Immunohistochemistry with antibodies to hepatocyte growth factor and its receptor protein (c-MET) in human brain tissues.

Hepatocyte growth factor (HGF) is a potent mitogen for mature hepatocytes, and also has multifunctional effects on some other cells in various organs. The human c-Met proto-oncogene product has recently been identified as its high-affinity receptor. We examined HGF-like and c-Met protein-like immunoreactivities in the brains of neurologically normal, lacunar stroke and Alzheimer disease (AD) cases. The HGF antibody stained only round cells in the capillaries and astrocytes in the white matter. Positive staining with the antibody to c-Met protein was seen in microglia, predominantly in the white matter. The possibility of interactions between astrocytes and microglia through HGF and its receptor is suggested.