Do leukocytes play a role in focal ischemia in the brain? An objective review of the literature

Three general lines of evidence have been put forth to support the role of neutrophil recruitment in ischemic cell death. These include (1) the presence of neutrophils within ischemic tissue at the approximate time that substantial cell death occurs, (2) the reduction of ischemia-induced cell loss following neutropenia, and (3) the observation that treatments which prevent neutrophil trafficking can be neuroprotective. Despite the numerous studies that have been conducted, this hypothesis remains controversial, for an objective assessment of the literature reveals great uncertainty for a pathogenic role of neutrophils in the brain damage associated with ischemia. The present chapter briefly summarizes and critically discusses the available data addressing this hypothesis.