Stroke risk factors prepare rat brainstem tissues for modified local Shwartzman reaction.

Stroke risk factors such as hypertension, diabetes, advanced age, and genetic predisposition to stroke were demonstrated to prepare rat brainstem tissues for a modified local Shwartzman reaction. A single intracisternal injection of endotoxin provoked the reaction, and affected rats manifested neurologic deficits accompanied by pathologic lesions. Brainstem infarcts developed in only a small proportion of rats without recognized risk factors after intracisternal injection of endotoxin. Thus, stroke risk factors, which are ordinarily regarded as operating through acceleration of atherosclerosis, may predispose to brain ischemia by local effects on brain microcirculation such as those thought to underlie preparation of a tissue for the local Shwartzman reaction.