To detect the levels of matrix metalloprotease (MMP)-1 and MMP-7 in the serum and the bronchoalveolar lavage fluid (BALF) of patients with idiopathic pulmonary fibrosis (IPF) and sarcoidosis (Stage II), and therefore to investigate the significance of these changes in the pathogenesis of IPF.
Forty-four clinically confirmed cases of IPF were recruited, with the patients' age ranging from 46 to 70 years (58 ± 9 years). Twenty patients with sarcoidosis, aged 35 to 65 (50 ± 12) years, were also studied. Enzyme-linked immunoabsorbent assay was used to detect the levels of MMP-1 and MMP-7 in the serum and the BALF samples.
In the serum of patients with IPF, the level of MMP-1 [3.78 (0.14 - 13.44) µg/L] was lower than that in patients with sarcoidosis [7.79 (4.67 - 10.68) µg/L (z = -3.53, P < 0.01)], but the level of MMP-7 [7.83 (3.57 - 14.37) µg/L] was higher than that in patients with sarcoidosis [4.04 (0.06 - 9.94) µg/L (z = -3.84, P < 0.01)]. In the BALF of patients with IPF, the level of MMP-1 [1.09 (0.04 - 5.14) µg/L] was lower than that in patients with sarcoidosis [2.08 (0.05 - 4.16) µg/L (z = -1.53, P > 0.05)], but the level of MMP-7 [3.75 (1.10 - 9.87)µg/L] was higher than that in patients with sarcoidosis [1.16 (0.02 - 4.47) µg/L (z = -5.33, P < 0.01)]. The serum level of MMP-7 in patients with IPF was negatively correlated with the diffusing capacity of carbon monoxide(r = -0.56, P < 0.01) and the percentage of neutrophils (r = -0.47, P < 0.01). The level of MMP-7 in the BALF showed a negative correlation with diffusing capacity of carbon monoxide (r = -0.31, P < 0.05).
The results suggest that MMP-1 may be increased in the inflammatory phase as compared to the matrix remodeling phase of lung fibrosis, while MMP-7 may be increased in the matrix remodeling phase rather than in the inflammatory phase. MMP-7 may act as an important indicator for the severity of IPF.