Matrix metalloproteinase‐2, ‐7, and ‐9 activities in dogs with idiopathic pulmonary fibrosis compared to healthy dogs and dogs with other respiratory diseases

Abstract Background Canine idiopathic pulmonary fibrosis (CIPF) is a chronic, interstitial lung disease that mainly affects West Highland white terriers (WHWTs) and is characterized by excessive deposition of extracellular matrix (ECM) in the lung. Matrix metalloproteinases (MMPs) participate in remodeling of ECM. Objectives To compare metalloproteinase‐2, ‐7 and ‐9 activities in blood or bronchoalveolar lavage fluid (BALF) samples or both of CIPF WHWTs with healthy WHWTs, healthy dogs of other breeds, and dogs with other lung diseases and determine if these MMPs could be used as diagnostic and prognostic markers for CIPF. Animals Forty‐four CIPF WHWTs, 24 dogs with chronic bronchitis (CB), 17 with eosinophilic bronchopneumopathy (EBP), 10 with bacterial pneumonia, 39 healthy WHWTs, and 35 healthy dogs of other breeds. Methods Cross‐sectional observational study. Pro‐MMP and active MMP activities were analyzed by zymography. Results In serum, significantly higher (P < .01) pro‐MMP‐7 activities were observed in CIPF WHWTs compared to healthy dogs of other breeds, dogs with CB and dogs with EBP. In BALF of CIPF WHWTs, both pro‐MMP‐9 and pro‐MMP‐2 activities were significantly higher (P < .01) compared to healthy WHWTs, but these differences were not detected in plasma. The CIPF WHWTs had significantly higher (P < .05) activities of pro‐MMP‐9 compared to dogs with CB and of pro‐MMP‐2 compared to dogs with CB and EBP. No statistically significant prognostic factors were observed in CIPF WHWTs. Conclusions and clinical relevance Serum MMP‐7 and BALF MMP‐2 and ‐9 potentially may be useful diagnostic markers but not prognostic markers for CIPF.