OLD DOG - Validating the dog as an animal model for human aging studies

: Companion dogs represent a valuable and emerging translational model for human aging, as they share the human environment, receive comparable medical care - yet have much shorter lifespans. Despite their potential, a validated set of canine biomarkers of aging has not yet been established. The OLD-DOG Project, launched in 2023 at the University of Padua's Veterinary Teaching Hospital, is a 30-month prospective study designed to identify and validate biomarkers of aging in companion dogs and to assess their predictive value for healthspan and lifespan, thereby evaluating the suitability of dogs as models for human aging research. A cohort of 209 privately owned dogs aged  ≥ 5 years was enrolled and underwent comprehensive evaluations every six months, including clinical examinations, physical fitness testing, blood and fecal sampling, and owner questionnaires. Collected data encompass physiological, biochemical, hematological, and behavioral parameters, as well as microbiota profiles, telomere length, and DNA methylation patterns. Surplus biological material is stored to establish a long-term biobank. Preliminary cross-sectional analyses have identified consistent age-related patterns across multiple domains, including hematological and biochemical indices, inflammatory markers, and measures of physical and cognitive performance. Ongoing longitudinal analyses aim to determine the predictive value of these candidate biomarkers for morbidity and mortality, as well as to assess the influence of environmental and lifestyle factors on aging trajectories. Ultimately, the project seeks to construct an integrative model of biological age in dogs, thereby strengthening their value as a robust translational model for human aging research.