EFFECT OF CORTICOSTEROID THERAPY ON FIBRINOLYSIS IN PATIENTS WITH INFLAMMATORY AND NON-INFLAMMATORY CONDITIONS

Overview of Fibrinolysis

The modern concepts of fibrinolytic activation and inhibition are discussed in this paper and the importance of the complex interlinkage with the kallikrein-kinin, coagulation, complement and immunity mechanisms is underlined.

The importance of the fibrinolytic balance as a protective mechanism in prevention of thrombus formation, in inflammation and in cancer is postulated and in population studies the normal decline with age is standardised.

The possibilities for long term fibrinolytic enhancement by use of a variety of drugs, such as the biguanides and anabolic steroids has been demonstrated.

Abnormal plasma fibrinolysis in patients with rheumatoid arthritis and impaired endothelial fibrinolytic response in those complicated by vasculitis

OBJECTIVES

(a) To assess plasma fibrinolytic parameters in patients with rheumatoid arthritis (RA) and to determine whether there are differences between patients with RA alone and those with RA complicated by vasculitis. (b) To determine if patients with RA respond differently to venous occlusion compared with normal subjects and to assess whether such a response differs in patients with RA alone and those with rheumatoid vasculitis. (c) To determine the extent of vascular damage in patients with rheumatoid vasculitis and if this correlates with the levels of plasma fibrinolytic parameters.

METHODS

Sixty three patients with RA (38 had RA only and 25 had evidence of rheumatoid vasculitis) were recruited. Plasma levels of tissue plasminogen activator antigen (t-PA Ag), plasminogen activator inhibitor (PAI) activity, and factor VIII von Willebrand factor (vWF) were measured before and 10 minutes after venous occlusion.

RESULTS

Patients with RA, with or without rheumatoid vasculitis, had higher baseline PAI levels than control subjects. The difference was statistically significant for patients with RA alone but was not statistically significant for patients with rheumatoid vasculitis. After venous occlusion, t-PA Ag levels increased significantly in normal subjects and patients with RA alone, but not in patients with rheumatoid vasculitis. Plasma levels of vWF were significantly higher in patients with rheumatoid vasculitis than in normal subjects and those with RA alone. In patients with RA alone, baseline vWF correlated positively with t-PA Ag levels, whereas a negative correlation was found between these two parameters in patients with rheumatoid vasculitis. A negative correlation between vWF and t-PA Ag levels after venous occlusion was also found in patients with rheumatoid vasculitis.

CONCLUSIONS

Patients with rheumatoid vasculitis showed evidence of vascular damage with increased levels of vWF and impaired t-PA Ag release after venous occlusion, a useful measurement of endothelial reserve to remove fibrin. This may be of pathophysiological importance in the development of vasculitis in these patients.

Defective release of tissue plasminogen activator in systemic and cutaneous vasculitis

The fibrinolytic system in a group of 23 patients with vasculitis and 10 patients with the cutaneous vasculitis atrophie blanche were studied. These patients were found to have markedly suppressed release of vascular tissue plasminogen activator (t-PA) stores whether the disease was active or in remission. The control group had releasable t-PA levels of 0.70 +/- 0.10 IU/ml of plasma. Levels of releasable t-PA in the patient population were 0.09 +/- 0.03 IU/ml for those with active vasculitis (p less than 0.0001 compared with the control group by the Student t test), 0.23 +/- 0.12 IU/ml for those with inactive vasculitis (p less than 0.001), and 0.03 +/- 0.01 IU/ml for those with atrophie blanche (p less than 0.0001). It is concluded that there is a generalized defect in plasminogen activator in a variety of vasculitides. Such a defect may contribute to the pathogenesis of lesions as well as the thromboembolic disease that may be observed in these patients.

Thrombosis (infarction) induced by kappa-carrageenin in rat tail: inhibition during adjuvant arthritis

Thrombosis (infarction) frequency of rat tail after i.v. injection of kappa-carrageenin was significantly reduced during primary phase of adjuvant arthritis. In healthy rats thrombosis was not influenced by injection of soybean trypsin inhibitor or by strong local irritation after i.p. injection of lambda-carrageenin. Inhibition of thrombosis during adjuvant arthritis occurs contrary to the expectation because fibrinogen concentration and platelets count are increased and fibrinolysis is decreased during arthritis. Reduced thrombosis frequency in adjuvant arthritis might be due to inhibition of clotting processes and/or increased vasodilation.

The fibrinolytic system in man

The existence of a system in the human body capable of inducing the dissolution of endogenous pathologically formed thrombi was appreciated in ancient times. Considered in detail in this article are the data that have elucidated the physiologic regulation of which plasmin formation is dependent on, the plasma concentration of plasminogen, availability of activators of plasminogen in the plasma and surrounding tissue environment, the concentration of naturally present inhibitors, and the existence of fibrin in the circulation. Important in this rapidly progressive scientific discipline is consideration of the factors which control the synthesis of the components of this proteolytic enzyme system. Recently abundant information has indicated that this plasminogen-plasmin proteolytic enzyme system can be utilized therapeutically. Knowledge of the mechanisms of this system has permitted identification of agents that can be exogenously administered to releave thrombotic obstruction to blood flow in the venous (pulmonary emboli, deep vein thrombosis) and arterial (peripheral and central vessels) circulatory systems. Particularly important is the demonstration that thrombolytic agents can directly attack and alleviate the immediate cause of acute myocardial infarction. As a result of the innovations in the present decade, it is evident that the plasminogen system can be advantageously employed to reverse the pathologic effects of all thrombotic diseases.

Coagulation abnormalities in rheumatoid disease

Forty-one patients with rheumatoid arthritis, including 6 with acute vasculitis, 13 with chronic vasculitis, and 22 without vasculitis, were studied for evidence of intravascular coagulation and fibrinolysis (ICF). The mean plasma fibrinogen levels were elevated in all groups. The fibrinogen, platelet count, and fibrin split products were usually elevated in acute vasculitis. Fewer patients on corticosteroids had abnormal coagulation tests. Active plasmin was detected in 12 patients primarily with chronic vasculitis. Plasminogen activator activity was not diminished in vascular endothelium of normal appearing skin of those patients with or without vasculitis. None of the patients demonstrated decompensated intravascular coagulation and fibrinolysis. The results suggest overcompensated ICF occurring in rheumatoid arthritis, but rheumatoid patients with vasculitis cannot be clearly distinguished from those without vasculitis on the basis of the usual tests performed for coagulation and fibrinolysis abnormalities.

A comparative analysis of warfarin and low-dose heparin as thromboembolism prophylaxis in total hip replacement patinets

Warfarin, low-dose heparin, or a combination of low-dose heparin and hydrocortisone was administered to 300 patients undergoing total hip replacement. The lowest incidence of thromboembolic (5 per cent) was attained with Warfarin. Further investigation into the method of administration of low-dose heparin is necessary before it can be used effectively as thromboembolism prophylaxis in total hip replacement patients. The addition of hydrocortisone was not found useful.

Components of the fibrinolytic system in synovial joints. Normal bovine compared with normal and abnormal human synovial joints

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