TNF and idiopathic pulmonary fibrosis: Comeglio et al. confirmed that OCA could considerably reduce the production of proinflammatory cytokines (i.e., IL-1β, IL-6, and TNF-α) in the IPF rat model and could also regulate the proportion of matrix metalloproteinases (MMP) and their inhibitors (tissue inhibitor of metalloproteinases, TIMP), thereby alleviating the symptoms of pulmonary fibrosis.