ABSTRACT
Patients with defective plasminogen activator inhibitor protein (PAI-1) or with PAI-1 deficiency can experience hemorrhage as a result of a hyperfibrinolysis. In these patients, a normal thrombus forms, but endogenous lysis is unchecked as tissue plasminogen activator is unopposed. Treatment includes anti-fibrinolytic agents, including oral tranexamic acid. Another treatment option is the administration of PAI-1, but this serpin rapidly inactivates itself. We have developed a mutant plasminogen activator inhibitor with a very long half life (VLHL PAI-1, t1/2>700 h). Here we investigate VLHL PAI-1 effects in the blood of PAI-1 deficient mice, as a model of human disease. Using a thrombelastograph, we found that blood clots of PAI-1 knockout mice were lysed much more quickly than wild type mice. Additionally, blood clots had less shear elastic modulus strength than clots of normal animals. VLHL PAI-1 treatment of PAI-1 deficient mice extended or prevented thrombus lysis and increased clot strength in a concentration dependent fashion. These two parameters determine the extent of thrombus growth and regression; thus, further testing is anticipated to confirm the effectiveness of plasminogen activator inhibitor with a very long half life in an in vivo model and we hope that this protein can be effective in human PAI-1 deficiency disorder.
Subject(s)
Plasminogen Activator Inhibitor 1/blood , Plasminogen Activator Inhibitor 1/deficiency , Thrombolytic Therapy , Thrombosis/blood , Animals , Half-Life , Humans , Insecta , Mice , Mice, Inbred C57BL , Mice, Knockout , Plasminogen Activator Inhibitor 1/genetics , Plasminogen Activator Inhibitor 1/therapeutic use , Plasminogen Inactivators/blood , Plasminogen Inactivators/deficiency , Plasminogen Inactivators/therapeutic use , Thrombolytic Therapy/methods , Thrombosis/drug therapyABSTRACT
To investigate the role of tissue plasminogen activator (tPA) in retinal damage, tPA-deficient and wild-type mice were employed. Two different retinal neuron insult models were used in the present study. One is an excitotoxin-treated retinal model, created by direct intravitreal injection of glutamate analogs, NMDA or kainic acid (KA), and the other is an ischemia-reperfusion model induced by transient elevation of intraocular pressure. TdT-dUTP terminal nick-end labeling (TUNEL) method was used to examine the retinal cell nuclear damage. The number of TUNEL-positive cells in ganglion cell layer (GCL) and inner nuclear layer (INL) in tPA-deficient mice after low-, but not high-dose NMDA was significantly less compared to wild type. In contrast, neither intravitreal KA or transient ischemia produced significant difference in retinal damage in tPA vs. wild-type mice. These data show that tPA-deficient mice are resistant to retinal damage by intravitreal injection of NMDA, and indicate that tPA plays a role in the retinal cell damage induced by excitotoxins, especially NMDA.
Subject(s)
Excitatory Amino Acid Agonists/pharmacology , N-Methylaspartate/toxicity , Plasminogen Inactivators/physiology , Retinal Diseases/chemically induced , Animals , Cell Count , DNA Fragmentation , Excitatory Amino Acid Agonists/administration & dosage , Glutamates/administration & dosage , Glutamates/pharmacology , In Situ Nick-End Labeling , Injections , Kainic Acid/administration & dosage , Kainic Acid/pharmacology , Mice , Mice, Inbred C57BL , Mice, Knockout , N-Methylaspartate/administration & dosage , Neurons/drug effects , Plasminogen Inactivators/deficiency , Recombinant Proteins/pharmacology , Reperfusion Injury/pathology , Reperfusion Injury/prevention & control , Retina , Retinal Diseases/pathology , Retinal Ganglion Cells/drug effectsABSTRACT
A possible role of the plasminogen/plasmin or fibrinolytic system in several biological processes has been implied from correlations between fibrinolytic activity and (patho)physiological phenomena. However, such indirect evidence does not allow to definitively establish the biological relevance of this system. Two recently developed technologies, gene targeting and gene transfer, have allowed to more definitively characterize the in vivo role of gene products. The consequences of gain or loss of function of fibrinolytic system components on reproduction, development, health, survival and on hemostasis, thrombosis, neointima formation, tissue remodeling, brain function, malignancy and neovascularization is summarized below. In addition, the possible use of transgenic mice to study gene regulation or to generate monoclonal antibodies against conserved epitopes in the targeted proteins is discussed.
Subject(s)
Fibrinolysin/physiology , Fibrinolysis/genetics , Gene Transfer Techniques , Plasminogen/physiology , Animals , Antibodies, Monoclonal/immunology , Arteriosclerosis/blood , Arteriosclerosis/genetics , Brain/physiology , Enzyme Activation , Gene Expression Regulation , Hemostasis/physiology , Inflammation , Low Density Lipoprotein Receptor-Related Protein-1 , Mice , Mice, Knockout , Mice, Transgenic , Neoplasms, Experimental/blood , Neovascularization, Pathologic/physiopathology , Phenotype , Plasminogen Activators/deficiency , Plasminogen Activators/genetics , Plasminogen Activators/physiology , Plasminogen Inactivators/deficiency , Plasminogen Inactivators/genetics , Plasminogen Inactivators/physiology , Receptors, Immunologic/physiology , Reproduction/physiology , Viscera/pathology , Wound Healing/physiologyABSTRACT
Esta revisión hace referencia a la epidemiología de los estados trombofílicos más importantes, con todas las dificultades para establecer su verdadera prevalencia, la cual se halla influenciada por diversos factores: demográficos, diagnósticos, poblacionales, entre otros. De los pacientes con antecedentes trombóticos recurrentes y/o historia familiar, sólo un 10 por ciento obedece a una trombofilia, existiendo alrededor de un 25 por ciento que posiblemente la presente, pero en donde su etiología no ha podido ser determinada con los métodos hoy disponibles. Las alteraciones fibrinolíticas continúan siendo objeto de discusión, con respecto a la relevancia clínica y a su carácter hereditario (AU)
Subject(s)
Humans , Thrombosis/epidemiology , Thrombosis/classification , Thrombosis/physiopathology , Antithrombin III/deficiency , Protein C/deficiency , Fibrinogens, Abnormal/classification , Fibrinogens, Abnormal/physiology , Thrombophlebitis/etiology , Thrombophlebitis/physiopathology , Plasminogen/deficiency , Plasminogen Inactivators/deficiency , Plasminogen Activators/deficiency , Homocystinuria/physiopathologyABSTRACT
Esta revisión hace referencia a la epidemiología de los estados trombofílicos más importantes, con todas las dificultades para establecer su verdadera prevalencia, la cual se halla influenciada por diversos factores: demográficos, diagnósticos, poblacionales, entre otros. De los pacientes con antecedentes trombóticos recurrentes y/o historia familiar, sólo un 10 por ciento obedece a una trombofilia, existiendo alrededor de un 25 por ciento que posiblemente la presente, pero en donde su etiología no ha podido ser determinada con los métodos hoy disponibles. Las alteraciones fibrinolíticas continúan siendo objeto de discusión, con respecto a la relevancia clínica y a su carácter hereditario
