Publications by authors named "Maria Cramm"

16 Publications

  • Page 1 of 1

Optimization of the Real-Time Quaking-Induced Conversion Assay for Prion Disease Diagnosis.

Front Bioeng Biotechnol 2020 19;8:586890. Epub 2020 Nov 19.

Department of Neurology, German Center for Neurodegenerative Diseases (DZNE), University Medical Center Göttingen, Göttingen, Germany.

The real-time quaking-induced conversion (RT-QuIC) assay is a highly reproducible and robust methodology exhibiting an excellent pre-mortem diagnostic accuracy for prion diseases. However, the protocols might be time-consuming and improvement of the detection technology is needed. In the present study, we investigated the influence of a pre-analytical cerebrospinal fluid (CSF) treatment with proteinase K (PK) on the kinetic of the RT-QuIC signal response. For this purpose, we added PK at different concentrations in RT-QuIC reactions seeded with Creutzfeldt-Jakob disease (sCJD) CSF. We observed that a mild pre-analytical PK treatment of CSF samples resulted in an increased seeding efficiency of the RT-QuIC reaction. Quantitative seeding parameters, such as a higher area under the curve (AUC) value or a shorter lag phase indicated a higher conversion efficiency after treatment. The diagnostic accuracy resulting from 2 μg/ml PK treatment was analyzed in a retrospective study, where we obtained a sensitivity of 89%. Additionally, we analyzed the agreement with the previously established standard RT-QuIC protocol without PK treatment in a prospective study. Here, we found an overall agreement of 94% to 96%. A Cohen's kappa of 0.9036 (95% CI: 0.8114-0.9958) indicates an almost perfect agreement between both protocols. In conclusion, the outcome of our study can be used for a further optimization of the RT-QuIC assay in particular for a reduction of the testing time.
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http://dx.doi.org/10.3389/fbioe.2020.586890DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC7710546PMC
November 2020

Effect of the micro-environment on α-synuclein conversion and implication in seeded conversion assays.

Transl Neurodegener 2020 17;9. Epub 2020 Jan 17.

1Department of Neurology, University Medicine Goettingen and the German Center for Neurodegenerative Diseases (DZNE), Robert-Koch -Straße 40, 37075 Göttingen, Germany.

Background: α-Synuclein is a small soluble protein, whose physiological function in the healthy brain is poorly understood. Intracellular inclusions of α-synuclein, referred to as Lewy bodies (LBs), are pathological hallmarks of α-synucleinopathies, such as Parkinson's disease (PD) or dementia with Lewy bodies (DLB).

Main Body: Understanding of the molecular basis as well as the factors or conditions promoting α-synuclein misfolding and aggregation is an important step towards the comprehension of pathological mechanism of α-synucleinopathies and for the development of efficient therapeutic strategies. Based on the conversion and aggregation mechanism of α-synuclein, novel diagnostic tests, such as protein misfolding seeded conversion assays, e.g. the real-time quaking-induced conversion (RT-QuIC), had been developed. In diagnostics, α-synuclein RT-QuIC exhibits a specificity between 82 and 100% while the sensitivity varies between 70 and 100% among different laboratories. In addition, the α-synuclein RT-QuIC can be used to study the α-synuclein-seeding-characteristics of different α-synucleinopathies and to differentiate between DLB and PD.

Conclusion: The variable diagnostic accuracy of current α-synuclein RT-QuIC occurs due to different protocols, cohorts and material etc.. An impact of micro-environmental factors on the α-synuclein aggregation and conversion process and the occurrence and detection of differential misfolded α-synuclein types or strains might underpin the clinical heterogeneity of α-synucleinopathies
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http://dx.doi.org/10.1186/s40035-019-0181-9DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6966864PMC
January 2020

Seeding variability of different alpha synuclein strains in synucleinopathies.

Ann Neurol 2019 05 27;85(5):691-703. Epub 2019 Mar 27.

Department of Neurology, University Medicine Goettingen and the German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany.

Objectives: Currently, the exact reasons why different α-synucleinopathies exhibit variable pathologies and phenotypes are still unknown. A potential explanation may be the existence of distinctive α-synuclein conformers or strains. Here, we intend to analyze the seeding activity of dementia with Lewy bodies (DLB) and Parkinson's disease (PD) brain-derived α-synuclein seeds by real-time quaking-induced conversion (RT-QuIC) and to investigate the structure and morphology of the α-synuclein aggregates generated by RT-QuIC.

Methods: A misfolded α-synuclein-enriched brain fraction from frontal cortex and substantia nigra pars compacta tissue, isolated by several filtration and centrifugation steps, was subjected to α-synuclein/RT-QuIC analysis. Our study included neuropathologically well-characterized cases with DLB, PD, and controls (Ctrl). Biochemical and morphological analyses of RT-QuIC products were conducted by western blot, dot blot analysis, Raman spectroscopy, atomic force microscopy, and transmission electron microscopy.

Results: Independently from the brain region, we observed different seeding kinetics of α-synuclein in the RT-QuIC in patients with DLB compared to PD and Ctrl. Biochemical characterization of the RT-QuIC product indicated the generation of a proteinase K-resistant and fibrillary α-synuclein species in DLB-seeded reactions, whereas PD and control seeds failed in the conversion of wild-type α-synuclein substrate.

Interpretation: Structural variances of α-synuclein seeding kinetics and products in DLB and PD indicated, for the first time, the existence of different α-synuclein strains in these groups. Therefore, our study contributes to a better understanding of the clinical heterogeneity among α-synucleinopathies, offers an opportunity for a specific diagnosis, and opens new avenues for the future development of strain-specific therapies. Ann Neurol 2019;85:691-703.
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http://dx.doi.org/10.1002/ana.25446DOI Listing
May 2019

Validation and utilization of amended diagnostic criteria in Creutzfeldt-Jakob disease surveillance.

Neurology 2018 07 22;91(4):e331-e338. Epub 2018 Jun 22.

From the National TSE Reference Center (P.H., M.L., T.K., S.G., J.T., M.C., M.S., I.Z.), Department of Neurology, Georg-August University Goettingen; Institute of Neuropathology (M.G., J.M.), University Medical Center Hamburg-Eppendorf, Hamburg; and Institute of Neuropathology (W.S.-S.), Saarland University Medical Center, Germany.

Objective: To validate an amended protocol for clinical diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) including real-time quaking-induced conversion (RT-QuIC) and to observe its use in CJD surveillance.

Methods: In the framework of a prospective epidemiologic study, all neuropathologically confirmed cases with sCJD who received CSF RT-QuIC analysis during diagnostic workup (n = 65) and a control group of individuals without CJD (n = 118) were selected to investigate the accuracy of an amended diagnostic protocol. The patients had been referred to the German National Reference Center for Transmissible Spongiform Encephalopathies. The influence of the amended protocol on incidence figures was evaluated in the context of 3 years of surveillance activity (screened cases using 14-3-3 test n = 18,789, highly suspicious cases of CJD n = 704). Annual incidences were calculated with current criteria and the amended protocol.

Results: The amended protocol showed a sensitivity of 97% and a specificity of 99%. When it was applied to all suspected cases who were referred to the reference center, the assessed incidence of CJD increased from 1.7 to 2.2 per million in 2016.

Conclusion: CJD surveillance remains challenging because information from external health care institutions can be limited. RT-QuIC shows excellent diagnostic accuracy when applied in the clinical setting to symptomatic patients. Data for RT-QuIC alone when applied as a general screening test are not available yet. We propose an amended research protocol that improves early and accurate clinical diagnosis of sCJD during surveillance activities. The use of this protocol will probably lead to a significant increase of the incidence rate.

Classification Of Evidence: This study provides Class III evidence that for patients with suspected sCJD, criteria for clinical diagnosis plus the CSF RT-QuIC accurately identifies patients with sCJD (sensitivity 97%, specificity 99%).
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http://dx.doi.org/10.1212/WNL.0000000000005860DOI Listing
July 2018

Applications of the real-time quaking-induced conversion assay in diagnosis, prion strain-typing, drug pre-screening and other amyloidopathies.

Expert Rev Mol Diagn 2017 10 8;17(10):897-904. Epub 2017 Sep 8.

a Department of Neurology , University Medical Center Göttingen and the German Center for Neurodegenerative Diseases (DZNE) , Göttingen , Germany.

Introduction: The development of in vitro protein misfolding amplification assays for the detection and analysis of abnormally folded proteins, such as proteinase K resistant prion protein (PrP) was a major innovation in the prion field. In prion diseases, these types of assays imitate the pathological conversion of the cellular PrP (PrP) into a proteinase resistant associated conformer or amyloid, called PrP. Areas covered: The most prominent protein misfolding amplification assays are the protein misfolding cyclic amplification (PMCA), which is based on sonication and the real-time quaking-induced conversion (RT-QuIC) technique based on shaking. The more recently established RT-QuIC is fully automatic and enables the monitoring of misfolded protein aggregates in real-time by using a fluorescent dye. Expert commentary: RT-QuIC is a very robust and highly reproducible test system which is applicable in diagnosis, prion strain-typing, drug pre-screening and other amyloidopathies.
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http://dx.doi.org/10.1080/14737159.2017.1368389DOI Listing
October 2017

Altered Ca homeostasis induces Calpain-Cathepsin axis activation in sporadic Creutzfeldt-Jakob disease.

Acta Neuropathol Commun 2017 04 27;5(1):35. Epub 2017 Apr 27.

Department of Neurology, University Medical Center Göttingen, and German Center for Neurodegenerative Diseases (DZNE), Robert Koch Strasse 40, 37075, Göttingen, Germany.

Sporadic Creutzfeldt-Jakob disease (sCJD) is the most prevalent form of human prion disease and it is characterized by the presence of neuronal loss, spongiform degeneration, chronic inflammation and the accumulation of misfolded and pathogenic prion protein (PrP). The molecular mechanisms underlying these alterations are largely unknown, but the presence of intracellular neuronal calcium (Ca) overload, a general feature in models of prion diseases, is suggested to play a key role in prion pathogenesis.Here we describe the presence of massive regulation of Ca responsive genes in sCJD brain tissue, accompanied by two Ca-dependent processes: endoplasmic reticulum stress and the activation of the cysteine proteases Calpains 1/2. Pathogenic Calpain proteins activation in sCJD is linked to the cleavage of their cellular substrates, impaired autophagy and lysosomal damage, which is partially reversed by Calpain inhibition in a cellular prion model. Additionally, Calpain 1 treatment enhances seeding activity of PrP in a prion conversion assay. Neuronal lysosomal impairment caused by Calpain over activation leads to the release of the lysosomal protease Cathepsin S that in sCJD mainly localises in axons, although massive Cathepsin S overexpression is detected in microglial cells. Alterations in Ca homeostasis and activation of Calpain-Cathepsin axis already occur at pre-clinical stages of the disease as detected in a humanized sCJD mouse model.Altogether our work indicates that unbalanced Calpain-Cathepsin activation is a relevant contributor to the pathogenesis of sCJD at multiple molecular levels and a potential target for therapeutic intervention.
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http://dx.doi.org/10.1186/s40478-017-0431-yDOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5408381PMC
April 2017

Validation of α-Synuclein as a CSF Biomarker for Sporadic Creutzfeldt-Jakob Disease.

Mol Neurobiol 2018 03 21;55(3):2249-2257. Epub 2017 Mar 21.

Clinical Dementia Center, Department of Neurology, University Medical Center Göttingen, Robert Koch Stasse 40, 37075, Göttingen, Germany.

The analysis of cerebrospinal fluid (CSF) biomarkers gains importance in the differential diagnosis of prion diseases. However, no single diagnostic tool or combination of them can unequivocally confirm prion disease diagnosis. Electrochemiluminescence (ECL)-based immunoassays have demonstrated to achieve high diagnostic accuracy in a variety of sample types due to their high sensitivity and dynamic range. Quantification of CSF α-synuclein (a-syn) by an in-house ECL-based ELISA assay has been recently reported as an excellent approach for the diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD), the most prevalent form of human prion disease. In the present study, we validated a commercially available ECL-based a-syn ELISA platform as a diagnostic test for correct classification of sCJD cases. CSF a-syn was analysed in 203 sCJD cases with definite diagnosis and in 445 non-CJD cases. We investigated reproducibility and stability of CSF a-syn and made recommendations for its analysis in the sCJD diagnostic workup. A sensitivity of 98% and a specificity of 97% were achieved when using an optimal cut-off of 820 pg/mL a-syn. Moreover, we were able to show a negative correlation between a-syn levels and disease duration suggesting that CSF a-syn may be a good prognostic marker for sCJD patients. The present study validates the use of a-syn as a CSF biomarker of sCJD and establishes the clinical and pre-analytical parameters for its use in differential diagnosis in clinical routine. Additionally, the current test presents some advantages compared to other diagnostic approaches: it is fast, economic, requires minimal amount of CSF and a-syn levels are stable along disease progression.
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http://dx.doi.org/10.1007/s12035-017-0479-5DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC5840235PMC
March 2018

Evaluation of α-synuclein as a novel cerebrospinal fluid biomarker in different forms of prion diseases.

Alzheimers Dement 2017 Jun 18;13(6):710-719. Epub 2016 Nov 18.

Department of Neurology, Clinical Dementia Center, University Medical Center Göttingen, Göttingen, Germany; German Center for Neurodegenerative Diseases (DZNE), Site Göttingen, Germany.

Introduction: Accurate diagnosis of prion diseases and discrimination from alternative dementias gain importance in the clinical routine, but partial overlap in cerebrospinal fluid (CSF) biomarkers impedes absolute discrimination in the differential diagnostic context.

Methods: We established the clinical parameters for prion disease diagnosis for the quantification of CSF α-synuclein in patients with sporadic (n = 234) and genetic (n = 56) prion diseases, in cases with cognitive impairment/dementia or neurodegenerative disease (n = 278), and in the neurologic control group (n = 111).

Results: An optimal cutoff value of 680 pg/mL α-synuclein results in 94% sensitivity and 96% specificity when diagnosing sporadic Creutzfeldt-Jakob disease (CJD). Genetic CJD cases showed increased CSF α-synuclein values. No increased α-synuclein levels were detected in non-CJD cases with rapid progression course.

Discussion: Detection of α-synuclein in the CSF of patients with suspected CJD is a valuable diagnostic test reaching almost full discrimination from non-prion disease cases. These data highlight the utility of CSF α-synuclein quantification in front of classical CSF biomarkers in clinical routine.
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http://dx.doi.org/10.1016/j.jalz.2016.09.013DOI Listing
June 2017

The real-time quaking-induced conversion assay for detection of human prion disease and study of other protein misfolding diseases.

Nat Protoc 2016 Nov 13;11(11):2233-2242. Epub 2016 Oct 13.

Department of Neurology, University Medical Center Göttingen and German Center for Neurodegenerative Diseases (DZNE), Göttingen, Germany.

The development and adaption of in vitro misfolded protein amplification systems has been a major innovation in the detection of abnormally folded prion protein scrapie (PrP) in human brain and cerebrospinal fluid (CSF) samples. Herein, we describe a fast and efficient protein amplification technique, real-time quaking-induced conversion (RT-QuIC), for the detection of a PrP seed in human brain and CSF. In contrast to other in vitro misfolded protein amplification assays-such as protein misfolding cyclic amplification (PMCA)-which are based on sonication, the RT-QuIC technique is based on prion seed-induced misfolding and aggregation of recombinant prion protein substrate, accelerated by alternating cycles of shaking and rest in fluorescence plate readers. A single RT-QuIC assay typically analyzes up to 32 samples in triplicate, using a 96-well-plate format. From sample preparation to analysis of results, the protocol takes ∼87 h to complete. In addition to diagnostics, this technique has substantial generic analytical applications, including drug screening, prion strain discrimination, biohazard screening (e.g., to reduce transmission risk related to prion diseases) and the study of protein misfolding; in addition, it can potentially be used for the investigation of other protein misfolding diseases such as Alzheimer's and Parkinson's disease.
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http://dx.doi.org/10.1038/nprot.2016.120DOI Listing
November 2016

Application of an in vitro-amplification assay as a novel pre-screening test for compounds inhibiting the aggregation of prion protein scrapie.

Sci Rep 2016 07 7;6:28711. Epub 2016 Jul 7.

Department of Neurology, University Medical Center Göttingen and German Center for Neurodegenerative Diseases (DZNE)-Göttingen campus, Göttingen, Germany.

In vitro amplification assays, such as real-time quaking-induced conversion (RT-QuIC) are used to detect aggregation activity of misfolded prion protein (PrP) in brain, cerebrospinal fluid (CSF) and urine samples from patients with a prion disease. We believe that the method also has a much broader application spectrum. In the present study, we applied RT-QuIC as a pre-screening test for substances that potentially inhibit the aggregation process of the cellular PrP (PrP(C)) to proteinase (PK)-resistant PrP(res). We chose doxycycline as the test substance as it has been tested successfully in animal models and proposed in clinical studies as a therapeutic for prion diseases. The RT-QuIC-reaction was seeded with brain tissue or CSF from sCJD patients and doxycycline was then added in different concentrations as well as at different time points. In both experiments, we observed a dose- and time-dependent inhibition of the RT-QuIC seeding response and a decrease of PK resistant PrP(res) when doxycycline was added. In contrast, ampicillin or sucrose had no effect on the RT-QuIC seeding response. Our study is the first to apply RT-QuIC as a pre-screening assay for compounds inhibiting the PrP aggregation in vitro and confirms that doxycycline is an efficient inhibitor of the PrP aggregation process in RT-QuIC analysis.
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http://dx.doi.org/10.1038/srep28711DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4935936PMC
July 2016

Cerebrospinal fluid real-time quaking-induced conversion is a robust and reliable test for sporadic creutzfeldt-jakob disease: An international study.

Ann Neurol 2016 07 1;80(1):160-5. Epub 2016 Jun 1.

National CJD Research & Surveillance Unit, Western General Hospital, University of Edinburgh, Edinburgh, Scotland, United Kingdom.

Real-time quaking-induced conversion (RT-QuIC) has been proposed as a sensitive diagnostic test for sporadic Creutzfeldt-Jakob disease; however, before this assay can be introduced into clinical practice, its reliability and reproducibility need to be demonstrated. Two international ring trials were undertaken in which a set of 25 cerebrospinal fluid samples were analyzed by a total of 11 different centers using a range of recombinant prion protein substrates and instrumentation. The results show almost complete concordance between the centers and demonstrate that RT-QuIC is a suitably reliable and robust technique for clinical practice. Ann Neurol 2016;80:160-165.
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http://dx.doi.org/10.1002/ana.24679DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4982084PMC
July 2016

Identification of new molecular alterations in fatal familial insomnia.

Hum Mol Genet 2016 06 7;25(12):2417-2436. Epub 2016 Apr 7.

Institute of Neuropathology, Service of Pathological Anatomy, Bellvitge University Hospital, University of Barcelona, Bellvitge Biomedical Research Institute (IDIBELL), Hospitalet de Llobregat, and Biomedical Research Center of Neurodegenerative Diseases (CIBERNED) Hospitalet del Llobregat 08907, Spain

Fatal familial insomnia is a rare disease caused by a D178N mutation in combination with methionine (Met) at codon 129 in the mutated allele of PRNP (D178N-129M haplotype). FFI is manifested by sleep disturbances with insomnia, autonomic disorders and spontaneous and evoked myoclonus, among other symptoms. This study describes new neuropathological and biochemical observations in a series of eight patients with FFI. The mediodorsal and anterior nuclei of the thalamus have severe neuronal loss and marked astrocytic gliosis in every case, whereas the entorhinal cortex is variably affected. Spongiform degeneration only occurs in the entorhinal cortex. Synaptic and fine granular proteinase K digestion (PrPres) immunoreactivity is found in the entorhinal cortex but not in the thalamus. Interleukin 6, interleukin 10 receptor alpha subunit, colony stimulating factor 3 receptor and toll-like receptor 7 mRNA expression increases in the thalamus in FFI. PrPc levels are significantly decreased in the thalamus, entorhinal cortex and cerebellum in FFI. This is accompanied by a particular PrPc and PrPres band profile. Altered PrP solubility consistent with significantly reduced PrP levels in the cytoplasmic fraction and increased PrP levels in the insoluble fraction are identified in FFI cases. Amyloid-like deposits are only seen in the entorhinal cortex. The RT-QuIC assay reveals that all the FFI samples of the entorhinal cortex are positive, whereas the thalamus is positive only in three cases and the cerebellum in two cases. The present findings unveil particular neuropathological and neuroinflammatory profiles in FFI and novel characteristics of natural prion protein in FFI, altered PrPres and Scrapie PrP (abnormal and pathogenic PrP) patterns and region-dependent putative capacity of PrP seeding.
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http://dx.doi.org/10.1093/hmg/ddw108DOI Listing
June 2016

Comparative analysis of cerebrospinal fluid biomarkers in the differential diagnosis of neurodegenerative dementia.

Alzheimers Dement 2016 05 21;12(5):577-89. Epub 2015 Dec 21.

Clinical Dementia Center, Department of Neurology, University Medical Center Göttingen, Göttingen, Germany.

Introduction: The analysis of cerebrospinal fluid biomarkers gains importance in clinical routine and is effective in substantiating dementia diagnosis in the differential diagnostic context.

Methods: We evaluated the levels of β-amyloid (Aβ) 42, Aβ40, tau, and P-tau in a large patient population subdivided into prion diseases, tauopathies, synucleinopathies, and controls. Diagnostic test evaluation was assessed by ROC area under the curve analysis.

Results: High tau levels were detected in sporadic Creutzfeldt-Jakob disease (sCJD) and high P-tau levels in Alzheimer's disease (AD) and sCJD. Aβ40 was lower exclusively in prionopathies, but low Aβ42 was detected in AD, sCJD, and Lewy body dementia. When disease groups were stratified according to the underlying proteinopathy, we detected disease-type specificities for all biomarkers. P-tau/tau, Aβ42/40, Aβ42/tau, and Aβ40/tau ratios proved valuable in discriminating disease groups and controls, especially P-tau/tau ratio in the identification of sCJD cases.

Discussion: Combining the biomarker panel allows differentiating between various types of neurodegenerative dementias and contributes to a better understanding of their pathophysiological processes.
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http://dx.doi.org/10.1016/j.jalz.2015.10.009DOI Listing
May 2016

Stability and Reproducibility Underscore Utility of RT-QuIC for Diagnosis of Creutzfeldt-Jakob Disease.

Mol Neurobiol 2016 Apr 1;53(3):1896-1904. Epub 2015 Apr 1.

Department of Neurology, University Medical Center Goettingen and German Center for Neurodegenerative Diseases (DZNE)-site Goettingen, Robert-Koch Str. 40, 37075, Göttingen, Germany.

Real-time quaking-induced conversion (RT-QuIC) allows the amplification of miniscule amounts of scrapie prion protein (PrP(Sc)). Recent studies applied the RT-QuIC methodology to cerebrospinal fluid (CSF) for diagnosing human prion diseases. However, to date, there has not been a formal multi-centre assessment of the reproducibility, validity and stability of RT-QuIC in this context, an indispensable step for establishment as a diagnostic test in clinical practice. In the present study, we analysed CSF from 110 prion disease patients and 400 control patients using the RT-QuIC method under various conditions. In addition, "blinded" ring trials between different participating sites were performed to estimate reproducibility. Using the previously established cut-off of 10,000 relative fluorescence units (rfu), we obtained a sensitivity of 85% and a specificity of 99%. The multi-centre inter-laboratory reproducibility of RT-QuIC revealed a Fleiss' kappa value of 0.83 (95% CI: 0.40-1.00) indicating an almost perfect agreement. Moreover, we investigated the impact of short-term CSF storage at different temperatures, long-term storage, repeated freezing and thawing cycles and the contamination of CSF with blood on the RT-QuIC seeding response. Our data indicated that the PrP(Sc) seed in CSF is stable to any type of storage condition but sensitive to contaminations with blood (>1250 erythrocytes/μL), which results in a false negative RT-QuIC response. Fresh blood-contaminated samples (3 days) can be rescued by removal of erythrocytes. The present study underlines the reproducibility and high stability of RT-QuIC across various CSF storage conditions with a remarkable sensitivity and specificity, suggesting RT-QuIC as an innovative and robust diagnostic method.
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http://dx.doi.org/10.1007/s12035-015-9133-2DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4789202PMC
April 2016

Characteristic CSF prion seeding efficiency in humans with prion diseases.

Mol Neurobiol 2015 Feb 9;51(1):396-405. Epub 2014 May 9.

Department of Neurology, Clinical Dementia Center, University Medical Center Göttingen and German Center for Neurodegenerative Diseases (DZNE) - site Göttingen, Robert-Koch-Str. 40, 37075, Göttingen, Germany.

The development of in vitro amplification systems allows detecting femtomolar amounts of prion protein scrapie (PrP(Sc)) in human cerebrospinal fluid (CSF). We performed a CSF study to determine the effects of prion disease type, codon 129 genotype, PrP(Sc) type, and other disease-related factors on the real-time quaking-induced conversion (RT-QuIC) response. We analyzed times to 10,000 relative fluorescence units, areas under the curve and the signal maximum of RT-QuIC response as seeding parameters of interest. Interestingly, type of prion disease (sporadic vs. genetic) and the PRNP mutation (E200K vs. V210I and FFI), codon 129 genotype, and PrP(Sc) type affected RT-QuIC response. In genetic forms, type of mutation showed the strongest effect on the observed outcome variables. In sporadic CJD, MM1 patients displayed a higher RT-QuIC signal maximum compared to MV1 and VV1. Age and gender were not associated with RT-QuIC signal, but patients with a short disease course showed a higher seeding efficiency of the RT-QuIC response. This study demonstrated that PrP(Sc) characteristics in the CSF of human prion disease patients are associated with disease subtypes and rate of decline as defined by disease duration.
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http://dx.doi.org/10.1007/s12035-014-8709-6DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC4309904PMC
February 2015

Spongiform encephalopathy in siblings with no evidence of protease-resistant prion protein or a mutation in the prion protein gene.

J Neurol 2013 Jul 2;260(7):1871-9. Epub 2013 Apr 2.

National Reference Center for TSE Surveillance, Department of Neurology, University Medical Center Göttingen, Robert-Koch Str. 40, 37075 Göttingen, Germany.

We discuss relevant aspects in two siblings with a neurodegenerative process of unclear aetiology who developed progressive dementia with global aphasia and hyperoral behaviour at the ages of 39 and 46 years and who died 6 and 5 years after disease onset. The cases were reported to the National Reference Center for TSE Surveillance in Göttingen, Germany. Detailed clinical examinations, CSF, blood samples, and copies of the important diagnostic tests (magnetic resonance imaging, electroencephalogram, laboratory tests) were obtained. Further neuropathological and genetic analyses were performed. Cerebral magnetic resonance imaging of both siblings showed prominent changes in signal intensity, especially in the left medial temporal cortex, but also the hippocampal formation. Neuropathological examination revealed spongiform changes, neuronal loss, and astrocytic gliosis, which are typical in Creutzfeldt-Jakob disease. However, no prion protein deposits were detectable by immunohistochemical analysis, Western blot, or PET blot, though abundant tau protein deposits were observed. A mutation in the coding region of the prion protein genes of both siblings was excluded. A detailed search of the literature revealed no other cases with a similar clinical and neuropathological appearance. While the disease aetiology remains unclear, the findings point to a neurodegenerative process and most likely a genetic disease.
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http://dx.doi.org/10.1007/s00415-013-6897-zDOI Listing
July 2013