Endothelin-1-like immunoreactivity is expressed in human reactive astrocytes.

The expression of endothelin-1-like immunoreactivity in astrocytes of the human brain was investigated by the avidin-biotin-peroxidase complex method in post mortem material. A marked immunoreaction was present in reactive astrocytes around infarcts, lacunes, traumatic injuries, the lesions of progressive multifocal leuco-encephalopathy and in the cerebral cortex and white matter of Alzheimer's disease. The brains of patients who had neither history nor signs of cerebral disease exhibited only occasional immunoreactive astrocytes. A hypothesis is presented that endothelin-1 may be released from reactive astrocytes in many organic diseases of the human brain with considerable pathogenic consequences. It is known from experimental investigations that endothelin-1 may for instance cause severe vasoconstriction resulting in cell injury and that it may act as a growth factor for glial cells.