A paper published on Thursday in the journal “Science” provided details regarding a brand-new study done on male mice about the effects of gradual loss of the Y chromosome in males. Scientists observed a group of male mice that lost their Y chromosomes due to genetic engineering. The researchers found that the loss caused a shortened life span and a higher risk of getting cancer and other heart diseases in the mice because of scar tissue buildup. The results of the study lead researchers and scientists to believe that the same consequences of losing the Y chromosome in male mice can apply to human men, although there is no definitive answer yet.
The loss of Y chromosomes occurs naturally in men as they age, and there aren’t other ways to reduce the risk besides not smoking. Loss of the chromosome is not linked to testosterone levels in men, making testosterone supplements useless for the condition. Studies show that at age 70, a minimum of 40% of men lose parts of their Y chromosomes in blood cells; at age 93, the number is about 57%. Referred to as mosaic loss of chromosome Y, the chromosome dissolves when the process of cell division removes it from the cells.
In 2013, researcher Lars Forsberg from Uppsala University first stumbled across this unknown fascinating topic after hearing about the significance of Y chromosomes in fruit flies from a former professor in Uppsala, Sweden. Before, Dr. Forsberg had thought the Y chromosome was a genetic wasteland like many others because almost all the genes used by male cells were from the other chromosome in men, the X.
Dr. Forsberg researched the Uppsala Longitudinal Study of Aging Men conducted on 1,153 men and found proof that the Y chromosome was important. “I had the data in a few hours, and I was like, ‘Wow,’ I saw that men with loss of Y in a large proportion of their blood cells survived only half as long, 5.5 years versus 11.1 years,” he said, “You can imagine my surprise. Of course, I redid everything.”
Dr. Forsberg published his findings in 2014, stating that the loss of the Y chromosome was linked with higher death rates and more cancer diagnoses in “Nature Genetics.” He then founded the company “Cray Innovation,” which would focus on testing men for the loss of Y chromosomes. Meanwhile, his paper took the lead for 20 more independent reports on the same topic, some of which included more research associating many age-related diseases like blood cancers and lid tumors with the vanishing of Y chromosomes.
Dr. Forsberg’s work drew another fellow scientist that studied CHIP, a condition related to aging that causes a greater risk of cancer and heart disease because there is an increased risk of cancer mutations in the blood cells. The director of the Hematovascular Biology Center at the University of Virginia School of Medicine, Kenneth Walsh, had wondered about the other genetic alternations related to aging besides CHIP and experimented with mice. He described how the mice were during the experiment saying, “they aged poorly.” Specifically, scar tissue was found not only in the heart but also in the kidney and lungs. They also contracted the not well-known non-ischemic heart failure. Mental abilities also deteriorated in the mice.
Dr. Walsh and Dr. Forsberg studied UK Biobank info on 223,173 men. They found that men experiencing loss of Y chromosomes would have a 41% increased risk of death from all causes and a 31% increased risk of dying from cardiovascular disease.
Even though the discovery in mice could have a lot of significance if proven true in humans, the lack of evidence causes controversy among various scientists internationally. The director of the cancer epidemiology and genetics division at the National Cancer Institute, Dr. Stephen Chanock, said, “the over the interpretation of these data for monetary purposes worries me deeply.” On the other side, Dr. Ross Levine, the deputy physician in chief for translational research at Memorial Sloan Kettering Cancer Center, said, “The authors really nailed it here. It’s super important work.”
Sources: https://www.nytimes.com/2022/07/14/health/y-chromosome-heart-failure.html
The loss of Y chromosomes occurs naturally in men as they age, and there aren’t other ways to reduce the risk besides not smoking. Loss of the chromosome is not linked to testosterone levels in men, making testosterone supplements useless for the condition. Studies show that at age 70, a minimum of 40% of men lose parts of their Y chromosomes in blood cells; at age 93, the number is about 57%. Referred to as mosaic loss of chromosome Y, the chromosome dissolves when the process of cell division removes it from the cells.
In 2013, researcher Lars Forsberg from Uppsala University first stumbled across this unknown fascinating topic after hearing about the significance of Y chromosomes in fruit flies from a former professor in Uppsala, Sweden. Before, Dr. Forsberg had thought the Y chromosome was a genetic wasteland like many others because almost all the genes used by male cells were from the other chromosome in men, the X.
Dr. Forsberg researched the Uppsala Longitudinal Study of Aging Men conducted on 1,153 men and found proof that the Y chromosome was important. “I had the data in a few hours, and I was like, ‘Wow,’ I saw that men with loss of Y in a large proportion of their blood cells survived only half as long, 5.5 years versus 11.1 years,” he said, “You can imagine my surprise. Of course, I redid everything.”
Dr. Forsberg published his findings in 2014, stating that the loss of the Y chromosome was linked with higher death rates and more cancer diagnoses in “Nature Genetics.” He then founded the company “Cray Innovation,” which would focus on testing men for the loss of Y chromosomes. Meanwhile, his paper took the lead for 20 more independent reports on the same topic, some of which included more research associating many age-related diseases like blood cancers and lid tumors with the vanishing of Y chromosomes.
Dr. Forsberg’s work drew another fellow scientist that studied CHIP, a condition related to aging that causes a greater risk of cancer and heart disease because there is an increased risk of cancer mutations in the blood cells. The director of the Hematovascular Biology Center at the University of Virginia School of Medicine, Kenneth Walsh, had wondered about the other genetic alternations related to aging besides CHIP and experimented with mice. He described how the mice were during the experiment saying, “they aged poorly.” Specifically, scar tissue was found not only in the heart but also in the kidney and lungs. They also contracted the not well-known non-ischemic heart failure. Mental abilities also deteriorated in the mice.
Dr. Walsh and Dr. Forsberg studied UK Biobank info on 223,173 men. They found that men experiencing loss of Y chromosomes would have a 41% increased risk of death from all causes and a 31% increased risk of dying from cardiovascular disease.
Even though the discovery in mice could have a lot of significance if proven true in humans, the lack of evidence causes controversy among various scientists internationally. The director of the cancer epidemiology and genetics division at the National Cancer Institute, Dr. Stephen Chanock, said, “the over the interpretation of these data for monetary purposes worries me deeply.” On the other side, Dr. Ross Levine, the deputy physician in chief for translational research at Memorial Sloan Kettering Cancer Center, said, “The authors really nailed it here. It’s super important work.”
Sources: https://www.nytimes.com/2022/07/14/health/y-chromosome-heart-failure.html
