Pigtailed macaque model refinement: topical microbicide safety in the presence of coitus.

BACKGROUND: Inclusion of sexual activity in the macaque model for topical microbicide safety evaluation would more closely mimic human use of topical microbicides and provide a more rigorous safety assessment. METHODS: Initially, male-female partners were monitored in cohousing arrangements to determine whether macaques would copulate ad libitum. The logistics of performing vaginal examinations before and after coital visits were analyzed and optimized. Findings from cervicovaginal examinations conducted before and after sexual activity were compared. RESULTS: Coital activity was reliably observed in the majority of cohousing sessions, representing all phases of the menstrual cycle. Female macaques were trained to be restrained while fully alert for pre-coital vaginal sampling. Post-coital examinations occur under general sedation. Post-coital examinations reveal alterations to tissues, microbiology, and pH compared with pre-coital visits. CONCLUSIONS: This work clearly demonstrates that it is feasible to incorporate sexual activity in the macaque model for topical microbicide safety assessment.

A summary of preclinical topical microbicide rectal safety and efficacy evaluations in a pigtailed macaque model.

BACKGROUND: There is widespread recognition of the potential promise of vaginal microbicides as a tool to combat global human immunodeficiency virus/acquired immunodeficiency syndrome and sexually transmitted infections epidemics, and candidate product development has maintained a rapid pace in recent years; however, rectal microbicide development has received less attention. As it is likely that commercial products developed for vaginal use will also be used rectally, there is a clear need to assess the safety and efficacy of candidate microbicide products specifically in the rectal compartment. METHODS: We have developed a standardized protocol for preclinical rectal safety and (chlamydial) efficacy assessment of topical microbicide candidates in a nonhuman primate model. We evaluated a total of 12 test compounds for rectal safety (via rectal pH, microflora, and rectal lavage) and 1 compound for efficacy against rectal chlamydial infection. RESULTS: In this article, we describe our methods in detail and summarize our results, particularly noting the ability of our model to distinguish products with deleterious effects on the rectal environment. We also outline the specific criteria used to recommend products move into preclinical rectal efficacy trials or be recommended for reformulation to the product developer. In summary, we observed significant adverse effects in 2 products. The single product that underwent efficacy evaluation was not observed to be protective against rectal chlamydial infection. CONCLUSIONS: A preclinical safety and efficacy model is critical to promoting rectal microbicide development, which will ultimately offer a significant opportunity for intervention in the global HIV/AIDS epidemic.

Application of optical coherence tomography for monitoring changes in cervicovaginal epithelial morphology in macaques: potential for assessment of microbicide safety.

OBJECTIVES: Safety is a primary concern in the development of topical microbicides. Optical coherence tomography (OCT), a high-resolution, in-depth cross-sectional imaging modality, was utilized in conjunction with colposcopy to assess induced cervicovaginal epithelial changes that may predict product safety. STUDY DESIGN: OCT and colposcopic images of macaque vaginal and cervical tissues were obtained in excised tissue and in vivo under various conditions, including mechanical injury and nonoxynol-9 treatment. RESULTS: A scoring system was developed to categorize and quantify the OCT images based on morphologic features that indicate the presence or absence of an intact epithelial layer and inflammation. Using 3 categories (normal, mild to moderately abnormal, and severely abnormal), differences between healthy and injured tissue were apparent on OCT images. Normal images (category 1) had a bilayered structure representative of the epithelium and submucosa. Mild to moderately abnormal images (category 2) had areas of normal and abnormal epithelium. Severely abnormal images (category 3) had complete loss of the epithelium and/or inflammation, with loss of the bilayered structure on OCT. CONCLUSIONS: OCT is a noninvasive imaging modality complementary to colposcopy. It distinguished between normal and abnormal (or injured) tissue and thus holds promise for safety evaluations of candidate microbicides and other vaginal products.

Vaginal and rectal topical microbicide development: safety and efficacy of 1.0% Savvy (C31G) in the pigtailed macaque.

BACKGROUND: A 1.0% gel formulation of C31G, a surfactant, has been shown to have in vitro antiviral and antibacterial activity. GOAL: The goal of this study was to evaluate the safety and efficacy of vaginal and rectal applications of 1.0% Savvy (C31G) in the nonhuman primate model. STUDY DESIGN: The safety of repeated 1.0% C31G application was evaluated by microflora, pH, vaginal biopsy, colposcopy, and rectal lavage. Efficacy in preventing chlamydial infection was documented by culture, nucleic acid amplification tests, and serology. RESULTS: Repeated applications of Savvy (1.0% C31G) were not associated with significant changes in pH, microflora, or inflammatory infiltrates on tissues. No significant differences in epithelial desquamation were noted after rectal product use compared with placebo. Four of 6 animals were protected from chlamydial infection after pretreatment with Savvy. C31G was shown to be safe to both vaginal and rectal mucosal tissues and to the microflora with repeated daily use. CONCLUSION: Savvy has an acceptable safety profile after repeated vaginal and rectal use. A single intravaginal application of 1.0% C31G provided partial protection from acquiring cervical chlamydial infection.

Development of a nonhuman primate model for Trichomonas vaginalis infection.

OBJECTIVE: Trichomoniasis, caused by Trichomonas vaginalis, is a prevalent sexually transmitted infection associated with increased risk of HIV infection. An animal model of T. vaginalis infection would enable scientists to further investigate trichomoniasis. STUDY DESIGN: Seven macaques (4 test vs. 3 control) were enrolled in a 2-week pilot study. Eight additional animals participated in a 2-arm (T. vaginalis vs. sham inoculated) crossover study lasting 5 weeks before treatment. In all, 12 Macaca nemestrina monkeys were challenged with a single intravaginal inoculation of 6.6 to 7.1 x 10(5) trichomonads (ATCC 50148). Vaginal culture (InPouch TV), colposcopy, microbiology, pH, and cervical cytokines were assessed at baseline, day 2, and weekly thereafter. RESULTS: Ten of 12 challenged animals tested positive for trichomoniasis for 2 weeks or longer. One animal tested positive on days 2 and 7 but negative thereafter. Only one animal was not infected. Oral metronidazole treatment (35 mg/kg per day for 3 days) resolved infection in all animals. Trichomoniasis infection did not lead to shifts in vaginal microbiology or pH. CONCLUSIONS: A single T. vaginalis inoculation results in persistent infection in the pigtailed macaque.

Significant reduction in inflammatory response in the macaque model of chlamydial pelvic inflammatory disease with azithromycin treatment.

We inoculated 45 female macaques in the cervix with Chlamydia trachomatis once weekly for 5 weeks and randomly assigned them to treatment with doxycycline (n=12), azithromycin (n=12), or placebo (n=21). At hysterectomy, cervical cultures remained positive in 12 of 21 placebo-treated monkeys, versus 0 of 12 doxycycline- or azithromycin-treated monkeys (P<.01); cervical ligase chain reaction remained positive in 15 placebo-, 1 doxycycline-, and 0 azithromycin-treated monkeys. Tubal swabs remained positive in 3 placebo-, 1 doxycycline-, and 0 azithromycin-treated monkeys. Immunopathologic damage was moderate to widespread in upper and lower reproductive-tract tissues from placebo- and doxycycline-treated monkeys but were significantly reduced in azithromycin-treated monkeys. Transforming growth factor- beta was also significantly less prevalent in azithromycin-treated monkeys. Azithromycin treatment dramatically reduced the inflammatory response and was highly effective in eradicating C. trachomatis from the lower and upper reproductive tract (12/12), compared with doxycycline (7/12) and placebo (3/21).

Heat shock protein 60 is the major antigen which stimulates delayed-type hypersensitivity reaction in the macaque model of Chlamydia trachomatis salpingitis.

Chlamydial delayed-type hypersensitivity antigens were analyzed by using the subcutaneous salpingeal autotransplant model of Macaca nemestrina infected with Chlamydia trachomatis serovar E. Heat shock protein 60 was the only antigen shown to induce delayed-type hypersensitivity among other antigens tested, including UV-inactivated organisms, recombinant major outer membrane protein, purified outer membrane proteins, and heat shock protein 10.