Regulation of plasminogen activation in isolated perfused rat kidney

To better understand the mechanism and regulation of plasminogen activation within the kidney, the release and excretion of plasminogen activator activities was studied in the isolated perfused rat kidney in the absence and presence of plasminogen substrate. In the absence of plasminogen, the kidneys released a constant amount of plasminogen activator activity into both the urine and the perfusate. On continuous infusion of purified human plasminogen into the perfusate, the release of plasminogen activator activity into the urine slightly increased, and plasmin generated could be detected in both urine and perfusate. With the use of specific antibodies against the tissue-type (t-PA) and the urokinase-type plasminogen activator (u-PA), respectively, the activity in the perfusate could be identified as t-PA, whereas the activity in the urine could be ascribed to u-PA. A bolus injection of either antibody into the plasminogen-supplemented perfusion medium completely inhibited plasminogen activator activity and generation of plasmin in the vascular or tubular compartment. Furthermore, intrarenal inhibition of t-PA activity by the specific antibody significantly increased the concentration of plasminogen in the perfusate, indicating decreased consumption. This effect was accompanied by increased excretion of u-PA into the urine, suggesting that the availability of intact plasminogen in the renal circulation directly or indirectly might participate in the regulation of u-PA excretion into the urine.

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PLASMINOGEN ACTIVATOR ACTIVITY (PAA) IN THE ISOLATED PERFUSED RAT KIDNEY (IPRK)

10.1055/s-0038-1643177 ◽

1987 ◽

Author(s):

W Müllbacher ◽

M Maier ◽

B R Binder

Keyword(s):

Plasminogen Activator ◽

Rat Kidney ◽

Tissue Type ◽

Plasmin Activity ◽

Perfusion Fluid ◽

Tissue Type Plasminogen Activator ◽

Isolated Perfused Rat Kidney ◽

Type Plasminogen Activator ◽

Fibrin Plate ◽

Perfused Rat Kidney

Isolated rat kidneys perfused with albumin elaborate PAA into the urine as well as into the perfusate as assessed by the fibrin plate technique. Urinay PAA can be inhibited by addition of a monospecific antibody directed towards urokinase (uPA) while the activity in the perfusate is inhibited by an antibody against tissue type plasminogen activator (tPA). Infusion of plasminogen (45ug/g/min) into the albumin containing perfusion fluid is followed by the appearance of plasmin in the urine and perfusate and doubles PAA in the urine. Kidneys perfused with both plasminogen and the anti-urokinase antibody (0.5mg) excrete similar PAA and plasmin into the perfusate while these activities in the urine are completely abolished. Replacement of the anti-urokinase antibody by an anti-tPA antibody (0.5mg) abolishes PAA as well as plasmin activity in the perfusate and PAA in the urine is significantly decreased. From these data it is concluded that PAA in the urine of the isolated perfused rat kidney is due to urokinase and PAA in the perfusate is caused by tPA. The results suggest that plasmin activity in the perfusate might trigger increased secretion of urokinase into the urine

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Depression of Tissue-Type Plasminogen Activator and Enhancement of Urokinase-Type Plasminogen Activator as an Expression of Local Inflammation

Thrombosis and Haemostasis ◽

10.1055/s-0038-1656345 ◽

1992 ◽

Vol 68 (02) ◽

pp. 180-184 ◽

Cited By ~ 22

Author(s):

Emile J P Brommer ◽

Gerard Dooijewaard ◽

Ben A C Dijkmans ◽

Ferdinand C Breedveld

Keyword(s):

Plasminogen Activator ◽

Tissue Type ◽

Plasminogen Activation ◽

Single Chain ◽

Tissue Type Plasminogen Activator ◽

Type Plasminogen Activator ◽

Healthy Donors ◽

Urokinase Type Plasminogen Activator ◽

Knee Trauma ◽

Fibrinolytic Parameters

SummaryInflammatory processes are accompanied by extravascular deposition and breakdown of fibrin. We measured fibrinolytic parameters in synovial fluid (SF) and in plasma of 36 patients with rheumatoid arthritis (RA). As a control, SF of 13 patients with blunt knee trauma, and plasma of 17 healthy volunteers were studied. In RA patients, extravascular t-PA mediated plasminogen activation was depressed: mean SF tissue-type plasminogen activator (t-PA:Ag) concentration (2.1 ± 1.6 ng/ml) was four-fold lower, and plasminogen activator inhibitor (PAI) activity (284 ± 212%) four-fold higher than the plasma values of the same patients or of healthy donors. In contrast, u-PA related plasminogen activation was strongly enhanced: urokinase-type plasminogen activator (u-PA) antigen (23.1 ±12.4 ng/ml) was more than four-fold higher, single-chain u-PA (scu-PA) (5.3 ± 1.9 ng/ml) three-fold higher than in plasma of the same patients or of healthy donors, and active two-chain u-PA (tcu-PA) was detected in 14 of the 36 SF samples of RA patients. All of these changes in extravascular fibrinolytic parameters correspond with those induced by inflammatory mediators in cell cultures. In joint effusions of patients with a blunt knee trauma, the effects were intermediate: u-PA related parameters showed moderate changes in the same direction as in arthritis; t-PA antigen was also decreased. The only exception was that PAI was not increased. We conclude that the findings in traumatic effusions reflect transient effects as a reaction to trauma. In joint inflammation, the depressed t-PA mediated plasminogen activation, although more than compensated by the enhanced u-PA mediated plasminogen activation, results in protraction of fibrin removal. Besides, the enhanced u-PA activation might lead to proteolytic damage of the cartilage.

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The Role of the Plasminogen Activation System in Angioedema: Novel Insights on the Pathogenesis

Journal of Clinical Medicine ◽

10.3390/jcm10030518 ◽

2021 ◽

Vol 10 (3) ◽

pp. 518

Author(s):

Filomena Napolitano ◽

Nunzia Montuori

Keyword(s):

Plasminogen Activator ◽

Blood Clot ◽

Active Form ◽

Tissue Type ◽

Plasminogen Activation ◽

Scientific Debate ◽

Plasminogen Activation System ◽

Type Plasminogen Activator ◽

Urokinase Type Plasminogen Activator ◽

Normal Blood Flow

The main physiological functions of plasmin, the active form of its proenzyme plasminogen, are blood clot fibrinolysis and restoration of normal blood flow. The plasminogen activation (PA) system includes urokinase-type plasminogen activator (uPA), tissue-type PA (tPA), and two types of plasminogen activator inhibitors (PAI-1 and PAI-2). In addition to the regulation of fibrinolysis, the PA system plays an important role in other biological processes, which include degradation of extracellular matrix such as embryogenesis, cell migration, tissue remodeling, wound healing, angiogenesis, inflammation, and immune response. Recently, the link between PA system and angioedema has been a subject of scientific debate. Angioedema is defined as localized and self-limiting edema of subcutaneous and submucosal tissues, mediated by bradykinin and mast cell mediators. Different forms of angioedema are linked to uncontrolled activation of coagulation and fibrinolysis systems. Moreover, plasmin itself can induce a potentiation of bradykinin production with consequent swelling episodes. The number of studies investigating the PA system involvement in angioedema has grown in recent years, highlighting its relevance in etiopathogenesis. In this review, we present the components and diverse functions of the PA system in physiology and its importance in angioedema pathogenesis.

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Inhibition in Purified Systems and in Human Plasma of Chimaeric Plasminogen Activators Consisting of the NH2-Terminal Region of Tissue-Type Plasminogen Activator and the COOH-Terminal Region of UrokinaseType Plasminogen Activator

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647039 ◽

1988 ◽

Vol 60 (02) ◽

pp. 247-250 ◽

Cited By ~ 1

Author(s):

H R Lijnen ◽

L Nelles ◽

B Van Hoef ◽

F De Cock ◽

D Collen

Keyword(s):

Plasminogen Activator ◽

Rate Constants ◽

Plasminogen Activators ◽

Second Order ◽

Tissue Type ◽

Single Chain ◽

Chain Molecules ◽

Order Rate ◽

Type Plasminogen Activator ◽

Urokinase Type Plasminogen Activator

SummaryRecombinant chimaeric molecules between tissue-type plasminogen activator (t-PA) and single chain urokinase-type plasminogen activator (scu-PA) or two chain urokinase-type plasminogen activator (tcu-PA) have intact enzymatic properties of scu-PA or tcu-PA towards natural and synthetic substrates (Nelles et al., J Biol Chem 1987; 262: 10855-10862). In the present study, we have compared the reactivity with inhibitors of both the single chain and two chain variants of recombinant u-PA and two recombinant chimaeric molecules between t-PA and scu-PA (t-PA/u-PA-s: amino acids 1-263 of t-PA and 144-411 of u-PA; t-PA/u-PA-e: amino acids 1-274 of t-PA and 138-411 of u-PA). Incubation with human plasma in the absence of a fibrin clot for 3 h at 37° C at equipotent concentrations (50% clot lysis in 2 h), resulted in significant fibrinogen breakdown (to about 40% of the normal value) for all two chain molecules, but not for their single chain counterparts. Preincubation of the plasminogen activators with plasma for 3 h at 37° C, resulted in complete inhibition of the fibrinolytic potency of the two chain molecules but did not alter the potency of the single chain molecules. Inhibition of the two chain molecules occurred with a t½ of approximately 45 min. The two chain variants were inhibited by the synthetic urokinase inhibitor Glu-Gly-Arg-CH2CCl with apparent second-order rate constants of 8,000-10,000 M−1s−1, by purified α2-antiplasmin with second-order rate constants of about 300 M−1s−1, and by plasminogen activator inhibitor-1 (PAI-1) with second-order rate constants of approximately 2 × 107 M−1s−1.It is concluded that the reactivity of single chain and two chain forms of t-PA/u-PA chimaers with inhibitors is very similar to that of the single and two chain forms of intact u-PA.

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Physical Exercise Induces Enhancement of Urokinase-Type Plasminogen Activator (u-PA) Levels in Plasma

Thrombosis and Haemostasis ◽

10.1055/s-0038-1647459 ◽

1991 ◽

Vol 65 (01) ◽

pp. 082-086 ◽

Cited By ~ 24

Author(s):

G Dooijewaard ◽

A de Boer ◽

P N C Turion ◽

A F Cohen ◽

D D Breimer ◽

...

Keyword(s):

Physical Exercise ◽

Plasminogen Activator ◽

Maximal Exercise ◽

Normal Values ◽

Bicycle Ergometer ◽

Tissue Type ◽

Healthy Male ◽

Type Plasminogen Activator ◽

Urokinase Type Plasminogen Activator ◽

Fibrinolytic Potential

SummaryThe enhancement of the blood fibrinolytic potential by physical exercise is generally attributed to the release of tissue-type plasminogen activator (t-PA) from the vessel wall. In this study we have investigated the possible contribution of urokinase-type plasminogen activator (u-PA).Six healthy male volunteers (age 21–25 years) were screened for their ability to perform maximal exercise for their age-group for 12 min on a bicycle ergometer. Subsequently, on one occasion they were required to remain supine for 2 h (from 8.30 a. m. onwards) and on another they performed maximal exercise (from 9.00 a.m. onwards). During exercise an increase in u-PA antigen and plasmin-activatable pro-urokinase (proUK) activity, concurrent with t-PA antigen and euglobulin t-PA activity, was observed in all six volunteers, while at rest these parameters remained unaffected. Mean u-PA- and t-PA antigen increased, respectively, from 4.2 ± 1.0 ng/ml and 5.8 ± 2.1 ng/ml before exercise to 9.8 ± 3.0 ng/ml and 18.3 ± 3.8 ng/ml (peak). Mean plasminactivatable proUK activity and t-PA activity increased, respectively, from 2.1 ± 0.4 ng/ml and 0.3 ± 0.2 ng/ml before exercise to 4.3 ± 1.7 ng/ml and 7.2 ± 4.0 ng/ml (peak). The increases were statistically significant throughout (paired t-test, pre vs post, antigen P <0.005 and activity P <0.02). After cessation of exercise u-PA and t-PA declined concurrently to normal values with a 50"/" decay in about 5 min. In conclusion, we found that both u-PA antigen and plasmin-activatable proUK activity are, concurrently with t-PA, enhanced upon exercise and, therefore, we consider that u-PA also contributes to – and co-operates in – the enhancement of the blood fibrinolytic potential and activity under these conditions.

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Evolution of Urokinase-Type Plasminogen Activator (u-PA) and Tissue-Type Plasminogen Activator (t-PA) in Orthotopic Liver Transplantation (OLT)

Thrombosis and Haemostasis ◽

10.1055/s-0038-1651548 ◽

1993 ◽

Vol 69 (01) ◽

pp. 056-059 ◽

Cited By ~ 2

Author(s):

G Himmelreich ◽

G Dooijewaard ◽

P Breinl ◽

W O Bechstein ◽

P Neuhaus ◽

...

Keyword(s):

Liver Transplantation ◽

Plasminogen Activator ◽

Orthotopic Liver Transplantation ◽

Tissue Type ◽

Bleeding Complications ◽

Activity Levels ◽

Tissue Type Plasminogen Activator ◽

Type Plasminogen Activator ◽

Urokinase Type Plasminogen Activator ◽

Anhepatic Phase

SummaryIn orthotopic liver transplantation (OLT) hyperfibrinolysis seems to be of causative importance for intra- and postoperative bleeding. Although recently hyperfibrinolysis has been successfully reduced by intraoperative aprotinin treatment, small increases of fibrinolysis still remain during OLT. Originally, tissue-type plasminogen activator (t-PA) was considered to be responsible for the increases, but the efficacy of aprotinin which inhibits besides plasmin also kallikrein and urokinase-type plasminogen activator (u-PA) suggested also a role for the intrinsic and contact system-dependent plasminogen activators. We investigated the role of u-PA. From 29 patients undergoing OLT with intraoperative aprotinin infusion arterial blood samples were taken at 7 different time points. The preoperative median values for u-PA antigen (u-PA Ag) and plasmin-activatable single-chain u-PA (scu-PA) levels, which were more than 2-fold above normal (both: p <0.01), decreased slightly during the preanhepatic phase and remained unchanged during the anhepatic phase. With reperfusion of the graft liver the two levels decreased significantly (p = 0.0003 and p = 0.006, respectively) to almost normal values, probably due to clearance by the graft liver. Active two-chain u-PA (tcu-PA) was preoperatively 2-fold above the detection limit, remained stable during the preanhepatic phase and increased 2-fold in the anhepatic phase (p = 0.0018). As expected tcu-PA also relapsed upon reperfusion, but to the preoperatively enhanced level, possibly caused by sustained activation of scu-PA by cathepsin B. t-PA activity levels were at the upper end of the normal range preoperatively, slightly increased during preanhepatic and anhepatic phases and decreased significantly with reperfusion. The increases in tcu-PA and t-PA activities during the anhepatic phase coincided with greatly increased fibrinolysis as demonstrated by thrombelastography, indicating that both u-PA and t-PA are involved in the development of fibrinolysis during OLT.One patient was excluded from statistical evaluations because preoperative u-PA Ag, scu-PA, tcu-PA and t-PA activity levels were much higher than in the other 28 patients. In the investigated group this patient was the only one with diffuse peritonitis intraoperatively and severe bleeding complications postoperatively which made retransplantation mandatory.

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