The molecular basis of nonoxynol-9-induced vaginal inflammation and its possible relevance to human immunodeficiency virus type 1 transmission

Local cytokine and inflammatory responses to candidate vaginal adjuvants in mice

The current study was undertaken to explore the correlation of adjuvanticity and local inflammatory response elicited in the murine vagina and the draining lymph nodes following local administration of two candidate vaginal adjuvants, Toll like receptor (TLR) 9 agonist CpG ODN, and a non-TLR targeting molecule alpha-galactosylceramide (alpha-GalCer). Using real-time PCR array analysis, we could show that a group of 13 common cytokine genes are activated in the vagina within 24h after vaginal administration of these adjuvants, including Ccl2, Ccl7, Ccl12, Ccl19, Ccl20, Ccl22, Cxcl1, Cxcl5, Il10 and the Th1-inducing molecules Ifng, Cxcl9, Cxcl10 and Cxcl11. A high degree of inflammation in and damage to the epithelium was exclusively observed in the vagina of the CpG ODN treated mice, which was reversed within 48h. These results indicate that there is a group of common genes that correlate with the adjuvanticity of CpG ODN and alpha-GalCer in the vagina, and that alpha-GalCer induces less of local inflammatory reactions in the murine vagina compared to CpG ODN.

Comparative study on the spermicidal activity of organic solvent fractions from hydroethanolic extracts of Achyranthes aspera and Stephania hernandifolia in human and rat sperm

BACKGROUND

This study was conducted to determine the most effective fraction of the hydroethanolic (water:ethanol, 1:1) extracts of Stephania hernandifolia leaves and Achyranthes aspera roots (in a composite manner at a ratio of 1:3, respectively) that will provide maximum spermicidal activity in human and rat spermatozoa out of five different ratios (1:1, 1:3, 1:7, 3:1 and 7:1) that have been studied in pilot experiments.

STUDY DESIGN

n-Hexane, chloroform and ethyl acetate fractions of the hydroethanolic (1:1) extracts of S. hernandifolia and A. aspera were mixed at 1:3. Different concentrations were tested for sperm immobilization, sperm viability, acrosome status, 5'-nucleotidase activity and nuclear chromatin decondensation using human and rat spermatozoa for the selection of the most effective concentration.

RESULTS

Out of three fractions of the hydroethanolic (1:1) extracts of the said plants, the n-hexane fraction was most effective, and the chloroform fraction exhibited minimum activity for this purpose. At a concentration of 0.1 g/mL hexane fraction, all sperm of the human sample were immobilized immediately (within 20 s). In case of the rat sample, all epididymal spermatozoa were immobilized immediately (within 20 s) by treatment with hexane fraction at a concentration of 0.004 g/mL. All human sperm were found to be nonviable within 20 min. The activity of acrosome enzymes was reduced, and significant release of 5'-nucleotidase (a plasma membrane marker) into the surrounding medium was noted after treatment with 0.1 g/mL hexane fraction, indicating that the hexane fraction affected the cytoarchitecture of the sperm plasma membrane. The maximum number of human sperm failed to decondense when treated with 0.1 g/mL hexane fraction, and sperm motility was also irreversible. The hexane fraction was tested in rats as vaginal contraceptive and showed 100% efficacy, indicating its potential for development as vaginal contraceptive.

CONCLUSION

The findings indicate that, among the different fractions, the hexane fraction of the hydroethanolic extracts of the two plants produced the most effective spermicidal activity and can be considered as vaginal contraceptive.

Disruption of tight junctions by cellulose sulfate facilitates HIV infection: model of microbicide safety

BACKGROUND

The lack of biomarkers that are predictive of safety is a critical gap in the development of microbicides. The present experiments were designed to evaluate the predictive value of in vitro models of microbicide safety.

METHODS

Changes in the epithelial barrier were evaluated by measuring transepithelial electrical resistance (TER) after exposure of human epithelial cells to candidate microbicides in a dual-chamber system. The significance of observed changes was addressed by challenging cultures with human immunodeficiency virus (HIV) and measuring the ability of virus to cross the epithelium and infect target T cells cultured in the lower chamber.

RESULTS

Exposure to nonoxynol-9 (N-9) or cellulose sulfate (CS), but not 9-[2-(phosphonomethoxy)propyl]adenine (also referred to as tenofovir) or PRO2000, resulted in a rapid and sustained reduction in TER and a marked increase in HIV infection of T cells cultured in the lower chamber. Moreover, CS triggered nuclear factor kappaB activation in peripheral blood mononuclear cells and increased HIV replication in chronically infected U1 cells.

CONCLUSIONS

Epithelial barrier disruption and enhanced viral replication may have contributed to the increased risk of HIV acquisition observed in phase 3 trials of N-9 and CS. Expansion of in vitro safety testing to include these models would provide a more stringent preclinical assessment of microbicide safety and may prove to be more predictive of clinical outcomes.

Novel approaches in fighting herpes simplex virus infections

The development of novel strategies to eradicate herpes simplex virus (HSV) is a global public health priority. While acyclovir and related nucleoside analogues provide successful modalities for treatment and suppression, HSV remains highly prevalent worldwide and is a major cofactor fueling the HIV epidemic. HSV is the predominant cause of genital ulcerative disease, and neonatal and sporadic infectious encephalitis. Asymptomatic shedding, which occurs more frequently than previously appreciated, contributes to viral transmission. Acyclovir resistance may be problematic for immunocompromised patients and highlights the need for new safe and effective agents. Ideally, vaccines to prevent infection, drugs to inhibit the establishment of or reactivation from latency, or vaginal microbicides to prevent sexual and perinatal transmission are needed to control the epidemic. This review summarizes current therapeutic options and strategies in development.

Microbicidal spermicide or spermicidal microbicide?

Vaginal contraception, the oldest method of fertility regulation that remained virtually forgotten for a few decades has recently come under focal review due to an increase in STDs and HIV infections worldwide. Today it is being considered very strongly that a conceptual microbicidal spermicide can tender protection against pregnancy as well as STDs (including AIDS), simultaneously. However the two activities (spermicidal and microbicidal) need to be integrated in vaginal preparations, as many women across the world may be concerned more about the unwanted pregnancy rather than the STI during a coital act. A strong detergent like nonoxynol-9 (N-9) has been used as a spermicide in many local contraceptive preparations and studies have shown that it also exhibits significant microbicidal activity in vitro. However, recent clinical trials have shown that detergent spermicides do not provide any protection against STDs and AIDS but may in fact even promote their transmission. This anomaly has largely been attributed to their surfactant nature that irritates the vagina and kills the normal vaginal flora making it more susceptible to STD infections. An urgent need for a suitable non-detergent spermicide has thus emerged to replace N-9 in local contraceptive preparations. Anticipating the potential of spermicide-based vaginal contraceptives in the reproductive health of women, a large number of synthetic, non-detergent molecules were designed and evaluated at this Institute over recent years. Simultaneously, a number of natural products from terrestrial plants and marine flora/fauna were also evaluated for spermicidal activity. A local contraceptive preparation incorporating the active ingredient from the fruit pericarp of Sapindus mukorossi has successfully completed Phase III clinical trials in India and is ready for marketing. Recent studies have indicated that in comparison to N-9, this ingredient is much less toxic to Lactobacillus spp. and effectively inhibits the growth of Trichomonas vaginalis in vitro. Other candidate spermicides/microbicides under development worldwide have been reviewed briefly.

Safety analysis of the diaphragm in combination with lubricant or acidifying microbicide gels: effects on markers of inflammation and innate immunity in cervicovaginal fluid

OBJECTIVE

Diaphragms are being considered for use with vaginal microbicide gels to provide enhanced protection against sexually transmitted pathogens. The purpose of this study was to determine whether use of a diaphragm with microbicide or placebo gel causes cervicovaginal inflammation or perturbations in cervicovaginal immune defense.

METHOD OF STUDY

Eighty-one non-pregnant women were randomized into three groups and instructed to use Milex (CooperSurgical, Inc., Trumbull, CT, USA)diaphragms overnight for 14 days in combination with one of the two acid-buffering microbicide gels [ACIDFORM (Instead Inc., La Jolla, CA, USA) or BufferGel(trade mark) (BG; ReProtect Inc., Baltimore, Maryland)] or placebo gel (K-Y Jelly); Personal Products Inc., Raritan, NJ, USA). Cervicovaginal lavages (CVLs) were performed prior to study entry and on days 8 and 16. Nine soluble mediators of vaginal inflammation or immune defense were measured in CVLs by Bio-Plex or ELISA.

RESULTS

Use of diaphragms with placebo or microbicide gel was not associated with increased levels of inflammation markers. Concentrations of secretory leukocyte protease inhibitor (SLPI) were markedly reduced in the BG group.

CONCLUSION

Daily use of a diaphragm with placebo or acidifying microbicide gel did not cause cervicovaginal inflammation. However, diaphragm/BG use was associated with markedly reduced levels of SLPI, an important mediator of innate immune defense. Further studies are warranted to establish the safety of diaphragm/microbicide gel combinations.

Chlamydia trachomatis laboratory strains versus recent clinical isolates: implications for routine microbicide testing

A topical microbicide that women can use to prevent sexually transmitted diseases (STDs) is essential, and many microbicide candidates are being tested for activity against human immunodeficiency virus and other STDs, including Chlamydia trachomatis. Screening assays for assessing the activity of microbicides against C. trachomatis are typically done with laboratory-adapted strains, but it is possible that recent clinical isolates may have different susceptibilities to microbicides, as has been seen with Neisseria gonorrhoeae and Lactobacillus spp. (B. J. Moncla and S. L. Hillier, Sex. Transm. Dis. 32:491-494, 2005). We utilized three types of microbicides to help define this aspect of our assay to test microbicides against C. trachomatis in vitro. To simulate conditions of transmission, we used an assay that we previously developed in which we exposed chlamydial elementary bodies to microbicides prior to contact with epithelial cells. We first determined the toxicity of microbicides to the cells used to culture Chlamydia trachomatis in the assay and, if necessary, modified the assay to eliminate toxicity at the concentrations tested. We compared the sensitivities of recent clinical isolates of Chlamydia trachomatis versus laboratory strains of the same serovar and found major differences in sensitivity to nonoxynol-9 (non-9), but only minor differences were seen with the other microbicides. We thus conclude that when assessing activity of potential topical microbicides versus the obligate intracellular bacteria C. trachomatis, the use of recent clinical isolates may not be necessary to draw a conclusion about a microbicide's effectiveness. However, it is important to keep in mind that differences (like those seen with non-9) are possible and that clinical isolates could be included in later stages of testing.

Polyanionic microbicides modify Toll-like receptor-mediated cervicovaginal immune responses

Topical microbicides are being developed as a preventative approach to reduce the sexual transmission of human immunodeficiency virus type 1 (HIV-1) and other infections. For them to be efficacious, it is believed that they should avoid inducing inflammation while allowing the vaginal epithelium to initiate protective Toll-like receptor (TLR)-mediated innate responses against pathogens. In this study, human cervical and vaginal epithelial cells were exposed to polyanionic HIV entry inhibitors and the following synthetic TLR ligands: (i) the bacterial lipoprotein Pam(3)CSK(4), binding cell surface TLR1/TLR2; (ii) macrophage activating lipopeptide 2 (MALP-2), binding cell surface TLR2/TLR6; and (iii) the viral double-stranded RNA analog poly(I:C), recognized by intracellular TLR3. Cell activation was assessed by nuclear factor kappaB (NF-kappaB) reporter gene transactivation and cytokine production. In spite of enhancing TLR-triggered NF-kappaB activation, the polyanionic microbicide compounds dextran sulfate and polystyrene sulfonate significantly inhibited TLR-mediated cytokine production. They decreased cytokine mRNA and protein levels of proinflammatory (interleukin-8 [IL-8] and IL-1beta) and antiviral (beta interferon) cytokines following epithelial cell stimulation with Pam(3)CSK(4), MALP-2, or poly(I:C). These activities were associated with the sulfate/sulfonate moieties of the polyanionic compounds, since the unsulfated dextran control did not show any effects. Our data demonstrate that these microbicide compounds are capable of selectively interfering with TLR-mediated epithelial responses at different points in their signaling pathways and underscore the importance of expanding the assessment of microbicide compatibility with vaginal innate immune function. Further studies are warranted to determine the impact of this interference on HIV-1 transmission risk.

Glycerol monolaurate does not alter rhesus macaque (Macaca mulatta) vaginal lactobacilli and is safe for chronic use

Glycerol monolaurate (GML) is a fatty acid monoester that inhibits growth and exotoxin production of vaginal pathogens and cytokine production by vaginal epithelial cells. Because of these activities, and because of the importance of cytokine-mediated immune activation in human immunodeficiency virus type 1 (HIV-1) transmission to women, our laboratories are performing studies on the potential efficacy of GML as a topical microbicide to interfere with HIV-1 transmission in the simian immunodeficiency virus-rhesus macaque model. While GML is generally recognized as safe by the FDA for topical use, its safety for chronic use and effects on normal vaginal microflora in this animal model have not been evaluated. GML was therefore tested both in vitro for its effects on vaginal flora lactobacilli and in vivo as a 5% gel administered vaginally to monkeys. In vitro studies demonstrated that lactobacilli are not killed by GML; GML blocks the loss of their viability in stationary phase and does not interfere with lactic acid production. GML (5% gel) does not quantitatively alter monkey aerobic vaginal microflora compared to vehicle control gel. Lactobacilli and coagulase-negative staphylococci are the dominant vaginal aerobic microflora, with beta-hemolytic streptococci, Staphylococcus aureus, and yeasts sporadically present; gram-negative rods are not part of their vaginal flora. Colposcopy and biopsy studies indicate that GML does not alter normal mucosal integrity and does not induce inflammation; instead, GML reduces epithelial cell production of interleukin 8. The studies suggest that GML is safe for chronic use in monkeys when applied vaginally; it does not alter either mucosal microflora or integrity.

Vaginal microbicides: where are we and where are we going?

The epidemic of HIV has catalyzed the need for safe and effective prevention methods, particularly for women. Vaginal microbicides have been targeted because these methods can be controlled by women themselves. Microbicides have focused on preventing HIV as well as other sexually transmitted infections, because the acquisition of HIV is enhanced by the presence of many infections. Although many products show promise in preclinical trials, safety remains paramount. The importance of safety was exemplified by the nonoxynol-9 studies which showed actual harm. This experience catalyzed the development of criteria that should be used as safety standards in trials, including immune markers of the cervical epithelium, and colposcopy standards. Unfortunately, immune markers are in their infant stages of development and reliability and validity checks remain large challenges. There have been four recent phase IIb/III trials that had disappointing results. However, these trials offer an opportunity to develop new preclinical models and biomarkers. The search for new microbicides remains critical. Current microbicides in trials can be categorized into vaginal defense enhancers (which help maintain the vaginal pH or facilitate the colonization of vaginal lactobacilli); surfactants (or detergents) which disrupt viral membranes; HIV entry inhibitors; and HIV reverse transcriptase inhibitors. Even with a good product, acceptance by both partners will be essential for its success, and lack of acceptance is often not evident until large trials are completed.

Biomarkers of leukocyte traffic and activation in the vaginal mucosa

Development of novel vaginal spermicides and anti-human immunodeficiency virus (HIV) microbicides requires careful assessment of their potential to recruit and activate CD4+ HIV-1 host cells in the female genital tract mucosa, two events that facilitate HIV-1 infection. Leukocyte traffic and activation are mediated by proinflammatory cytokines and chemokines, e.g. interleukin (IL)-1, IL-6 and IL-8, which have been detected in vaginal secretions in association with epithelial damage and infections. These proinflammatory mediators, however, have bidirectional, destructive as well as beneficial, effects on the mucosal barrier, and may be counterbalanced by endogenous inhibitors. Here we propose additional biomarkers for the evaluation of compound-induced cervicovaginal mucosal inflammation. Displaying different temporal patterns of detection, the levels of soluble E-selectin, vascular adhesion molecule-1, CD14 and myeloperoxidase in vaginal secretions reflected the mucosal leukocyte reaction to proinflammatory compounds being evaluated for safety in an improved rabbit vaginal irritation model. These biomarkers, which were also detected in human vaginal secretions, may be used to enhance the characterization of mucosal safety of vaginally applied compounds, both in animal as well as clinical studies.

Surfactants as microbicides and contraceptive agents: a systematic in vitro study

Background

The urgent need for cheap and easy-to-use protection against both unwanted pregnancies and sexually transmitted diseases has stimulated considerable interest in the use of surfactants as microbicides, anti-viral, and contraceptive agents in recent years. In the present study we report a systematic in vitro evaluation of the microbicidal, anti-viral and contraceptive potential of cationic, anionic, zwitterionic, and non-ionic surfactants.

Methodology/Principal Findings

Toxicity was evaluated in mammalian columnar epithelial (MDCK) cells, human sperm cells, Candida albicans, Escherichia coli, Pseudomonas aeruginosa, Neisseria gonorrhoeae, Streptococcus agalactiae and Enterococcus faecalis. The inhibition of adenovirus and lentivirus infection of MDCK cells was also tested. A homologous series of cationic surfactants, alkyl-N,N,N-trimethylammonium bromides (C_nTAB), with varying alkyl chains were shown to be bactericidal and fungicidal at doses that were related to the surfactant critical micelle concentrations (CMC), all of them at concentrations significantly below the CMC. In general, bacteria were more susceptible to this surfactant group than C. albicans and this organism, in turn, was more susceptible than MDCK cells. This suggests that the C_nTAB may be useful as vaginal disinfectants only in so far as bacterial and fungal infections are concerned. None of the surfactants examined, including those that have been used in pre-clinical studies, showed inhibition of adenovirus or lentivirus infection of MDCK cells or spermicidal activity at doses that were sub-toxic to MDCK cells.

Conclusions/Significance

The results of this study lead us to propose that systematic analysis of surfactant toxicity, such as we report in the present work, be made a mandatory pre-condition for the use of these substances in pre-clinical animal and/or human studies.

ICAM-1 expression in vaginal cells as a potential biomarker for inflammatory response

This study aimed to elucidate the mechanisms that may lead to an efficient strategy to induce a suitable host response of the vaginal mucosa upon exposure to intravaginally delivered exogenous compounds. It was hypothesized that the upregulation of intercellular adhesion molecule (ICAM)-1 gene expression may reflect the inflammatory response evoked by exogenous compounds. Major emphasis was placed on ethylenediamine tetraacetic acid (EDTA) which was added as a synergistic agent to conventional spermicidal agents or anti-HIV drugs. The levels of ICAM-1 mRNA were examined as a surrogate marker for inflammatory response in human vaginal epithelial cells upon exposure to EDTA or interleukin (IL)-1beta (i.e. positive control, 25 mM). The effects of estrogen on EDTA-induced ICAM-1 expression were also evaluated for the estrogen involvement in the inflammatory process of the vaginal mucosa. ICAM-1 expression in human vaginal cells (VK2/E6E7 cells) increased as EDTA concentration added to human vaginal cell lines increased. The effects of estrogen on EDTA-induced ICAM-1 expression in human vaginal epithelial cells were estrogen-concentration dependent; estrogen at lower concentrations (approximately 1-10 nM) did not affect ICAM-1 expression, whereas estrogen at higher concentrations (approximately 100 nM-1 microM) attenuated ICAM-1 expression. The influence of estrogen in ICAM-1 expression suggests the beneficial effects of estrogen on the regulation of vaginal homeostasis. Identification and quantification of specific surrogate markers for the inflammatory response evoked by exogenous compounds and their regulation by estrogen will lead to an efficient strategy against sexually transmitted diseases including AIDS.

Structural details and composition of Trichomonas vaginalis lipophosphoglycan in relevance to the epithelial immune function

Trichomonas vaginalis causes the most common non-viral sexually transmitted infection linked to increased risk of premature birth, cervical cancer and HIV. This study defines molecular domains of the parasite surface glycoconjugate lipophosphoglycan (LPG) with distinct functions in the host immunoinflammatory response. The ceramide phospho-inositol glycan core (CPI-GC) released by mild acid had Mr of approximately 8,700 Da determined by MALDI-TOF MS. Rha, GlcN, Gal and Xyl and small amounts of GalN and Glc were found in CPI-GC. N-acetyllactosamine repeats were identified by endo-beta-galactosidase treatment followed by MALDI-MS and MS/MS and capLC/ESI-MS/MS analyses. Mild acid hydrolysis led to products rich in internal deoxyhexose residues. The CPI-GC induced chemokine production, NF-kappaB and extracellular signal-regulated kinase (ERK)1/2 activation in human cervicovaginal epithelial cells, but neither the released saccharide components nor the lipid-devoid LPG showed these activities. These results suggest a dominant role for CPI-GC in the pathogenic epithelial response to trichomoniasis.

Evaluation of local tolerance of the antiretroviral spermicide (WHI-07)-loaded gel-microemulsion in the porcine female reproductive tract

The local tolerance of the antiretroviral spermicide, WHI-07 (5-bromo-6-methoxy-5,6-dihydro-3'-azidothymidine-5'-(p-bromophenyl)-methoxyalaninyl phosphate)-loaded gel-microemulsion was evaluated in a physiologically relevant and sensitive porcine model. Gilts (Duroc) in nonestrus stages of the reproductive cycle received either a single or a daily intravaginal application of 2.0% WHI-07 via a gel-microemulsion for 6 days. Cervicovaginal lavage (CVL) fluid was obtained for up to 72 h after a single exposure and the cellular profile and levels of inflammatory cytokines (IL-1beta, IL-8, IFN-gamma and TNF-alpha) were quantitated by flow cytometry and chemiluminescence-based multiplex immunoassay, respectively. The reproductive tract (vagina, cervix, uteri and Fallopian tubes) harvested on day 7 was scored histologically for evidence of mucosal irritation using a new scoring criterion for ten histological endpoints that reflect pathological changes in the epithelial/ subepithelial and vascular/perivascular compartments. When compared with irritant reactions caused by the detergent-type spermicide, benzalkonium chloride (BZK), the scatter profile of CVL immune cells and basal levels of proinflammatory cytokines (IL-1beta, IL-8, IFN-gamma and TNF-alpha) in CVL fluid were unaffected by intravaginal exposure to 2% WHI-07. Unlike BZK, endpoint histology of the proximal and distal regions of the reproductive tract from gilts treated with 2.0% WHI-07 via gel-microemulsion for 6 days did not result in mucosal irritation or alteration in the epithelium, subepithelium/lamina propria, vessels/perivascular tissues and underlying/surrounding muscles. Based on surrogate markers for inflammation, leukocyte profile and histologic data for local tolerance, repeated intravaginal administration of WHI-07 via gel-microemulsion as a prophylactic contraceptive is unlikely to cause vaginal irritation.

Integrating multidimensional HIV prevention programs into healthcare settings

Effective secondary prevention programs to reduce HIV transmission risk-relevant behaviors among HIV-infected individuals must go beyond the traditional, common sense prevention components to develop biomedically and epidemiologically informed behavioral interventions as part of comprehensive, integrated, multidisciplinary HIV care. Incorporating and expanding on the Serostatus Approach to Fighting the Epidemic, a five-pronged strategy set forth by the Centers for Disease Control and Prevention in 2001, we discuss recent findings from the biomedical sciences on viral and host factors that influence infectiousness to support the idea that the most proactive prevention programs will explicitly integrate biomedical interventions and approaches designed to reduce infectiousness, and thus the sexual transmission of HIV. Based on studies of emerging and spreading drug-resistant HIV variants, we have posited the potential development of biodisparity as the biological entrenchment of disparities in socioeconomic status, access to care, and HIV risk-relevant behaviors that differentially affect minorities living with HIV in the US. It is clear that creative approaches based on an expanded behavioral medicine interface with the latest HIV biomedical and epidemiological research are needed to enhance the efficacy of HIV secondary prevention.

As the world grows: contraception in the 21st century

Contraceptives that are readily available and acceptable are required in many poorer countries to reduce population growth and in all countries to prevent maternal morbidity and mortality arising from unintended pregnancies. Most available methods use hormonal steroids or are variations of barrier methods. Reports from several fora over the last 12 years have emphasized the number of unwanted pregnancies and resultant abortions, which indicate an unmet need for safe, acceptable, and inexpensive contraceptive methods. This unmet need can be assuaged, in part, by development of new nonhormonal contraceptive methods. This Review addresses the contribution that the "omic" revolution can make to the identification of novel contraceptive targets, as well as the progress that has been made for different target molecules under development.

Porphyromonas gingivalis induces CCR5-dependent transfer of infectious HIV-1 from oral keratinocytes to permissive cells

Background

Systemic infection with HIV occurs infrequently through the oral route. The frequency of occurrence may be increased by concomitant bacterial infection of the oral tissues, since co-infection and inflammation of some cell types increases HIV-1 replication. A putative periodontal pathogen, Porphyromonas gingivalis selectively up-regulates expression of the HIV-1 coreceptor CCR5 on oral keratinocytes. We, therefore, hypothesized that P. gingivalis modulates the outcome of HIV infection in oral epithelial cells.

Results

Oral and tonsil epithelial cells were pre-incubated with P. gingivalis, and inoculated with either an X4- or R5-type HIV-1. Between 6 and 48 hours post-inoculation, P. gingivalis selectively increased the infectivity of R5-tropic HIV-1 from oral and tonsil keratinocytes; infectivity of X4-tropic HIV-1 remained unchanged. Oral keratinocytes appeared to harbor infectious HIV-1, with no evidence of productive infection. HIV-1 was harbored at highest levels during the first 6 hours after HIV exposure and decreased to barely detectable levels at 48 hours. HIV did not appear to co-localize with P. gingivalis, which increased selective R5-tropic HIV-1 trans infection from keratinocytes to permissive cells. When CCR5 was selectively blocked, HIV-1 trans infection was reduced.

Conclusion

P. gingivalis up-regulation of CCR5 increases trans infection of harbored R5-tropic HIV-1 from oral keratinocytes to permissive cells. Oral infections such as periodontitis may, therefore, increase risk for oral infection and dissemination of R5-tropic HIV-1.

Preclinical evaluation of a dual-acting microbicidal prodrug WHI-07 in combination with vanadocene dithiocarbamate in the female reproductive tract of rabbit, pig, and cat

The mucosal safety of the combination antiretroviral spermicide,WHI-07 [5-bromo-6-methoxy-5,6-dihydro-3'-azidothymidine-5'-(p-bromophenyl)-methoxy alaninyl phosphate] and vanadocene dithiocarbamate (VDDTC), was evaluated in 3 different animal models. Twenty-seven NZW rabbits in four subgroups were exposed intravaginally to a gel-microemulsion (GM) with and without three dose levels of WHI-07 plus VDDTC (0.5+0.06%, 1.0+0.12% and 2.0+0.25%) or 4% nonoxynol-9 (N-9; Conceptrol) for 14 consecutive days. Ten nonestrus gilts (Duroc) in three subgroups received either a single or daily intravaginal application of GM with and without 2.0% WHI-07 plus 0.25% VDDTC or 2.0% benzalkonium chloride (BZK)-containing gel for 6 and 4 consecutive days, respectively. Five cats received a single intravaginal application of GM incorporating 2.0% WHI-07 plus 0.25% VDDTC. Genital tract histopathology was performed in the pig and rabbit at the end of dosing period but after 18 weeks post-dosing in the cat. Porcine cervicovaginal lavage (CVL) fluid was obtained for up to 72 hours after a single exposure and changes in the levels of inflammatory cytokines (IL-1beta, IL-8, IFN-gamma, and TNF-alpha) were quantitated by a multiplexed chemiluminescence-based immunoassay. Rabbit vaginal tissues were evaluated for localized cellular inflammation and in situ apoptosis by immunohistochemical staining for CD45, nuclear factor (NF)-kappa B, and terminal deoxynucleotidyl transferase-mediated FITC-deoxyuridine triphosphate nick-end labeling (TUNEL) using confocal laser scanning microscopy (CLSM), respectively. Vanadium content in selected organs and body fluids from rabbits and pigs was determined by atomic absorption spectroscopy. When compared with 4% N-9 (total irritation score 13-14 out of a possible 16), none of the rabbits given WHI-07 plus VDDTC intravaginally, developed histological alterations such as epithelial erosion, edema, leukocyte influx or vascular congestion characteristic of inflammation (total irritation score 4-6). CD45 and NF-kappa B immunoreactivity was limited to cells within the vascular lumen of both control and WHI-07 plus VDDTC-treated vaginal tissues. TUNEL assay revealed lack of increased apoptotic cells in vaginal mucosa exposed to increasing concentrations of WHI-07 plus VDDTC. Basal levels of proinflammatory cytokines (IL-1beta, IL-8, IFN-gamma and TNF-alpha) in porcine CVL were unaffected by intravaginal exposure to WHI-07 plus VDDTC when compared with BZK used as a positive control. Endpoint histology of the reproductive tract from cats and pigs after a single or repeated intravaginal exposure to WHI-07 plus VDDTC, respectively, revealed lack of irritation/inflammation in the epithelium, subepithelium/lamina propria, vessels/perivascular tissues, and underlying/surrounding muscles. Vanadium was not preferentially incorporated into rabbit or porcine tissues and body fluids at levels above 1 microg/g. Based on comparative histologic data and surrogate markers for inflammation, repeated intravaginal administration of WHI-07 plus VDDTC via a gel-microemulsion did not result in vaginal irritation, mucosal toxicity, or systemic absorption of vanadium. Therefore, the combined use of WHI-07 and VDDTC via gel-microemulsion appears safe for topical use as a prophylactic anti-HIV microbicide.

Porcine Vagina Ex Vivo as a Model for Studying Permeability and Pathogenesis in Mucosa

The vaginal mucosa is commonly exposed to a variety of topical agents, including chemical contraceptives, drugs for the treatment of specific pathological conditions, and pathogenic microorganisms. In vitro models can provide important information regarding the penetration and efficacy of topical compounds as well as the pathogenesis of various diseases such a menstrual toxic shock syndrome. Realistic and reproducible test systems are important if new agents are to fulfill their therapeutic potential in human populations. The selection of appropriate animal species and tissue and the use of valid in vitro systems can avoid many of the shortcomings of current animal and cell culture test systems. This review provides information about the factors that should be considered when selecting the best model to study the permeability of the human vagina. The characteristics of an ex vivo porcine model are explored and the validity of this model is demonstrated in terms of its histology, ultrastructure and composition and organization of the permeability barrier; data indicate excellent correlation of permeability and tissue response between human and porcine vaginal tissue.

Lime Juice as a Candidate Microbicide? An Open-Label Safety Trial of 10% and 20% Lime Juice Used Vaginally

OBJECTIVE

Lime has a long history as a contraceptive and vaginal hygiene douche, and ongoing use in Africa is documented. We report on the first safety study on diluted lime juice to assess its potential as a candidate microbicide.

METHODS

Twenty-five sexually abstinent women were randomly assigned to apply a 10% or 20% concentration of lime juice or 0% (water-only) through a soaked tampon once daily for 14 consecutive days. Tests for genital infections, measurement of inflammatory biomarkers, and a colposcopy were performed before and after treatment.

RESULTS

No participant showed severe vaginal irritation. Two women developed a yeast infection after using lime juice. More than 70% of women in all groups reported side effects, most being singular, mild, and transient events. The users of 20% diluted lime juice experienced a significantly higher frequency of burning and dryness. Vaginal inflammatory biomarkers showed no significant change between preexposure and postexposure levels. The naturally low vaginal pH showed little change, and lactobacilli colonization did not decrease.

CONCLUSIONS

Lime juice up to 20% concentration has an acceptable safety profile for vaginal use. However, as new in vitro research shows that the effectiveness of lime juice to prevent HIV transmission in concentrations lower than >or=50% is unlikely and concentrations of 50% have been shown to be toxic, women should be discouraged from commencing or continuing the vaginal use of lime juice.

Mucosal safety of PHI-443 and stampidine as a combination microbicide to prevent genital transmission of HIV-1

OBJECTIVE

To investigate the in vitro and in vivo mucosal safety of a nonnucleoside reverse transcriptase (RT) inhibitor (PHI-443) and a nucleoside analogue RT inhibitor (stampidine)-based anti-HIV microbicide either alone or in combination.

DESIGN

In vitro and in vivo studies using three-dimensional vaginal epithelia integrating Langerhans cells and 16 New Zealand White rabbits, respectively.

SETTING

Research laboratory.

INTERVENTION(S)

Rabbits in groups of four were exposed intravaginally to a gel with and without 1% PHI-443, 1% stampidine, or 1% PHI-443 plus 1% stampidine for 14 days. Cytokine/chemokine release by three-dimensional co-cultures in the presence and absence of PHI-443 or stampidine.

MAIN OUTCOME MEASURES(S)

Histologic scoring of vaginal tissue for mucosal toxicity at 24 hours after dosing. Simultaneous evaluation of levels of 10 cytokines (granulocyte-macrophage colony-stimulating factor, interleukin-1 alpha, interleukin-13, macrophage inflammatory protein-1 beta, granulocyte colony-stimulating factor, interleukin-18, tumor necrosis factor-alpha, interleukin-6, interleukin-1 beta, and interferon-gamma) and 6 chemokines (epithelial neutrophil-activating peptide-78, interleukin-8, monocyte/macrophage chemoattractant protein-1, macrophage inflammatory protein-3 alpha, interferon-inducible protein-10, and regulated upon activation of normal T-cell expressed and secreted) in culture media by a multiplexed chemiluminescence-based immunoassay.

RESULT(S)

In the rabbit model, repeated intravaginal administration of PHI-443 plus stampidine via a gel formulation at concentrations nearly 2,000 and 10,000 times higher than their respective in vitro anti-HIV IC(50) values did not result in vaginal irritation. The levels of proinflammatory cytokines/chemokines secreted by multilayered human genital epithelia integrating Langerhans cells were unaffected by prolonged exposure to PHI-443 or stampidine.

CONCLUSION(S)

The combination of PHI-443 and stampidine was noncytotoxic to vaginal epithelial cells, nonirritating to vaginal mucosa, and did not induce the secretion of proinflammatory cytokines and chemokines by co-cultures of human genital epithelia and Langerhans cells. These attributes are particularly useful for the clinical development of PHI-443 and stampidine as a combination microbicide and as a prophylactic anti-HIV agent to curb genital transmission of HIV-1 by semen.

Microbicides and other topical agents in the prevention of HIV and sexually transmitted infections

According to information from UNAIDS, more than 42 million individuals are living with HIV worldwide. Most infected individuals live in developing countries where the availability of antiretroviral agents is still limited. As this pandemic is increasing largely through mucosal transmission, new methods of prevention are urgently needed. If available, agents that block HIV prior to or early after contact with mucosal epithelia would decrease the incidence of HIV infection and, therefore, potentially save millions of lives over the next few decades. Topically applied microbicides acting against HIV-1 can be subdivided into four subgroups, including agents directly inhibiting pathogens, agents acting on genital pH, agents blocking pathogen entry and replication inhibitors. In addition, microbicides might also allow fighting against other sexually transmitted infections, such as herpes simplex viruses. With concerted efforts directed towards developing efficient microbicides, topical anti-infective compounds may well become a new weapon against sexually transmitted infections, including HIV, in everyday clinical practice.

Microbicide drug candidates to prevent HIV infection

25 years after the first HIV/AIDS cases emerged in 1981, the disease continues to spread worldwide, with about 15 000 new infections every day. Although highly active antiretroviral therapy (HAART) has greatly reduced the rate of HIV infection, and the spread of the epidemic, this effect has largely been seen in developed countries. More than 90% of HIV-infected people live in developing countries, most of whom do not have access to this treatment. The development of efficient, widely available, and low-cost microbicides (gels and creams can be applied topically before sex) to prevent sexually transmitted HIV infections should be given high priority. We review different categories of microbicide drugs and lead compounds, their mechanism of action, current status of development, and progress in phase III trials.

PRO 2000 elicits a decline in genital tract immune mediators without compromising intrinsic antimicrobial activity

OBJECTIVE

Vaginal microbicides should protect against infection without disrupting the mucosal environment or its mediators of host defense. The objective of this study was to examine the effect of 14 daily applications of 0.5% PRO 2000 or placebo gel on mediators of mucosal immunity and intrinsic antimicrobial activity.

DESIGN AND METHODS

A randomized, prospective, double-blind, placebo-controlled study was conducted among 24 healthy, abstinent women. Levels of cytokines, chemokines, defensins, and other protective factors and intrinsic antimicrobial activity were determined in cervicovaginal lavage samples collected on study days 0, 7, 14, and 21.

RESULTS

No increase in pro-inflammatory cytokines was observed. Rather cytokines and protective factors including interleukin (IL)-1 receptor antagonist, immunoglobulins and human beta-defensin 2 were lower in the drug compared with the placebo group. All of the mediators returned towards baseline on day 21. Women who were cycling had lower levels of most proteins on study days 7 and/or 14 compared with women on oral contraceptives; however, the magnitude of decline was greater in women who received PRO 2000 compared with placebo gel. The reduction in protective factors was not associated with a loss in the intrinsic anti-viral (HIV or herpes simplex virus) activity or anti-bacterial activity (Escherichia coli or Staphylococcus aureus).

CONCLUSION

In contrast to experience with nonoxynol-9, PRO 2000 did not trigger an inflammatory response in cervicovaginal secretions. There was a modest reduction in mucosal immune mediators, but this loss was not associated with a reduction in intrinsic antimicrobial activity.

Relationship between plasma selenium concentrations and lower genital tract levels of HIV-1 RNA and interleukin type 1beta

OBJECTIVE

To examine the relationship between selenium nutritional status and intermediates of human immunodeficiency virus (HIV)-1 transmission.

DESIGN

Prospective cohort study.

SETTING

A study clinic at Muhimbili National Hospital, Dar es Salaam, Tanzania.

SUBJECTS

A total of 340 HIV-1-infected pregnant women with gestational ages 12-27 weeks.

METHODS

Women's plasma selenium concentrations were determined at enrollment and modeled as tertiles (tertile 1: <114 microg/l (reference); tertile 2: 114-131 microg/l; tertile 3: >131 microg/l). Cervicovaginal lavage specimens were obtained at 36 weeks of gestation to determine HIV-1 RNA and interleukin-1beta (IL-1beta) levels. In subgroup analyses, 123 women with genital tract infections at enrollment were excluded.

RESULTS

Plasma selenium concentrations >or=114 microg/l were related to increased risk of lower-genital shedding of HIV-1 RNA. Excluding women with genital tract infections strengthened the associations (relative risk (RR) tertile 2: 1.46, 95% confidence interval (CI)=1.10, 1.92; RR tertile 3: 1.39, 95% CI=1.05, 1.84). There was evidence for an association between plasma selenium concentrations >or=114 microg/l and increased HIV-1 RNA levels among the entire cohort and after excluding women with genital tract infections. There was no association between plasma selenium and IL-1beta concentrations.

CONCLUSIONS

High selenium status may lead to increased risk of genital HIV-1 shedding, but data from other studies indicate that the evidence is mixed. Results from ongoing selenium trials are awaited to clarify the impact of selenium on HIV-1-related transmission endpoints.

SPONSORSHIP

National Institute of Child Health and Human Development (NICHD R01 32257) and the Fogarty International Center (NIH D43 TW00004).

Novel disulphide esters of carbothioic acid as potent, non-detergent spermicides with low toxicity to Lactobacillus and HeLa cells in vitro

BACKGROUND

The design, synthesis, characterization and evaluation of a novel series of non-detergent spermicides has led to the discovery of two unique molecules (DSE-36 and DSE-37) that were approximately 25 times more potent spermicides than nonoxynol-9 (N-9).

METHODS

Normal human spermatozoa were used to assess the spermicidal activity (Sander-Cramer Assay), the effect on sperm-membrane integrity [hypo-osmotic swelling test (HOST)], supravital staining and scanning electron microscopy (SEM) and the induction of apoptosis [fluorescein isothiocyanate (FITC) Annexin-V and JC-1 labelling using flow cytometry] by the new class of compounds. HeLa and Lactobacillus cultures were used to assess the cytotoxicity of compounds and their compatibility to normal vaginal flora, respectively.

RESULTS

Compounds DSE-36 and DSE-37 exhibited a strong spermicidal activity [minimum effective concentration (MEC) = 0.002%], which was approximately 25 times more potent than that of N-9 and Sapindus saponins (MEC = 0.05%). As compared with surfactants, DSE-36 and DSE-37 were found to be safer at MEC towards the growth and survival of Lactobacilli and HeLa cells in vitro and to have a milder effect on sperm plasma membrane. At EC(50) both induced apoptosis in sperm cells as characterized by increased labelling with Annexin-V and decreased polarization of sperm mitochondria.

CONCLUSION

Preliminary studies have revealed that in sharp contrast to the non-specific surfactant action of N-9, DSE-36 and DSE-37 have a highly potent, mechanism-based, detrimental action on human sperm. The unique ability of these non-detergent molecules to selectively kill sperm and spare Lactobacilli and HeLa cells at MEC values much lower than that required for N-9 indicates their potential as superior ingredients for formulation into microbicidal contraceptives.

Microbicides: a new frontier in HIV prevention

Microbicides are products that can be applied to vaginal or rectal mucosal surfaces with the goal of preventing, or at least significantly reducing, the transmission of sexually transmitted infections (STIs) including HIV-1. Despite more than two decades of HIV-1 vaccine research, there is still no efficacious HIV-1 vaccine, and the scientific community appears skeptical about the short or long-term feasibility of developing a vaccine that has the ability to induce sterilizing immunity against HIV-1. In this setting, microbicide research has gathered momentum. Currently, 16 candidate microbicides are in clinical development and five products are being evaluated in large-scale Phase 2B/3 effectiveness studies. Initial data from these trials will be available within the next 2-3 years, and it is feasible that there could be one or more licensed microbicides by the end of the decade. The first generation of surfactant microbicides had a non-specific mechanism of action. However, subsequent candidate microbicides have been developed to target specific steps in the process of viral transmission. The purpose of this article is to provide an overview of microbicide development and an update on the candidate pipeline.

The impact of the use of COL-1492, a nonoxynol-9 vaginal gel, on the presence of cervical human papillomavirus in female sex workers

This study investigated the effectiveness of a nonoxynol-9 (52.5mg, 3.5%), vaginal gel (Advantage S), in the prevention of human papillomavirus (HPV) infection in female sex workers. We showed by HPV DNA determination in cervico-vaginal rinses a significant increase in multiple (>1) HPV infection in HIV-1 seropositive women compared with HIV-1 seronegative women (OR 4.0, 95% CI 1.3-11.9). We also demonstrated a significant increase in multiple HPV infections in HIV-1 seronegative women using nonoxynol-9 compared with HIV-1 seronegative women using placebo (OR 3.5 95% CI 1.0-11.8). We conclude that the use of nonoxynol-9 did not prevent genital HPV infection and could increase the virus' ability to infect or persist.

Biocompatibility of solid-dosage forms of anti-human immunodeficiency virus type 1 microbicides with the human cervicovaginal mucosa modeled ex vivo

Topical anti-human immunodeficiency virus (HIV) microbicides are being sought to reduce the spread of HIV type 1 (HIV-1) during sexual intercourse. The success of this strategy depends upon the selection of formulations compatible with the natural vaginal mucosal barrier. This study applied ex vivo-modeled human cervicovaginal epithelium to evaluate experimental solid-dosage forms of the anti-HIV-1 microbicide cellulose acetate 1,2-benzenedicarboxylate (CAP) and over-the-counter (OTC) vaginal products for their impact on inflammatory mediators regarded as potential HIV-1-enhancing risk factors. We assessed product-induced imbalances between interleukin-1alpha (IL-1alpha) and IL-1beta and the natural IL-1 receptor antagonist (IL-1RA) and changes in levels of IL-6, tumor necrosis factor alpha, IL-8, gamma interferon inducible protein 10 (IP-10), and macrophage inflammatory protein 3alpha (MIP-3alpha), known to recruit and activate monocytes, dendritic cells, and T cells to the inflamed mucosa. CAP film and gel formulation, similarly to the hydroxyethylcellulose universal vaginal placebo gel and the OTC K-Y moisturizing gel, were nontoxic and caused no significant changes in any inflammatory biomarker. In contrast, OTC vaginal cleansing and contraceptive films containing octoxynol-9 or nonoxynol-9 (N-9) demonstrated similar levels of toxicity but distinct immunoinflammatory profiles. IL-1alpha, IL-1beta, IL-8, and IP-10 were increased after treatment with both OTC vaginal cleansing and contraceptive films; however, MIP-3alpha was significantly elevated by the N-9-based film only (P < 0.01). Although both films increased extracellular IL-1RA, the cleansing film only significantly elevated the IL-1RA/IL-1 ratio (P < 0.001). The N-9-based film decreased intracellular IL-1RA (P < 0.05), which has anti-inflammatory intracrine functions. This study identifies immunoinflammatory biomarkers that can discriminate between formulations better than toxicity assays and should be clinically validated in relevance to the risk of HIV-1 acquisition.

Trichomonas vaginalis lipophosphoglycan triggers a selective upregulation of cytokines by human female reproductive tract epithelial cells

Trichomonas vaginalis is one of the most common nonviral sexually transmitted human infections and, worldwide, has been linked to increased incidence of human immunodeficiency virus type 1 transmission, preterm delivery, low birth weight, cervical cancer, and vaginitis. The molecular pathways that are important in initiating host inflammatory and immune responses to T. vaginalis are poorly understood. Here we report interactions of human cervicovaginal epithelial cells with the most abundant cell surface glycoconjugate of the parasite, the T. vaginalis lipophosphoglycan (LPG). Purified LPG mediated the adhesion of parasites to human vaginal epithelial cells in a dose-dependent manner. Furthermore, T. vaginalis LPG (but not LPG from Tritrichomonas foetus, the causative agent of bovine trichomoniasis) induced a selective upregulation of chemotactic cytokines by human endocervical, ectocervical, and vaginal epithelial cells, which do not express Toll-like receptor 4/MD2. The T. vaginalis LPG triggered interleukin 8 (IL-8), which promotes the adhesion and transmigration of neutrophils across the endothelium, and macrophage inflammatory protein 3alpha, which is a chemoattractant for immune cells and is essential for dendritic cell maturation. These effects were dose dependent and sustained in the absence of cytotoxicity and IL-1beta release and utilized, at least in part, a signaling pathway independent from the Toll-like/IL-1 receptor adaptor protein MyD88.

Mucosal innate immune factors in the female genital tract are associated with vaginal HIV-1 shedding independent of plasma viral load

Recent studies indicate that mucosal innate immune factors modulate HIV-1 infection in vitro. Our interest was to examine the levels of innate mucosal factors for their potential association with HIV-1 shedding in the female genital tract. Vaginal lavages were collected from HIV-1-infected women who had vaginal viral loads (VVL) that were below, within, or above the 90% confidence interval (CI) predicted by their matched plasma viral loads. Innate immune factors [cathepsin D, lactoferrin (Lf), myeloid related protein (MRP)-8, MRP-8/14, secretory leukocyte protease inhibitor, and gp340], cytokines (IL-1beta and TNF-alpha), and chemokines (MIP-1alpha, MIP-1beta, RANTES, and SDF-1alpha) were quantified by ELISA. Leukocyte levels were determined using a leukocyte reagent strip for urinalysis. Lf, MRP-8/14, gp340, and IL-1beta levels were significantly higher in vaginal lavages above the 90% CI and generally correlated with each other and with VVL. Leukocyte levels were significantly higher in the lavages that had virus shedding above the 90% CI and correlated strongly with Lf levels and VVL. In this group of women, these results suggest that the levels of certain innate immune factors are more closely associated with HIV-1 shedding in the genital mucosa than plasma virus concentrations.

Vaginal microbicides: detecting toxicities in vivo that paradoxically increase pathogen transmission

BACKGROUND

Microbicides must protect against STD pathogens without causing unacceptable toxic effects. Microbicides based on nonoxynol-9 (N9) and other detergents disrupt sperm, HSV and HIV membranes, and these agents are effective contraceptives. But paradoxically N9 fails to protect women against HIV and other STD pathogens, most likely because it causes toxic effects that increase susceptibility. The mouse HSV-2 vaginal transmission model reported here: (a) Directly tests for toxic effects that increase susceptibility to HSV-2, (b) Determines in vivo whether a microbicide can protect against HSV-2 transmission without causing toxicities that increase susceptibility, and (c) Identifies those toxic effects that best correlate with the increased HSV susceptibility.

METHODS

Susceptibility was evaluated in progestin-treated mice by delivering a low-dose viral inoculum (0.1 ID50) at various times after delivering the candidate microbicide to detect whether the candidate increased the fraction of mice infected. Ten agents were tested - five detergents: nonionic (N9), cationic (benzalkonium chloride, BZK), anionic (sodium dodecylsulfate, SDS), the pair of detergents in C31G (C14AO and C16B); one surface active agent (chlorhexidine); two non-detergents (BufferGel, and sulfonated polystyrene, SPS); and HEC placebo gel (hydroxyethylcellulose). Toxic effects were evaluated by histology, uptake of a 'dead cell' dye, colposcopy, enumeration of vaginal macrophages, and measurement of inflammatory cytokines.

RESULTS

A single dose of N9 protected against HSV-2 for a few minutes but then rapidly increased susceptibility, which reached maximum at 12 hours. When applied at the minimal concentration needed for brief partial protection, all five detergents caused a subsequent increase in susceptibility at 12 hours of approximately 20-30-fold. Surprisingly, colposcopy failed to detect visible signs of the N9 toxic effect that increased susceptibility at 12 hours. Toxic effects that occurred contemporaneously with increased susceptibility were rapid exfoliation and re-growth of epithelial cell layers, entry of macrophages into the vaginal lumen, and release of one or more inflammatory cytokines (Il-1beta, KC, MIP 1alpha, RANTES). The non-detergent microbicides and HEC placebo caused no significant increase in susceptibility or toxic effects.

CONCLUSION

This mouse HSV-2 model provides a sensitive method to detect microbicide-induced toxicities that increase susceptibility to infection. In this model, there was no concentration at which detergents provided protection without significantly increasing susceptibility.

Fourteen-day safety and acceptability study of 6% cellulose sulfate gel: a randomized double-blind Phase I safety study

BACKGROUND

Topical microbicides against the human immunodeficiency virus (HIV) 1 that are nonirritating to the female genital epithelium are urgently needed to slow the heterosexual spread of HIV infection. Products that are also effective contraceptives provide additional benefits. Cellulose sulfate (CS) is a noncytotoxic antifertility agent that exhibits in vitro antimicrobial activity against sexually transmitted pathogens, including HIV.

METHODS

We performed a multicenter, Phase I, placebo-controlled, randomized study to evaluate the genital toxicity of CS. Two cohorts of healthy women used 3.5 ml of 6% CS gel or 3.5 ml of K-Y Jelly, vaginally, bid, for 14 days. The first cohort was sexually abstinent, and the second cohort was sexually active.

RESULTS

CS was associated with only a slightly higher odds ratio (OR) of symptoms of minor urogenital irritation compared to the inactive lubricant K-Y Jelly (OR=2.02, 95% confidence interval=0.90-4.53). In addition, there were minor shifts in some genital flora, but there was no evidence of greater inflammation as evidenced by few colposcopic findings, decreased influx of polymorphonuclear cells and minimal changes in proinflammatory cytokines. Moreover, both products appeared acceptable to most women. Product leakage was identified as more of a problem in sexually abstinent women, but less so in women using the product for sexual intercourse, as would be the case in actual practice.

CONCLUSION

CS was safe for twice-daily use for 14 days. CS is appropriate for future studies in effectiveness trials.

In vitro determination of the contraceptive spermicidal activity of a composite extract of Achyranthes aspera and Stephania hernandifolia on human semen

OBJECTIVE

To evaluate the effect of a 50% ethanolic extract of the leaf of Stephania hernandifolia and the root of Achyranthes aspera on sperm motility and function in a ratio of 1:3 by weight at different concentrations.

RESULTS

Concentration of 0.08 g/mL of the extract affected the motility, and at a concentration of 0.16 g/mL, the sperm motility was reduced to 20% immediately (within 20 s). At a concentration of 0.32 g/mL, this composite extract showed the most promising results by complete sperm immobilization within 2 min after the application of the extract. The effects were spermicidal but not spermiostatic as sperm immobilization effect was found to be irreversible. Sperm viability was decreased significantly and was found to be nonviable after 30 min when treated with the composite extract at a concentration of 0.32 g/mL. The hypo-osmotic swelling of these sperm was reduced significantly at this highest concentration, indicating that the crude extract may probably cause injury to the sperm plasma membrane. A low concentration of 0.04 g/mL is ineffective.

CONCLUSION

The findings indicate that this composite plant extract possesses potential contraceptive spermicidal activity in vitro.

Prioritizing prevention of HIV and sexually transmitted infections: first-generation vaginal microbicides

PURPOSE OF REVIEW

As the HIV/AIDS pandemic continues unabated, novel control measures for the spread of HIV and other sexually transmitted infections are urgently needed. Topical microbicides are designed to prevent transmission of sexually transmitted infections when applied vaginally. The microbicides discussed in this review may provide a new opportunity for decreasing the spread of HIV and other sexually transmitted infections.

RECENT FINDINGS

Epidemiological studies suggest a synergistic relationship between HIV and sexually transmitted infections, particularly between HIV and genital herpes infection. Compounds have been developed to block transmission of HIV-1 and herpes simplex virus, as well as Neisseria gonorrhoea and Chlamydia trachomatis. Several of these compounds have advanced to clinical trials as candidate microbicides. Candidate compounds fall into the following categories: detergents or surfactants that inactivate viral particles, anionic polymers that block attachment of virus to target cells, vaginal acid-buffering agents that maintain a protective vaginal pH, and antiretroviral drugs specific for HIV. Evaluation of the safety of topical microbicides remains problematic. Clinical experiences indicate that current models to assess safety in vitro and in vivo may be insufficient to assess the safety of vaginal microbicides. A critical direction of future studies is to identify which assay(s) provide surrogate laboratory markers of safety that correlate with clinical outcomes.

SUMMARY

The spread of HIV, and its increasing burden of disease in women, necessitates the development of novel prophylactic strategies. Topical microbicides offer women an empowering preventative option but require vigorous testing for safety and effectiveness.

Polybiguanides, particularly polyethylene hexamethylene biguanide, have activity against human immunodeficiency virus type 1

Polyhexamethylene biguanide (PHMB) is a polybiguanide (PBG) oligomer with antimicrobial activity that is used extensively and safely as a disinfectant. The reported mechanism of PHMB antimicrobial activity, which involves interactions with cell membrane components, suggested that PHMB or other PBG-based compounds might also have antiviral or virucidal activity against the human immunodeficiency virus type 1 (HIV-1). PHMB had modest in vitro activity against both cell-free and cell-associated HIV-1, as well as the ability to interfere with viral binding and entry. However, PHMB was comparable in cytotoxicity to the spermicidal agent nonoxynol-9 (N-9), a compound that has been characterized in previous studies as generally cytotoxic and detrimental to cervicovaginal epithelial integrity. To identify structural variants of PHMB with greater anti-HIV-1 activity and/or less cytotoxicity, modified versions of PHMB incorporating length changes in the hydrocarbon linker units were synthesized and evaluated for in vitro cytotoxicity and inhibition of HIV-1 infectivity. These experiments demonstrated that the PHMB variant polyethylene hexamethylene biguanide (PEHMB) was just as active against HIV-1 as PHMB, yet was much less cytotoxic than either N-9 or PHMB, resulting in an in vitro therapeutic index (TI) approximately 114-fold greater than the TI of N-9. PEHMB, which has been identified in these studies as a promising microbicidal candidate in this family of compounds, will be the focus of further in vitro and in vivo evaluations of anti-HIV-1 activity, toxicity, and mechanisms of action.

Prolonged exposure to the candidate microbicide C31G differentially reduces cellular sensitivity to agent re-exposure

Comparative assays of in vitro cytotoxicity using nonoxynol-9 (N-9) and the candidate microbicides C31G and sodium dodecyl sulfate (SDS) demonstrated that these agents, which are, respectively, characterized as nonionic, amphoteric, and anionic surfactants, differed in their concentration-dependent effects on cell viability, especially after prolonged exposure. We hypothesized that differences in cellular sensitivity may have been due, in part, to cellular changes induced by long-term exposure to each agent. To examine this possibility, HeLa cells were exposed to N-9, C31G, or SDS for extended periods of time and subsequently reassessed for sensitivity to each of these agents. Following 10 continuous days of C31G exposure, HeLa cells were less sensitive to a subsequent C31G exposure compared to cells that had not undergone long-term C31G treatment. Interestingly, long-term C31G exposure also changed subsequent sensitivity to N-9 but not SDS. In contrast, prolonged exposure to either N-9 or SDS did not reduce sensitivity to re-exposure. The effect of long-term C31G exposure was both concentration-dependent and transient, as treated cells reverted to pre-exposure sensitivity in a time-dependent manner following the cessation of C31G exposure. Lipid analyses of cells exposed to C31G for extended durations revealed altered phospholipid profiles relative to C31G-naïve cells. Experiments examining the individual components of C31G demonstrated the involvement of the amine oxide moiety in reductions in cellular sensitivity. These studies, which provide new information concerning the cytotoxicity of surfactant microbicides, suggest that cervicovaginal epithelial cells may have greater in vivo tolerance for products containing C31G through unique interactions between C31G and components of the cellular membranes.

Toxicity, inflammation, and anti-human immunodeficiency virus type 1 activity following exposure to chemical moieties of C31G

C31G, which has potent activity against the human immunodeficiency virus type 1 (HIV-1) and an established record of safety in animal studies and human trials, is a microbicidal agent comprised of a buffered equimolar mixture of two amphoteric, surface-active agents: an alkyl amine oxide (C14AO) and an alkyl betaine (C16B). Studies of long-term in vitro exposure to C31G and its constituents have suggested that the components of C31G may contribute differentially to its toxicity and efficacy. In the present studies, in vitro assays of cytotoxicity and anti-HIV-1 activity demonstrated that C16B was slightly less cytotoxic compared to either C31G or C14AO, whereas the anti-HIV-1 activities of C31G and its individual constituents were similar. In the murine model of cervicovaginal microbicide toxicity, in vivo exposure to C14AO resulted in severe cervical inflammation followed by a delayed disruption of the columnar epithelium. In contrast, exposure to C16B caused severe cervical epithelial disruption and a secondary, less intense inflammatory response. These results demonstrate that (i) there are both mechanistic and temporal differences in toxicity associated with the components of C31G not necessarily predicted by in vitro assessments of cytotoxicity and (ii) contributions of each component to the anti-HIV-1 activity of C31G appear to be equal. In addition, these findings indicate that direct and indirect mechanisms of in vivo toxicity can be observed as separate but interrelated events. These results provide further insight into the activity of C31G, as well as mechanisms potentially associated with microbicide toxicity.