Análisis comparativo de marcadores de lesión en modelos de isquemia cerebral focal y global en ratas / Injury markers in two models of cerebral ischemia

Introducción. Los indicadores espacio-temporales de lesión son esenciales en el estudio neuropatológico y terapéutico de la isquemia cerebral. Objetivo. Optimizar la técnica de dos modelos de isquemia cerebral (focal y global) y hacer un análisis comparativo de la progresión del daño cerebral, mediante marcadores de neurodegeneración. Materiales y métodos. Se sometieron ratas Wistar a oclusión temporal de la arteria cerebral media o a oclusión de cuatro vasos, y se evaluaron comparativamente el tiempo quirúrgico, la tasa de supervivencia y la recuperación neurológica. Se utilizó trifenilo de tetrazolio para establecer la distribución del infarto y tinción con Fluoro - Jade B ® como marcador de neurodegeneración. La inmunorreacción de la astroglía se evaluó con el anticuerpo contra la proteína acídica fibrilar de la glía ( Glial Fibrillary Acidic Protein, GFAP) y el anticuerpo AT-8 contra la proteína tau hiperfosforilada, 24, 48 y 72 horas después de la isquemia. Resultados. Los modelos de isquemia utilizados requirieron menor tiempo quirúrgico y hubo menor riesgo de muerte, respecto a estudios previos. En el modelo focal, las células positivas con Fluoro - Jade B ® y los astrocitos reactivos, se evidenciaron en corteza e hipocampo a las 24 horas después de la isquemia. En el modelo global, se observó tinción Fluoro - Jade B ® positiva a las 24 horas, aumentando significativamente la reacción de la GFAP a las 72 horas en corteza y a las 48 horas en el hipocampo. La reacción contra la proteína tau hiperfosforilada aumentó progresivamente y fue máxima a las 72 horas en ambos modelos. Conclusiones. Los dos modelos de isquemia cerebral, oclusión temporal de la arteria cerebral media y oclusión de cuatro vasos, fueron optimizados. En estos modelos, los marcadores la tinción Fluoro - Jade B ® y la GFAP permitieron detectar procesos de neurodegeneración 24 horas después de la isquemia, en tanto el marcador de proteína tau hiperfosforilada (AT-8) incrementó progresivamente su reacción hasta las 72 horas, lo cual sugiere la propagación de la excitotoxicidad y la alteración de enzimas implicadas en la fosforilación de proteínas del citoesqueleto.

Introduction: Spatio-temporal indicators of injury are essential for the study of neuropathological processes and for developing therapeutic approaches for stroke. Objective: This study sought to optimize the techniques of two cerebral ischemia models (focal and global) and to comparatively evaluate the progression of brain damage by analyzing markers of neurodegeneration. Materials and methods: Wistar rats were subjected to temporary occlusion of the middle cerebral artery (t-MCAO) or four-vessel occlusion (4-VO), and surgical time, survival rate and neurological recovery were comparatively evaluated. Triphenyl tetrazolium was used to determine the distribution of the infarction, and Fluoro-Jade B was used as a marker of neurodegeneration. Astroglial immunoreactivity was assessed with an anti-glial fibrillary acidic protein (GFAP) antibody, and an anti-AT-8 antibody was used to detect hyperphosphorylated tau protein at 24, 48 and 72 hours post-ischemia. Results: The cerebral ischemia models employed (t-MCAO and 4-VO) required less surgical time and presented less of a death risk compared to those in previous studies. In the focal model, Fluoro-Jadepositive cells and reactive astrocytes were observed in the cerebral cortex and the hippocampus at 24 hours post-ischemia. In the global model, we observed Fluoro-Jade-positive cells at 24 hours, and a significant increase in the reactivity of GFAP was observed at 72 hours in the cortex and at 48 hours in the hippocampus. The immunoreactivity of hyperphosphorylated tau protein increased progressively, reaching a maximum at 72 hours post-ischemia in both models. Conclusions: These results suggest that in the t-MCAO and 4-VO ischemia models, the expression of Fluoro-Jade and GFAP indicates early neurodegeneration at 24 hours post-insult. In contrast, the immunoreactivity of the hyperphosphorylated tau protein marker (AT-8) progressively increases until 72 hours post-insult, which suggests that the progression of excitotoxicity and alteration of enzymes involves the phosphorylation of cytoskeletal proteins.

role of neutrophils and interleukin-8 in acute ischemic stroke

To investigate the crucial role of interleukin 8 [IL-8] as an inflammatory marker in infarct evolution, and course of the disease. The study included 76 patients that were admitted to Haydarpasa Numune Training and Research Hospital, Istanbul, Turkey between September 2001 and June 2002 with an initial diagnosis of acute ischemic stroke, and 28 control subjects with a corresponding mean age. The serum IL-8 levels obtained within 24 hours of the stroke were assessed by the enzyme-linked immunoabsorbent assay method. The patients were divided into 4 groups according to the extent, and localization of the ischemic lesions. Prognosis was evaluated by modified Rankin Scale. In comparison between patients and control groups, there was a statistically significant difference in [p<0.001] IL-8, and neutrophil [net] levels [p=0.000]. The serum IL-8 levels were associated with the extent of the lesion [p<0.01]. Though the serum IL-8 levels were significantly higher in the dependent group [p<0.05], there was no significant difference between net levels, and prognosis [p<0.05]. There was also no significant difference according to age, gender, and etiology between IL-8 and net levels. The high serum IL-8 levels are associated with prognosis. The development of new neuroprotective treatments aimed to prevent neutrophil-mediated-inflammation induced by IL-8 is critical in the treatment of stroke, and prevention of clinical worsening

Avaliaçäo clínica em 123 pacientes com anticorpo antifosfolopídio / Clinical evaluation of 123 patients with antiphospholipid antibodies

A síndrome de anticorpos antifosfolipídios é um distúrbio adquirido das proteínas sangüíneas associadas aos quadros trombóticos, aborto de repetição e trombocitopenia. Uma série de manifestações clínicas diversas tem sido associadas a estes anticorpos e o presente estudo descreve os achados observados no hospital de Base no período de 1993 a 1995 em 123 pacientes com positividade para estes anticorpos do quais em 82 constatou-se um quadro trombótico em 18, abortos de repetição, e em 23 manifestações diversas como no lúpus eritematoso sistêmico, cardiopatias, livedo reticular, tireoidite de Hashimoto, doença de Takayassu e outras. Os anticorpos antifosfolipídios representam uma freqüente condição trombogênica merecendo uma investigação mais sistemática nos quadros trombóticos e de abortos de repetição onde uma causa aparente não é detectada.