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1.  Underlying genetic structure impacts the association between CYP2B6 polymorphisms and response to efavirenz and nevirapine 
AIDS (London, England)  2012;26(16):2097-2106.
Objective
CYP2B6 variation predicts pharmacokinetic characteristics of its substrates. Consideration for underlying genetic structure is critical to protect against spurious associations with the highly polymorphic CYP2B6 gene.
Design
The effect of CYP2B6 variation on response to its substrates, nonnucleoside reverse transcriptase inhibitors (NNRTIs), was explored in the Women's Interagency HIV Study.
Methods
Five putative functional polymorphisms were tested for associations with virologic suppression within one year after NNRTI initiation in women naïve to antiretroviral agents (n=91). Principal components (PCs) were generated to control for population substructure. Logistic regression was used to test the joint effect of rs3745274 and rs28399499, which together indicate slow, intermediate, and extensive metabolizers.
Results
Rs3745274 was significantly associated with virologic suppression (OR=3.61, 95% CI 1.16-11.22, p trend=0.03); the remaining polymorphisms tested were not significantly associated with response. Women classified as intermediate and slow metabolizers were 2.90 (95% CI 0.79-12.28) and 13.44 (95% CI 1.66-infinity) times as likely to achieve virologic suppression compared to extensive metabolizers after adjustment for PCs (p trend=0.005). Failure to control for genetic ancestry resulted in substantial confounding of the relationship between the metabolizer phenotype and treatment response.
Conclusion
The CYP2B6 metabolizer phenotype was significantly associated with virologic response to NNRTIs; this relationship would have been masked by simple adjustment for self-reported ethnicity. Given the appreciable genetic heterogeneity that exists within self-reported ethnicity, these results exemplify the importance of characterizing underlying genetic structure in pharmacogenetic studies. Further follow-up of the CYP2B6 metabolizer phenotype is warranted given the potential clinical importance of this finding.
doi:10.1097/QAD.0b013e3283593602
PMCID: PMC3940150  PMID: 22951632
CYP2B6; population substructure; women; NNRTIs; confounding
2.  A Single-Nucleotide Polymorphism in CYP2B6 Leads to >3-Fold Increases in Efavirenz Concentrations in Plasma and Hair Among HIV-Infected Women 
The Journal of Infectious Diseases  2012;206(9):1453-1461.
Background. Efavirenz exhibits marked interindividual variability in plasma levels and toxicities. Prior pharmacogenetic studies usually measure exposure via single plasma levels, examine limited numbers of polymorphisms, and rarely model multiple contributors. We analyzed numerous genetic and nongenetic factors impacting short-term and long-term exposure in a large heterogeneous population of human immunodeficiency virus (HIV)–infected women.
Methods. We performed 24-hour intensive pharmacokinetic studies in 111 women receiving efavirenz under actual-use conditions and calculated the area-under-the-concentration-time curve (AUC) to assess short-term exposure; the efavirenz concentration in hair was measured to estimate long-term exposure. A total of 182 single-nucleotide polymorphisms (SNPs) and 45 haplotypes in 9 genes were analyzed in relationship to exposure by use of multivariate models that included a number of nongenetic factors.
Results. Efavirenz AUCs increased 1.26-fold per doubling of the alanine aminotransferase level and 1.23-fold with orange and/or orange juice consumption. Individuals with the CYP2B6 516TT genotype displayed 3.5-fold increases in AUCs and 3.2-fold increases in hair concentrations, compared with individuals with the TG/GG genotype. Another SNP in CYP2B6 (983TT) and a p-glycoprotein haplotype affected AUCs without substantially altering long-term exposure.
Conclusions. This comprehensive pharmacogenomics study showed that individuals with the CYP2B6 516TT genotype displayed >3-fold increases in both short-term and long-term efavirenz exposure, signifying durable effects. Pharmacogenetic testing combined with monitoring of hair levels may improve efavirenz outcomes and reduce toxicities.
doi:10.1093/infdis/jis508
PMCID: PMC3466997  PMID: 22927450
3.  Absence of reproducibly detectable low-level HIV viremia in highly exposed seronegative men and women. 
AIDS (London, England)  2011;25(5):619-623.
Objective
Transient HIV infections have been invoked to account for the cellular immune responses detected in highly virus-exposed individuals who have remained HIV seronegative. We tested for very low levels of HIV RNA in 524 seronegative plasma samples from 311 highly exposed women and men from 3 longitudinal HIV cohorts.
Design
2073 transcription mediated amplification (TMA) HIV RNA tests were performed for an average of 3.95 TMA assays per plasma sample. Quadruplicate TMA assays, analyzing a total of 2 ml of plasma, provided an estimated sensitivity of 3.5 HIV RNA copies/ml.
Results
Four samples from subjects who did not sero-convert within the following six months were positive for HIV RNA. For one sample, human polymorphism DNA analysis indicated a sample mix up. Borderline HIV RNA detection signals were detected for the other three positive samples and further replicate TMA testing yielded no positive results. Nested PCR assays (n=254) for HIV proviral DNA on PBMC from these 3 subjects were negative.
Conclusions
Transient viremia was not reproducibly detected in highly HIV exposed seronegative men and women. If transient infections do occur, plasma HIV RNA levels may remain below the detection limits of the sensitive assay used here, be of very short duration, or viral replication may be restricted to mucosal surfaces or their draining lymphoid tissues.
doi:10.1097/QAD.0b013e3283440269
PMCID: PMC3458706  PMID: 21297421
4.  The Impact of the AIDS Drug Assistance Program (ADAP) on Use of Highly Active Antiretroviral and Antihypertensive Therapy among HIV-Infected Women 
Objectives
To evaluate the association between enrollment into an AIDS Drug Assistance Program (ADAP) and use of highly active antiretroviral therapy (HAART) and antihypertensive therapy.
Methods
Cross-sectional analyses of data were performed on HAART-eligible women enrolled in the California (n=439), Illinois (n=168), and New York (n=487) Women’s Interagency HIV Study (WIHS) sites. A subset of HIV-infected women with hypertension (n=395) was also analyzed. Unadjusted and adjusted backward stepwise elimination logistic regression measured the association between demographic, behavioral, and health service factors and non-use of HAART or antihypertensive medication.
Results
In adjusted analysis of HAART non-use, women without ADAP were significantly more likely not to use HAART (odds ratio [OR] = 2.4, 95% confidence interval [CI] = 1.5–3.7) than women with ADAP. In adjusted analysis of antihypertensive medication non-use, women without ADAP had an increased but not significant odds of antihypertensive medication non-use (OR = 2.4, 95% CI = 0.93–6.0) than women with ADAP.
Conclusions
Government-funded programs for prescription drug coverage, such as ADAP, may play an important role in how HIV-positive women to access and use essential medications for chronic diseases.
doi:10.1097/QAI.0b013e31820a9d04
PMCID: PMC3042745  PMID: 21239994
AIDS; antiretroviral therapy; hypertension; women; healthcare disparity; prescription insurance
5.  Glycated Hemoglobin in Diabetic Women with and Without HIV Infection: Data from the Women's Interagency HIV Study 
Antiviral therapy  2010;15(4):571-577.
Background
Limited data suggest that glycated hemoglobin (hemoglobin A1c; A1C) values may not reflect glycemic control accurately in HIV-infected individuals with diabetes.
Methods
We evaluated repeated measures of paired fasting glucose and A1C values in 315 HIV-infected and 109 HIV-uninfected diabetic participants in the Women's Interagency HIV Study. Generalized estimating equations used log A1C as the outcome variable, with adjustment for log fasting glucose concentration in all models.
Results
An HIV-infected woman on average had 0.9868 times as much A1C (that is, 1.32% lower; 95% confidence interval 0.9734-0.9904) as an HIV-uninfected woman with the same log fasting glucose concentration. In multivariate analysis, HIV serostatus was not associated, but white, other non-black race, and higher red blood cell mean corpuscular volume (MCV) were statistically associated with lower A1C values. Use of diabetic medication was associated with higher A1C values. In multivariate analysis restricted to HIV-infected women, white and other race, higher MCV, and HCV viremia were associated with lower A1C values whereas older age, use of diabetic medications and higher CD4 cell count were associated with higher A1C values. Use of combination antiretroviral therapy, protease inhibitors, zidovudine, stavudine, or abacavir was not associated with A1C values.
Conclusions
We conclude that A1C values were modestly lower in HIV-infected diabetic women relative to HIV-uninfected diabetic women after adjustment for fasting glucose concentration. The difference was abrogated by adjustment for MCV, race, and diabetic medication use. Our data suggest that in clinical practice A1C gives a reasonably accurate refection of glycemic control in HIV-infected diabetic women.
doi:10.3851/IMP1557
PMCID: PMC2943237  PMID: 20587850
6.  Antiretroviral Therapy Exposure and Insulin Resistance in the Women’s Interagency HIV Study 
Background
Evidence suggesting an increased risk of cardiovascular disease in HIV-infected individuals has heightened the need to understand the relation of HIV infection, antiretroviral therapy use, and non–HIV-related factors with insulin resistance (IR).
Methods
Prospective study of 1614 HIV-infected and 604 HIV-uninfected participants from the Women’s Interagency HIV Study between October 2000 and March 2007. Homeostasis model assessment (HOMA)–estimated IR at 11,019 semiannual visits.
Results
HIV-infected women reporting highly active antiretroviral therapy (HAART) had higher median HOMA than HIV-uninfected women {1.20 [95% confidence interval (CI): 1.11 to 1.30] times higher for those reporting protease inhibitor–containing HAART; 1.10 (95% CI: 1.01 to 1.20) times higher for those reporting non–protease inhibitor–containing HAART}. Among HIV-infected, cumulative exposure to nucleoside reverse transcriptase inhibitors (NRTIs) of >3 years was associated with HOMA 1.13 (95% CI: 1.02 to 1.25) times higher than the HOMA without any cumulative NRTI exposure. Cumulative exposure to the NRTI stavudine of >1 year was associated with HOMA 1.15 (95% CI: 1.05 to 1.27) times higher than the HOMA without any cumulative stavudine use. Family history of diabetes, hepatitis C virus seropositivity, higher body mass index, or reporting menopause was associated with higher HOMA.
Conclusions
Longer cumulative exposure to NRTI; in particular, stavudine is associated with greater IR in HIV-infected women.
PMCID: PMC2889144  PMID: 19186350
antiretroviral therapy; HIV; HOMA; insulin resistance; nucleoside reverse transcriptase inhibitor; protease inhibitor

Results 1-6 (6)