Pia Glas-Greenwalt

Enhancing effect of dietary supplementation with ω-3 fatty acids on plasma fibrinolysis in normal subjects

A supplement of MaxEPA oil containing 5 g of omega-3 polyunsaturated fatty acids was given for two weeks to nine normal volunteers. The vascular plasminogen activator (VPA) level increased and there was a fall in the levels of inhibitors of vascular plasminogen activator (IPA) and of plasmin, alpha 2-antiplasmin (alpha 2-AP). No significant changes occur in serum cholesterol, triglycerides, HDL or LDL levels.

Activation of fibrinolysis by apolipoproteins of high density lipoproteins in man.

The effects on fibrinolysis of purified normal human plasma lipoproteins and their apolipoproteins (apo) were assessed in an in vitro system containing urokinase, plasminogen, and fibrin. High and very low density lipoproteins (HDL and VLDL, respectively) but not low density lipoproteins (LDL) significantly increased lysis of radiolabeled fibrin or lysis area of plated fibrin compared to controls. Apo HDL, apo HDL2, apo HDL3, apo VLDL (buffer soluble apo), apo AI and AII activated fibrinolysis by 1.3-1.4 fold of control values, whereas apo B (as a narrow density cut of LDL) and non-lipoprotein control proteins (albumin and myoglobin) did not. Addition of HDL in the absence of urokinase failed to activate fibrin lysis. These data demonstrate that the major proteins of HDL - apo AI and apo AII - and possibly certain minor constituent(s) common to HDL and VLDL participate in the fibrinolytic process.

Use of ancrod in acute or progressing ischemic cerebral infarction

Ancrod has been used in Europe for over 15 years for peripheral vascular disease, deep vein thrombosis, and central retinal venous thrombosis, and in patients at risk for thromboembolism. In a double-blind, randomized, placebo-controlled study at University Hospitals in Cincinnati, 20 acute cerebral infarction patients received a series of IV infusions of ancrod (ten) or placebo (ten) for seven days. Early fibrinolysis with a small decrease in fibrinogen was observed, and d-dimers were elevated at four hours, indicating early clot lysis. At three months, patients with moderate to severe strokes (less than 40 on the Scandinavian Stroke Scale) in the ancrod group showed average improvement by a factor of 3 over the placebo group. No bleeding, abnormal laboratory results, or deaths occurred, but ancrod was discontinued in one patient who had seizures. As a result of this study, a double-blind multicenter international clinical trial to further assess the safety and effectiveness of ancrod is being planned.

Ancrod Causes Rapid Thrombolysis in Patients with Acute Stroke

Clot lysis is desirable in patients with thrombi in arteries and arterioles by a safe rapidly-acting thrombolytic agent. Ancrod cleaves fibrinogen; the resulting circulating ancrod-fibrin stimulates fibrinolysis. Ancrod action and effect were studied in 20 patients with acute developing stroke in a double-blind, placebo-controlled study. Patients were randomly assigned to one of two treatment groups, and received either normal saline or ancrod 0.5 mu/kg in normal saline administered as a constant-rate intravenous infusion over 6 hours. Subsequent doses of ancrod (or saline placebo) were determined daily thereafter for a total treatment period of 7 days. Neither bleeding nor re-thrombosis occurred within the 90 day follow-up period. That ancrod acted rapidly was shown by a significant decrease in functional plasminogen activator inhibitor (PA-I) within 60 minutes, and by significant elevations of fibrin(ogen) degradation products (FDP) and D-dimer within 3 and 4 hours. The biological effect of fibrinolysis in ancrod infused patients was demonstrated by a greater improvement in stroke score when compared to those infused with saline.

Postoperative venous thromboembolism and brain tumors: part II. Hemostatic profile

Preoperative hemostatic data were obtained on 42 brain tumor patients and correlated with the subsequent occurrence of venous thrombosis detected with 1211-labeled fibrinogen leg scans. The occurrence of thrombosis correlated significantly with an increased prothrombin time, plasminogen, and total fibrinolytic activity and a decreased fibrinogen level. This overall trend in the group of patients with postoperative thrombosis indicates that the hemostatic disorder noted in brain tumor patients is most closely related to a subclinical form of chronic disseminated intravascular coagulation syndrome.Differences in hemostatic parameters seen with the various types of brain tumors suggest that biological factors specific to each tumor are likely responsible for the described hemostatic disorder and support the need for further research directed at the tumor tissue level.

Fish oil has beneficial effects on lipids and renal disease of nephrotic rats

The effects of fish oil on serum lipids, eicosanoid production, fibrinolysis, and renal disease of nephrotic rats were studied. Three groups of rats were given adriamycin to induce nephrotic syndrome. They were pair-fed diets containing 14% beef fat, 3%, and 14% fish oil, and killed at 4 weeks. Marked beneficial effects of the fish oil on plasma triglycerides, total cholesterol, and LDL cholesterol were observed. Fish oil suppressed dienoic eicosanoid production. Protection of renal function and morphology was achieved in the fish oil fed groups, as evidenced by lower serum creatinine levels and lesser degrees of tubular dilatation and intraluminal protein in the kidney tubules. We conclude that fish oil, rich in n-3 fatty acids, is beneficial to the plasma lipids and may prevent progression of renal disease in this model of nephrotic syndrome. These two events may be interrelated.

Deficiency of a plasma factor stimulating vascular prostacyclin generation in patients with lupus nephritis and glomerular thrombi and its correction by ancrod: In-vivo and in-vitro observations

Glomerular thrombi occur frequently in active lupus nephritis. Their presence has been correlated with low platelet counts and with subsequent development of glomerular sclerosis. We have examined the plasma PGI2 generating capacity of 8 patients with active lupus nephritis with thrombi that were to undergo defibrination therapy with ancrod. PGI2 generation by these plasma samples was significantly decreased as compared both to normals and to 6 individuals with lupus nephritis and no glomerular thrombi. Significant improvement in the capacity to generate PGI2 was seen in the post-ancrod treatment plasma samples. the pathogenesis of this defect is discussed.

Ancrod decreases the frequency of cyclic flow variations and causes thrombolysis following acute coronary thrombosis

The potential use of ancrod, a purified isolate from the venom of the Malaysian pit viper, Agkistrodon rhodostoma, in decreasing the frequency of cyclic flow variations in severely stenosed canine coronary arteries and causing thrombolysis of an acute coronary thrombus induced by a copper coil was evaluated. Open-chest, anesthetized dogs were used. Ancrod was given intravenously (8 U/kg) over 1 hour and caused a significant reduction in the frequency of cyclic flow variations (5.8 +/- 0.7 to 3.6 +/- 0.8 cyclic flow variations per 30 minutes, p less than 0.05), whereas control animals failed to decrease the frequency of their cyclic flow variations over the same time period (5.3 +/- 0.3 to 5.0 +/- 0.4 cyclic flow variations per 30-minute period). Twenty-seven dogs had a coronary thrombus induced by a copper coil positioned directly in a major coronary artery; of these, four died of ventricular fibrillation prior to treatment, eight received an infusion of saline and showed no thrombolysis over 5 hours, and three died of ventricular fibrillation during the initial part of an intravenous infusion of ancrod. The remaining 12 dogs received ancrod intravenously (16 U/kg); six demonstrated lysis of the coronary thrombus (mean time to lysis, 65 +/- 20 minutes). The concentrations of ancrod used in these studies produced a severe decrease in systemic fibrinogen concentration and a significant decrease in the inhibitor of plasminogen activator levels. Thus, ancrod decreases the frequency of cyclic flow variations in stenosed canine coronary arteries and may cause coronary thrombolysis in approximately 50% of animals within 65 +/- 20 minutes of its intravenous administration.