Sleeve gastrectomy improves cognition by enhancing central ERK/CREB/BDNF pathway through increased GIP secretion

Sleeve gastrectomy (SG) was used to probe the gut-brain axis in Alzheimer's disease (AD). In APP/PS1/Tau triple transgenic mice, SG improved glucose tolerance and insulin sensitivity without lasting effects on body weight or food intake. SG significantly improved cognitive performance and reduced anxiety-like behavior, attenuated neuronal damage and pTau accumulation in the hippocampal CA3 region, and increased both peripheral levels and hippocampal immunoreactivity of GIP and GLP-1 along with ERK/CREB/BDNF pathway activity. In HT22 cells, GIP receptor knockdown exacerbated Aβ-induced pTau and suppressed this pathway, whereas GLP-1 acted synergistically. These findings indicate that SG could improve cognition in non-obese AD mice largely through GIP/GLP-1 signaling rather than metabolic changes, supporting dual incretin targeting as a therapeutic strategy for AD.