Plasma thrombin-activatable fibrinolysis inhibitor and plasminogen activator inhibitor-1 levels in inflammatory bowel disease

Background Patients with inflammatory bowel disease (IBD) have an increased risk of thromboembolic events. Imbalance of fibrinolysis has been suggested as one of the possible pathogenetic mechanisms. As plasminogen activator inhibitor-1 (PAI-1) and thrombin-activatable fibrinolysis inhibitor (TAFI) are inhibitors of fibrinolysis, we studied TAR as well as PAI-1 plasma levels in IBD patients compared with healthy controls. Methods A total of 132 IBD patients [68 ulcerative colitis (UC) and 64 Crohn's disease (CD)] and 50 healthy controls were enrolled. PAI-1 and TAR plasma levels were assessed by commercially available enzyme-linked immunosorbent assay kits. Their relationship with clinical parameters of UC and CD was assessed. Results Mean plasma PAI-1 levels were significantly higher in both UC patients (3.9 +/- 1.3 IU/ml) and CD patients (4.0 +/- 1.5 IU/ml) compared with healthy controls (3.1 +/- 1.1 IU/ml) (P=0.01). On the other hand, mean plasma TAR levels were significantly lower in both UC patients (14.7 +/- 3.1 mu g/ml) and CD patients (13.3 +/- 3.4 mu g/ml) compared with healthy controls (17.4 +/- 3.0 mu g/ml) (P < 0.0001). Patients with active disease had significantly higher PAI-1 levels compared with patients with inactive disease for both diseases (P=0.03 and P=0.01, respectively). No significant association between plasma TAR levels and disease activity was also found. Plasma TAR levels were significantly lower in patients with ileal CD compared with patients with colonic CD. Conclusion PAI-1 plasma levels are increased whereas TAR levels are decreased in IBD patients. These results suggest an imbalance of fibrinolysis in IBD.