Kim Greer

Current Research - Longevity

The long-term objective of this research is to elucidate the biochemical, genetic and physiological mechanisms of aging and age related changes in the domestic dog, Canis familiaris, as an animal model of human aging. The dog is useful for the elucidation of mechanisms associated with aging because among the more than 400 breeds in existence, there is a naturally diverse range of life span. Additionally, the canine sequence has recently been completed and proven to be more similar to the human sequence than is the murine.

Having sequence available, it is now known that each breed consists of a relatively homogeneous population of individuals while the breeds themselves remain heterogeneous enough to be distinguished at the genetic sequence level. Given that life span of the canine is overall relatively short, analysis of a young cohort is possible without making unconfirmed estimates of life span reduction, as it is not entirely possible in primate studies.

The working hypothesis is that oxidative stress contributes considerably to the aging process and specific mechanisms associated with aging and longevity can be determined by investigating the cellular and genetic differences between breeds with naturally diverse life span.

Work In Progress

One of our current projects pertaining to longevity and healthy life span is to determine if oxidative stress levels are correlated to longevity within C. familiaris. Cellular resistance to chemical stressors has been positively correlated with longevity in a variety of mammals, including the hamster, rat, marmoset, rabbit, sheep, pig, cow and human (Kapahi et al, 1999), but similar data is lacking for the dog. Within species comparisons, as opposed to across species comparisons, have likewise demonstrated that cells from long-lived birds have superior defense against oxidative damage when compared to those of short-lived birds (Ogburn et al, 2001). Therefore, we would like to establish the level of oxidative stress resistance in the canine as compared to other mammals, as well as within the species.