gms | German Medical Science

Question: Prion diseases are fatal neurodegenerative diseases caused by the proteinaceous infectious agent, designated PrP^Sc. This misfolded form of the endogenous prion protein (PrP^C) leads to neuronal loss and PrP amyloid deposits in the brain. Creutzfeldt-Jakob disease (CJD) is the most common human prion disease, which can arise either as sporadic, familiar or iatrogenic form. CJD is classified into several subtypes and haplotypes based on PRNP mutations and polymorphic variations at codon 129. Analyses of the conformation and glycosylation pattern of PrP^Sc have been used to discriminate between different strains (Parchi et al., 1996). We have previously shown that luminescent conjugated polymers (LCP) are suitable for the profiling and differentiation between different prion strains in mice (Sigurdson et al., 2007).

Here we want to explore whether the LCPs are useful tools to identify and discriminate between different human prion strains that correlate with onset of the disease and disease progression.

Methods: Frozen sections of cases with confirmed diagnosis of CJD (n=17) and confirmed Morbus Alzheimer (n=3) were stained with 5 different LCPs (pentameric 2-Formamidothiazol-4-acetic acid (FTAA), heptameric FTAA, pentameric 1H-1,2,4-triazol-1-acetic acid (HTAA), heptameric HTAA or polythiophene acetic acid (PTAA)). The binding properties and spectral profile of the stained plaques were analyzed by immunofluorescence microscopy and spectral imaging.

Results: All five LCPs labeled most of the PrP^Sc deposits on frozen section. The heptameric form of FTAA showed specific spectral emission profiles among the cases, and was able to discriminate between different kuru plaques within the same case of CJD. The tested LCPs distinguished prion plaques from beta amyloid and tau fibrils.

Conclusions: Our results show that the majority of the prion strains can be stained by LCPs on frozen material. hFTAA proves to be the most suitable LCP for detecting different human prion strains. So far no obvious relationship between the spectral profiling of different prion strains and clinical history could be detected. Further studies are ongoing to evaluate whether in silico based statistical analyses or other LCPs might show a better correlation with the clinical course of the disease.