• Austad, Steven N (PI)

Project: Research project

Project Details


The proposed research seeks to extend the dietary restriction paradigm of
retarded aging to a marsupial mammal--the Virginia Opossum (Didelphis
virginiana)--which is distantly related to both laboratory rodents and
humans. The extent to which the paradigm is verified in the opossum will
be directly relevant to the probability that retarded aging via dietary
restriction is a general mammalian trait as opposed to a physiological
quirk of murine rodents. Actuarial aging will be measured in two
laboratory populations--a fully-fed (FF) control group and a dietary-
restricted group (DR) that is given an isonutrient diet which contains 70%
of the calories of the FF diet. In addition to actuarial data, relative
aging in the two groups will be assessed by serial monitoring of: (a) the
temporal pattern of reproductive cycling, (b) denaturation time of tail
tendon collagen, (c) glycation of hemoglobin and blood serum protein,
collagen from skin and tendon, (plus postmortem analyses of aorta collagen
and eye lens proteins), and (d) a behavioral strength and agility test.
All of these parameters are known or suspected to be general biomarkers of
aging. In addition, a major goal of the proposal will be the longitudinal
monitoring of serum osteocalcin (a potential early diagnostic parameter
bone pathology), because elderly opossums show postural and gross
morphological changes suggesting extensive bone loss. Also, in order to
assess whether DR is affecting longevity through a reduction of metabolic
rate, three-day metabolic expenditures of all experimental groups will be
assayed using doubly-labelled water. Age-related general pathology will
be assessed by diagnostic blood (hematology and blood chemistry) and urine
analyses, and cause of death determined by standard gross-and
histopathology. A thorough characterization of the opossum's age-related
pathology should also reveal the extent to which it might be a useful
model of specific pathologies.
Effective start/end date9/30/9212/31/95


  • National Institutes of Health: $138,410.00


  • Medicine(all)


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