Hibernation delays biological aging in bats
The most common bat in the United States, the great brown bat, has an unusually long lifespan of up to 19 years. A new study led by researchers at the University of Maryland identifies one of the secrets to this bat’s exceptional longevity: hibernation.
“Hibernation allows bats, and presumably other animals, to remain in northern or very southern regions where there is no food in winter,” said the study’s senior author, UMD Biology Professor Gerald Wilkinson. “Hibernators tend to live much longer than migratory birds. We knew that, but we didn’t know if we would detect changes in epigenetic age due to hibernation.”
The researchers found that hibernation of a large brown bat extends the epigenetic clock – a biological marker of aging – by three quarters of a year. The study, published in the journal Proceedings of the Royal Society Bon August 10, 2022, scientists from McMaster University and the University of Waterloo, both in Ontario, Canada, were also there.
They analyzed small tissue samples taken from the wings of 20 large brown bats (Eptesicus fuscus) during two periods: in the winter when they were hibernating and in the summer when they were active. The bats, kept in a research colony at McMaster University, ranged in age from less than 1 year old to just over 10 years old.
After the samples were collected, the researchers measured changes in DNA methylation — a biological process linked to gene regulation — between samples taken from the same animal during active and hibernation periods. They found that changes in DNA methylation occurred at certain sites in the bat’s genome, and these sites appeared to affect metabolism during hibernation.
“It’s pretty clear that the sites that decrease methylation in winter are the ones that seem to have an active effect,” Wilkinson said. “Many of the genes closest to them are known to be involved in regulating metabolism, so presumably they keep metabolism low.”
Some of these genes are the same ones Wilkinson and fellow researchers identified as “longevity genes” in a previous study. Wilkinson said there is significant overlap between the hibernation genes and the longevity genes, further emphasizing the link between hibernation and longer lifespan.
The earlier study also established the first epigenetic clock for bats, capable of accurately predicting the age of any bat in the wild. That clock was applied to this latest study, allowing the researchers to show that hibernation lowers a bat’s epigenetic age compared to a non-hibernating animal of the same age.
Studies like these help explain why bats have longer lifespans than expected for a small mammal the size of a mouse. However, they also raise new questions.
“We still don’t really understand why some bats can live very long and others can’t,” Wilkinson said. “We’ve shown that the very long-lived ones all share the ability to hibernate, or often go into sedation. That seems to be a corollary, but it’s not enough because hibernating rodents don’t live 20 years.”
Wilkinson said he plans a follow-up study to compare epigenetic aging in large brown bats in Canada, where they hibernate, with the same species in Florida, where they don’t hibernate. With this, Wilkinson hopes to get an even clearer picture of the role hibernation plays in extending lifespan.
The article, titled “Big brown bats experience slower epigenetic aging during hibernation,” was published in Proceedings of the Royal Society B on August 10, 2022.
Accurate aging of wild animals thanks to first epigenetic clock for bats
Large brown bats experience slower epigenetic aging during hibernation, Proceedings of the Royal Society B: Biological Sciences (2022). DOI: 10.1098/rspb.2022.0635. rspb.royalsocietypublishing.or … .1098/rspb.2022.0635
Quote: Hibernation Slows Biological Aging in Bats (2022, August 9,), retrieved August 9, 2022 from https://phys.org/news/2022-08-hibernation-biological-aging.html
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