Scientists in Canada have developed a vaginal implant that can protect women from becoming infected with HIV.
The researchers stated how they successfully tested the vaginal implant in laboratory animals.
HIV, the virus that causes AIDS, captures activated immune T cells to use their machinery to complete its life cycle. A major site of spread is in the female genital tract.
The new vaginal implant slowly releases drugs that keep the T cells of the female genital tract in a resting or inactive state, which is much less productive for the virus.
Quiescent T cells can block the initial stage of the HIV life cycle, resulting in a largely useless spread.
What Instigated the Discovery?
Professor in the School of Pharmacy at the University of Waterloo in Canada, senior study author Emmanuel Ho and colleagues came up with the idea of a vaginal anti-HIV implant after studying the commercial sex workers in Kenya, East Africa.
They observed that many female sex workers did not become HIV-positive, even though they were having unprotected sex with clients who were.
Further analysis revealed that the women’s natural resistance to HIV came from the fact that their immune T cells remained in a quiescent state.
Upon this discovery, the researchers wondered whether it might be possible to induce T cell quiescence in the female genital tract with drugs.
This approach could provide an excellent women-oriented approach against HIV transmission.
Prof. Ho says that they decided to pursue the idea of a vaginal implant rather than an oral drug because some drugs taken orally never make it to the vaginal tract.
A vaginal implant that can block HIV could offer a cheaper, more reliable way of preventing transmission, Prof. Ho stated.
There are 36.7 million people living with HIV or AIDS globally, including 2.1 million children under the age of 15.
Most of the 160,000 children newly diagnosed with HIV yearly live in sub-Saharan Africa. Their mothers spread the virus either during pregnancy, while giving birth, or when breast-feeding.
The implant is a permeable, hollow tube filled with a drug that is secreted slowly and is absorbed into the walls of the female genital tract. The tube has two flexible arms that prevent it from moving around.
The research team filled the vaginal implant with hydroxychloroquine and tested it in rabbits. The implant caused a significant reduction in activated T cells, indicating that it induced “an immune quiescent state” in the genital tracts of female rabbits.
The scientists noted that it is not yet certain if this can be a stand-alone option for preventing HIV transmission or if it might be best used in combination with other prevention approaches.
The report was published in the Journal of Controlled Release.