Consistent with the findings of our study, Ling et al. reported that the abundant butyrate-producing genera such as Faecalibacterium and Gemmiger decreased significantly, which was positively correlated with clinical indicators such as cognitive function scores, and were negatively correlated with inflammatory cytokines, such as TNF-α and chemokines in Alzheimer’s Disease patients (44). Here, TNF is linked to Alzheimer disease.