scholarly journals Optimization of Catheter Based rtPA Thrombolysis in a Novel In Vitro Clot Model for Intracerebral Hemorrhage

2017 ◽  
Vol 2017 ◽  
pp. 1-8 ◽  
Author(s):  
Naureen Keric ◽  
Julia Masomi-Bornwasser ◽  
Hendrik Müller-Werkmeister ◽  
Sven Rainer Kantelhardt ◽  
Jochem König ◽  
...  
Keyword(s):  
Intracerebral Hemorrhage ◽  
Dose Response ◽  
Blood Clot ◽  
Alternative Therapy ◽  
Optimal Dose ◽  
Clot Lysis ◽  
Response Analysis ◽  
In Vitro Investigation ◽  
Optimal Drug

Hematoma lysis with recombinant tissue plasminogen activator (rtPA) has emerged as an alternative therapy for spontaneous intracerebral hemorrhage (ICH). Optimal dose and schedule are still unclear. The aim of this study was to create a reliable in vitro blood clot model for investigation of optimal drug dose and timing. An in vitro clot model was established, using 25 mL and 50 mL of human blood. Catheters were placed into the clots and three groups, using intraclot application of rtPA, placebo, and catheter alone, were analyzed. Dose-response relationship, repetition, and duration of rtPA treatment and its effectiveness in aged clots were investigated. A significant relative end weight difference was found in rtPA treated clots compared to catheter alone (p=0.002) and placebo treated clots (p<0.001). Dose-response analysis revealed 95% effective dose around 1 mg rtPA in 25 and 50 mL clots. Approximately 80% of relative clot lysis could be achieved after 15 min incubation. Lysis of aged clots was less effective. A new clot model for in vitro investigation was established. Our data suggest that current protocols for rtPA based ICH therapy may be optimized by using less rtPA at shorter incubation times.

Dependence of Blood Clot Lysis on the Mode of Transport of Urokinase into the Clot - A Magnetic Resonance Imaging Study in Vitro

1991 ◽  
Vol 65 (05) ◽  
pp. 549-552 ◽  
Author(s):  
A Blinc ◽  
G Planinšič ◽  
D Keber ◽  
O Jarh ◽  
G Lahajnar ◽  
...  
Keyword(s):  
Magnetic Resonance Imaging ◽  
Magnetic Resonance ◽  
Pressure Difference ◽  
Volume Flow Rate ◽  
Blood Clot ◽  
Linear Regression Analysis ◽  
Imaging Study ◽  
Clot Lysis ◽  
Resonance Imaging

SummaryMagnetic resonance imaging was employed to study the dependence of clot lysing patterns on two different modes of transport of urokinase into whole blood clots. In one group of clots (nonperfused clots, n1 = 10), access of urokinase to the fibrin network was possible by diffusion only, whereas in the other group (perfused clots, n2 = 10) bulk flow of plasma containing urokinase was instituted through occlusive clots by a pressure difference of 3 .7 kPa (37 cm H2O) across 3 cm long clots with a diameter of 4 mm. It was determined separately that this pressure difference resulted in a volume flow rate of 5.05 ± 2.4 × 10−2 ml/min through occlusive clots. Perfused clots diminished in size significantly in comparison to nonperfused ones already after 20 min (p <0.005). Linear regression analysis of two-dimensional clot sizes measured by MRI showed that the rate of lysis was more than 50-times faster in the perfused group in comparison to the nonperfused group. It was concluded that penetration of the thrombolytic agent into clots by perfusion is much more effective than by diffusion. Our results might have some implications for understanding the differences in lysis of arterial and venous thrombi.

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.

Effect of Heparin on TAFI-Dependent Inhibition of Fibrinolysis: Relative Importance of TAFIa Generated by Clot-Bound and Fluid Phase Thrombin

2002 ◽  
Vol 88 (08) ◽  
pp. 282-287 ◽  
Author(s):  
Anna Pentimone ◽  
Bianca Binetti ◽  
Marialisa Cramarossa ◽  
Donatella Piro ◽  
Nicola Semeraro ◽  
...  
Keyword(s):  
Thrombin Generation ◽  
Blood Clot ◽  
Fluid Phase ◽  
Clot Lysis ◽  
Relative Importance ◽  
Thrombin Activatable Fibrinolysis Inhibitor ◽  
Dependent Inhibition ◽  
Fibrinolysis Inhibitor ◽  
Dependent Mechanism

SummaryHeparin has been proposed to enhance thrombolysis by inhibiting thrombin-dependent generation of activated TAFI (thrombin activatable fibrinolysis inhibitor), a carboxypeptidase that inhibits fibrinolysis. We evaluated the effect of heparin in an in vitro thrombolysis model consisting of a radiolabelled blood clot submerged in defibrinated plasma. Fibrinolysis was induced by adding t-PA (250 ng/ml) and calcium to the plasma bath. Control experiments indicated that thrombin generation induced by recalcification caused significant TAFI activation and inhibited clot lysis. Heparin (up to 1 U/ml), added to the plasma bath, failed to enhance clot lysis. Thrombin generation in the fluid phase was totally inhibited by heparin at concentrations > 0.5 U/ml. In contrast, thrombin generation on the clot surface was not inhibited by heparin (1 U/ml). TAFIa generation did occur in heparin-containing samples (1 U/ml) and amounted to about 10% of TAFIa formed in control samples. This low amount of TAFIa did exert antifibrinolytic activity as indicated by the observation that the addition of a specific TAFIa inhibitor (PTI) along with heparin enhanced clot lysis. Hirudin (10 µg/ml), at variance with heparin, inhibited clot-bound thrombin and enhanced clot lysis. These data show that heparin is unable to stimulate fibrinolysis through a TAFI-dependent mechanism, most likely because of its inefficiency in inhibiting thrombin generation on the clot surface. Moreover, they suggest that clot-bound thrombin plays a major role in TAFI-mediated inhibition of fibrinolysis through “localized” TAFIa generation.

In vitro whole blood clot lysis by rt-PA is inversely correlated with baseline plasma levels of t-PA antigen

1994 ◽  
Vol 8 ◽  
pp. 43
Author(s):  
M. Colucci ◽  
S. Scopece ◽  
A. Gelato ◽  
L.G. Cavallo ◽  
N. Semeraro
Keyword(s):  
Whole Blood ◽  
Plasma Levels ◽  
Blood Clot ◽  
Clot Lysis

scholarly journals Novel Fibrinolytic Protease Producing Streptomyces radiopugnans VITSD8 from Marine Sponges

Marine Drugs ◽  
2019 ◽  
Vol 17 (3) ◽  
pp. 164 ◽  
Author(s):  
Dhamodharan D ◽  
Jemimah S ◽  
Merlyn S ◽  
Subathra C
Keyword(s):  
Tamil Nadu ◽  
Specific Activity ◽  
Blood Clot ◽  
Exchange Chromatography ◽  
Marine Sponges ◽  
Protease Production ◽  
Clot Lysis ◽  
Carbon And Nitrogen ◽  
Lysis Activity

Fibrinolytic enzymes have received more attention due to their medicinal potential for thrombolytic diseases. The aim of this study is to characterize the in vitro fibrinolytic nature of purified protease producing Streptomyces radiopugnans VITSD8 from marine brown tube sponges Agelas conifera. Three varieties of sponge were collected from the Rameshwaram Sea coast, Tamil Nadu, India. The fibrinolytic activity of Streptomyces sp. was screened and determined by casein plasminogen plate and fibrin plate methods respectively. The crude caseinolytic protease was purified using ammonium sulfate fractionation, affinity and ion-exchange chromatography. Based on the morphological, biochemical, and molecular characterization, the isolate VITSD8 was confirmed as Streptomyces radiopugnans. Maltose and peptone were found to be the best carbon and nitrogen sources for the production of fibrinolytic protease. The carbon and nitrogen source peptone showed (781 U/mL) enzyme activity. The optimum pH and temperature for fibrinolytic protease production was found to be 7.0 and 33 °C respectively. The purified enzyme showed a maximum specific activity of 3891 U. The blood clot lysis activity was compared with the standard, and it was concluded that a minimum of 0.18 U (10 µL) of purified protease was required to dissolve the blood clot. This is the first report which exploits the fibrinolytic protease activity of Streptomyces radiopugnans VITSD8 extracted from a marine sponge. Hence the investigation suggests a potential benefit of purified fibrinolytic protease which will serve as an excellent clot buster alternative.

scholarly journals An exposure–response analysis based on rifampin suggests CYP3A4 induction is driven by AUC: an in vitro investigation

Xenobiotica ◽  
2016 ◽  
Vol 47 (8) ◽  
pp. 673-681 ◽  
Author(s):  
Cheng Chang ◽  
Xin Yang ◽  
Odette A. Fahmi ◽  
Keith A. Riccardi ◽  
Li Di ◽  
...  
Keyword(s):  
Response Analysis ◽  
Exposure Response ◽  
In Vitro Investigation ◽  
Cyp3a4 Induction

scholarly journals A preliminary investigation of in vitro anti-thrombotic and anti-platelet activity of Pinus Gerardiana

2017 ◽  
Vol 4 (1) ◽  
pp. 1098 ◽  
Author(s):  
Atta-ur Rehman ◽  
Sara Naz ◽  
Muhammad Zaman ◽  
Syed Saeed-ul-Hassan ◽  
Javed Iqbal ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Blood Clot ◽  
Preliminary Investigation ◽  
Circulatory System ◽  
Clot Lysis ◽  
Platelet Activity ◽  
In Vivo Models ◽  
The Stability

Introduction: Hemostasis is a process which preserves the stability of a closed and high-pressure circulatory system after any vascular injury. Circulating platelets are recruited to the site of injury, where they develop a major component of the developing thrombus, blood clotting, started by tissue factor, concludes in the generation of thrombin and fibrin. Thrombosis is a serious event in the arterial diseases and a major cause in the development of myocardial infarction, stroke and venous thrombo-embolism which justify prominent morbidity and mortality rate. The knowledge of molecular and cellular mechanism of the formation of thrombus has developed considerably in the recent studies by using different in-vitro and in-vivo models of diseases. P. gerardiana nut oil has been reported to possess anti-bacterial, anti-fungal, anti-viral, anti-septic, anti-neuralgic, diuretic, expectorant, hypertensive properties. However, hardly, any data is available regarding effects of nut oil on platelet function. In this study, fibrinolytic activity and effect on platelet aggregation were investigated. Method: P. gerardiana nut oil was extracted by using n-Hexane and then concentrated by rotary evaporator. Anti-thrombotic and fibrinolytic activities were evaluated on blood clot formation. Effects on platelet aggregation of the oil were determined based on collagen or epinephrine induced platelet aggregation. Results: P. gerardiana caused blood clot lysis in-vitro. P. gerardiana nut oil inhibited collagen dependent platelet aggregation while accelerated the epinephrine dependent platelet aggregation. In vitro whole blood coagulation was also reduced. In vivo P. gerardiana nut oil has no significant effect on blood cell indices. Conclusion: P. gerardiana nuts oil can be an effective therapy for the treatment of cardiovascular disorders and thromboembolism.

Hypersensitivity To Exogenous Arachidonic Acid (Aa) And Redistribution Of Fatty Acids In Platelets From Women On The Pill

1981 ◽  
Author(s):  
G Di Minno ◽  
M T Tacconi ◽  
M C Roncaglioni ◽  
B Sadurska ◽  
J Pangrazzi ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Blood Clot ◽  
Factor Xa ◽  
Treated Group ◽  
Clot Lysis ◽  
Platelet Response ◽  
Antigenic Activity ◽  
Plasma Fatty Acid Composition ◽  
Before And After

Oral contraceptive (OC) treatment is associated with an increased thrcmbotic risk, the mechanism of which remains still unclear. We have investigated the platelet response to exogenous AA and the plasma and platelet lipid composition in eight healthy women (aged 18-29 y) before and after six month OC treatment with a canbination of d-norgestrel (0.25 mg) and ethynilestradiol (0.05 mg). The threshold aggregating concentration of AA was significantly reduced in platelets of women after 6 months of OC treatment (0.30±0.04 mM versus 0.65 ± 0.08 mM, p < 0.001) whereas it was unchanged in a group of 10 control women, matched for age with the OC treated group and tested twice, with a 6-month interval (0.48 ± 0.04 versus 0.50 ± 0.04). In the same group of patients, seme clotting and fibrinolytic parameters, namely the Normotest, the biological and antigenic activity of Antithranbin III, the anti factor Xa biological activity, the diluted whole blood clot lysis time, were completely unmodified by OC treatment.In platelets AA increased both in phospholipid and neutral lipid fractions. In plasma the pool of polyunsaturated fatty acids increased at the expense of the saturated pool. In particular, AA increased slightly but significantly in free-fatty acids and phospholipid fractions.This data indicates that during OC treatment changes in in vitro platelet aggregatory responses may be associated with modifications of platelet and plasma fatty acid composition. Such changes may contribute to the thrcmbotic tendency associated with OC treatment.

scholarly journals Preparation of Peptide and Recombinant Tissue Plasminogen Activator Conjugated Poly(Lactic-Co-Glycolic Acid) (PLGA) Magnetic Nanoparticles for Dual Targeted Thrombolytic Therapy

2020 ◽  
Vol 21 (8) ◽  
pp. 2690 ◽  
Author(s):  
Huai-An Chen ◽  
Yunn-Hwa Ma ◽  
Tzu-Yuan Hsu ◽  
Jyh-Ping Chen
Keyword(s):  
Magnetic Nanoparticles ◽  
Plasminogen Activator ◽  
Tissue Plasminogen Activator ◽  
Glycolic Acid ◽  
Blood Clot ◽  
Recombinant Tissue Plasminogen Activator ◽  
Clot Lysis ◽  
High Dose ◽  
Tissue Plasminogen

Recombinant tissue plasminogen activator (rtPA) is the only thrombolytic agent that has been approved by the FDA for treatment of ischemic stroke. However, a high dose intravenous infusion is required to maintain effective drug concentration, owing to the short half-life of the thrombolytic drug, whereas a momentous limitation is the risk of bleeding. We envision a dual targeted strategy for rtPA delivery will be feasible to minimize the required dose of rtPA for treatment. For this purpose, rtPA and fibrin-avid peptide were co-immobilized to poly(lactic-co-glycolic acid) (PLGA) magnetic nanoparticles (PMNP) to prepare peptide/rtPA conjugated PMNPs (pPMNP-rtPA). During preparation, PMNP was first surface modified with avidin, which could interact with biotin. This is followed by binding PMNP-avidin with biotin-PEG-rtPA (or biotin-PEG-peptide), which was prepared beforehand by binding rtPA (or peptide) to biotin-PEG-maleimide while using click chemistry between maleimide and the single –SH group in rtPA (or peptide). The physicochemical property characterization indicated the successful preparation of the magnetic nanoparticles with full retention of rtPA fibrinolysis activity, while biological response studies underlined the high biocompatibility of all magnetic nanoparticles from cytotoxicity and hemolysis assays in vitro. The magnetic guidance and fibrin binding effects were also confirmed, which led to a higher thrombolysis rate in vitro using PMNP-rtPA or pPMNP-rtPA when compared to free rtPA after static or dynamic incubation with blood clots. Using pressure-dependent clot lysis model in a flow system, dual targeted pPMNP-rtPA could reduce the clot lysis time for reperfusion by 40% when compared to free rtPA at the same drug dosage. From in vivo targeted thrombolysis in a rat embolic model, pPMNP-rtPA was used at 20% of free rtPA dosage to restore the iliac blood flow in vascular thrombus that was created by injecting a blood clot to the hind limb area.

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