Elevated Aβ aggregates in feces from Alzheimer's disease patients: a proof-of-concept study

BackgroundMisfolding and aggregation of amyloid beta (A beta), along with neurofibrillary tangles consisting of aggregated Tau species, are pathological hallmarks of Alzheimer's disease (AD) onset and progression. In this study, we hypothesized the clearance of A beta aggregates from the brain and body into the gut.MethodsTo investigate this, we used surface-based fluorescence intensity distribution analysis (sFIDA) to determine the A beta aggregate concentrations in feces from 26 AD patients and 31 healthy controls (HC).ResultsA beta aggregates were detectable in human feces and their concentrations were elevated in AD patients compared to HC (specificity 90.3%, sensitivity 53.8%).ConclusionThus, fecal A beta aggregates constitute a non-invasive biomarker candidate for diagnosing AD. Whether digestion-resistant A beta aggregates in feces are secreted via the liver and bile or directly from the enteric neuronal system remains to be elucidated.