Elevated MMP2 expression in fibrotic interstitial lung disease: a potential biomarker for assessment of disease severity

This study was implemented to reveal the expression and the clinical correlation of matrix metalloproteinase 2 (MMP2) in patients with interstitial lung disease ILD. This clinical study was conducted with 72 subjects (37 males, 35 females; mean age: 61.18(±13.95)years). They were divided into fibrotic group and non-fibrotic group based on whether the images showed fibrotic ILD. MMP2 concentrations in patients’ serum and bronchoalveolar lavage fluid balf were detected by enzyme-linked immunosorbent assay. Immunofluorescence staining was used to assess spatial expression of MMP2 and denatured collagen in fibrotic lung tissues. Serum and alveolar lavage fluid concentrations of MMP2 were significantly higher in the fibrosis group than in the non-fibrosis group. MMP2 level in serum was negatively correlated with forced expiratory volume in the first second (FEV1), total lung volume (TLC), residual volume (RV), and lung diffusing capacity for carbon monoxide (DLCO). Pearson statistical analysis revealed that MMP2 expression was positively related to leucocyte, carbohydrate antigen125 (CA125) and carcinoembryonic antigen(CEA). Fluorescently labeled collagen hybridizing peptide CHP was used to specifically localize degenerative collagen in the lung tissues of five lung transplantation patients, immunofluorescence results showed that MMP2 and CHP were co-localized and highly expressed in fibrosis tissue. Expressions of MMP2 is significantly increased in patients with fibrotic interstitial lung disease. Higher expression of MMP2 implies more severe impairment of lung function, suggests that MMP2 could be used as potential biomarker for assessing severity of ILD.