A dual chamber model of female cervical mucosa for the study of HIV transmission and for the evaluation of candidate HIV microbicides

The use of microbicides is a promising approach for the prevention of HIV-1 transmission. Unfortunately, various candidates failed in clinical trials. In some cases, the candidate microbicide even resulted in enhanced virus transmission. Therefore, there is an urgent need to develop more predictive preclinical strategies to anticipate the in vivo efficiency/toxicity rate, including in vitro assays that evaluate effects on epithelial integrity and inflammation. The present study aims to identify potential safety issues concerning the use of microbicides and excipients commonly used in vaginal microbicide preparations. The toxicities of various active pharmaceutical ingredients (APIs; TMC-120, UC-781, tenofovir [PMPA], PRO-2000, and glycerol monolaurate [GML]) and excipients (preservatives, cosolvents, surfactants, and cyclodextrins) were evaluated using an in vitro dual-chamber model and uterine cervical explants. Epithelial viability and permeation of fluorescent virus-sized beads, as well as induction of interleukin-8 (IL-8; as a sensitive marker of an inflammatory response), were assessed. Surprisingly, cell viability and epithelial layer integrity were compromised by most excipients at concentrations near the typical concentration used in vaginal gels, and a significant increase in the production of IL-8 was observed at subtoxic concentrations. Within the APIs, TMC-120, UC-781, and PMPA showed higher selectivity indices than PRO-2000 and GML. In conclusion, identification of safety issues concerning the use of pharmaceutical excipients could help to formulate less toxic vaginal microbicide preparations.

Section: Discussionsupporting

confidence: 81%

Section: Discussionmentioning

confidence: 63%

In Vitro Evaluation of Viability, Integrity, and Inflammation in Genital Epithelia upon Exposure to Pharmaceutical Excipients and Candidate Microbicides

Gali

Delézay

Brouwers

et al. 2010

“…Cell-associated HIV was shown to pass the epithelial monolayer and infect the underlying target cells in vitro (10,11). In agreement with this information, seminal cells (12) and macrophages (13) were shown to penetrate the epithelium in cervical explant tissues and thus could potentially deliver HIV to target cells.…”

supporting

confidence: 64%

MIV-150/Zinc Acetate Gel Inhibits Cell-Associated Simian-Human Immunodeficiency Virus Reverse Transcriptase Infection in a Macaque Vaginal Explant Model

Barnable

Calenda

Bonnaire

et al. 2015

The transmission of both cell-free and cell-associated immunodeficiency viruses has been demonstrated directly in multiple animal species and possibly occurs in humans, as suggested by genotyping of the infecting human immunodeficiency virus (HIV) in acutely infected women and in semen from their partners. Therefore, a microbicide may need to block both mechanisms of HIV transmission to achieve maximum efficacy. To date, most of the preclinical evaluation of candidate microbicides has been performed using cell-free HIV. New models of mucosal transmission of cell-associated HIV are needed to evaluate candidate microbicide performance. The MIV-150/zinc acetate/carrageenan (MZC) gel protects Depo-Provera-treated macaques against cell-free simian-human immunodeficiency virus reverse transcriptase (SHIV-RT) infection when applied vaginally up to 8 h before challenge. We recently demonstrated the potent activity of MZC gel against cell-free SHIV-RT in macaque vaginal explants. In the current study, we established a cell-associated SHIV-RT infection model of macaque vaginal tissues and tested the activity of MZC gel in this model. MZC gel protected tissues against cell-associated SHIV-RT infection when present at the time of viral exposure or when applied up to 4 days prior to viral challenge. These data support clinical testing of the MZC gel. Overall, our ex vivo model of cell-associated SHIV-RT infection in macaque vaginal mucosa complements the cell-free infection models, providing tools for prioritization of products that block both modes of HIV transmission. Women account for about half of human immunodeficiency virus type 1 (HIV-1) infections, with the majority of infections transmitted via sexual intercourse (1). A longitudinal study reported that the genotype of the infecting HIV-1 in acutely infected women closely matches the virus in the seminal plasma and seminal cells from their chronically infected sexual partners (2), suggesting that transmission of both cell-free and cell-associated HIV-1 occurs in vivo. Furthermore, transmitter/founder donor variants were identified in peripheral blood mononuclear cells (PBMCs) and blood plasma, also suggesting that both cell-free transmission and cell-associated HIV transmission occur in vivo (3, 4). Which mode of transmission has a primary role in the establishment of mucosal infection is yet to be determined (5).Cell-to-cell HIV transmission is associated with efficient in vitro viral transfer through virological synapses (6-9). Cell-associated HIV was shown to pass the epithelial monolayer and infect the underlying target cells in vitro (10, 11). In agreement with this information, seminal cells (12) and macrophages (13) were shown to penetrate the epithelium in cervical explant tissues and thus could potentially deliver HIV to target cells. Recent studies mimicking HIV transmission in the intestinal tract in a rectal explant model revealed that ex vivo transmission of cell-associated simian immunodeficiency virus (SIV mac251 ) is more efficient than transmission o...

“…Furthermore, dapivirine demonstrates at least 10-fold greater activity than the structurally different NNRTI UC781 (10,48,54). Importantly, dapivirine activity was retained in the presence of biological fluids (CM and WS) ( Table 2).…”

Section: Discussionmentioning

confidence: 93%

“…Interestingly, dapivirine (225 and 22.5 M) demonstrated protection (85.7 and 78.6%, respectively) against a cellassociated HIV SF162 challenge 20 min following vaginal application in the hu-SCID mouse model (8), suggesting that dapivirine has the potential to block infection following topical application. While it is not yet known how much vaginally delivered drug would be absorbed across the mucosa to reach target cells, it has been shown in vitro that significant amounts of dapivirine are able to diffuse through a confluent epithelial layer (54). Clinical trials are currently evaluating the safety of a 0.05% gel, equivalent to 1.5 mM dapivirine.…”

Section: Discussionmentioning

confidence: 99%

Inhibition of Human Immunodeficiency Virus Type 1 Infection by the Candidate Microbicide Dapivirine, a Nonnucleoside Reverse Transcriptase Inhibitor

Fletcher

Harman

Azijn³

et al. 2009

Heterosexual transmission of human immunodeficiency virus (HIV) remains the major route of infection worldwide; thus, there is an urgent need for additional prevention strategies, particularly strategies that could be controlled by women, such as topical microbicides. Potential microbicide candidates must be both safe and effective. Using cellular and tissue explant models, we have evaluated the activity of the nonnucleoside reverse transcriptase inhibitor (NNRTI) dapivirine as a vaginal microbicide. In tissue compatibility studies, dapivirine was well tolerated by epithelial cells, T cells, macrophages, and cervical tissue explants. Dapivirine demonstrated potent dose-dependent inhibitory effects against a broad panel of HIV type 1 isolates from different clades. Furthermore, dapivirine demonstrated potent activity against a wide range of NNRTI-resistant isolates. In human cervical explant cultures, dapivirine was able not only to inhibit direct infection of mucosal tissue but also to prevent the dissemination of the virus by migratory cells. Activity was retained in the presence of semen or a cervical mucus simulant. Furthermore, dapivirine demonstrated prolonged inhibitory effects: it was able to prevent both localized and disseminated infection for as long as 6 days posttreatment. The prolonged protection observed following pretreatment of genital tissue and the lack of observable toxicity suggest that dapivirine has considerable promise as a potential microbicide candidate.