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Aging and sex affect soluble alpha klotho levels in bonobos and chimpanzees
Background: Throughout life, physiological homeostasis is challenged and the capacity to cope with such challenges declines with increasing age. In many species, sex differences exist in life expectancy. Sex-specific differences have been related to extrinsic factors like mate competition and/or intrinsic proximate mechanisms such as hormonal changes. In humans, an intrinsic factor related to aging is soluble alpha klotho (alpha-Kl). Both sexes show an age-related decline in alpha-Kl, but throughout life women have higher levels than men of the same age. Sex differences in alpha-Kl have been linked to a shorter lifespan, as well as to specific morbidity factors such as atherosclerosis and arteries calcifications. In non-human animals, information on alpha-Kl levels is rare and restricted to experimental work. Our cross-sectional study is the first on alpha-Kl levels in two long-lived species: bonobos (Pan paniscus) and chimpanzees (Pan troglodytes). As in most mammals, female bonobos and chimpanzees have longer life expectancy than males. Methods: We measured serum alpha-Kl levels of 140 subjects from 16 zoos with an ELISA to examine if alpha-Kl levels reflect this difference in life expectancy. Results: In both species and in both sexes, alpha-Kl levels declined with age suggesting that this marker has potential for aging studies beyond humans. We also found species-specific differences. Adult female bonobos had higher alpha-Kl levels than males, a difference that corresponds to the pattern found in humans. In chimpanzees, we found the opposite: males had higher alpha-Kl levels than females. Conclusion: We suggest that contrasting sex differences in adult alpha-Kl levels mirror the dominance relations between females and males of the two Pan species; and that this might be related to corresponding sex differences in their exposure to stress. In humans, higher cortisol levels were found to be related to lower alpha-Kl levels. We conclude that there is great potential for studying aging processes in hominoids, and perhaps also in other non-human primates, by measuring alpha-Kl levels. To better understand the causes for sex differences in this aging marker, consideration of behavioural parameters such as competition and stress exposure will be required as well as other physiological markers.
Tijdschrift: FRONTIERS IN ZOOLOGY
Jaar van publicatie:2018
Trefwoorden:Pan paniscus, Pan troglodytes, Ape, Senescence, Sex-specific, Aging