CTSB and Alzheimer disease: This study reported AD like behaviour following P. gingivalis ATCC 33277T LPS introduction in mice, and above all demonstrated intracellular release of Aβ according to the hypothesis of Hook et al. [46] via the regulated secretory vesicle pathway mediated by cathepsin B (Figure 3), which consolidated the causative relationships of P. gingivalis with AD [55].