[Show abstract][Hide abstract] ABSTRACT: This communication describes the application of an existing intracellular methodology to the quantitation of tenofovir-diphosphate (TFV-DP) and emtricitabine-triphosphate (FTC-TP) from erythrocytes using dried blood spots (DBS). Concentrations were determined from a 3 mm DBS punch extracted into a 70:30 methanol:water solution (lysed cellular matrix). This extraction solution was then subjected to a previously validated analytical procedure for lysed cellular matrix. Experiments for DBS validation used replicate samples from study participants to demonstrate acceptable reproducibility with spot volumes ranging from 10 μL to 50 μL and punch location either from the edge or center of the spot. Analysis of paired DBS with purified red blood cells showed that a 3 mm DBS punch contained an average of 11.9 million cells for the observed hematocrit range of the participants (35% to 50%). Numerous stability tests were completed showing that whole blood in an EDTA vacutainer could sit for 24 hours at room temperature prior to spotting, and DBS could remain at room temperature for up to five days including shipment at ambient using 2-day delivery. DBS stability in storage was acceptable up to 18 months at –20 °C or –80 °C and DBS could undergo 4 Freeze/Thaw cycles. The described method was applied to HIV prophylaxis studies, demonstrating powerful associations with HIV acquisition through its ability to discriminate gradients of adherence.
Full-text · Article · Jan 2016 · Journal of pharmaceutical and biomedical analysis
[Show abstract][Hide abstract] ABSTRACT: Human and simian immunodeficiency viruses (HIV and SIV) exploit follicular lymphoid regions by establishing high levels of viral replication and dysregulating humoral immunity. Follicular regulatory T cells (TFR) are a recently characterized subset of lymphocytes that influence the germinal centre response through interactions with follicular helper T cells (TFH). Here, utilizing both human and rhesus macaque models, we show the impact of HIV and SIV infection on TFR number and function. We find that TFR proportionately and numerically expand during infection through mechanisms involving viral entry and replication, TGF-β signalling, low apoptosis rates and the presence of regulatory dendritic cells. Further, TFR exhibit elevated regulatory phenotypes and impair TFH functions during HIV infection. Thus, TFR contribute to inefficient germinal centre responses and inhibit HIV and SIV clearance.
Full-text · Article · Oct 2015 · Nature Communications
[Show abstract][Hide abstract] ABSTRACT: Determinants of HIV-infected women's genital tract mucosal immune health are not well understood. Because raltegravir (RAL) achieves relatively higher genital tract concentrations than ritonavir-boosted atazanavir (ATV), we examined whether a RAL-based regimen is associated with improved cervical immune reconstitution and less activation in HIV+ women compared to an ATV-based regimen.
Peripheral blood, cervical brushings, cervical-vaginal lavage (CVL), and cervical biopsies were collected from HIV+ women on TDF/FTC and either RAL (n=14) or ATV (n=19) with CD4+ T-cells >300 cells/mm3 and HIV RNA <48 copies/mL. HLA-DR+CD38+ T-cells were measured in blood and cervical cells using flow cytometry, CD4+ and CD8+ T-cells were quantified in cervical biopsies by immunofluorescent analysis, and HIV RNA (VL), ATV, and RAL concentrations were measured in CVL.
In a linear regression model of log(CVL concentration) versus both log(plasma concentration) and treatment group, RAL CVL level was 519% (95%CI: 133, 1525%) higher than for ATV (p<0.001). Genital tract VL was undetectable in 90% of subjects and did not differ by regimen. There were no significant differences between groups in terms of cervical %HLA-DR+CD38+CD4+ or CD8+ T-cells, CD4+ or CD8+ T-cells/mm2, or CD4:CD8 ratio. After adjusting for treatment time and group, CVL:plasma drug ratio was not associated with cervical CD4:CD8 ratio or immune activation (p>0.6).
Despite significantly higher genital tract penetration of RAL compared to ATV, there were no significant differences in cervical immune activation or reconstitution between women on these regimens, suggesting both drug regimens achieve adequate genital tract levels to suppress virus replication.
No preview · Article · Jun 2015 · AIDS research and human retroviruses
[Show abstract][Hide abstract] ABSTRACT: Elevated immune activation is associated with an increased risk of HIV acquisition. Tenofovir (TFV) has immunomodulatory properties in vitro, but how this extends in vivo remains unknown.
HIV-negative adults received daily coformulated TFV disoproxil fumarate 300 mg/emtricitabine (FTC) 200 mg for 30 days followed by a 30-day washout. Markers of T-cell activation, inflammation, and cytokines were measured before drug and on days 30 (on drug) and 60 (30-day washout). Data were analyzed using one-way analysis of variance/pairwise comparisons. Intracellular disposition of TFV-diphosphate and FTC-triphosphate in CD4 and CD8 T-cells and monocytes was characterized, and the relationship with immune activation was evaluated using Pearson's correlation coefficient.
T-cell activation was available in 19 participants. CD38/HLA-DR coexpression on CD8 T-cells decreased from baseline to day 30 (3.97% vs. 2.71%; P = 0.03) and day 60 (3.97% vs. 2.41%; P = 0.008). Soluble CD27 decreased from baseline to day 60 (184.1 vs. 168.4 pg/mL; P = 0.001). Cytokines and inflammation markers were not significantly different. TFV-diphosphate and FTC-triphosphate were approximately 4-fold higher in monocytes vs. CD4 and CD8 T-cells but neither correlated with activation markers.
TFV disoproxil fumarate/FTC therapy was associated with decreased T-cell activation in HIV-negative adults, which could contribute to the antiviral effect of pre-exposure prophylaxis (NCT01040091; www.clinicaltrials.gov).
No preview · Article · Apr 2015 · JAIDS Journal of Acquired Immune Deficiency Syndromes
[Show abstract][Hide abstract] ABSTRACT: Background. This study estimated the number of daily tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) doses required to achieve
and maintain (after discontinuation) intracellular drug concentrations that protect against human immunodeficiency virus (HIV)
infection for men who have sex with men (MSM).
Methods. Tenofovir diphosphate (TFV-DP) concentrations in peripheral blood mononuclear cells (PBMCs) and rectal mononuclear cells
from an intensive pharmacokinetic study (“Cell-PrEP” [preexposure prophylaxis]) of 30 days of daily TDF/FTC followed by 30
days off drug were evaluated. A regression formula for HIV risk reduction derived from PBMCs collected in the preexposure
prophylaxis initiative study was used to calculate inferred risk reduction. The time required to reach steady state for TFV-DP
in rectal mononuclear cells was also determined.
Results. Twenty-one HIV-uninfected adults participated in Cell-PrEP. The inferred HIV risk reduction, based on PBMC TFV-DP concentration,
reached 99% (95% confidence interval [CI], 69%–100%) after 5 daily doses, and remained >90% for 7 days after stopping drug
from steady-state conditions. The proportion of participants reaching the 90% effective concentration (EC90) was 77% after 5 doses and 89% after 7 doses. The percentage of steady state for natural log [TFV-DP] in rectal mononuclear
cells was 88% (95% CI, 66%–94%) after 5 doses and 94% (95% CI, 78%–98%) after 7 doses.
Conclusions. High PrEP activity for MSM was achieved by approximately 1 week of daily dosing. Although effective intracellular drug concentrations
persist for several days after stopping PrEP, a reasonable recommendation is to continue PrEP dosing for 4 weeks after the
last potential HIV exposure, similar to recommendations for postexposure prophylaxis.
Full-text · Article · Nov 2014 · Clinical Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: Simple and reproducible tools to assess antiretroviral adherence are needed. A level of tenofovir diphosphate (TFV-DP) in dried blood spots (DBS) <1250 fmol/punch is predicted to identify imperfect adherence. Herein we evaluated TFV-DP DBS as a measure of adherence among HIV-infected women. DBS and peripheral blood mononuclear cells (PBMCs) were collected twice (~1 week apart), in 35 well-controlled HIV-infected women (median age 42 years, 14 African American/Black [AA]) receiving daily co-formulated tenofovir/emtricitabine and either atazanavir/ritonavir (n=20) or raltegravir (n=16). TFV-DP in DBS and PBMCs was quantified by LC-MS/MS. Six-month adherence was measured as average days between monthly pharmacy refills. Data were loge transformed for analysis and presented as median (range); the correlation between continuous variables was analyzed using Pearson correlation coefficient. The average TFV-DP between the 2 visits (aTFV-DP) in DBS and PBMCs was 1874 (706-3776) fmol/punch and 125 (1-278) fmol/106cells, respectively. AA women had lower levels of aTFV-DP in DBS compared to whites (1660 vs. 1970 fmol/punch; P=0.04), with a viremic patient having the lowest drug level (706 fmol/punch). Days between pharmacy refills were 34 (30-54) vs. 30 (26-40) in women with TFV-DP in DBS <1250 vs. ≥1250 fmol/punch (P=0.006). TFV-DP in DBS was negatively correlated with increasing number of days between refills (r=-0.56, P=0.002). TFV-DP DBS was a reliable and objective measure of adherence in HIV-infected women based on a strong inverse relationship with pharmacy refill adherence.
Full-text · Article · Oct 2014 · AIDS Research and Human Retroviruses
[Show abstract][Hide abstract] ABSTRACT: Background:
Most HIV-1 replication occurs in secondary lymphoid tissues, and evaluating these tissues is crucial to investigations of pathogenesis. Inguinal lymph nodes (LN) are obtained frequently for these studies as they are readily detectable in most individuals and provide abundant numbers of cells. Knowledge of the outcomes of inguinal LN excision for research purposes is important to inform accurately study participants and researchers of the potential risks.
Data on surgical complications were collected in real time in HIV-1-infected subjects who underwent excisional inguinal LN biopsies for research purposes from February 1997 through June 2011. Data were analyzed retrospectively to determine the frequency of surgical complications using the Fisher exact test and non-parametric testing.
Eighty-seven research subjects underwent a total of 95 LN excisions. Thirty-six percent of subjects were female, 53% were white, 26% were black, 16% Hispanic, and 2% Native American. Median age was 36 y (22-52). The median CD4+ T cell count was 478 cell/mm(3) (range, 57-1117) and the median plasma HIV-1 RNA concentration was 4.1 log10copies/mL (range, 1.7-5.9). Minor complications including seroma, transient lymphedema, hematoma, and allergic reaction to surgical tape, occurred in 10% of procedures. Complications that required medical attention occurred in an additional 10% of procedures, and included cellulitis (5%), superficial incisional surgical site infection (3%), and seroma requiring aspiration (1%). Subjects with complications had a lower BMI (25; range, 16-38; n=12) than others (28; range, 19-57; n=40; p=0.05) and tended to have higher platelets, (median, 259×10(9)/L; range, 196-332; vs. 233×10(9)/L; range, 44-633; p=0.07). No other clinical or laboratory characteristics were associated with complications (p≥0.3).
Lymph node excision for research purposes is generally safe in a diverse group of chronically HIV-1-infected women and men, but can result in complications in a minority of subjects. No predictors of complications were identified.
No preview · Article · May 2014 · Surgical Infections
[Show abstract][Hide abstract] ABSTRACT: Tumor necrosis factor (TNF)-α, a pleiotropic pro-inflammatory cytokine involved in a variety of biological processes including oxidative stress, has been associated with vascular dysfunction in aged and ovariectomized animals. We determined whether acute inhibition of TNF-α improves vascular endothelial function and decreases arterial stiffness in estrogen-deficient postmenopausal women.
Arterial stiffness (carotid artery compliance) and endothelial function (brachial artery flow-mediated dilation [FMD]) were measured in postmenopausal women (n = 23; 57 ± 1 years, mean ± SE) before and following randomization to two days of either transdermal estradiol (0.05 mg/d, N = 12) or placebo (N = 11) alone and following a single subcutaneous injection of the TNF-α inhibitor, etanercept (25 mg), and in premenopausal (n = 9; 33 ± 2 years) before and following etanercept.
Baseline carotid artery compliance and brachial artery FMD were lower in postmenopausal than premenopausal women (P < 0.0001). In postmenopausal women, carotid artery compliance (n = 12; 0.59 ± 0.05-0.78 ± 0.06 mm(2)/mmHg × 10(-1), P < 0.001) and FMD (4.1 ± 0.6-6.0 ± 0.7%, P = 0.02) increased in response to estradiol but not placebo (n = 11). Carotid artery compliance (0.71 ± 0.06-0.81 ± 0.06 mm(2)/mmHg × 10(-1), P = 0.02) and FMD (5.2 ± 0.7-7.5 ± 0.9%, P = 0.003) increased with etanercept in the placebo group but had no effect in postmenopausal randomized to estradiol or premenopausal women. These results suggest that TNF-α contributes to impaired endothelial-dependent vasodilation and arterial stiffening in estrogen-deficient postmenopausal women.
[Show abstract][Hide abstract] ABSTRACT: A reversed-phase high performance liquid chromatographic (LC), tandem mass spectrometry (MS/MS) assay for the determination of tenofovir (TFV) and emtricitabine (FTC) in dried blood spots (DBS) from human whole blood was developed and validated. Whole blood samples were spotted, dried, and a 3mm punch was extracted with methanol for analysis by LC-MS/MS utilizing stable isotope labeled internal standards. The assay was validated over the range of 2.5-1000ng/mL for TFV and 2.5-5000ng/mL for FTC. The method was accurate (within ±15% of control) and precise (coefficient of variation ≤15%) for hematocrit concentrations ranging from 25% to 76%; using edge punches vs. center punches; and spot volumes of 10-50μL. Analytes were stable for five freeze/thaw cycles and up to 6 days at room temperature, whereas long-term storage required -20°C or -80°C. Comparison of TFV and FTC in DBS vs. plasma yielded r(2)≥0.96, indicating that DBS can be used as a plasma alternative for pharmacokinetic analyses in vivo.
Full-text · Article · Aug 2013 · Journal of pharmaceutical and biomedical analysis
[Show abstract][Hide abstract] ABSTRACT: The majority of HIV-infected individuals fail to produce protective antibodies and have diminished responses to new immunizations. We report here that even though there is an expansion of follicular helper T (TFH) cells in HIV-infected individuals, the cells are unable to provide adequate B cell help. We found a higher frequency of programmed cell death ligand 1 (PD-L1)+ germinal center B cells from lymph nodes of HIV-infected individuals suggesting a potential role for PD-1-PD-L1 interaction in regulating TFH cell function. In fact, we show that engagement of PD-1 on TFH cells leads to a reduction in cell proliferation, activation, inducible T-cell co-stimulator (ICOS) expression and interleukin-21 (IL-21) cytokine secretion. Blocking PD-1 signaling enhances HIV-specific immunoglobulin production in vitro. We further show that at least part of this defect involves IL-21, as addition of this cytokine rescues antibody responses and plasma cell generation in vitro. Our results suggest that deregulation of TFH cell-mediated B cell help diminishes B cell responses during HIV infection and may be related to PD-1 triggering on TFH cells. These results demonstrate a role for TFH cell impairment in HIV pathogenesis and suggest that enhancing their function could have a major impact on the outcome and control of HIV infection, preventing future infections and improving immune responses to vaccinations.
[Show abstract][Hide abstract] ABSTRACT: Context:The stages of the menopause transition are characterized by changes in ovarian hormones and increased cardiovascular disease (CVD) risk factors and vasomotor symptoms that may adversely affect vascular health.Objective:We tested the hypothesis that endothelial function, a predictor of CVD, would be reduced across the stages of the menopause transition, independent of CVD risk factors and vasomotor symptoms.Design, Setting, and Participants:This was a cross-sectional study of 132 healthy women from the general community aged 22-70 yr, categorized as premenopausal (n = 33, 32 ± 6 yr; mean ± sd), early perimenopausal (n = 20, 49 ± 3 yr) or late perimenopausal (n = 22, 50 ± 4 yr), or early (n = 30, 55 ± 3 yr) or late postmenopausal (n = 27, 61 ± 4 yr).Main Outcome:Endothelial-dependent vasodilation was measured by brachial artery flow-mediated dilation (FMD) using ultrasound.Results:Brachial artery FMD was significantly different among the groups (P < 0.001). It was highest in premenopausal women (9.9 ± 2.1%) with progressive decrements in perimenopausal (early: 8.2 ± 2.5%; late: 6.5 ± 1.9%) and postmenopausal women (early: 5.5 ± 1.9%; late: 4.7 ± 1.7%). Adjustment for risk factors, vasomotor symptoms, and sex hormones did not alter the association (P < 0.001). In subgroup analyses of women aged 50-59 yr, brachial artery FMD was lower in late peri- and early and late postmenopausal compared with early perimenopausal women (P < 0.001) but was not different between late perimenopausal and either early or late postmenopausal women.Conclusions:Our findings suggest that a decline in endothelial function begins during the early stages of menopause (perimenopause) and worsens with the loss of ovarian function and prolonged estrogen deficiency. These data add to the accumulating evidence that the perimenopausal window is a critical time period for adverse changes in CVD risk.
No preview · Article · Sep 2012 · The Journal of Clinical Endocrinology and Metabolism
[Show abstract][Hide abstract] ABSTRACT: Abstract Tenofovir (TFV) disoproxil fumarate (TDF)±emtricitabine (FTC) are widely used for HIV treatment and chemoprophylaxis, but variable adherence may lead to suboptimal responses. Methods that quantify adherence would allow for interventions to improve treatment and prevention outcomes. Our objective was to characterize the pharmacokinetics of TFV-diphosphate (TFV-DP) and FTC-triphosphate (FTC-TP) in red blood cells (RBCs) and peripheral blood mononuclear cells (PBMCs); to extend the RBC analysis to dried blood spots (DBSs); and to model how RBC/DBS monitoring could inform recent and cumulative drug exposure/adherence. Blood samples were collected from 17 HIV-negative adults at 5 visits over a 30-day pharmacokinetics study of daily oral TDF/FTC. Dosing was discontinued on day 30 and blood was collected on days 35, 45, and 60 during the washout period. Plasma/RBCs/PBMCs/DBSs were all quantified by liquid chromatography/tandem mass spectrometry. DBSs were paired with RBCs and plasma for comparisons. The median (interquartile range) RBC TFV-DP half-life was 17.1 (15.7-20.2) versus 4.2 (3.7-5.2) days in PBMCs. At steady state, TFV-DP was 130 fmol/10(6) RBCs versus 98 fmol/10(6) PBMCs. FTC-TP was not quantifiable in most RBC samples. TFV-DP in RBCs versus DBSs yielded an r(2)=0.83. TFV-DP in DBSs was stable at -20°C. Simulations of TFV-DP in RBCs/DBSs, when dosed from one to seven times per week, demonstrated that each dose per week resulted in an average change of approximately 19 fmol/10(6) RBCs and 230 fmol/punch. TFV and FTC in plasma versus DBSs was defined by y=1.4x; r(2)=0.96 and y=0.8x; r(2)=0.99, respectively. We conclude that DBSs offer a convenient measure of recent (TFV/FTC) and cumulative (TFV-DP in RBCs) drug exposure with potential application to adherence monitoring.
No preview · Article · Aug 2012 · AIDS research and human retroviruses
[Show abstract][Hide abstract] ABSTRACT: The cellular pharmacology of zidovudine (ZDV) and lamivudine (3TC) in vivo is not completely understood. This prospective longitudinal study investigated the relationship between HIV-1 serostatus,
sex, race, and time on therapy with intracellular and plasma ZDV and 3TC concentrations. Of 20 HIV-seronegative and 23 HIV-seropositive
volunteers enrolled, 16 (8 women) and 21 (5 women) completed all 12 study days, respectively. Volunteers began ZDV-3TC therapy
(plus a third active drug in HIV-seropositive volunteers), and steady-state concentrations (Css) were determined after days 1, 3, 7, and 12. A repeated-measures mixed model was utilized. HIV-seronegative status was associated
with 22% (95% confidence interval [CI], 0%, 50%) and 37% (15%, 67%) higher Css estimates compared to those of HIV-seropositive individuals for intracellular ZDV-TP and 3TC-TP levels, respectively. African-Americans
had 36% (8%, 72%) higher ZDV-TP estimates than non-African-Americans. Sex was not associated with ZDV-TP or 3TC-TP (P > 0.19). Women had 36% (4%, 78%) higher plasma ZDV, but the effect was lessened when normalized by lean body weight (5% [−19%,
38%]; P = 0.68). Plasma 3TC was 19% (0%, 41%) higher in HIV-seropositive volunteers and 22% (0%, 48%) higher in African American
volunteers, but these effects were not significant when corrected for creatinine clearance (7% [−9%, 20%] and −5% [−26%, 12%]
for HIV serostatus and race, respectively; P > 0.35). These results suggest that HIV-seropositive status decreases and African American race elevates the cellular triphosphates
of ZDV and 3TC. This information extends knowledge of ZDV and 3TC cellular pharmacology in vivo and provides new leads for future cellular pharmacology studies aimed at optimizing HIV prevention/treatment with these agents.
Full-text · Article · Mar 2012 · Antimicrobial Agents and Chemotherapy
[Show abstract][Hide abstract] ABSTRACT: The mechanisms mediating arterial stiffening with aging and menopause are not completely understood. We determined whether administration of tetrahydrobiopterin (BH(4)), a critical cofactor for endothelial nitric oxide synthase to produce nitric oxide, would increase vascular endothelial-dependent vasodilatory tone and decrease arterial stiffness in estrogen-deficient postmenopausal women. Additionally, we examined whether the beneficial effects of estrogen on vascular function were possibly related to BH(4). Arterial stiffness (carotid artery compliance) and endothelial-dependent vasodilation [brachial artery flow-mediated dilation (FMD)] were measured in postmenopausal (n = 24; 57 ± 1 yr, mean ± SE) and eumenorrheic premenopausal (n = 9; 33 ± 2 yr) women before and 3 h after the oral administration of BH(4). Subsequently, in postmenopausal women, vascular testing (before and after BH(4)) was repeated following randomization to either 2 days of transdermal estradiol or placebo. Baseline carotid artery compliance and brachial artery FMD were lower in postmenopausal than in premenopausal women (P < 0.0001). BH(4) administration increased carotid artery compliance (0.61 ± 0.05 to 0.73 ± 0.04 mm(2)·mmHg(-1)·10(-1) vs. baseline, P < 0.0001) and brachial artery FMD (P < 0.001) in postmenopausal women but had no effect in premenopausal women (P = 0.62). Carotid artery compliance (0.59 ± 0.05 to 0.78 ± 0.06 mm(2)·mmHg(-1)·10(-1), P < 0.001) and FMD increased in postmenopausal women in response to estradiol (P = 0.02) but were not further improved with the coadministration of BH(4), possibly because estrogen increased BH(4) bioavailability. Carotid artery compliance and FMD increased with BH(4) in the placebo group (P = 0.02). Although speculative, these results suggest that reduced vascular BH(4) may be an important contributor to arterial stiffening in estrogen-deficient postmenopausal women, related in part to reduced endothelial-dependent vasodilatory tone.
Preview · Article · Mar 2012 · AJP Heart and Circulatory Physiology
[Show abstract][Hide abstract] ABSTRACT: New HIV-1 infections are increasing in older American women largely through heterosexual transmission. Activated CD4+ T cells and CCR5 expression are linked to HIV-1 susceptibility, but whether these parameters are altered in the cervix of older women is unknown.
Whole blood and in some instances endocervical brush samples were collected from healthy premenopausal (n = 22) and postmenopausal women (n = 24). Percentages of HLA-DR(DR)+CD38(38)+CD4+ T cells and HIV-1 chemokine coreceptor expression were determined by flow cytometry.
Percentages of DR+38+CD4+ T cells were 6 times greater in cervix (median: 6.4%) than blood (median: 1.1%; P < 0.001) but did not differ within each compartment between premenopausal and postmenopausal women (P = 0.2). Postmenopausal women had greater percentages of CCR5+CD4+ and CCR5+DR+38+CD4+ T cells compared with premenopausal women in cervix (median: 70% vs. 42%, P = 0.005; and 80% vs. 57%; P = 0.05, respectively) and blood (medians: 22% vs. 13%, and 76% vs. 62%, respectively; P < 0.001). Postmenopausal women had more CCR5 molecules on cervical DR+38+CD4+ T cells (median: 3176) than premenopausal women (median: 1776; P = 0.02). Age and percent CCR5+CD4+ and CCR5+DR+38+CD4+ cells were linearly related in cervix (r(2) = 0.47, P < 0.001 and r(2) = 0.25, P = 0.01, respectively) and blood (r(2) = 0.20, P = 0.001 and r(2) = 0.31, P < 0.001; respectively), but confounding of age with menopause could not be excluded. Cervical CXCR4 expression did not differ substantially between premenopausal and postmenopausal women.
Elevated cervical CCR5 expression in postmenopausal women may increase their risk for HIV-1 acquisition. Studies are needed to confirm whether elevated CCR5 expression confers increased HIV-1 susceptibility in postmenopausal women, and if it is related to hormonal or nonhormonal effects of aging.
Full-text · Article · Nov 2011 · JAIDS Journal of Acquired Immune Deficiency Syndromes
[Show abstract][Hide abstract] ABSTRACT: Abstract Raltegravir, an inhibitor of the human immunodeficiency virus-1 (HIV-1) integrase enzyme, is a preferred component of antiretroviral regimens for both treatment-naïve and -experienced patients. Compared with other antiretroviral agents, raltegravir has less toxicity and fewer drug interactions since it is not a substrate, inhibitor, or inducer of cytochrome P450 enzymes. However, raltegravir is not devoid of drug interactions. We describe a 39-year-old, HIV-1-infected man who experienced virologic failure while receiving a raltegravir-containing antiretroviral regimen with concomitant calcium administration. The patient was prescribed protease inhibitor-based combination antiretroviral therapy, and within 2 months, he achieved undetectable plasma HIV-1 RNA levels. Seven months after starting therapy, he developed a focal cerebral vasculitis of unknown etiology, which was treated with prednisone, aspirin, and acyclovir. Due to the potential for drug interactions between prednisone and protease inhibitors, the patient was switched to an antiretroviral regimen containing raltegravir. In addition, calcium carbonate 1 g-vitamin D3 400 IU 3 times/day was started for prevention of osteoporosis associated with long-term glucocorticoid use. After 10 months of an undetectable plasma HIV-1 RNA level and clinical evidence of a high level of adherence, he subsequently developed detectable HIV-1 RNA levels with documented resistance to raltegravir. His antiretroviral therapy was changed back to a protease inhibitor-based regimen, and his HIV-1 RNA level rapidly resuppressed. Calcium binding to the divalent metal ion-chelating motif of raltegravir may have led to subtherapeutic raltegravir levels in this patient. It is important for clinicians to be aware of the potential interaction between polyvalent cation-containing agents, such as calcium, and raltegravir.
[Show abstract][Hide abstract] ABSTRACT: Percentages of activated T cells correlate with HIV-1 disease progression, but the underlying mechanisms are not fully understood.
We hypothesized that HLA-DR+ CD38+ (DR+ 38+) CD4+ T cells produce the majority of HIV-1 due to elevated expression of CCR5 and CXCR4. In phytohemagglutinin (PHA)-stimulated
CD8-depleted peripheral blood mononuclear cells (PBMC) infected with HIV-1 green fluorescent protein (GFP) reporter viruses,
DR− 38+ T cells constituted the majority of CCR5 (R5)-tropic (median, 62%) and CXCR4 (X4)-tropic HIV-1-producing cells (median, 61%),
although cell surface CCR5 and CXCR4 were not elevated in this subset of cells. In lymph nodes from untreated individuals
infected with R5-tropic HIV-1, percentages of CCR5+ cells were elevated in DR+ 38+ CD4+ T cells (median, 36.4%) compared to other CD4+ T-cell subsets (median values of 5.7% for DR− 38− cells, 19.4% for DR+ 38− cells, and 7.6% for DR− 38+ cells; n = 18; P < 0.001). In sorted CD8− lymph node T cells, median HIV-1 RNA copies/105 cells was higher for DR+ 38+ cells (1.8 × 106) than for DR− 38− (0.007 × 106), DR− 38+ (0.064 × 106), and DR+ 38− (0.18 × 106) subsets (n = 8; P < 0.001 for all). After adjusting for percentages of subsets, a median of 87% of viral RNA was harbored by DR+ 38+ cells. Percentages of CCR5+ CD4+ T cells and concentrations of CCR5 molecules among subsets predicted HIV-1 RNA levels among CD8− DR/38 subsets (P < 0.001 for both). Median HIV-1 DNA copies/105 cells was higher in DR+ 38+ cells (5,360) than in the DR− 38− (906), DR− 38+ (814), and DR+ 38− (1,984) subsets (n = 7; P ≤ 0.031). Thus, DR+ 38+ CD4+ T cells in lymph nodes have elevated CCR5 expression, are highly susceptible to infection with R5-tropic virus, and produce
the majority of R5-tropic HIV-1. PBMC assays failed to recapitulate in vivo findings, suggesting limited utility. Strategies to reduce numbers of DR+ 38+ CD4+ T cells may substantially inhibit HIV-1 replication.
Full-text · Article · Aug 2011 · Journal of Virology
[Show abstract][Hide abstract] ABSTRACT: It is unknown whether sex and race influence clinical outcomes following primary human immunodeficiency virus type 1 (HIV-1) infection.
Data were evaluated from an observational, multicenter, primarily North American cohort of HIV-1 seroconverters.
Of 2277 seroconverters, 5.4% were women. At enrollment, women averaged .40 log₁₀ fewer copies/mL of HIV-1 RNA (P < .001) and 66 more CD4(+) T cells/μL (P = .006) than men, controlling for age and race. Antiretroviral therapy (ART) was less likely to be initiated at any time point by nonwhite women and men compared to white men (P < .005), and by individuals from the southern United States compared to others (P = .047). Sex and race did not affect responses to ART after 6 months (P > .73). Women were 2.17-fold more likely than men to experience >1 HIV/AIDS-related event (P < .001). Nonwhite women were most likely to experience an HIV/AIDS-related event compared to all others (P = .035), after adjusting for intravenous drug use and ART. Eight years after diagnosis, >1 HIV/AIDS-related event had occurred in 78% of nonwhites and 37% of whites from the southern United States, and 24% of whites and 17% of nonwhites from other regions (P < .001).
Despite more favorable clinical parameters initially, female HIV-1-seroconverters had worse outcomes than did male seroconverters. Elevated morbidity was associated with being nonwhite and residing in the southern United States.
Full-text · Article · Feb 2011 · The Journal of Infectious Diseases
[Show abstract][Hide abstract] ABSTRACT: The use of antiretroviral medications in HIV-negative individuals as pre-exposure prophylaxis (PrEP) is a promising approach to prevent HIV infection. Tenofovir disoproxil fumarate (TDF) and emtricitabine exhibit desirable properties for PrEP including: favourable pharmacokinetics that support infrequent dosing; few major drug-drug or drug-food interactions; an excellent clinical safety record; and pre-clinical evidence for efficacy. Several large, randomized, controlled clinical trials are evaluating the safety and efficacy of TDF and emtricitabine for this new indication. A thorough understanding of variability in drug response will help determine future investigations in the field and/or implementation into clinical care. Because tenofovir and emtricitabine are nucleos(t)ide analogues, the HIV prevention and toxicity effects depend on the triphosphate analogue formed intracellularly. This review identifies important cellular pharmacology considerations for tenofovir and emtricitabine, which include drug penetration into relevant tissues and cell types, race/ethnicity/pharmacogenetics, gender, cellular activation state and appropriate episodic or alternative dosing strategies based on pharmacokinetic principles. The current state of knowledge in these areas is summarized and the future utility of intracellular pharmacokinetics/pharmacodynamics for the PrEP field is discussed.
Preview · Article · Nov 2010 · Journal of Antimicrobial Chemotherapy