Aging and sex affect soluble alpha klotho levels in bonobos and chimpanzees.
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ABSTRACT: 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 (?-Kl). Both sexes show an age-related decline in ?-Kl, but throughout life women have higher levels than men of the same age. Sex differences in ?-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 ?-Kl levels is rare and restricted to experimental work. Our cross-sectional study is the first on ?-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.We measured serum ?-Kl levels of 140 subjects from 16 zoos with an ELISA to examine if ?-Kl levels reflect this difference in life expectancy.In both species and in both sexes, ?-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 ?-Kl levels than males, a difference that corresponds to the pattern found in humans. In chimpanzees, we found the opposite: males had higher ?-Kl levels than females.We suggest that contrasting sex differences in adult ?-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 ?-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 ?-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.
<h4>Background</h4>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 (α-Kl). Both sexes show an age-related decline in α-Kl, but through ...[more]
