Original research articleDisruption of the upper female reproductive tract epithelium by nonoxynol-9☆
Introduction
Nearly 50 million individuals have been infected with human immunodeficiency virus (HIV) since the epidemic began more than two decades ago. Of the nearly 14,000 new cases of HIV infection occurring in the world each day, almost 90% are due to heterosexual transmission [1], [2]. A rapidly growing proportion of these new cases involves women [3], [4]. Contraceptive method choice can affect a woman's risk of HIV infection during sexual contact with an infected partner. In many circumstances, women cannot successfully negotiate the use of condoms with their male partner. It is therefore important that woman-controlled methods, including vaginal barrier and hormonal methods, not only provide contraceptive protection but also prevent HIV transmission.
For many years, vaginal contraceptive and lubricating products have been available worldwide and have contained the membrane cytotoxic detergent, nonoxynol-9 (N-9) as the active ingredient. N-9 serves as an effective spermicide due to its ability to disrupt cell (sperm) membrane integrity. In vitro studies also have shown that N-9 is microbicidal to various microorganisms, including HIV [5]. However, a recent randomized controlled trial showed that N-9 doubled the risk of HIV-1 infection compared to placebo; risk was especially increased in those women who used N-9 more than 3.5 times per day and who also had disruption of the vaginal epithelium [6]. This finding suggests that N-9 can affect vaginal epithelial integrity when used frequently, thereby increasing the risk of HIV transmission.
Multiple studies have been performed to further understand the relationship, if any, between N-9 exposure and HIV transmission [7], [8], [9]. Most of these studies have concentrated on the effects of N-9 on either cervical or vaginal epithelium. In the human, frequent use of N-9 has been associated with vaginal irritation and ulceration [10], [11], [12], [13]. In addition, human studies demonstrate that vaginal epithelial macrophages and Langerhans' cells are potential targets for HIV infection and could serve as HIV host cells [14]. Furthermore, multiple vaginal applications of N-9 have been shown to alter the profile of cytokines, chemokines and other inflammatory regulators in human cervico-vaginal secretions, which may predispose cells to HIV infection [15].
Using volunteer women as test subjects, we recently demonstrated that even without intercourse, intravaginal spermicide migrates from the vaginal canal into the endocervix and the lower uterine segment shortly after insertion [16]. Hence, it is possible that seminal fluid and pathogens may migrate to the upper reproductive tract as well. We hypothesized that the presence of spermicide within these regions of the upper reproductive tract results in either an inflammatory response within the epithelium, or disruption of the epithelium. These responses could place target cells in direct contact with HIV and predispose women to an increased risk of HIV transmission. The objective of the present study was to use an animal model to test the hypothesis that exposure to spermicides such as N-9 can result in alterations of the uterine epithelium that could result in increased susceptibility to HIV transmission.
Section snippets
Animals
Six-week-old, CF-1 female mice (Harlan Sprague-Dawley, Indianapolis, IN, USA) and 3–12-month-old B6D2F1/J male mice (Jackson Laboratory, Bar Harbor, ME, USA) were used. All animals were maintained in accordance with the National Academy of Science Guide for the Care and Use of Laboratory Animals, with a controlled light schedule (14 L:10 D) and temperature range. The experimental protocols were approved by the University of Pennsylvania Institutional Animal Care and Use Committee.
Agents
Three
Effects of vaginal N-9 on uterine epithelial histology
Within 24 h, exposure to intravaginal N-9 (3.5%) resulted in focal absence of the uterine epithelium proximal to the cervix (Table 1). Hemorrhage and necrosis also were observed extending into the underlying endometrial stroma. The uterine epithelium distal to the cervix had no discernible histological change. Uterine sections from mice exposed to intravaginal water and K-Y jelly were identical to uterine sections from untreated mice.
Effects of direct N-9 exposure on uterine epithelial histology
With direct injection of agent, PMNs, dilation of the uterine
Discussion
While the main portal of entry of HIV in women during heterosexual intercourse might be the vagina and cervix, these areas may not be the only sites of HIV entry. Little attention has been paid to the possible transmission of HIV across the epithelium of the female upper reproductive tract. The simple columnar and underlying secretory glandular epithelium is well documented to be susceptible to sexually transmitted infections (STIs) [20]. Compared to the squamous epithelium of the lower genital
Acknowledgements
The authors would like to thank Dr. Daniel Malamud and Amy Hummel for their critical reading of the manuscript. This work was supported by NIH Grant PO1 A1137829 (K.T.B.) and a grant from the Mellon Reproductive Biology Centers Program (C.J.W.).
References (24)
- et al.
Effectiveness of COL-1492, a nonoxynol-9 vaginal gel, on HIV-1 transmission in female sex workersa randomized controlled trial
Lancet
(2002) - et al.
Effects of multiple applications of benzalkonium chloride and nonoxynol-9 on the vaginal epithelium in the pigtailed macaque (Macaca nemestrina)
Am J Obstet Gynecol
(1999) - et al.
Comparison of spermicide on vulvar, vaginal, and cervical mucosa
Contraception
(1996) - UNAIDS. AIDS epidemic update, December...
- Center for Disease Control and Prevention. (August 4, 2000) “Dear colleague” letter: nonoxynol-9 trial—the...
The AIDS epidemic
N Engl J Med
(1999)Infection with the human immunodeficiency virus type 2
Ann Intern Med
(1993)- et al.
Female-controlled methods to prevent sexual transmission of HIV
AIDS
(1996) - et al.
Efficacy of nonoxynol-9 contraceptive sponge use in preventing heterosexual acquisition of HIV in Nairobi prostitutes
JAMA
(1992) - et al.
Condom and nonoxynol-9 use and the incidence of HIV in serodiscordant couples in Zambia
Int J STD AIDS
(1997)
A dosing study of nonoxynol-9 and genital irritation
Int J STD AIDS
Safety study of nonoxynol-9 as a vaginal microbicideevidence of adverse effects
J AIDS
Cited by (31)
ZB-06, a vaginal film containing an engineered human contraceptive antibody (HC4-N), demonstrates safety and efficacy in a phase 1 postcoital test and safety study
2023, American Journal of Obstetrics and GynecologyA phase I randomized safety study of a single-size silicone rubber diaphragm used with or without a lactic-acid-containing diaphragm gel
2019, ContraceptionCitation Excerpt :The primary objective of the present study was to assess safety (treatment emergent adverse events (AEs)) and mucosal endpoints associated with mucosal susceptibility to HIV) of the novel gel versus hydroxyethylcellulose (HEC) universal placebo gel, each delivered by the study diaphragm during two 7-day periods of daily use, with and without intercourse. We chose to assess colposcopy [7], lower genital tract histology [8,9], microbiota [10,11], select secreted immune mediators and genital tract lymphocytes [12], as these endpoints are known to be significantly altered with N-9 use, HIV activation invitro [13] and or HIV seroconversion [14–16]. We selected universal HEC placebo gel as the non-inflammatory control gel.
Multipurpose tenofovir disoproxil fumarate electrospun fibers for the prevention of HIV-1 and HSV-2 infections in vitro
2017, International Journal of PharmaceuticsCitation Excerpt :Studies have shown that increased expression of cytokines such as IL-6, IL-8, as well as IL-1α and β is strongly associated with increased susceptibility to HIV infection (Arnold et al., 2016; Doncel et al., 2004). Nonoxynol-9, once a promising microbicide candidate against HIV, was shown to increase the rate of HIV infection in clinical studies due to its pro-inflammatory properties and disruption of the reproductive epithelium (Dayal et al., 2003; Fichorova et al., 2001). Therefore, it is critical that any active agents or delivery vehicles used as a microbicide must minimally induce pro-inflammatory cytokines.
Innate and adaptive anti-HIV immune responses in the female reproductive tract
2013, Journal of Reproductive ImmunologyCitation Excerpt :For example, the spermicide/microbicide Nonoxynol-9, which leads to increased HIV infection, causes rapid exfoliation and loss of uterine, vaginal, and rectal epithelial cell sheets, thus exposing the underlying stroma (Krebs et al., 2000; Phillips et al., 2000; Jain et al., 2005; Cone et al., 2006). Nonoxynol-9 further alters the phenotype of regenerating uterine epithelial cells, causing them to transition from columnar to cuboidal epithelial cells (Dayal et al., 2003). Sexually transmitted pathogens such as HSV2 infect FRT epithelial cells and, as part of their lytic cycle, cause cell death and ulcerations through which viruses can penetrate into the FRT stroma (Horbul et al., 2011).
Mucosal integrity and inflammatory markers in the female lower genital tract as potential screening tools for vaginal microbicides
2011, ContraceptionCitation Excerpt :Histology was evaluated because prior work documented rapid movement of N-9 into the upper female reproductive tract after vaginal insertion [20]. Further, mouse and human explant models show histologic changes with N-9 exposure [13,21]. In this study, light microscopy detected no significant histologic changes or patterns of inflammatory cells in the endometrium.
Development of an in vitro alternative assay method for vaginal irritation
2011, ToxicologyCitation Excerpt :However, many of the new vaginal antimicrobial agents are cytotoxic and cause vaginal irritation, particularly, when used at higher doses (Zaneveld et al., 2002; Stafford et al., 1998; Roddy et al., 1993). In mice, intravaginal and intrauterine administration of the commonly used spermicide, nonoxynol-9 (N9), resulted in uterine epithelial sloughing or complete epithelial loss (Dayal et al., 2003; Phillips et al., 2000). Such irritation of the vaginal mucosa can increase the risk of acquiring STI pathogens such as the human herpes simplex virus (HSV) and HIV-1 in sexually active women (Mansergh et al., 2002).
- ☆
Part of this work has been presented previously at the 49th Annual Meeting of the Society for Gynecologic Investigation, March 21–23, 2002. Los Angeles, California. Presentation entitled: Contraceptive Gel Exposure Results in Inflammatory Cell Infiltration in Uterine Epithelium in the Mouse (abstract #876) and Microbicides 2002 Conference, May 12-15, 2002. Antwerp, Belgium. Presentation entitled: Nonoxynol-9 Exposure Results in Transient Loss of the Uterine Epithelium (abstract #A-171).2
- 2
Current affiliation: Division of Fertility and IVF, Dept of OB/GYN, The George Washington University, 2150 Pennsylvania Ave., NW, Washington, DC 20037.
- 2
Current affiliation: Division of Fertility and IVF, Dept of OB/GYN, The George Washington University, 2150 Pennsylvania Ave., NW, Washington, DC 20037.