HMOX1 and Alzheimer disease: Significant increases in the levels of HO-1 have been observed in AD brains in association with neurofibrillary tangles and also HO-1 mRNA was found increased in AD neocortex and cerebral vessels; the HO-1 increase also co-localized with senile plaques and glial fibrillary acidic protein-positive astrocytes in AD brains.