No abstract

Summary:Matrix metalloproteinase-9 (MMP-9) activity increases in the brain during the first day after focal ischemia and might be involved in the pathogenesis of tissue damage. We previously showed MMP-9 in the extracellular space of brain parenchyma along with neutrophil recruitment after ischemia. In the present study, we tested whether neutrophils were a direct source of enhanced MMP-9 in the ischemic brain. Neutrophil infiltration was prevented either by injecting an antibody against ICAM-1, which abrogates neutrophil adhesion to the endothelial vessel wall, or by inducing neutropenia. Onehour intraluminal middle cerebral artery occlusion with reperfusion was induced, and studies were performed at 24 hours. Circulating neutrophils expressed 95-kDa MMP-9 and dimers, and infiltrated neutrophils stained positive for MMP-9. The expression of MMP-9 (mainly 95-kDa proform and dimers and, to a lesser extent, 88-kDa form) increased in brain after ischemia/reperfusion. Treatments preventing neutrophil infiltration failed to preclude the ischemia-induced increase in 88-kDa MMP-9 form and gelatinase activity in neurons and blood vessels. However, these treatments prevented the major increase in 95-kDa MMP-9 form and dimers. We conclude that neutrophil infiltration highly contributes to enhanced MMP-9 in the ischemic brain by releasing MMP-9 proform, which might participate in the tissular inflammatory reaction.

Background and Purpose-We sought to assess in 881 consecutive patients with acute ischemic stroke the clinical relevance in regard to functional outcome of the natural antioxidant uric acid measured at hospital admission. Methods-Patients had serum uric acid (mg/dL) measured by standard procedures 18.2Ϯ15.5 hours from clinical onset.At hospital discharge (11.0Ϯ6.0 days), neurological impairment was classified as moderate/severe (Mathew score Յ75; nϭ304) or mild/absent (Mathew score Ͼ75; nϭ577). Demographics, atherosclerotic risk factors, history of organ disease, baseline neurological score, stroke subtype, infarction size, renal function, aspirin use before stroke, stroke therapy, diuretic use, and laboratory markers, including erythrocyte sedimentation rate, were analyzed in both outcome groups with the use of backward logistic regression. Results-Increased uric acid values were found in men, hypertensives, alcohol drinkers, and patients with coronary, pulmonary, or renal diseases. Diabetic patients had lower uric acid levels on admission. Uric acid was directly associated with hematocrit (Pϭ0.001), sodium (Pϭ0.001), creatinine (Pϭ0.001), and triglycerides (Pϭ0.001) and inversely related with nonfasting glucose (Pϭ0.001) levels. Neurological impairment on admission (Pϭ0.001) and final infarction size on CT/MRI (Pϭ0.01) were also inversely associated with uric acid. A logistic regression adjusted for confounders confirmed the following independent (odds ratio, 95% CI) good outcome predictors: age (0.97, 0.96 to 0.99), Mathew score on admission (1.14, 1.12 to 1.17), erythrocyte sedimentation rate (0.98, 0.97 to 0.99), infarction volume (0.98, 0.98 to 0.99), and uric acid (1.12, 1.00 to 1.25). Conclusions-In patients with acute ischemic stroke, there is a 12% increase in the odds of good clinical outcome for each milligram per deciliter increase of serum uric acid. This finding reinforces the relevance of oxidative damage in ischemic stroke.

Adding walnuts to a high-fat meal acutely improves FMD independently of changes in oxidation, inflammation, or ADMA. Both walnuts and olive oil preserve the protective phenotype of endothelial cells.