The secret to longevity? Ask a yellow-bellied marmot

Date:
March 7, 2022
Source:
University of California - Los Angeles
Summary:
A new study shows that aging slows to a crawl when yellow-bellied
marmots hibernate. These large ground squirrels are able to
virtually halt the aging process during the seven to eight months
they spend hibernating in their underground burrows, the researchers
report. The study is the first to analyze the rate of aging among
marmots in the wild.



FULL STORY ==========================================================================
What if you were told there was a completely natural way to stop your
body from aging? The trick: You'd have to hibernate from September to
May each year.


========================================================================== That's what a team of UCLA biologists and colleagues studying
yellow-bellied marmots discovered. These large ground squirrels are able
to virtually halt the aging process during the seven to eight months
they spend hibernating in their underground burrows, the researchers
report today in the journal Nature Ecology and Evolution.

The study, the first to analyze the rate of aging among marmots in the
wild, shows that this anti-aging phenomenon kicks in once the animals
reach 2 years old, their age of sexual maturity.

The researchers studied marmot blood samples collected over multiple
summer seasons in Colorado, when the animals are active above ground,
to build statistical models that allowed them to estimate what occurred
during hibernation. They assessed the biological aging of the marmots
based on what are known as epigenetic changes -- hundreds of chemical modifications that occur to their DNA.

"Our results from different statistical approaches reveal that epigenetic
aging essentially stalls during hibernation," said lead author Gabriela
Pinho, who conducted the study as a UCLA doctoral student advised by
Daniel Blumstein and Robert Wayne, professors of ecology and evolutionary biology. "We found that the epigenetic age of marmots increases during
the active season, stops during hibernation and continues to increase
in the next active season." This process, the researchers said, helps
explain why the average life span of a yellow-bellied marmot is longer
than would be expected from its body weight.



========================================================================== Hibernation, an evolutionary adaptation that allows animals to survive
in harsh seasonal environments where there is no food and temperatures
are very low, is common among smaller mammals, like marmots, native to
the mountainous western regions of the U.S. and Canada.

The marmots' hibernation alternates between periods of metabolic
suppression that last a week or two and shorter periods of increased metabolism, which generally last less than a day. During metabolic
suppression, their breathing slows and their body temperature drops dramatically, to the point that "they feel like fuzzy, cold rocks,"
Blumstein said.

In addition, they use a miniscule amount of energy, burning about a single
gram of fat a day. "That's essentially nothing for a 5,000-to-6,000-gram
(11-13 lbs.) animal," Pinho noted. This allows them to save energy and
survive long periods without food.

During their active summer season, marmots eat a lot, doubling their
weight so that they have sufficient fat to survive the next hibernation
period.

All of these hibernation-related conditions -- diminished food
consumption, low body temperature and reduced metabolism -- are known
to counter the aging process and promote longevity, the researchers
said. This delayed aging is likely to occur in other mammals that
hibernate, they said, because the molecular and physiological changes
are similar.



========================================================================== "This study is the closest scientists have gotten to showing that
biological processes involved in hibernation are important contributors
to their longer- than-expected life span based on their body weight,"
said Pinho, now a researcher with the nonprofit Institute of Ecological Research's Lowland Tapir Conservation Initiative in Brazil.

"The fact that we are able to detect this reduced aging during
hibernation in a wild population means the effect of hibernation on
slowing aging is really strong," said Blumstein, a member of the UCLA
Institute of the Environment and Sustainability and a senior author of
the study. "This study was possible only because we had access to blood
samples from free-living animals whose ages are known. Not many wild populations have detailed information about individual chronological
age, and this reinforces the importance of long-term field projects."
There may be biomedical advantages to inducing hibernation conditions
in humans or human cells, the researchers said -- to preserve organs
for transplantation, for example, or as part of long-term space missions.

For the current publication, Pinho and her colleagues studied 73
female yellow- bellied marmots throughout their lives and collected
blood samples every two weeks over 14 active seasons, analyzing them
regularly. The marmots' chronological age was calculated based on the
date at which juveniles first emerged from their natal burrows. (The
age of male marmots is difficult to determine, the researchers said,
because they often migrate from one area to another.) The research
is part of part of a 60-year study of yellow-bellied marmots based at
the nonprofit Rocky Mountain Biological Laboratory in Colorado and was
funded by Brazil's Science Without Borders program, part of the country's National Counsel of Technological and Scientific Development, and the
National Geographic Society, a Rocky Mountain Biological Laboratory
research fellowship and the National Science Foundation.

Other senior study authors are Robert Wayne; Matteo Pellegrini, a UCLA professor of molecular, cell and developmental biology; Steve Horvath,
a professor of human genetics and biostatistics at UCLA's Fielding
School of Public Health who developed the "epigenetic clock" in 2013;
Julien Martin from Canada's University of Ottawa; and Sagi Snir from
Israel's University of Haifa.

The authors received insights from UCLA's Statistical Consulting Group.

========================================================================== Story Source: Materials provided by
University_of_California_-_Los_Angeles. Original written by Stuart
Wolpert. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Gabriela M. Pinho, Julien G. A. Martin, Colin Farrell, Amin Haghani,
Joseph A. Zoller, Joshua Zhang, Sagi Snir, Matteo Pellegrini,
Robert K.

Wayne, Daniel T. Blumstein, Steve Horvath. Hibernation slows
epigenetic ageing in yellow-bellied marmots. Nature Ecology &
Evolution, 2022; DOI: 10.1038/s41559-022-01679-1 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/03/220307131958.htm

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