Effect of polymyxin B-immobilized fiber on blood metalloproteinase-9 and tissue inhibitor of metalloproteinase-1 levels in acute respiratory distress syndrome patients

BACKGROUND/AIMS: Metalloproteinase (MMP)-9 plays a role in the pathogenesis of acute respiratory distress syndrome (ARDS). Polymyxin B-immobilized fiber (PMX-F) treatment improves circulatory disturbance and oxygenation in ARDS patients. We aimed to assess whether PMX-F treatment alters the blood MMP-9 and tissue inhibitor of MMP (TIMP)-1 levels in ARDS patients. METHODS: Twelve ARDS patients who received PMX-F treatment and 20 healthy control volunteers were included in this study. PMX-F was carried out twice at a rate of 100 ml/min for 2 h with a time interval of 24 h. Blood MMP-9 and TIMP-1 levels were measured before and after PMX-F treatment. We monitored blood pressure and the PaO2/FiO2 (PF) ratio before and after PMX-F treatment. RESULTS: The mortality of ARDS patients after PMX-F treatment was 16.7%. Chest X-ray abnormalities were ameliorated in surviving patients after PMX-F treatment. Systolic and diastolic blood pressure increased significantly after PMX-F treatment (p < 0.01). The PF ratio also increased significantly after PMX-F treatment (p < 0.01). Blood MMP-9 and TIMP-1 levels in ARDS patients (126.4 +/- 36.4 and 326.5 +/- 52.5 ng/ml) were significantly higher than in controls (34.5 +/- 12.5 and 160.5 +/- 24.5 ng/ml; p < 0.01). PMX-F treatment reduced these levels significantly (the first treatment: MMP-9 85.4 +/- 28.6 ng/ml, p < 0.05, TIMP-1 265.8 +/- 36.6 ng/ml, p < 0.05; the second treatment: MMP-9 56.5 +/- 18.8 ng/ml, p < 0.01, TIMP-1 220.6 +/- 30.5 ng/ml, p < 0.01). CONCLUSION: These data suggest that MMP-9 and TIMP-1 may play a role in the pathogenesis of ARDS and that PMX-F treatment ameliorated increased MMP-9 and TIMP-1 levels in ARDS patients.