Two times more adult women than adult men suffer from allergic asthma in France
Why this difference? Impossible to answer this question. Scientists suspected the female hormones to maintain a link with the triggering of asthma.
They might need to think a little differently.
According to four studies conducted by different teams of researchers, it is the testosterone that could have a protective role.
“It is admitted that young boys are more likely to be asthmatic. However, at the time of pre-adolescence, around 10 – 12 years, a reversal takes place.
Women are two times more likely than men to be asthmatic,” says professor Anne Prudhomme, coordinator of the group “Women and respiratory disease” from the French society of pneumology and respiratory physician at CHU de Bigorre, Tarbes. Production of mucusDans to a study published November 28 in the journal Cell Reports, the researchers have conducted a blood sample taken in 17 men and women, with or without asthma.
People with severe asthma or moderate were more white blood cells individuals (lymphoid cells innate type 2 or type ILC2) than healthy individuals (men and women). In addition, women with asthma had themselves two times more of ILC2 than men. The ILC2, from the bone marrow, produce substances that cause inflammation (cytokine) and the production of mucus in the bronchi. This leads to a greater production of white blood cells, and maintains the circle of the inflammation of the bronchial tubes. From these observations, the researchers used mice to see the effect of the change of hormones in the inflammation of the bronchial tubes.
They have tested several situations, either in castrant, either in supplémentant mice by hormones. Scientists have observed that testosterone prevented the ILC2 to produce the substances responsible for the inflammation. De new cells”When we started this study, we thought, really, that the female hormones would aggravate the inflammation. And not that the testosterone could have a protective role. We were very surprised by this result”, says Dawn Newcomb, a researcher at the medical center of Vanderbilt University (Usa) and lead author of the study of Cells Reports (29 November). “The cells ILC2, have been discovered there are just a few years ago,” explains Jean-Charles Guéry, author of a similar study on mice, presented in march in The Journal of Experimental Medcine.
The discovery of these cells has led to new hypotheses regarding the inflammatory disease of the asthma. “Mimic the beneficial action”ultimately, the goal of this research would be to find molecules “that mimic the beneficial action without having detrimental effects for women of testosterone on the tissues of sexual. If one understands the mechanism of the action of the hormone on the tissues of the bronchi, there will be new therapeutic targets,” explains Jean-Charles Guéry. Currently asthma is treated with beta mimetics (in the case of a crisis less harsh) or corticosteroids, inhaled (reserved for larger crises). According to the public Health agency of France in a report in 2010, “in the adult the proportion of women with asthma increases with age, from 43.5% in the 15 to 44 years of age” to “54,5% among those 65 to 74 years”.