University of Manchester
Mechanisms Permitting Cardiac Longevity in Greenland Sharks
Lead Researcher: Ewan Camplisson
In 2016 the Greenland shark was found to be the worlds longest living vertebrate with a lifespan of 272 years (Nielsen et al., 2016). Quickly researchers took an interest in the cardiac health of this species, as the two highest causes of human death annually are cardiovascular related (WHO, 2020).
Why should we study Greenland Sharks?
Cardiovascular disease became a leading cause of death in the 20th century (CDC, 1999) however, when age-adjusted deaths are accounted for there has been a decreasing trend in cardiovascular deaths since the 1960s (CDC, 1999). In this same time period the world population has approximately tripled (UN) and therefore even with a decreasing trend in cardiovascular deaths, they still account for the greatest number of mortalities worldwide each year, with just over one quarter of all deaths being attributed to these conditions (BHF, 2024). For this reason, research focused on improving cardiovascular health and further reducing risk of death is of key importance across the globe and will benefit all socio-economic groups and nations.
The Greenland shark offers an interesting animal model to study cardiovascular disease and the decline of heart health with age. Initially it may be suggested that the arctic environment is the primary factor in their longevity. As in colder conditions metabolism is generally reduced and this may allow animals to have slower growth, later reproduction and generally less competition. However, the Greenland shark's metabolism (although low) is within the expected parameters seen within other shark species when temperature and mass are considered (Ste-Marie et al., 2020). This would suggest that their lifestyle is not irregular for a large polar ectotherm and means we need to further investigate what adaptations allow them to have such extreme longevity. This project is attempting to uncover irregularities in the Greenland shark across a range of tissues with the specific goal of determining if they show signs of aging and are we able to utilise these adaptations to improve human health, specifically in older age.
The Greenland shark has been investigated by the Galli lab using a number of techniques:
Current techniques
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Oroboros microrespirometry: Studying metabolism in cardiac tissue and the electron transport chain
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Metabolic enzyme analysis - Studying enzyme activity in liver and red muscle
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CometChip® assay - Studying genomic instability in blood samples
Future techniques:
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qPCR - Studying epigenetic alterations in cardiac tissue.
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Telomere restriction fragment assay - Studying telomere attrition rates in young vs old Greenland sharks.
