A new study published on Thursday found that the loss of Y chromosomes in white blood cells – a genetic change found predominant in elderly men – is associated with an increased risk of cardiovascular disease and organ damage, and could be one of the reasons men tend to die earlier than women on average.
How was the Y chromosome study conducted?
The study, which was published in the peer-reviewed scientific journal Science, discovered that roughly 20% of 60-year-olds and 40% of 70-year-old men who suffer from loss of Y chromosomes may suffer from heart failure and other organ damage – whereas it was previously thought that loss of Y chromosomes increased risk of developing age-related diseases such as cancer and Alzheimer's disease.
Researchers used the gene-editing tool CRISPR to generate mLOY (mosaic loss of Y chromosomes) in the white blood cells of mice, finding that mLOY caused direct damage to the animals' internal organs and that mice with mLOY had shorter lives than mice without mLOY.
“In the mouse models used in the study, the mouse Y chromosome was eliminated to mimic the human mLOY condition and we analyzed the direct consequences that this had,” said study co-author Lars Forsberg, Associate Professor at the Department of Immunology, Genetics and Pathology at Uppsala University in Sweden. “Examination of mice with mLOY showed increased scarring of the heart, known as fibrosis. We see that mLOY causes the fibrosis which leads to a decline in heart function.”
The results
After their findings, the researchers studied the UK Biobank – a database with genomic and health information from half a million individuals aged 40–70 – and confirmed their findings when they found men with mLOY in their blood displayed an approximately 30% increased risk of dying from heart failure and other types of cardiovascular disease during approximately 11 years of follow-up.
“We also see that men with a higher proportion of white blood cells with mLOY in the blood have a greater risk of dying from cardiovascular disease. This observation is in line with the results from the mouse model and suggests that mLOY has a direct physiological effect also in humans,” Forsberg explained.