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1.  Prions in the Urine of Patients with Variant Creutzfeldt–Jakob Disease 
The New England journal of medicine  2014;371(6):530-539.
Prions, the infectious agents responsible for transmissible spongiform encephalopathies, consist mainly of the misfolded prion protein (PrPSc). The unique mechanism of transmission and the appearance of a variant form of Creutzfeldt–Jakob disease, which has been linked to consumption of prion-contaminated cattle meat, have raised concerns about public health. Evidence suggests that variant Creutzfeldt–Jakob disease prions circulate in body fluids from people in whom the disease is silently incubating.
To investigate whether PrPSc can be detected in the urine of patients with variant Creutzfeldt–Jakob disease, we used the protein misfolding cyclic amplification (PMCA) technique to amplify minute quantities of PrPSc, enabling highly sensitive detection of the protein. We analyzed urine samples from several patients with various transmissible spongiform encephalopathies (variant and sporadic Creutzfeldt–Jakob disease and genetic forms of prion disease), patients with other degenerative or nondegenerative neurologic disorders, and healthy persons.
PrPSc was detectable only in the urine of patients with variant Creutzfeldt–Jakob disease and had the typical electrophoretic profile associated with this disease. PrPSc was detected in 13 of 14 urine samples obtained from patients with variant Creutzfeldt–Jakob disease and in none of the 224 urine samples obtained from patients with other neurologic diseases and from healthy controls, resulting in an estimated sensitivity of 92.9% (95% confidence interval [CI], 66.1 to 99.8) and a specificity of 100.0% (95% CI, 98.4 to 100.0). The PrPSc concentration in urine calculated by means of quantitative PMCA was estimated at 1×10−16 g per milliliter, or 3×10−21 mol per milliliter, which extrapolates to approximately 40 to 100 oligomeric particles of PrPSc per milliliter of urine.
Urine samples obtained from patients with variant Creutzfeldt–Jakob disease contained minute quantities of PrPSc. (Funded by the National Institutes of Health and others.)
PMCID: PMC4162740  PMID: 25099577
2.  Transmission Characteristics of Variably Protease-Sensitive Prionopathy 
Emerging Infectious Diseases  2014;20(12):2006-2014.
This disease is transmissible and thus an authentic prion disease.
Variably protease-sensitive prionopathy (VPSPr), a recently identified and seemingly sporadic human prion disease, is distinct from Creutzfeldt-Jakob disease (CJD) but shares features of Gerstmann-Sträussler-Scheinker disease (GSS). However, contrary to exclusively inherited GSS, no prion protein (PrP) gene variations have been detected in VPSPr, suggesting that VPSPr might be the long-sought sporadic form of GSS. The VPSPr atypical features raised the issue of transmissibility, a prototypical property of prion diseases. We inoculated VPSPr brain homogenate into transgenic mice expressing various levels of human PrP (PrPC). On first passage, 54% of challenged mice showed histopathologic lesions, and 34% harbored abnormal PrP similar to that of VPSPr. Surprisingly, no prion disease was detected on second passage. We concluded that VPSPr is transmissible; thus, it is an authentic prion disease. However, we speculate that normal human PrPC is not an efficient conversion substrate (or mouse brain not a favorable environment) and therefore cannot sustain replication beyond the first passage.
PMCID: PMC4257788  PMID: 25418590
transgenic mice; transmissibility; humans; VPSPr; prions and related diseases
3.  Assessing Prion Infectivity of Human Urine in Sporadic Creutzfeldt-Jakob Disease 
Emerging Infectious Diseases  2012;18(1):21-28.
Intracerebral inoculation of transgenic mice failed to demonstrate prion disease transmission.
Prion diseases are neurodegenerative conditions associated with a misfolded and infectious protein, scrapie prion protein (PrPSc). PrPSc propagate prion diseases within and between species and thus pose risks to public health. Prion infectivity or PrPSc presence has been demonstrated in urine of experimentally infected animals, but there are no recent studies of urine from patients with Creutzfeldt-Jakob disease (CJD). We performed bioassays in transgenic mice expressing human PrP to assess prion infectivity in urine from patients affected by a common subtype of sporadic CJD, sCJDMM1. We tested raw urine and 100-fold concentrated and dialyzed urine and assessed the sensitivity of the bioassay along with the effect of concentration and dialysis on prion infectivity. Intracerebral inoculation of transgenic mice with urine from 3 sCJDMM1 patients failed to demonstrate prion disease transmission, indicating that prion infectivity in urine from sCJDMM1 patients is either not present or is <0.38 infectious units/mL.
PMCID: PMC3310101  PMID: 22260924
prions; prions and related diseases; Creutzfeld-Jakob disease; neurodegenerative diseases; transmissible spongiform encephalopathy; infectivity; urine; TSE
4.  Agent strain variation in human prion disease: insights from a molecular and pathological review of the National Institutes of Health series of experimentally transmitted disease 
Brain  2010;133(10):3030-3042.
Six clinico-pathological phenotypes of sporadic Creutzfeldt–Jakob disease have been characterized which correlate at the molecular level with the type (1 or 2) of the abnormal prion protein, PrPTSE, present in the brain and with the genotype of polymorphic (methionine or valine) codon 129 of the prion protein gene. However, to what extent these phenotypes with their corresponding molecular combinations (i.e. MM1, MM2, VV1 etc.) encipher distinct prion strains upon transmission remains uncertain. We studied the PrPTSE type and the prion protein gene in archival brain tissues from the National Institutes of Health series of transmitted Creutzfeldt–Jakob disease and kuru cases, and characterized the molecular and pathological phenotype in the affected non-human primates, including squirrel, spider, capuchin and African green monkeys. We found that the transmission properties of prions from the common sporadic Creutzfeldt–Jakob disease MM1 phenotype are homogeneous and significantly differ from those of sporadic Creutzfeldt–Jakob disease VV2 or MV2 prions. Animals injected with iatrogenic Creutzfeldt–Jakob disease MM1 and genetic Creutzfeldt–Jakob disease MM1 linked to the E200K mutation showed the same phenotypic features as those infected with sporadic Creutzfeldt–Jakob disease MM1 prions, whereas kuru most closely resembled the sporadic Creutzfeldt–Jakob disease VV2 or MV2 prion signature and neuropathology. The findings indicate that two distinct prion strains are linked to the three most common Creutzfeldt–Jakob disease clinico-pathological and molecular subtypes and kuru, and suggest that kuru may have originated from cannibalistic transmission of a sporadic Creutzfeldt–Jakob disease of the VV2 or MV2 subtype.
PMCID: PMC2947429  PMID: 20823086
prion diseases; neuropathology; neurodegenerative disorders; phenotype; strain typing
5.  Molecular biology and pathology of prion strains in sporadic human prion diseases 
Acta neuropathologica  2010;121(1):79-90.
Prion diseases are believed to propagate by the mechanism involving self-perpetuating conformational conversion of the normal form of the prion protein, PrPC, to the misfolded, pathogenic state, PrPSc. One of the most intriguing aspects of these disorders is the phenomenon of prion strains. It is believed that strain properties are fully encoded in distinct conformations of PrPSc. Strains are of practical relevance to human prion diseases, as their diversity may explain the unusual heterogeneity of these disorders. The first insight into the molecular mechanisms underlying heterogeneity of human prion diseases was provided by the observation that two distinct disease phenotypes, and their associated PrPSc conformers, co-distribute with distinct PrP genotypes as determined by the methionine/valine polymorphism at codon 129 of the PrP gene. Subsequent studies identified six possible combinations of the three genotypes (determined by the polymorphic codon 129) and two common PrPSc conformers (named types 1 and 2) as the major determinants of the phenotype in sporadic human prion diseases. This scenario implies that each 129 genotype-PrPSc type combination would be associated with a distinct diseases phenotype and prion strain. However, notable exceptions have been found. For example, two genotype-PrPSc type combinations are linked to the same phenotype and, conversely, the same combination was found to be associated with two distinct phenotypes. Furthermore, in some cases, PrPSc conformers naturally associated with distinct phenotypes appear, upon transmission, to lose their phenotype-determining strain characteristics. Currently it seems safe to assume that typical sporadic prion diseases are associated with at least six distinct prion strains. However the intrinsic characteristics that distinguish at least four of these strains remain to be identified.
PMCID: PMC3077936  PMID: 21058033
Creutzfeldt-Jakob disease; sporadic fatal insomnia; variably protease-sensitive prionopathy; 129 polymorphism; PrPSc type; PrP sequencing
6.  Variably Protease-Sensitive Prionopathy: A New Sporadic Disease of the Prion Protein 
Annals of neurology  2010;68(2):162-172.
The objective of the study is to report 2 new genotypic forms of protease-sensitive prionopathy (PSPr), a novel prion disease described in 2008, in 11 subjects all homozygous for valine at codon 129 of the prion protein (PrP) gene (129VV). The 2 new PSPr forms affect individuals who are either homozygous for methionine (129MM) or heterozygous for methionine/valine (129MV).
Fifteen affected subjects with 129MM, 129MV, and 129VV underwent comparative evaluation at the National Prion Disease Pathology Surveillance Center for clinical, histopathologic, immunohistochemical, genotypical, and PrP characteristics.
Disease duration (between 22 and 45 months) was significantly different in the 129VV and 129MV subjects. Most other phenotypic features along with the PrP electrophoretic profile were similar but distinguishable in the 3 129 genotypes. A major difference laid in the sensitivity to protease digestion of the disease-associated PrP, which was high in 129VV but much lower, or altogether lacking, in 129MV and 129MM. This difference prompted the substitution of the original designation with “variably protease-sensitive prionopathy” (VPSPr). None of the subjects had mutations in the PrP gene coding region.
Because all 3 129 genotypes are involved, and are associated with distinguishable phenotypes, VPSPr becomes the second sporadic prion protein disease with this feature after Creutzfeldt-Jakob disease, originally reported in 1920. However, the characteristics of the abnormal prion protein suggest that VPSPr is different from typical prion diseases, and perhaps more akin to subtypes of Gerstmann-Sträussler-Scheinker disease.
PMCID: PMC3032610  PMID: 20695009
7.  Multiorgan Detection and Characterization of Protease-Resistant Prion Protein in a Case of Variant CJD Examined in the United States 
PLoS ONE  2010;5(1):e8765.
Variant Creutzfeldt–Jakob disease (vCJD) is a prion disease thought to be acquired by the consumption of prion-contaminated beef products. To date, over 200 cases have been identified around the world, but mainly in the United Kingdom. Three cases have been identified in the United States; however, these subjects were likely exposed to prion infection elsewhere. Here we report on the first of these subjects.
Methodology/Principal Findings
Neuropathological and genetic examinations were carried out using standard procedures. We assessed the presence and characteristics of protease-resistant prion protein (PrPres) in brain and 23 other organs and tissues using immunoblots performed directly on total homogenate or following sodium phosphotungstate precipitation to increase PrPres detectability. The brain showed a lack of typical spongiform degeneration and had large plaques, likely stemming from the extensive neuronal loss caused by the long duration (32 months) of the disease. The PrPres found in the brain had the typical characteristics of the PrPres present in vCJD. In addition to the brain and other organs known to be prion positive in vCJD, such as the lymphoreticular system, pituitary and adrenal glands, and gastrointestinal tract, PrPres was also detected for the first time in the dura mater, liver, pancreas, kidney, ovary, uterus, and skin.
Our results indicate that the number of organs affected in vCJD is greater than previously realized and further underscore the risk of iatrogenic transmission in vCJD.
PMCID: PMC2808239  PMID: 20098730
8.  Incidence and spectrum of sporadic Creutzfeldt–Jakob disease variants with mixed phenotype and co-occurrence of PrPSc types: an updated classification 
Acta Neuropathologica  2009;118(5):659-671.
Six subtypes of sporadic Creutzfeldt–Jakob disease with distinctive clinico-pathological features have been identified largely based on two types of the abnormal prion protein, PrPSc, and the methionine (M)/valine (V) polymorphic codon 129 of the prion protein. The existence of affected subjects showing mixed phenotypic features and concurrent PrPSc types has been reported but with inconsistencies among studies in both results and their interpretation. The issue currently complicates diagnosis and classification of cases and also has implications for disease pathogenesis. To explore the issue in depth, we carried out a systematic regional study in a large series of 225 cases. PrPSc types 1 and 2 concurrence was detected in 35% of cases and was higher in MM than in MV or VV subjects. The deposition of either type 1 or 2, when concurrent, was not random and always characterized by the coexistence of phenotypic features previously described in the pure subtypes. PrPSc type 1 accumulation and related pathology predominated in MM and MV cases, while the type 2 phenotype prevailed in VVs. Neuropathological examination best identified the mixed types 1 and 2 features in MMs and most MVs, and also uniquely revealed the co-occurrence of pathological variants sharing PrPSc type 2. In contrast, molecular typing best detected the concurrent PrPSc types in VV subjects and MV cases with kuru plaques. The present data provide an updated disease classification and are of importance for future epidemiologic and transmission studies aimed to identify etiology and extent of strain variation in sporadic Creutzfeldt–Jakob disease.
PMCID: PMC2773124  PMID: 19718500
Prion protein; Brain mapping; Molecular typing; Neurodegeneration; Classification

Results 1-8 (8)