WESTPORT, CT (Reuters Health) – Nonoxynol-9, a common component of vaginal spermicides and lubricant products, can increase the risk of HIV-1 transmission by causing inflammation of cervicovaginal epithelial cells, according to US researchers.
More than year ago, researchers first reported that nonoxynol-9, then under investigation as an HIV-1 microbicide, actually promoted transmission of the virus. (see Reuters Health report, June 13, 2000). A warning against the use of nonoxynol 9 as a means of HIV-1 prevention was subsequently issued by the US Centers for Disease Control and Prevention (see Reuters Health report August 15, 2000).
Now, in a paper published in the August 15th issue of The Journal of Infectious Diseases, Dr. Deborah J. Anderson of Brigham and Women's Hospital in Boston and colleagues describe the mechanisms underlying this unexpected effect.
The investigators examined the effects of nonoxynol-9 on vaginal and cervical epithelial cells in vivo and in vitro in 10 healthy women and in 3 cell lines. Cervicovaginal lavage samples were collected before and after treatment with one or three doses of nonoxynol-9.
While one-time use of the microbicide had no apparent effect on cervicovaginal cells up to 60 hours after use, the protocol of three daily applications resulted in the generation of a "striking" inflammatory response, Dr. Anderson told Reuters Health.
Specifically, in vivo and in vitro, the authors observed activation of epithelial cells and U1/HIV promonocytic cells leading to increased chemokine production (interleukin-1 and NF-gamma-B) and recruitment of HIV-1 host cells. Moreover, in in vitro models, the authors noted "increased HIV-1 replication in infected cells."
The findings indicate that the regular use of nonoxynol-9 "should be rethought" in HIV-endemic areas and among women at increased risk of HIV infection, Dr. Anderson told Reuters Health. The study findings also suggest that the production of pro- and anti-inflammatory molecules should be monitored in future studies of candidate vaginal microbicides.