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A tissue collection of Greenland sharks.
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Credit: Ewan Camprisson
New experimental research indicates that metabolic activity of muscles may be a key factor in the extraordinary longevity of the Greenland shark, the world’s oldest vertebrate species. These findings may have applications in protecting this vulnerable species against climate change, and even for human cardiovascular health.
Greenland shark (Somniosus microcephalus) is the longest-lived vertebrate animal, with a lifespan of at least 270 years and potentially more than 500 years. “We want to understand what adaptations allow them to live such long lives,” says Euan Camplison, a doctoral student at the University of Manchester, UK.
Previously, it was thought that this longevity was due to the cold environment the sharks live in and minimal movement, but the factors behind this species’ extreme longevity appear to be much more complicated, leading Camplison and his team to investigate alternative theories.
“Most species experience changes in their metabolism as they age,” Camplison said, “and we want to determine whether Greenland sharks also show these traditional signs of aging, or whether their metabolism remains constant over time.”
To measure the sharks’ metabolism, Camplison and his team performed enzyme analyses on samples of preserved muscle tissue from Greenland sharks. They measured the metabolic activity of these enzymes using a spectrophotometer across a range of shark ages and environmental temperatures.
Surprisingly, Camplison and his team found no significant changes in muscle metabolic activity with age, suggesting that their metabolism doesn’t seem to decline over time, which may play an important role in their longevity. “This is quite different from most animals, where we see some changes in metabolic enzyme activity as we age,” he says. “This result supports our hypothesis that Greenland sharks don’t show the same traditional signs of aging as other animals.”
The study’s results also show that metabolic enzymes in Greenland sharks are significantly more active at higher temperatures. “This suggests that shark red muscle metabolism is not specifically adapted to the polar environment, otherwise we would expect less significant differences in activity with temperature,” Camplison says.
In a world where the climate is changing rapidly, the least adaptable, long-lived species may be the most at risk of extinction. “Female Greenland sharks may not reach sexual maturity until they are 150 years old, and their long generation times make them much less able to adapt to human-induced changes to their environment,” Camplison says.
Camplison plans to test more enzymes and tissue types to better understand the sharks’ metabolic activity. “My ultimate goal is to conserve this species, and the best way to do that is to understand them better,” he says.
Camplison is also interested in how this research can help us understand heart disease in humans. “By studying Greenland sharks and their hearts, we may be able to better understand our own cardiovascular health,” he says. “These problems become increasingly common and severe as we age.”
The research will be presented at the Society for Experimental Biology annual meeting, taking place February 2-5 in Prague.Number July 2024.
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