Equality of the sexes? Not always when it comes to biology
MUHC researchers demonstrate that estrogen renders the innate immune system of women more powerful than that of men.
When it comes to immunity, men may not have been dealt an equal
hand. The latest study by , of the Research Institute of the ÎÛÎÛ²ÝÝ®ÊÓƵ University
Health Centre and ÎÛÎÛ²ÝÝ®ÊÓƵ University, shows that women have a more
powerful immune system than men. In fact, the production of
estrogen by females could have a beneficial effect on the innate
inflammatory response against bacterial pathogens. These surprising
results will be published today in the Proceedings of the National
Academy of Sciences.
More specifically, estrogen naturally produced in women seems to
block the production of an enzyme called Caspase-12, which itself
blocks the inflammatory process. The presence of estrogen would
therefore have a beneficial effect on innate immunity, which
represents the body's first line of defence against pathogenic
organisms. "These results demonstrate that women have a more
powerful inflammatory response than men," said Dr. Saleh.
This study was conducted on mice that lack the Caspase-12 gene,
meaning that the mice were extremely resistant to infection. The
human Caspase-12 gene was implanted in a group of male and female
mice, yet only the males became more prone to infection. "We were
very surprised by these results, and we determined that the
estrogen produced by the female mice blocked the expression of the
human Caspase-12 gene," explained Dr. Saleh. "We were also able to
locate where the estrogen receptor binds on the gene in order to
block its expression, which indicates that the hormone exerts
direct action in this case."
Since these experiments were conducted using a human gene, the
researchers consider these results to be applicable to humans. This
feature of the female innate immune system might have evolved to
better protect women's reproductive role.
The positive effect of natural estrogen on our resistence to
infection is also exhibited with synthetic hormones such as
17-beta-estradiol. This finding might therefore open the door to
new therapeutic applications that reinforce the immune system, but
a question remains: will men be amenable to the idea of being
treated with an exclusively female hormone?
Funding
This study was supported by grants from the Canadian Institutes for
Health research and the Canadian Foundation for Innovation.
Dr. Maya Saleh is a researcher with the Critical Care Division and
the Centre for the Study of Host Resistance at the Research
Institute of the ÎÛÎÛ²ÝÝ®ÊÓƵ University Health Centre (MUHC) as well as
an assistant professor with ÎÛÎÛ²ÝÝ®ÊÓƵ University's Faculty of
Medicine.
Partners
This project is a collaboration between the laboratory of Dr Maya
Saleh at the Centre for the Study of Host Resistance at the
Research Institute of the MUHC, Montreal, with Garabet Yeretssian,
Karine Doiron and Wei Shao, the laboratories of Dr Blair R. Leavitt
and Michael R. Hayden both at the Centre of Molecular Medicine and
Therapeutics, Vancouver, and the laboratory of Dr Donald W.
Nicholson at Merck Research Laboratories, USA.
You will find this press release, with the original article and a
short audio interview by following this link:
The Research Institute of the ÎÛÎÛ²ÝÝ®ÊÓƵ University Health
Centre (RI MUHC) is a world-renowned biomedical and
health-care hospital research centre. Located in Montreal, Quebec,
the institute is the research arm of the MUHC, the university
health center affiliated with the Faculty of Medicine at ÎÛÎÛ²ÝÝ®ÊÓƵ
University. The institute supports over 600 researchers, nearly
1200 graduate and post-doctoral students and operates more than 300
laboratories devoted to a broad spectrum of fundamental and
clinical research. The Research Institute operates at the forefront
of knowledge, innovation and technology and is inextricably linked
to the clinical programs of the MUHC, ensuring that patients
benefit directly from the latest research-based knowledge.
The Research Institute of the MUHC is supported in part by the
Fonds de la recherche en santé du Québec.
For further details visit: .mark.shainblum [at] mcgill.ca