TNF and Alzheimer disease: Elevated TNF-α levels observed in AD patients, even before the onset of cognitive impairment, are known to induce osteoclastogenesis, inhibit bone formation by suppressing Wnt signaling, and accelerate cartilage destruction via production of MMPs and disintegrin and metalloproteinase with thrombospondin motifs (ADAMTSs) (Osta et al., 2014).