This study investigated the role of tau protein, β-amyloid, LPS (lipopolysaccharide), and curli protein in elderly adults with MCI or D and the contribution of gut microbiota. Four groups were studied: young subjects, healthy adults over 60 (A), elderly adults with MCI (MCI), and elderly adults with dementia (D). Results showed that with increasing age, tau protein, β-amyloid, and LPS significantly increased in serum during MCI and D, associated with increased E. coli (synthesizing curli protein), potentially promoting amyloid protein aggregation. Rats showed increased curli protein in the brain during aging. Cognitive impairment and dementia are partly due to gut microbiota-brain axis alteration via increased curli protein and LPS, leading to increased tau and β-amyloid protein.

Mónica Sánchez-Tapia, Alberto Mimenza-Alvarado, Lizbeth Granados-Domínguez, Adriana Flores-López, Adriana López-Barradas, Victor Ortiz, Claudia Pérez-Cruz, Hilda Sánchez-Vidal, Julieta Hernández-Acosta, José Alberto Ávila-Funes, Martha Guevara-Cruz, Armando R Tovar, Nimbe Torres