A recent study shows that the extraordinary lifespan of the Greenland shark, the oldest living vertebrate species, may be significantly influenced by muscle metabolic activity.
These insights could be crucial for protecting this species, which is facing threats from climate change, and could even provide new opportunities to improve cardiovascular health in humans.
“Aging is a very complex system, and I think many factors could play a role in the extreme longevity of the Greenland sharks,” Ewan Camplisson, the lead researcher, told Interesting technique (IE).
Greenland sharks (Nightcap microcephaly) hold the record for the longest-lived vertebrates, with an expected lifespan of at least 270 years and the potential to live longer than 500 years.
Research into the lifespan of Greenland sharks
Previously, it was thought that the remarkable lifespan of Greenland sharks was mainly due to their cold habitat and limited physical activity. However, the reasons behind their extraordinary lifespan appear to be considerably more complex.
“Most species show variation in their metabolism as they age,” Camplisson says. To assess the sharks’ metabolism, the researchers performed enzyme assays on preserved Greenland shark muscle tissue samples, evaluating the metabolic activity of these enzymes across different ages and environmental temperatures.
Unexpectedly, the results showed no significant differences in muscle metabolic activity across ages, indicating that the sharks’ metabolism does not decline over time. This finding suggests that stable metabolic activity may be a crucial factor in their longevity.
“By showing that their [Greenland sharks’] “The metabolism of their red muscles doesn’t seem to change with age, I think this shows that the shark has a suite of adaptations that together lead to its long lifespan,” Camplisson says. I.E
“The fact that Greenland sharks show no change in activity as they age suggests that they may not have the same gradual build-up of damage to their metabolic enzymes and therefore do not need to adapt their metabolism as other animals, such as humans, would,” he added.
The results of the study also indicate that the metabolic enzymes of Greenland sharks show significantly higher activity at elevated temperatures. “This would suggest that the shark’s red muscle metabolism is not specially adapted to the polar environment,” says Camplisson.
In a rapidly changing climate, species with long lifespans and limited adaptability are at greater risk of extinction. Female Greenland sharks, which may not reach sexual maturity until they are 150 years old, have longer generation times that significantly reduce their ability to adapt to human-induced environmental changes.
When it comes to conservation, Camplisson, aside from the obvious calls to lower ocean temperatures, has some suggestions for the Greenland shark. “A more specific plan for the Greenland shark would be to control the expansion of fishing in Arctic waters. With the loss of Arctic ice, new fishing areas are opening up and these need to be closely monitored to determine the extent of bycatch of Greenland sharks,” he says.
“This monitoring would also provide insight into where populations are in the greatest numbers and to track whether warming waters are forcing sharks into a shrinking area of cold water,” Camplisson adds.
What does this have to do with human health?
Studying cardiovascular and metabolic activity in sharks could lead to interesting research directions regarding human health. “The cardiovascular system of a shark is very different from that of humans. It is therefore not easy to make direct comparisons between the two complete systems,” Camplisson believes.
“We hope that this and future work will allow us to determine what adaptations to the metabolic enzymes and metabolism in general allow them to have such consistent activity with age. An important factor to investigate is mitochondrial dysfunction and whether Greenland sharks show signs of this at all,” he concludes.
This research will be presented at the annual conference of the Society for Experimental Biology in Prague on 2-5e July 2024.
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Srishti Gupta Srishti studied English Literature at Delhi University and has since realised that it’s not her cup of tea. She has edited in every conceivable space and content type, from children’s books to magazine articles. She enjoys popular culture, reading contemporary fiction and non-fiction, crafting, and spending time with her cats. With a keen interest in science, Srishti is particularly drawn to beats covering medicine, sustainability, genetic studies, and all things biological.