Do proteolytic enzymes affect the development of idiopathic pulmonary fibrosis.

<bold>Background:</bold> An important role in the development of idiopathic pulmonary fibrosis belongs to the destruction of proteins of the extracellular matrix (ECM) by proteolytic enzymes. <bold>Purpose:</bold> to investigate the indicators of blood trypsin-like activity (TPA) and fibronectin (FN) in patients with IPF. <bold>Methods:</bold> clinical data, spirography, FN serum, indicators of TPA (electrophoresis method), non-parametric statistics. <bold>Results:</bold> 34 patients with IPF were examined, average age 57.6±1.7 years, divided by the severity of the condition into subgroups I (moderate condition) and II (severe condition). Control group(CG) – 11 people, average age 50.8±3.8. The level of FN was increased - 374.4 ± 20.1 μg/ml versus 300.5 ± 22.0 μg/ml in CG (p<0.05). There were no differences between FN indicators in groups I and II (p> 0.05). Direct connections between the level of FN and severity of shortness of breath according to the mMRC scale were established - rs= +0.41; p<0.05, inverse – with FEV1/FJEL index – rs= −0.47; p<0.05. The median TPA in patients was 47.2 [29.1 – 58.6] IU/ml versus 32.2 [22.5 – 52.7] IU/ml in CG (p<0.05 according to the U-criterion). The level of TPA in group I and CG practically did not differ (p>0.05). There is a direct moderate correlation between the level of TPA and the severity of IPF – rs= +0.41 (p<0.05), the increase in the level of TPA in patients of subgroup II - 54.8 [34.7 – 78.1] IU/ml vs. 35.2 [20.6 – 45.6] IU/ml in patients of subgroup I (p<0.05 according to the U-criterion). <bold>Conclusion:</bold> activation of TPA contributes to the destruction of ECM with subsequent development of lung fibrosis.