Hu et al. (2021) found that, in ligature-induced periodontitis (LIP) rats, peripheral blood and the brain showed apparent elevations in inflammatory cytokines (IL-1β, IL-6, IL-8, and IL-21), which are mediated by the signal transducers and activators of transcription 3 (STAT3) signaling pathway. Here, STAT3 is linked to periodontitis.