Surgery-induced gut microbial dysbiosis promotes cognitive impairment in aged mice

Perioperative neurocognitive disorders (PND) are the most common postoperative complications with few therapeutic options. Disruption of the gut microbiota has been associated with PND; however, the specific changes in age-associated gut microbiota in PND and the underlying mechanisms remain largely unknown.We showed that surgery-induced cognitive impairment occurs mainly in aged mice. The gut microbiota were significantly altered in young and aged mice that underwent surgical injury. Moreover, the results from fecal microbiota transplantation (FMT) in aged mice that underwent surgical injury showed that FMT from young mice displayed a better learning and cognitive ability than those receiving old mouse feces, reduced neuroinflammation, and preserved neuroplasticity. Furthermore, FMT from young mice to aged mice that underwent surgical injury increased the richness and diversity of the gut microbiota. Most notably, the abundance of g_Akkermansia increased significantly. We demonstrated that the occurrence of PND is significantly associated with gut microbiota disruption. Normalization of gut microbiota reduces surgically induced cognitive impairment.