Status: 03.02.2023 4:46 p.m
As men age, some men lose the Y chromosome in part of their cells. Without this, they are more susceptible to certain diseases. But is that also why they age less?
By Nina Kunze, Elena Weidt, SWR
The life expectancy of men and women is noisy Federal Statistical Office has risen steadily in recent decades, but one difference remains: on average, men still die around five years earlier than women. A possible reason for this could be the Y chromosome.
Cells can lose Y chromosome
The so-called X and Y chromosomes belong to the genetic information in our body cells. Women usually have two X chromosomes in their cells, while men only have one – and an additional Y chromosome. This is significantly smaller than the X chromosome and ensures that male sexual characteristics develop in an embryo. However, the Y chromosome can be lost in men during cell division in the course of life.
This has been known in professional circles for a long time. This mutation is not entirely harmless, explains cardiologist Andreas Zeiher, who is researching the subject at Frankfurt University Hospital: “In the last two or three years there have been studies that have shown that if you lose this Y chromosome, you have it more often Cardiovascular diseases, also more frequently Alzheimer’s, diabetes and the classic age-related disease macular degeneration. So when your eyesight slowly fades. And building on that, you naturally thought: How can that be?”
Mainly affected blood cells
The loss of the Y chromosome occurs primarily in blood-forming cells, which produce billions of blood cells in the bone marrow every day, explains Zeiher. If such a blood stem cell loses its Y chromosome, all of its offspring will not have a Y chromosome either, and it will often even produce more new blood cells than others.
According to Zeiher, around 40 percent of men over the age of 70 are affected by this mutation, while the figure for 45-year-olds is only around five percent. However, not all blood stem cells lose the Y chromosome; a so-called mosaic of cells with different genetic information forms.
related to heart problems
A research team led by the cardiologist now wants to find out what changes in these cells as a result of the missing Y chromosome. Switching genes on or off could trigger pathological processes in the body.
To do this, the researchers regularly examine blood samples from elderly male patients with heart problems and look for cells with a missing Y chromosome. This shows that blood cells without a Y chromosome are significantly more common in men with heart disease than in healthy men.
changes in the organs
In animal experiments, one could research group in the United States already show the important role played by the Y chromosome in health. Blood cells without a Y chromosome triggered inflammatory processes in the animals – not only in the heart, but also in the lungs and kidneys.
The result: the tissue changes to scar tissue, a so-called fibrosis. Such scarring makes the heart stiffer and less able to pump, according to Zeiher. It has not yet been conclusively clarified whether the process can also be transferred to humans. But the cells of the patients at the Frankfurt University Hospital also produced more substances that trigger inflammation: “We therefore believe that the findings from mice can be transferred to humans.”
No therapy yet
There is still no therapy for the consequences of the missing Y chromosome. It is also not known whether the loss of the Y chromosome can be prevented. But there are certain lifestyle habits that encourage loss. Cardiologist Zeiher therefore recommends men to be physically active, not to smoke and to avoid stress.
The Frankfurt team hopes to uncover further consequences of the missing Y chromosome in the body and to be able to develop therapies against the associated medical problems.