scholarly journals Thrombolytic properties of Desmodus rotundus (vampire bat) salivary plasminogen activator in experimental pulmonary embolism in rats

Blood ◽  
1992 ◽  
Vol 79 (5) ◽  
pp. 1213-1217
Author(s):  
W Witt ◽  
B Baldus ◽  
P Bringmann ◽  
L Cashion ◽  
P Donner ◽  
...  
Keyword(s):  
Pulmonary Embolism ◽  
Plasminogen Activator ◽  
Tissue Type ◽  
Desmodus Rotundus ◽  
Type Plasminogen Activator ◽  
Blood Clots ◽  
Hemostatic Factors ◽  
The Difference ◽  
Vampire Bat

rDSPA alpha 1 (recombinant Desmodus salivary plasminogen activator alpha 1) is a recombinant protein corresponding to a natural plasminogen activator from the vampire bat Desmodus rotundus. The thrombolytic properties of rDSPA alpha 1 and tissue-type plasminogen activator (t-PA) were compared in a rat model of pulmonary embolism. Whole blood clots, produced in vitro and labeled with 125I-fibrinogen, were embolized into the lungs of anesthetized rats. Thrombolysis was calculated from the difference between initial clot radioactivity and that remaining in the lungs at 60 minutes. Blood was sampled for gamma counting, measurement of hemostatic factors, and plasminogen activator antigen levels. Thrombolysis at 3, 10, 30, and 100 nmol/kg intravenously (10% bolus, 90% over 60 minutes) amounted to 30% +/- 2%, 51% +/- 4%, 85% +/- 4%, 98% +/- 0% for rDSPA alpha 1 and 30% +/- 3%, 41% +/- 3%, 57% +/- 6%, 93% +/- 2% for t-PA (controls: 29% +/- 2%; mean +/- SEM, n greater than or equal to 6). t-PA at 100 nmol/kg significantly decreased fibrinogen, plasminogen, and alpha 2- antiplasmin levels by 33% +/- 7%, 38% +/- 8%, and 61% +/- 9%, whereas rDSPA alpha 1 at 100 nmol/kg only lowered alpha 2-antiplasmin significantly (by 29% +/- 6%). Compared with t-PA, rDSPA alpha 1 is the more potent and more clot selective (fibrin specific) thrombolytic agent. These results suggest that rDSPA alpha 1 may be safer and more efficacious than currently used thrombolytics.

scholarly journals Thrombolytic properties of Desmodus rotundus (vampire bat) salivary plasminogen activator in experimental pulmonary embolism in rats

Blood ◽  
1992 ◽  
Vol 79 (5) ◽  
pp. 1213-1217 ◽  
Author(s):  
W Witt ◽  
B Baldus ◽  
P Bringmann ◽  
L Cashion ◽  
P Donner ◽  
...  
Keyword(s):  
Pulmonary Embolism ◽  
Plasminogen Activator ◽  
Tissue Type ◽  
Desmodus Rotundus ◽  
Type Plasminogen Activator ◽  
Blood Clots ◽  
Hemostatic Factors ◽  
The Difference ◽  
Vampire Bat

Abstract rDSPA alpha 1 (recombinant Desmodus salivary plasminogen activator alpha 1) is a recombinant protein corresponding to a natural plasminogen activator from the vampire bat Desmodus rotundus. The thrombolytic properties of rDSPA alpha 1 and tissue-type plasminogen activator (t-PA) were compared in a rat model of pulmonary embolism. Whole blood clots, produced in vitro and labeled with 125I-fibrinogen, were embolized into the lungs of anesthetized rats. Thrombolysis was calculated from the difference between initial clot radioactivity and that remaining in the lungs at 60 minutes. Blood was sampled for gamma counting, measurement of hemostatic factors, and plasminogen activator antigen levels. Thrombolysis at 3, 10, 30, and 100 nmol/kg intravenously (10% bolus, 90% over 60 minutes) amounted to 30% +/- 2%, 51% +/- 4%, 85% +/- 4%, 98% +/- 0% for rDSPA alpha 1 and 30% +/- 3%, 41% +/- 3%, 57% +/- 6%, 93% +/- 2% for t-PA (controls: 29% +/- 2%; mean +/- SEM, n greater than or equal to 6). t-PA at 100 nmol/kg significantly decreased fibrinogen, plasminogen, and alpha 2- antiplasmin levels by 33% +/- 7%, 38% +/- 8%, and 61% +/- 9%, whereas rDSPA alpha 1 at 100 nmol/kg only lowered alpha 2-antiplasmin significantly (by 29% +/- 6%). Compared with t-PA, rDSPA alpha 1 is the more potent and more clot selective (fibrin specific) thrombolytic agent. These results suggest that rDSPA alpha 1 may be safer and more efficacious than currently used thrombolytics.

Ultrasound affects distribution of plasminogen and tissuetype plasminogen activator in whole blood clots in vitro

2004 ◽  
Vol 92 (11) ◽  
pp. 980-985 ◽  
Author(s):  
Lisa Gherardini ◽  
Christoph Mayer ◽  
Martin Gröschl ◽  
Christoph Kaun ◽  
Ewald Benes ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Weight Reduction ◽  
Whole Blood ◽  
Tissue Type ◽  
Fibrin Degradation Product ◽  
Acoustic Intensity ◽  
Type Plasminogen Activator ◽  
Blood Clots ◽  
D Dimer

SummaryUltrasound of 2 MHz frequency and 1.2 W/cm2 acoustic intensity was applied to examine the effect of sonication on recombinant tissue-type plasminogen activator (rt-PA)-induced thrombolysis as well as on the distribution of plasminogen and t-PA within whole blood clots in vitro. Thrombolysis was evaluated quantitatively by measuring clot weight reduction and the level of fibrin degradation product D-dimer (FDP-DD) in the supernatant. Weight reduction in the group of clots treated both with ultrasound and rt-PA was 35.2% ± 6.9% which is significantly higher (p<0.0001) than in the group of clots treated with rt-PA only (19.9% ± 4.3%). FDP-DD level in the supernatants of the group treated with ultrasound and rt-PA increased sevenfold compared to the group treated with rt-PA alone, (14895 ± 2513 ng/ml vs. 2364 ± 725 ng/ml). Localization of fibrinolytic components within the clots was accomplished by using gel-entrapping technique and immunohistochemistry. Spatial distributions of t-PA and plasminogen showed clearly that ultrasound promoted the penetration of rt-PA into thrombi significantly (p<0.0001), and broadened the zone of lysis from 8.9 ± 2.6 µm to 21.2 ± 7.2 µm. We speculate that ultrasound enhances thrombolysis by affecting the distribution of rt-PA within the clot.

scholarly journals In Vitro Simulation of Extremely Activated Thrombolysis

2008 ◽  
Vol 14 (2) ◽  
pp. 238-240
Author(s):  
Thomas W. Stief
Keyword(s):  
Pulmonary Embolism ◽  
Plasminogen Activator ◽  
Microtiter Plate ◽  
Massive Pulmonary Embolism ◽  
Tissue Type ◽  
Clot Lysis ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Life Threatening

A life-threatening thrombus in massive pulmonary embolism has to be eliminated within minutes. Extremely activated plasmatic fibrinolysis destroys such thrombi in time: 50 µL plasma clots were incubated with urokinase or tissue-type plasminogen activator and 50 µL pooled normal plasma. The microtiter plate clot lysis assay was performed. The time point at which 50% of the clot has been lysed is 4 minutes for 8333 IU/mL urokinase or an equimolar concentration of tissue-type plasminogen activator (52498 IU/mL = 105 µg/mL). The effective dose 50% at 5 minutes lysis time is about 800 nM (4320 IU/mL) urokinase or (27220 IU/mL = 54 µg/mL) tissue-type plasminogen activator. Addition of plasminogen to the plasmatic clot supernatant improves thrombolysis if 65 IU/mL of urokinase acts for 10 minutes. The risk for severe intracranial hemorrhage in massive thrombolysis might be much lower than the lethality of a massive pulmonary embolism. Extremely activated plasmatic thrombolysis could be clinically indicated.

Pharmacokinetics and Haemostatic Status During Consecutive Infusions of Recom binant Tissue-Type Plasminogen Activator in Patients with Acute Myocardial Infarction

1989 ◽  
Vol 61 (03) ◽  
pp. 497-501 ◽  
Author(s):  
E Seifried ◽  
P Tanswell ◽  
D Ellbrück ◽  
W Haerer ◽  
A Schmidt
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Plasminogen Activator ◽  
Peak Plasma ◽  
Peak Plasma Concentration ◽  
Tissue Type ◽  
Tissue Type Plasminogen Activator ◽  
Precise Control ◽  
Type Plasminogen Activator

SummaryPharmacokinetics and systemic effects of recombinant tissue type plasminogen activator (rt-PA) were determined during coronary thrombolysis in 12 acute myocardial infarction patients using a consecutive intravenous infusion regimen. Ten mg rt-PA were infused in 2 minutes resulting in a peak plasma concentration (mean ±SD) of 3310±950 ng/ml, followed by 50 mg in 1 h and 30 mg in 1.5 h yielding steady state plasma levels of. 2210±470 nglml and 930±200 ng/ml, respectively. All patients received intravenous heparin. Total clearance of rt-PA was 380±74 ml/min, t,½α was 3.6±0.9 min and t,½β was 16±5.4 min.After 90 min, in plasma samples containing anti-rt-PA-IgG to inhibit in vitro effects, fibrinogen was decreased to 54%, plasminogen to 52%, α2-antiplasmin to 25%, α2-macroglobulin to 90% and antithrombin III to 85% of initial values. Coagulation times were prolonged and fibrin D-dimer concentrations increased from 0.40 to 2.7 μg/ml. It is concluded that pharmacokinetics of rt-PA show low interpatient variability and that its short mean residence time in plasma allows precise control of therapy. Apart from its moderate effect on the haemostatic system, rt-PA appears to lyse a fibrin pool in addition to the coronary thrombus.

In Vitro Stability of a Tissue-Type Plasminogen Activator Mutant, BM 06.022, in Human Plasma

1994 ◽  
Vol 72 (06) ◽  
pp. 906-911 ◽  
Author(s):  
D C Rijken ◽  
E Groeneveld ◽  
M M Barrett-Bergshoeff
Keyword(s):  
Plasminogen Activator ◽  
Half Life ◽  
Polyacrylamide Gel Electrophoresis ◽  
Tissue Type ◽  
Single Chain ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Sds Page ◽  
Chain Form

SummaryBM 06.022 is a non-glycosylated mutant of human tissue-type plasminogen activator (t-PA) comprising only the kringle-2 and proteinase domains. The in vivo half-life of BM 06.022 antigen is 4- to 5-fold longer than that of t-PA antigen. The in vitro half-life of the activity of BM 06.022 at therapeutic concentrations in plasma is shorter than that of t-PA. In this study the inactivation of BM 06.022 in plasma was further investigated.Varying concentrations of BM 06.022 were incubated in plasma for 0-150 min. Activity assays on serial samples showed a dose-dependent decline of BM 06.022 activity with a half-life from 72 min at 0.3 μg/ml to 38 min at 10 μg/ml. SDS-polyacrylamide gel electrophoresis (SDS-PAGE) followed by fibrin autography showed the generation of several BM 06.022-complexes. These complexes could be completely precipitated with antibodies against Cl-inactivator, α2-antiplasmin and α1-antitrypsin.During the incubation of BM 06.022 in plasma, plasmin was generated dose-dependently as revealed by varying degrees of a2-anti-plasmin consumption and fibrinogen degradation. SDS-PAGE and immunoblotting showed that single-chain BM 06.022 was rapidly (i. e. within 45 min) converted into its two-chain form at concentrations of 5 μg/ml BM 06.022 and higher.In conclusion, BM 06.022 at therapeutic concentrations in plasma was inactivated by Cl-inactivator, a2-antiplasmin and a j-antitrypsin. The half-life of the activity decreased at increasing BM 06.022 concentrations, probably as a result of the generation of two-chain BM 06.022 which may be inactivated faster than the single-chain form.

Vampire Bat Salivary Plasminogen Activator Evokes Minimal Bleeding Relative to Tissue-Type Plasminogen Activator as Assessed by a Rabbit Cuticle Bleeding Time Model

1995 ◽  
Vol 73 (03) ◽  
pp. 478-483 ◽  
Author(s):  
Michael J Mellott ◽  
Denise R Ramjit ◽  
Inez I Stabilito ◽  
Timothy R Hare ◽  
Edith T Senderak ◽  
...  
Keyword(s):  
Factor Viii ◽  
Plasminogen Activator ◽  
Intravenous Administration ◽  
Bleeding Time ◽  
Bleeding Risk ◽  
Tissue Type ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Plasma Factor ◽  
Vampire Bat

SummaryCuticle bleeding time (CBT) measurements in anesthetized rabbits were performed to assess the potential bleeding risks which may accompany the administration of tissue-type plasminogen activator (tPA) or vampire bat salivary plasminogen activator (BatPA). The dose of BatPA or tPA used in this study, 42 nmol/kg, was previously shown to be efficacious using a rabbit femoral artery thrombosis model (Gardell et al, Circulation 84:244, 1991). CBT was determined by severing the apex of the nail cuticle and monitoring the time to cessation of blood flow. CBT was minimally elevated (1.6-fold, p<NS) following bolus intravenous administration of BatPA; in contrast, bolus intravenous administration of tPA dramatically elevated CBT (6.2-fold, p<0.05). Rabbits treated with tPA, but not BatPA, displayed profound activation of systemic plasminogen and consequent degradation of Factor VIII and fibrinogen. Elevations in CBT after the administration of tPA were reversed by the replenishment of plasma Factor VIII activity to 40% of control, but were unaffected by complete replenishment of plasma fibrinogen. The results of this study suggest that the administration of BatPA, at a dose that promotes thrombolysis, may evoke a minimal bleeding risk, relative to an equi-efficacious dose of tPA. In addition, the tPA-provoked proteolytic consumption of Factor VIII may be a key contributor to the heightened bleeding risk.

Vampire Bat Salivary Plasminogen Activator Promotes Robust Lysis of Plasma Clots in a Plasma Milieu Without Causing Fluid Phase Plasminogen Activation

1992 ◽  
Vol 68 (02) ◽  
pp. 165-169 ◽  
Author(s):  
Timothy R Hare ◽  
Stephen J Gardell
Keyword(s):  
Plasminogen Activator ◽  
Plasma Levels ◽  
Fluid Phase ◽  
Immunoblot Analysis ◽  
Tissue Type ◽  
Clot Lysis ◽  
Plasma Clot ◽  
Type Plasminogen Activator ◽  
Iodine 125 ◽  
Vampire Bat

SummaryVampire bat salivary plasminogen activator (BatPA), human tissue-type plasminogen activator (tPA) or streptokinase (SK) were incubated in human citrated plasma containing a plasma clot that was radiolabelled with iodine-125 fibrin(ogen). Complete clot dissolution by BatPA (30 nM) was associated with slight activation of “fluid phase” plasminogen; the plasma levels of functional fibrinogen and α2-antiplasmin decreased by only 8 and 19%, respectively. Addition of SK (3,600 IU/ml) to the clot-containing plasma caused complete clot lysis and massive activation of the “fluid phase” plasminogen, leading to >60 and 96% decreases of the functional levels of fibrinogen and α2-antiplasmin, respectively. Incubation of tPA (30 nM) in clot-containing plasma caused complete clot lysis as well as substantial activation of “fluid phase” plasminogen; the plasma levels of functional fibrinogen and α2-antiplasmin decreased by 45 and 79%, respectively. The profound degradation of fibrinogen in the SK and tPA but not BatPA-containing samples was confirmed by immunoblot analysis. Additional experiments showed that the presence of soluble clot lysate in plasma containing tPA enhanced the extent of fibrinogen degradation from 25% to >60%; the addition of soluble clot lysate to the plasma containing BatPA did not prompt further fibrinogen degradation. Finally, studies using exogenous α2-antiplasmin suggested that plasmin generated via tPA-mediated activation of “fluid phase” plasminogen does not play an important role in clot dissolution.

Behaviour and Quantitation of Extrinsic (Tissue-Type) Plasminogen Activator in Human Blood

1983 ◽  
Vol 50 (02) ◽  
pp. 518-523 ◽  
Author(s):  
C Kluft ◽  
A F H Jie ◽  
R A Allen
Keyword(s):  
Plasminogen Activator ◽  
Venous Occlusion ◽  
Tissue Type ◽  
Functional Assay ◽  
Uterine Tissue ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Baseline Values

SummaryFunctional assay of extrinsic (tissue-type) plasminogen activator (EPA) in plasma on fibrin plates was evaluated. Using specific quenching antibodies, we demonstrated the method to be specific for EPA under all conditions tested. Contributions of urokinases and intrinsic activators were excluded. The quantity of EPA in blood samples, as compared with purified uterine tissue activator, shows 1 blood activator unit (BAU) to be comparable to 0.93 ng.The median values for EPA activity for healthy volunteers were: baseline, 1.9 BAU/ml (n = 123); diurnal, 5.5 BAU/ml (n = 12); DDAVP administration, 11.7 BAU/ml (n = 39); exhaustive exercise, 25 BAU/ml (n = 24); venous occlusion (15 min), 35 BAU/ml (n = 61). A large inter-individual variation in EPA activity was found, while individual baseline values tended to be constant for periods of weeks.In vitro in blood EPA activity shows a disappearance of 50% in about 90 min at 37° C; EPA activity in euglobulin fractions is stable for ≤2 hr at 37° C.A rapid decrease in EPA activity occurs in vivo, as noted after extracorporal circulation and exercise stimulation (t½ decay, 2-5 min).

Absence of Synergism Between Tissue-Type Plasminogen Activator (t-PA), Single-Chain UrokinaseType Plasminogen Activator (scu-PA) and Urokinase on Clot Lysis in a Plasma Milieu In Vitro

1986 ◽  
Vol 56 (01) ◽  
pp. 035-039 ◽  
Author(s):  
D Collen ◽  
F De Cock ◽  
E Demarsin ◽  
H R Lijnen ◽  
D C Stump
Keyword(s):  
Human Plasma ◽  
Plasminogen Activator ◽  
Dose Response ◽  
Fibrinolytic System ◽  
Tissue Type ◽  
Clot Lysis ◽  
Single Chain ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator

SummaryA potential synergic effect of tissue-type plasminogen activator (t-PA), single-chain urokinase-type plasminogen activator (scuPA) or urokinase on clot lysis was investigated in a whole human plasma system in vitro. The system consisted of a human plasma clot labeled with 125I-fibrinogen, immersed in titrated whole human plasma, to which the thrombolytic agents were added. Clot lysis was quantitated by measurement of released 125I, and activation of the fibrinolytic system in the surrounding plasma by measurements of fibrinogen and α2-antiplasmin.t-PA, scu-PA and urokinase induced a dose-dependent and time-dependent clot lysis; 50 percent lysis after 2 h was obtained with 5 nM t-PA, 20 nM scu-PA and 12 nM urokinase. At these concentrations no significant activation of the fibrinolytic system in the plasma was observed with t-PA and scu-PA, whereas urokinase caused significant α2-antiplasmin consumption and concomitant fibrinogen degradation. The shape of the dose-response curves was different; t-PA and urokinase showed a log linear dose-response whereas that of scu-PA was sigmoidal.

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