This phenomenon which affects 40 % of 70 -year -old men would notably promote fibrosis of heart muscle. An international team describes the mechanism in question.
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is this little chromosome which, coupled with the X chromosome, gives an individual male sex, while women present the chromosomal XX pair. The Y could also be responsible, by its fragility, for the greatest mortality of cardiac origin observed in men. A study published on July 15 in the journal Science shows, for the first time, a causal link between the loss of chromosome y in certain blood cells, observed during aging, and a phenomenon of cardiac fibrosis.
“This is a very good study, methodologically very complete, and I do not say it because I had the opportunity to co -wire work with one of its main authors, Lars Forsberg”, greets Jean -Charles Lambert, of the Institut Pasteur Lille, which is also interested in this phenomenon of loss in mosaic of chromosome y (known as “mloy”, for mosaïc loss of chromosome y), but in connection with Alzheimer’s disease .
Lars Forsberg (University of Uppsala, Sweden) was one of the pioneers on the subject, showing through epidemiology that the partial loss of the Y chromosome, which increases with age and smoking – it is detectable in 40 % of men aged 70 and 57 % of those aged 93 -was associated with an increase in the risk of cancer, cardiovascular disease and Alzheimer, and a drop in life expectancy. “But the question remained whether it was really causal, or simply an aging sign, a question to which epidemiology could not answer,” notes Jean-Charles Lambert.
a cascade of reactions
This is the reason why Lars Forsberg and an international team of researchers have developed a model of mouse whose hematopoietic cells, at the origin of the various blood cell lines (red and white blood cells in particular), were devoid of chromosome Y. These rodents had a shortened life expectancy, and signs of cardiomyopathy and heart failure in the oldest. Fibrosis were observed not only in heart muscle, but also in lungs and kidneys.
The researchers then returned to epidemiology, by drawing data from the UK Biobank on a large sample of men, whose percentage of Mloy among blood cells was known. It turns out that those presenting at the start of the observation period a Mloy for more than 40 % of leukocytes – the famous white blood cells in the immune system – had a 31 % increased risk of being dead from a circulatory system disease Ten years later, and an increased risk of 41 % for any cause of mortality.
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