Research conducted jointly at the University of Virginia (UVA) U.S., and Uppsala University in Sweden has shown that the loss of Y-chromosomes in the white blood cells of men as they age can lead to increased risk of heart failure and other cardiac diseases. The findings may help to know why millennial males die early than millennial women.
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What are Y-chromosomes?
Humans have 23 pairs of chromosomes in one cell. One of these pairs is sex chromosomes, called the X and Y chromosomes. Males have one of each, while women have two X-chromosomes. The Y-chromosome is very small in size and represents 2 percent of the cell’s total DNA. Because it is present only in males, the genes of this chromosome are involved in the sex determination of the human child or other mammals.
Can Y-chromosomes disappear?
Scientists have known that some men start to lose Y-chromosomes from their cells when they get older. A previous UK study on thousands of males revealed that the Y-chromosomes were absent in about a fifth of those aged between 40 to 70 years old. The loss of this chromosome occurs predominantly in cells that undergo rapid changes, such as blood cells. Besides humans, some mammals also lack Y-chromosomes. These are Transcaucasian mole voles, creeping voles and three rare species of spiny rat from Japan.
How does a lack of Y-chromosomes potentially affect male health?
Researchers discovered that the Y-loss phenomenon had been linked to severe health conditions, including cardiovascular diseases, cancer, Alzheimer’s disease and a shorter lifespan. They proved their results by studying the mice.
They found that mice lacking Y-chromosomes from their white blood cells died earlier than the mice that still had Y-chromosomes. These mice with low Y-chromosomes also developed fibrosis (thickening of the tissue) that stiffens the heart and makes it harder for it to pump the blood.
The researchers then checked the genetic and medical information of more than 223,000 men who gave blood samples to the UK Biobank. They discovered that men who had lost Y-chromosomes from more than 40 percent of their white blood cells were 31 percent more likely to die from heart diseases.
The researchers concluded that these results suggested that the loss of Y-chromosomes results in cardiac dysfunction, fibrosis of the heart muscle and mortality in men. They thought that the Y-loss affects how some cells in the heart work, causing cardiac disease and fibrosis.
“As we age, one of the things that happen is that we develop fibrosis in various tissues and organs, including the heart, kidneys and lungs. And that process is accelerated by the loss of the Y-chromosome,” said Kenneth Walsh, a Researcher in the Internal Medicine Department at UVA.
Although there is no treatment for fibrosis yet, researchers are working on new medications to reverse the damage.
The detailed research has been published in the journal Science.
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