P2‐111: Expression of Cellular Prion Protein in Alzheimer's and Aging Brains

Although AD and CJD are different diseases, both of them could be classified as protein conformation-based diseases. Misfolding of protein turns α helix into β sheet, which makes protein insoluble and inclined to aggregate, and finally lead to the disease. β-amyloid protein (Aβ) forms the plaques in AD, whereas PrPsc is the protein contribute to CJD. Since the two diseases share similarities on clinical phenotypes and nervous pathologies, many studies are focused on investigating the links between them, exploring the expression of PrPc in AD brains might help to figure out the roles of PrPc in AD and aging. The present study observed the expression of PrPc in AD and normal aging brains, trying to explain the role of PrPc in brain aging. Immunohistochemistry (IHC) staining was applied on 46 cases of brain tissues from Alzheimer’s patients and normal controls of different ages (NC1=middle aged, NC2=aged and NC3=advanced aged). PrPc was found to be positive in frontal lobe and hippocampus of AD and NC2, NC3 groups. Expression of PrPc in frontal lobe was significantly higher in AD group than in NC1 group (P<0.05), whereas in hippocampus, the expression of PrPc was significantly increased in AD brains compared to NC1 and NC2 brains (P<0.05). Furthermore, the IOD ratios of PrPc staining were increased with aging and increased in AD brains compared to all the normal brains (P<0.05).