In a world first, a University of Melbourne study has shown that topical oestrogen could help prevent HIV infection by blocking entry of the virus into the human penis.

The study to be published in PLoS ONE journal June 4 reveals that application of oestrogen to the human penis increased the thickness of the natural keratin layer on the skin, which could prevent HIV from infecting the male.

The epithelium of the human penis is richly supplied with oestrogen receptors suggesting it could respond to topical oestrogen.

Dr Andrew Pask from the Department of Zoology at the University of Melbourne analysed the tissue samples from 12 foreskins and made the discovery.

“This suggested that oestrogen could induce a thickening of the keratin layer of the foreskin epidermis in the same way as it acts in the vagina,” said Dr Pask.

“Keratin on our skin acts a barrier to viral infection. We hope to be able to enhance this protection with the use of a naturally occurring, weak oestrogen,” said Professor Roger Short of the Faculty of Medicine, Dentistry and Health Sciences who lead the research.

To confirm its effect, topical oestrogen was applied to the human foreskin for a two week trial. This resulted in a rapid and substantial increase in keratin thickness.

“We have found a new avenue to possibly prevent HIV infection of the penis.”

HIV is one of the greatest health crises the world has ever seen, and affects over 40 million people worldwide.

Professor Short says that HIV is on the rise particularly in countries where males are not circumcised.

“In countries where circumcision is not religiously or culturally accepted, oestrogen treatments to the penis could be very effective in reducing the spread of the disease.”