HAART-associated dyslipidemia varies by biogeographical ancestry in the multicenter AIDS cohort study

Long-term intra- and inter-individual biological variation of serum lipid of HIV-infected and uninfected men participating in the Los Angeles Multi-Center AIDS Cohort Study (MACS)

BACKGROUND

To assess the long-term biological coefficient of variation within individuals (CV_I) and between individuals (CV_G), effect of aging and cholesterol lowering drugs on blood levels of lipids in HIV-1-infected and -uninfected men.

METHODS

Bloods were analyzed every six months over 17 years for total cholesterol (TC), triglycerides (TGs), high-density lipoprotein cholesterol (HDL-C) and low-density lipoprotein cholesterol (LDL-C) in 140 HIV-uninfected (38-66 years old) and 90 HIV-treated infected (48-64 years old) white Caucasian men to examine CV_I, CV_G, and the effect of cholesterol lowering drugs (CLDs) on lipid levels, and estimated changes per year of biomarkers.

RESULTS

With exception of HDL-C, the long term CV_I compared with CV_G were higher for serum levels of TC, TGs, and LDL-C in both HIV-1 infected and uninfected men not taking CLDs. Excluding results of TGs in HIV positive men, the CV_I compared with CV_G were lower for serum levels of TC, HDL-C, and LDL-C in both groups not taking CLDs. There were significant (p < 0.05) differences in the median serum values of lipid biomarkers among 77 HIV negative men taking and 63 not taking CLDs. Also, with exception of HDL, there were significant (p < 0.05) differences in the median values of TC, TGs and LDL-C among 28 HIV positive men taking or not taking CLDs.

CONCLUSION

Long term CV_I and CV_G of biomarkers will be useful for monitoring antiviral therapy side effects on lipid profiles in HIV-infected men. CV_I of HIV-infected men for TC, TGs, HDL, LDL were higher significantly than CV_I of HIV-uninfected men. Interestingly the long term CV_I were higher than CV_G for the men, who were on CLDs compared to men not on CLDs. The long-term pattern of CV_I and CV_G of lipid markers in both HIV-infected and uninfected men on CLDs differed from their short-term pattern.

Genetically determined ancestry is more informative than self-reported race in HIV-infected and -exposed children

The Pediatric HIV/AIDS Cohort Study (PHACS), the largest ongoing longitudinal study of perinatal HIV-infected (PHIV) and HIV-exposed, uninfected (PHEU) children in the United States, comprises the Surveillance Monitoring of Antiretroviral Therapy [ART] Toxicities (SMARTT) Study in PHEU children and the Adolescent Master Protocol (AMP) that includes PHIV and PHEU children ≥7 years. Although race/ethnicity is often used to assess health outcomes, this approach remains controversial and may fail to accurately reflect the backgrounds of ancestry-diverse populations as represented in the PHACS participants.In this study, we compared genetically determined ancestry (GDA) and self-reported race/ethnicity (SRR) in the PHACS cohort. GDA was estimated using a highly discriminative panel of 41 single nucleotide polymorphisms and compared to SRR. Because SRR was similar between the PHIV and PHEU, and between the AMP and SMARTT cohorts, data for all unique 1958 participants were combined.According to SRR, 63% of study participants identified as Black/African-American, 27% White, and 34% Hispanic. Using the highest percentage of ancestry/ethnicity to identify GDA, 9.5% of subjects were placed in the incorrect superpopulation based on SRR. When ≥50% or ≥75% GDA of a given superpopulation was required, 12% and 25%, respectively, of subjects were placed in the incorrect superpopulation based on SRR, and the percent of subjects classified as multiracial increased. Of 126 participants with unidentified SRR, 71% were genetically identified as Eurasian.GDA provides a more robust assessment of race/ethnicity when compared to self-report, and study participants with unidentified SRR could be assigned GDA using genetic markers. In addition, identification of continental ancestry removes the taxonomic identification of race as a variable when identifying risk for clinical outcomes.

Associations of Genetically Determined Continental Ancestry With CD4+ Count and Plasma HIV-1 RNA Beyond Self-Reported Race and Ethnicity

BACKGROUND

Ancestry informative markers (AIMs) measure genetic admixtures within an individual beyond self-reported racial/ethnic (SRR) groups. Here, we used genetically determined ancestry (GDA) across SRR groups and examine associations between GDA and HIV-1 RNA and CD4 counts in HIV-positive children in the United States.

METHODS

Forty-one AIMs, developed to distinguish 7 continental regions, were detected by real-time PCR in 994 HIV-positive, antiretroviral naive children. GDA was estimated comparing each individual's genotypes to allele frequencies found in a large set of reference individuals originating from global populations using STRUCTURE. The means of GDA were calculated for each category of SRR. Linear regression was used to model GDA on CD4 count and log10 RNA, adjusting for SRR and age.

RESULTS

Subjects were 61% black, 25% Hispanic, 13% white, and 1.3% Unknown. The mean age was 2.3 years (45% male), mean CD4 count of 981 cells per cubic millimeter, and mean log10 RNA of 5.11. Marked heterogeneity was found for all SRR groups with high admixture for Hispanics. In adjusted linear regression models, subjects with 100% European ancestry were estimated to have 0.33 higher log10 RNA levels (95% CI: 0.03 to 0.62, P = 0.028) and 253 CD4 cells per cubic millimeter lower (95% CI: -517 to 11, P = 0.06) in CD4 count, compared to subjects with 100% African ancestry.

CONCLUSION

Marked continental admixture was found among this cohort of HIV-infected children from the United States. GDA contributed to differences in RNA and CD4 counts beyond SRR and should be considered when outcomes associated with HIV infection are likely to have a genetic component.

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.

Effects of raltegravir combined with tenofovir/emtricitabine on body shape, bone density, and lipids in African-Americans initiating HIV therapy

BACKGROUND

Raltegravir (RAL) plus tenofovir/emtricitabine (TDF/FTC) is a recommended initial antiretroviral regimen. A substantial proportion of persons diagnosed with HIV infection and starting antiretrovirals in the U.S. are African-American (AA); however, the effects of this regimen on metabolic parameters have largely been studied in white patients.

METHODS

Single-arm, open-label study of untreated AA HIV-infected patients administered RAL with TDF/FTC for 104 weeks. Changes in fasting lipids, insulin resistance, visceral adipose tissue (VAT), abdominal subcutaneous adipose tissue (SAT), limb and trunk fat, and bone mineral density (BMD) were assessed at weeks 56 and 104.

RESULTS

Thirty (85% men) participants were included. Median entry characteristics included age of 38 years, CD4 323 cells/mm3, HIV RNA level 29,245 copies/ml, and body mass index 28.1 kg/m2. At 56 and 104 weeks, significant increases in VAT, trunk fat, limb fat, and overall fat were observed. Bone mineral density decreased by 1.5% by week 104.There were no significant changes in non-HDL-cholesterol, fasting triglycerides, or insulin resistance. A median CD4 cell count increase of 318 cells/mm3 (IQR 179, 403; full range 40, 749) (P<0.001) was observed. Assuming missing=failure, 78 and 70% had HIV RNA levels<40 copies/ml at weeks 56 and 104, respectively. There were no treatment-related discontinuations and no new antiretroviral resistance mutations were detected.

CONCLUSIONS

In this cohort of AAs, initiation of RAL with TDF/FTC was associated with significant general increases in fat. Significant changes in lipids or insulin resistance were not observed and there was a small decline in BMD. Therapy was well tolerated and effective. These results are consistent with findings of studies of initial antiretroviral therapy in racially diverse cohorts and inform treatment selection for AA patients starting therapy for HIV infection.

Association of Toll-like receptor polymorphisms with HIV status in North Americans

Single nucleotide polymorphisms (SNPs) in toll-like receptor (TLR) genes TLR2-4 and TLR7-9, but not in TLR1 and TLR6, have been previously evaluated regarding HIV acquisition and disease progression in various populations, most of which were European. In the present study, we examined associations between a total of 41 SNPs in 8 TLR genes (TLR1-4, TLR6-9) and HIV status in North American subjects (total n = 276 [Caucasian, n = 102; African American, n = 150; other, n = 24]). Stratification of the data by self-identified race revealed that a total of 9 SNPs in TLR1, TLR4, TLR6, and TLR8 in Caucasians, and 2 other SNPs, one each in TLR4 and TLR8, in African Americans were significantly associated with HIV status at P < 0.05. Concordant with the odds ratios of these SNPs, significant differences were observed in the SNP allele frequencies between HIV+ and HIV− subjects. Finally, in Caucasians, certain haplotypes of single (TLR1, TLR4) and heterodimer (TLR2_TLR6) genes may be inferred as “susceptible” or “protective”. Our study provides in-depth insight into the associations between TLR variants, particularly TLR1 and TLR6, and HIV status in North Americans, and suggests that these associations may be race-specific.

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.

Metabolic syndrome, diabetes, and cardiovascular risk in HIV

HIV infection and its treatment have been associated with adipose tissue changes and disorders of glucose and lipid metabolism. The proportion of HIV-infected adults over the age of 50 is also growing placing HIV-infected adults at particular risk for metabolic perturbations and cardiovascular disease. The metabolic syndrome in HIV-infected adults has been increasingly studied but whether HIV is associated with greater risk remains unclear, likely because of the interplay of host, viral and antiretroviral factors that are associated with the components of the metabolic syndrome. The relationship between HIV and diabetes mellitus (DM) risk has also been debated. While the Framingham Risk Score is a well-accepted measure of 10-year cardiovascular risk in the general population, it may not accurately predict risk in the HIV setting due to HIV-related factors such as inflammation that are not accounted for. We summarize the recent literature on metabolic syndrome, DM, and cardiovascular risk in HIV-infected adults.

African ancestry influences CCR5 -2459G>A genotype-associated virologic success of highly active antiretroviral therapy

INTRODUCTION

In a North American, HIV-positive, highly active antiretroviral therapy (HAART)-treated, adherent cohort of self-identified white and black patients, we previously observed that chemokine (C-C motif) receptor 5 (CCR5) -2459G>A genotype had a strong association with time to achieve virologic success (TVLS) in black but not in white patients.

METHODS

Using 128 genome-wide ancestry informative markers, we performed a quantitative assessment of ancestry in these patients (n = 310) to determine (1) whether CCR5 -2459G>A genotype is still associated with TVLS of HAART when ancestry, not self-identified race, is considered and (2) whether this association is influenced by varying African ancestry.

RESULTS

We found that the interaction between CCR5 -2459G>A genotype and African ancestry (≤ 0.125 vs. ≥ 0.425 and <0.71 vs. ≥ 0.71) was significantly associated with TVLS (GG compared with AA, P = 0.044 and 0.018, respectively). Furthermore, the association between CCR5 -2459G>A genotype and TVLS was stronger in patients with African ancestry ≥ 0.71 than in patients with African ancestry ≥ 0.452, in both Kaplan-Meier (log-rank P = 0.039 and 0.057, respectively, for AA, GA, and GG) and Cox proportional hazards regression (relative hazard for GG compared with AA 2.59 [95% confidence interval: 1.27 to 5.22; P = 0.01] and 2.26 [95% confidence interval: 1.18 to 4.32; P = 0.01], respectively) analyses.

CONCLUSIONS

We observed that the association between CCR5 -2459G>A genotype and TVLS of HAART increased with stronger African ancestry. Understanding the genomic mechanisms by which African ancestry influences this association is critical and requires further studies.

Alterations in the gut microbiota associated with HIV-1 infection

Understanding gut microbiota alterations associated with HIV infection and factors that drive these alterations may help explain gut-linked diseases prevalent with HIV. 16S rRNA sequencing of feces from HIV-infected individuals revealed that HIV infection is associated with highly characteristic gut community changes, and antiretroviral therapy does not consistently restore the microbiota to an HIV-negative state. Despite the chronic gut inflammation characteristic of HIV infection, the associated microbiota showed limited similarity with other inflammatory states and instead showed increased, rather than decreased, diversity. Meta-analysis revealed that the microbiota of HIV-infected individuals in the U.S. was most similar to a Prevotella-rich community composition typically observed in healthy individuals in agrarian cultures of Malawi and Venezuela and related to that of U.S. individuals with carbohydrate-rich, protein- and fat-poor diets. By evaluating innate and adaptive immune responses to lysates from bacteria that differ with HIV, we explore the functional drivers of these compositional differences.