One study published last Thursday (14) in the scientific journal Science may help explain why, in general, men die before women –in Brazil, life expectancy for them would be 73.3 years and for them, 80.3 yearsaccording to the IBGE, disregarding the mortality caused by covid-19 pandemic.
According to the research, conducted by 25 scientists from the United States, Sweden and Japan, the lack of the Y chromosome observed in a part of the cells as men age – it is estimated that it affects 40% of the elderly in their 70s – favors the appearance of myocardial fibrosis, with involvement of heart muscle cells, and heart failure.
“Although loss of the Y chromosome has already been associated with a shorter life span and increased risk of age-related diseases, a major unaddressed question was whether this loss would play a causal role in the pathological process,” says researcher Kenneth Walsh. , a professor at the Virginia Unity School of Medicine and one of the authors of the article.
“Some even argued that the loss of the chromosome would be a benign indicator of aging, such as gray hair or wrinkles. Therefore, we carried out a study to investigate whether it has a direct role in the disease process and to elucidate how it contributes to diseases”, he says.
The study reveals that male mice treated to lose their Y chromosome in blood cells, which occurs in elderly men, had excessive deposition of connective tissue in the heart, kidneys and lungs. In other words, a set of immune system responses led to a process known as fibrosis, affecting the functioning of different parts of these animals’ bodies. The research also points out that rodents without Y had a shorter life span.
The researchers also conducted analyzes from the UK Biobank, a repository containing medical data from around half a million people, and found an association between a lack of the Y chromosome, cardiovascular disease and heart failure.
Following these findings, the team focused on the heart as it understood that it could help elucidate a mechanism that contributes to non-ischemic heart failure, a condition that affects about 3 million people in the United States alone. “This form is poorly understood in relation to classic ischemic heart failure, which results from the blockage of a main artery that supplies blood to the heart muscle. Furthermore, there are very few treatment options for it,” explains Walsh.
According to the researchers, a neutralizing antibody used in a portion of the mice attenuated part of the damage to the heart and may be able to reverse part of the cardiac impacts triggered by the lack of the Y. This is one of the next steps of the research. Another is to seek to understand who, in addition to smokers, is more susceptible to the negative effects of loss and why.
“Now that there is an experimental model for analysis in mice, we can study why the Y chromosome is lost and how to preserve it”, says the professor.
“Above all, we need to define the genes on the Y chromosome whose loss leads to these disease conditions,” he continues. “Once these genes have been identified, we will be able to carry out more in-depth studies that may reveal new features of the disease and aging process, and lead to the development of new therapies.”
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