Discovering new anti-aging secrets from the world’s longest-living vertebrate
IMAGE:
TISSUE COLLECTION FROM A GREENLAND SHARK.
view moreCREDIT: EWAN CAMPLISSON
New experimental research shows that muscle metabolic activity may be an important factor in the incredible longevity of the world’s oldest living vertebrate species – the Greenland shark. These findings may have applications for conservation of this vulnerable species against climate change or even for human cardiovascular health.
Greenland sharks (Somniosus microcephalus) are the longest living vertebrate with an expected lifespan of at least 270 years and possible lifespan beyond 500 years. “We want to understand what adaptations they have that allow them to live so long,” says Mr Ewan Camplisson, a PhD student at the University of Manchester, UK.
Previously it was thought that this long lifespan was due to the shark’s cold environment and minimal movement, but the factors behind this species extreme longevity appear to be far more complex - prompting Mr Camplisson and his team to investigate alternative theories.
“Most species show variation in their metabolism when they age,” says Mr Camplisson. “We want to determine if Greenland sharks also show this traditional sign of aging or if their metabolism remains unaltered over time.”
To measure the metabolism of the sharks, Mr Camplisson and his team conducted enzyme assays on preserved muscle tissue samples from Greenland sharks. They measured the metabolic activity of these enzymes with a spectrophotometer across a range of different shark ages and environmental temperatures.
Surprisingly, Mr Camplisson and his team found no significant variation in muscle metabolic activity across different ages, suggesting that their metabolism does not appear to decrease over time and may play a key role in their longevity. “This is quite different to most animals which tend to show some variation in their metabolic enzyme activity as they age,” he says. “The results support our hypothesis that the Greenland shark does not show the same traditional signs of aging as other animals.”
The results of this study also show that the Greenland shark's metabolic enzymes were significantly more active at higher temperatures. “This would suggest that the shark’s red muscle metabolism is not specially adapted for the polar environment, otherwise we would have expected to see less of a temperature related difference in activity,” says Mr Camplisson.
In a world with a rapidly changing climate, long-lived species that are less able to adapt may be the most at risk of extinction. “A female Greenland shark may not become sexually mature until it is 150 years old and with such a long generation time, the species will have far less of a chance to adapt to anthropogenic changes in their environment,” says Mr Camplisson.
Mr Camplisson plans to test more enzymes and tissue types to gain an even deeper understanding of the shark’s metabolic activity. “My ultimate goal is to protect the species and the best way to do this is to better understand them,” he says.
Mr Camplisson is also interested in the possible applications of this research for our understanding of human heart disease. “By studying the Greenland shark and its heart, we may be able to better understand our own cardiovascular health,” he says. “These are issues that become progressively more common and severe with increasing age.”
This research is being presented at the Society for Experimental Biology Annual Conference in Prague on the 2-5th July 2024.
A new breakthrough in understanding regeneration in a marine worm
IMAGE:
JUVENILE WORM OF THE SPECIES PLATYNEREIS DUMERILII.
view moreCREDIT: © DR. PIERRE KERNER, INSTITUT JACQUES MONOD
The sea worm Platynereis dumerilii is only a few centimetres long but has a remarkable ability: in just a few days, it can regenerate entire parts of its body after an injury or amputation. By focusing more specifically on the mechanisms at play in the regeneration of this worm’s tail, a research team led by a CNRS scientist1 has observed that gut cells play a role in the regeneration of the intestine as well as other tissues such as muscle and epidermis. Even more surprising, the team found that this ability of gut cells to regenerate other tissue varies according to their location: the closer they are to the posterior end of the worm, the greater the variety of cell types they can rebuild2. This study will appear in Development on 2 July.
Scientists carried out these observations by monitoring the outcome of gut cells and proliferative cells that form close to the amputated end of the worm. This was tracked using different markers in particular by fluorescent beads ingested by the worms. Annelids, or ‘segmented worms’, which have only been studied in the last 20 years, are an ideal model for the study of regeneration, a process that is widespread in animals but still mysterious for scientists.
The research team will continue this work to determine whether cell types, other than gut cells, can play a role in regenerating a variety of cell types.
Notes
1 - Working at the Institut Jacques Monod (CNRS/Université Paris Cité). Scientists at Inserm and Université Paris Cité also contributed to this research.
2 - Only cells involved in the nervous system and growth zone of the worm (a ring of stem cells involved in the continuous growth of the animal until it reaches sexual maturity) cannot, it appears, be generated by gut cells found in the posterior end of the worm.
JOURNAL
Development
ARTICLE TITLE
Variations in cell plasticity and proliferation underlie distinct modes of regeneration along the antero-posterior axis in the annelid Platynereis.
ARTICLE PUBLICATION DATE
2-Jul-2024
