Comparative evaluation of clinical and cerebrospinal fluid biomarker characteristics in rapidly and non-rapidly progressive Alzheimer's disease.

BACKGROUND: Rapidly progressive forms of Alzheimer's disease (rpAD) are increasingly recognized and may have a prevalence of up to 30% of patients among all patients with Alzheimer's disease (AD). However, insights about risk factors, underlying pathophysiological processes, and clinical characteristics of rpAD remain controversial. This study aimed to gain a comprehensive picture of rpAD and new insights into the clinical manifestation to enable a better interpretation of disease courses in clinical practice as well as in future clinical studies. METHODS: Patients (n = 228) from a prospective observational study on AD were selected and categorized into rpAD (n = 67) and non-rpAD (n = 161) disease groups. Patients were recruited through the German Creutzfeldt-Jakob disease surveillance center and the memory outpatient clinic of the Göttingen University Medical Center, representing diverse phenotypes of the AD population. Biomarkers and clinical presentation were assessed using standardized protocols. A drop of ≥ MMSE 6 points within 12 months defined rapid progressors. RESULTS: Lower CSF Amyloid beta 1-42 concentrations (p = 0.048), lower Amyloid beta 42/40 ratio (p = 0.038), and higher Tau/Amyloid-beta 1-42 ratio, as well as pTau/Amyloid-beta 1-42 ratio (each p = 0.004) were associated with rpAD. Analyzes in a subset of the cohort (rpAD: n = 12; non-rpAD: n = 31) showed higher CSF NfL levels in rpAD (p = 0.024). Clinically, rpAD showed earlier impairment of functional abilities (p < 0.001) and higher scores on the Unified Parkinson's Disease Rating Scale III (p < 0.001), indicating pronounced extrapyramidal motor symptoms. Furthermore, cognitive profiles (adjusted for overall cognitive performance) indicated marked deficits in semantic (p = 0.008) and phonematic (0.023) verbal fluency tests as well as word list learning (p = 0.007) in rpAD compared to non-rpAD. The distribution of APOE genotypes did not differ significantly between groups. CONCLUSIONS: Our results suggest that rpAD is associated with distinct cognitive profiles, earlier occurrence of non-cognitive symptoms, extrapyramidal motoric disturbance, and lower Amyloid-beta 1-42 concentrations in the CSF. The findings may help to characterize a distinct phenotype of rpAD and estimate prognosis based on clinical characteristics and biomarker results. However, an important future goal should be a unified definition for rpAD to enable targeted study designs and better comparability of the results.

Validation of Plasma and CSF Neurofilament Light Chain as an Early Marker for Sporadic Creutzfeldt-Jakob Disease.

Biomarkers are becoming increasingly important for the differential diagnosis of neurodegenerative diseases. Previous observations indicated neurofilament light chain (NfL) as a potential blood-based biomarker for sporadic Creutzfeldt-Jakob disease (sCJD). Here, we investigated the stability, inter-assay/intra-assay variation and the regulation of NfL levels in CSF and plasma in a large cohort of sCJD patients by using a single-molecule array (SIMOA). We defined cutoffs for an accurate diagnosis and measured plasma NfL level in prion-infected mice models at different time points to identify the potential dynamics throughout the disease. Our analyses confirmed CSF and plasma NfL as stable and consistent marker for sCJD. Receiver operating characteristic (ROC) curve analysis showed an AUC of 0.92-0.93 to distinguish sCJD from control groups. Newly defined cutoffs revealed good diagnostic accuracies of CSF and plasma NfL, indicated by a sensitivity of 80-83.5% and a specificity of 87.4-91%. Studies on two humanized prion-infected mice lines (Tg340-PRNP 129MM and Tg361-PRNP 129VV) revealed increased plasma NfL levels in a late pre-clinical or very early clinical stage between 120-150 days post-inoculation. In conclusion, our work supports the potential use of CSF and plasma NfL as a very early biomarker in sCJD diagnostic with good diagnostic accuracies.

Diagnostic accuracy of cerebrospinal fluid biomarkers in genetic prion diseases.

Genetic prion diseases are a rare and diverse group of fatal neurodegenerative disorders caused by pathogenic sequence variations in the prion protein gene, PRNP. Data on CSF biomarkers in patients with genetic prion diseases are limited and conflicting results have been reported for unclear reasons. Here, we aimed to analyse the diagnostic accuracy of CSF biomarkers currently used in prion clinical diagnosis in 302 symptomatic genetic prion disease cases from 11 prion diagnostic centres, encompassing a total of 36 different pathogenic sequence variations within the open reading frame of PRNP. CSF samples were assessed for the surrogate markers of neurodegeneration, 14-3-3 protein (14-3-3), total-tau protein (t-tau) and α-synuclein and for prion seeding activity through the real-time quaking-induced conversion assay. Biomarker results were compared with those obtained in healthy and neurological controls. For the most prevalent PRNP pathogenic sequence variations, biomarker accuracy and associations between biomarkers, demographic and genetic determinants were assessed. Additionally, the prognostic value of biomarkers for predicting total disease duration from symptom onset to death was investigated. High sensitivity of the four biomarkers was detected for genetic Creutzfeldt-Jakob disease associated with the E200K and V210I mutations, but low sensitivity was observed for mutations associated with Gerstmann-Sträussler-Scheinker syndrome and fatal familial insomnia. All biomarkers showed good to excellent specificity using the standard cut-offs often used for sporadic Creutzfeldt-Jakob disease. In genetic prion diseases related to octapeptide repeat insertions, the biomarker sensitivity correlated with the number of repeats. New genetic prion disease-specific cut-offs for 14-3-3, t-tau and α-synuclein were calculated. Disease duration in genetic Creutzfeldt-Jakob disease-E200K, Gerstmann-Sträussler-Scheinker-P102L and fatal familial insomnia was highly dependent on PRNP codon 129 MV polymorphism and was significantly associated with biomarker levels. In a large cohort of genetic prion diseases, the simultaneous analysis of CSF prion disease biomarkers allowed the determination of new mutation-specific cut-offs improving the discrimination of genetic prion disease cases and unveiled genetic prion disease-specific associations with disease duration.

Plasma neurofilament light chain as a biomarker for fatal familial insomnia.

BACKGROUND AND PURPOSE: Fatal familial insomnia is a rare hereditary prion disease associated with the D178N-129M PRNP mutation. Early diagnosis is difficult, because the clinical syndrome may overlap with affective disorders. In addition, most known cerebrospinal fluid biomarkers for prion diseases and magnetic resonance imaging do not show a good diagnostic accuracy for fatal familial insomnia. In this context, data on plasma biomarkers are scarce. METHODS: We analyzed levels of neurofilament light chain, glial fibrillary acidic protein, chitinase-3-like protein 1, calcium-binding protein B, and total tau protein in six serial plasma samples from a patient with fatal familial insomnia. Subsequently, plasma neurofilament light chain was analyzed in n = 25 patients and n = 19 controls. The diagnostic accuracy and associations with disease stage and duration were explored. RESULTS: Among all biomarker candidates in the case study, only neurofilament light chain levels showed a constant evolution and increased over time. They discriminated fatal familial insomnia from controls with an area under the curve of 0.992 (95% confidence interval [CI] = 0.974-1) in the case-control study. Higher concentrations were associated with methionine homozygosity at codon 129 PRNP (p = 0.006), shorter total disease duration (rho = -0.467, p = 0.019, 95% CI = -0.790 to -0.015), and shorter time from sampling to death (rho = -0.467, p = 0.019, 95% CI = -0.773 to -0.019). CONCLUSIONS: Plasma neurofilament light chain may be a valuable minimally invasive diagnostic biomarker for fatal familial insomnia after clinical onset. Most important, stage-related increase and association with disease duration indicate potential as a prognostic marker and as a surrogate marker in clinical trials.

Plasma Lipocalin 2 in Alzheimer's disease: potential utility in the differential diagnosis and relationship with other biomarkers.

BACKGROUND: Lipocalin-2 is a glycoprotein that is involved in various physiological and pathophysiological processes. In the brain, it is expressed in response to vascular and other brain injury, as well as in Alzheimer's disease in reactive microglia and astrocytes. Plasma Lipocalin-2 has been proposed as a biomarker for Alzheimer's disease but available data is scarce and inconsistent. Thus, we evaluated plasma Lipocalin-2 in the context of Alzheimer's disease, differential diagnoses, other biomarkers, and clinical data. METHODS: For this two-center case-control study, we analyzed Lipocalin-2 concentrations in plasma samples from a cohort of n = 407 individuals. The diagnostic groups comprised Alzheimer's disease (n = 74), vascular dementia (n = 28), other important differential diagnoses (n = 221), and healthy controls (n = 84). Main results were validated in an independent cohort with patients with Alzheimer's disease (n = 19), mild cognitive impairment (n = 27), and healthy individuals (n = 28). RESULTS: Plasma Lipocalin-2 was significantly lower in Alzheimer's disease compared to healthy controls (p < 0.001) and all other groups (p < 0.01) except for mixed dementia (vascular and Alzheimer's pathologic changes). Areas under the curve from receiver operation characteristics for the discrimination of Alzheimer's disease and healthy controls were 0.783 (95%CI: 0.712-0.855) in the study cohort and 0.766 (95%CI: 0.627-0.905) in the validation cohort. The area under the curve for Alzheimer's disease versus vascular dementia was 0.778 (95%CI: 0.667-0.890) in the study cohort. In Alzheimer's disease patients, plasma Lipocalin2 did not show significant correlation with cerebrospinal fluid biomarkers of neurodegeneration and AD-related pathology (total-tau, phosphorylated tau protein, and beta-amyloid 1-42), cognitive status (Mini Mental Status Examination scores), APOE genotype, or presence of white matter hyperintensities. Interestingly, Lipocalin 2 was lower in patients with rapid disease course compared to patients with non-rapidly progressive Alzheimer's disease (p = 0.013). CONCLUSIONS: Plasma Lipocalin-2 has potential as a diagnostic biomarker for Alzheimer's disease and seems to be independent from currently employed biomarkers.

Detection of Cerebrospinal Fluid Neurofilament Light Chain as a Marker for Alpha-Synucleinopathies.

Alpha-synucleinopathies, such as Parkinson's disease (PD), dementia with Lewy bodies (DLB), and multiple system atrophy (MSA), are a class of neurodegenerative diseases. A diagnosis may be challenging because clinical symptoms partially overlap, and there is currently no reliable diagnostic test available. Therefore, we aimed to identify a suitable marker protein in cerebrospinal fluid (CSF) to distinguish either between different types of alpha-synucleinopathies or between alpha-synucleinopathies and controls. In this study, the regulation of different marker protein candidates, such as alpha-synuclein (a-Syn), neurofilament light chain (NfL), glial fibrillary acidic protein (GFAP), and total tau (tau) in different types of alpha-synucleinopathies, had been analyzed by using an ultrasensitive test system called single-molecule array (SIMOA). Interestingly, we observed that CSF-NfL was significantly elevated in patients with DLB and MSA compared to patients with PD or control donors. To differentiate between groups, receiver operating characteristic (ROC) curve analysis resulted in a very good diagnostic accuracy as indicated by the area under the curve (AUC) values of 0.87-0.92 for CSF-NfL. Furthermore, we observed that GFAP and tau were slightly increased either in DLB or MSA, while a-Syn levels remained unregulated. Our study suggests NfL as a promising marker to discriminate between different types of alpha-synucleinopathies or between DLB/MSA and controls.

Heterogeneity and Cancer-Related Features in Lymphangioleiomyomatosis Cells and Tissue.

Lymphangioleiomyomatosis (LAM) is a rare, low-grade metastasizing disease characterized by cystic lung destruction. LAM can exhibit extensive heterogeneity at the molecular, cellular, and tissue levels. However, the molecular similarities and differences among LAM cells and tissue, and their connection to cancer features are not fully understood. By integrating complementary gene and protein LAM signatures, and single-cell and bulk tissue transcriptome profiles, we show sources of disease heterogeneity, and how they correspond to cancer molecular portraits. Subsets of LAM diseased cells differ with respect to gene expression profiles related to hormones, metabolism, proliferation, and stemness. Phenotypic diseased cell differences are identified by evaluating lumican (LUM) proteoglycan and YB1 transcription factor expression in LAM lung lesions. The RUNX1 and IRF1 transcription factors are predicted to regulate LAM cell signatures, and both regulators are expressed in LAM lung lesions, with differences between spindle-like and epithelioid LAM cells. The cancer single-cell transcriptome profiles most similar to those of LAM cells include a breast cancer mesenchymal cell model and lines derived from pleural mesotheliomas. Heterogeneity is also found in LAM lung tissue, where it is mainly determined by immune system factors. Variable expression of the multifunctional innate immunity protein LCN2 is linked to disease heterogeneity. This protein is found to be more abundant in blood plasma from LAM patients than from healthy women. IMPLICATIONS: This study identifies LAM molecular and cellular features, master regulators, cancer similarities, and potential causes of disease heterogeneity.

Diagnostic and prognostic value of plasma neurofilament light and total-tau in sporadic Creutzfeldt-Jakob disease.

BACKGROUND: Blood neurofilament light (Nfl) and total-tau (t-tau) have been described to be increased in several neurological conditions, including prion diseases and other neurodegenerative dementias. Here, we aim to determine the accuracy of plasma Nfl and t-tau in the differential diagnosis of neurodegenerative dementias and their potential value as prognostic markers of disease severity. METHODS: Plasma Nfl and t-tau were measured in healthy controls (HC, n = 70), non-neurodegenerative neurological disease with (NND-Dem, n = 17) and without dementia syndrome (NND, n = 26), Alzheimer's disease (AD, n = 44), Creutzfeldt-Jakob disease (CJD, n = 83), dementia with Lewy bodies/Parkinson's disease with dementia (DLB/PDD, n = 35), frontotemporal dementia (FTD, n = 12), and vascular dementia (VaD, n = 22). Biomarker diagnostic accuracies and cutoff points for the diagnosis of CJD were calculated, and associations between Nfl and t-tau concentrations with other fluid biomarkers, demographic, genetic, and clinical data in CJD cases were assessed. Additionally, the value of Nfl and t-tau predicting disease survival in CJD was evaluated. RESULTS: Among diagnostic groups, highest plasma Nfl and t-tau concentrations were detected in CJD (fold changes of 38 and 18, respectively, compared to HC). Elevated t-tau was able to differentiate CJD from all other groups, whereas elevated Nfl concentrations were also detected in NND-Dem, AD, DLB/PDD, FTD, and VaD compared to HC. Both biomarkers discriminated CJD from non-CJD dementias with an AUC of 0.93. In CJD, plasma t-tau, but not Nfl, was associated with PRNP codon 129 genotype and CJD subtype. Positive correlations were observed between plasma Nfl and t-tau concentrations, as well as between plasma and CSF concentrations of both biomarkers (p < 0.001). Nfl was increased in rapidly progressive AD (rpAD) compared to slow progressive AD (spAD) and associated to Mini-Mental State Examination results. However, Nfl displayed higher accuracy than t-tau discriminating CJD from rpAD and spAD. Finally, plasma t-tau, but not plasma Nfl, was significantly associated with disease duration, offering a moderate survival prediction capacity. CONCLUSIONS: Plasma Nfl and t-tau are useful complementary biomarkers for the differential diagnosis of CJD. Additionally, plasma t-tau emerges as a potential prognostic marker of disease duration.

TREM2 expression in the brain and biological fluids in prion diseases.

Triggering receptor expressed on myeloid cells 2 (TREM2) is an innate immune cell surface receptor that regulates microglial function and is involved in the pathophysiology of several neurodegenerative diseases. Its soluble form (sTREM2) results from shedding of the TREM2 ectodomain. The role of TREM2 in prion diseases, a group of rapidly progressive dementias remains to be elucidated. In the present study, we analysed the expression of TREM2 and its main sheddase ADAM10 in the brain of sporadic Creutzfeldt-Jakob disease (sCJD) patients and evaluated the role of CSF and plasma sTREM2 as a potential diagnostic marker of prion disease. Our data indicate that, compared to controls, TREM2 is increased in sCJD patient brains at the mRNA and protein levels in a regional and subtype dependent fashion, and expressed in a subpopulation of microglia. In contrast, ADAM10 is increased at the protein, but not the mRNA level, with a restricted neuronal expression. Elevated CSF sTREM2 is found in sCJD, genetic CJD with mutations E200K and V210I in the prion protein gene (PRNP), and iatrogenic CJD, as compared to healthy controls (HC) (AUC = 0.78-0.90) and neurological controls (AUC = 0.73-0.85), while CSF sTREM2 is unchanged in fatal familial insomnia. sTREM2 in the CSF of cases with Alzheimer's disease, and multiple sclerosis was not significantly altered in our series. CSF sTREM2 concentrations in sCJD are PRNP codon 129 and subtype-related, correlate with CSF 14-3-3 positivity, total-tau and YKL-40, and increase with disease progression. In plasma, sTREM2 is increased in sCJD compared with HC (AUC = 0.80), displaying positive correlations with plasma total-tau, neurofilament light, and YKL-40. We conclude that comparative study of TREM2 in brain and biological fluids of prion diseases reveals TREM2 to be altered in human prion diseases with a potential value in target engagement, patient stratification, and disease monitoring.

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

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.

A prognostic model for overall survival in sporadic Creutzfeldt-Jakob disease.

INTRODUCTION: We developed a prognostic model for overall survival after diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) using data from a German surveillance study. METHODS: We included 1226 sCJD cases (median age 66 years, range 19-89 years; 56.8% women with information on age, sex, codon 129 genotype, 14-3-3 in the cerebrospinal fluid (CSF), and CSF tau concentrations. The prognostic accuracy for overall survival was measured by the c statistics of multivariable Cox proportional hazard models. A score chart was derived to predict 6-month survival and median survival time. RESULTS: A model containing age, sex, codon 129 genotype, and CSF tau (with two-way interactions) was selected as the model with the highest c statistic (0.686, 95% confidence interval: 0.665-0.707) in a cross-validation approach. DISCUSSION: We developed the first prognostic model for overall survival of sCJD patients based on readily available information only. The developed score chart serves as a hands-on prediction tool for clinical practice.

A new tetra-plex fluorimetric assay for the quantification of cerebrospinal fluid ß-amyloid42, total-tau, phospho-tau and α-synuclein in the differential diagnosis of neurodegenerative dementia.

BACKGROUND: Differential diagnosis of neurodegenerative dementia is currently supported by biomarkers including cerebrospinal fluid (CSF) tests. Among them, CSF total-tau (t-tau), phosphorylated tau (p-tau) and ß-amyloid42 (Aß42) are considered core biomarkers of neurodegeneration. In the present work, we hypothesize that simultaneous assessment of these biomarkers together with CSF α-synuclein (α-syn) will significantly improve the differential diagnostic of Alzheimer's disease and other dementias. To that aim, we characterized the analytical and clinical performance of a new tetra-plex immunoassay that simultaneously quantifies CSF Aß42, t-tau, p-tau and α-syn in the differential diagnosis of neurodegenerative dementia. METHODS: Biomarkers' concentrations were measured in neurological controls (n = 38), Alzheimer's disease (n = 35), Creutzfeldt-Jakob disease (n = 37), vascular dementia (n = 28), dementia with Lewy bodies/Parkinson's disease dementia (n = 27) and frontotemporal dementia (n = 34) using the new tetra-plex assay and established single-plex assays. Biomarker's performance was evaluated and diagnostic accuracy in the discrimination of diagnostic groups was determined using partial least squares discriminant analysis. RESULTS: The tetra-plex assay presented accuracies similar to individual single-plex assays with acceptable analytical performance. Significant correlations were observed between tetra-plex and single-plex assays. Using partial least squares discriminant analysis, Alzheimer's disease and Creutzfeldt-Jakob disease were well differentiated, reaching high accuracies in the discrimination from the rest of diagnostic groups. CONCLUSIONS: The new tetra-plex assay coupled with multivariate analytical approaches becomes a valuable asset for the differential diagnosis of neurodegenerative dementia and related applications.

Cerebrospinal fluid lipocalin 2 as a novel biomarker for the differential diagnosis of vascular dementia.

The clinical diagnosis of vascular dementia (VaD) is based on imaging criteria, and specific biochemical markers are not available. Here, we investigated the potential of cerebrospinal fluid (CSF) lipocalin 2 (LCN2), a secreted glycoprotein that has been suggested as mediating neuronal damage in vascular brain injuries. The study included four independent cohorts with a total n = 472 samples. LCN2 was significantly elevated in VaD compared to controls, Alzheimer's disease (AD), other neurodegenerative dementias, and cognitively unimpaired patients with cerebrovascular disease. LCN2 discriminated VaD from AD without coexisting VaD with high accuracy. The main findings were consistent over all cohorts. Neuropathology disclosed a high percentage of macrophages linked to subacute infarcts, reactive astrocytes, and damaged blood vessels in multi-infarct dementia when compared to AD. We conclude that CSF LCN2 is a promising candidate biochemical marker in the differential diagnosis of VaD and neurodegenerative dementias.

Diagnostic Accuracy of Prion Disease Biomarkers in Iatrogenic Creutzfeldt-Jakob Disease.

Human prion diseases are classified into sporadic, genetic, and acquired forms. Within this last group, iatrogenic Creutzfeldt-Jakob disease (iCJD) is caused by human-to-human transmission through surgical and medical procedures. After reaching an incidence peak in the 1990s, it is believed that the iCJD historical period is probably coming to an end, thanks to lessons learnt from past infection sources that promoted new prion prevention and decontamination protocols. At this point, we sought to characterise the biomarker profile of iCJD and compare it to that of sporadic CJD (sCJD) for determining the value of available diagnostic tools in promptly recognising iCJD cases. To that end, we collected 23 iCJD samples from seven national CJD surveillance centres and analysed the electroencephalogram and neuroimaging data together with a panel of seven CSF biomarkers: 14-3-3, total tau, phosphorylated/total tau ratio, alpha-synuclein, neurofilament light, YKL-40, and real-time quaking induced conversion of prion protein. Using the cut-off values established for sCJD, we found the sensitivities of these biomarkers for iCJD to be similar to those described for sCJD. Given the limited relevant information on this issue to date, the present study validates the use of current sCJD biomarkers for the diagnosis of future iCJD cases.

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

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.

Cerebrospinal fluid non-phosphorylated tau in the differential diagnosis of Creutzfeldt-Jakob disease: a comparative prospective study with 14-3-3.

Cerebrospinal fluid (CSF) non-phosphorylated tau (non-p-tau) is increased in sporadic Creutzfeldt-Jakob disease (CJD), but its accuracy in the differential diagnosis has not been previously established. Here, we first used a retrospective cohort of non-CJD (n = 135) and CJD (n = 137) cases to determine the optimal cutoff point for the discrimination of CJD cases. Next, we prospectively quantified non-p-tau and 14-3-3 protein in a cohort of 1427 cases received for CSF testing at the German National Reference Center for transmissible spongiform encephalopathies. Among them, 36 were subsequently diagnosed as CJD. The diagnostic accuracy of both proteins discriminating CJD cases was evaluated. Using a cutoff of 650 pg/mL, non-p-tau displayed 94.39% accuracy in discriminating CJD cases, while 92.92% accuracy was achieved by 14-3-3 using a cutoff of 20,000 AU/mL. Diagnostic test evaluation for both proteins showed a slightly better performance of non-p-tau compared to 14-3-3. The two biomarkers' concentrations showed a significant positive correlation, both in the total population and in CJD cases (p < 0.001). Finally, the analysis of CSF non-p-tau concentrations when undergoing pre-analytical factors showed high stability in front of temperature storage and freeze/thaw cycles. Therefore, we conclude that when used in the appropriate clinical context of a prion disease surveillance center, non-p-tau is a highly sensitive and specific diagnostic marker for CJD.

Validation of Poly(Propylene Imine) Glycodendrimers Towards Their Anti-prion Conversion Efficiency.

Prion diseases, such as the sporadic Creutzfeldt-Jakob disease (sCJD), are a class of fatal neurodegenerative disorders. Currently, there is no efficient treatment or therapy available. Hence, the search for molecules that may inhibit the conversion of the cellular prion protein (PrPC) into its pathological counterpart PrPScrapie (PrPSc) is of great urgency. Here, we report the generation- and dose-dependent biological action of dense-shell poly(propylene imine) (PPI) glycodendrimers by using scrapie-infected neuroblastoma (ScN2a) cells and the real-time quaking-induced conversion assay (RT-QuIC) for validation of anti-prion efficiencies. Whereas the 2nd and 3rd generation of PPI glycodendrimers exhibited anti-prion conversion efficiency in ScN2a cells validated by RT-QuIC analysis, we observed that the 4th generation of glycodendrimers had shown no significant effect. Translational RT-QuIC studies conducted with human prions derived from sCJD patients indicated an anti-prion conversion effect (not on PrPRes degradation) of PPI glycodendrimers against human prions with the highest inhibitory activity of the 4th generation of PPI glycodendrimers towards prion aggregation compared to the 2nd and 3rd generation. In conclusion, our study highlights the potential of PPI glycodendrimers as therapeutic compounds due to their anti-conversion activity on human prions in a PrPSc strain depending manner.