Plasma von Willebrand factor, tissue plasminogen activator, plasminogen activator inhibitor, and antithrombin III levels in Behçet's disease

Coagulation parameters and plasma total homocysteine levels in Behcet's disease

Behcet's disease (BD) is a multisystemic inflammatory disorder of unknown etiology that is sometimes associated with thrombosis in addition to systemic manifestations. However, the mechanism of hypercoagulability is not known. We evaluated the coagulation and fibrinolytic activities and the plasma total homocysteine levels of Korean BD patients in two cross-sectional studies. In the first study regarding coagulation and fibrinolytic activities, the levels of fibrinogen and von Willebrand factor (vWF) antigen were significantly higher in the BD patients than in the healthy controls (387.7+/-24.3 versus 240.6+/-8.8 mg/dl, p<0.001, and 131.9+/-8.8 versus 105.2+/-0.3%, p<0.01, respectively). The level of antithrombin III (AT III) was significantly lower in the BD patients (92.8+/-3.2 versus 106.3+/-2.6%, p<0.005). No differences were observed in the levels of plasminogen, protein C, or protein S activities. Activated protein C (APC) resistance was not observed in any BD patients. In the second study, the plasma total homocysteine levels of patients with a history of thrombosis (11.9+/-3.0 micromol/l) or disease activity (12.5+/-3.8 micromol/l) were found to be significantly higher than those of the controls (9.2+/-2.6 micromol/l, p<0.05, both). The plasma homocysteine concentrations in the thrombosis patients were positively correlated with plasma vWF levels; a relationship which suggests injury of the vascular endothelium (Spearman coefficient=0.857, p<0.01). Therefore, coagulation abnormality did not contribute to thrombotic complications, and higher levels of homocysteine may play a role in the hypercoagulablity of BD patients.

Pathological haemostasis and "prothrombotic state" in Behçet's disease

Behçet's disease (BD) is a widespread occlusive-type vasculitis with life-threatening manifestations. The vasculopathy of BD is unique and any type of vessel can be involved. Moreover, vascular lesions in BD represent an occlusive nature suggesting a hypercoagulable/prothrombotic state. The data concerning the genetic defects of the coagulation cascade are expanding. There is evidence of universal activation of haemostatic system in BD. Procoagulant markers of thrombosis are elevated reflecting intravenous excessive thrombin formation. Defective fibrinolysis with impaired fibrinolytic kinetics may have a role in the hypercoagulable/prothrombotic state of BD. Endothelial cell injury and/or pathological activation is well documented in BD. The aim of this paper is to review current literature knowledge and our experience regarding the unresolved complicated issues of genetic thrombotic defects, in vivo haemostatic markers, coagulation inhibitors, impaired fibrinolysis, and endothelial injury/dysfunction of the hypercoagulable/prothrombotic state of BD. The clinical aspects of vascular thrombosis, the genetic basis of coagulation, coagulation inhibitors, fibrinolysis inhibitors, and endothelial dysfunction are reviewed. Challenges and future prospects regarding the prothrombotic state of BD are discussed together with new promising antithrombotic and antiplatelet treatment strategies. Better understanding of the exact pathogenesis of the hypercoagulable/prothrombotic state of this disease may help to develop novel therapeutic approaches offering a better outcome for Behçet's patients with thrombosis.

Vascular involvement in Behçet's disease: relation with thrombophilic factors, coagulation activation, and thrombomodulin

PURPOSE

Thrombosis, usually venous, occurs in 10% to 25% of patients with Behçet's disease, but its pathogenesis is poorly understood. We evaluated parameters of hemostasis and their relation with thrombosis in a series of patients with Behçet's disease.

SUBJECTS AND METHODS

We studied 38 patients with Behçet's disease (13 with venous thrombosis), 38 patients with venous thrombosis without thrombophilia, and 100 control subjects. Levels or presence of protein C, protein S, antithrombin, methylenetetrahydrofolate reductase C677T, factor V Leiden, prothrombin gene G20210A, antiphospholipid antibodies, plasminogen, tissue-type plasminogen activator (tPA), type-1 tPA inhibitor (PAI-1), PAI-1 4G/5G polymorphism, prothrombin fragment 1+2, plasmin/alpha(2)-antiplasmin complexes, thrombomodulin, and activated factors VII and XII were determined.

RESULTS

There were no deficiencies in protein C, protein S, antithrombin, or factor V Leiden in the patients with Behçet's disease, nor was there evidence of most other thrombotic abnormalities. Compared with control subjects, however, the Behçet's disease group had elevated mean (+/- SD) levels of prothrombin fragment 1+2 (2091 +/- 1323 pmol/L vs. 804 +/- 398 pmol/L, P <0.001), plasmin/alpha2-antiplasmin complexes (410 +/- 220 microg/L vs. 214 +/- 92 microg/L, P <0.001), and thrombomodulin (37 +/- 24 ng/mL vs. 27 +/- 10 ng/mL, P <0.001). These levels did not differ between patients with or without thrombosis.

CONCLUSIONS

Thrombophilic factors do not seem to explain most thromboses in Behçet's disease. There is increased thrombin generation, fibrinolysis, and thrombomodulin in Behçet's disease, but these abnormalities are not related to thrombosis.

Increased levels of tissue factor pathway inhibitor may reflect disease activity and play a role in thrombotic tendency in Behçet's disease

Tissue factor pathway inhibitor (TFPI) is a Kunitz-type proteinase inhibitor that has a crucial role in haemostasis and is primarily synthesized in the vascular endothelium. We investigated plasma total TFPI, antiphospholipid antibodies, and some other coagulation and fibrinolytic system parameters in 30 patients with Behçet's disease and 15 controls by the enzyme-linked immunosorbent assay method. TFPI levels were significantly higher in the Behçet's group (119 +/- 57.5 ng/ml) compared with the control group (74.8 +/- 31.5) (P < 0.009). We also noted a statistical significance in TFPI levels between patients with active disease (n:16) (139 +/- 55) and patients without activation (n:14) (96 +/- 53) (P < 0.03), whereas inactive patients lacked any significance when compared with the control group (P < 0.29). Other parameters disclosed no statistical significance between patients and control group except for elevated fibrinogen and plasminogen activator inhibitor-1 levels in the patient group (P < 0.003). Increased levels of TFPI may reflect a defensive mechanism like in other diseases characterized by thrombotic tendency and represent a parameter of disease activity.

Vascular endothelial function and oxidative stress mechanisms in patients with Behçet's syndrome

OBJECTIVES

We sought to test the hypothesis that vascular endothelial function is impaired in Behçet's syndrome and reflects increased levels of oxidative stress.

BACKGROUND

Behçet's syndrome is a multisystem inflammatory disorder commonly complicated by vascular thrombosis and arterial aneurysm formation. The precise mechanisms underlying vascular disease in Behçet's syndrome are not known.

METHODS

We studied 19 patients with Behçet's syndrome (18 to 50 years old, 9 men) and 21 healthy volunteers (18 to 50 years old, 10 men). Brachial artery flow-mediated dilation (endothelium-dependent), and nitroglycerin (NTG)-induced dilation (endothelium-independent) were measured. To investigate oxidative stress mechanisms, vascular studies were repeated 1 h after administration of vitamin C (1 g, intravenous) in 12 patients and 12 control subjects.

RESULTS

Flow-mediated dilation was reduced in patients with Behcet's syndrome as compared with control subjects (0.7 +/- 0.9% vs. 5.7 +/- 0.9%, p = 0.001). In contrast, there were no significant differences in the brachial artery diameter (4.2 +/- 0.2 vs. 4.0 +/- 0.2 mm, p = 0.47) or NTG-induced dilation (19.7 +/- 1.9% vs. 19.7 +/- 1.2%, p = 0.98). In regression analysis, Behçet's syndrome was associated with impaired flow-mediated dilation independent of age, gender, brachial artery diameter, blood pressure, cholesterol and glucose. Vitamin C increased flow-mediated dilation in Behçet's syndrome (0.2 +/- 0.7% to 3.5 +/- 1.0%, p = 0.002), but not in control subjects (4.3 +/- 0.6% to 4.7 +/- 0.4%, p = 0.51). In both groups, NTG-induced dilation and brachial artery diameter were unchanged after vitamin C treatment.

CONCLUSIONS

Vascular endothelial function is impaired in Behcet's syndrome and can be rapidly improved by vitamin C treatment. Our results support a role for oxidative stress in the pathophysiology of Behçet's syndrome and provide a rationale for therapeutic studies aimed at reducing vascular complications in this disorder.