RESUMO
Tissue-type plasminogen activator (t-PA) remains the only approved therapy for acute ischemic stroke but has a restrictive treatment time window of 4.5 hr. Prolonged ischemia causes blood-brain barrier (BBB) damage and increases the incidence of hemorrhagic transformation (HT) secondary to reperfusion. In this study, we sought to determine the effect of pinocembrin (PCB; a pleiotropic neuroprotective agent) on t-PA administration-induced BBB damage in a novel rat thromboembolic stroke model. By assessing the leakage of Evans blue into the ischemic hemisphere, we demonstrated that PCB pretreatment 5 min before t-PA administration significantly reduced BBB damage following 2 hr, 4 hr, 6 hr, and even 8 hr ischemia. Consistently, PCB pretreatment significantly decreased t-PA infusion-resulting brain edema and infarction volume and improved the behavioral outcomes following 6 hr ischemia. Mechanistically, PCB pretreatment inhibited the activation of MMP-2 and MMP-9 and degradation of tight junction proteins (TJPs) occludin and claudin-5 in the ischemic hemisphere. Moreover, PCB pretreatment significantly reduced phosphorylation of platelet-derived growth factor receptor α (PDGFRα) as compared with t-PA alone. In an in vitro BBB model, PCB decreased transendothelial permeability upon hypoxia/aglycemia through inhibiting PDGF-CC secretion. In conclusion, we demonstrated that PCB pretreatment shortly before t-PA infusion significantly protects BBB function and improves neurological outcomes following prolonged ischemia beyond the regular 4.5 hr t-PA time window. PCB pretreatment may represent a novel means of increasing the safety and the therapeutic time window of t-PA following ischemic stroke.
Assuntos
Barreira Hematoencefálica/patologia , Embolia/tratamento farmacológico , Flavanonas/uso terapêutico , Fármacos Neuroprotetores/uso terapêutico , Acidente Vascular Cerebral/tratamento farmacológico , Trombose/tratamento farmacológico , Ativador de Plasminogênio Tecidual/uso terapêutico , Animais , Comportamento Animal , Barreira Hematoencefálica/efeitos dos fármacos , Isquemia Encefálica/complicações , Isquemia Encefálica/tratamento farmacológico , Isquemia Encefálica/enzimologia , Isquemia Encefálica/patologia , Modelos Animais de Doenças , Progressão da Doença , Embolia/complicações , Embolia/enzimologia , Embolia/patologia , Flavanonas/líquido cefalorraquidiano , Flavanonas/farmacologia , Humanos , Linfocinas/metabolismo , Masculino , Metaloproteinase 2 da Matriz/metabolismo , Metaloproteinase 9 da Matriz/metabolismo , Fármacos Neuroprotetores/farmacologia , Permeabilidade , Fator de Crescimento Derivado de Plaquetas/metabolismo , Ratos Sprague-Dawley , Receptor alfa de Fator de Crescimento Derivado de Plaquetas/metabolismo , Transdução de Sinais/efeitos dos fármacos , Acidente Vascular Cerebral/complicações , Acidente Vascular Cerebral/enzimologia , Acidente Vascular Cerebral/patologia , Trombose/complicações , Trombose/enzimologia , Trombose/patologia , Proteínas de Junções Íntimas/metabolismo , Fatores de Tempo , Ativador de Plasminogênio Tecidual/administração & dosagem , Ativador de Plasminogênio Tecidual/farmacologiaRESUMO
BACKGROUND/AIMS: Phosphatase and the tensin homolog deleted on chromosome ten (PTEN) has been recognized as a promoter of apoptosis in various tissues and has been shown to be upregulated in circumstances of coronary microembolization (CME). We hypothesized that the upregulation of PTEN correlates with CME-induced myocardial apoptosis. METHODS: Swine CME was induced by an intracoronary injection of inert plastic microspheres (diameter of 42 µm) into the left anterior descending coronary, with or without pretreatment of the PTEN small-interfering RNA (siRNA). Echocardiological measurements, a pathological examination, Terminal-deoxynucleoitidyl Transferase Mediated Nick End Labeling (TUNEL) staining, and Western blotting, were performed to assess their functional, morphological, and molecular effects in CME. RESULTS: PTEN was aberrantly upregulated in cardiomyocytes following CME. Downregulation of PTEN in vivo via siRNA was associated with improved cardiac function and attenuated myocardial apoptosis; concomitantly inhibited the expression of key proapoptotic proteins, such as phosphorylated Bad (p-Bad); cleaved caspase-3; and enhanced the expression of key antiapoptotic proteins, such as phosphorylated protein kinase B (p-Akt). However, there was no difference in the Akt-regulated downstream protein IκB kinases (IKKα, IKKß, and IKKγ) among the sham, CME, and control siRNA groups. CONCLUSION: This study demonstrates, for the first time, that the PTEN/Akt signaling pathway contributes to cardiomyocyte apoptosis. The data generated from this study provide a rationale for the development of PTEN-based therapeutic strategies for CME-induced myocardial injury.
Assuntos
Apoptose , Doença da Artéria Coronariana/enzimologia , Embolia/enzimologia , Miocárdio/enzimologia , PTEN Fosfo-Hidrolase/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Animais , Proteínas Reguladoras de Apoptose/metabolismo , Doença da Artéria Coronariana/genética , Doença da Artéria Coronariana/patologia , Doença da Artéria Coronariana/terapia , Modelos Animais de Doenças , Embolia/genética , Embolia/patologia , Embolia/terapia , Regulação Enzimológica da Expressão Gênica , Miocárdio/patologia , Miócitos Cardíacos/enzimologia , Miócitos Cardíacos/patologia , PTEN Fosfo-Hidrolase/genética , Interferência de RNA , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Terapêutica com RNAi , Transdução de Sinais , Volume Sistólico , Sus scrofa , Regulação para Cima , Função Ventricular EsquerdaRESUMO
An association between phosphodiesterase 4D (PDE4D) gene and risk of stroke has been suggested by deCODE group in an Icelandic population. In the present case-control study we investigated the association of SNP41 (rs12153798) and SNP56 (rs702553) with ischemic stroke and stroke subtypes. Five hundred and sixteen ischemic stroke patients and 513 healthy age and sex matched controls were included in the study. The genotypes were determined by subjecting the PCR products to sequencing. Both the SNPs 56 and 41 associated significantly with stroke [adjusted OR=1.97; 95% CI (1.262-3.082); p=0.003: adjusted OR=5.42; 95% CI (3.45-8.5); p<0.001 respectively]. In addition to this, a novel SNP at position 59736747 T>G was found while sequencing the PCR products including SNP56. This novel SNP was found in patients as well as controls but did not show a significant association with the disease. We found significant association of SNPs 56 and 41 with large artery atherosclerosis, lacunar and cardioembolic stroke. In conclusion PDE4D gene plays a key part in the pathogenesis of ischemic stroke in the South Indian population from Andhra Pradesh.
Assuntos
Nucleotídeo Cíclico Fosfodiesterase do Tipo 3/genética , Polimorfismo de Nucleotídeo Único , Acidente Vascular Cerebral/enzimologia , Acidente Vascular Cerebral/genética , Adulto , Idoso , Aterosclerose/complicações , Aterosclerose/enzimologia , Aterosclerose/genética , Sequência de Bases , Estudos de Casos e Controles , Nucleotídeo Cíclico Fosfodiesterase do Tipo 4 , Embolia/complicações , Embolia/enzimologia , Embolia/genética , Feminino , Frequência do Gene , Estudos de Associação Genética , Cardiopatias/complicações , Cardiopatias/enzimologia , Cardiopatias/genética , Heterozigoto , Homozigoto , Humanos , Índia , Masculino , Pessoa de Meia-Idade , Reação em Cadeia da Polimerase , Acidente Vascular Cerebral/classificação , Acidente Vascular Cerebral/etiologia , Acidente Vascular Cerebral Lacunar/enzimologia , Acidente Vascular Cerebral Lacunar/genéticaRESUMO
BACKGROUND: Embolic events (EE) in infective endocarditis (IE) are caused by fragmentation of vegetations or valvular tissue. Vegetation length is considered to be the most potent predictor of EE, but does not take into account the degree of friability of the vegetation and of the surrounded infected tissue. Matrix metalloproteinases (MMPs) are enzymes involved in degradation of matrix extracellular components and play a role in the pathophysiology of IE. We aimed to determine whether, in addition to the vegetation size, circulating MMPs could provide accurate predictive value of embolism in IE. METHODS: Among 145 patients referred for a native valve IE, we prospectively included 16 patients who experienced EE during antibiotic therapy (new-EE) and 30 patients without new-EE and treated without valvular surgery. A control group of 38 patients with a degenerative valvular heart disease was also included. In addition to clinical, microbiological and echocardiographic assessment, blood MMPs and their inhibitors were assayed in all patients at admission. RESULTS: MMP-9 serum level was significantly higher in patients with new-EE compared to controls (median [interquartile range]; 250 ng/mL [175-455] vs. 111 ng/mL [70-144], respectively; p<0.0001) and patients with no new-EE (250 ng/mL [175-455] vs. 138 ng/mL [95-232]; p<0.01). A higher MMP-9 activity in patients who experienced new-EE was further confirmed by gelatin zymography analysis. Circulating MMP-9 remains a predictor of new-EE after adjustment for vegetation length and other potential confounders. This parameter provided incremental predictive value over vegetation measurements. CONCLUSIONS: MMP-9 serum level is associated with the risk of embolism during IE. This marker might help physicians in the management of the disease, but further prospective studies are need to confirm these preliminary results.
Assuntos
Embolia/etiologia , Metaloproteinases da Matriz/sangue , Adulto , Idoso , Antibacterianos/administração & dosagem , Estudos de Casos e Controles , Embolia/enzimologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Estudos Prospectivos , Fatores de RiscoRESUMO
PURPOSE: To investigate if relationships exist among macrophage infiltration, plasma matrix metalloproteinase (MMP) levels, and the number of emboli generated during endoluminal carotid interventions. METHODS: Carotid endarterectomy specimens excised as intact cylinders (n=27) were subjected to a standardized angioplasty procedure under radiological guidance in an ex vivo pulsatile flow model. Emboli collected in distal filters were counted and sized using microscopy. Preoperative plasma gelatinase activity was determined by gelatin zymography and quantified using image analysis software. Levels of tissue inhibitors of metalloproteinases (TIMP) 1 and 2 were determined by ELISA. Macrophages within postangioplasty plaques were analyzed using immunohistochemical staining for CD68 antigen and graded by a blinded examiner. Statistical analysis was performed using Spearman's rank correlation. RESULTS: The median number of emboli recorded during angioplasty was 104 (interquartile range 33.75-242.5, absolute range 13-1090). Plasma MMP-9 and MMP-2 levels correlated with emboli number (r=0.544 [p=0.003] and r=0.412, [p=0.033], respectively), while TIMP-1 and TIMP-2 levels did not. Macrophage infiltration within the plaques correlated with emboli number (r=0.722, p<0.001) and the plasma MMP-9 level (r=0.489, p=0.010). CONCLUSIONS: These data indicate that plaque macrophage infiltration may play a role in the generation of emboli during endoluminal carotid intervention, possibly via modulation of protease activity.
Assuntos
Angioplastia/efeitos adversos , Artéria Carótida Interna/cirurgia , Embolia/enzimologia , Embolia/etiologia , Macrófagos/fisiologia , Metaloproteinases da Matriz/metabolismo , Artéria Carótida Interna/enzimologia , Estenose das Carótidas/enzimologia , Estenose das Carótidas/cirurgia , Humanos , Técnicas In Vitro , Modelos Cardiovasculares , Fluxo Pulsátil , Inibidores Teciduais de Metaloproteinases/metabolismoRESUMO
Post-ischemic changes in ecto-Ca(2+)-ATPase activity in microglia and the infarcted tissue were studied in a rat model of focal embolic cerebral ischemia using an enzyme histochemical method. Ecto-Ca(2+)-ATPase activity was observed in whole brains in non-operated and sham-operated control animals. In addition, this enzyme activity was determined to be localized in ramified microglia. At 30 min after ischemia, non-microglial ecto-Ca(2+)-ATPase activity in the infarcted tissue slightly decreased and continued to decrease thereafter. The ecto-Ca(2+)-ATPase activity in microglia did not appear changed at this time. The decrease of enzyme activity in the infarcted tissue made it much easier to clearly observe ecto-Ca(2+)-ATPase-positive microglia. The enzyme activity of microglia in the ischemic area began to decrease 2 or 4h after embolization and remarkably decreased, except in the perinuclear cytoplasm, apical parts of the processes, and several parts along the processes, 8h after ischemia. By 12h after onset of embolization, the enzyme activity of microglia and infarcted tissue had almost completely disappeared. Ecto-Ca(2+)-ATPase of microglia is likely to play an important role in the metabolism of extracellular nucleotides in the ischemic area immediately after the onset of embolization by means of ecto-enzymes. Thus, the findings of the present study suggest that microglia might serve to protect the infarcted tissue in the ischemic brain.
Assuntos
Adenosina Trifosfatases/metabolismo , Isquemia Encefálica/enzimologia , Encéfalo/enzimologia , ATPases Transportadoras de Cálcio/metabolismo , Microglia/enzimologia , Animais , Encéfalo/ultraestrutura , Química Encefálica , Isquemia Encefálica/etiologia , Infarto Cerebral/enzimologia , Infarto Cerebral/etiologia , Modelos Animais de Doenças , Embolia/enzimologia , Imuno-Histoquímica , Masculino , Microglia/química , Microglia/ultraestrutura , Neurônios/enzimologia , Ratos , Ratos Wistar , Fatores de TempoRESUMO
Histological and histochemical examinations of canine kidneys 24 hours, 7, 14 and 24 days after embolization of the renal artery with Spongostan showed that during 24 days the resorption and organization of the infarcts in the embolized kidneys and the resorption of Spongostan in the arteries were not yet completed. The intensified reactions to phosphatases, dehydrogenases, and non-specific esterase indicate a prolonged activation of cells playing a role in the resorption and organization of infarcts which may be of significance in the stimulation of immune responses. There were no inflammatory reactions in the embolized arteries.
Assuntos
Embolia/patologia , Rim/irrigação sanguínea , Artéria Renal , Animais , Cães , Embolia/enzimologia , Embolia/etiologia , Esterases/metabolismo , Espuma de Fibrina , Histocitoquímica , Infarto/enzimologia , Infarto/etiologia , Infarto/patologia , Rim/enzimologia , Rim/patologia , Oxirredutases/metabolismo , Monoéster Fosfórico Hidrolases/metabolismo , Fatores de TempoRESUMO
In skeletal muscle isoenzymes of CK were determined by immunprecipitation and chromatography. The activity of CK-MB was between 17 and 47 U/g muscle, corresponding to a quota between 2,1 and 4,2% of the total activity. In sera of patients with muscular dystrophy, polymyositis, hypothyroidism, after arterial embolism, epilepsy, hyperventilation, operations and polytrauma with and without injury to the thorax isoenzymes were measure by immune precipitation- and immune inhibition-test. The percentage of CK-MB in all sera was less than 6% of the total CK-activity (range: 0 to 6%). Only patients in the first day after neurosurgical operations showed a quota till to 6.5% CK-MB. In serum of patients after polytrauma without injury to the thorax the percentage of CK-MB ranged from 0-5.7% while after polytrauma with injury to the thorax and a reasonable suspicion of a damage to the myocardium this quota was between 5.1 and 23.6% of the total activity. CK-BB activity was not detectable in any cases. Therefore a disease or damage of the skeletal muscle is more probable, if the percentage of CK-MB in less than 6%, because in sera of patients with myocardial infarction in the first 48 h after beginning of the symptoms this quota of CK-MB in the most cases in more than 6%.