On the Fibrinolytic System in Aged Rats, and Its Reactivity to Endotoxin and Cytokines

1992 ◽  
Vol 67 (06) ◽  
pp. 697-701 ◽  
Author(s):  
J J Emeis ◽  
A Brouwer ◽  
R J Barelds ◽  
M A Horan ◽  
S K Durham ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Fibrinolytic System ◽  
Tissue Type ◽  
High Dose ◽  
Base Line ◽  
Aged Rats ◽  
Tissue Type Plasminogen Activator ◽  
Young Rats ◽  
Type Plasminogen Activator

SummaryAged rats are more susceptible to endotoxin-induced effects, including microthrombosis and platelet aggregation, than are young rats. To investigate whether changes in the fibrinolytic system might be involved, we investigated the fibrinolytic activity in plasma euglobulin fractions and tissues (lung and heart) of young (6-months old) and aged (24-months old) rats under baseline conditions and after challenge with endotoxin. Aged rats had lower plasma levels of tissue-type plasminogen activator (t-PA) and of urokinase-type PA (u-PA) activity. PA inhibitor (PAI) activity was higher in the plasma of aged rats, as was t-PA activity in lung and heart.Rats were treated with either a low dose (1 μg/kg) or a high dose (10 mg/kg) of endotoxin. Both treatments induced a transient phase of increased blood fibrinolytic activity, as evidenced by higher levels of tissue-type plasminogen activator (t-PA) activity and decreased levels of PA inhibitor (PAI) activity. Over time, the fibrinolytic activity decreased, probably due to increased levels of PA inhibitor.Both the early increase in t-PA activity, and the subsequent increase in PAI activity, were more pronounced in the aged rats, as compared with the younger rats, after the high dose of endotoxin. The aged rats also responded to an injection of interleukin-1β or tumor necrosis factor-α with a larger increase of PAI activity than did the younger rats.Together the data suggest that, compared to young rats, aged rats have a decreased base-line plasma fibrinolytic activity, while their fibrinolytic system is more responsive to challenge by endotoxin and cytokines.

EFFECTS OF INTRAVENOUS ADMINISTRATIONOF A TISSUE-TYPE PLASMINOGEN ACTIVATOR (AK-124) IN ACUTE MYOCARDIAL INFARCTION, INCLUDING CHANGES IN BLOOD COAGULATION AND FIBRINOLYTIC ACTIVITY.- PRELIMINARY REPORT

1987 ◽  
Author(s):  
T Honda ◽  
M Aosaki ◽  
T Tanaka ◽  
M Aosaki ◽  
T Uchida ◽  
...  
Keyword(s):  
Myocardial Infarction ◽  
Acute Myocardial Infarction ◽  
Blood Coagulation ◽  
Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Tissue Type ◽  
Base Line ◽  
Tissue Type Plasminogen Activator ◽  
Human Lung Cells ◽  
Type Plasminogen Activator

We administered a tissue-type plasminogen activator (t-PA) intravenously to 10 patients with acute myocardial infarction (AMI), within 6 hours after the onset of symptoms, and then examined the state of reperfusion by coronary arterio graphy (CAG), and observed changes in blood coagulation and fibrinolytic activity to evaluate the drug effects. AK-124 (produced by Asahi Chemical Industry and Kowa Co., Ltd.in collaboration), a t-PA produced the by tissue cultureof normal human lung cells, was given in a dosage of48,000_576,000 A.K. units by intravenous infusionover 30_45 minutes. In 7 patients who received t-PA, areflow or improved flow was detected on CAG. In t-PAtreated patients, euglobulin lysis activity clearly increased, euglobulin lysis time clearly shortened, and D-dimer increased. After t-PA treatment, the levels of circulating fibrinogen and a2-plasmin inhibitor decreased by an average of 12%, and 14% of base-line values respectively, but plasminogen showed no detectable change. A hematoma at the site of the catheter insertion was observed in one patient. These observations suggest that t-PA has a higher specificity for fibrin bound plasminogen than for plasma plasminogen, and produces coronary thrombolysis without causing systemic fibrinolysis, at least with the above dosage.

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.

FIBRINOLYSIS AFTER HEART TRANSPLANTATION

1987 ◽  
Author(s):  
J A Páramo ◽  
R Arcas ◽  
J Fernández ◽  
J Herreros ◽  
R Llorens ◽  
...  
Keyword(s):  
Plasminogen Activator ◽  
Fibrinolytic Activity ◽  
Cardiac Transplantation ◽  
Degradation Products ◽  
Plasminogen Activator Inhibitor ◽  
Tissue Type ◽  
Inhibitor Activity ◽  
Tissue Type Plasminogen Activator ◽  
Type Plasminogen Activator ◽  
Activator Inhibitor

Some aspects of the function of the fibrinolytic system were investigated in 12 patients undergoing cardiac transplantation. Plasminogen, euglobulin fibrinolytic activity (EFA), tissue-type plasminogen activator (t-PA), plasminogen activator inhibitor activity (PAI),α2-antiplasmin (α2-Ap) and fibrinogen degradation products (FDP) were determined preo-peratively and on postoperative days 1 and 5. Results showed a significant decrease of plasminogen (p <0.005), EFA (p <0.0001) and t-PA (p ^.0.001) on postoperative day 1 as compared to the baseline value, followed by recovery on day 5. There was a significant increase of PAI (p < 0 . 005) , α2-AP (p <0.0001) and FDP (p < 0.02) on postoperative day 1 as compared to the preoperative value. PAI and FDP reached the baseline value on postoperative day 5, but α2AP also increased on postoperative day 5. Our data show that there is an impairment in blood fibrinolytic activity early after cardiac transplantation, mainly related to a decrease of plasminogen and t-PA and a increase of PAI and α2AP. The clinical relevance of these data needs further evaluation.

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