From companionship to science: the importance of dogs in advancing translational research on Alzheimer's disease – a scoping review

Rodent and primate models have advanced Alzheimer's disease (AD) research but are limited by anatomical differences, engineered pathologies, and aging trajectories that diverge from human neurodegeneration. Conversely, companion dogs naturally develop canine cognitive dysfunction (CCD), a progressive condition with behavioral and neuropathological features closely paralleling AD. This scoping review systematically maps the current literature on CCD, encompassing risk factors, clinical presentation, diagnostic frameworks, and underlying mechanisms, with the aim of critically appraising its translational relevance to AD. Findings reveal overlapping domains between CCD and AD, including cognitive decline, neuroinflammation, amyloid and tau pathologies, and modifiable risk factors. However, diagnostic criteria remain heterogeneous, and mechanistic insights are still fragmented, posing challenges for the model's broader application. This review highlights the strengths and limitations of CCD as a natural model of dementia, identifies knowledge gaps, and outlines future research directions to enhance its utility for advancing AD research.