Fig. 6

PSCI-associated gut microbiota promotes hippocampal apoptosis and thalamic Aβ deposition. The gut microbiota of PSCI patients is hallmarked by an increased abundance of Enterobacteriaceae and a decreased level of butyrate, which result in a disrupted gut barrier. The LPS constantly travels through the leaky gut into circulation, causing a chronic peripheral inflammation. The continuous inflammation destroys the integrity of BBB, leading to constant infiltration of peripheral LPS and inflammatory cytokines, which promote the neuronal apoptosis in the CA1 region of hippocampus, a brain region that is critical for the cognition. In addition, the low-grade chronic inflammation in the brain promotes the deposition of Aβ plaque in the thalamus, a toxic chemical that is associated with cognitive impairment