Efecto de los anticuerpos antifosfolipídicos en la formación y degradación de la malla de fibrina en pacientes con aborto recurrente / Effect of antiphospholipid antibodies on the formation and lysis of fibrin network in patients with recurrent miscarriage

En el presente trabajo se estudió el proceso de formación y disolución de la malla de fibrina y la generación de plasmina en un grupo de pacientes con aborto recurrente (AR) debido a la presencia de anticuerpos antifosfolipídicos (N= 10), mujeres con AR sin el síndrome antifosfolipídico (SAF) (N= 6) y se comparó con un grupo de mujeres sanas (N= 8). Del grupo de pacientes estudiadas con SAF, nueve fueron positivas para anticuerpos anticardiolipina (aCL), cinco para la anti-b2-glicoproteína I (anti-b2GPI), cuatro para ambos anticuerpos, una para anticuerpos antiprotrombina (aPT) y anticoagulante lúpico (AL). El proceso de formación de la fibrina y su disolución fue estudiado por turbidimetría y la generación de plasmina mediante sustrato cromogénico S2251. Las curvas de polimerización de la(s) paciente(s) con AR sin SAF y AL presentaron un incremento en la pendiente y turbidez final, comparado con las del grupo control de mujeres sanas. La velocidad de disolución del coágulo fue mayor en la paciente con AL (21 ± 0) 10-4 DDO/seg y en las AR sin SAF (19,6 ± 5,7) 10-4 DDO/seg, comparado con el grupo control (14,5 ± 2,8) 10-4 DDO/seg. La generación de plasmina estuvo incrementada solamente en las AR sin SAF (85 ± 24%) comparado con 52 ± 3% en el grupo control, p= 0,005. Los cambios observados en el proceso de polimerización y fibrinólisis de la(s) paciente(s) con AR sin SAF y AL pudieran estar relacionados con el incremento en los niveles de fibrinógeno, mientras que los de la generación de plasmina con la entidad mórbida.

The present work was intended to study the process of fibrin formation and lysis and plasmin generation in a group of patients with recurrent miscarriage (RM), due to the presence of antiphospholipid antibodies (N= 10); as well as in women with RM without the antiphospholipid syndrome (APS) (N= 6), compared with those of a group of healthy women (N= 8). In the group of patients with APS, nine were positive for antibodies against cardiolipin (aCL), five for anti-b2-glycoprotein I (anti-b2GPI), four for both antibodies, and one for antibodies against prothrombin (aPT) and lupus anticoagulant (LA). Fibrin formation and lysis was followed by turbidity and plasmin generation using chromogenic substrate S2251. The polymerization curves from RM patients without APS and the LA patient showed an increased slope and maximum turbidity compared to those of the control group. The speed of lysis was higher in the LA patient (21 ± 0) 10-4 DOD/seg and the RM patients without APS (19.6 ± 5.7) 10-4 DDO/seg, compared to that of the control group (14.5 ± 2.8) 10-4 DDO/seg. Plasmin generation increased only in RM patients without APS (85 ± 24%) against the control group (52 ± 3%), p= 0.005. The changes observed in the fibrin polymerization and lysis process of women with RM without APS and LA seem to be related to their higher fibrinogen levels, while the increased plasmin generation was related to the patients´ morbidity.

Fibrosis Hepática: El papel de las metaloproteinasas y de TGF-β / Hepatic fibrosis: Role of matrix Metallopoteases and TGF-β

La fibrosis hepática involucra múltiples eventos celulares y moleculares que inducen un excesivo depósito de proteínas de matriz extracelular que distorsionan la arquitectura del parénquima hepático, cuya etapa final es conocida como cirrosis. El daño proviene de una variedad de causas como abuso de drogas y enfermedades virales, autoinmunes, metabólicas y colestásicas. La degradación de estas proteínas de matriz ocurre predominantemente como una consecuencia de la acción de metalopro teinasas (MMPs) que degradan sustratos colágenos y no colágenos. La degradación de la matriz en el hígado se lleva a cabo principalmente por la acción de cuatro de estas enzimas: MMP-1, MMP-2, MMP-3 y MMP-9. En el sistema fibrinolítico, las MMPs pueden ser activadas a través de un corte proteolítico por acción del activador de plasminógeno tipo urocinasa y un segundo mecanismo de activación es realizado por las mismas MMPs. La regulación para restringir la actividad puede ser a diferentes niveles; en el sistema fibrinolítico el principal regulador es el PAI- 1, molécula que bloquea la conversión de plasminógeno a plasmina y la MMP no puede ser activada. Un segundo nivel de inhibición es posible a través del TIMP, que inhibe la actividad proteolítica aun cuando las MMPs hayan sido activadas vía plasmina. Durante condiciones patológicas la sobreexpresión de estos inhibidores es dirigida por el factor de crecimiento transformante β, el cual en un padecimiento fibrótico actúa como el más importante factor adverso.

Liver fibrosis and cirrhosis involve multiple cellular and molecular events that lead to deposition of an excess of extracellular matrix proteins and increase the distortion of normal liver architecture. Etiologies include chronic viral hepatitis, alcohol abuse and drug toxicity. Degradation of these matrix proteins occurs predominantly as a result of a family of enzymes called metalloproteinases (MMPs) that specifically degrade collagenous and non collagenous substrates. Matrix degradation in the liver is due to the action of at least four of these enzymes: MMP-1, MMP-2, MMP 3 and MMP 9. In the fibrinolytic system, MMPs can be activated through proteolytic cleavage by the action of urokinase plasminogen activator; a second mechanism includes the same metalloproteinases. This activity is regulated at many levels in the fibrinolytic system. The main regulator is the PAI- 1. This molecule blocks the conversion of plasminogen into plasmin, and the MMP cannot be activated. At a second level, the inhibition is possible by binding to inhibitors called TIMP that can inhibit the proteolytic activity even when the MMPs had been previously activated by plasmin. During abnormal conditions, overexpression of these inhibitors is directed by the transforming growth factor-β that in a fibrotic disease acts as an extremely important adverse factor.

Characterization of plasmin(ogen) binding to Streptococcus pneumoniae.

BACKGROUND & OBJECTIVES: The proteolytic activity of plasmin promotes migration of pathogenic bacteria through the human extracellular matrix. The human pathogen Streptococcus pneumoniae binds both human plasminogen and plasmin via the surface displayed alpha-enolase designated Eno. Electron microscopic studies verified the surface exposition of the glycolytic enzyme alpha-enolase and moreover, its ability to reassociate to the cell surface. Carboxyterminal lysine residues of recently described eukaryotic and prokaryotic plasminogen-binding proteins such as SEN of S. pyogenes are involved in interaction with lysine binding sites of kringle domains of plasminogen. In this study, the role of carboxy terminal lysyl residue of eno in plasminogen binding is further analysed. METHODS: Site-directed mutagenesis of eno gene was done using DNA primers with Hind III-restriction enzyme sites for cloning. Purified Eno fusion proteins were separated by SDS-PAGE and human plasminogen binding assay was performed. Radioiodinated ligand binding was done by competitive inhibition assay. RESULTS: Binding assays performed under reduced conditions indicated also a role of the C-terminal lysyl residues of Eno for plasmin(ogen) binding. Binding of pneumococci to radioiodinated plasminogen was competitively inhibited in the presence of plasminogen, kringle 1-3 (LBS 1) and the lysineanalogon epsilon-amino caproic acid indicating the crucial role of lysine-binding sites of plasminogen. However, binding analysis of plasminogen and LBS 1 to wild type Eno and carboxy terminal modified Eno proteins did not reveal any difference in plasminogen-binding activity under native conditions. INTERPRETATION & CONCLUSION: The present results suggested the presence of a further plasminogenbinding motif in Eno. This hypothesis was confirmed by plasminogen-binding activity of reassociated C-terminal modified enolase to the pneumococcal surface and indicated, therefore, the presence of a further binding motif in Eno for plasminogen binding.

Detection of an Ala601Thr Mutation of Plasminogen Gene in 3 out of 36 Korean Patients with Deep Vein Thrombosis

Plasminogen is a key proenzyme in the fibrinolytic and thrombolytic systems. Congenital deficiency of plasminogen and molecular abnormality of plasminogen (dysplasminogenemia) have been reported in association with the thrombotic tendency in human. In dysplasminogenemia, the level of immunoreactive plasminogen is normal, although the functional activity is reduced. Human plasminogen gene spans about 52.5 kb of DNA and consists of 19 exons. Three types of mutations (Ala601Thr, Val355Phe, and Asp676Asn) have been described in dysplasminogenemia. In this study, we measured the plasminogen activity in patients with deep vein thrombosis and analyzed the DNA sequence to detect three point mutations (Ala601Thr, Val355Phe and Asp676Asn) in patients with hypo/dysplasminogenemia. Dysplasminogenemia was identified in 3 (8.3%) of unrelated 36 patients with deep vein thrombosis and the Ala601Thr mutation was detected in all three patients with dysplasminogenemia. In conclusion, dysplasminogenemia is not rare in deep vein thrombosis, which suggests a risk factor for the thrombosis in Korean population.

Study on the mechanism of the annexin II-mediated co-assembly of t-PA and plasminogen / 华中科技大学学报（医学）（英德文版）

In order to further investigate the effect of annexin II (Ann-II) on tissue plasminogen activator (t-PA)-dependent plasminogen (PLG) activation and its interactive mechanism, recombinant native Ann-II bound t-PA, PLG and plasmin with high affinity was examined. The flow cytometric assay showed that the ann-II expression rate was higher in the human umbilical vein endothelial cell (HUVEC) (87.65%) than in the HL-60 cells as controls (35.79%). Two irrelevant proteins, bovine serum albumin (BSA) and equine IgG (EIG) had no effect on the production of plasmin. Ann-II-mediated enhancement of t-PA-dependent PLG activation was inhibited by epsilon-aminocaproic acid or by pretreatment of Ann-II with carboxypeptidase B with the inhibitive rate being 77.8% and 77.0%, respectively. It was revealed that the effect of Ann-II on PLG activation was specific for t-PA. Urokinase didn't bind to Ann-II, demonstrating the role of receptor-related lysine residues on activation of PLG, showing that the Ann-II-PLG interaction was dependent upon carboxyl-terminal lysine residues. These findings suggest that annexin II-mediated co-assembly of t-PA and PLG may promote plasmin generation and play a key role in modulating fibrinolysis on the endothelial surface.

Changes in fibrinolytic activity of blood after prostatectomy.

After prostatectomy, hypofibrinogenemia and bleeding were reported earlier. The objective of present study is to find out, of blood, after prostatectomy. Blood samples of patients posted for operations were studied by following tests before and after operation along with controls. 1. Euglobulin lysis time. 2. Plasminogen assay. 3. Fibrinogen estimation. The results showed clearly that there is decrease in euglobulin lysis time indicating increased plasminogen activator level, increased plasminogen level and decreased fibrinogen level after the operation. This suggests that there is significant increase in fibrinolytic activity of blood after prostatectomy leading to hypofibrinogenemia and clotting defects.

Modulation of staphylokinase-dependent plasminogen activation by mono- and divalent ions

The effect of several ions (Cl-, Na+, K+, Ca2+) on the rate of plasminogen (Pg) activation by recombinant staphylokinase (rSTA) is reported. Both monovalent and divalent ions affect the rate at which Pg is activated by rSTA, in a concentration-dependent manner (range 0-100 mM). In almost all cases, a decrease of the initial velocity of activation was observed. Cl- showed the most striking inhibitory effect at low concentrations (64 percent at 10 mM). However, in the presence of a fibrin surface, this inhibition was attenuated to 38 percent. Surprisingly, 10 mM Ca2+ enhanced the Pg activation rate 21 percent when a polymerized fibrin matrix was present. These data support the idea that ions can modulate the rate of Pg activation through a mechanism that may be associated with changes in the molecular conformation of the zymogen. This effect is strongly dependent on the presence of a fibrin clot

Alfa-manosidasa: su acción sobre antitrombina III, fibrinógeno y plasminógeno / Alfa-manosidase: its action on antithrombin III, fibrinogen and plasminogen

La alfa-manosiadasa (alfa m) es una hidrolasa ácida que se encuentra en los gránulos azurófilos de los leucocitos polimorfonucleares y en menor concentración en los linfocitos. En leucemias agudas no linfoides sus niveles se hallan muy aumentados respecto de los controles normales (p < 0,001). En estos pacientes, se encuentran alteraciones funcionales e inmunológicas de algunas glicoproteínas del sistema plasmático de coagulación y de fibrinólisis, tales como la antitrombina III (AT III), el fibrinógeno o factor I de coagulación (I) y el plasminógeno (Plg). Debido a esto, investigamos la acción de alfa m sobre estas proteínas purificadas, a partir de plasma humano normal, utilizando métodos inmunoelectroforéticos y electroforesis en gel de poliacrilamida con SDS. Se hallan modificaciones importantes en AT III y I y menores en Plg, similares a las obtenidas en los plasmas de los pacientes. Luego, parece que la acción de hidrolasas ácidas es posible in vivo bajo ciertas condiciones patológicas

Lys-plasminógeno / Lys-plasminogen

Los fibrinolíticos (Estreptoquinasa y Uroquinasa) transforman el plasminógeno circulante en plasmina pero actúan poco sobre la fibrina de los trombos. El lys-plasminógeno de origen placentario se fija a la fibrina de los trombos, de modo que al ser activado por los fibrinolíticos promueve la trombólisis y la disolución de los coágulos. con ello se abren nuevas perspectivas a la terapia fibrinolítica en la enfermedad tromboembólica; las obstrucciones arteriales agudas de las extremidades inferiores y en las trombosis coronarias y cerebrales

Comportamiento de la actividad fibrinolítica en el infarto miocárdio agudo / Behaviour of fibrinolycic activity in the acute myocardial infarction

Se estudió el sistema fibrinolítico en 20 pacientes con infarto agudo del miocardio. El estudio fibrinolítico se realizó en cinco etapas diferentes; etapa I, durante las primeiras 24 horas de iniciados los síntomas; etapa II, 24 horas después y las etapas III, IV y V, 48 horas, 72 horas y una semana después. Los resultados fueron: 3, 5, 8, 7 y 6 pacientes mostraron actividad fibrinolítica ligeramente aumentada, en las etapas I, II, III, IV y V respectivamente. La mayoría cursó con fibrinógeno aumentado en todas las etapas. Un mayor número mostró cifras de PDF normales en algunos casos de las etapas III y IV. En las etapas II, III y IV se obtuvo un número de casos con plasminógeno plasmático bajo. En las etapas II y IV un pequeño número de casos mostraron un aumento del tiempo de lisis de la euglobulina. Se comentan los resultados y se afirma la necesidad de interpretar los resultados de laboratorio con valoración integral clínica, inical y evolutiva