NAMPT and pulmonary fibrosis: It has shown that NAMPT from damaged lung epithelial cells promotes radiation-induced pulmonary fibrosis 50, 51 and that NAMPT temporally reinforces pro-fibrotic myofibroblast phenotypes in age-dependent pathological fibrosis 52, while another study 53 using mesenchymal stem cells co-cultured with alveolar type II epithelial cells reported that upregulation of NAMPT expression and NAD+ levels in mesenchymal stem cells can slow down the aging of alveolar type II epithelial cells, thus exerting protective effects against lung fibrosis.