[Prion disease and brain amyloidosis].

Human prion disorders include Kuru, Creutzfeld-Jakob disease (CJD), Gerstman-Straussler-Scheinkler syndrome (GSS), fatal familial insomnia (FFI) and prion protein cerebral amyloid angiopathy (PrPCAA). Prion diseases manifest as infections, genetic and sporadic disorders. In these diseases an abnormal form of the host's protein, prion protein protease-resistant (PrPres), is essential for pathogenic process. Host protein, prion protein protease-sensitive (PrPsen) in humans is encoded by a single copy gene (PRNP) located in the short arm of chromosome 20. To date, 19 different mutations in PRNP have been found that cause inherited prion disease. In these diseases PrPsen undergoes conformational changes involving a shift from alpha-helix to beta-sheet structures. This conversion is important for PrP-amyloidogenesis which occurs to the highest degree in GSS, while it is less frequently seen in other prion diseases. Pathomorphologically, amyloidogenesis in the brain is characterized by formation of PrPres conglomerates, diffuse homogeneous deposits and pleomorphic fibrillar amyloid plaques. The neurotoxic activity of PrPres and its fragments supports the causal relationship between PrPres deposits and neuropathological events in prion diseases. Congo-red and certain sulfated glycans potently inhibit PrPres formation. This raises the potential of therapeutic strategies for the treatment of these diseases.