MUC2 and Alzheimer disease: Notably, our recent experiments indicatethat the neuroprotective effects of chronic oral d-galactose50 may be, at least partially, attributed to alterationsin the gut microbiome and the content of short-chain fatty acids (SCFAs).51 In the STZ-icv rat model of AD, there was adecrease in the expression of MUC2 (Figure 3), and it is well-established that the microbiotaplays a significant role in regulating mucus secretion as well asthe expression of MUC2,52,53 the primary mucin producedby intestinal epithelial cells.