TREM2 and Cognitive impairment: The results showed that the expression of TREM2 decreased after surgery, accompanied by neuroinflammation, tau hyperphosphorylation, and cognitive disorder; adenovirus as a tool to overexpress TREM2 in AD transgenic mice resulted in the detection of high expression of microglia M2 phenotypic marker Arg1 and synaptophysin DAP12 as well as decreased expression of proinflammatory cytokine (IL‐1β), glycogen synthase kinase‐3β (GSK‐3β) and phosphorylated tau protein.