The Greenland shark: A new challenge for the oxidative stress theory of ageing?

Abstract

21The free radical theory of ageing predicts that long-lived species should be more 22 resistant to oxidative damage than short-lived species. Although many studies support 23 this theory, recent studies found notable exceptions that challenge the generality of this 24 theory. In this study, we have analysed the oxidative status of the Greenland shark 25 (Somniosus microcephalus), which has recently been found as the longest living 26 vertebrate animal known to science with a lifespan of at least 272 years. As compared to 27 other species, the Greenland shark had body mass-corrected values of muscle 28 glutathione peroxidase and red blood cells protein carbonyls (metric of protein oxidative 29 damage) above 75 percentile and below 25 percentile, respectively. None of the 30 biochemical metrics of oxidative status measured in either skeletal muscle or red blood 31 cells were correlated with maximum lifespan of species. We propose that the values of 32 metrics of oxidative status we measured might be linked to ecological features (e.g., 33adaptation to cold waters and deep dives) of this shark species rather to its lifespan. 34 35

Exploring the role of host specialisation and oxidative stress in interspecific lifespan variation in subtropical tephritid flies

“…However, long-lived species from the genus Ceratitis, such as C. cosyra and C. scaevolae, did not have outstanding TAC in comparison with the other species with shorter lifespans. This aligns with findings in vertebrates where exceptional lifespan is not associated with exceptional antioxidant protection [16][17][18] . Nevertheless, average lifespan significantly increased with TAC, and this was not due to the phylogenetic relationship between species.…”

“…These assumptions are often supported at a sex-specific level, with the longer-lived sex often having lower oxidative damage 14,15 . However, some exceptions have been found in very long-lived species which have neither high antioxidant protection nor low oxidative damage [16][17][18] . While a number of comparative studies support the FRTA, experimental work has generated equivocal results.…”

Nontraditional systems in aging research: an update

“…Comparative analysis with other species showed that these sharks display high values of GPx in muscles and low levels of carbonylated proteins in erythrocytes, suggesting a beneficial proportion of redox parameters. At the same time, oxidative status was not correlated with longevity, which is instead a form of adaptation to specific environmental conditions [123]. Despite the fascinating value of the Greenland shark's lifespan, neither cellular nor molecular determinants of this phenomenon have been identified.…”

Long-lived animals with negligible senescence: clues for ageing research

“…When differences in markers of oxidative stress were compared in mollusc species with a six-fold difference in life span, Gruber et al (50) reported correlations between DNA oxidation and biological, but not chronological age, implying that nucleic acid oxidation reflected intrinsic ageing mechanisms. On the other hand, since surrogate markers of oxidative damage in red blood cells and muscle did not correlate to lifespan in Greenland sharks, the free radical theory of ageing may not apply to all long-lived species (51). In the case of the Greenland shark, oxidative status may rather be shaped to the life in cold and deep artic water (51).…”

“…On the other hand, since surrogate markers of oxidative damage in red blood cells and muscle did not correlate to lifespan in Greenland sharks, the free radical theory of ageing may not apply to all long-lived species (51). In the case of the Greenland shark, oxidative status may rather be shaped to the life in cold and deep artic water (51).…”