiosciences, Hoddesdon, UK); LPV/r plasma concentrations were quantified using HPLC with an UV detection system and the pharmacokinetic parameters were estimated using Bayesian algorithms. Genetic association analysis was performed with PASW Statistics 18 (SPSS Inc., IL, USA) and R for Windows (Microsoft, WA, USA).

RESULTS

Suggestive relationships have been established between lipid plasma levels and total bilirubin and SNPs in CETP, MCP1, ABCC2, LEP and SLCO1B3 genes and between diarrhea and SNPs in IL6 gene.

CONCLUSION

Replication analysis should confirm the novel results obtained in this study prior to its application in the clinical practice to achieve a safer LPV/r-based combined antiretroviral therapy.

Evaluation of the pharmacogenetics of immune recovery in treated HIV-infected patients

INTRODUCTION

Combination antiretroviral therapy has markedly improved the survival rate and quality of life in patients infected with HIV due to the powerful suppressor effect that current antiretroviral drugs have on the viral load. Consequently, the immune system undergoes a substantial qualitative and quantitative improvement; and this leads to an increase in the absolute CD4(+) T-lymphocyte count and the restoration of lost T-cell responses against certain opportunistic pathogens. Unfortunately, not all patients who successfully suppress plasma viremia experience sufficient CD4(+) T-cell gain and these patients, in turn, are associated with worse outcomes. Pharmacogenetic studies have been used to investigate how a patient's genetic predisposition may affect their response to antiretroviral drugs.

AREAS COVERED

This article reviews the investigations that have been published on the association between host genetic determinants of CD4(+) T-cell gain in treated HIV-infected patients. Studies were identified through a PubMed database search. Longitudinal studies into pharmacogenetic association were specifically selected.

EXPERT OPINION

While the possibility of genetic predisposition to HIV therapeutics has potential, most studies provide inconsistent data. Inconsistency is often due to partial genetic evaluation, different categorization of poor immune recovery or due to small numbers of patients evaluated. Currently, studies still belong to the research laboratory stage and more studies are required to improve our understanding.

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.

Genetic markers associated to dyslipidemia in HIV-infected individuals on HAART

This study evaluated the impact of 9 single nucleotide polymorphisms (SNPs) in 6 candidate genes (APOB, APOA5, APOE, APOC3, SCAP, and LDLR) over dyslipidemia in HIV-infected patients on stable antiretroviral therapy (ART) with undetectable viral loads. Blood samples were collected from 614 patients at reference services in the cities of Porto Alegre, Pelotas, and Rio Grande in Brazil. The SNPs were genotyped by conventional polymerase chain reaction (PCR) and real-time PCR. The prevalence of dyslipidemia was particularly high among the protease inhibitors-treated patients (79%). APOE (rs429358 and rs7412) genotypes and APOA5 −1131T>C (rs662799) were associated with plasma triglycerides (TG) and low-density-lipoprotein cholesterol levels (LDL-C). The APOA5 −1131T>C (rs662799) and SCAP 2386A>G (rs12487736) polymorphisms were significantly associated with high-density-lipoprotein cholesterol levels. The mean values of the total cholesterol and LDL-C levels were associated with both the APOB SP Ins/Del (rs17240441) and APOB XbaI (rs693) polymorphisms. In conclusion, our data support the importance of genetic factors in the determination of lipid levels in HIV-infected individuals. Due to the relatively high number of carriers of these risk variants, studies to verify treatment implications of genotyping before HAART initiation may be advisable to guide the selection of an appropriate antiretroviral therapy regimen.

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

OBJECTIVE

The impact of host genetic factors on the incidence of dyslipidemia in antiretroviral-naive HIV patients starting antiretroviral therapy (ART) is not clear. We assessed the role of single nucleotide polymorphisms (SNPs) identified from previous genome-wide association studies adjusting for the contribution of nongenetic factors.

METHODS

We assessed 192 SNPs in an HIV cohort who started ART (1997-2008) including a protease inhibitor or a nonnucleoside reverse transcriptase inhibitor (NNRTI). Patients had fasting plasma lipids, total cholesterol (T-Chol), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C) and triglycerides measured prior to their ART initiation and after 1 year. A logistic regression model was constructed and multiple test was corrected using 10% false discovery rate (FDR). Haplotypes and gene interactions were analysed.

RESULTS

A total of 727 individuals were successfully genotyped (n = 381_PI-group; n = 346_NNRTI-group). Age and hepatitis C virus (HCV) coinfection were associated with increases and decreases in T-Chol and LDL-C (P < 0.01), respectively. Protease inhibitor containing ART showed an unfavourable association with T-Chol (P < 0.01) and triglycerides (P = 7.4E-4) and NNRTI-containing ART was favourably associated with HDL-C (P < 0.01). Moreover, SNPs in apolipoprotein B (APOB) were associated with an increase of LDL-C [rs10495712 (P = 3.18E-4); rs754524 (P = 1.26E-3)]. Six SNPs in three genes showed an association with a favourable effect on HDL-C levels when ART included NNRTI: ABCA1 (rs4149313, P = 2.97E-4), LIPC (rs1800588, P = 2.13E-3; rs473224, P = 3.06E-4; rs261336, P = 2.23E-3) and CETP (rs173539, P = 2.96E-3; rs3764261, P = 1.52E-3). After 10% FDR correction for multiple testing, one and six SNPs displayed significant associations with LDL-C and HDL-C, respectively.

CONCLUSION

In HIV-infected patients staring ART, one SNP in APOB was associated with an increase of LDL-C. SNPs in ABCA1/LIPC/CETP were favourably associated with HDL-C when ART included NNRTI. However, an unfavourable effect on T-Chol and triglyceride levels was observed when ART included protease inhibitor. The risk of hypercholesterolaemia increased with age and decreased with HCV coinfection. These findings might help to individualize the selection of ART.

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.

Hypercholesterolemia is associated with the apolipoprotein C-III (APOC3) genotype in children receiving HAART: an eight-year retrospective study

Polymorphisms in apolipoprotein genes have shown to be predictors of plasma lipid levels in adult cohorts receiving highly active antiretroviral therapy (HAART). Our objective was to confirm the association between the APOC3 genotype and plasma lipid levels in an HIV-1-infected pediatric cohort exposed to HAART. A total of 130 HIV-1-infected children/adolescents that attended a reference center in Argentina were selected for an 8-year longitudinal study with retrospective data collection. Longitudinal measurements of plasma triglycerides, total cholesterol, HDL-C and LDL-C were analyzed under linear or generalized linear mixed models. The contribution of the APOC3 genotype at sites −482, −455 and 3238 to plasma lipid levels prediction was tested after adjusting for potential confounders. Four major APOC3 haplotypes were observed for sites −482/−455/3238, with estimated frequencies of 0.60 (C/T/C), 0.14 (T/C/C), 0.11 (C/C/C), and 0.11 (T/C/G). The APOC3 genotype showed a significant effect only for the prediction of total cholesterol levels (p<0.0001). However, the magnitude of the differences observed was dependent on the drug combination (p = 0.0007) and the drug exposure duration at the time of the plasma lipid measurement (p = 0.0002). A lower risk of hypercholesterolemia was predicted for double and triple heterozygous individuals, mainly at the first few months after the initiation of Ritonavir-boosted protease inhibitor-based regimens. We report for the first time a significant contribution of the genotype to total cholesterol levels in a pediatric cohort under HAART. The genetic determination of APOC3 might have an impact on a large portion of HIV-1-infected children at the time of choosing the treatment regimens or on the counter-measures against the adverse effects of drugs.

Peroxisome proliferator activating receptor alpha and gamma polymorphisms and metabolic abnormalities in HIV-infected patients receiving highly active antiretroviral therapy: the ANRS CO8 APROCO-COPILOTE study

Highly active antiretroviral therapy (HAART) is associated with fat redistribution and metabolic disorders. The present study was undertaken to evaluate the association between peroxisome proliferator activated receptor (PPAR)α and PPARγ polymorphisms, two genes involved in lipid metabolism and adipocyte differentiation, and elements of the metabolic syndrome, lipodystrophy, or carbohydrate metabolism abnormalities in patients receiving HAART. The frequency distribution of rare alleles for PPARα (L162V) and PPARγ (P12A and H449H) was compared using the chi square test in 363 HIV-1-infected patients classified according to the presence or absence of the metabolic syndrome after 48 months of follow-up on their first PI-containing regimen. The P12A rare g allele was present in 12% patients with normal glucose metabolism, 11% patients with impaired glucose tolerance or impaired fasting glucose, and 35% patients with diabetes (p=0.014). The rare g allele for L162V was present in 14% of patients free of hypertriglyceridemia and in 7% patients with hypertriglyceridemia (p=0.04). The rare g allele for L162V was found in 15% of patients free of any sign of lipodystrophy and 8% with at least one sign of lipodystrophy (p=0.04) and the rare t allele for H449H was found in 14% of patients free of any sign of lipodystrophy and 23% of patients with at least one sign of lipodystrophy (p=0.05). There was no convincing association between any polymorphism of PPARα and PPARγ and each individual component of the metabolic syndrome, except for the relationship of the P12A polymorphism with diabetes. Confirmatory studies on a larger number of individuals are needed.

[New strategies in the optimisation of lopinavir/ritonavir doses in human immunodeficiency virus-infected patients]

Lopinavir/ritonavir (LPV/r) has demonstrated virological and immunological efficacy in the combined antiretroviral treatment (cART), in both naïve and experienced patients. Furthermore, LPV/r showed a high barrier to the development of resistance. Although generally well tolerated, adverse gastrointestinal side effects and metabolic disorders are frequent. The different tools used to optimise the cART with this drug combination in the daily clinical practice, emphasising the therapeutic drug monitoring (TDM) of LPV/r and the genetic analysis of the main enzymes responsible for the metabolism and transport, are reviewed. The relationship between phenotype and genotype, established through TDM, could be useful for the physician to improve the clinical management of the HIV infection, due to the possibility of individualising the dose with this drug. Monotherapy is also reviewed as a new strategy used in the simplification of the treatment with this drug, which could increase safety and reduce costs.

Impact of apolipoprotein A5 (APOA5) polymorphisms on serum triglyceride levels in schizophrenic patients under long-term atypical antipsychotic treatment

OBJECTIVES

Schizophrenic patients treated with clozapine or olanzapine often develop hypertriglyceridemia. The apolipoprotein A5 gene (APOA5), which affects VLDL production and lipolysis, has been implicated in the triglyceride (TG) metabolism. This study examined the association of common APOA5 genetic variants and TG levels in chronically institutionalized schizophrenic patients, on a stable dose of atypical antipsychotic (clozapine, olanzapine or risperidone.

METHODS

The TG levels in 466 schizophrenic patients treated with clozapine (n = 182), olanzapine (n = 89) or risperidone (n = 195) were measured. Patients were genotyped for the three APOA5 single nucleotide polymorphisms (SNPs) rs662799 (-1131T > C), rs651821 (3A > G) and rs2266788 (1891T > C).

RESULTS

A gene × drug interaction with TG levels was observed. In single-marker-based analysis, the minor alleles of the two polymorphisms (-1131C and -3G) were observed to be associated with increased TGs in patients treated with risperidone, but not with clozapine or olanzapine. Haplotype analysis further revealed that carriers of the haplotype constructed with the three minor alleles had higher TG levels than those who did not carry this haplotype in patients taking risperidone (CGC((+/+)) vs. = 125.4 ± 59.1 vs. 82.2 ± 65.8, P = 0.015; CGC((-/+ )) vs. CGC((-/-)) = 113.7 ± 80.4 vs. 82.2 ± 65.8, P = 0.012).

CONCLUSIONS

Our findings extend and add new information to the existing data regarding the association between APOA5 and TG regulation during long-term atypical antipsychotic treatment.

Individualization of antiretroviral therapy

Antiretroviral therapy (ART) has evolved considerably over the last three decades. From the early days of monotherapy with high toxicities and pill burdens, through to larger pill burdens and more potent combination therapies, and finally, from 2005 and beyond where we now have the choice of low pill burdens and once-daily therapies. More convenient and less toxic regimens are also becoming available, even in resource-poor settings. An understanding of the individual variation in response to ART, both efficacy and toxicity, has evolved over this time. The strong association of the major histocompatibility class I allele HLA-B*5701 and abacavir hypersensitivity, and its translation and use in routine HIV clinical practice as a predictive marker with 100% negative predictive value, has been a success story and a notable example of the challenges and triumphs in bringing pharmacogenetics to the clinic. In real clinical practice, however, it is going to be the exception rather than the rule that individual biomarkers will definitively guide patient therapy. The need for individualized approaches to ART has been further increased by the importance of non-AIDS comorbidities in HIV clinical practice. In the future, the ideal utilization of the individualized approach to ART will likely consist of a combined approach using a combination of knowledge of drug, virus, and host (pharmacogenetic and pharmacoecologic [factors in the individual’s environment that may be dynamic over time]) information to guide the truly personalized prescription. This review will focus on our knowledge of the pharmacogenetics of the efficacy and toxicity of currently available antiretroviral agents and the current and potential utility of such information and approaches in present and future HIV clinical care.

The effect of polymorphisms in candidate genes on the long-term risk of lipodystrophy and dyslipidemia in HIV-infected white patients starting antiretroviral therapy

We investigated whether polymorphisms in human candidate genes could be associated with a different risk of developing lipodystrophy and dyslipidemia in HIV-infected patients starting combination antiretroviral therapy (cART). Genomic DNA samples from white HIV-1-infected patients were analyzed for seven polymorphisms located in the MDR1, TNF-α, APM1, APOE, and LPL genes. Lipid data were retrospectively collected beginning with the initiation of cART. Lipodystrophy was assessed cross-sectionally and then prospectively. The association with lipodystrophy and National Cholesterol Evaluation Program Adult Treatment Panel III-defined lipid thresholds was analyzed using survival analysis and logistic regression. One-hundred and seventy-four patients were genotyped. In 151 patients assessed for lipodystrophy, MDR1 3435 T homozygosis was associated with a higher hazard (adjusted hazard ratio, aHR, versus CT 0.25; p=0.02) and tumor necrosis factor (TNF)-α 308 G homozygosis with a lower hazard (vs. AA aHR 2.14; p=0.04) of developing trunk fat accumulation after adjusting for gender and initial cART type. The TNF 238 GG genotype was associated with a higher risk of developing low HDL-cholesterol levels (adjusted odd ratio, aOR, 5.91; p=0.01) while patients carrying the LPL S477X mutation were at lower risk of reaching high non-HDL-cholesterol levels (aOR 0.39; p=0.05). The APOEe3/3 genotype patients were at lower risk (aOR 0.26, p=0.015), whereas the adiponectin 276 GT carriers were at higher risk of developing hypertriglyceremia (vs. GG aOR 3.10; p=0.04). Knowledge of the effect of genetic determinants on dyslipidemia and lipodystrophy may prompt the investigation of potential pathogenetic mechanisms and might eventually be used for guiding individualized treatment decisions.

The Relationship Between HIV Infection and Cardiovascular Disease

Over 30 million people are currently living with human immunodeficiency virus (HIV) infection, and over 2 million new infections occur per year. HIV has been found to directly affect vascular biology resulting in an increased risk of cardiovascular disease compared to uninfected persons. Although HIV infection can now be treated effectively with combination antiretroviral medications, significant toxicities such as hyperlipidemia, diabetes, and excess cardiovascular co-morbidity; as well as the potential for significant drug-drug interactions between HIV and cardiovascular medications, present new challenges for the management of persons infected with HIV. We first review basic principles of HIV pathogenesis and treatment and then discuss relevant clinical management strategies that will be useful for cardiologists who might be involved in the care of HIV infected patients.

No relationship between TNF-α genetic variants and combination antiretroviral therapy-related lipodystrophy syndrome in HIV type 1-infected patients: a case-control study and a meta-analysis

Tumor necrosis factor alpha (TNF-α) is thought to be involved in the pathogenic and metabolic events associated with HIV-1 infection. We assessed whether carriage of the TNF-α gene promoter single nucleotide polymorphism (SNP) is associated with lipodystrophy and metabolic derangements in HIV-1-infected patients treated with cART. We also assessed variations in TNF-α receptor plasma levels. The study group comprised 286 HIV-1-infected patients (133 with and 153 without lipodystrophy) and 203 uninfected controls (UC). TNF-α -238G > A, -308G > A, and -863 C > A SNP were assessed using PCR-RFLPs on white cell DNA. Plasma sTNF-α R1 and R2 levels were measured by ELISA. Student's t test, the χ(2) test, Pearson correlations, and the logistic regression test were performed for statistical analysis. The TNF-α -308G > A SNP was significantly associated with lipodystrophy in the univariate analysis (p = 0.04). This association, however, was no longer significant in the multivariate analysis. A meta-analysis of the published literature and our own data, which included 284 patients with lipodystrophy and 338 without lipodystrophy, showed that there was no relationship between the TNF-α -238G > A and -308G > A SNP and lipodystrophy (p > 0.05 for all comparisons). HIV-1-infected patients had greater sTNF-α R2 plasma levels than UC (p = 0.001) whereas sTNF-α R1 and R2 levels were not significantly different in both the HIV-1-infected cohorts, lipodystrophy vs. nonlipodystrophy (p = NS). In our cohort of white Spaniards the TNF-α -238G > A, -308G > A, and -863C > A SNP were not associated with lipodystrophy in HIV-1-infected patients treated with cART. This finding was replicated in a meta-analysis of the published data, which showed no associations between the TNF-α -238G > A and -308G > A SNP and lipodystrophy. In HIV-1-infected patients under cART there is a systemic overproduction of sTNF-α R2, which is unrelated to the presence of lipodystrophy.

European mitochondrial DNA haplogroups and metabolic changes during antiretroviral therapy in AIDS Clinical Trials Group Study A5142

BACKGROUND

Mitochondrial DNA (mtDNA) influences metabolic diseases and perhaps antiretroviral therapy (ART) complications. We explored associations between European mtDNA haplogroups and metabolic changes among A5142 participants.

METHODS

Seven hundred and fifty-seven ART-naive patients were randomized to one of three class-sparing ART regimens including efavirenz and/or lopinavir/ritonavir with or without nucleoside reverse transcriptase inhibitors (NRTIs). Nonrandomized NRTIs included stavudine, tenofovir, or zidovudine, each with lamivudine. Fasting lipid profiles and whole-body dual-energy X-ray absorptiometry (DEXA) were performed. Nine European mtDNA haplogroups were determined for 231 self-identified non-Hispanic white individuals. Metabolic changes from baseline to 96 weeks were analyzed by haplogroup.

RESULTS

Median age was 39 years, 9% were women, and 37, 32, and 30 were randomized to NRTI-containing regimens with either efavirenz or lopinavir/ritonavir, and an NRTI-sparing regimen, respectively. Among NRTI-containing regimens, 51% included zidovudine, 28% tenofovir, and 21% stavudine. Compared with other haplogroups, mtDNA haplogroup I (N = 10) had higher baseline non-HDL cholesterol [160 mg/dl (interquartile range 137-171) vs. 120 mg/dl (104-136); P = 0.005], a decrease in non-HDL cholesterol over 96 weeks [-14% (-20 to 6) vs. +25% (8 to 51); P < 0.001], tended to have more baseline extremity fat, and had more extremity fat loss by DEXA [-13% (-13 to 12) vs. +9% (-13 to 26); P = 0.08] and lipoatrophy (50 vs. 20%; P = 0.04). Haplogroup W (N = 5; all randomized to NRTI-sparing regimens) had the greatest increase in extremity fat [+35.5% (26.8 to 54.9); P = 0.02].

CONCLUSIONS

Lipids and extremity fat were associated with European mtDNA haplogroups in this HIV-infected population. These preliminary results suggest that mitochondrial genomics may influence metabolic parameters before and during ART.

Association of pharmacogenetic markers with premature discontinuation of first-line anti-HIV therapy: an observational cohort study

BACKGROUND

Poor tolerance and adverse drug reactions are main reasons for discontinuation of antiretroviral therapy (ART). Identifying predictors of ART discontinuation is a priority in HIV care.

METHODS

A genetic association study in an observational cohort to evaluate the association of pharmacogenetic markers with time to treatment discontinuation during the first year of ART. Analysis included 577 treatment-naive individuals initiating tenofovir (n = 500) or abacavir (n = 77), with efavirenz (n = 272), lopinavir/ritonavir (n = 184), or atazanavir/ritonavir (n = 121). Genotyping included 23 genetic markers in 15 genes associated with toxicity or pharmacokinetics of the study medication. Rates of ART discontinuation between groups with and without genetic risk markers were assessed by survival analysis using Cox regression models.

RESULTS

During the first year of ART, 190 individuals (33%) stopped 1 or more drugs. For efavirenz and atazanavir, individuals with genetic risk markers experienced higher discontinuation rates than individuals without (71.15% vs 28.10%, and 62.5% vs 14.6%, respectively). The efavirenz discontinuation hazard ratio (HR) was 3.14 (95% confidence interval (CI): 1.35-7.33, P = .008). The atazanavir discontinuation HR was 9.13 (95% CI: 3.38-24.69, P < .0001).

CONCLUSIONS

Several pharmacogenetic markers identify individuals at risk for early treatment discontinuation. These markers should be considered for validation in the clinical setting.

Dyslipidemia in HIV-infected individuals: from pharmacogenetics to pharmacogenomics

HIV-infected individuals may have accelerated atherogenesis and an increased risk for premature coronary artery disease. Dyslipidemia represents a key pro-atherogenic mechanism. In HIV-infected patients, dyslipidemia is typically attributed to the adverse effects of antiretroviral therapy. Nine recent genome-wide association studies have afforded a comprehensive, unbiased inventory of common SNPs at 36 genetic loci that are reproducibly associated with dyslipidemia in the general population. Genome-wide association study-validated SNPs have now been demonstrated to contribute to dyslipidemia in the setting of HIV infection and antiretroviral therapy. In a Swiss HIV-infected study population, a similar proportion of serum lipid variability was explained by antiretroviral therapy and by genetic background. In the individual patient, both antiretroviral therapy and the cumulative effect of SNPs contribute to the risk of high low-density lipoprotein cholesterol, low high-density lipoprotein cholesterol and hypertriglyceridemia. Genetic variants presumably contribute to additional major metabolic complications in HIV-infected individuals, including diabetes mellitus and coronary artery disease. In an effort to explain an increasing proportion of the heritability of complex metabolic traits, ongoing large-scale gene resequencing studies are focusing on the effects of rare SNPs and structural genetic variants.

Pharmacogenetics of antiretroviral agents

PURPOSE OF REVIEW

The past year has seen the first whole genome association study for determinants of host control of HIV, as well as a number of hypothesis-driven candidate gene studies defining determinants of pharmacokinetics and toxicity of antiretroviral drugs. This review summarizes some of these findings, but it must be noted that the field is moving with unprecedented speed.

RECENT FINDINGS

A number of novel polymorphisms have been reported in the CYP2B6 locus that influence pharmacokinetics of non-nucleoside reverse transcriptase inhibitors. Among these are some novel nonsynonomous single nucleotide polymorphisms such as 983T > C (CYP2B6 18) and 499C > G (CYP2B6 26), as well as a partial deletion (CYP2B6 29). In addition, the concept of dose reduction according to CYP2B6 genotype has now been tested with some promising but preliminary results. Some other important advances in our knowledge have also been made, such as the association of TA repeats in the UGT1A1 regulatory region (UGT1A1 28) with atazanavir-related hyperbilirubinaemia and the association of ABCC2 and ABCC4 single nucleotide polymorphisms with tenofovir-associated renal toxicity.

SUMMARY

Treatment response to antiretrovirals is governed by genetic and environmental factors as well as adherence to therapy. Variability exists within pharmacological, immune and viral genes, and future studies must co-ordinate these issues.

Contribution of genome-wide significant single-nucleotide polymorphisms and antiretroviral therapy to dyslipidemia in HIV-infected individuals: a longitudinal study

BACKGROUND

HIV-infected individuals have an increased risk of myocardial infarction. Antiretroviral therapy (ART) is regarded as a major determinant of dyslipidemia in HIV-infected individuals. Previous genetic studies have been limited by the validity of the single-nucleotide polymorphisms (SNPs) interrogated and by cross-sectional design. Recent genome-wide association studies have reliably associated common SNPs to dyslipidemia in the general population.

METHODS AND RESULTS

We validated the contribution of 42 SNPs (33 identified in genome-wide association studies and 9 previously reported SNPs not included in genome-wide association study chips) and of longitudinally measured key nongenetic variables (ART, underlying conditions, sex, age, ethnicity, and HIV disease parameters) to dyslipidemia in 745 HIV-infected study participants (n=34 565 lipid measurements; median follow-up, 7.6 years). The relative impact of SNPs and ART to lipid variation in the study population and their cumulative influence on sustained dyslipidemia at the level of the individual were calculated. SNPs were associated with lipid changes consistent with genome-wide association study estimates. SNPs explained up to 7.6% (non-high-density lipoprotein cholesterol), 6.2% (high-density lipoprotein cholesterol), and 6.8% (triglycerides) of lipid variation; ART explained 3.9% (non-high-density lipoprotein cholesterol), 1.5% (high-density lipoprotein cholesterol), and 6.2% (triglycerides). An individual with the most dyslipidemic antiretroviral and genetic background had an approximately 3- to 5-fold increased risk of sustained dyslipidemia compared with an individual with the least dyslipidemic therapy and genetic background.

CONCLUSIONS

In the HIV-infected population treated with ART, the weight of the contribution of common SNPs and ART to dyslipidemia was similar. When selecting an ART regimen, genetic information should be considered in addition to the dyslipidemic effects of ART agents.

Pharmacogenetics of antiretrovirals

The introduction of highly active antiretroviral therapy (HAART) as standard of care has changed the natural history of HIV infection into a manageable chronic disease requiring long-term antiretroviral (ARV) treatment. However, response to HAART is often limited by the occurrence of toxicity or by the emergence of drug resistance. Antiretroviral treatment is characterized by differing rates of adverse events and responses. Genetic variations between human beings account for a relevant proportion of this variability. A relevant number of associations between human genetic variants and predisposition to adverse events have been described and for some antiretroviral drugs a clear and casual genotype-phenotype correlation has already been established. The strong association between abacavir hypersensitivity reaction and HLA-B*5701 has been demonstrated in both observational and blinded randomized clinical trials in racially diverse populations and represents the best example of the clinical utility of pharmacogenetic screening in HIV medicine. Genotyping for HLA-B*5701 before prescribing an abacavir containing regimen has been introduced into routine clinical practice as the standard of care for all patients. Other well-established associations include CYP2B6 alleles and efavirenz central nervous system side effects, UGT1A1 alleles and atazanavir-associated hyperbilirubinemia and HLA class II allele HLA-DRB*0101 and nevirapine-associated hypersensitivity. Despite genetic associations having been described for peripheral neuropathy, lipodystrophy, hyperlipidaemia, pancreatitis and renal proximal tubulopathy, numerous barriers exist to the successful introduction of widespread genetic testing to the clinic. Future prospects point in the direction of individualization of antiretroviral therapy through insights from host genetics. The present paper is aimed to provide a comprehensive review of the published literature and to summarize the state of research in this area. This article forms part of a special issue of Antiviral Research marking the 25th anniversary of antiretroviral drug discovery and development, Vol 85, issue 1, 2010.

Cardiovascular disease and HIV infection: host, virus, or drugs?

PURPOSE OF REVIEW

With effective antiretroviral therapy, cardiovascular disease has gained importance as a cause of morbidity and mortality in HIV-infected persons. We review the risk of cardiovascular disease in HIV-infected persons compared with that in uninfected persons and discuss the relative contributions of host, HIV, and antiretroviral therapy in the light of current knowledge.

RECENT FINDINGS

The incidence of cardiovascular disease in HIV-infected patients receiving antiretroviral therapy is low. However, the risk of cardiovascular disease increased compared with that in uninfected persons. This fact is substantially due to a higher prevalence of underlying traditional cardiovascular risk factors that are mostly host dependent. HIV may additionally contribute both directly through immune activation and inflammation, and indirectly through immunodeficiency. In a more modest way than that of HIV infection, the type of antiretroviral therapy may also contribute through its impact on metabolic and body fat parameters, and possibly through other factors that are currently unclear.

SUMMARY

Prevention of cardiovascular disease in HIV-infected patients should be standard of care. Traditional risk factors should be investigated and aggressively treated when possible. Antiretroviral therapy should be initiated earlier in patients with high cardiovascular risk. From a purely cardiovascular perspective, the benefits of antiretroviral therapy clearly outweigh any potential risk.

Serum lipid profiles among patients initiating ritonavir-boosted atazanavir versus efavirenz-based regimens

BACKGROUND

Antiretrovirals used to treat HIV-infected patients have the potential to adversely affect serum lipid profiles and increase the risk of cardiovascular disease which is an emerging concern among HIV-infected patients. Since boosted atazanavir and efavirenz are both considered preferred antiretrovirals a head to head comparison of their effects on serum lipids is needed.

AIM

The primary objective of the study was to compare the effects of atazanavir (boosted and unboosted) and efavirenz based regimens on serum lipid profiles.

STUDY DESIGN

Prospective cohort study nested within three ongoing cohorts of HIV-infected individuals.

STUDY POPULATION AND METHODS

Participants initiating either atazanavir or efavirenz based regimens with documented pre- and post-initiation lipid values. Multivariate linear regression was conducted to estimate adjusted mean differences between treatment groups for high density lipoprotein cholesterol (HDL-c), non-HDL-c, and log total cholesterol (TC) to HDL-c ratio outcomes; log-linear regression models were used to estimate differences in prevalence of low HDL-c and desirable TC.

RESULTS

The final study population was comprised of 380 efavirenz and 281 atazanavir initiators. Both atazanavir and efavirenz users had increases in serum HDL-c and decreases in TC/HDL ratio. In comparison to individuals initiating efavirenz, boosted atazanavir users on average had lower HDL-c (-4.12 mg/dl, p < 0.001) and non HDL-c (-5.75 mg/dl, p < 0.01), but similar declines in TC/HDL ratio.

CONCLUSION

Both efavirenz and atazanavir-based regimens (boosted and unboosted) resulted in similar beneficial declines in the TC/HDL ratio.

The impact of pharmacogenetics on HIV therapy

Summary

The use of highly active antiretroviral therapy in the treatment of HIV infection has resulted in significant reductions in mortality and morbidity worldwide. However, there is considerable interindividual variability in patient outcomes in terms of drug disposition, drug efficacy and adverse events. The basis of these differences is multifactorial, but host genetics are believed to play a significant part. To date, most attempts to explain this variability have focused on isolated single nucleotide polymorphisms. The most exciting development to date is the discovery of human leukocyte antigen subtype B*5701 (HLA B*5701) as a strong predictor of the abacavir hypersensitivity reaction. There is a gradual move away from single candidate gene analyses towards a high throughput whole genome approach. These studies must be performed on well characterized cohorts and reported associations must be validated in independent, ethnically diverse populations.

[Toxicogenetics of antiretroviral treatment (1): lipodystrophy, metabolic perturbations and atherosclerosis]

Among the adverse effects attributed to antiretroviral therapy, one of the most striking is probably the appearance of the lipodystrophy syndrome and its associated metabolic derangements, given its potential long-term effect as a cardiovascular risk factor. Since not all patients who receive antiretroviral drugs experience these adverse effects, a host genetic predisposition has been postulated. However, currently available data on this issue is inconclusive and preliminary. It has been consistently demonstrated that polymorphisms in the genes that encode for apolipoproteins A5, C3 and E, for the cholesterol ester transporter proteins (CETP), and in the ATP binding cassette type A1 (ABCA1) influence the development of dyslipidemia in patients treated with antiretroviral drugs, particularly if the therapeutic regimen includes protease inhibitors. Data on the effect of polymorphisms in the sterol regulatory ester binding protein type 1 (SREBP1) are inconsistent. The effect of mitochondrial DNA mutations on the risk of lipodystrophy has been assessed, with inconclusive data. No polymorphisms in the lamin A gene have been detected. Investigations have assessed the effect of diverse polymorphisms in the genes that encode for several proinflammatory cytokines such as tumour necrosis factor alpha (TNF-alpha), interleukin-1-beta (IL-1beta) and interleukin-6 (IL-6). The results show inconsistent data in the case of TNF-alpha, no association in the case of IL-6, and preliminary positive associations in IL-1beta. In contrast, polymorphisms in the genes encoding for stromal derived factor 1 (SDF-1) and for monocyte chemoattractant protein 1 (MCP-1) have been shown to influence the development of subclinical atherosclerosis in HIV-1-infected patients treated with antiretroviral drugs.