Background: Characteristic neuropathologic features of dementia in the human brain, including β-Amyloid (Aβ) in extracellular plaques and phosphorylated tau (pTau181) in neurofibrillary tangles, have been identified in older cats. However, these changes have not yet been directly correlated to clinical signs associated with feline cognitive dysfunction syndrome (FCDS).
Objective: Determine the association between FCDS and biomarkers of dementia-related neurodegeneration in geriatric cats. Methods/Materials: Owners completed a FCDS questionnaire and plasma samples were assayed for dementia-associated biomarkers [Aβ40, Aβ42, pTau181, neurofilament light chain (NfL), and glial fibrillary acidic protein (GFAP)]. Geriatric cats ≥ 12 years of age had biochemistry, CBC, urinalysis, total T4, blood pressure, and neurologic and ophthalmologic examinations performed to screen for comorbidities. Young cats ≤ 6 years old underwent neurologic examinations and evaluation.
Results: One hundred and three geriatric cats and 31 young cats were prospectively enrolled. A significant positive correlation was identified between both Aβ40 and NfL plasma concentrations and FCDS survey scores (95% Confidence Interval, 0.012-0.359 and 0.145-0.470, respectively). Positive correlations were also identified between Aβ42 and GFAP plasma concentrations and FCDS survey scores, but were not significant. NfL plasma concentrations showed the strongest association with FCDS scores and the largest difference between geriatric cats with and without comorbidities. pTau181 could not be quantified in feline plasma, serum or CSF samples.
Conclusion: The biomarkers Aβ40, Aβ42, NfL and GFAP were quantified in cat plasma, and Aβ40 and NfL plasma concentrations were significantly correlated with FCDS scores generated from owner survey responses.
