New Perspectives on Avian Models for Studies of Basic Aging Processes.

Avian models have the potential to elucidate basic cellular and molecular mechanisms underlying the slow aging rates and exceptional longevity typical of this group of vertebrates. To date, most studies of avian aging have focused on relatively few of the phenomena now thought to be intrinsic to the aging process, but primarily on responses to oxidative stress and telomere dynamics. But a variety of whole-animal and cell-based approaches to avian aging and stress resistance have been developed-especially the use of primary cell lines and isolated erythrocytes-which permit other processes to be investigated.

Ovarian aging in developmental and evolutionary contexts.

Evolutionary theory predicts that aging-related fertility declines result from tradeoffs between reproduction and somatic maintenance. Developmental programs for oogenesis also contribute to variation in aging-related reproductive declines among female vertebrates. Documented reproductive aging patterns in female vertebrates, including humans, are consistent with canonical aging patterns determined developmentally and require no special adaptive explanation.

Naturally long-lived animal models for the study of slow aging and longevity.

Judicious selection of new animal models for the study of basic aging processes must combine feasibility and good use of the comparative method with evidence of antiaging adaptations, like the ability to combat oxidative damage to cells and tissues. A number of vertebrate species already in use or being developed as new biomedical models lend themselves very well to laboratory studies of aging, including small birds, bats, and mole-rats.

Is postmenopausal life-span a gift of modern health or a product of natural selection?

The author discusses how researchers from various scientific disciplines view the origins of and mechanisms (evolutionary as well as physiological) underlying menopause in humans. She describes presentations from a symposium centered around interdisciplinary perspectives on female reproductive aging. Comparative zoology, primatology, and anthropology have much to contribute to our understanding of human menopause; hence the symposium contained speakers representing these subdisciplines, as well as the more typical disciplines of endocrinology and neurobiology.

Reproductive aging in female birds.

Birds are underutilized as animal models for studying the basis of longevity, cellular adaptations for resisting oxidative damage, and delayed reproductive senescence. Reproductive aging patterns in female birds range from slightly slower than those in rodents of similar size to extremely slow or even negligible. The best-studied laboratory bird model of female reproductive aging is the relatively short-lived, rapidly aging domestic laying hen.