Correlations between serum levels of beta amyloid, cerebrospinal levels of tau and phospho tau, and delayed response tasks in young and aged cynomolgus monkeys ( M acaca fascicularis )

Background In an attempt to explore cynomolgus monkeys as an animal model for A lzheimer's disease, the present study focused on the A lzheimer's biomarkers beta amyloid 1–42 ( A β 42 ) in serum, and total tau (t‐tau) and phosphorylated tau (p‐tau) levels in cerebrospinal fluid. Methods We measured biomarker levels in Y oung and A ged cynomolgus monkeys and correlated these with performance on three delayed response tasks. Results The A β 42 concentration of the A ged monkeys was significantly lower than in the Y oung subjects, while the t‐tau and p‐tau did not significantly differ between the groups. The Y oung subjects performed significantly better than the A ged individuals on the memory tests. Only A β 42 levels were significantly correlated with performance in the three delayed response tasks. Conclusions Circulating A β 42 levels were lower in A ged monkeys and were correlated with inferior performance on delayed response tasks in A ged animals; therefore, both measures may be useful in establishing cynomolgus monkeys as models for studies of AD .