Research Profile – Hormones, microbiome and innate immunity

Photo: Dr. Charu Kaushic

Interactions between sex hormones, microbiome and innate immunity in the female reproductive tract: impact on mucosal immune responses and susceptibility to HIV

Women are at a higher biological risk for HIV infection compared to men and the vast majority of women get infected by HIV through sexual transmission. Female sex hormones and hormonal contraceptives have been shown to affect the ability of HIV to infect the female reproductive tract. Although the exact way in which these hormones influence HIV infection is unknown, we do know that sex hormones control the ability of the immune system to fight HIV infection in the reproductive tract. We also know that a combination of sex hormones and good bacteria control vaginal colonization. When the balance of healthy vaginal microflora is disrupted, it leads to inflammation in the reproductive tract which in turn increases risk of HIV infection.

The studies will be carried out by a team of scientists and clinicians in consultation with community members at research labs in McMaster University and University of Manitoba in collaborations with clinics in Kenya and Women’s Health in Women’s Hand in Toronto. Through a combination of clinical studies and animal experiments, this team will see if progesterone-based hormonal contraceptives lead to a “less healthy” vaginal microflora and more inflammation in the genital tract which could increase HIV risk. The second approach will be to directly deliver probiotics or small amounts of estrogen in clinical studies and in animal models to determine if this makes the vaginal microflora healthy and decreases local inflammation thereby decreasing HIV risk.

The studies proposed in this team grant provide an innovative approach that could decrease susceptibility and inflammation by altering local hormonal environment and/or re-balancing the vaginal microflora by probiotics.

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