RESUMEN
Deficiencies or excessive activation of the fibrinolytic system can result in severe, lifelong bleeding disorders. The most severe clinical phenotype is caused by α2-Antiplasmin (α2-AP) deficiency which results in excess fibrinolysis due to the inability to inhibit plasmin. Another bleeding disorder due to a defect in the fibrinolytic pathway results from Plasminogen activator inhibitor-1 (PAI-1) deficiency causing enhanced fibrinolysis due to the decreased inhibition of plasminogen activators resulting in increased conversion of plasminogen to plasmin. Both these disorders are rare and have an autosomal recessive pattern of inheritance. They can remain undetected as routine coagulation and platelet function tests are normal. A unique gain-of-function defect in fibrinolysis causes the Quebec platelet disorder (QPD) which is characterized by profibrinolytic platelets containing increased urokinase-type plasminogen activator (uPA) in the α-granules. A high index of suspicion based on clinical phenotype along with the availability of specialized hemostasis testing is required for timely and accurate diagnosis. Antifibrinolytic agents, such as tranexamic acid or ε-aminocaproic acid, are the mainstays of treatment which inhibit fibrinolysis by preventing the binding of plasminogen to fibrin and thereby stabilizing the fibrin clot. The purpose of this review is to summarize the pathogenesis, clinical phenotype, approaches to diagnosis and treatment for these three major disorders of fibrinolysis.
Asunto(s)
Antifibrinolíticos/uso terapéutico , Deficiencia del Factor V , Fibrinólisis/genética , Trastornos Hemorrágicos , Inhibidor 1 de Activador Plasminogénico/deficiencia , Ácido Tranexámico/uso terapéutico , alfa 2-Antiplasmina/deficiencia , Plaquetas/metabolismo , Plaquetas/patología , Deficiencia del Factor V/tratamiento farmacológico , Deficiencia del Factor V/genética , Deficiencia del Factor V/metabolismo , Deficiencia del Factor V/patología , Trastornos Hemorrágicos/sangre , Trastornos Hemorrágicos/tratamiento farmacológico , Trastornos Hemorrágicos/genética , Trastornos Hemorrágicos/metabolismo , Trastornos Hemorrágicos/patología , Humanos , Inhibidor 1 de Activador Plasminogénico/genética , Inhibidor 1 de Activador Plasminogénico/metabolismo , Activador de Plasminógeno de Tipo Uroquinasa/genética , Activador de Plasminógeno de Tipo Uroquinasa/metabolismo , alfa 2-Antiplasmina/efectos de los fármacos , alfa 2-Antiplasmina/genéticaRESUMEN
BACKGROUND: Endothelial protein C receptor (EPCR), expressed predominantly on endothelial cells, plays a critical role in the regulation of the coagulation system and also mediates various cytoprotective effects by binding and activating protein C. So far, the role of EPCR has not been studied in systemic sclerosis (SSc). OBJECTIVES: To investigate the potential contribution of EPCR to the development of SSc. METHODS: EPCR expression was examined in skin samples and cultivated dermal microvascular endothelial cells by immunostaining, immunoblotting and/or quantitative reverse-transcription polymerase chain reaction. Fli1, binding to the PROCR promoter, was assessed by chromatin immunoprecipitation. Serum EPCR levels were determined by enzyme-linked immunosorbent assay in 65 patients with SSc and 20 healthy subjects. RESULTS: EPCR expression was decreased in dermal small vessels of SSc lesional skin compared with those of healthy control skin. Transcription factor Fli1, deficiency of which is implicated in SSc vasculopathy, occupied the PROCR promoter, and EPCR expression was suppressed in Fli1 small interfering RNA-treated endothelial cells and dermal small vessels of Fli1(+/-) mice. In patients with SSc, decreased serum EPCR levels were associated with diffuse skin involvement, interstitial lung disease and digital ulcers. Furthermore, serum EPCR levels inversely correlated with plasma levels of plasmin-α2-plasmin inhibitor complex (PIC). Importantly, bosentan significantly reversed circulating EPCR and PIC levels in patients with SSc, and the expression of Fli1 and EPCR in dermal small vessels was elevated in patients treated with bosentan compared with untreated patients. CONCLUSIONS: Endothelial EPCR downregulation due to Fli1 deficiency may contribute to hypercoagulation status leading to tissue fibrosis and impaired peripheral circulation in SSc.
Asunto(s)
Antígenos CD/fisiología , Proteína Proto-Oncogénica c-fli-1/deficiencia , Receptores de Superficie Celular/fisiología , Esclerodermia Sistémica/etiología , Adulto , Anciano , Análisis de Varianza , Animales , Bleomicina/farmacología , Bosentán , Estudios de Casos y Controles , Células Cultivadas , Regulación hacia Abajo/fisiología , Células Endoteliales/metabolismo , Receptor de Proteína C Endotelial , Antagonistas de los Receptores de Endotelina/farmacología , Endotelio Vascular/metabolismo , Ensayo de Inmunoadsorción Enzimática , Femenino , Fibrinolisina/efectos de los fármacos , Humanos , Masculino , Ratones , Microvasos/metabolismo , Persona de Mediana Edad , Esclerodermia Sistémica/sangre , Sulfonamidas/farmacología , Trombofilia/etiología , alfa 2-Antiplasmina/efectos de los fármacosRESUMEN
BACKGROUND AND OBJECTIVES: Neonates undergoing exchange transfusion require <5-day-old red cells suspended in plasma. This study assesses the effect of replacing the saline, adenine, glucose and mannitol (SAGM) of prion reduced (P-Capt) red cells with either methylene blue-treated plasma (MBTFFP) or OctaplasLG to reduce the risk of variant Creutzfelt-Jakob disease transmission. MATERIALS AND METHODS: Twenty leucoreduced red cell units in SAGM were prion reduced on day 1. The SAGM was replaced by MBTFFP (n=10) or OctaplasLG (n=10). The units were irradiated and stored at 4°C for 24 h. A further 20 units were stored for 5 days before being processed as above. Haemolysis (%), potassium, ATP, 2,3-DPG and plasma proteins were measured. RESULTS: Haemolysis remained low (≤0·16%). Following irradiation and storage, red cells in both types of plasma showed similar changes in potassium and ATP concentrations. The 2,3-DPG concentrations were well maintained although lower in red cells in OctaplasLG compared with those in MBTFFP (4·79 vs. 6·83 µmoles/g Hb on day 6). MBTFFP contained lower concentrations of fibrinogen, FV and FVIII. In OctaplasLG, alpha-2-antiplasmin was approximately 0·4 U/ml lower than in MBTFFP. After 24 h at 4°C, free protein S in OctaplasLG fell from 0·82 to 0·57 IU/ml. Other plasma proteins, in both types of plasma, were stable. CONCLUSIONS: Red cells in both types of plasma demonstrated similar storage characteristics. The plasma proteins, except protein S in OctaplasLG, were stable over 24 h at 4°C in both types of plasma, and low FVIII concentrations were noted in the MBTFFP (group O) units used.
Asunto(s)
Conservación de la Sangre/métodos , Detergentes/farmacología , Desinfección/métodos , Transfusión de Eritrocitos , Eritrocitos/metabolismo , Azul de Metileno/farmacología , Intercambio Plasmático/métodos , 2,3-Difosfoglicerato/sangre , Adenosina Trifosfato/sangre , Adenosina Trifosfato/metabolismo , Proteínas Sanguíneas/efectos de los fármacos , Proteínas Sanguíneas/metabolismo , Eritrocitos/citología , Eritrocitos/efectos de los fármacos , Fibrinógeno/efectos de los fármacos , Fibrinógeno/metabolismo , Filtración/métodos , Hemólisis/efectos de los fármacos , Humanos , Recién Nacido , Potasio/sangre , Potasio/metabolismo , Priones , Solventes/farmacología , alfa 2-Antiplasmina/efectos de los fármacos , alfa 2-Antiplasmina/metabolismoRESUMEN
BACKGROUND: Microplasmin is the isolated proteinase domain of plasmin. Administration of microplasmin has been found to neutralize alpha(2)-antiplasmin (alpha(2)-AP) activity, which has been associated with reduced infarct size in various preclinical models of stroke. OBJECTIVES: The goals of this first-in-man study were to investigate the ability of microplasmin to neutralize alpha(2)-AP activity and to monitor its tolerability in healthy male volunteers. METHODS: This Phase I, double-blind, placebo-controlled, ascending-dose study included 10 groups, each containing 6 subjects who were randomized to receive microplasmin or placebo in a 2:1 ratio. The study had 3 parts. In part 1, subjects received a single intravenous bolus of microplasmin 0.1, 0.5, 1, 1.5, or 2 mg/kg or placebo over 15 minutes. In part 2, subjects received a bolus of microplasmin 1 mg/kg or placebo, followed by an infusion of 1, 2, 3, or 4 mg/kg or placebo over 60 minutes. In part 3, subjects, all of whom were aged >55 years, received a bolus of mi-croplasmin 1 mg/kg or placebo, followed by an infusion of 1 mg/kg or placebo. The primary pharmaco-dynamic end point was the change in alpha(2)-AP activity, measured at different time points up to 4 days after dosing using a chromogenic assay. All adverse events were monitored based on spontaneous reports and nondirected questioning at study visits up to the post-study visit 21 days after administration of study drug. RESULTS: The mean (SD) age of subjects in parts 1, 2, and 3 was 30 (8), 30 (8), and 64 (8) years, respectively. All groups receiving microplasmin had a dose-dependent decrease in alpha(2)-AP activity. In part 1, the mean maximal inhibition of alpha(2)-AP was 11.8% (6.0%), 27.7% (4.3%), 53.0% (4.8%), 65.3% (4.3%), and 84.0% (6.0%) after bolus administration of microplasmin 0.1, 0.5, 1, 1.5, and 2 mg/kg, respectively, and 7.4% (6.9%) after administration of placebo. In part 2, the mean maximal inhibition of alpha(2)-AP was 74.6% (11.2%), 95.5% (3.3%), 99.0% (1.0%), and 88.0% (12.5%) after bolus administration of microplasmin 1 mg/kg followed by an infusion of 1, 2, 3, and 4 mg/kg, respectively, compared with 12.9% (6.8%) after administration of placebo. In part 3, the mean maximal inhibition was 69.7% (3.4%) after bolus administration of microplasmin 1 mg/kg followed by an infusion of 1 mg/kg, compared with 8.8% (4.1%) with placebo. One subject in the highest dose group in part 1 (2 mg/kg) and 2 subjects in the highest dose group in part 2 (1 + 4 mg/kg) had an urticarial reaction. All 3 subjects also had a decrease in total hemolytic complement and an increase in complement 5a. CONCLUSIONS: Neutralization of alpha(2)-AP activity by microplasmin was feasible in these healthy male volunteers. The urticarial reactions observed in the highest dose groups were considered dose-limiting adverse events. Further trials are needed to investigate the tolerability of this therapy and whether it is neuroprotective in patients with acute ischemic stroke.
Asunto(s)
Fibrinolisina/farmacología , Fragmentos de Péptidos/farmacología , Urticaria/inducido químicamente , alfa 2-Antiplasmina/efectos de los fármacos , Adulto , Anciano , Relación Dosis-Respuesta a Droga , Método Doble Ciego , Fibrinolisina/administración & dosificación , Fibrinolisina/efectos adversos , Humanos , Inyecciones Intravenosas , Masculino , Persona de Mediana Edad , Fragmentos de Péptidos/administración & dosificación , Fragmentos de Péptidos/efectos adversos , Factores de Tiempo , Adulto Joven , alfa 2-Antiplasmina/metabolismoRESUMEN
PURPOSE: Ulinastatin is well known to inhibit the activity of polymorphonuclear leukocyte elastase (PMNE). The PMNE concentration correlates with the activities of coagulation and fibrinolysis. The purpose of the present study was to investigate the effects of ulinastatin, a protease inhibitor, on coagulation and fibrinolysis in abdominal surgery. METHODS: Thirty patients, aged 40 to 70 years, with American Society of Anesthesiologists (ASA) physical status I or II, scheduled for major abdominal surgery, were enrolled. Anesthesia was induced with midazolam and thiopental, and was maintained with sevoflurane, nitrous oxide in oxygen, and an epidural block. An infusion of ulinastatin, 6000 units x kg(-1) in 30 min, was started 1 h after the start of surgery in the ulinastatin group (15 patients). In the control group (15 patients), no protease inhibitors were infused. White blood cell count; platelet count; prothrombin time; activated partial thromboplastin time; and plasma concentrations of PMNE, antithrombin (AT), fibrin/fibrinogen degradation product (FDP), fibrinogen, plasminogen, plasmin-(alpha2) plasmin inhibitor complex (PIC), and thrombin-antithrombin complex (TAT) were measured before, at the end of, and 12 h after surgery. RESULTS: TAT, PIC, and FDP after surgery were significantly lower in the ulinastatin group than in the control group. AT was decreased in the control group but not in the ulinastatin group, with significant differences between the two groups. CONCLUSION: Ulinastatin could inhibit coagulation and fibrinolysis in abdominal surgery.
Asunto(s)
Abdomen/cirugía , Coagulación Sanguínea/efectos de los fármacos , Fibrinólisis/efectos de los fármacos , Glicoproteínas/farmacología , Inhibidores de Proteasas/farmacología , Inhibidores de Tripsina/farmacología , Antitrombina III/efectos de los fármacos , Antitrombinas/efectos de los fármacos , Femenino , Productos de Degradación de Fibrina-Fibrinógeno/efectos de los fármacos , Fibrinógeno/efectos de los fármacos , Fibrinolisina/efectos de los fármacos , Humanos , Recuento de Leucocitos/estadística & datos numéricos , Elastasa de Leucocito/sangre , Elastasa de Leucocito/efectos de los fármacos , Masculino , Persona de Mediana Edad , Tiempo de Tromboplastina Parcial/estadística & datos numéricos , Péptido Hidrolasas/sangre , Péptido Hidrolasas/efectos de los fármacos , Plasminógeno/efectos de los fármacos , Recuento de Plaquetas/estadística & datos numéricos , Tiempo de Protrombina/estadística & datos numéricos , Sístole , alfa 2-Antiplasmina/efectos de los fármacosRESUMEN
We have recently demonstrated that interleukin (IL)-6 is protective against coagulatory and hemostatic disturbance and subsequent pulmonary hemorrhage induced by bacterial endotoxin, at least partly, via the inhibition of proinflammatory cytokines and chemokines using IL-6-null [IL-6(-/-)] mice and corresponding wild-type mice. Its role in fibrinolytic systems remains undefined, however. The present study elucidated the role of IL-6 in the activity of alpha(2)-plasmin inhibitor, an inhibitor of fibrinolysis, during inflammation induced by intraperitoneal administration of lipopolysaccharide in IL-6(-/-) and wild-type mice. Both IL-6(-/-) and wild-type mice were injected with vehicle or lipopolysaccharide (1 mg/kg). Seventy-two hours later, blood samples were collected and alpha(2)-plasmin inhibitor activity was examined. Lipopolysaccharide challenge induced significant enhancement of alpha(2)-plasmin inhibitor activity as compared with vehicle challenge in wild-type mice, but not in IL-6(-/-) mice. In the presence of lipopolysaccharide, the activity was significantly lower in IL-6(-/-) mice than that in wild-type mice. These results indicate that IL-6 can, at least partly, inhibit the lipopolysaccharide-enhanced fibrinolysis via the enhanced alpha2-plasmin inhibitor activity.
Asunto(s)
Fibrinólisis/efectos de los fármacos , Interleucina-6/inmunología , Lipopolisacáridos/administración & dosificación , Animales , Modelos Animales de Enfermedad , Fibrinólisis/inmunología , Inflamación/inmunología , Inyecciones Intraperitoneales , Interleucina-6/deficiencia , Interleucina-6/farmacología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , alfa 2-Antiplasmina/efectos de los fármacos , alfa 2-Antiplasmina/inmunologíaRESUMEN
BACKGROUND: BB-10153 is an engineered variant of human plasminogen that is activated to plasmin by thrombin. Thrombus-selective induction of reperfusion and prevention of reocclusion have been demonstrated following bolus administration in animal models of thrombosis. OBJECTIVE AND METHODS: The objective of the study was to examine the pharmacokinetics and pharmacodynamics of BB-10153 administered as an intravenous bolus to healthy male human volunteers. Cohorts of four were dosed with BB-10153 (n = 3) or placebo (n = 1). In total, placebo was received by eight volunteers and 0.08, 0.2, 0.6, 1.2, 1.8, 2.4, 3.6 and 4.8 mg kg(-1) BB-10153 by three volunteers each. RESULTS: There was a linear relationship between AUC/Cmax and dose. The half-life of BB-10153 was approximately 3-4 h and all the BB-10153 in the circulation retained the ability to be activated by thrombin. There was a dose-related increase in plasma fibrin D-dimers. Ex vivo plasma clot lysis was observed at doses of 3.6 and 4.8 mg kg(-1), whereas lysis of clots formed from euglobulin-fractionated plasma was first evident at 0.6 mg kg(-1) and activity increased with dose. This activity decreased with time in line with the half-life. BB-10153 had no effect on plasma alpha2-antiplasmin or fibrinogen levels, coagulation assays or bleeding time. An increase in plasminogen was observed as BB-10153 was detected by the enzyme-linked immunosorbent assay (ELISA) for human plasminogen. CONCLUSIONS: BB-10153 was well tolerated and had a 3-4-h plasma half-life. Fibrinolytic activity was demonstrated by dose-related ex vivo clot lysis and in vivo production of fibrin D-dimers. These effects were not accompanied by consumption of alpha2-antiplasmin or fibrinogen.
Asunto(s)
Plasminógeno/farmacocinética , Adolescente , Adulto , Área Bajo la Curva , Método Doble Ciego , Productos de Degradación de Fibrina-Fibrinógeno , Fibrinógeno/efectos de los fármacos , Fibrinólisis , Semivida , Humanos , Masculino , Farmacocinética , Plasminógeno/administración & dosificación , Trombina/metabolismo , alfa 2-Antiplasmina/efectos de los fármacosRESUMEN
OBJECTIVES: Nitric oxide (NO) gas infusion to the oxygenator, as well as heparin-coated bypass circuits, have been reported to attenuate blood activation induced by the interaction with the artificial surfaces of an extracorporeal bypass circuit. Using a mock circulation model, we compared the effect of each and also evaluated the effect of their combination on attenuating bypass-induced blood activation. METHODS: A miniature closed bypass circuit was primed with diluted fresh human blood and perfused for 180 minutes using a centrifugal pump. NO gas (0, 50, or 100 ppm) was infused to the oxygenator sweep gas of either a non-heparin-coated or a heparin-coated circuit. Platelet counts, beta-thromboglobulin, platelet factor 4, complement-3 activation products and granulocyte elastase were measured at 0, 30, 60, 120, and 180 minutes after starting the perfusion. RESULTS: One hundred ppm of NO was statistically equivalent to the heparin-coated circuit for attenuating bypass-induced blood activation, and a combination of the two significantly surpassed the results of either modification alone. Fifty ppm of NO alone provided only a slight attenuation of blood activation as compared with the non-heparin-coated circuit, though the difference was not significant. A combination of 50 ppm NO and the heparin-coated circuit did not significantly enhance the effects of the heparin-coated circuit alone. CONCLUSIONS: The combination of NO gas infusion and heparin-coated circuits appears to be a useful and promising modification for enhancing the attenuation of bypass-induced blood activation, though the optimal dose of NO infusion in terms of effectiveness and adverse effects to the whole body remains to be established.
Asunto(s)
Materiales Biocompatibles Revestidos/uso terapéutico , Circulación Extracorporea/normas , Corazón Auxiliar , Anticoagulantes/uso terapéutico , Antifibrinolíticos/sangre , Antitrombina III/efectos de los fármacos , Biomarcadores/sangre , Coagulación Sanguínea/efectos de los fármacos , Complemento C3a/efectos de los fármacos , Quimioterapia Combinada , Circulación Extracorporea/instrumentación , Fibrinolisina/efectos de los fármacos , Fibrinolíticos/uso terapéutico , Heparina/uso terapéutico , Humanos , Mediadores de Inflamación/sangre , Elastasa de Leucocito/sangre , Elastasa de Leucocito/efectos de los fármacos , Nitratos/sangre , Óxido Nítrico/uso terapéutico , Nitritos/sangre , Péptido Hidrolasas/sangre , Péptido Hidrolasas/efectos de los fármacos , Activación Plaquetaria/efectos de los fármacos , Recuento de Plaquetas , Factor Plaquetario 4/efectos de los fármacos , Factores de Tiempo , Resultado del Tratamiento , alfa 2-Antiplasmina/efectos de los fármacos , beta-Tromboglobulina/efectos de los fármacosRESUMEN
A recombinant human serine protease inhibitor known as Kunitz protease inhibitor (KPI) wild type has functional similarities to the bovine Kunitz inhibitor, aprotinin, and had shown a potential to reduce bleeding in an ovine model of cardiopulmonary bypass (CPB). The aim of this study was to assess KPI-185, a modification of KPI-wild type that differs from KPI-wild type in two amino acid residues and which enhances anti-kallikrein activity in a further double-blind, randomized study in an ovine model of CPB, and to compare with our previous study of KPI-wild type and aprotinin in the same ovine model. Post-operative drain losses and subjective assessment of wound 'dryness' showed no significant differences between KPI-185 and KPI-wild type, despite the significant enhancement of kallikrein inhibition using KPI-185 seen in serial kallikrein inhibition assays. These preliminary findings support the hypothesis that kallikrein inhibition is not the major mechanism by which Kunitz inhibitors such as aprotinin reduce perioperative bleeding.
Asunto(s)
Puente Cardiopulmonar/métodos , Hemostáticos/farmacología , Calicreínas/antagonistas & inhibidores , Ingeniería de Proteínas , Secuencia de Aminoácidos , Sustitución de Aminoácidos , Animales , Antitrombina III/efectos de los fármacos , Aprotinina/administración & dosificación , Aprotinina/farmacología , Pérdida de Sangre Quirúrgica/prevención & control , Puente Cardiopulmonar/efectos adversos , Bovinos , Método Doble Ciego , Evaluación Preclínica de Medicamentos , Hemostasis Quirúrgica/métodos , Hemostáticos/administración & dosificación , Humanos , Modelos Animales , Datos de Secuencia Molecular , Péptido Hidrolasas/sangre , Péptido Hidrolasas/efectos de los fármacos , Estudios Prospectivos , Proteínas Recombinantes/administración & dosificación , Proteínas Recombinantes/genética , Proteínas Recombinantes/farmacología , Inhibidores de Serina Proteinasa/administración & dosificación , Inhibidores de Serina Proteinasa/genética , Inhibidores de Serina Proteinasa/farmacología , Ovinos , alfa 2-Antiplasmina/efectos de los fármacos , alfa 2-Antiplasmina/metabolismoRESUMEN
BACKGROUND: Radiographic contrast agents inhibit fibrinolysis, although by poorly defined pathways. The purpose of this study was to define specific mechanisms by which contrast agents inhibit clot lysis. METHODS AND RESULTS: Diatrizoate (high osmolar ionic agent), ioxaglate (low osmolar ionic), and ioversol (nonionic) were studied in vitro. Diatrizoate inhibited clot lysis by 81.3+/-0.6% vs. control (p<0.001). Ioxaglate inhibited clot lysis by 41.7+/-11.9%, which was of borderline significance (p=0.07). Ioversol did not significantly inhibit clot lysis (14.9+/-11.5% decrease vs. control; p>0.3). Inhibition of fibrinolysis was not explained by the high osmolarities of contrast agents, by their iodine content, or by their effects on the amidolytic activities of t-PA, urokinase, or plasmin. However, plasminogen activation by t-PA, urokinase, or streptokinase was significantly inhibited by contrast agents. Diatrizoate, ioxaglate, and ioversol inhibited plasminogen binding to plasma clots by 51+/-4% (p<0.001), 30.1+/-4% (p<0.01), and 19.4+/-7% (p=0.07), respectively. Plasma clots formed in the presence of contrast agents were resistant to lysis by plasmin. Diatrizoate produced the most potent effect, inhibiting clot lysis by 40+/-5.7% (p<0.03). Contrast agents did not inhibit plasminogen binding to fibrin or plasmin-mediated fibrinolysis if they were added after clot formation. Contrast agents altered clot turbidity, an index of fibrin structure, if present during clot formation, but not if added to preformed clots. Contrast agents did not affect plasminogen activator inhibitor-1 or alpha(2)-antiplasmin function. CONCLUSIONS: Contrast agents inhibit clot lysis by inhibiting plasminogen activation and by disrupting interactions of plasminogen and plasmin with fibrin by altering fibrin structure. Significant variation in antifibrinolytic properties exists between different contrast agents.
Asunto(s)
Antifibrinolíticos/farmacología , Coagulación Sanguínea/efectos de los fármacos , Medios de Contraste/farmacología , Diatrizoato/farmacología , Fibrina/química , Fibrina/efectos de los fármacos , Fibrina/metabolismo , Fibrinolisina/efectos de los fármacos , Fibrinolisina/metabolismo , Humanos , Ácido Yoxáglico/farmacología , Plasminógeno/antagonistas & inhibidores , Plasminógeno/metabolismo , Inhibidor 1 de Activador Plasminogénico/metabolismo , Unión Proteica/efectos de los fármacos , Ácidos Triyodobenzoicos/farmacología , alfa 2-Antiplasmina/efectos de los fármacos , alfa 2-Antiplasmina/metabolismoRESUMEN
alpha2-macroglobulin (alpha2M) is a broad-spectrum proteinase inhibitor and one of the major plasma proteins in humans. Activated phagocytes (especially granulocytes) generate large amounts of oxidants of the HOCI- and chloramine-type that release the mild nonradical, excited (light-emitting) oxidant singlet oxygen ((1)O2). These oxidants have been shown to inactivate several specific serine protease inhibitors in human blood [e.g., alpha1-antitrypsin or alpha2-antiplasmin (plasmin inhibitor)]. The studies reported here demonstrate that nonradical oxidants also inactivate plasmatic alpha2M. The effective dose for 50% inactivation (ED50) of plasmatic alpha2M is similar to that for plasmatic alpha2-antiplasmin. Chloramines are about 1,000-fold more effective than hydrogen peroxide (ED50)=0.75 micromol chloramine T/50 microl plasma). Serine protease-serine protease inhibitor complexes are resistant to oxidants. In contrast, here it is shown that alpha2-macroglobulin, even after binding to serine proteases is sensitive to oxidation, the captured protease is released from the protease/alpha2M complex. This is the first time that oxidative inactivation of a complexed (i.e., bound to a target protease) human protease inhibitor has be shown. The (1)O2 inhibitors methionine, cysteine, cystine, or ascorbate-in contrast to the oxy-radical scavengers mannitol, superoxide dismutase, or catalase-antagonize the chloramine/NaOCl-mediated inactivation of both uncomplexed and complexed alpha2M. Thus, the oxidant involved here is of nonradicalic nature and has reaction characteristics of (1)O2. For the inhibitory function, critical oxidizable methionines or the internal thiol-ester might be targets for (1)O2. Consequently, alpha2M can also be considered a carrier for proteases, since the alpha2M-complexed proteases regain full activity in an oxidative environment. In local areas of inflammation or thrombolysis, activated phagocytes could create microenvironments of uncontrolled protease activity by generation of (1)O2.
Asunto(s)
Oxígeno/farmacología , alfa-Macroglobulinas/efectos de los fármacos , Cloraminas/farmacología , Relación Dosis-Respuesta a Droga , Activación Enzimática/efectos de los fármacos , Humanos , Peróxido de Hidrógeno/farmacología , Inhibidores de Proteasas/metabolismo , Oxígeno Singlete , alfa 2-Antiplasmina/efectos de los fármacos , alfa-Macroglobulinas/antagonistas & inhibidores , alfa-Macroglobulinas/metabolismoRESUMEN
Reptilase, defibrase and ancrod are thrombin-like venom enzymes that cleave fibrinogen to release fibrinopeptide-A and generate fibrin monomers. Although these enzymes decrease fibrinogen levels in vivo, presumably by enhancing fibrinolytic activity, the mechanism has not been identified. In the present study, we analyzed their effects on the inhibitors of fibrinolysis. Plasminogen activator inhibitor-1 (PAI-1) was cleaved at its C-terminus by reptilase and lost its specific activity. Alpha2-antiplasmin (alpha2-AP) was cleaved both at the Pro19-Leu20 peptide bond and at its C-terminus by reptilase, and also lost its specific activity. The apparent second-order rate constants (mol/l per min per Batroxobin unit) were 0.22 for the cleavage of PAI-1 (3.2 micromol/l) and 0.19 for that of alpha2AP (6.4 micromol/l), which were approximately 200-fold lower than that (47.0) for the cleavage of fibrinogen (1.1 micromol/l). Neither defibrase nor ancrod cleaved and inactivated these inhibitors. Only reptilase enhanced euglobulin clot lysis in vitro at high concentration, due probably to PAI-1 inactivation. Since all these three enzymes enhance fibrinolysis similarly during defibrination therapy, the neutralization or inactivation of the inhibitors of fibrinolysis appeared not to represent the main mechanism for the enhancement.
Asunto(s)
Batroxobina/metabolismo , Inhibidor 1 de Activador Plasminogénico/metabolismo , alfa 2-Antiplasmina/metabolismo , Ancrod/farmacología , Batroxobina/farmacología , Coagulación Sanguínea/efectos de los fármacos , Endopeptidasas/farmacología , Fibrinólisis/efectos de los fármacos , Fibrinolíticos/metabolismo , Humanos , Cinética , Peso Molecular , Fragmentos de Péptidos , Seroglobulinas/farmacología , Trombina , Ponzoñas , alfa 2-Antiplasmina/efectos de los fármacosRESUMEN
OBJECTIVE: Heparin coating reduces complement activation on the surface of extracorporeal circuits. In this study we investigated its effect on activation of the contact system in 30 patients undergoing coronary artery bypass grafting with the use of a heparin-coated (Duraflo II, Baxter Healthcare Corp., Edwards Division, Santa Ana, Calif.; n = 15) or an uncoated extracorporeal circuit (n = 15). METHODS: Plasma markers that reflect activation of contact (kallikrein-C1-inhibitor complexes), coagulation (prothrombin fragments F1 + 2), or fibrinolytic (plasmin-alpha 2-antiplasmin complexes) systems were determined before and during the operation. The generation of kallikrein-C1-inhibitor complexes was reduced by 62% (p = 0.06) after the onset of cardiopulmonary bypass and by 43% (p = 0.026) after the cessation of bypass in the group in which a heparin-coated circuit was used compared with the group in which the circuit was uncoated. Generation was reduced by 58% (p = 0.06) when the ratio of kallikrein-C1-inhibitor to prekallikrein after onset of bypass was considered. We detected significant increases in F1 + 2 levels in both groups and increases in plasmin-alpha 2-antiplasmin complexes in the heparin-coated group at cessation of bypass, but no intergroup differences were observed. Thus use of heparin-coated extracorporeal circuits during cardiac operations reduces formation of kallikrein-C1-inhibitor complexes when compared with use of uncoated circuits. The heparin coating is not accompanied by similar reductions in coagulation or fibrinolysis, suggesting that thrombin and plasmin formation during cardiopulmonary bypass occurs mainly independently of the contact system activation.
Asunto(s)
Antifibrinolíticos , Puente Cardiopulmonar/instrumentación , Proteínas Inactivadoras del Complemento 1/efectos de los fármacos , Puente de Arteria Coronaria , Heparina/farmacología , Calicreínas/efectos de los fármacos , Anciano , Coagulación Sanguínea/efectos de los fármacos , Factor XII/efectos de los fármacos , Femenino , Fibrinolisina/efectos de los fármacos , Fibrinólisis/efectos de los fármacos , Heparina/administración & dosificación , Humanos , Masculino , Persona de Mediana Edad , Fragmentos de Péptidos/efectos de los fármacos , Protrombina/efectos de los fármacos , alfa 2-Antiplasmina/efectos de los fármacosRESUMEN
Homozygous type I plasminogen (Plg) deficiency has not been described in human subjects so far. Ligneous conjunctivitis is a rare and unusual form of chronic pseudomembranous conjunctivitis of unknown etiology. Here we report for the first time on homozygous type I Plg deficiency in three unrelated female patients who suffered from ligneous conjunctivitis and additional pseudomembranous lesions of other mucous membranes. The disease is caused by massive fibrin depositions within the "extravascular space" of mucous membranes because of absent clearance by plasmin. Infusions of albumin, fresh frozen plasma, or Lys-plasminogen (Lys-Plg) into two of the three patients revealed normal Plg activation capacity in these patients. The absence of fibrinolytic activity could therefore be shown to be due to Plg deficiency. Similar studies in the third patient have not been completed. In the two patients studied so far, infusions of Lys-Plg resulted in prompt and adequate Plg recovery with a short half-life and high amounts of plasmin-antiplasmin complexes and D-dimer. One patient additionally revealed an inherited partial factor XII deficiency. Functionally, this factor XII deficiency did not interfere with Plg activation. However, there may be a pathway of Plg activation in this patient via the prekallikrein C1-INH system.
Asunto(s)
Plasminógeno/deficiencia , Adolescente , Adulto , Albúminas/farmacología , Antígenos/sangre , Antígenos/efectos de los fármacos , Antitrombina III/análisis , Antitrombina III/efectos de los fármacos , Trastornos de la Coagulación Sanguínea/sangre , Trastornos de la Coagulación Sanguínea/genética , Niño , Preescolar , Conjuntivitis/sangre , Factor XII/análisis , Factor XII/efectos de los fármacos , Deficiencia del Factor XII/sangre , Deficiencia del Factor XII/genética , Salud de la Familia , Femenino , Productos de Degradación de Fibrina-Fibrinógeno/análisis , Productos de Degradación de Fibrina-Fibrinógeno/efectos de los fármacos , Fibrinógeno/análisis , Fibrinógeno/efectos de los fármacos , Fibrinolisina/análisis , Fibrinolisina/efectos de los fármacos , Fibrinólisis/efectos de los fármacos , Hemostasis/efectos de los fármacos , Homocigoto , Humanos , Lactante , Masculino , Persona de Mediana Edad , Membrana Mucosa/patología , Plasma/fisiología , Plasminógeno/análisis , Plasminógeno/farmacología , Precalicreína/análisis , Precalicreína/efectos de los fármacos , Protrombina/análisis , Protrombina/efectos de los fármacos , alfa 2-Antiplasmina/análisis , alfa 2-Antiplasmina/efectos de los fármacosRESUMEN
Hypertonic saline solution (HTS) (7.5 percent sodium chloride [NaCl]) treatment (5 milliliters per kilogram) of rats subjected to uncontrolled hemorrhagic shock (n = 7) caused an initial partial recovery of blood pressure (+38 +/- 5 percent, p<0.05) and cardiac index (+48 +/- 6 percent, p<0.01) followed by increased bleeding (+53 +/- 5 percent versus rats treated with 0.9 percent NaCl, p<0.05), secondary shock (mean arterial pressure [MAP] 23 +/- 7 millimeters of mercury, p<0.01) and decreased survival (-54 +/- 15 minutes versus control, p<0.05). The increased blood loss resulted from: 1, increased vascular pressure and vasodilatation (total peripheral resistance index -27 +/- 5 percent, p<0.05), as initial bleeding occurred when MAP and cardiac index are increased compared with the control group (+88 +/- 10 percent, p<0.05 and +82 +/- 7 percent, p<0.01, respectively) and as the concomitant infusion of angiotensin II, a potent vasoconstrictor, delayed the HTS-induced bleeding (resumed at 60 minutes), and 2, a defect in platelet aggregation reflected by decreased adenosine diphosphate (ADP)-induced maximal aggregation (-79 percent versus rats treated with 0.9 percent NaCl, p<0.05) and increased EC50 of ADP (+159 percent, p<0.05). These hemodynamic and hematologic responses might be mediated at least in part by prostacyclin, a vasodilator and antiplatelet aggregator, as HTS-treated rats markedly elevated the 6-keto-PGF1 alpha per thromboxane B2 ratio (+140 +/- 12 percent, p<0.01) and pretreatment with indomethacin decreased blood loss and improved MAP and survival. These data point out potential untoward hemodynamic and hematologic consequences of HTS treatment in traumatic injury in which control of bleeding cannot be confirmed.
Asunto(s)
Eicosanoides/fisiología , Hemodinámica/efectos de los fármacos , Solución Salina Hipertónica/farmacología , Choque Hemorrágico/fisiopatología , 6-Cetoprostaglandina F1 alfa/sangre , Angiotensina II/farmacología , Animales , Fibrinógeno/efectos de los fármacos , Indometacina/farmacología , Masculino , Tiempo de Tromboplastina Parcial , Agregación Plaquetaria/efectos de los fármacos , Tiempo de Protrombina , Ratas , Ratas Sprague-Dawley , Solución Salina Hipertónica/administración & dosificación , Choque Hemorrágico/sangre , Choque Hemorrágico/tratamiento farmacológico , Tromboxano B2/sangre , alfa 2-Antiplasmina/efectos de los fármacosRESUMEN
We have compared the thrombolytic efficacy of a novel single-chain, recombinant tissue-type plasminogen activator variant, LY210825, containing the second kringle and serine protease domains of native tissue-type plasminogen activator, with anisoylated plasminogen-streptokinase activator complex (APSAC). Male hounds (16-22 kg) were anesthetized, the left circumflex coronary artery was isolated and an electromagnetic flow probe was placed around the artery proximal to the first main branch for the measurement of coronary blood flow. An occlusive thrombus was formed after electrolytic injury of the intima of the coronary artery. After an occlusion period of 1 hr, either LY210825 (n = 8) or APSAC (n = 6) was administered as a single i.v. injection of 0.45 mg/kg. Blood was drawn (3.8% citrate) for determination of plasma fibrinogen, plasminogen and alpha-2 antiplasmin. Time to reperfusion was significantly faster with LY210825 than with APSAC, 20 +/- 2 vs. 54 +/- 8 min, respectively. The incidence of reocclusion was similar for both agents. APSAC produced significant depletion of alpha-2 antiplasmin, plasminogen and circulating fibrinogen, whereas LY210825 caused only slight consumption of plasminogen and only small decreases in fibrinogen. After a single injection of LY210825, thrombolytic concentrations of plasminogen activator were available immediately, whereas there was a significant delay in lytic concentrations of active streptokinase-plasmin complex. Consequently, LY210825 reperfused the coronary artery faster than did APSAC. In addition, LY210825 spared plasma fibrinogen, plasminogen and alpha-2 antiplasmin and therefore, could potentially minimize the risk of bleeding complications.
Asunto(s)
Anistreplasa/uso terapéutico , Trombosis Coronaria/tratamiento farmacológico , Terapia Trombolítica , Activador de Tejido Plasminógeno/uso terapéutico , Animales , Anistreplasa/farmacocinética , Modelos Animales de Enfermedad , Perros , Fibrinógeno/efectos de los fármacos , Fibrinógeno/metabolismo , Hemodinámica/efectos de los fármacos , Masculino , Plasminógeno/efectos de los fármacos , Plasminógeno/metabolismo , Activadores Plasminogénicos/farmacología , Activador de Tejido Plasminógeno/farmacocinética , alfa 2-Antiplasmina/efectos de los fármacos , alfa 2-Antiplasmina/metabolismoRESUMEN
Oren-gedoku-to is a Chinese medicine with hypotensive activity, hemostatic actions and the ability to augment cerebral blood flow. It is therefore expected to be useful in patients with hypertension and cerebrovascular accident (CVA). These effects of Oren-gedoku-to on platelet aggregation and coagulation-fibrinolysis were evaluated. A significant decline in platelet aggregation rate in both healthy control and patient plasma in response to Oren-gedoku-to was found. Maximal platelet aggregation time shortened, however, in healthy controls, but was prolonged in 8 of 20 patients with CVA, in particular those with cerebral infarction.