Glial expression of cytokines in the brains of cerebrovascular disease patients

We examined the immunohistochemical localization of the proinflammatory cytokines tumor necrosis factor-α, lymphotoxin and interferon-γ in 22 autopsy brains of patients with either cerebrovascular disease (CVD) or other neurological diseases as well as 2 non-neurological control brains. These cytokines were coexpressed mostly in the microglia/macrophages and in a few astroglia in the brains with acute cerebral infarction and cerebral hemorrhage. In cases with cerebral infarction, they were observed as early as 33 h after the onset of the illness and persisted for up to 40 days after the onset. In one patient with cerebral hemorrhage who survived for 4 h, the cytokine-immunoreactive glial cells were confined to the margins of the hematoma. In contrast, the cytokine-immunoreactive glia were distributed diffusely in one patient with cerebral hemorrhage who died 12 days after the onset of the illness. Labeling for these cytokines was weak in the glial cells of control brains and those with neurodegenerative diseases, including Alzheimer's disease, Parkinson's disease and multiple system atrophy, in so far as there were no concomitant acute CVD foci. The present results indicate that proinflammatory cytokines are up-regulated in the brains of patients with acute stroke, and suggest an early inflammatory response in human CVD.