A Novel Approach to Arterial Thrombolysis

Blood ◽  
1999 ◽  
Vol 94 (8) ◽  
pp. 2735-2743 ◽  
Author(s):  
Petr Klement ◽  
Peng Liao ◽  
Laszlo Bajzar
Keyword(s):  
Thrombolytic Therapy ◽  
Degradation Products ◽  
Antiplatelet Agents ◽  
Clot Lysis ◽  
Fibrin Degradation Products ◽  
Novel Approach ◽  
Tissue Plasminogen ◽  
Vessel Patency ◽  
Fibrinolysis Inhibitor ◽  
Arterial Thrombolysis

Achieving early, complete, and sustained reperfusion after acute myocardial infarction does not occur in approximately 50% of patients, even with the most potent established thrombolytic therapy. Bleeding is observed with increased concentrations of thrombolytics as well as with adjunctive antithrombotic and antiplatelet agents. A novel approach to enhance thrombolytic therapy is to inhibit the activated form of thrombin-activatable fibrinolysis inhibitor (TAFI), which attenuates fibrinolysis in clots formed from human plasma. Identification of TAFI in rabbit plasma facilitated the development of a rabbit arterial thrombolysis model to compare the thrombolytic efficacy of tissue-plasminogen activator (tPA) alone or with an inhibitor, isolated from the potato tuber (PTI), of activated TAFI (TAFIa). Efficacy was assessed by determining the time to patency, the time the vessel remained patent, the maximal blood flow achieved during therapy, the percentage of the original thrombus, which lysed, the percentage change in clot weight, the net clot accreted, and the release of radioactive fibrin degradation products into the circulation. The results indicate that coadministration of PTI and tPA significantly improved tPA-induced thrombolysis without adversely affecting blood pressure, activated partial thromboplastin time, thrombin clotting time, fibrinogen, or -2-antiplasmin concentrations. The data indicate that inhibitors of TAFIa may comprise novel and very effective adjuncts to tPA and improve thrombolytic therapy to achieve both clot lysis and vessel patency.

Activated thrombin-activatable fibrinolysis inhibitor attenuates spontaneous fibrinolysis of batroxobin-induced fibrin deposition in rat lungs

2003 ◽  
Vol 90 (09) ◽  
pp. 414-421 ◽  
Author(s):  
Chengliang Wu ◽  
Ningzheng Dong ◽  
Valdeci da Cunha ◽  
Baby Martin-McNulty ◽  
Katherine Tran ◽  
...  
Keyword(s):  
Rat Model ◽  
Degradation Products ◽  
Peak Plasma ◽  
Clot Lysis ◽  
Fibrin Deposition ◽  
Small Peptides ◽  
Peak Plasma Level ◽  
Fibrin Degradation Products ◽  
Fibrinolysis Inhibitor ◽  
Endogenous Fibrinolysis

SummaryStudies have shown that inhibition of TAFI by small peptides enhances pharmacological effects of tPA in animal models of thrombosis, suggesting that TAFI modulates the fibrinolytic system. In this study, we investigated the effect of activated human TAFI (TAFIa) on endogenous fibrinolysis in a rat model of intravascular fibrin deposition. 125I-labeled fibrinogen was injected intravenously followed by a bolus injection of batroxo-bin, a thrombin-like enzyme. Batroxobin cleaved fibrinogen to form insoluble fibrin that was deposited in tissues, including the lungs. This was shown by a decrease of radioactivity in the blood as a result of consumption of 125I-labeled fibrinogen and an elevation of radioactivity in the lungs 5 min following batroxobin administration. Endogenous fibrinolysis was detected by a gradual increase in radioactivity in the blood and a decrease in radioactivity in the lungs at 30 min, an indication of radio-labeled fibrin degradation products (FDPs) being released into the circulation from the tissues. Intravenous administration of human TAFIa dose-dependently attenuated the later phase reduction of radioactivity in the lungs. When the dose of TAFIa was 218 μg/kg, giving a peak plasma level of TAFIa 0.9 ± 0.05 μg/ml, the spontaneous fibrinolysis was completely prevented. These results provide direct evidence that an increase in circulating TAFIa impairs endogenous clot lysis in a rat model of fibrin deposition.

Thrombolysis with Streptokinase in Rabbits Dose Response, Fibrin-clot Specificity and Laboratory Evaluation of Fibrinolytic Effect

1974 ◽  
Vol 31 (02) ◽  
pp. 265-272
Author(s):  
Andrzej Nowak ◽  
Victor Gurewich
Keyword(s):  
Animal Model ◽  
Thrombolytic Therapy ◽  
Dose Response ◽  
Degradation Products ◽  
Fibrin Clot ◽  
Laboratory Evaluation ◽  
Clot Lysis ◽  
Excellent Correlation ◽  
Fibrin Degradation Products ◽  
High Degree

SummaryAn animal model was used in which venous thromboemboli of reproducible size could be formed. The effects of SK 500–50,000 units per hour were evaluated and compared to those of saline. Proportionately the greatest clot lysis occurred with the lowest doses of SK. In contrast to thrombolysis, significant fibrinogenolysis did not occur in any of the animals indicating a high degree of specificity of SK-induced activator for rabbit fibrin. An excellent correlation between the concentration of fibrin degradation products (fdp) measured by the serial dilution protamine sulfate test and the extent of clot lysis was found suggesting this to be a useful method for monitoring the effects of thrombolytic therapy. A method for the laboratory distinction of fdp from fibrin monomer was demonstrated.

A Plasma Clot Lysis Assay Based on the Release of Fibrin Degradation Products: Application to the Diagnosis of Hypofibrinolytic States

1990 ◽  
Vol 63 (01) ◽  
pp. 076-081 ◽  
Author(s):  
Pascale Gaussem ◽  
Sophie Gandrille ◽  
Pascale Molho-Sabatier ◽  
Loïc Capron ◽  
Jean-Noël Fiessinger ◽  
...  
Keyword(s):  
Degradation Products ◽  
Venous Occlusion ◽  
Lower Limbs ◽  
Clot Lysis ◽  
Plasma Clot ◽  
Vein Thrombosis ◽  
Fibrin Degradation Products ◽  
Before And After ◽  
Euglobulin Clot Lysis Time ◽  
Pai 1

SummaryUsing a monoclonal antibody-based assay, we measured the fibrin degradation product release in the supernatant of plasma clots obtained before and after venous occlusion (VO) in 30 patients with definite or suspected vascular thrombosis (19 definite and 2 suspected deep vein thrombosis, 6 recurrent superficial thrombophlebitis, 3 arterial occlusions of lower limbs). tPA and PAI-1 concentrations were determined using ELISA assays; the post-occlusion values were corrected for haemoconcentration. The increase in tPA during VO was correlated with haemoconcentration (r = 0.74), but 3 patients had ineffective VO (<2% increase in proteins). The fibrinolytic response to VO was evaluated using the shortening of the time necessary for the release of 200 μg of fibrin degradation products per mg of fibrinogen (Δ T 200). Two among the 27 patients with effective VO were bad responders with a Δ T 200 <3 h (whereas all the others had Δ T 200 >10 h). These patients had respectively a deficient tPA release (Δ tPA = 1 ng/ml) and an elevated PAI-1 level at rest (33 ng/ml). Several other patients were bad responders in terms of tPA release or of shortening of the euglobulin clot lysis time but they had a normal Δ T 200. This plasma clot test reflects the ability of free tPA to bind to fibrin (the amount of which depends on the level of tPA and PAI-1), and may be useful in the diagnosis of a hypofibrinolytic state.

MONOCLONAL ANTIBODIES OF THE IgM AND IgG CLASS SPECIFIC FOR CROSSLINKED FIBRIN DEGRADATION PRODUCTS

1987 ◽  
Author(s):  
P J Gaffney ◽  
L J Creighton ◽  
A Curry ◽  
B MacMahon ◽  
R Thorpe
Keyword(s):  
Monoclonal Antibodies ◽  
Thrombolytic Therapy ◽  
Epitope Mapping ◽  
Degradation Products ◽  
Subcutaneous Route ◽  
Fibrin Degradation Products ◽  
Conformational Epitopes ◽  
Immunoglobulin Class Switching ◽  
Unique Specificity ◽  
D Dimer

Monoclonal antibodies (mabs) to crosslinked fibrin degradation products (XL-FDP) having the general formula D/Y[X]nY/D (known as X-oligomer) and D-D (known as D dimer) have been raised in balb/C mice by both a novel mtrasplenic and a conventional subcutaneous route of immunisation and by combinations of both these procedures. Mabs to X-oligomers (NIBn 52 and NIBn 123) obtained by an intrasplenic procedure have been demonstrated to crossreact only with X-oligomer in a 2-site ELISA procedure and not with D dimer or whole fibrinogen and have been shown to be of value m the examination of clinical material obtained from patients with various types of thrombosis and have also been useful in monitoring the efficacy of thrombolytic therapy. The X-oligomer mabs are immunoglobulins of the M class. It was demonstrated that their unique specificity for conformational epitopes on the large X-oligomer fragments does not reside in the IgM structure since alterative immunisation procedures have been used to generate mabs of the IgG class which have the same specificity. Using immunoglobulin class switching in culture rather than during immunisation was suggested by certain cell lines which produced both IgM and IgG specific for X-oligomer. This latter point needs rigorous validation.Immunoglobulin G type mabs to highly purified D dimer were raised by conventional subcutaneous immunisation of balb/C mice. One of these, NIBn-11, was found to crossreact with PVC-immobilised X-oligomer and D dimer but not with fibrinogen. However NIBn-11 did not bind to D dimer in a 2-site ELISA procedure while crossreactmg quite avidly with X-oligomer. This suggests that the D dimer epitope to which NIBn-11 is directed is expressed in some conformations and not m others and that these conformations are always expressed in the complex X-oligomer group of fragments. These mabs, whilst of value in measuring certain unique fibrin fragments m plasma, are useful in the epitope mapping of fibrinogen/fibrin and their plasmm-mediated

PLASMA LEVELS OF FRAGMENT D-DIMER OF CROSSLINKED FIBRIN DURING THROMBOLYTIC THERAPY WITH RECOMBINANT TISSUE-TYPE PLASMINOGEN ACTIVATOR

1987 ◽  
Author(s):  
P Declerck ◽  
P Mombaerts ◽  
P Holvoet ◽  
D Collen
Keyword(s):  
Thrombolytic Therapy ◽  
Plasma Levels ◽  
Degradation Products ◽  
Fibrin Clot ◽  
Tissue Type ◽  
Fibrin Degradation Products ◽  
Type Plasminogen Activator ◽  
Rate Of Increase ◽  
Significant Difference ◽  
D Dimer

Plasma levels of crosslinked fibrin degradation products (XLDP) were measured before and at the end of the administration of rt-PA (40 to 100 mg over 1.5 to 8 hours) in healthy volunteers (n=5) and patients with deep venous thrombosis (DVT) (n=8), pulmonary embolism (PE) (n=16)and myocardial infarction(MI)(n=10). Determinations were performed using our newly developed ELISA, specific for crosslinked fibrin derivatives, based on two monoclonal antibodies (15C5 and 8D3H2) raised against purified human fragment D-dimer. All plasma samples were collected on citrate and trasylol. Results are expressed as mean and range of D-dimer equivalents (μg/ml).Baseline levels in patients with MI are only slightly elevated. The increased levels inDVT and PE are in agreement with previous studies. After infusion of rt-PA a small increase of XLDP is seen even innormal subjects. A very marked increasof XLDP is detected in patients with PE and DVT but not in patients with MI. This may reflect differences in the amounts of fibrin clot dissolved in these patient groups.No significant correlation was found between the increase of XLDP and success of therapy, although a significant difference in D-dimer levels was formed between the two groups with PE: successful (n=ll): 116 (range 61-192) vs. unsuccessful (n=5): 68 (36-155).Thus, XLDP are already elevated under baseline conditions in patients with DVT and PE and increase very markedly during thrombolytic therapy. The absolute levels after thrombolytic therapy do not strictly correlate with success of therapy. It could be useful to measure D-dimer levels during early stages of therapy, because the rate of increase of XLDP levels might correlate with the efficacy of thrombolytic treatment.

Effects of exercise and conditioning on clotting and fibrinolytic activity in men

1987 ◽  
Vol 62 (4) ◽  
pp. 1416-1421 ◽  
Author(s):  
E. W. Ferguson ◽  
L. L. Bernier ◽  
G. R. Banta ◽  
J. Yu-Yahiro ◽  
E. B. Schoomaker
Keyword(s):  
Fibrinolytic Activity ◽  
Blood Clotting ◽  
Degradation Products ◽  
Clot Lysis ◽  
Plasma Clot ◽  
Fitness Program ◽  
Fibrin Degradation Products ◽  
Before And After ◽  
Plasmin Inhibitor ◽  
Sedentary Subjects

Sixty healthy men in three physical fitness categories (sedentary, on no organized fitness program; joggers, running 5–15 miles/wk; and marathoners, running greater than 50 miles/wk) were evaluated for changes in blood clotting and fibrinolytic activity before and after maximum exercise on a treadmill according to the Bruce protocol. The rate of blood clotting, as measured by prothrombin times, partial thromboplastin times and thrombin times, was accelerated by exercise (all P less than 0.005). The ability of euglobulin clots and plasma clots to lyse incorporated 125I-fibrin, termed 125I-euglobulin clot lysis (IEL) and 125I-plasma clot lysis (IPCL), were used as indexes of fibrinolytic activity. Marathoners had greater increases in fibrinolytic activity with exercise (76% compared with 63% for joggers and 55% for sedentary subjects by IEL; 427% compared with 418% for joggers and 309% for sedentary subjects by IPCL; all P less than 0.05). Fibrin degradation products increased with exercise (P less than 0.005 for the total group of 60 subjects). The absolute concentrations of alpha 2-plasmin inhibitor, alpha 2-macroglobulin, and antithrombin III increased with exercise (all P less than 0.005), but when concentrations were corrected for acute shifts of plasma water during exercise, the quantity of these inhibitors actually decreased (all P less than 0.005). The changes in clotting assays with exercise were not significantly correlated with changes in whole blood lactate, blood pyruvate, or rectal temperatures. Fibrinolytic assays before and after exercise correlated poorly to moderately with blood lactates (IEL: r = 0.441 and r = 0.425, respectively; IPCL: r = 0.294 and r = 0.544, respectively.(ABSTRACT TRUNCATED AT 250 WORDS)

scholarly journals Fibrin fragment D-dimer and fibrinogen B beta peptides in plasma as markers of clot lysis during thrombolytic therapy in acute myocardial infarction

Blood ◽  
1990 ◽  
Vol 76 (7) ◽  
pp. 1341-1348 ◽  
Author(s):  
CM Lawler ◽  
EG Bovill ◽  
DC Stump ◽  
DJ Collen ◽  
KG Mann ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Degradation Product ◽  
Degradation Products ◽  
Tissue Type ◽  
Clot Lysis ◽  
Fibrin Degradation Product ◽  
Fibrin Degradation Products ◽  
Group 2 ◽  
D Dimer ◽  
Group 1

Abstract The validity of markers in plasma of in vitro thrombolysis was investigated in 12 patients with extensive fibrinogen breakdown (greater than 80%, group 1) and in 12 patients with minimal breakdown (less than 20%, group 2). The patients were treated with 100 mg of recombinant tissue-type plasminogen activator (rt-PA) in the “Thrombolysis in Myocardial Infarction II” (TIMI II) trial. Cross- linked fibrin degradation product levels were measured with two variant enzyme-linked immunosorbent assays (ELISAs), both using a fibrin fragment D-dimer specific capture antibody. In one instance, a tag antibody was used that cross-reacts with fibrinogen (pan-specific tag ELISA); in the other, the tag antibody was specific for fibrin fragment D (fibrin-specific tag ELISA). Apparent concentrations of cross-linked fibrin degradation products at baseline were within normal limits with both assays in most patients. At 8 hours after rt-PA infusion, the measured cross-linked fibrin degradation products were increased about twofold to fourfold in group 2 with both assays. However, in group 1, levels were significantly higher with the pan-specific tag ELISA (5.8 +/- 4.2 micrograms/mL) compared with the fibrin-specific tag ELISA (1.5 +/- 1.3 micrograms/mL). This observation was most likely a result of detection of fibrinogen degradation products in the pan-specific ELISA. Apparent levels of fibrinopeptide B beta 1–42, a marker of fragment X formation, increased during thrombolysis from 4.2 +/- 2.8 pmol/mL to 2,000 +/- 230 pmol/mL in group 1 and from 4.1 +/- 2.1 pmol/mL to 300 +/- 43 pmol/mL in group 2, and were correlated significantly with the extent of fibrinogen breakdown (r = -0.8). Fibrinopeptide beta 15–42 levels increased from 4.3 +/- 3 pmol/mL to 70 +/- 19 pmol/mL in group 1, but did not increase in group 2. The apparent increase in group 1 could be explained by cross-reactivity of fibrinopeptide B beta 1–42 in the fibrinopeptide beta 15–42 assay. We conclude that cross-linked fibrin degradation product levels as measured with a pan-specific tag ELISA and fibrinopeptide beta 15–42 levels as measured with certain monoclonal antibody-based ELISA are influenced by the extent of fibrinogen degradation. Fibrinopeptide B beta 1–42 is a marker specific for fibrinogen breakdown. Cross-linked fibrin degradation product levels, measured with a fibrin-specific tag ELISA, appear to be markers specific for thrombolysis. Consequently, assays similar to the fibrin- specific tag ELISA may provide more accurate information when correlated with clinical endpoints.

scholarly journals Hematologic and Coagulation Measurements in Autotransfused Blood

1977 ◽  
Author(s):  
F.N. McKenzie ◽  
W. Wall ◽  
R.O. Heimbecker ◽  
R. Barr ◽  
A. Robert
Keyword(s):  
Degradation Products ◽  
Autologous Blood ◽  
Significant Risk ◽  
Major Surgery ◽  
Clot Lysis ◽  
Plasma Hemoglobin ◽  
Fibrin Degradation Products ◽  
Excellent Preservation ◽  
The Mean

Reinfusion of blood shed during elective or emergency vascular surgery (autotransfusion) is an under utilized technique. This is due in part to doubts as to the quality of autotransfused blood and concern about the risk of inducing a coagulopathy in the recipient. We have measured coagulation and hematologic parameters in autotransfused blood in the recipient before and at intervals after operation in 62 patients, none of whom received bank blood or blood products at the time of the study. The patients were heparinized (3 mg/Kg) during operation and this was reversed by protamine at the end of the procedure. The salvaged blood was reinfused immediately after appropriate samples had been taken. The mean volume of blood autotransfused was 1.8L in 58 patients and 9.4L in 4 patients. There was excellent preservation of platelets and fibrinogen, normal levels being maintained both in the autotransfused blood and in the recipients. Values for fibrin degradation products and euglobulin clot lysis remained normal. The mean plasma hemoglobin in the autotransfused blood was 416 mg% and this was not correlated to the volume autotransfused. Partial thromboplastin time which was prolonged by heparin during surgery was consistently normal post-operatively. No patient developed complications which could be attributed to autotransfusion and, in particular, re-operation for post-operative bleeding was never required and wound hematoma was not seen. We conclude that autologous blood may be returned to patients in large amounts without significant risk using the technique described. The technique deserves wider application in major surgery.

The Kinetics of Activated Thrombin-Activatable Fibrinolysis Inhibitor with Respect to Plasminogen Binding Site Removal From Fibrin Degradation Products.

Blood ◽  
2009 ◽  
Vol 114 (22) ◽  
pp. 3185-3185
Author(s):  
Jonathan H. Foley ◽  
Michael E. Nesheim
Keyword(s):  
Binding Site ◽  
Binding Sites ◽  
Degradation Products ◽  
Catalytic Efficiency ◽  
Plasminogen Activation ◽  
Thrombin Activatable Fibrinolysis Inhibitor ◽  
Fibrin Degradation Products ◽  
Fibrinolysis Inhibitor ◽  
Arginine Residues ◽  
Kinetics Of

Abstract Abstract 3185 Poster Board III-122 TAFI (thrombin activatable fibrinolysis inhibitor, or carboxypeptidase U) is a plasma zymogen that can be activated by thrombin, thrombin-thrombomodulin or plasmin. When activated, TAFIa cleaves C-terminal lysine and arginine residues from plasmin modified fibrin (Fn'). Fn' as a cofactor increases the rate of plasminogen activation by 3-fold over intact fibrin and 3000-fold compared to in the absence of fibrin. Upon extensive treatment with TAFIa, the cofactor activity of TAFIa modified fibrin decreases by approximately 97%. Determining the kinetics of TAFIa will give insight into how much TAFIa is required to efficiently inhibit plasminogen activation and fibrinolysis. The kinetics of TAFIa on its primary physiological substrate were measured by exploiting the binding of plasminogen to fibrin degradation products (FDPs). Fluorescently labeled plasminogen (5IAF-Pg) was equilibrated with FDPs labeled with a quencher, QSY C5-maleimide (QSY-FDP). When 5IAF-Pg is bound to QSY-FDP a baseline fluorescence reading is obtained. When treated with TAFIa, plasminogen binding sites are removed from the QSY-FDP and the fluorescence increases. A model was used to convert the rate of fluorescence increase into the rate of Plasminogen binding site removal. The model includes two distinct binding sites on QSY-FDPs (C-terminal and internal lysines), only one of which is susceptible to removal by TAFIa (C-terminal lysine). 5IAF-Glu-Pg (fluorescent native plasminogen) binds to QSY-FDP with a Kd of 176nM and when QSY-FDP are treated with TAFIa the Kd increases to 1.06μM. It appears that 5IAF-Glu-Pg has the ability to weakly bind TAFIa-treated QSY-FDP, however, the capacity is greatly reduced. Similar binding constants were obtained for 5IAF-Lys-Pg (fluorescent plasmin-cleaved plasminogen) (Kd=92nM; Kd (+TAFIa)=1.55μM). The increase in Kd upon treatment of the QSY-FDP with TAFIa is similar to that observed with 5IAF-Glu-Pg, however, the capacity of the FDPs to bind 5IAF-Lys-Pg is relatively unchanged. The calculated rate of 5IAF-Glu-Pg binding site removal by TAFIa was determined at various QSY-FDP concentrations (0-2 μM). The data are hyperbolic in nature and when fit using the Michaelis-Menten model the kcat and Km of plasminogen binding site removal were 2.34 s-1 and 142.6nM, respectively, implying a catalytic efficiency of 16.41 μM-1s-1. The rate is sensitive to the TAFIa concentration with all TAFIa concentrations (50, 75 and 100pM) yielding similar kinetic parameters. The data described here suggest that TAFIa is very efficient in removing plasminogen binding sites. The catalytic efficiency of TAFIa toward QSY-FDP is 60-fold higher than reported for bradykinin, which was previously the best known substrate of TAFIa. This increased catalytic efficiency is due to a much lower Km (0.146 μM compared to 70.6 μM). These data are reflective of plasminogen site removal and not every C-terminal lysine or arginine cleaved by TAFIa is expected to be involved in plasminogen binding. Therefore, the catalytic efficiency of TAFIa reported here (16.41 μM-1s-1) is likely a lower limit for the true value. Disclosures No relevant conflicts of interest to declare.

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