Friday, March 13, 2009

Protecting women from HIV...

One of your classmates brought this to my attention (thanks Kristin)... pretty interesting stuff. Recent research has been investigating creams and gels that can potentially reduce HIV transmission to women. As we discussed in class, HIV tends to infect immune cells such as macrophages (dendritic cells too?) and Helper T cells (CD4+ lymphocytes). The transmission often takes place in the vaginal mucosa and epithelium. Gels or creams containing chemicals that destroy the virus (microbicides) or prevent the viral infection of the immune cells would reduce transmission, and hopefully decrease or prevent the spread of HIV.

A recent study published in the journal Nature showed reduced virus transmission in a primate model of HIV using the chemical glycerol monolaurate (an ingredient reportedly used in ice cream, cosmetics and found in breast milk). Researchers tested glycerol monolaurate, spiked into K-Y jelly, in their study using macaque monkeys. They put the gel into the vagina of the monkeys and then applied SIV, a monkey version of HIV. Monkeys treated with the chemical appeared to be protected from vaginal HIV exposure while untreated monekys became infected with HIV. Here is a link to a Reuters article reporting the research (link) and here is a link to the PubMed citation for the actual study (link).

Another interesting fact discussed in the article is related to initial HIV infection and transmission. It is reported that HIV infects or activates resident immune cells in the vaginal mucosa like macrophages and dendritic cells. These cells induce inflammation (via cytokines) and most importantly they cause the recruitment of helper T cells (CD4+) to the site of viral infection, in this case the vagina. It seems that this initial recruiting of CD4+ cells to the local site of infection is an important step the systemic spread of HIV which further infects CD4+ lymphocytes throughout the body.

Interestingly, I recall a study not too long ago investigating a microbicide cream used in the vagina that was designed to reduce or prevent HIV transmission. The study was halted because the researchers found the gel actually increased HIV infection... apparently the gel caused inflammation and irritation of the vagina which would then increase the risk of HIV infection in the female. Obviously these strategies have some potential but research and product development have a long way to go.

~~ BIO26 ~~