MMP13 and chronic obstructive pulmonary disease: Additional collagenases may exert a major role in lung homeostasis, possibly MMP-8 and MMP-13, which are also found to be induced in chronic obstructive pulmonary disease (Woode et al., 2015), or MMP-1, which is absent in fibroblast foci from idiopathic pulmonary fibrosis (Pardo and Selman, 2012).