Approximately 35% of the canine population in the US and other developed nations
is considered overweight or obese (Lund et al. 2006). Similar to humans, canine
obesity is a risk factor for numerous disease states, including metabolic
abnormalities, endocrinopathies, orthopedic disorders, cardiorespiratory disease,
urogenital diseases, and cancer (German 2006). Plasma metabolic and hormonal
profiles of obese dogs have been reported (Yamka et al. 2006), but metabolic and
transcriptomic changes within tissues of lean vs. obese dogs have not been
extensively studied. Because aged animals are believed to have an increased
susceptibility to the toxic effects of lipid overload (lipotoxicity) associated with
overnutrition (Slawik and Vidal-Puig 2006), research in aged dogs is needed.