Rectal application of a highly osmolar personal lubricant in a macaque model induces acute cytotoxicity but does not increase risk of SHIV infection.

BACKGROUND: Personal lubricant use is common during anal intercourse. Some water-based products with high osmolality and low pH can damage genital and rectal tissues, and the polymer polyquaternium 15 (PQ15) can enhance HIV replication in vitro. This has raised concerns that lubricants with such properties may increase STD/HIV infection risk, although in vivo evidence is scarce. We use a macaque model to evaluate rectal cytotoxicity and SHIV infection risk after use of a highly osmolar (>8,000 mOsm/kg) water-based lubricant with pH of 4.4, and containing PQ15. METHODS: Cytotoxicity was documented by measuring inflammatory cytokines and epithelial tissue sloughing during six weeks of repeated, non-traumatic lubricant or control buffer applications to rectum and anus. We measured susceptibility to SHIVSF162P3 infection by comparing virus doses needed for rectal infection in twenty-one macaques treated with lubricant or control buffer 30 minutes prior to virus exposure. RESULTS: Lubricant increased pro-inflammatory cytokines and tissue sloughing while control buffer (phosphate buffered saline; PBS) did not. However, the estimated AID50 (50% animal infectious dose) was not different in lubricant- and control buffer-treated macaques (p = 0.4467; logistic regression models). CONCLUSIONS: Although the test lubricant caused acute cytotoxicity in rectal tissues, it did not increase susceptibility to infection in this macaque model. Thus neither the lubricant-induced type/extent of inflammation nor the presence of PQ15 affected infection risk. This study constitutes a first step in the in vivo evaluation of lubricants with regards to HIV transmission.

Physiologic doses of depot-medroxyprogesterone acetate do not increase acute plasma simian HIV viremia or mucosal virus shedding in pigtail macaques.

OBJECTIVE: Epidemiologic studies remain inconclusive on whether the injectable contraceptive depot-medroxyprogesterone acetate (DMPA) increases mucosal HIV shedding and transmissibility. Nonhuman primate models may help to determine the effects of DMPA on acute HIV replication. DESIGN: We defined a physiologic dose of DMPA in macaques and assessed the impact of DMPA on acute simian HIV (SHIV) replication. METHODS: Pigtail macaques received 1-30  mg of DMPA intramuscularly followed by measurements of progesterone and medroxyprogesterone acetate (MPA). Vaginal epithelial thickness, number of cell layers and density of intraepithelial CD3 cells were measured. The effect of DMPA on SHIV viremia and genital virus shedding was investigated in six pigtail macaques infected during monthly treatment cycles with 3  mg DMPA. Six DMPA-untreated macaques were controls. RESULTS: Plasma MPA concentrations directly correlated with changes in epithelial thickness (correlation = 0.84; P < 0.001) and density of intraepithelial CD3 cells (correlation = 0.41; P = 0.02). A 3 mg DMPA dose recapitulated plasma MPA concentrations and changes in vaginal epithelial thickness seen in women. DMPA-treated and untreated macaques showed similar peak plasma viremia and RNA area under the curve values over 12 weeks (P = 0.94), although treated macaques had higher odds of having virus being detected in plasma (odds ratio 6.6, P = 0.02). Rectal and vaginal virus shedding was similar between treated and untreated macaques (P  = 0.72 and P = 0.53, respectively). CONCLUSION: In this pigtail macaque model of DMPA and vaginal SHIV infection, we found little or no effect of DMPA on plasma viremia and mucosal virus shedding during acute infection. These results do not support a role of DMPA in increasing mucosal HIV shedding.