Markus Otto

Elevated levels of tau-protein in cerebrospinal fluid of patients with Creutzfeldt–Jakob disease

Creutzfeldt-Jakob disease (CJD) is a rare, fatal, neurodegenerative disease caused by a transmissible agent designated as proteinaceous infectious agent (prion). Searching for biochemical markers of CJD, we analysed cerebrospinal fluid (CSF) samples of 53 patients for tau-protein using an enzyme linked immunoassay (ELISA). In a group of 21 patients with definite CJD seen in the German case control study for CJD, tau-protein concentrations in CSF were significantly higher than in two control-groups of patients with other diseases (median 13,153 pg/ml, range 1,533-27,648 pg/ml; P = 0.0001). One group comprised 19 patients who were seen in the same study and were diagnosed as having other dementing diseases (tau concentration: median 558 pg/ml, range 233-1,769 pg/ml). The second control group comprised 13 patients from our hospital with no dementing disease (tau concentration: median 296 pg/ml, range 109-640 pg/ml). We conclude that determination of tau protein levels in CSF is a useful marker for laboratory diagnosis of CJD.

Value of CSF β-amyloid1-42 and tau as predictors of Alzheimer's disease in patients with mild cognitive impairment

Subjects with mild cognitive impairment (MCI) are at a high risk of developing clinical Alzheimers disease (AD). We asked to what extent the core biomarker candidates cerebro-spinal fluid (CSF) β-amyloid1–42 (Aβ1–42) and CSF tau protein concentrations predict conversion from MCI to AD. We studied 52 patients with MCI, 93 AD patients, and 10 healthy controls (HC). The MCI group was composed of 29 patients who had converted to AD during follow-up, and of 23 patients who showed no cognitive decline. CSF Aβ1–42 and tau protein levels were assessed at baseline in all subjects, using enzyme-linked immunosorbent assays. For assessment of sensitivity and specificity, we used independently established reference values for CSF Aβ1–42 and CSF tau. The levels of CSF tau were increased, whereas levels of Aβ1–42 were decreased in MCI subjects. Aβ1–42 predicted AD in converted MCI with a sensitivity of 59% and a specificity of 100% compared to HC. Tau yielded a greater sensitivity of 83% and a specificity of 90%. In a multiple Cox regression analysis within the MCI group, low baseline levels of Aβ1–42, but not other predictor variables (tau protein, gender, age, apolipoprotein E ɛ4 carrier status, Mini Mental Status Examination score, observation time, antidementia therapy), correlated with conversion status (P<0.05). Our findings support the notion that CSF tau and Aβ1–42 may be useful biomarkers in the early identification of AD in MCI subjects.

Neurochemical diagnosis of Alzheimer’s dementia by CSF Aβ42, Aβ42/Aβ40 ratio and total tau

Cerebrospinal fluid (CSF) concentrations of amyloid β peptides ending at positions 42 and 40 (Aβ42 and Aβ40, respectively), and total tau (tTau) protein were measured by ELISA in order to compare their accuracy in discriminating patients with Alzheimer’s disease (AD, n=22), non-Alzheimer dementia (nAD, n=11) and control subjects (CON, n=35). As compared to the other groups, the concentrations of Aβ42 and tTau were decreased (P<0.001) and increased (P<0.001) in AD, respectively, while Aβ40 did not differ significantly among the groups. Receiver operating characteristic (ROC) analysis was performed to define cut-off values for maximized sensitivity and specificity. For all groups compared the Aβ peptide ratio 42/40 classified more patients correctly, as compared to the concentration of Aβ42 alone: AD versus controls, 94 and 86.7%; AD versus nAD, 90 and 85% and AD versus nAD plus controls, 90.8 and 87%, respectively. The percentage of correctly classified patients was further improved when the Aβ ratio was combined with the analysis of the tTau concentration. Presence of the apolipoprotein E e4 allele, age or degree of mental disability did not significantly influence the parameters studied.

Large-scale, multicenter study of cerebrospinal fluid tau protein phosphorylated at serine 199 for the antemortem diagnosis of Alzheimer's disease

We surveyed a total of 570 cerebrospinal fluid (CSF) samples from a variety of diseases, including Alzheimers disease (AD; n = 236), non‐AD‐demented and nondemented diseases (n = 239), and normal controls (n = 95) to quantitate levels of tau protein phosphorylated at serine 199 (CSF/phospho‐tau199) by a recently established sandwich ELISA. The CSF/phospho‐tau199 levels in the AD group were significantly elevated compared to those in all the other non‐AD groups. Receiver operating characteristics curves showed that the diagnostic sensitivity and specificity for the AD group versus all the other non‐AD groups using the CSF/phospho‐tau199 were 85.2% and 85.0%, respectively. Furthermore, there was a significant positive correlation between CSF/phospho‐tau199 and CSF/total‐tau levels in the AD group. Elevated CSF/phospho‐tau199 in the AD group was noted irrespective of age, gender, dementia severity, and number of apolipoprotein E4 alleles. Thus, we suggest that CSF/phospho‐tau199 may be a novel and logical biomarker in supporting antemortem diagnosis of AD.

Phospho-tau/total tau ratio in cerebrospinal fluid discriminates Creutzfeldt–Jakob disease from other dementias

Early clinical symptoms of sporadic Creutzfeldt–Jakob disease (CJD) may overlap with other neurodegenerative diseases like Alzheimers disease (AD) and frontotemporal degeneration (FTD). On entering an era in which pharmaceutical treatment of CJD occurs, reliable diagnostic markers like immunodetection of 14–3–3 proteins in the cerebrospinal fluid (CSF) are required. However, false negative results in autopsy-proven, sporadic CJD cases, as well as false positive results in several other disorders including AD and FTD showing high CSF tau protein levels, limit the potential of this marker. Due to neuronal lysis the cytosolic fraction of total tau containing phosphorylated and non-phosphorylated isoforms is partially liberated into the CSF. Since hyperphosphorylation of tau may specifically occur in neurodegenerative diseases associated with neurofibrillary changes, we hypothesized that the phospho-tau (P-tau)/total tau ratio in CSF may be a useful marker to discriminate CJD from other neurodegenerative disorders. The P-tau/total tau ratio discriminated patients with CJD from all other neuro-degenerative disorders including patients with AD and FTD without any overlap. Although the results have to be confirmed in a larger sample, the preliminary data suggest that simultaneous measurement of total tau and P-tau in CSF may be useful to identify patients with CJD.

Consensus Paper of the WFSBP Task Force on Biological Markers of Dementia: The role of CSF and blood analysis in the early and differential diagnosis of dementia

Aging of population, and increasing life expectancy result in an increasing number of patients with dementia. This symptom can be a part of a completely curable disease of the central nervous system (e.g, neuroinflammation), or a disease currently considered irreversible (e.g, Alzheimers disease, AD). In the latter case, several potentially successful treatment approaches are being tested now, demanding reasonable standards of pre-mortem diagnosis. Cerebrospinal fluid and serum analysis (CSF/serum analysis), whereas routinely performed in neuroinflammatory diseases, still requires standardization to be used as an aid to the clinically based diagnosis of AD. Several AD-related CSF parameters (total tau, phosphorylated forms of tau, Aβ peptides, ApoE genotype, p97, etc.) tested separately or in a combination provide sensitivity and specificity in the range of 85%, the figure commonly expected from a good diagnostic tool. In this review, recently published reports regarding progress in neurochemical pre-mortem diagnosis of dementias are discussed with a focus on an early and differential diagnosis of AD. Novel perspectives offered by recently introduced technologies, e.g, fluorescence correlation spectroscopy (FCS) and surface enhanced laser desorption/ionization time-of-flight mass spectrometry (SELDI-TOF MS) are briefly discussed.

S-100 protein concentration in the cerebrospinal fluid of patients with Creutzfeldt-Jakob disease

Abstract We evaluated S-100 levels in paired cerebrospinal fluid (CSF) and serum samples in a group of 135 patients referred to the German Creutzfeldt-Jakob disease (CJD) surveillance unit from June 1993 to May 1995. The patients were seen in a prospective case control study. The diagnosis of probable CJD during life was made in any patient presenting with rapidly progressive dementia of less than 2 years’ duration, typical periodic sharp wave complexes (PSWCs) in the EEG and at least two of the following findings: myoclonus, visual/or cerebellar symptoms, pyramidal and/or extrapyramidal signs and/or akinetic mutism. Patients presenting with the above clinical signs and symptoms but without PSWCs were classified as possible, while those with a dementia of a duration exceeding 2 years and without PSWCs were classified as other. S-100 was determined in paired CSF and serum samples by a commercially available enzyme-linked immunosorbent assay. In a group of 76 patients with definite and probable CJD, S-100 concentration (median 25 ng/ml, range 2–117) in CSF was significantly higher (P < 0.0001) than in 32 patients diagnosed as other (median 4 ng/ml, range 1–19). Serum levels of S-100 were below 0.5 ng/ml in all groups. At a cut-off of 8 ng/ml an optimum sensitivity of 84.2% with a specificity of 90.6% for the diagnosis of CJD by the determination of S-100 in CSF is obtained. S-100 levels exceeding 8 ng/ml in CSF support the diagnosis of CJD in any patient presenting with rapidly progressive dementia.

Isoform Pattern of 14‐3‐3 Proteins in the Cerebrospinal Fluid of Patients with Creutzfeldt‐Jakob Disease

Abstract : Two‐dimensional polyacrylamide gel electrophoresis of CSF has been used in the diagnosis of Creutzfeldt‐Jakob disease (CJD). One of the two diagnostic protein spots was identified as isoform(s) of the 14‐3‐3 family of abundant brain proteins. This has led to the development of one‐dimensional 14‐3‐3 sodium dodecyl sulfate polyacrylamide gel electrophoresis immunoblot, which is currently used to support the diagnosis of CJD. In the present study employing western blot analysis, we have identified the panel of 14‐3‐3 isoforms that appear in the CSF of 10 patients with CJD compared with 10 patients with other dementias. The results clearly show that the 14‐3‐3 isoforms β, γ, ε, and η are present in the CSF of patients with CJD and can be used to differentiate other dementias. 14‐3‐3η also gave a baseline signal in all patients with other dementias, including six patients with Alzheimers disease. The presence of 14‐3‐3η in the CSF of a patient with herpes simplex encephalitis was particularly noteworthy. This study has determined that isoform‐specific 14‐3‐3 antibodies against β, γ, and ε should be considered for the neurochemical differentiation of CJD from other neurodegenerative diseases.

International quality control survey of neurochemical dementia diagnostics.

UNLABELLEDnCurrently, neurochemical dementia diagnostics (NDD) are increasingly entering routine clinical neurochemistry, offering improved early and differential diagnosis of dementias. However, there is an obvious lack of standardization in pre-analytical sample handling and systematic quality surveys. Therefore, in this study, 14 laboratories in Germany, Austria, and Switzerland were given aliquots of a human cerebrospinal fluid (CSF) sample, and were asked to measure Alzheimers disease (AD) biomarkers (amyloid beta (Abeta) peptides, total Tau protein, and phosphorylated Tau protein (P-tau(181P))) according to their routine protocols.nnnRESULTSnThe inter-laboratory coefficients of variation of the results obtained by the laboratories participating in this study were in the range of 20-30%. Although the results of this quality control survey are promising, the quality of measurements has to be further optimized.

β-amyloid peptides in cerebrospinal fluid of patients with Creutzfeldt–Jakob disease

Decreased levels of β‐amyloid peptide 1‐42 (Aβ1‐42) in cerebrospinal fluid (CSF) are a characteristic feature of Alzheimers disease (AD) but recently were also observed in Creutzfeldt–Jakob disease (CJD). We analyzed the CSF of patients with CJD, and AD and nondemented controls using a quantitative urea‐based Aβ sodium dodecyl sulfate polyacrylamide gel electrophoresis immunoblot. Like in AD and nondemented controls, we found a highly conserved pattern of carboxyterminally truncated Aβ1‐37/38/39 in addition to Aβ1‐40/42 also in CJD patients. By the introduction of the ratio Aβ1‐39 to Aβ1‐42, CJD and AD can effectively be differentiated. We conclude that the immunoblot shows disease‐specific CSF Aβ peptide patterns in CJD and AD and suppose that measurement of the Aβ peptide pattern seems to be a promising diagnostic tool in the differential diagnosis of dementias. Ann Neurol 2003;54:263–267