Hematologic and blood biochemical variables of captive chimpanzees: Cross-sectional and longitudinal analyses

Hematologic and blood biochemical variables are of great importance in medi cal and veterinary practice. In addition, these analytes may have significa nce as potential biomarkers of aging, Previous reports on normative values of these variables in the chimpanzees are based on cross-sectional studies that; did not include individuals of advanced age. To address this omission , we performed cross-sectional and longitudinal analyses of hematologic and blood biochemical data collected from chimpanzees over a g-year period. On e-hundred forty-six females and 106 males of ages representing the entire l ife span of the species were studied. We derived normative cross-sectional values of 14 commonly measured hematologic and 20 blood biochemical variabl es, which should provide a useful reference for clinical blood studies in c himpanzees. In addition, we found in a cross-sectional regression analysis of our data that most analytes varied significantly between males and femal es, and that they varied markedly with age. Most variables had year-to-year consistency within the same individuals, as indicated by statistically sig nificant intra-year correlation coefficients. Finally, we performed a longi tudinal analysis of the analytes in chimpanzees by calculating the slopes a nd intercepts of the best-fitting trend line for each individual. The resul ting slopes were analyzed by sex and by decade of age of subjects to determ ine whether trends were consistent. Consistent trends detected in the longi tudinal analysis were usually restricted to the first decade of life, and t hus represented maturational processes. The overall lack of within-animal t rends covering all or most of the period from early adulthood through old a ge in this 9-year study suggests that a longer period of follow-up than use d here may be required to document senescence-related changes.