Region-specific age at onset of β-amyloid in dogs

Cortical patterns of β-amyloid (Aβ) deposition were evaluated in 40 beagle dogs ranging in age from 2 to 18 years. Aβ deposition in the prefrontal, occipital, parietal and entorhinal cortices was visualized by using an antibody against Aβ1–42. A logistic regression was used to estimate differences in age-at-onset and rate of deposition of Aβ as a function of brain region. The earliest and most consistent site of Aβ deposition with age was in the prefrontal cortex. Entorhinal Aβ deposition was not consistently observed until the age of 14 years, but was present in a subset of dogs under the age of 14 years. These regional vulnerabilities to Aβ accumulation are similar to those seen in the aging human. By using parameters derived from regression analyses, it may be possible to predict the presence of Aβ within specific brain regions in individual dogs. We propose that these models will be a useful tool to evaluate interventions that delay the age of onset or slow the rate of accumulation of Aβ in the dog.