Amount Of Fibrin Degradation Products Research Articles

Assessing Safety of Thrombolytic Therapy.

Thrombolytic therapy involves thrombolytic agents administered to patients suffering from venous or arterial thrombosis. The therapy induces systemic effects interrelated with the thrombolytic agent used. Bleeding is a prominent complication of thrombolytic therapy. Exhaustion of coagulation factors, generation of excessive amounts of fibrin degradation products (FDPs), therapy-induced activation of coagulation, therapy-induced anticoagulation, and formation of new fibrin all illustrate the complexity of effects of the treatment and challenges the hemostatic balance in the patients. The therapy-induced effects can be modulated by parallel administration of anticoagulants. Risk assessment is mandatory prior to thrombolytic therapy. Anticoagulated and unconscious patients represent particular safety concerns, and should be fully evaluated. Several guidelines describe the choice of tests and their safety limits in relation to pretreatment evaluation of anticoagulated patients. Fibrinogen depletion and FDPs during treatment may be promising markers for the evaluation of bleeding risk posttreatment. Future risk assessment measures should focus on the dynamics of the hemostatic balance. Here, thromboelastography may be considered a tool addressing clot formation, fibrin structure, and fibrinolytic resistance in parallel. Suitable laboratory analysis performed shortly after treatment may help to recognize severe treatment-induced systemic effects that can be counteracted by rational treatment, thereby reducing bleeding risk.

Abstract 415: Oxidized High-Density Lipoprotein Reduces Blood Clot Firmness

Low high-density lipoprotein (HDL) levels are a risk factor for cardiovascular disease. The best established anti-atherogenic property of HDL is its role in reverse cholesterol transport. Unlike HDL, low-density lipoprotein (LDL) has atherogenic properties and these are enhanced when LDL is oxidatively modified. Oxidized lipids can be transferred from oxidized LDL (oxLDL) to HDL and then be transported to the liver. However, other properties of circulating oxidized HDL (oxHDL) are not extensively investigated. Therefore we studied the role of native HDL (nHDL) and oxHDL in hemostasis. We collected citrated blood from healthy volunteers (n=5) and examined the effects of 4 mg/ml added nHDL and oxHDL on tissue factor-induced clot formation and clot firmness using thromboelastography (ROTEM). The effects of nLDL and oxLDL were measured as a control. Lipoproteins were isolated from plasma with density-gradient ultracentrifugation and oxidized with copper sulphate. The effect on fibrin degradation was examined by thromboelastography in the presence of cytochalasin D (2.5 μg/ml) and by measuring fibrin degradation products in the serum after thromboelastography using an ELISA. The ROTEM parameters clotting time, clot formation time and α-angle, were not affected by the addition of nHDL or oxHDL. The clot firmness, measured as amplitude, reduced during the thromboelastography by the addition of oxHDL. The amplitude (±SD) at 30 minutes, at 45 minutes, and at 60 minutes decreased from 100 (±0)%, 96 (±1.8)% and 91 (±2.9)% to 63 (±24.8)%, 51 (±24.3)% and 45 (±23.5)%, respectively (p<0.05) by the addition of oxHDL but did not change by the addition of nHDL. Fibrin breakdown, as measured by clot firmness in the presence of cytochalasin D was not affected by added oxHDL. In addition, the amount of fibrin degradation products after thromboelastography was comparable between control blood and blood with added oxHDL. No effects on clot firmness were observed with nLDL and oxLDL. In conclusion, oxHDL, but not nHDL, reduces blood clot firmness in a time-dependent manner without interfering with the clot formation. This effect does not reflect fibrinolysis but most likely involves platelets. The precise mechanism by which oxHDL reduces clot firmness has yet to be elucidated.

Ovarian Carcinoma: Clinical Validity by Simultaneous Determination of Fibrin Degradation Products with the DR-70™ Immunoassay and CA-125

Fragestellung: Tumorzellen weisen häufig einen hohen Gehalt an Proteasen auf, die entscheidend an der Fibrinolyse beteiligt sind. Der DR-70™-Immunoassay misst mit hoher Spezifität Degradationsprodukte des Fibrins. Dieser Test ist, wenn auch an kleinen Fallzahlen, erfolgreich eingesetzt worden als Tumormarker zur Erfassung einer Reihe von Tumorentitäten. In der vorliegenden Arbeit wird dieser Test beim Ovarialkarzinom mit CA-125, dem „Goldstandard“ beim Ovarialkarzinom, verglichen. Methoden: Im Serum von 61 Patientinnen mit histologisch gesichertem Ovarialkarzinom, aber auch im Serum von 135 Patientinnen mit entzündlichen Erkrankungen bzw. anderen Malignomen bzw. benignen Tumorerkrankungen wurde die Aktivität von DR-70™ im Serum gemessen. Als Kontrollgruppe dienten 100 Blutspenderinnen, die als tumorfreie, gesunde Frauen eingestuft wurden. Der DR-70™ ist ein ELISA, der nach den Vorgaben des Herstellers (AMDL, Tustin, CA, USA) eingesetzt wurde. Ergebnisse: Als Mittelwert ± S. D. in der Kontrollgruppe wurde 0,41 ± 0,1 µg/ml für DR-70™ ermittelt. Im Vergleich dazu lag der Mittelwert der Serumproben von 61 Patientinnen mit Ovarialkarzinom bei 7,0 ± 10,5 µg/ml, bei einer Schwankungsbreite von 0,6 bis 58,5 µg/ml. Wird der Cut-off-Wert für DR-70™ auf > 1,2 µg/ml festgelegt, beträgt die Sensitivität des Testes 83,6 %, und der Wert für die Spezifität liegt bei 100 %. Verglichen mit CA-125 liegt die Sensitivität für DR-70™ 13,1 % höher. Schlussfolgerung: DR-70™ repräsentiert einen Tumormarker, der mit höherer Sensitivität und vergleichbarer Spezifität wie CA-125 Ovarialkarzinome zu diagnostizieren in der Lage ist.

Post-operative blood loss after transurethral prostatectomy is dependent on in situ fibrinolysis.

To evaluate whether post-operative blood loss in patients with benign prostatic hyperplasia, undergoing transurethral resection of the prostate (TURP), depends on in situ fibrinolysis in urine, and to determine the relative contributions of the urokinase and tissue-type plasminogen activator systems. TURP was performed in 24 men (median age 68.5 years, range 52-78) and the weight of resected tissue, the operative and post-operative blood loss determined. The concentrations of the urokinase- (u-PA) and tissue-type plasminogen activator (t-PA)-related fibrinolysis in their urine was followed using sensitive and specific assays, and the changes related to post-operative blood loss. Measurements of the urinary concentrations of free t-PA activity, t-PA antigen, free u-PA activity, u-PA antigen and fibrin degradation products (FbDP) were determined and the area under the curve for each of these quantities correlated with the post-operative blood loss. The post-operative blood loss correlated significantly with the per-operative loss (P = 0.047) and the weight of resected tissue (P = 0.029). There was a highly significant correlation between the area under the curve of FbDP in the urine and the post-operative blood loss (P < 0.005), while there was no significant positive correlation between the PA concentration or activity in the urine and post-operative blood loss. There was a significant correlation between the urinary t-PA activity and the amount of FbDP in the urine (P = 0.047), and a significant correlation between the weight of resected tissue and the amount of FbDP in the urine (P = 0.014). The post-operative blood loss after TURP is significantly related to an increase of the urinary fibrinolytic activity and the enhanced fibrinolytic activity is probably caused by t-PA.

Safety and therapeutic effectiveness of reinfused shed blood after open heart surgery

This prospective study was designed to determine whether use of nonwashed shed mediastinal blood exacerbated platelet and related hematologic dysfunctions after cardiopulmonary bypass, compared with the alternative use of autologous and homologous standard liquid preserved blood for volume support. Thirty-two patients undergoing cardiopulmonary bypass for open heart operations were randomized to receive either nonwashed shed mediastinal blood (group 1; n = 16) or liquid preserved packed red blood cells (group 2; n = 16) for transfusion therapy in the management of postoperative bleeding. Patient blood samples and bleeding times were obtained preoperatively, after cardiopulmonary bypass but before transfusions, 2 and 24 hours after transfusion, and on postoperative days 2, 3, and 7. Group 1 patients received an average of 710 ± 90 mL (range, 300 to 1,700 mL) of nonwashed shed mediastinal blood containing significantly greater ( p < 0.0001) amounts of fibrin degradation products and d-dimer protein. Of the hematologic, microaggregate, and plasma protein measurements performed, only the protein C level was significantly greater in group 1 ( p < 0.05) after transfusion. Patient bleeding times were not significantly different between the groups at any of the time points, and the total postoperative blood loss was not different between the groups. There was a trend toward less need for homologous transfusion m group 1 ( p < 0.1). This study documents the safety and ease of using nonwashed shed mediastinal blood as a primary blood volume support after an open heart operation.

Factors influencing the accumulation in fibrous plaques of lipid derived from low density lipoprotein: I. Relation between fibrin and immobilization of apo B-containing lipoprotein

The lipid that accumulates in some fibrous atherosclerotic lesions appears to be derived from plasma low density lipoprotein (LDL). An early stage in lipid accumulation may be immobilization of a fraction of the LDL, and this is released by incubation with proteolytic enzymes, of which the most effective is the fibrinolytic enzyme, plasmin. We have examined the relationship between release of fibrin degradation, products (FDP) and LDL in controlled plasmin incubations of 42 samples of normal intima and atherosclerotic lesions from aortas of 10 patients. In three patients (group 1) no LDL was released from any of the 11 tissue samples although they comprised lesions as well as normal intima. In 2 more patients (group 2) LDL was consistently low. However, in 5 patients (group 3) substantial amounts of LDL were released from all 21 tissue samples, and there was a significant correlation between the amounts of FDP and LDL ( P < 0.001). In spite of this correlation there were marked differences in the ratio FDP LDL , but analysis by SDS-polyacrylamide gel electrophoresis and immuno blotting of the FDP released showed no consistent pattern related to LDL binding. Although the ratio FDP LDL showed a 4-fold range, in 6 lesions subjected to successive 2-h incubations with plasmin the ratio within each lesion remained constant, supporting the concept that fibrin and LDL are linked.

Degradation products of fibrin and of fibrinogen in synovial fluid and in plasma of patients with rheumatoid arthritis

Degradation products of fibrin and of fibrinogen, together (FDP) and separately, were measured in plasma and synovial fluid of patients with rheumatoid arthritis using specific enzyme immunoassays. Considerable amounts of fibrin degradation products (fibrin-DP) were found in the synovial fluid; only 1 case yielded some fibrinogen-derived products (fibrinogen-DP). In plasma relatively small amounts of degradation products, both fibrin-DP and fibrinogen-DP, were present. From the discrepancy between the amount and composition of degradation products in synovial fluid and in plasma we conclude that there are extra-articular sites of fibrin(ogen) breakdown in rheumatoid arthritis. The new specific methods may contribute to the understanding of the role of fibrinolysis in rheumatoid disease and in inflammation in general.

Apparent coagulopathy caused by infusion of shed mediastinal blood and its prevention by washing of the infusate

We found that reinfusion of shed mediastinal blood (SMB) after a cardiac operation was associated with laboratory evidence of disseminated intravascular coagulation. In view of this, we compared the effect of infusing washed or unwashed SMB on the coagulation profiles and blood use of two serial groups of patients undergoing cardiopulmonary bypass. We found that the results of testing for fibrin degradation products converted from negative to positive in 17 of 20 patients who received unwashed SMB versus 1 of 14 patients who received washed SMB ( p < 0.0001). Other coagulation studies did not reveal disseminated intravascular coagulation in either group, nor were there differences in blood use between the two groups. The unwashed SMB contained high titers of fibrin degradation products (mean reciprocal titer = 354 ± 161) compared with washed SMB (mean reciprocal titer = 34 ± 18) ( p < 0.01). Based on the volume of SMB infused, the amount of fibrin degradation products in unwashed SMB was sufficient to account for the positive fibrin degradation product assays after infusion in this group. We conclude that infusion of unwashed SMB may confuse the interpretation of tests for disseminated intravascular coagulation or fibrinolysis. As this could lead to unnecessary blood component use and is preventable by washing before infusion, we recommend that the routine infusion of unwashed SMB no longer be employed.

Enhanced in vitro fibrinolytic activity of immobilized plasmin on collagen beads

Plasmin was immobilized on collagenous substrates using carbodiimide as a linking agent. The kinetics of soluble and immobilized plasmin were monitored by reacting them with the chromogenic substrate S-2251 (H-D-Val-Leu-Lys-pNA) in the presence and absence of a2-antiplasmin (a2-PI). The ability of immobilized plasmin to lyse synthetic clots formed from fibrinogen and thrombin was determined by detecting the formation of fibrin degradation products (FDP). The activity of immobilized plasmin was 0.02 casein units (CU)/mg of collagen. The kinetic analysis of soluble and immobilized plasmin in the presence and absence of a2-PI shows that while soluble plasmin activity was inhibited by the presence of a2-PI, the plasmin inhibitor did not interfere with the ability of immobilized plasmin to attack fibrin. In the absence of a2-PI, the ability of the immobilized plasmin to lyse synthetic clots was the same as that of soluble plasmin. In the presence of a2-PI, immobilized plasmin produced twice the amount of FDP as did soluble plasmin. The immobilized plasmin activity was stable for a period of at least 3 months.