MMP1 and idiopathic pulmonary fibrosis: Interestingly, MMP1, MMP7, CCL2, CXCL1, IGFBP-2, and PAI-1 are secreted factors that have been found to be increased in patients with progressive fibrosis, as well as to be secreted by cells with evident SASP, suggesting a close mechanistic connection between IPF and cellular senescence [50,51,54] (Figure 2).