Follow-up investigations of tau protein and S-100B levels in cerebrospinal fluid of patients with Creutzfeldt-Jakob disease

Cerebrospinal Fluid Biomarker-Based Diagnosis of Sporadic Creutzfeldt-Jakob Disease: A Validation Study for Previously Established Cutoffs

BACKGROUND

Several biomarkers have been proposed to discriminate sporadic Creutzfeldt-Jakob disease (sCJD) from other dementias and control cases. However, their clinical accuracy depends on the PRNP codon 129 genotype, leaving it unclear how well established markers behave in untested conditions.

METHODS

We analyzed 14-3-3, tau, p-tau levels, and the p-tau/tau ratio in a population sample collected from Polish hospitals including nondementia, dementia, and definite sCJD cases and validated their parameters according to previously established cutoffs. Additionally, the correlation between biomarkers and disease duration as well as the influence of the PRNP129 polymorphism are reported.

RESULTS

The tau levels and p-tau/tau ratios differed considerably between sCJD and clinically characterized non-CJD cases (p < 0.001). p-tau was only elevated in sCJD when compared to cases without dementia (p < 0.05). Tau and the p-tau/tau ratio showed a sensitivity of 95 and 100%, respectively, in detecting sCJD cases. A negative correlation between tau levels and disease duration, but not the timing of lumbar puncture was observed.

CONCLUSION

The present findings confirmed the value of the p-tau/tau ratio as a robust sCJD biomarker and suggest a role for tau as prognostic marker.

Alternative application of Tau protein in Creutzfeldt-Jakob disease diagnosis: Improvement for weakly positive 14-3-3 protein in the laboratory

The 14-3-3 protein has been used as a biomarker for the diagnosis of sporadic Creutzfeldt-Jakob disease (sCJD). However, weakly positive 14-3-3 leads to false positive results and an incorrect diagnosis. We attempted to use quantitative data for tau protein to provide an accurate diagnosis based on weak 14-3-3 protein. Sixty-two patients with sCJD, including pathologically confirmed, clinically definite, and probable cases, and 89 non-CJD patients were investigated based on a Korean population. Among them, 20 sCJD and 14 non-CJD showed weakly positive 14-3-3. The total tau (t-tau) and phosphorylated tau (p-tau) protein levels were measured by ELISA, and the p-tau to t-tau ratio (p/t ratio) was calculated. The combined use of the 14-3-3 protein assay, t-tau levels, and p/t ratio improved the specificity of diagnosis compared with the use of the 14-3-3 protein assay alone (47% for 14-3-3 alone; 85.94% for 14-3-3 combined with t-tau; 90.62% for 14-3-3 combined with the p/t ratio). In addition, 18 of 20 sCJD and 12 of 14 non-CJD who were weakly positive for 14-3-3 were positive for the p/t ratio and negative for the p/t ratio, respectively. When used in combination with the 14-3-3 protein, the tau protein is useful as a biomarker for the precise diagnosis of sCJD.

Biomarkers in dementia: clinical utility and new directions

Imaging, cerebrospinal fluid (CSF) and blood-based biomarkers have the potential to improve the accuracy by which specific causes of dementia can be diagnosed in vivo, provide insights into the underlying pathophysiology, and may be used as inclusion criteria and outcome measures for clinical trials. While a number of imaging and CSF biomarkers are currently used for each of these purposes, this is an evolving field, with numerous potential biomarkers in varying stages of research and development. We review the currently available biomarkers for the three most common forms of neurodegenerative dementia, and give an overview of research techniques that may in due course make their way into the clinic.

Influence of the blood-CSF-barrier function on S100B in neurodegenerative diseases

OBJECTIVES

S100B was proposed to be a CSF and blood biomarker in a number of neurological diseases. The route of S100B to the CSF and the blood in neurodegenerative diseases is unclear. To assess the impact of the physiological or impaired blood-CSF-barrier (BCSFB) function on S100B concentrations in CSF and serum, we analysed S100B in correlation of the albumin quotient.

MATERIALS AND METHODS

S100Bserum and S100BCSF were quantified in samples from patients with a variety of neurological diseases using an immunoluminometric assay (Sangtec LIA-mat). Measures were analysed for a potential relation to the CSF/serum-albumin quotient (Qalb ), which indicates the BCSFB functionality.

RESULTS

We reasserted increased S100B concentrations in CSF and serum of CJD patients. Elevated S100Bserum correlated with elevated S100BCSF in all diagnoses but with exceptions. Neither S100BCSF nor S100Bserum did correlate with Qalb , even when the BCSFB function was progressively impaired as demonstrated by increased Qalb .

CONCLUSIONS

The lack of correlation between Qalb and S100BCSF is typically seen for proteins which are brain derived. Therefore, we propose that S100B enters the blood with the bulk flow via Pacchioni's granules and along the spinal nerve sheaths.

Tau and p-tau as CSF biomarkers in dementia: a meta-analysis

BACKGROUND

To evaluate the value of total tau (tau) and phosphorylated tau (p-tau) in cerebrospinal fluid (CSF) in the differential diagnosis of dementia, more specifically: dementia with Lewy Bodies (DLB), frontotemporal lobar degeneration (FTLD), vascular dementia (VaD), and Creutzfeldt-Jacob disease (CJD).

METHODS

A systematic literature search was performed to identify studies on tau and p-tau in DLB, FTLD, VaD and CJD. Tau concentrations were compared to healthy controls and to subjects with Alzheimer's disease (AD) using random effect meta-analysis. Outcome measures were Cohen's delta, sensitivity and specificity.

RESULTS

Compared to controls, tau concentrations are moderately elevated in DLB, FTLD and VaD, while p-tau concentrations are only slightly elevated in DLB and not elevated in FTLD and VaD. Compared to AD, lower tau concentrations differentiated DLB with a sensitivity of 73% and a specificity of 90%, FTLD with sensitivity and specificity of 74%, and VaD with a sensitivity of 73% and a specificity of 86%. Relative to AD, lower p-tau values differentiated FTLD with a sensitivity of 79% and specificity of 83%, and VaD with a sensitivity of 88% and a specificity of 78%. CJD is characterized by extremely elevated tau concentrations with a sensitivity of 91% and a specificity of 98% vs. AD.

CONCLUSIONS

CSF tau concentrations in DLB, FTLD and VaD are intermediate between controls and AD patients. Overlap with both controls and AD patients results in insufficient diagnostic accuracy, and the development of more specific biomarkers for these disorders is needed. CJD is characterized by extremely increased tau values, resulting in a sensitivity and specificity that exceeds 90%.

Variability in longitudinal cerebrospinal fluid tau and phosphorylated tau measurements

BACKGROUND

The influence of assay variation and duration of storage on changes in cerebrospinal fluid (CSF) levels of tau and phosphorylated (P)-tau with time was evaluated in 112 patients with various neurological disorders.

METHODS

These patients (aged 66+/-9 years, 52% male), referred to our memory clinic, underwent two spinal taps (mean interval 19 months) and the baseline samples were assayed twice in a sandwich enzyme-linked immunosorbent assay (ELISA): once after the first spinal tap (A1) and once in a separately stored aliquot (A2) simultaneous with the follow-up sample (B).

RESULTS

Coefficients of variances (CVs) of tau and P-tau levels determined in repeated spinal taps (DeltaB-A2) measured in one assay (10.9% and 7.6%) were lower (p<0.01) than the CVs observed in two different (DeltaB-A1) assays (16.5% and 11.7%). The CVs of tau and P-tau measurement of one CSF sample repeated on two occasions (DeltaA1-A2) were 12.3% and 8.6%. A difference in mean P-tau level was found if the same CSF samples were repeatedly measured in two different ELISAs (A1-A2).

CONCLUSIONS

Longitudinal CSF tau and P-tau are best measured in one assay resulting in a lower variability compared to measurement in two different assays. The within person variability in levels of these markers currently limits the use of these ELISAs in a longitudinal clinical setting.

Increased total-Tau levels in cerebrospinal fluid of pediatric hydrocephalus and brain tumor patients

Total Tau (t-Tau), hyperphosphorylated Tau (p-Tau(181P)) and beta-amyloid(1-42) in cerebrospinal fluid (CSF) have shown to be markers of neuronal and axonal degeneration in various neurological and neurodegenerative diseases. The aim of this study was to evaluate the influence of the presence of a brain tumor and hydrocephalus on t-Tau, p-Tau(181P) and beta-amyloid(1-42) levels in CSF of pediatric patients. t-Tau, p-Tau(181P) and beta-amyloid(1-42) levels were simultaneously quantified by xMAP technology in 22 lumbar and 15 ventricular CSF samples from newly diagnosed pediatric brain tumor patients and 39 lumbar and 12 ventricular CSF samples from pediatric patients without a brain tumor. t-Tau, p-Tau(181P) and beta-amyloid(1-42) levels in both lumbar and ventricular CSF were not significantly correlated with age. t-Tau levels in lumbar CSF were elevated in brain tumor patients, being especially high in medulloblastoma patients. Lumbar CSF p-Tau(181P) levels were lower in brain tumor patients compared to normal controls. Ventricular levels of t-Tau, p-Tau(181P) and beta-amyloid(1-42) were not significantly different between the brain tumor patients and non-tumor patients, but t-Tau levels were significantly increased in patients with radiological signs of hydrocephalus. Two patients with an infected ventriculo-peritoneal drain also had high CSF t-Tau levels. In conclusion, high t-Tau levels in CSF are found in pediatric patients with a brain tumor, patients with hydrocephalus and patients with a serious CNS infection, reflecting neuronal and axonal damage. Ongoing studies should determine whether these neurodegenerative markers in CSF can be used to monitor neuronal and axonal degeneration in these patients during therapy and long-term follow up.

Rapidly progressive dementia

In contrast with more common dementing conditions that typically develop over years, rapidly progressive dementias can develop subacutely over months, weeks, or even days and be quickly fatal. Because many rapidly progressive dementias are treatable, it is paramount to evaluate and diagnose these patients quickly. This review summarizes recent advances in the understanding of the major categories of RPD and outlines efficient approaches to the diagnosis of the various neurodegenerative, toxic-metabolic, infectious, autoimmune, neoplastic, and other conditions that may progress rapidly.

Chronological changes in MRI and CSF biochemical markers in Creutzfeldt-Jakob disease patients

BACKGROUND

There are currently no markers for evaluating chronological changes in Creutzfeldt-Jakob disease (CJD). We examined if chronological changes in biochemical markers in cerebrospinal fluid (CSF) and diffusion-weighted magnetic resonance imaging (DWI) were utilizable for this purpose.

METHODS

Ten independent patients were divided into two groups of 5 patients each. We analyzed CSF biochemical markers, DWI and the clinical course in one group. In the remaining group, only the CSF biochemical markers were analyzed before and after the onset of akinetic mutism.

RESULTS

The level of total tau (t-tau) protein in CSF in the early phase after disease onset was 2,655 +/- 423.9 pg/ml, reaching a mean peak of 14,675 +/- 1,240 pg/ml in the middle phase and gradually declining after that. Just before patients deteriorated into akinetic mutism, t-tau protein titers reached a maximum (8,786 +/- 2,975 pg/ml). There were dramatic changes in t-tau protein levels throughout the clinical course, unlike the other markers. DWI was not always utilizable, because of discordance with clinical symptoms seen in this study. Four cases exhibited peaks in t-tau protein levels while the patients fell into akinetic mutism except 1 case.

CONCLUSION

Our results suggest that t-tau protein is the most sensitive marker of disease progression in CJD patients.