Abstract # 47:

Scheduled for Thursday, August 18, 2005 07:00 PM-09:00 PM: (Cambridge/Oxford Room) Poster Presentation

Osteophytosis in Rhesus Macaques (Macaca mulatta)

P. A. Kramer1, L. L. Newell-Morris1,2, P. A. Simkin1 and D. Ingram3
1University of Washington, Box 353100, Seattle, WA 98195-3100, USA, 2WaNPRC, 3NIH/NIA LEG
     Osteoarthritis, a condition strongly associated with aging in human and non-human primates, most clearly manifests in the skeleton as osteophytosis (OST). Despite its strong association with age, the etiology of OST remains obscure. We evaluated OST in the spine and peripheral joints of normally fed and calorically restricted rhesus macaques (Macaca mulatta), enrolled in an ongoing investigation of the long-term effect of caloric restriction on longevity. The animals have been single-caged for over 10 years. OST was evaluated with an atlas-based scoring method where “0” was scored for no involvement and scores of 1, 2 and 3 were minimal, moderate, and severe involvement, respectively. Multiple linear regression was used to evaluate the effects of age, sex, joint location and caloric group on OST, because the groups (males vs. females and calorically restricted vs. non-calorically restricted animals) were not of equivalent age. These variables explained 76% of the variation in score (R2 = 0.76). Not surprisingly, higher OST scores were associated with older ages (P < 0.001) and the spine was involved much more frequently than the peripheral joints (P < 0.001). Male monkeys had higher scores than females across middle and old age (P = 0.009) and the scores of calorically restricted animals were not different from those of normally fed individuals (P = 0.907). As in humans, OST in rhesus macaques appears to be location-specific rather than a systemic condition, indicating that biomechanical effects may be as important in its etiology as generalized senescence.