Cerebrospinal fluid concentration of neuron-specific enolase in diagnosis of Creutzfeldt-Jakob disease

Creutzfeldt-Jakob Disease and Fatal Familial Insomnia: Demographics and In-Hospital Mortality in Spain

Background: Creutzfeldt-Jakob disease (CJD) and fatal familial insomnia (FFI) are prion diseases characterized by severe neurodegenerative conditions and a short duration of illness. Methods: This study explores the characteristics of hospitalizations for CJD and FFI in Spain from 2016 to 2022 using the Spanish National Hospital Discharge Database (SNHDD). Results: We identified a total of 1063 hospital discharges, including 1020 for CJD and 43 for FFI. Notably, the number of hospitalized patients with FFI showed a significant peak in 2017. The average length of hospital stay (LOHS) was 13 days for CJD and 6 days for FFI, with in-hospital mortality rates (IHM) of 36.37% for CJD and 32.56% for FFI. Among CJD patients, the average LOHS was 14 days, with a significantly longer duration for those who experienced IHM. Conclusions: The presence of sepsis or pneumonia and older age were associated with a higher IHM rate among CJD patients. The total estimated cost for managing CJD and FFI patients over the study period was EUR 6,346,868. This study offers new insights into the epidemiology and healthcare resource utilization of CJD and FFI patients, which may inform future research directions and public health strategies.

Neuron-specific enolase level is a useful biomarker for distinguishing amyotrophic lateral sclerosis from cervical spondylotic myelopathy

The current study aimed to evaluate whether cerebrospinal fluid (CSF) neuron-specific enolase (NSE) levels are elevated in amyotrophic lateral sclerosis (ALS) and are effective in distinguishing ALS from cervical spondylotic myelopathy (CSM). We retrospectively evaluated 45 patients with ALS, 23 with CSM, 28 controls, and 10 with Parkinson's disease (PD) who underwent analysis of CSF NSE levels. The control group comprised patients aged above 45 years who underwent lumbar puncture because of suspected neurological disorders that were ruled out after extensive investigations. CSF NSE levels were evaluated using the electro-chemiluminescent immunoassay. The ALS group had significantly higher CSF NSE levels than the CSM and control groups (P < 0.001 for both comparisons). The CSM, control, and PD groups did not significantly differ in terms of CSF NSE levels. A receiver-operating characteristic curve analysis was performed to assess the diagnostic value of CSF NSE levels in distinguishing ALS from CSM. The area under the curve for CSF NSE levels was 0.86. The optimal cutoff value was 17.7 ng/mL, with a specificity of 87% and a sensitivity of 80%. Hence, CSF NSE levels are elevated in ALS and are effective in distinguishing ALS from CSM.

Sporadic Creutzfeldt-Jakob disease: Real-Time Quaking Induced Conversion (RT-QuIC) assay represents a major diagnostic advance

Sporadic Creutzfeldt-Jakob disease (sCJD) is a rare and fatal neurodegenerative disorder with an incidence of 1.5 to 2 cases per million population/year. The disease is caused by a proteinaceous infectious agent, named prion (or PrPSc), which arises from the conformational conversion of the cellular prion protein (PrPC). Once formed, PrPSc interacts with the normally folded PrPC coercing it to undergo similar structural rearrangement. The disease is highly heterogeneous from a clinical and neuropathological point of view. The origin of this variability lies in the aberrant structures acquired by PrPSc. At least six different sCJD phenotypes have been described and each of them is thought to be caused by a peculiar PrPSc strain. Definitive sCJD diagnosis requires brain analysis with the aim of identifying intracerebral accumulation of PrPSc which currently represents the only reliable biomarker of the disease. Clinical diagnosis of sCJD is very challenging and is based on the combination of several clinical, instrumental and laboratory tests representing surrogate disease biomarkers. Thanks to the advent of the ultrasensitive Real-Time Quaking-Induced Conversion (RT-QuIC) assay, PrPSc was found in several peripheral tissues of sCJD patients, sometimes even before the clinical onset of the disease. This discovery represents an important step forward for the clinical diagnosis of sCJD. In this manuscript, we present an overview of the current applications and future perspectives of RT-QuIC in the field of sCJD diagnosis.

Clinical Use of Improved Diagnostic Testing for Detection of Prion Disease

Prion diseases are difficult to recognize as many symptoms are shared among other neurologic pathologies and the full spectra of symptoms usually do not appear until late in the disease course. Additionally, many commonly used laboratory markers are non-specific to prion disease. The recent introduction of second-generation real time quaking induced conversion (RT-QuIC) has revolutionized pre-mortem diagnosis of prion disease due to its extremely high sensitivity and specificity. However, RT-QuIC does not provide prognostic data and has decreased diagnostic accuracy in some rarer, atypical prion diseases. The objective of this review is to provide an overview of the current clinical utility of fluid-based biomarkers, neurodiagnostic testing, and brain imaging in the diagnosis of prion disease and to suggest guidelines for their clinical use, with a focus on rarer prion diseases with atypical features. Recent advancements in laboratory-based testing and imaging criteria have shown improved diagnostic accuracy and prognostic potential in prion disease, but because these diagnostic tests are not sensitive in some prion disease subtypes and diagnostic test sensitivities are unknown in the event that CWD transmits to humans, it is important to continue investigations into the clinical utility of various testing modalities.

Challenges and Advances in Antemortem Diagnosis of Human Transmissible Spongiform Encephalopathies

Transmissible spongiform encephalopathies (TSEs), also known as prion diseases, arise from the structural conversion of the monomeric, cellular prion protein (PrPC) into its multimeric scrapie form (PrPSc). These pathologies comprise a group of intractable, rapidly evolving neurodegenerative diseases. Currently, a definitive diagnosis of TSE relies on the detection of PrPSc and/or the identification of pathognomonic histological features in brain tissue samples, which are usually obtained postmortem or, in rare cases, by brain biopsy (antemortem). Over the past two decades, several paraclinical tests for antemortem diagnosis have been developed to preclude the need for brain samples. Some of these alternative methods have been validated and can provide a probable diagnosis when combined with clinical evaluation. Paraclinical tests include in vitro cell-free conversion techniques, such as the real-time quaking-induced conversion (RT-QuIC), as well as immunoassays, electroencephalography (EEG), and brain bioimaging methods, such as magnetic resonance imaging (MRI), whose importance has increased over the years. PrPSc is the main biomarker in TSEs, and the RT-QuIC assay stands out for its ability to detect PrPSc in cerebrospinal fluid (CSF), olfactory mucosa, and dermatome skin samples with high sensitivity and specificity. Other biochemical biomarkers are the proteins 14-3-3, tau, neuron-specific enolase (NSE), astroglial protein S100B, α-synuclein, and neurofilament light chain protein (NFL), but they are not specific for TSEs. This paper reviews the techniques employed for definite diagnosis, as well as the clinical and paraclinical methods for possible and probable diagnosis, both those in use currently and those no longer employed. We also discuss current criteria, challenges, and perspectives for TSE diagnosis. An early and accurate diagnosis may allow earlier implementation of strategies to delay or stop disease progression.

An Unbiased Immunization Strategy Results in the Identification of Enolase as a Potential Marker for Nanobody-Based Detection of Trypanosoma evansi

Trypanosoma evansi is a widely spread parasite that causes the debilitating disease “surra” in several types of ungulates. This severely challenges livestock rearing and heavily weighs on the socio-economic development in the affected areas, which include countries on five continents. Active case finding requires a sensitive and specific diagnostic test. In this paper, we describe the application of an unbiased immunization strategy to identify potential biomarkers for Nanobody (Nb)-based detection of T. evansi infections. Alpaca immunization with soluble lysates from different T. evansi strains followed by panning against T. evansi secretome resulted in the selection of a single Nb (Nb11). By combining Nb11-mediated immuno-capturing with mass spectrometry, the T. evansi target antigen was identified as the glycolytic enzyme enolase. Four additional anti-enolase binders were subsequently generated by immunizing another alpaca with the recombinant target enzyme. Together with Nb11, these binders were evaluated for their potential use in a heterologous sandwich detection format. Three Nb pairs were identified as candidates for the further development of an antigen-based assay for Nb-mediated diagnosis of T. evansi infection.

Evaluation of Human Cerebrospinal Fluid Malate Dehydrogenase 1 as a Marker in Genetic Prion Disease Patients

The exploration of accurate diagnostic markers for differential diagnosis of neurodegenerative diseases is an ongoing topic. A previous study on cerebrospinal fluid (CSF)-mitochondrial malate dehydrogenase 1 (MDH1) in sporadic Creutzfeldt–Jakob disease (sCJD) patients revealed a highly significant upregulation of MDH1. Here, we measured the CSF levels of MDH1 via enzyme-linked immunosorbent assay in a cohort of rare genetic prion disease cases, such as genetic CJD (gCJD) cases, exhibiting the E200K, V210I, P102L (Gerstmann–Sträussler–Scheinker syndrome (GSS)), or D178N (fatal familial insomnia (FFI)) mutations in the PRNP. Interestingly, we observed enhanced levels of CSF-MDH1 in all genetic prion disease patients compared to neurological controls (without neurodegeneration). While E200K and V210I carriers showed highest levels of MDH1 with diagnostic discrimination from controls of 0.87 and 0.85 area under the curve (AUC), FFI and GSS patients exhibited only moderately higher CSF-MDH1 levels than controls. An impact of the PRNP codon 129 methionine/valine (MV) genotype on the amount of MDH1 could be excluded. A correlation study of MDH1 levels with other neurodegenerative marker proteins revealed a significant positive correlation between CSF-MDH1 concentration with total tau (tau) but not with 14-3-3 in E200K, as well as in V210I patients. In conclusion, our study indicated the potential use of MDH1 as marker for gCJD patients which may complement the current panel of diagnostic biomarkers.

Clinical Laboratory Tests Used To Aid in Diagnosis of Human Prion Disease

Prion diseases are a group of rapidly progressive and always fatal neurodegenerative disorders caused by misfolded prion protein in the brain. Although autopsy remains the gold-standard diagnostic tool, antemortem laboratory testing can be performed to aid in the diagnosis of prion disease. This review is meant to help laboratory directors and physicians in their interpretation of test results. Laboratory assays to detect both nonspecific biomarkers of prion disease and prion-specific biomarkers can be used. The levels of nonspecific biomarkers in cerebrospinal fluid (CSF) are elevated when rapid neurodegeneration is occurring in the patient, and these markers include 14-3-3, tau, neuron-specific enolase, S100B, and alpha-synuclein. These markers have various sensitivities and specificities but are overall limited, as the levels of any of these analytes can be elevated in nonprion disease that is causing rapid damage of brain tissue. Prion-specific assays used in clinical laboratory testing are currently limited to two options. The first option is second-generation real-time quaking-induced conversion (RT-QuIC) performed on CSF, and the second option is Western blotting of a brain biopsy specimen used to detect protease-resistant prion protein. Although both tests have exquisite specificity, RT-QuIC has a sensitivity of 92 to 97.2% in symptomatic individuals, compared to the brain biopsy Western blot sensitivity of 20 to 60%. RT-QuIC was added to the Centers for Disease Control and Prevention's diagnostic criteria for prion disease in 2018. Other caveats of laboratory testing need to be considered, as sporadic, genetic, and acquired forms of prion disease have different clinical and laboratory presentations, and these caveats are discussed. Laboratory testing plays an important role in the diagnosis of prion disease, which is often challenging to diagnose.

14-3-3 and enolase abundances in the CSF of Prion diseased rats

Creutzfeldt-Jakob disease (CJD) is characterized by an extended asymptomatic preclinical phase followed by rapid neurodegeneration. There are no effective treatments. CJD diagnosis is initially suspected based upon the clinical presentation of the disease and the exclusion of other etiologies. Neurologic symptoms are assessed in combination with results from cerebrospinal fluid (CSF) biomarker abundances, electroencephalography (EEG), magnetic resonance imaging (MRI), and in some countries, real-time quaking-induced conversion (RT-QuIC). Inconsistencies in sensitivities and specificities of prion disease biomarker abundance in CSF have been described, which can affect diagnostic certainty, but the utility of biomarkers for prognosis has not been fully explored. The clinical presentation of CJD is variable, and factors such as prion protein polymorphic variants, prion strain, and other genetic or environmental contributions may affect the disease progression, confounding the appearance or abundance of biomarkers in the CSF. These same factors may also affect the appearance or abundance of biomarkers, further confounding diagnosis. In this study, we controlled for many of these variables through the analysis of serial samples of CSF from prion-infected and control rats. Prion disease in laboratory rodents follows a defined disease course as the infection route and time, prion strain, genotype, and environmental conditions are all controlled. We measured the relative abundance of 14-3-3 and neuron-specific enolase (NSE) in CSF during the course of prion infection in rats. Even when disease-related, environmental and genetic variables were controlled, CSF 14-3-3 and NSE abundances were variable. Our study emphasizes the considerable diagnostic and prognostic limitations of these prion biomarkers.

Serial NSE measurement identifies non-survivors following out of hospital cardiac arrest

AIMS

Prognostication following out-of-hospital cardiac arrest (OHCA) remains challenging. A multimodal approach is favoured, including consideration of the biomarker neuron-specific enolase (NSE) (Sandroni et al., 2014). Our objective was to investigate the utility of serial NSE measurements and to determine an appropriate cut-off value for prediction of death before hospital discharge using data from our tertiary care center.

METHODS

Retrospective analysis of patients admitted to the critical care unit of a tertiary center critical care unit in the UK following an out-of-hospital cardiac arrest.

MEASUREMENTS AND MAIN RESULTS

We analysed data from 72 patients admitted to our unit over 8 months following out-of-hospital cardiac arrest. Initial NSE level (NSE₀) was a poor predictor of outcome. Both NSE level at 48 h post-admission (NSE₄₈) and change in NSE from baseline to 48 h post-admission (Δ_NSE) were good predictors of outcome. A cut-off of NSE₄₈ > 69.8 ng/ml gave a specificity of 1.00 and sensitivity of 0.62 for prediction of death before hospital discharge in our patient group, whilst a cut-off of Δ_NSE > 31.3 ng/ml gave a specificity of 1.00 and sensitivity of 0.54. In patients who did not survive to hospital discharge, Δ_NSE > 9.4 ng/ml was associated with other poor prognostic factors (asytolic/PEA arrest, long downtime before ROSC) and with more rapid deterioration before death.

CONCLUSION

Serial measurement of NSE levels (at 0 and 48 h after admission) provides a useful tool to aid prognostication following out-of-hospital cardiac arrest.

Cerebrospinal Fluid Biomarkers of Alzheimer's Disease Show Different but Partially Overlapping Profile Compared to Vascular Dementia

Vascular factors increase the risks of developing Alzheimer's disease (AD) and they contribute to AD pathology. Since amyloid beta (Aβ) deposits can be observed in both diseases, there is an overlap which impedes a clear discrimination and difficult clinical diagnosis. In the present study, we compared cerebrospinal fluid (CSF) profiles of neurodegenerative and inflammatory biomarkers in a patient cohort of controls (n = 50), AD (n = 65) and vascular dementia (VaD) (n = 31) cases. Main results were validated in a second cohort composed of AD (n = 26), rapidly progressive AD (rpAD) (n = 15), VaD (n = 21), and cognitively unimpaired patients with vascular encephalopathy (VE) (n = 25) cases. In the study, cohort significant differences were detected in tau, p-tau, and Aβ1-42 (Aβ42) levels between AD and VaD patients, but not for the neuron-specific enolase (NSE), S100B protein, 14-3-3 and YKL-40. Differential tau, p-tau, and Aβ42 levels between AD and VaD were confirmed in the validation cohort, which additionally showed no differences between AD and rpAD, nor between VaD and VE. The evaluation of the biomarker performance in discrimination between AD and VaD patients revealed that the best diagnostic accuracy could be obtained when tau, p-tau, and Aβ42 were combined in form of Aβ42/p-tau (AUC 0.84-0.90, sensitivity 77-81%, specificity 80-93%) and (tau × p-tau)/Aβ42 ratio (AUC 0.83-0.87, sensitivity 73-81%, specificity 78-87%). Altogether, our studies provided neurodegenerative biomarker profiles in two cohorts of AD and VaD patients favoring the combination of CSF biomarker to differentiate between diseases.

Regulation of human cerebrospinal fluid malate dehydrogenase 1 in sporadic Creutzfeldt-Jakob disease patients

The identification of reliable diagnostic biomarkers in differential diagnosis of neurodegenerative diseases is an ongoing topic. A previous two-dimensional proteomic study on cerebrospinal fluid (CSF) revealed an elevated level of an enzyme, mitochondrial malate dehydrogenase 1 (MDH1), in sporadic Creutzfeldt-Jakob disease (sCJD) patients. Here, we could demonstrate the expression of MDH1 in neurons as well as in the neuropil. Its levels are lower in sCJD brains than in control brains. An examination of CSF-MDH1 in sCJD patients by ELISA revealed a significant elevation of CSF-MDH1 levels in sCJD patients (independently from the PRNP codon 129 MV genotype or the prion protein scrapie (PrPSc) type) in comparison to controls. In combination with total tau (tau), CSF-MDH1 detection exhibited a high diagnostic accuracy for sCJD diagnosis with a sensitivity of 97.5% and a specificity of 95.6%. A correlation study of MDH1 level in CSF with other neurodegenerative marker proteins revealed a significant positive correlation between MDH1 concentration with tau, 14-3-3 and neuron specific enolase level. In conclusion, our study indicated the potential of MDH1 in combination with tau as an additional biomarker in sCJD improving diagnostic accuracy of tau markedly.

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

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^Sc) 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^Sc 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.

Modulation of Creutzfeldt-Jakob disease prion propagation by the A224V mutation

OBJECTIVE

Mutations in the gene encoding the prion protein (PrP) are responsible for approximately 10 to 15% of cases of prion disease in humans, including Creutzfeldt-Jakob disease (CJD). Here, we report on the discovery of a previously unreported C-terminal PrP mutation (A224V) in a CJD patient exhibiting a disease similar to the rare VV1 subtype of sporadic (s) CJD and investigate the role of this mutation in prion replication and transmission.

METHODS

We generated transgenic (Tg) mice expressing human PrP with the V129 polymorphism and A224V mutation, denoted Tg(HuPrP,V129,A224V) mice, and inoculated them with different subtypes of sCJD prions.

RESULTS

Transmission of sCJD VV2 or MV2 prions was accelerated in Tg(HuPrP,V129,A224V) mice, compared to Tg(HuPrP,V129) mice, with incubation periods of ∼110 and ∼210 days, respectively. In contrast, sCJD MM1 prions resulted in longer incubation periods in Tg(HuPrP,V129,A224V) mice, compared to Tg(HuPrP,V129) mice (∼320 vs. ∼210 days). Prion strain fidelity was maintained in Tg(HuPrP,V129,A224V) mice inoculated with sCJD VV2 or MM1 prions, despite the altered replication kinetics.

INTERPRETATION

Our results suggest that A224V is a risk factor for prion disease and modulates the transmission behavior of CJD prions in a strain-specific manner, arguing that residues near the C-terminus of PrP are important for controlling the kinetics of prion replication.

Molecular diagnostic tools in Creutzfeldt-Jakob disease and other prion disorders

Clinical criteria and cerebrospinal fluid biomarkers for the diagnosis of human prion diseases (sporadic, iatrogenic or variant Creutzfeldt-Jakob disease and genetic inherited transmissible spongiform encephalopathies) are now widely available and show a sensitivity and specificity of approximately 98%. Final diagnosis of prion diseases is obtained by post-mortem examination upon identification of the pathological conformer of the prion protein (PrPSc) in the brain. Several diagnostic kits are now available that facilitate the immunochemical measurement of PrPSc. Several new molecular diagnostic techniques, aimed at increasing the sensitivity and specificity of PrPSc detection and at identifying markers of disease other than PrPSc, are the subject of ongoing studies. The aim of these studies is to develop preclinical screening tests for the identification of infected but still healthy individuals. These tests are also essential to investigate the safety of blood or blood-derived products and to ensure meat safety in European countries.

APOE gene polymorphisms and susceptibility to Creutzfeldt-Jakob disease

Associations between apolipoprotein E (APOE) gene polymorphisms and Creutzfeldt-Jakob disease (CJD) have been reported, but the results from many of these studies are conflicting. To investigate the association between APOE polymorphisms and CJD risk, we performed a meta-analysis. We used odds ratios (OR) with 95% confidence intervals (CI) to assess the strength of the association. The frequency of putative risk alleles in control subjects was estimated with the Mantel-Haenszel method. Cochran's Q statistic and the inconsistency index (I(2)) were used to test heterogeneity. Egger's test and an inverted funnel plot were used to assess bias. Our study included 11 published case-control studies with APOE genotyping, involving a total of 1001 CJD patients and 1211 controls. Overall, the APOE 34 (OR 1.37, 95% CI: 1.09-1.72), and APOE 44 (OR 3.16, 95% CI: 1.37-7.26) genotypes and the APOE 4 (OR 1.41, 95% CI: 1.08-1.85) allele were associated with an increased risk of CJD, and the APOE 33 (OR 0.81, 95% CI: 0.67-0.97) genotype tended to protect against CJD. However, we did not find significant evidence supporting associations of the APOE 22 (OR 1.15, 95% CI: 0.45-2.93), APOE 23 (OR 0.84, 95% CI: 0.64-1.09), or APOE 24 (OR 1.40, 95% CI: 0.70-2.77) genotypes, nor the APOE 2 (OR 1.02, 95% CI: 0.73-1.42) or APOE 3 (OR 0.82, 95% CI: 0.65-1.02) alleles with CJD using a fixed-effects model. Our results support a genetic association between APOE polymorphisms and CJD.

Serum and cerebrospinal fluid neuron-specific enolase for diagnosis of tuberculous meningitis

PURPOSE

Late diagnosis and treatment lead to high mortality and poor prognosis in tuberculous meningitis (TbM). A rapid and accurate diagnosis is necessary for a good prognosis. Neuron-specific enolase (NSE) has been investigated as a biochemical marker of nervous tissue damage. In the present study, the usefulness of NSE was evaluated, and a cut-off value for the differential diagnosis of TbM was proposed.

MATERIALS AND METHODS

Patient charts were reviewed for levels of serum and cerebrospinal fluid (CSF) NSE, obtained from a diagnostic CSF study of samples in age- and gender-matched TbM (n=15), aseptic meningitis (n=28) and control (n=37) patients.

RESULTS

CSF/serum NSE ratio was higher in the TbM group than those of the control and aseptic groups (p=0.001). In binary logistic regression, CSF white blood cell count and CSF/serum NSE ratio were significant factors for diagnosis of TbM. When the cut-off value of the CSF/serum NSE ratio was 1.21, the sensitivity was 86.7% and the specificity was 75.4%.

CONCLUSION

The CSF/serum NSE ratio could be a useful parameter for the early diagnosis of TbM. In addition, the authors of the present study suggest a cut-off value of 1.21 for CSF/serum NSE ratio.

A comprehensive study of repetitive transcranial magnetic stimulation in Parkinson's disease

The clinical benefits of repetitive transcranial magnetic stimulation (rTMS) for Parkinson's disease (PD) remain controversial. We performed a comprehensive study to examine whether rTMS is a safe and effective treatment for PD. Twelve PD patients received rTMS once a week. The crossover study design consisted of 4-week sham rTMS followed by 4-week real rTMS. The Unified Parkinson's Disease Rating Scale (UPDRS), Modified Hoehn and Yahr Stage, Schwab and England ADL Scale, Actigraph, Mini-Mental State Examination, Hamilton Depression Scale, Wechsler Adult Intelligence Scale-revised, and cerebral blood flow (CBF) and cerebrospinal fluid (CSF) examinations were used to evaluate the rTMS effects. Under both drug-on and drug-off conditions, the real rTMS improved the UPDRS scores significantly, while the sham rTMS did not. There were no significant changes in the results of the neuropsychological tests, CBF and CSF. rTMS seems to be a safe and effective therapeutic option for PD patients, especially in a wearing-off state.

Ovine serum biomarkers of early and late phase scrapie

Background

Transmissible spongiform encephalopathies are fatal neurodegenerative disease occurring in animals and humans for which no ante-mortem diagnostic test in biological fluids is available. In such pathologies, detection of the pathological form of the prion protein (i.e., the causative factor) in blood is difficult and therefore identification of new biomarkers implicated in the pathway of prion infection is relevant.

Methods

In this study we used the SELDI-TOF MS technology to analyze a large number of serum samples from control sheep and animals with early phase or late phase scrapie. A few potential low molecular weight biomarkers were selected by statistical methods and, after a training analysis, a protein signature pattern, which discriminates between early phase scrapie samples and control sera was identified.

Results

The combination of early phase biomarkers showed a sensitivity of 87% and specificity of 90% for all studied sheep in the early stage of the disease. One of these potential biomarkers was identified and validated in a SELDI-TOF MS kinetic study of sera from Syrian hamsters infected by scrapie, by western blot analysis and ELISA quantitation.

Conclusions

Differential protein expression profiling allows establishing a TSE diagnostic in scrapie sheep, in the early phase of the disease. Some proteic differences observed in scrapie sheep exist in infected hamsters. Further studies are being performed to identify all the discriminant biomarkers of interest and to test our potential markers in a new cohort of animals.

Cerebrospinal fluid biomarkers in human prion diseases

Cerebrospinal fluid (CSF) is the main component of the brain extracellular space and participates in the exchange of many biochemical products in the CNS. Consequently, CSF contains a dynamic and complex mixture of proteins that reflect the physiological or pathological state of the CNS. Changes in the CSF proteome have been described in various neurodegenerative disorders. These alterations are also thought to reflect pathological changes in the brain, and thus understanding them will contribute to a better awareness of the pathophysiology that underlies these disorders. Proteomics offers a new methodology for the analysis of pathological changes and mechanisms occurring in neurodegenerative processes and provides the possibility of novel biomarker discovery in order to supplement faster, earlier and more precise diagnosis. In general, the following criteria have to be applied in order to qualify a protein or a gene as a potential biomarker: the selected parameters have to be sensitive (able to detect the abnormalities at early stage of disease), specific (to allow differential diagnosis), reproducible with a high positive predictive value, and should allow for disease monitoring as well as a potential therapeutic response. In Creutzfeldt–Jakob disease, two major approaches have been followed that aim to detect the pathological form of the prion protein (PrPSc) in various peripheral tissues, while other approaches look for surrogate parameters that are a consequence of the neurodegenerative process. While the amount of abnormal disease-related PrPSc in CSF and blood in human transmissible spongiform encephalopathies appears to be extremely low, the development of a PrPSc-based biomarker was hampered by technical problems and detection limits. However, a variety of other proteins have been investigated in the CSF, and recently a variety of potential biomarkers have been reported that contribute to clinical diagnosis. Already established markers are 14-3-3, β-amyloid, tau-protein and phosphorylated isoforms, S100b, as well as neuron-specific enolase. Since some of these markers display certain limitations, the search continues. This review summarizes current knowledge of biomarker development in prion diseases and discusses perspectives for new approaches.

Cerebrospinal fluid biomarkers of neurodegeneration in chronic neurological diseases

Chronic neurological diseases (CND) like amyotrophic lateral sclerosis (ALS), dementia or multiple sclerosis (MS) share a chronic progressive course of disease that frequently leads to the common pathological pathway of neurodegeneration, including neuroaxonal damage, apoptosis and gliosis. There is an ongoing search for biomarkers that could support early diagnosis of CND and help to identify responders to interventions in therapeutic treatment trials. Cerebrospinal fluid (CSF) is a promising source of biomarkers in CND, since the CSF compartment is in close anatomical contact with the brain interstitial fluid, where biochemical changes related to CND are reflected. We review recent advances in CSF biomarkers research in CND and thereby focus on markers associated with neurodegeneration.

Evidence for a pathogenic role of different mutations at codon 188 of PRNP

Clinical and pathological changes in familial Creutzfeldt-Jakob disease (CJD) cases may be similar or indistinguishable from sporadic CJD. Therefore determination of novel mutations in PRNP remains of major importance.

We identified two different rare mutations in codon 188 of the prion protein gene (PRNP) in four patients suffering from a disease clinically very similar to the major subtype of sporadic CJD. Both mutations result in an exchange of the amino acid residue threonine for a highly basic residue, either arginine (T188R) or lysine (T188K). The T188R mutation was found in one patient and the T188K mutation in three patients. The prevalence of mutations at codon 188 of PRNP was tested in 593 sporadic CJD cases and 735 healthy individuals. Neither mutation was found. The data presented here argue in favor of T188K being a pathogenic mutation causing genetic CJD. Since one individual with this mutation, who is the father of a clinically affected patient with T188K mutation, is now 79 years old and shows no signs of disease, this mutation is likely associated with a penetrance under 100%. Further observations will have to show whether T188R is a pathogenic mutation.

Cerebrospinal Fluid and Serum Neuron-Specific Enolase in Acute Benign Headache

We determined the cerebrospinal fluid (CSF) and serum neuron-specific enolase (NSE) concentrations in 19 patients with acute benign headache. All patients had normal neurological examination, CSF and head computed tomography scan. The final diagnoses were: primary thunderclap headache ( n = 7), primary exertional headache ( n = 3), primary cough headache ( n = 1), migraine without aura ( n = 4), headache unspecified ( n = 2), probable infrequent episodic tension-type headache ( n = 1), headache attributed to hypertensive crisis without hypertensive encephalopathy ( n = 1). A group of 108 healthy subjects served as controls. CSF NSE concentration was 14.16 ng/ml [95% confidence interval (CI) 11.86, 16.47)] in the headache sample (controls 17.19 ng/ml, 95% CI 16.23, 18.15). Serum NSE concentration was 7.50 ng/ml (95% CI 5.20, 9.80) in the headache sample (controls 8.45 ng/ml, 95% CI 7.67, 9.23). CSF/serum ratio was 2.81 (95% CI 2.21, 3.40) in the headache sample (controls 2.23, 95% CI 2.03, 2.42). Acute benign headache is not associated with neuronal damage as estimated by means of CSF and serum NSE concentration.

Current state and future directions of neurochemical biomarkers for Alzheimer's disease

In this comprehensive review, we summarize the current state-of-the-art of neurochemical biomarkers for Alzheimer's disease. Predominantly, these biomarkers comprise cerebrospinal fluid biomarkers directly related to the pathophysiology of this disorder (such as amyloid beta protein, tau protein). We particularly pay attention to the innovations in this area that have been made in technological aspects during the past 5 years (e.g., multiplex analysis of biomarkers, proteomics), to the discovery of novel, potential biomarkers (e.g., amyloid beta oligomers, isoprostanes), and to the extension of this research towards identification of biomarkers in plasma.

14-3-3 CSF levels in sporadic Creutzfeldt-Jakob disease differ across molecular subtypes

BACKGROUND

The 14-3-3 protein is a physiological cellular protein expressed in various tissues, and its release to CSF reflects extensive neuronal damage as in Creutzfeldt-Jakob disease (CJD), but also in other neurological diseases. 14-3-3 protein in CSF in the proper clinical context is a reliable diagnostic tool for sporadic CJD. However, the sensitivity varies across molecular CJD subtypes.

OBJECTIVE

We determined the level of the 14-3-3 protein in CSF from 70 sporadic CJD patients with distinct molecular subtypes using an improved enzyme-linked immunosorbent assay (ELISA) protocol technique.

RESULTS

The 14-3-3 levels varied markedly across various molecular subtypes. The most elevated levels of 14-3-3 protein were observed in the frequently occurring and classical subtypes, whereas the levels were significantly lower in the subtypes with long disease duration and atypical clinical presentation. PRNP codon 129 genotype, PrP(sc) isotype, disease stage and clinical subtype influenced the 14-3-3 level and the test sensitivity.

CONCLUSIONS

The 14-3-3 protein levels differ across molecular subtypes and might be used for their early pre-mortem identification when the codon 129 genotype is known, especially for the less common molecular subtypes such as MV2 and MM2.

Neuron Specific Enolase (NSE): A Valuable Prognostic Factor of Central Nervous System Dysfunction Following Cardiac Surgery

Purpose

The aim of this study was to evaluate neuron specific enolase (NSE) as prognostic factor for CNS disorders developed in relation to cardiac surgery.

Patients and methods

A cohort of 92 patients were divided into two groups; the experimental group consisted of patients undergoing open-heart bypass surgery (50 patients) and the control group consisting of 42 patients undergoing general surgery procedures. The blood levels of NSE were measured in both groups before and 24 h after the operation and have been related to the incidence of the postoperative brain damage as well as to the duration of the extracorporeal circulation (ECC).

Results

The analysis of our results showed that the changes of blood NSE levels, before and immediately after ECC in open-heart surgery have been related to the incidence of postoperative brain dysfunction according to a specific mathematical equation. This incidence was raised also in relation to the age of the patient and the duration of ECC. On the contrary, NSE seems to have no prognostic value in general surgery.

Conclusion

NSE can be used in cardiac surgery as a simple and reliable prognostic factor to predict postoperative brain dysfunction.

Influence of timing on CSF tests value for Creutzfeldt-Jakob disease diagnosis

Background

The analysis of markers in the cerebrospinal fluid (CSF) is useful in the diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD). However, the time at which the study of these markers is most sensitive remains controversal.

Objective

To assess the influence of time of sampling on the value of CSF tests in the diagnosis of sCJD.

Method

In the framework of a multinational European study, we studied the results of 14-3-3, S100b, neurone specific enolase (NSE) and tau protein in 833 CSF samples from sCJD patients at different stages of disease and in 66 sequentially repeated lumbar punctures (LP).

Results

14-3-3 and tau protein tended to increase in sensitivity from onset (88%, 81%) to the advanced stage (91%, 90%). This was significant only in the methionine-valine (MV) heterozygous group of patients at codon 129. The absolute levels of S100b (p < 0.05), NSE and tau protein increased in the last stage of disease. High levels of tau protein, NSE and S100b were associated with shorter survival times (p < 0.01). Sixty-six sCJD patients underwent repeated LP. These sCJD patients were younger, had longer disease durations and were more frequently MV at codon 129 (p < 0.001) than the whole group. 14-3-3 sensitivity increased from 64% to 82% in the second LP (p = 0.025) and 88% sCJD patients had at least one positive result.

Conclusions

Sensitivity and absolute levels of CJD markers increased with disease progression and were modulated by the codon 129 genotype. Early negative results should be inter-preted with caution, especially in young patients or those who are MV at codon 129.

Update on human prion disease

The recognition that variant Creutzfeldt-Jakob disease (vCJD) is caused by the same prion strain as bovine spongiform encephalopathy in cattle has dramatically highlighted the need for a precise understanding of the molecular biology of human prion diseases. Detailed clinical, pathological and molecular data from a large number of human prion disease patients indicate that phenotypic diversity in human prion disease relates in part to the propagation of disease-related PrP isoforms with distinct physicochemical properties. Incubation periods of prion infection in humans can exceed 50 years and therefore it will be some years before the extent of any human vCJD epidemic can be predicted with confidence.

An overview of transmissible spongiform encephalopathies

Transmissible spongiform encephalopathies (TSEs) are fatal neurodegenerative disorders of humans and animals associated with an accumulation of abnormal isoforms of prion protein (PrP) in nerve cells. The pathogenesis of TSEs involves conformational conversions of normal cellular PrP (PrPc) to abnormal isoforms of PrP (PrPSc). While the protein-only hypothesis has been widely accepted as a causal mechanism of prion diseases, evidence from more recent research suggests a possible involvement of other cellular component(s) or as yet undefined infectious agent(s) in PrP pathogenesis. Although the underlying mechanisms of PrP strain variation and the determinants of interspecies transmissibility have not been fully elucidated, biochemical and molecular findings indicate that bovine spongiform encephalopathy in cattle and new-variant Creutzfeldt–Jakob disease in humans are caused by indistinguishable etiological agent(s). Cumulative evidence suggests that there may be risks of humans acquiring TSEs via a variety of exposures to infected material. The development of highly precise ligands is warranted to detect and differentiate strains, allelic variants and infectious isoforms of these PrPs. This article describes the general features of TSEs and PrP, the current understanding of their pathogenesis, recent advances in prion disease diagnostics, and PrP inactivation.

14-3-3 protein levels and isoform patterns in the cerebrospinal fluid of Creutzfeldt-Jakob disease patients in the progressive and terminal stages

To elucidate the diagnostic value and to establish the 14-3-3 isoform patterns in the cerebrospinal fluid (CSF) of Creutzfeldt-Jakob disease (CJD) patients, we analysed the 14-3-3 isoform patterns in the CSF of 11 CJD patients using the Western immunoassay technique. 14-3-3 protein was detected in the CSF of seven CJD patients in the progressive stage, but not in four patients in the terminal stages whose brains were severely atrophied. The amount of 14-3-3 protein measured semi-quantitatively in the CSF was correlated with that of neuron-specific enolase measured using an enzyme-linked immunosorbent assay in the same CSF. CJD patients showed five dominant 14-3-3 isoforms, gamma, epsilon, zeta, eta and beta, but 14-3-3 tau, which mainly originates from T lymphocytes, was not detected. 14-3-3 protein is released into the CSF as a consequence of the extensive and rapid destruction of the brain, and the presence of the five isoforms enhances the diagnostic value of 14-3-3 protein in the progressive stage.

Comparative proteomics of cerebrospinal fluid in neuropathologically-confirmed Alzheimer's disease and non-demented elderly subjects

OBJECTIVES

Diagnostic tests able to reveal Alzheimer's disease (AD) in living patients before cognitive ability is destroyed are urgently needed. Such tests must distinguish AD from other dementia causes, as well as differentiate subtle changes associated with normal aging from true pathology emergence. A single biomarker offering such diagnostic and prognostic capacities has eluded identification. Therefore, a valuable test for AD is likely to be based on a specific pattern of change in a set of proteins, rather than a single protein.

METHODS

We examined pooled cerebrospinal fluid (CSF) samples obtained from neuropathologically-confirmed AD (n=43) and non-demented control subjects (n=43) using 2-dimensional gel electrophoresis (2DE) proteomic methodology to detect differentially expressed proteins. Proteins exhibiting expression level differences between the pools were recovered and identified using matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry.

RESULTS

Five differentially-expressed proteins with potential roles in amyloid-beta metabolism and vascular and brain physiology [apolipoprotein A-1 (Apo A-1), cathepsin D (CatD), hemopexin (HPX), transthyretin (TTR), and two pigment epithelium-derived factor (PEDF) isoforms] were identified. Apo A-1, CatD and TTR were significantly reduced in the AD pool sample, while HPX and the PEDF isoforms were increased in AD CSF.

DISCUSSION

These results suggest that multi-factor proteomic pattern analysis of the CSF may provide a means to diagnose and assess AD.

Cerebrospinal fluid biomarkers in Creutzfeldt–Jakob disease

Creutzfeldt-Jakob disease (CJD) is a rare neurodegenerative disorder. Since the emergence of variant CJD (vCJD) vigilance concerning the disease's incidence has increased and the interest in accurate in vivo diagnosis has augmented. So far, a large number of biomarkers has been investigated as aid in the differential diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD) and vCJD. These include, among others, neuron-specific enolase (NSE), microtubuli associated protein Tau, S-100beta, amyloid-beta (Abeta(1-42)) and the 14-3-3 protein. Multiple studies have confirmed that CSF detection of 14-3-3 protein by Western blot was the best single biomarker for sCJD with an average sensitivity and specificity of 92%. Also, in genetic and iatrogenic CJD (iCJD) patients with an average disease duration of less than 1 year, 14-3-3 is the best differential biomarker. Unfortunately, the 14-3-3 protein has a lower sensitivity if the disease duration exceeds beyond 1 year in both sporadic CJD and other CJD types (vCJD, and specific genetic or iatrogenic CJD types).

Cerebrospinal fluid and serum neuron-specific enolase concentrations in a normal population*

The aim of this study was to determine cerebrospinal fluid (CSF) and serum neuron-specific enolase (NSE) concentrations in a normal population and to analyse their relationship with sex and age. The sample was recruited among patients undergoing spinal anaesthesia, without neurological diseases. NSE was determined by means of immunometric assay. One hundred and eight patients (68 men) were recruited. CSF-NSE concentration was (mean +/- SD) 17.3 +/- 4.6 ng/ml (men 17.4 +/- 4.2, women 17.0 +/- 5.2, P = 0.62); serum concentration was 8.7 +/- 3.9 ng/ml (men 8.9 +/- 3.9, women 8.3 +/- 4.0, P = 0.06). The mean CSF/serum NSE ratio was 2.3 +/- 0.8 (men 2.2 +/- 0.8, women 2.4 +/- 0.9, P = 0.22). In both sexes, simple regression analysis showed not significantly increasing concentrations with advancing age for both CSF and serum NSE. Serum and CSF concentrations did not correlate in both sexes. In our study, CSF-NSE was twice the serum concentration; both were not influenced by sex or age. Serum and CSF-NSE values vary widely among different studies on normal populations because of different determination methods; therefore, each laboratory should obtain its own reference values. Finally, serum NSE should be used with caution as an indicator of CSF concentration as no correlation could be demonstrated between them in our study.

Immunoglobulins and virus-specific antibodies in patients with Creutzfeldt-Jakob disease

OBJECTIVES

Cerebrospinal fluid (CSF) pattern in patients with neuropathologically diagnosed Creutzfeldt-Jakob disease was analyzed.

MATERIAL AND METHODS

Routine tests included white blood cells count, protein, albumin, immunoglobulins and the presence of oligoclonal immunoglobulin G (IgG) in the CSF as well as the calculation of intrathecal synthesis of immunoglobulins by standard methods. In addition, antibodies against neurotropic viruses such as measles, rubella, varicella zoster and herpes simplex were measured and the specific antibody index was calculated.

RESULTS

A blood-CSF barrier dysfunction was observed in six of 25 cases. In CSF/serum quotient diagrams, no patient had intrathecally synthesized immunoglobulins, but in two of 25 patients oligoclonal bands were detected. Two patients had intrathecally synthesized antibodies against varicella zoster and three against herpes simplex virus.

CONCLUSION

In conclusion, in the routine diagnosis, the CSF in CJD is normal in most cases. In some patients, abnormalities include the blood-CSF barrier dysfunction, mild pleocytosis, oligoclonal bands and intrathecally synthesized viral antibodies.

Use of neuron-specific enolase for assessing the severity and outcome of neurological disorders in patients

Neuron-specific enolase (NSE) is a glycolytic enzyme present almost exclusively in neurons and neuroendocrine cells. NSE levels in cerebrospinal fluid (CSF) are assumed to be useful to estimate neuronal injury and clinical outcome of patients with serious clinical manifestations such as those observed in stroke, head injury, anoxic encephalopathy, encephalitis, brain metastasis, and status epilepticus. We compared levels of NSE in serum (sNSE) and in CSF (cNSE) among four groups: patients with meningitis (N=11), patients with encephalic injuries associated with impairment of consciousness (ENC, N=7), patients with neurocysticercosis (N=25), and normal subjects (N=8). Albumin was determined in serum and CSF samples, and the albumin quotient was used to estimate blood-brain barrier permeability. The Glasgow Coma Scale score was calculated at the time of lumbar puncture and the Glasgow Outcome Scale (GOS) score was calculated at the time of patient discharge or death. The ENC group had significantly higher cNSE (P=0.01) and albumin quotient (P=0.005), but not sNSE (P=0.14), levels than the other groups (Kruskal-Wallis test). Patients with lower GOS scores had higher cNSE levels (P=0.035) than patients with favorable outcomes. Our findings indicate that sNSE is not sensitive enough to detect neuronal damage, but cNSE seems to be reliable for assessing patients with considerable neurological insult and cases with adverse outcome. However, one should be cautious about estimating the severity of neurological status as well as outcome based exclusively on cNSE in a single patient.

Neuron-specific enolase in patients with neurocysticercosis

BACKGROUND

Neurocysticercosis (NC) is the most frequent parasitic disease of the human nervous system. Its clinical manifestations are varied and depend on the number and location of cysts, as well as the host immune response. Symptoms in NC usually occur when cysts enter into a degenerative phase associated with perilesional inflammation. We speculate that neuron-specific enolase (NSE)--a marker of neuronal injury--could be elevated in patients with degenerating cysts comparing to those with viable cysts.

METHODS

We examined serum NSE (sNSE) and cerebrospinal fluid (CSF) NSE (cNSE) levels in 25 patients with NC: 14 patients with degenerative cysts (D), 8 patients with viable cysts (V) and 3 patients with inactive cysts. Samples of eight normal controls (C) were also obtained. Determination of albumin was performed in serum and CSF samples, and the CSF/serum albumin ratio (albumin quotient, Q(alb)) was used to estimate the blood-brain barrier permeability.

RESULTS

All patients, with the exception of one case, had five or less cysts. Comparisons between V, D and C groups did not demonstrate significant differences of cNSE, Q(alb) and sNSE levels. Further, there were no significant differences of cNSE and sNSE levels between patients with or without intracranial hypertension (ICH).

CONCLUSIONS

These findings suggest that the inflammatory response associated with a relatively small number of degenerating cysts does not provoke significant neuronal damage. Further studies considering patients with a larger number of cysts will be required to assess if there is evidence of neuronal damage in such more severe cases.

Lateralized and focal clinical, EEG, and FLAIR MRI abnormalities in Creutzfeldt-Jakob disease

OBJECTIVE

Creutzfeldt-Jakob disease (CJD) is a rapidly progressive fatal prion disorder with typical clinical findings of dementia, motor dysfunction, and myoclonus and characteristic electroencephalographic (EEG) findings of bilateral synchronous periodic sharp waves. Advances in neuroimaging capabilities with diffusion-weighted and fluid-attenuated inversion recovery (FLAIR) magnetic resonance imaging (MRI) techniques have shown promise in the non-invasive diagnosis of CJD. This series illustrates the correlation between the lateralized and focal clinical, EEG, and MRI FLAIR sequence abnormalities in 8 patients (7 men and one woman 55-73 years old) with CJD.

METHODS

A case series of 8 patients, evaluated at Mayo Clinic, who had a history of rapidly progressive lateralized or focal neurologic dysfunction and laboratory findings consistent with CJD between 1996 and 1999 were identified. EEG, MRI of the head with FLAIR sequence, and cerebrospinal fluid studies were performed in all patients.

RESULTS

Mean time to death from symptom onset was 4 months. Symptoms were lateralized to the left hemisphere in 5 patients and to the right hemisphere in two. One patient showed bilateral occipital lobe involvement. In all patients, the EEG showed lateralized or focal periodic sharp waves that colocalized with clinical cerebral dysfunction. FLAIR MRI images revealed increased signal in the cortical ribbon and deep gray matter corresponding to the lateralized clinical and EEG findings in 7 patients. The other patient had bilateral occipital increased signal on FLAIR MRI.

CONCLUSIONS

CJD may present with lateralized or focal cortical syndromes with colocalizing EEG and MRI findings. With the appropriate clinical history and laboratory evaluation, the corresponding areas of increased signal on FLAIR MRI provide supportive evidence of the disease.

SIGNIFICANCE

CJD can sometimes present with more focal or lateralized clinical findings, and the colocalizing EEG and MRI findings can help make or confirm the diagnosis of CJD.

A prospective study of CSF markers in 250 patients with possible Creutzfeldt-Jakob disease

OBJECTIVE

To investigate various cerebrospinal fluid (CSF) markers that could assist in the clinical diagnosis of Creutzfeldt-Jakob disease (CJD).

METHODS

CSF samples were analysed for the presence of 14-3-3 protein, microtubule associated protein tau, and beta amyloid in 250 patients with possible CJD. Densitometric analysis was used to quantify the level of 14-3-3 in all patients.

RESULTS

Analysis of the clinical data showed that cerebellar signs or myoclonus combined with progressive dementia were the main features leading to a clinical suspicion of CJD. While 14-3-3 detection had a sensitivity of 100% and a specificity of 92%, tau determination using a threshold of 1300 pg/ml had a sensitivity of 87% and a specificity of 97%. If the protocol for the analysis of 14-3-3 was modified (using densitometric analysis) a higher specificity (97%) could be obtained, but with a lower sensitivity (96%). Maximum sensitivity, specificity, and positive predictive value were obtained with a combination of 14-3-3 and beta amyloid determinations. The concentrations of 14-3-3 and tau in the CSF were reduced in CJD patients with a long duration of disease (more than one year; p < 0.05). The concentrations of 14-3-3 or tau were lowest at the onset or at the end stage of the disease, while the beta amyloid concentration remained low throughout the course of the disease.

CONCLUSIONS

Both 14-3-3 and tau protein are sensitive and specific biomarkers for CJD. The combination of 14-3-3 and beta amyloid analysis resulted in the maximum sensitivity, specificity, and positive predictive value. When these biomarkers are used in the diagnosis of CJD, the phase of the disease in which the CSF sample was obtained should be taken into account. Disease duration, dependent on the PrP genotype, also has a significant influence on the level of 14-3-3 and tau in the CSF.

[Level of S-100 and neuron-specific enolase in cerebrospinal fluid from subjects with neurological pathologies]

AIM

To evaluate S-100 and neuro specific enolase (NSE) levels in cerebrospinal fluid (CSF) from patients with differents neurological disorders in order to study possible differences in their protein concentrations.

MATERIAL AND METHODS

We analysed samples of CSF taked by spinal puncture in subjects either from of the Casualty Department or from the Department of Neurology. Patients displaying neurological symptoms capable of being diagnostically tested. The total number of patients-samples examined was 43 (23 males and 20 females; mean age 43 y, range 1-78 y). Five patients groups were studied: a control group, meningitis, dementia, polyneuropathy-motorneuron disease, and acute cerebral infarction group (ACV). S-100 and NSE concentrations were measured by immunoradiometric procedures.

RESULTS

Highest S-100 median levels in CSF were found in dementia and ACV group, with elevate concentrations in meningitis groups. The increased S-100 levels in these groups was significant compared with control group (Mann-Withney U test). For NSE concentrations, there is a significant differences between dementia group and control group. No other significant differences were found between groups. There were positive correlation between S-100 levels and total protein.

CONCLUSION

Our results suggest that S-100 and NSE can be a sensitive marker of brain damage in different neurological disorders. However, levels must be considered individually, since these concentrations depend on several factors, such as age, severity of brain damage or interval between the onset of brain damage and the taking of the sample.

Molecular classification of sporadic Creutzfeldt-Jakob disease

According to the protein-only hypothesis of prion propagation, an abnormal isoform (designated PrP(Sc)) of the cellular prion protein (PrP(C)) is the principal or sole component of transmissible prions. However, the existence of multiple prion strains has been difficult to accommodate within this hypothesis. We have previously reported the identification of four types of human PrP(Sc) associated with sporadic and acquired human prion diseases. These PrP(Sc) types are distinguished by differing molecular mass of fragments following limited proteinase K digestion and by differing ratios of di-, mono- and unglycosylated PrP(Sc). That these discrete biochemical features of PrP(Sc) are serially transmissible to human PrP in transgenic mice following experimental transmission suggests that they may be responsible for encoding prion strain diversity. Here we present detailed clinical, pathological and molecular data from a large number of sporadic Creutzfeldt-Jakob disease (CJD) cases. We show that PrP(Sc) types are associated with codon 129 status, duration of illness and neuropathological phenotype. A novel PrP(Sc) type is presented, illustrating further heterogeneity in CJD, and suggesting that further molecular subtypes of CJD may exist at lower frequencies. A molecular classification of sporadic CJD is proposed.

Diagnosis of prion diseases

This article reviews the various techniques and methodologies for the recognition and diagnosis of clinical and neuropathologic variants of human prion diseases.