Immunologic, virologic, and pharmacologic characterization of the female upper genital tract in HIV-infected women

A post-mortem analysis of tenofovir, lamivudine, efavirenz and fluconazole penetration in female genital tissues

BACKGROUND

Optimal penetration of anti-infectives in the female genital tract (FGT) is paramount in the treatment and prevention of infectious diseases. While exposure of anti-infectives in lower FGT tissues (e.g. cervix, vagina) has been described, little data exist on upper genital tissues (e.g. ovary, uterus).

METHODS

Autopsies were performed and post-mortem tissues were collected within 24 h of death for female participants with advanced HIV in Uganda (n = 27). Tenofovir, lamivudine, efavirenz and fluconazole concentrations were measured using LC-MS/MS in plasma, ovarian, uterine, cervical and vaginal tissues. Tissue penetration was calculated as tissue-to-plasma concentration ratios (TPRs).

RESULTS

TPRs of tenofovir, lamivudine and fluconazole were highest in vaginal tissue (medians 1.86, 1.83 and 0.94, respectively), while the TPR of efavirenz was highest in ovarian tissue (median 0.65). With cervix as a reference compartment, vaginal TPRs were significantly higher than cervical for all four drugs; TPRs of efavirenz in uterine and ovarian compartments were also significantly higher than cervical. Most of the post-mortem FGT samples had a TPR of greater than 1 for tenofovir and lamivudine, while less than 50% had a TPR of greater than 1 for both efavirenz and fluconazole.

CONCLUSIONS

Penetration of anti-infectives was not homogeneous among the FGT compartments. Approximately 70% of FGT tissues had a TPR of greater than 1 for tenofovir and lamivudine, favouring the prevention of local HIV replication and transmission in the FGT.

Intracellular Tenofovir and Emtricitabine Concentrations in Younger and Older Women with HIV Receiving Tenofovir Disoproxil Fumarate/Emtricitabine

The altered immune states of aging and HIV infection may affect intracellular metabolism of tenofovir disoproxil fumarate (TDF) and emtricitabine (FTC); increased cellular senescence decreases FTC-triphosphate (FTCtp) concentrations. The effects of age and inflammation on the ratio of intracellular metabolites (IMs; tenofovir diphosphate [TFVdp] and FTCtp) to their endogenous nucleotides (ENs; dATP and dCTP), a potential treatment efficacy marker, were assessed among participants of the Women's Interagency HIV Study (WIHS), who ranged from 25 to 75 years. Samples from women receiving TDF-FTC with viral loads of <200 copies/ml were dichotomized by age at collection into two groups (≤45 years and ≥60 years). IM/EN concentrations were measured in peripheral blood mononuclear cell (PBMC) pellets; interleukin-6 (IL-6) and sCD163 were measured in plasma; senescent CD8⁺ T cells were measured in viable PBMCs. The TFVdp:dATP and FTCtp:dCTP ratios had statistically significantly different distributions in older and younger women (log-rank test, P = 0.0023 and P = 0.032, respectively); in general, IM and EN concentrations were higher in the older women. After adjusting for potential confounders, these findings were not significant. In women aged ≤45 years, TFVdp was negatively associated with IL-6 and sCD163, while FTCtp was positively associated with sCD163 and IL-6 in women aged ≥60 years. Body mass index (BMI) was positively associated with IL-6 in both age groups and negatively associated with TFVdp in women aged ≤45 years. After adjustment, age remained significant for sCD163, while black race, BMI, and renal function remained significant for several IMs and ENs, suggesting that factors associated with aging, but not age itself, govern intracellular TDF-FTC pharmacology.

Female genital tract shedding of HIV-1 is rare in women with suppressed HIV-1 in plasma

OBJECTIVE

Determine the frequency of genital HIV-1 shedding in a large cohort of women on long-term suppressive antiretroviral therapy (ART) and its association with mucosal inflammation.

DESIGN

We measured levels of HIV-1 RNA and inflammation biomarkers in cervicovaginal lavage (CVL) from HIV-seropositive women enrolled in the Women's Interagency HIV Study (WIHS).

METHODS

HIV-1 was quantified (Abbott RealTime HIV-1 assay) from CVL samples of 332 WIHS participants with and without clinical evidence of genital inflammation at the time of CVL collection; participants had suppressed plasma viral load (PVL; limit of quantitation less than 20-4000 copies/ml depending on year of collection) for a median of 7.1 years [interquartile range (IQR) 3.4-9.8, Group 1] or for a median of 1.0 years (IQR = 0.5-1.0, Group 2). Twenty-two biomarkers of inflammation were measured in CVL to compare with clinical markers.

RESULTS

HIV-1 was detected in 47% of 38 pre-ART CVL samples (median 668 copies/ml) and detection in CVL was associated with higher pre-ART PVL. HIV-1 was detected in only 1 of 38 CVL samples from these women on suppressive antiretroviral therapy for 1 year. No HIV-1 RNA was detected in 294 CVL samples from a cross-sectional set of women with suppressed PVL for a median of 7 years. Clinical inflammation markers were correlated with inflammatory biomarkers in CVL specimens, although genital inflammation was not associated with measurable genital HIV-1 shedding in these WIHS participants on ART.

CONCLUSION

ART that suppresses HIV-1 in the plasma of women also prevents genital tract HIV-1 shedding, even in the presence of genital tract inflammation.

Mucosal Immunity in HIV/SIV Infection: T Cells, B Cells and Beyond

As our understanding of mucosal immunity increases, it is becoming clear that the host response to HIV-1 is more complex and nuanced than originally believed. The mucosal landscape is populated with a variety of specialized cell types whose functions include combating infectious agents while preserving commensal microbiota, maintaining barrier integrity, and ensuring immune homeostasis. Advances in multiparameter flow cytometry, gene expression analysis and bioinformatics have allowed more detailed characterization of these cell types and their roles in host defense than was previously possible. This review provides an overview of existing literature on immunity to HIV-1 and SIVmac in mucosal tissues of the female reproductive tract and the gastrointestinal tract, focusing on major effector cell populations and briefly summarizing new information on tissue resident memory T cells, T_reg, Th17, Th22 and innate lymphocytes (ILC), subsets that have been studied primarily in the gastrointestinal mucosa.

Pharmacology of Antiretrovirals in the Female Genital Tract for HIV Prevention

Preexposure prophylaxis (PrEP) is a powerful tool that, as part of a comprehensive prevention package, has potential to significantly impact the HIV epidemic. PrEP effectiveness is believed to be dependent on the exposure and efficacy of antiretrovirals at the site of HIV transmission. Clinical trial results as well as modeling and simulation indicate the threshold of adherence required for PrEP efficacy of emtricitabine/tenofovir disoproxil fumarate may differ between sites of HIV transmission with less forgiveness for missed doses in women exposed through genital tissue compared to people exposed through colorectal tissue. This suggests a role for local and host factors to influence mucosal pharmacology. Here we review the mucosal pharmacology of antiretrovirals in the female genital tract and explore potential determinants of PrEP efficacy. Host factors such as inflammation, coinfections, hormonal status, and the vaginal microbiome will be explored as well as the role of drug-metabolizing enzymes and transporters in regulating local drug exposure. The use of preclinical and early clinical models to predict clinical effectiveness is also discussed.

Virological and immunological responses to raltegravir and dolutegravir in the gut-associated lymphoid tissue of HIV-infected men and women

BACKGROUND

Raltegravir (RTG) and dolutegravir (DTG) have different pharmacokinetic patterns in the gastrointestinal tract. To determine if this results in pharmacodynamic differences, we compared HIV RNA, HIV DNA and immunological markers in gut-associated lymphoid tissue (GALT) of HIV-infected participants receiving RTG or DTG with tenofovir+emtricitabine (TDF/FTC).

METHODS

GALT specimens from the terminal ileum, splenic flexure and rectum were obtained by colonoscopy at a single time point in 20 adults treated with RTG (n=10) or DTG (n=10) with HIV RNA <50 copies/ml. Flow cytometry, drug concentrations, and HIV RNA and DNA were analysed in tissue. CD4/8+ T-cells were tested for γδ TCR, and markers of T-cell activation and exhaustion. Data are reported as median (Q1-Q3).

RESULTS

A total of 15 men and 5 women were enrolled. There was no difference in time since HIV diagnosis for those on RTG (9.5 [4-22] years) and DTG (17 [1-24] years; P=0.6), although time on RTG (5.4 [2.3-6.7] years) was greater than DTG (1.0 [0.1-1.5] years; P<0.001). Concentrations of RTG and DTG in rectal tissue were similar to previous reports: median tissue:plasma ratio was 11.25 for RTG and 0.44 for DTG. RNA:DNA ratios were 1.14 (0.18-5.10) for the RTG group and 0.90 (0.30-18.87) for the DTG group (P=0.95). No differences (P≥0.1) between CD4+ and CD8+ T-cell markers were found.

CONCLUSIONS

RTG produced higher tissue exposures than DTG, but no significant differences in GALT HIV RNA, DNA or most immunological markers were observed. ClinicalTrials.gov NCT02218320.

Hormonal Contraceptives Differentially Suppress TFV and TAF Inhibition of HIV Infection and TFV-DP in Blood and Genital Tract CD4+ T cells

HIV prevention research is focused on combining antiretrovirals (ARV) and progestin contraceptives to prevent HIV infection and pregnancy. The possibility that progestins compromise ARV anti-HIV activity prompted us to evaluate the effects of progestins on tenofovir (TFV) and TFV-alafenamide (TAF) on HIV infection and intracellular TFV-diphosphate (TFV-DP) concentrations in blood and genital CD4+ T cells. Following incubation of blood CD4+ T cells with TFV or TAF, Medroxyprogesterone acetate (MPA), but not Levonorgestrel, Norethisterone or progesterone, suppressed the anti-HIV effect of TFV by reducing intracellular TFV-DP, but had no effect on TAF inhibition of infection or TFV-DP. In contrast, with genital CD4+ T cells, MPA suppressed TAF inhibition of HIV infection and lowered of TFV-DP concentrations without affecting TFV protection. These findings demonstrate that MPA selectively compromises TFV and TAF protection in blood and genital CD4+ T cells and suggests that MPA may decrease ARV protection in individuals who use ARV intermittently for prevention.