Matrix metalloproteinase-7 is increased in lung bases but not apices in idiopathic pulmonary fibrosis.

Our cross-sectional study suggests that lung epithelial MMP7 expression increases as the tissue becomes more fibrotic and identifies a potentially nonepithelial or immune-cell source. Mechanisms of disease progression in IPF are still unclear, and our study suggests aberrant MMP7 production may be a histological starting point of lung tissue fibrosis.