TP53 and pulmonary fibrosis: Meanwhile, these multidirectional changes in alveolocytes and cells of mesenchymal origin in conditions of pulmonary fibrosis in both cases are associated with cellular aging and changes in gene expression, including PAI-1 and p53 [103], although detailed mechanisms of acquisition by various cellular subpopulations of different sensitivity to the action of proapoptotic signals still remain unexplored.