Desmoplakin as a potential candidate for cerebrospinal fluid marker to rule out 14-3-3 false positive rates in sporadic Creutzfeldt-Jakob disease differential diagnosis.

BACKGROUND: The detection of a 14-3-3 elevated level in cerebrospinal fluid (CSF) is a part of the diagnostic criteria for probable sporadic Creutzfeldt-Jakob disease (sCJD), as defined by the WHO. However, some pathological conditions associated with acute neuronal damage may result in a positive 14-3-3 test and thereby reduce test specificity in sCJD. OBJECTIVE: Desmoplakin has been previously identified as up-regulated CSF protein in sCJD and these studies aimed to investigate its diagnostic utility and compare it with two known CSF markers, 14-3-3 and tau. METHODS AND RESULTS: We tested CSF levels of 14-3-3, tau and desmoplakin in 58 sCJD patients and 81 control patients including 45 cases with an elevated 14-3-3 level due to other disease than sCJD. We detected an elevated CSF level of desmoplakin in 78% of the sCJD patients, while 14-3-3 (88%) and tau (91%) showed a higher positive rate. However, the false positive rate of newly tested desmoplakin was significantly lower in comparison to 14-3-3 and tau, and it accounted for only 11% versus 56% and 35%, respectively. Further reduction of false positive rates was achieved by combination of elevated tau level with a positive desmoplakin test. Moreover, in the non-sCJD group, desmoplakin level did not correlate with the level of both above-mentioned CSF markers, whereas a clear correlation was observed in the sCJD group. CONCLUSION: Desmoplakin showed a low positive rate accompanied by a very low false positive rate. Thus, we conclude that desmoplakin is a promising candidate for supportive CSF marker to rule out 14-3-3 false positive cases in sCJD differential diagnosis.

Possible editing of Alu transcripts in blood cells of sporadic Creutzfeldt-Jakob disease (sCJD).

Editing of RNA molecules gained major interest when coding mRNA was analyzed. A small, noncoding, Alu DNA element transcript that may act as regulatory RNA in cells was examined in this study. Alu DNA element transcription was determined in buffy coat from healthy humans and human sporadic Creutzfeldt-Jakob disease (sCJD) cases. In addition, non-sCJD controls, mostly dementia cases and Alzheimer's disease (AD) cases, were included. The Alu cDNA sequences were aligned to genomic Alu DNA elements by database search. A comparison of best aligned Alu DNA sequences with our RNA/cDNA clones revealed editing by deamination by ADAR (adenosine deaminase acting on RNA) and APOBEC (apolipoprotein B editing complex). Nucleotide exchanges like a G instead of an A or a T instead of a C in our cDNA sequences versus genomic Alu DNA pointed to recent mutations. To confirm this, our Alu cDNA sequences were aligned not only to genomic human Alu DNA but also to the respective genomic DNA of the chimpanzee and rhesus. Enhanced ADAR correlated with A-G exchanges in dementia, AD, and sCJD was noted when compared to healthy controls as well as APOBEC-related C-T exchanges. The APOBEC-related mutations were higher in healthy controls than in cases suffering from neurodegeneration, with the exception of the dementia group with the prion protein gene (PRNP) MV genotype. Hence, this study may be considered the first real-time analysis of Alu DNA element transcripts with regard to editing of the respective Alu transcripts in human blood cells.

Transcription of Alu DNA elements in blood cells of sporadic Creutzfeldt-Jakob disease (sCJD).

Alu DNA elements were long considered to be of no biological significance and thus have been only poorly defined. However, in the past Alu DNA elements with well-defined nucleotide sequences have been suspected to contribute to disease, but the role of Alu DNA element transcripts has rarely been investigated. For the first time, we determined in a real-time approach Alu DNA element transcription in buffy coat cells isolated from the blood of humans suffering from sporadic Creutzfeldt-Jakob disease (sCJD) and other neurodegenerative disorders. The reverse transcribed Alu transcripts were amplified and their cDNA sequences were aligned to genomic regions best fitted to database genomic Alu DNA element sequences deposited in the UCSC and NCBI data bases. Our cloned Alu RNA/cDNA sequences were widely distributed in the human genome and preferably belonged to the "young" Alu Y family. We also observed that some RNA/cDNA clones could be aligned to several chromosomes because of the same degree of identity and score to resident genomic Alu DNA elements. These elements, called paralogues, have purportedly been recently generated by retrotransposition. Along with cases of sCJD we also included cases of dementia and Alzheimer disease (AD). Each group revealed a divergent pattern of transcribed Alu elements. Chromosome 2 was the most preferred site in sCJD cases, besides chromosome 17; in AD cases chromosome 11 was overrepresented whereas chromosomes 2, 3 and 17 were preferred active Alu loci in controls. Chromosomes 2, 12 and 17 gave rise to Alu transcripts in dementia cases. The detection of putative Alu paralogues widely differed depending on the disease. A detailed data search revealed that some cloned Alu transcripts originated from RNA polymerase III transcription since the genomic sites of their Alu elements were found between genes. Other Alu DNA elements could be located close to or within coding regions of genes. In general, our observations suggest that identification and genomic localization of active Alu DNA elements could be further developed as a surrogate marker for differential gene expression in disease. A sufficient number of cases are necessary for statistical significance before Alu DNA elements can be considered useful to differentiate neurodegenerative diseases from controls.

Total prion protein levels in the cerebrospinal fluid are reduced in patients with various neurological disorders.

We performed a study on levels of the total prion protein (PrP) in humans affected by different neurological diseases and assessed the influence of several factors such as age, gender, and disease severity on the cerebrospinal fluid PrP levels. PrP-ELISA technique was used to analyze cerebrospinal fluid (CSF) samples. 293 CSF samples of patients with Creutzfeldt-Jakob-disease (CJD), Alzheimer's disease, dementia with Lewy-bodies, Parkinson's disease, multiple sclerosis, cerebral ischemia, generalized epileptic seizures, and meningitis and encephalitis in comparison to controls were analyzed. We found a significant reduction of CSF PrP levels in patients suffering from all neurodegenerative disorders analyzed. This group exhibited mean PrP values of 164 ng/ml while non-neurodegenerative disorder patients and healthy controls showed PrP levels of 208 ng/ml and 226 ng/ml, respectively. CSF levels correlated with disease severity in CJD, Alzheimer's disease, and dementia with Lewy-bodies. The finding of decreased PrP levels in the CSF of patients not only with CJD but also in other neurodegenerative disorders is intriguing. Age-, gender-, and genetic-specific factors might be involved in the PrP c regulation.

Brain-derived proteins in the CSF: do they correlate with brain pathology in CJD?

BACKGROUND: Brain derived proteins such as 14-3-3, neuron-specific enolase (NSE), S 100b, tau, phosphorylated tau and Abeta1-42 were found to be altered in the cerebrospinal fluid (CSF) in Creutzfeldt-Jakob disease (CJD) patients. The pathogenic mechanisms leading to these abnormalities are not known, but a relation to rapid neuronal damage is assumed. No systematic analysis on brain-derived proteins in the CSF and neuropathological lesion profiles has been performed. METHODS: CSF protein levels of brain-derived proteins and the degree of spongiform changes, neuronal loss and gliosis in various brain areas were analyzed in 57 CJD patients. RESULTS: We observed three different patterns of CSF alteration associated with the degree of cortical and subcortical changes. NSE levels increased with lesion severity of subcortical areas. Tau and 14-3-3 levels increased with minor pathological changes, a negative correlation was observed with severity of cortical lesions. Levels of the physiological form of the prion protein (PrPc) and Abeta1-42 levels correlated negatively with cortical pathology, most clearly with temporal and occipital lesions. CONCLUSION: Our results indicate that the alteration of levels of brain-derived proteins in the CSF does not only reflect the degree of neuronal damage, but it is also modified by the localization on the brain pathology. Brain specific lesion patterns have to be considered when analyzing CSF neuronal proteins.

Total tau protein, phosphorylated tau (181p) protein, beta-amyloid(1-42), and beta-amyloid(1-40) in cerebrospinal fluid of patients with dementia with Lewy bodies.

The intra vitam diagnosis of different dementias is still based on clinical grounds. So far, no technical investigations have been available to support these diagnoses. For tau protein and beta-amyloid(1-42) in cerebrospinal fluid (CSF), promising results for the diagnosis of Alzheimer's disease (AD) have been reported; however, their differential diagnostic spectrum is limited, as was recently shown for dementia with Lewy bodies (DLB) and for AD. Therefore, further marker proteins have to be established to ameliorate, support, and differentiate these clinical diagnoses. We evaluated beta-amyloid(1-40) and phosphorylated tau protein (181p), in addition to total tau protein and beta-amyloid(1-42), in 20 patients with DLB, 34 AD patients, and 20 non-demented neurological controls (NDCs). All markers could differentiate between the dementia groups (AD, DLB) and the controls. AD and DLB could be differentiated only by levels of total tau protein and by the ratio total tau protein/phosphorylated tau protein. However, values still overlapped markedly. In some cases, tau protein levels in CSF may contribute to the clinical distinction between DLB and AD, but the value of the markers is still limited, especially because of mixed pathology. We conclude that more specific markers have to be established to differentiate between these diseases.

Interleukin 4 and interleukin 10 levels are elevated in the cerebrospinal fluid of patients with Creutzfeldt-Jakob disease.

BACKGROUND: In neurodegenerative diseases, increasing attention has been focused on inflammatory mediators such as pro-inflammatory and anti-inflammatory cytokines and their potential influence in the process of neurodegeneration. In prion diseases, much data has been gained on the cell culture and animal disease models level, but only limited information is available on humans affected by Creutzfeldt-Jakob disease (CJD). OBJECTIVE: To obtain data on anti-inflammatory cytokines interleukin 4 and interleukin 10 in the cerebrospinal fluid of patients with CJD, patients with other dementia, and nondemented neurological patients and controls. DESIGN: Cerebrospinal fluid samples were collected from CJD patients and control subjects, and concentrations of the anti-inflammatory cytokines interleukin 4 and interleukin 10 were determined using an enzyme-linked immunosorbent assay. PATIENTS: Cerebrospinal fluid samples from 61 patients were analyzed. The group was composed of patients with CJD (n = 20), patients with other forms of dementia (n = 10), patients with motoneuron disease (n = 6), patients with normal pressure hydrocephalus (n = 5), and control subjects (n = 20). RESULTS: Interleukin 10 levels were significantly elevated in the cerebrospinal fluid of CJD patients (median, 9.8 pg/mL). The elevation was significant to other dementia (median, 7.9 pg/mL, P<.05), motoneuron disease (median, 7.9 pg/mL, P<.05), normal pressure hydrocephalus (median, 7.0 pg/mL, P<.05), and controls (median, 1.3 pg/mL, P<.001). Levels of interleukin 4 were significantly elevated in cerebrospinal fluid of patients with CJD (median, 26.4 pg/mL) compared with control subjects (median, 6.2 pg/mL, P<.001) and patients with a motoneuron disease (median, 10.5 pg/mL, P<.001) CONCLUSIONS: Elevated levels of the anti-inflammatory cytokines interleukin 4 and interleukin 10 in cerebrospinal fluid of patients with CJD are new findings. The data of the present study provide a clue toward the possible role of cytokines as immunological modifiers in the neurodegenerative process of CJD.

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

BACKGROUND: S-100B and tau protein have a high differential diagnostic potential for the diagnosis of Creutzfeldt-Jakob disease (CJD). So far there has been only limited information available about the dynamics of these parameters in the cerebrospinal fluid (CSF). However, there is a special interest in finding biochemical markers to monitor disease progression for differential diagnosis and treatment. PATIENTS AND METHODS: We analyzed CSF of 45 patients with CJD and of 45 patients with other neurological diseases for tau protein and S-100B in a follow-up setting. All diagnoses of CJD were later neuropathologically verified. A ratio between tau protein differences and the time between lumbar puncture was calculated. The same was done for S-100B. RESULTS: Tau protein levels of 34 cases were above the cut-off level for CJD (>1,300 pg/ml) in the first CSF sample. In 7 of 11 patients with lower tau levels in the first CSF sample, tau levels rose. The above-mentioned ratio was significantly higher in the CJD group than in the group with other neurological diseases. Similar results were obtained for S-100B. CONCLUSION: We conclude that follow-up investigations and calculation of ratios is a useful tool in the differential diagnosis of CJD. Variations in this pattern were observed in single cases.

Tau protein, Abeta42 and S-100B protein in cerebrospinal fluid of patients with dementia with Lewy bodies.

The intra vitam diagnosis of dementia with Lewy bodies (DLB) is still based on clinical grounds. So far no technical investigations have been available to support this diagnosis. As for tau protein and beta-amyloid(1-42) (Abeta42), promising results for the diagnosis of Alzheimer's disease (AD) have been reported; we evaluated these markers and S-100B protein in cerebrospinal fluid (CSF), using a set of commercially available assays, of 71 patients with DLB, 67 patients with AD and 41 nondemented controls (NDC) for their differential diagnostic relevance. Patients with DLB showed significantly lower tau protein values compared to AD but with a high overlap of values. More prominent differences were observed in the comparison of DLB patients with all three clinical core features and AD patients. Abeta42 levels were decreased in the DLB and AD groups versus NDC, without significant subgroup differences. S-100B levels were not significantly different between the groups. Tau protein levels in CSF may contribute to the clinical distinction between DLB and AD, but the value of the markers is still limited especially due to mixed pathology. We conclude that more specific markers have to be established for the differentiation of these diseases.

Serum tau protein level as a marker of axonal damage in acute ischemic stroke.

Biochemical markers of brain damage, e.g. ischemic stroke, should reflect the volume of irreversibly damaged brain parenchyma and the clinical outcome in a single patient in order to allow estimation of prognosis at an early stage. Tau protein, which derives predominantly from neurons and axons, is elevated in the cerebrospinal fluid of patients with neurodegenerative disease. This makes tau protein a potential marker of neuronal/axonal injury. In order to test this hypothesis, the current study aimed at showing that tau protein is measurable in the blood after acute ischemic stroke and that it correlates with clinical disability and stroke volume. In a longitudinal prospective study we measured tau protein serum levels with an ELISA in 30 patients longitudinally after ischemic stroke. Tau protein was detectable within 5 days after ischemia in the sera of 7/20 patients with MRI-proven infarction and in 2/10 patients with transitory ischemic attack; both of them had a small infarction visible on the MRI scan. Tau protein was measurable within 6 h after symptom onset, peaked after 3-5 days and correlated with infarct volume and disability after 3 months. In conclusion, serum tau protein is a candidate marker of axonal injury. In stroke, its clinical use is limited, because it is detectable only in a proportion of patients.