(http://www.sciencedaily.com/releases/2012/05/120524092750.htm)
Cystic Fibrosis Breakthrough Reveals
Why Females Fare Worse Than Males
ScienceDaily (May 24, 2012) — Researchers from the Respiratory Research Division of the
Department of Medicine, Royal College of Surgeons in Ireland (RCSI) have published a study
which represents a major breakthrough in understanding why females with cystic fibrosis do
worse than males. The study is the first to show that the female hormone estrogen promotes
the presence of a particular form of bacteria which results in more severe symptoms for
female cystic fibrosis patients. In addition, females who were taking the oral contraceptive pill,
which decreases the amount of naturally occurring estrogen in their bodies, were found to
have lower levels of the problematic bacteria.
The paper was published May 24 in the New England Journal of Medicine.
The research found that estrogen promoted the presence of a 'mucoid' form of the bacterium
Pseudomonas aeruginosa in the lungs of women with cystic fibrosis. These mucoid type of
Pseudomonas aeruginosa bacteria are coated in a slimy layer which makes them more
difficult to treat with antibiotics and more difficult to clear with the body's own natural defenses
which leads to significant lung inflammation, explaining, at least in part, why females with
cystic fibrosis often have a worse outcome.
Professor Gerry McElvaney, Director of the Respiratory Research Laboratory
RCSI/Beaumont Hospital and joint senior author on the paper commented: "This study opens
the way to a new understanding and potentially new therapies in the treatment of cystic
fibrosis, a condition in which Ireland has the highest incidence in the world. This research
study is among the first examples which shows the effects of gender hormones on infections
and therefore has major implications for conditions beyond cystic fibrosis including other
respiratory diseases such as asthma."
Dr. Sanjay Chotirmall, a Molecular Medicine Ireland (MMI) Clinician-Scientist fellow is the first
author on the paper and Dr. Catherine Greene is the joint senior author.
The clinical research was carried out in the Cystic Fibrosis Unit, Beaumont Hospital and also
utilised data from the National Cystic Fibrosis Registry of Ireland.
Cystic fibrosis is a life threatening inherited disease which primarily affects the lungs and the
digestive system. A build up of mucus can make it difficult to clear bacteria and leads to
cycles of lung infections and inflammation, which can eventually lead to damage of the lungs.
Ireland has both the highest incidence of CF in the world at 2.98 per 10,000 and the highest
carrier rate in the world with 1 in 19 individuals classed as carriers. The incidence of cystic
fibrosis in this country is almost two and a half times the average rate in other EU countries
and the USA (1). At present, there are approximately 1,200 people with cystic fibrosis living in
Ireland (2).
The cystic fibrosis research in the Respiratory Research Division exemplified by this paper is
funded by the Health Research Board, Medical Charities Research group, Science
Foundation Ireland, Molecular Medicine Ireland (MMI), CF Hopesource, Irish CF research
trust along with individual donors such as Fergal Somerville who recently swam the English
Channel in support of CF research in Beaumont Hospital.
This paper is an excellent example of the translational research presently underway in RCSI
and illustrates interdepartmental and inter-institutional links as co-authors on the paper
include colleagues from the Departments of Medicine (Dr. Sonya Cosgrove), General Practice
(Dr. Borislav Dimitrov) and Molecular Medicine (Professor Brian Harvey), RCSI; Beaumont
Hospital/RCSI (Dr. Cedric Gunaratnam, Professor Shane O'Neill); and the School of Medicine
(Dr. Stephen Smith), Trinity College, Dublin.
The study's results are being presented by Dr. Greene at the American Thoracic Society
meeting in San Francisco this month and by Dr. Chotirmall at the European Respiratory
Society meeting in Vienna later this year
(1) Farrell PM. The prevalence of cystic fibrosis in the European Union. Journal of Cystic
Fibrosis 2008 Sep;7(5):450-3.
(2) The Cystic Fibrosis Registry of Ireland