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 TAFI 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 TAFI 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 TAFI levels were significantly lower in both UC patients (14.7+/-3.1 microg/ml) and CD patients (13.3+/-3.4 microg/ml) compared with healthy controls (17.4+/-3.0 microg/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 TAFI levels and disease activity was also found. Plasma TAFI levels were significantly lower in patients with ileal CD compared with patients with colonic CD.

Conclusions: PAI-1 plasma levels are increased whereas TAFI levels are decreased in IBD patients. These results suggest an imbalance of fibrinolysis in IBD.