Prion proteins (PrP) are infectious proteinaceous particles devoid of nucleic acids causing animal and human brain diseases by transmitting a misfolded protein configuration through brain tissue [
9]. The cellular prion protein (PrP
C) is the endogenous and physiological form with a predominant α-helix structure, which can be found on cell membranes of many tissues. In contrast, the prion protein scrapie (PrP
Sc) isoform, which is encoded by the chromosomal prion protein gene (PRNP), is an infectious agent with a much higher proportion of β-sheet structure and a strong tendency to aggregate in form of amyloid fibers and plaques [
10]. PrP
Sc is able to convert normal PrP
c into the infectious PrP
Sc by a conformation change from α-helix to β-sheet structure, which is considered the key event underlying prion diseases [
9]. In this scenario, PrP
Sc acts like a template for the conversion of PrP
c into nascent PrP
Sc constituting a self-propagating vicious cycle [
11]. Prion diseases can be basically caused by three pathogenic mechanisms: 1. sporadic configuration change from PrP
c to PrP
Sc, 2. genetic origin by mutations in the PRNP gene and 3. transfection of PrP
Sc and subsequent conversion of PrP
c by the ingested pathogen. The accumulation and limited proteolysis of PrP
Sc leads to the small molecule PrP27-30 which polymerizes into amyloid potentially capable of inducing neurodegenerative changes in brain tissue [
12]. Prion diseases manifest as sporadic, genetic or infectious disorders with a variety of clinical symptoms and histopathological findings. The most common form is sporadic Creutzfeld-Jakob disease (CJD) with an incidence of nearly 5 per 1 million among individual between 60 and 74 years of age [
13]. CJD is histopathologically characterized by spongiform brain degeneration and astrogliosis with amyloid plaques and positive antibody staining against PrP
Sc in about 10 percent of cases [
14,
15].