MAPT and Cognitive impairment: We demonstrated that dysbiosis in gut microbiota increased serum levels of tau protein, β-amyloid, and LPS as well as stool curli protein during mild cognitive impairment and dementia, these results were associated with an imbalance in the intestinal microbiota that increased E.coli abundance, which produces the amyloid curli protein responsible for the formation of neurofibrillary tangles.