[Creutzfeldt-Jakob disease and other human transmissible spongiform encephalopathies. Part II]

Abstract

The second part of this work presents the neuropathological problems of the Creutzfeldt-Jakob disease and basic informations about other human prion diseases. General problems of prion diseases and clinical symptoms of Creutzfeldt-Jakob disease were presented in the first part. Prion diseases are also known as transmissible cerebral amyloidoses (TCA) or transmissible (subacute) spongiform encephalopathies (TSE, SSE). There are following human TSE's: Creutzfeldt-Jakob disease (CJD)--the most frequent TSE, and its new variant (vCJD)--a result of BSE's transmission into human, sometimes treated as a separate disease; also: Gerstmann-Sträussler-Scheinker syndrome (GSS) that may be a variant of familial CJD, kuru--probably a result of sporadic CJD's transmission by cannibalism, and fatal familial insomnia (FFI). Their clinical symptoms (and especially of the CJD), are nonspecific and sometimes variable. The imaging, EEG and other laboratory tests are not specific either. Neuropathological studies are needed but their interpretation may be equivocal. TSE's are characterised by the neurodegenerative process with characteristic spongiosis. However, vacuolisation--similar as in TSE-spongiosis--may occur in some CNS's disorders and in the case of putrescent brain tissue. In some cases of CJD, particularly those of long duration, the neuronal loss and astrocyte proliferation can mask the presence of spongiform changes, especially when vacuoles are not numerous. The only certain diagnostic marker for TSE is PrP(Sc), prion protein, presently believed to be a direct cause for all TSEs (TCAs). The PrP(Sc) has a dominant beta-sheet amyloid structure which makes its detection by immunohistochemical procedure possible only with special pretreatment, e.c.: hydrolytic autoclaving, hydrated autoclaving, incubations: formic acid (or guanidine thiocyanate) pretreatment, also combined pretreatments. These methods are standard diagnostic procedures for transmissible cerebral amyloidoses.