Diagnostic value of CSF protein profile in a Portuguese population of sCJD patients

A case report of fatal familial insomnia with cerebrospinal fluid leukocytosis during the COVID-19 epidemic and review of the literature

Fatal familial insomnia (FFI) is a rare autosomal dominant genetic neurodegenerative disease. Generally, FFI patients will develop rapidly progressive dementia, sleep disturbance, autonomic dysfunction, and so on. Cerebrospinal fluid examination of FFI patients normally shows no obvious abnormalities. Here, we report a young male patient who was diagnosed with FFI during the COVID-19 epidemic. Clinical symptoms include psychobehavioral abnormality, cognitive decline, sleep disturbance, and autonomic dysfunction. No abnormalities were found in routine examinations after admission. However, the number of white blood cells in the cerebrospinal fluid increased. Though the patient was treated with anti-infection and immunotherapy, the symptoms were not relieved. A lumbar puncture was performed again, and it was found that the total Tau protein in the cerebrospinal fluid was elevated, and PET results showed that brain metabolism decreased. Finally, a genetic test was used to confirm the diagnosis of FFI. This case suggests that patients with FFI may also have elevated white blood cells in cerebrospinal fluid and timely detection of Tau protein in cerebrospinal fluid is helpful for early identification of FFI. And precise diagnosis relies on genetic testing.

Associations between self-reported sleep quality and cerebrospinal fluid biomarkers in mild cognitive impairment and Alzheimer's disease

Sleep disorders are very common in mild cognitive impairment (MCI) and Alzheimer's disease (AD). Several parameters of polysomnography seem to correlate with cognitive scores and amyloid biomarkers in the different stages of AD. However, there is limited evidence for the relationship between self-reported sleep impairment and disease biomarkers. In this study, we assessed the relationship between self-reported sleep complaints, with the Pittsburgh Sleep Quality Index, and both cognitive function and cerebrospinal fluid biomarkers in 70 patients with MCI and 78 patients with AD. Sleep duration and daytime dysfunction were higher in AD. Daytime dysfunction had a negative correlation with cognitive scores (Mini-Mental-State Examination and Montreal Cognitive Assessment) and with amyloid-beta1-42 protein, and a positive correlation with total tau protein. However, daytime dysfunction was an independent predictor only of t-tau values (F=57.162; 95% CI: [18.118; 96.207], P=0.004). These findings support a relationship between daytime dysfunction, cognitive scores and neurodegeneration, further expanding recent findings that it may signal a risk of dementia.

Whole-exome sequencing reveals PSEN1 and ATP7B combined variants as a possible cause of early-onset Lewy body dementia: a case study of genotype-phenotype correlation

Dementia with Lewy bodies is a neurodegenerative disease, sharing features with Parkinson's and Alzheimer's diseases. We report a case of a patient dementia with Lewy bodies carrying combined PSEN1 and ATP7B mutations. A man developed dementia with Lewy bodies starting at the age of 60 years. CSF biomarkers were of Alzheimer's disease and DaTSCAN was abnormal. Whole-exome sequencing revealed a heterozygous p.Ile408Thr PSEN1 variant and a homozygous p.Arg616Trp ATP7B variant. This case reinstates the need of considering ATP7B mutations when evaluating a patient with parkinsonism and supports p.Ile408Thr as a pathogenic PSEN1 variant.

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.

Could Sporadic Creutzfeldt-Jakob Disease Be Underdiagnosed in China? Experience From Four Cases

Background: Creutzfeldt-Jakob Disease (CJD) is a rapidly progressive neurodegenerative disease caused by the misfolded version of the cellular prion protein. Here we report four cases of sporadic CJD (sCJD) and describe the diagnostic methods available in order avoid missed or delayed recognition of CJD in China.

Case presentation: We report four patients diagnosed with sCJD between March 2018 and December 2019 at Xiangya Hospital and the Second Xiangya Hospital of Central South University. All patients were admitted to the hospital because of a progressive cognitive decline. Although their routine tests and biochemical indicators in the cerebrospinal fluid (CSF), as well as computed tomography (CT) imaging, did not reveal any apparent abnormalities, the presence of “cortical ribboning” was incidentally found on diffusion-weighted imaging (DWI). The patients were subsequently diagnosed with CJD based on positive testing for 14-3-3 protein in their CSF, and the presence of periodic sharp and slow wave complexes (PSWCs) on their electroencephalograms (EEG). Additionally, two of patients was confirmed pathological examination of cerebral biopsies demonstrating neuronal loss, gliosis, and spongiform changes.

Conclusions: CJD is a rare disease and is easily misdiagnosed by clinician in China due to a lack of recognition and awareness of CJD. Based on our experience described in this report, enhanced vigilance for CJD is required for patients with rapidly progressive dementia in China and other developing countries. DWI, EEG and detection of 14-3-3 protein in CSF should be performed in order to achieve a timely diagnosis of CJD.

An automated alert system based on the p-Tau/Tau ratio to quickly inform health professionals upon a suspected case of sporadic Creutzfeldt-Jakob disease

INTRODUCTION

Knowing the risk of potential sporadic Creutzfeldt-Jakob disease (sCJD) instrument-contamination is essential in hospitals. We examined the relevance of the p-Tau/Tau ratio to exclude a probable case of sCJD in clinical practice, and we established an alert system to quickly inform health professionals in case of positivity.

METHODS

This retrospective study was conducted on 143 cerebrospinal fluid samples from patients suspected for sCJD. The distinction between probable cases of sCJD and other patients was based on clinical, paraclinical and biological (14-3-3, Tau, p-Tau, Aβ _1-42) data. From this experience, the health professionals developed an alert system to be implemented upon a suspected case of sCJD.

RESULTS

A significant decrease in p-Tau/Tau ratio between sCJD and the other diseases was observed (p < 0 .001). The combined Tau test presented a sensitivity higher than 14-3-3 (100% versus 92.3%, p =0 .006) and an equivalent specificity (90% versus 96.1%). The time required for obtaining results was higher for 14-3-3 due to the centralization of investigations in some laboratories (3 weeks versus 2 h). In the presence of these elements, the triggering of the alert system was based on the p-Tau/Tau ratio. This system involves sending an automatic mail to the hospital department involved in the patient's care and the hospital hygiene team, which oversees the application of the procedures.

CONCLUSION

The p-Tau/Tau concentrations present the desired criteria for use in current medical practice to fight against iatrogenic transmission. The alert system confirms a probable case of sCJD instantly to health professionals. Hygiene and sterilization measures can be applied immediately.

Association between Adipokines and Biomarkers of Alzheimer's Disease: A Cross-Sectional Study

BACKGROUND

Adipose tissue dysfunction has been implicated in the pathophysiology of Alzheimer's disease. However, the involvement of adipokines, particularly adiponectin, remains unclear.

OBJECTIVE

To compare serum and cerebrospinal fluid (CSF) levels of adiponectin, leptin and leptin-to-adiponectin ratio in patients within the spectrum of Alzheimer's disease and evaluate their relationship with classical biomarkers and their value as markers of progression.

METHODS

Amnestic mild cognitive impairment (MCI, n = 71) and Alzheimer's dementia (AD, n = 53) subjects were consecutively recruited for serum and CSF adiponectin and leptin determination using an analytically validated commercial enzyme-linked immunosorbent assay (ELISA). Correlations were explored using adjusted Spearman's correlation coefficients. A logistic regression model and ROC analysis were performed to evaluate the staging predictive value of adipokines.

RESULTS

Serum adiponectin was 33% higher in AD when compared to MCI patients. Adiponectin CSF levels, similar in both groups, were positively correlated with Aβ42 and cognitive function, though only in women. The area under the ROC curve was 0.673 (95% CI:0.57-0.78) for serum adiponectin as predictor of dementia stage and the cut-off 10.85μg/ml maximized the sum of specificity (87%) and sensitivity (44%).

CONCLUSION

Although longitudinal studies are required, we hypothesize that higher serum adiponectin in AD patients constitutes a strategy to compensate possible central signaling defects. In addition, adiponectin might be specifically assigned to neuroprotective functions in women and eventually involved in the female-biased incidence of Alzheimer's disease.

Lower CSF Amyloid-Beta1-42 Predicts a Higher Mortality Rate in Frontotemporal Dementia

Frontotemporal lobar degeneration, the neuropathological substrate of frontotemporal dementia (FTD), is characterized by the deposition of protein aggregates, including tau. Evidence has shown concomitant amyloid pathology in some of these patients, which seems to contribute to a more aggressive disease. Our aim was to evaluate cerebrospinal fluid (CSF) amyloid-beta as a predictor of the mortality of FTD patients. We included 99 patients diagnosed with FTD—both behavioral and language variants—with no associated motor neuron disease, from whom a CSF sample was collected. These patients were followed prospectively in our center, and demographic and clinical data were obtained. The survival analysis was carried through a Cox regression model. Patients who died during follow up had a significantly lower CSF amyloid-beta_1–42 than those who did not. The survival analysis demonstrated that an increased death rate was associated with a lower CSF amyloid-beta_1–42 (HR = 0.999, 95% CI = [0.997, 1.000], p = 0.049). Neither demographic nor clinical variables, nor CSF total tau or p-tau were significantly associated with this endpoint. These results suggest that amyloid deposition in FTD patients may be associated with a higher mortality.

Increased CSF tau is associated with a higher risk of seizures in patients with Alzheimer's disease

INTRODUCTION

Neurofibrillary tangles and tau protein, the neuropathological hallmarks of Alzheimer's disease (AD), have been identified in patients with epilepsy. Tau protein was also associated with the modulation of neuronal excitability in animal models of AD.

MATERIALS AND METHODS

We evaluated in 292 patients with AD the association between the risk of seizure development and AD cerebrospinal fluid (CSF) biomarkers, demographic characteristics, baseline Mini-Mental State Examination (MMSE) score, comorbidities, and apolipoprotein E status.

RESULTS

The development of seizures was associated with younger age at dementia's onset, lower baseline MMSE, and higher CSF total tau protein levels, but only MMSE (hazard ratio [HR] = 0.935; 95% confidence interval [CI] = [0.903, 0.968]; p < 0.001) and CSF tau (HR = 1.001; 95%CI = [1.001, 1.002]; p = 0.001) were independent predictors on multivariate analysis.

DISCUSSION

While CSF tau and lower baseline MMSE association with seizure development could in part be explained by a greater degree of cortical damage, the role of tau in the modulation of neuronal excitability may also play a role and should be further investigated.

Added Diagnostic Value of Cerebrospinal Fluid Biomarkers for Differential Dementia Diagnosis in an Autopsy-Confirmed Cohort

Background:

Differential dementia diagnosis remains a challenge due to overlap of clinical profiles, which often results in diagnostic doubt.

Objective:

Determine the added diagnostic value of cerebrospinal fluid (CSF) biomarkers for differential dementia diagnosis as compared to autopsy-confirmed diagnosis.

Methods:

Seventy-one dementia patients with autopsy-confirmed diagnoses were included in this study. All neuropathological diagnoses were established according to standard neuropathological criteria and consisted of Alzheimer’s disease (AD) or other dementias (NONAD). CSF levels of Aβ_1 - 42, T-tau, and P-tau₁₈₁ were determined and interpreted based on the IWG-2 and NIA-AA criteria, separately. A panel of three neurologists experienced with dementia made clinical consensus dementia diagnoses. Clinical and CSF biomarker diagnoses were compared to the autopsy-confirmed diagnoses.

Results:

Forty-two patients (59%) had autopsy-confirmed AD, whereas 29 patients (41%) had autopsy-confirmed NONAD. Of the 24 patients with an ambiguous clinical dementia diagnosis, a correct diagnosis would have been established in 67% of the cases applying CSF biomarkers in the context of the IWG-2 or the NIA-AA criteria respectively.

Conclusion:

AD CSF biomarkers have an added diagnostic value in differential dementia diagnosis and can help establishing a correct dementia diagnosis in case of ambiguous clinical dementia diagnoses.

A systematic review comparing the diagnostic value of 14-3-3 protein in the cerebrospinal fluid, RT-QuIC and RT-QuIC on nasal brushing in sporadic Creutzfeldt-Jakob disease

BACKGROUND

Sporadic Creutzfeldt-Jakob disease (sCJD) is a human prion disease that is a relatively common differential diagnosis in dementia patients. Therefore it needs a good diagnostic tool. Brain autopsy is the golden standard for the diagnosis of CJD; however, a less invasive technique is 14-3-3 protein measurement in the cerebrospinal fluid (CSF). In this systematic review, we compared the diagnostic value of the 14-3-3 protein measurement to the newer RT-QuIC test and a variant of RT-QuIC where nasal brushing is used to collect the samples.

METHODS

The search via MeSH terms and quality assessment was carried out by two individual researchers.

RESULTS

In 14-3-3 and RT-QuIC the sensitivity was comparable, respectively, 88% and 86%. Specificity however was higher in RT-QuIC 99.5% compared to 80% in 14-3-3. Nasal brushing showed the best results with a sensitivity of 97% and a specificity of 100%.

CONCLUSION

Nasal brushing, despite being the best diagnostic tool according to the data, needs more study since there has only been a few studies regarding the technique. It is safe to say that due to the high specificity, RT-QuIC is superior to 14-3-3 testing.

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.

Prion-specific and surrogate CSF biomarkers in Creutzfeldt-Jakob disease: diagnostic accuracy in relation to molecular subtypes and analysis of neuropathological correlates of p-tau and Aβ42 levels

The differential diagnosis of Creutzfeldt-Jakob disease (CJD) from other, sometimes treatable, neurological disorders is challenging, owing to the wide phenotypic heterogeneity of the disease. Real-time quaking-induced prion conversion (RT-QuIC) is a novel ultrasensitive in vitro assay, which, at variance with surrogate neurodegenerative biomarker assays, specifically targets the pathological prion protein (PrP^Sc). In the studies conducted to date in CJD, cerebrospinal fluid (CSF) RT-QuIC showed good diagnostic sensitivity (82–96%) and virtually full specificity. In the present study, we investigated the diagnostic value of both prion RT-QuIC and surrogate protein markers in a large patient population with suspected CJD and then evaluated the influence on CSF findings of the CJD type, and the associated amyloid-β (Aβ) and tau neuropathology. RT-QuIC showed an overall diagnostic sensitivity of 82.1% and a specificity of 99.4%. However, sensitivity was lower in CJD types linked to abnormal prion protein (PrP^Sc) type 2 (VV2, MV2K and MM2C) than in typical CJD (MM1). Among surrogate proteins markers (14-3-3, total (t)-tau, and t-tau/phosphorylated (p)-tau ratio) t-tau performed best in terms of both specificity and sensitivity for all sCJD types. Sporadic CJD VV2 and MV2K types demonstrated higher CSF levels of p-tau when compared to other sCJD types and this positively correlated with the amount of tiny tau deposits in brain areas showing spongiform change. CJD patients showed moderately reduced median Aβ42 CSF levels, with 38% of cases having significantly decreased protein levels in the absence of Aβ brain deposits. Our results: (1) support the use of both RT-QuIC and t-tau assays as first line laboratory investigations for the clinical diagnosis of CJD; (2) demonstrate a secondary tauopathy in CJD subtypes VV2 and MV2K, correlating with increased p-tau levels in the CSF and (3) provide novel insight into the issue of the accuracy of CSF p-tau and Aβ42 as markers of brain tauopathy and β-amyloidosis.

Cerebrospinal Fluid Biomarkers in the Diagnosis of Creutzfeldt-Jakob Disease in Slovak Patients: over 10-Year Period Review

Creutzfeldt-Jakob disease is a rare, but rapidly progressive, up to now untreatable and fatal neurodegenerative disorder. Clinical diagnosis of Creutzfeldt-Jakob disease (CJD) is difficult; however, it can be facilitated by suitable biomarkers. Aim of the present study is to compare levels of cerebrospinal fluid biomarkers (total tau protein, phosphorylated-tau protein, protein 14-3-3 and amyloid beta) in Slovak population of CJD suspect cases, retrospectively in over a 10-year period. One thousand three hundred sixty-four CSF samples from patients with suspect CJD, forming a homogenous group in terms of geographical as well as of equal transport conditions, storage and laboratory processing, were analysed. Definite diagnosis of Creutzfeldt-Jakob disease was confirmed in 101 patients with genetic form, and 60 patients with its sporadic form of the disease. Specificity of protein 14-3-3 and total tau in both forms CJD was similar (87 % for P14-3-3/85 % for total tau), sensitivity to P 14-3-3 and total tau was higher in sporadic Creutzfeldt-Jakob disease (sCJD) (90/95 %) than in genetic Creutzfeldt-Jakob disease (gCJD) (89/74 %). As expected, the total tau levels were significantly higher in CJD patients than in controls, but there was also significant difference between gCJD and sCJD (levels in gCJD were lower; p = 0.003). There was no significant difference in p-tau and Aβ 1-42 levels neither between both CJD forms nor between CJD patients and control group.

Prognosis of Early-Onset vs. Late-Onset Mild Cognitive Impairment: Comparison of Conversion Rates and Its Predictors

BACKGROUND

Despite having the same histopathological characteristics, early-onset and late-onset Alzheimer's disease (AD) patients show some distinct clinical and neuropsychological profiles. Early Onset Mild Cognitive Impairment (EOMCI) is a less characterized group. The aim of this study is to characterize MCI probably due to AD in terms of the clinical, genetic, Cerebrospinal fluid (CSF) biomarkers profile and conversion rate of EOMCI, compared to the late-onset form (LOMCI).

METHODS

159 MCI patients were divided in two groups: 52 EOMCI (onset < 65 years) and 107 LOMCI (onset ≥ 65 years). We investigated differences in neuropsychological scores, clinical variables, ApoE genotype, CSF biomarkers (Aβ42, t-Tau and p-Tau) in both groups. Conversion was ascertained during follow-up.

RESULTS

EOMCI showed a longer duration of symptoms prior to the first evaluation (EOMCI = 4.57 vs. LOMCI = 3.31, p = 0.008) and scored higher on the subjective memory complaints scale (9.91 vs. 7.85, p = 0.008), but performed better in brief cognitive tests (27.81 vs. 26.51, p < 0.001 in Mini-Mental State Examination; 19.84 vs. 18.67, p = 0.005 in Montreal Cognitive Assessment) than LOMCI. ApoE genotype distribution and CSF biomarker profile were similar in both groups, as was the conversion risk. Lower Aβ42 (Hazard ratio (HR): 0.998, 95% Confidence Interval (CI) = [0.996⁻1.000], p = 0.042), higher t-Tau levels (HR: 1.003, 95%CI = [1.000⁻1.005], p = 0.039) and higher scores in the Alzheimer Disease Assessment Scale-Cognitive (HR: 1.186, 95%CI = [1.083⁻1.299], p = 0.002) increased the risk of conversion.

DISCUSSION

Despite differences in memory performance and memory complaints, EOMCI and LOMCI seem to represent indistinct biological groups that do not have a higher risk of conversion to AD or differ in risk factors for conversion.

Sporadic Creutzfeldt-Jakob disease diagnostic accuracy is improved by a new CSF ELISA 14-3-3γ assay

Protein 14-3-3 is a reliable marker of rapid neuronal damage, specifically increased in cerebrospinal fluid (CSF) of sporadic Creutzfeldt-Jakob disease (sCJD) patients. Its detection is usually performed by Western Blot (WB), prone to methodological issues. Our aim was to evaluate the diagnostic performance of a recently developed quantitative enzyme-linked immunosorbent (ELISA) assay for 14-3-3γ, in comparison with WB and other neurodegeneration markers. CSF samples from 145 patients with suspicion of prion disease, later classified as definite sCJD (n=72) or Non-prion diseases (Non-CJD; n=73) comprised our population. 14-3-3 protein was determined by WB and ELISA. Total Tau (t-Tau) and phosphorylated Tau (p-Tau) were also evaluated. Apolipoprotein E gene (ApoE) and prionic protein gene (PRNP) genotyping was assessed. ELISA 14-3-3γ levels were significantly increased in sCJD compared to Non-CJD patients (p<0.001), showing very good accuracy (AUC=0.982; sensitivity=97%; specificity=94%), and matching WB results in 81% of all cases. It strongly correlated with t-Tau and p-Tau (p<0.0001), showing slightly higher specificity (14-3-3 WB - 63%; Tau - 90%; p-Tau/t-Tau ratio - 88%). From WB inconclusive results (n=44), ELISA 14-3-3γ correctly classified 41 patients. Additionally, logistic regression analysis selected ELISA 14-3-3γ as the best single predictive marker for sCJD (overall accuracy=93%). ApoE and PRNP genotypes did not influence ELISA 14-3-3γ levels. Despite specificity for 14-3-3γ isoform, ELISA results not only match WB evaluation but also help discrimination of inconclusive results. Our results therefore reinforce this assay as a single screening test, allowing higher sample throughput and unequivocal results.

Characteristics of Korean patients with suspected Creutzfeldt-Jakob disease with 14-3-3 protein in cerebrospinal fluid: Preliminary study of the Korean Creutzfeldt-Jakob disease active surveillance program

Although Korea had a national surveillance system for Creutzfeldt-Jakob disease (CJD), it was mainly dependent on attending physician's reports. Thus, little prospective data about the epidemiology, characteristics, and final diagnoses of suspected patients were available. We have established a nationwide network for the active surveillance of patients with suspected CJD. When the requested cerebrospinal fluid (CSF) samples tested positive for 14-3-3 protein, we investigated the clinical characteristics of the corresponding patients and followed them until their final diagnoses were confirmed. A total of 218 samples were requested for CSF assays from May 2010 to August 2012, and 106 (48.6%) were positive for 14-3-3 protein. In 89 patients with complete clinical data, 38 (42.7%) were diagnosed with probable CJD and the estimated annual occurrence of CJD was 16.3 persons-per-year. The most common diagnoses of the remainder were central nervous system infection and any-cause encephalopathy. Non-CJD subjects showed worse initial consciousness levels than CJD patients. This preliminary study showed that the number of reported cases of CJD and the true positivity rates of CSF 14-3-3 protein assays were both low in Korea. An active surveillance system is urgently needed to provide the latest nationwide epidemiological data of CJD.

Proteomics applications in prion biology and structure

Prion diseases are a heterogeneous class of fatal neurodegenerative disorders associated with misfolding of host cellular prion protein (PrP(C)) into a pathological isoform, termed PrP(Sc). Prion diseases affect various mammals, including humans, and effective treatments are not available. Prion diseases are distinguished from other protein misfolding disorders - such as Alzheimer's or Parkinson's disease - in that they are infectious. Prion diseases occur sporadically without any known exposure to infected material, and hereditary cases resulting from rare mutations in the prion protein have also been documented. The mechanistic underpinnings of prion and other neurodegenerative disorders remain poorly understood. Various proteomics techniques have been instrumental in early PrP(Sc) detection, biomarker discovery, elucidation of PrP(Sc) structure and mapping of biochemical pathways affected by pathogenesis. Moving forward, proteomics approaches will likely become more integrated into the clinical and research settings for the rapid diagnosis and characterization of prion pathogenesis.

Cerebrospinal fluid Aβ40 is similarly reduced in patients with Frontotemporal Lobar Degeneration and Alzheimer's Disease

Cerebrospinal fluid (CSF) biomarkers have been increasingly studied for dementia diagnosis, however the accuracy to distinguish between different forms of dementia is still unsatisfactory. In this study, the added value of another CSF Aβ-peptide (Aβ40), along with the core CSF markers t-Tau, p-Tau, and Aβ42, in the discrimination between two large dementia groups of Frontotemporal Lobar Degeneration (FTLD; n=107), Alzheimer's Disease (AD; n=107) and non-demented subjects (n=33) was evaluated. In FTLD, t-Tau and p-Tau were significantly increased in relation to controls, but lower than in AD, while Aβ42 was similar in FTLD and controls, but higher than in AD. Equally reduced Aβ40 levels were seen in both dementia groups, and therefore the combination of Aβ40 with core CSF biomarkers optimally discriminated FTLD and AD patients from controls. Aβ42 and t-Tau were selected as the best biomarker subset to differentiate FTLD from AD, with no added value of Aβ40 to the model. Diagnostic accuracy between FTLD and AD was still sub-optimal, with a significant percentage (23%) of FTLD patients, in particularly women, carrying an ApoE-ε4 allele, showing a CSF-AD biomarkers profile. Although CSF Aβ40 does not appear to have an additional value in the distinction between FTLD and AD, it increases the discrimination between subjects with dementia from controls. A CSF-AD biomarker profile can be seen in patients with a clinical phenotype of FTLD, reinforcing the need for autopsy confirmation.

Oxidative stress involving changes in Nrf2 and ER stress in early stages of Alzheimer's disease

Oxidative stress and endoplasmic reticulum (ER) stress have been associated with Alzheimer's disease (AD) progression. In this study we analyzed whether oxidative stress involving changes in Nrf2 and ER stress may constitute early events in AD pathogenesis by using human peripheral blood cells and an AD transgenic mouse model at different disease stages. Increased oxidative stress and increased phosphorylated Nrf2 (p(Ser40)Nrf2) were observed in human peripheral blood mononuclear cells (PBMCs) isolated from individuals with mild cognitive impairment (MCI). Moreover, we observed impaired ER Ca2+ homeostasis and increased ER stress markers in PBMCs from MCI individuals and mild AD patients. Evidence of early oxidative stress defense mechanisms in AD was substantiated by increased p(Ser40)Nrf2 in 3month-old 3xTg-AD male mice PBMCs, and also with increased nuclear Nrf2 levels in brain cortex. However, SOD1 protein levels were decreased in human MCI PBMCs and in 3xTg-AD mice brain cortex; the latter further correlated with reduced SOD1 mRNA levels. Increased ER stress was also detected in the brain cortex of young female and old male 3xTg-AD mice. We demonstrate oxidative stress and early Nrf2 activation in AD human and mouse models, which fails to regulate some of its targets, leading to repressed expression of antioxidant defenses (e.g., SOD-1), and extending to ER stress. Results suggest markers of prodromal AD linked to oxidative stress associated with Nrf2 activation and ER stress that may be followed in human peripheral blood mononuclear cells.

Comparing CSF biomarkers and brain MRI in the diagnosis of sporadic Creutzfeldt-Jakob disease

We assessed the diagnostic utility of 3 CSF biomarkers-14-3-3 protein, total tau (T-tau), and neuron-specific enolase (NSE)-from the same lumbar puncture to distinguish between participants with neuropathologically confirmed sporadic Creutzfeldt-Jakob disease (sCJD, n = 57) and controls with nonprion rapidly progressive dementia (npRPD, n = 41). Measures of diagnostic accuracy, sensitivity, specificity, positive predictive value, and negative predictive value, as well as logistic regression and area under the receiver operator curve (AUC), were used to assess the ability of these CSF biomarkers, alone or concomitantly, to predict diagnosis. In a subcohort with available MRI (sCJD n = 57, npRPD = 32), we compared visual assessment of diffusion-weighted imaging MRI sequences to these CSF biomarkers. MRI was the best predictor, with an AUC of 0.97 (confidence interval [CI] 0.92-1.00) and a diagnostic accuracy of 97% (CI 90%-100%). Of the CSF biomarkers, T-tau had a higher diagnostic accuracy (79.6%) than 14-3-3 (70.4%, CI for difference 8.7%, 9.7%; p = 0.048) or NSE (71.4%, CI for difference 7.6%, 8.7%; p = 0.03).

Review: Laboratory diagnosis and surveillance of Creutzfeldt-Jakob disease

Creutzfeldt-Jakob disease (CJD) is a representative human transmissible spongiform encephalopathy associated with central nervous system degeneration. Prions, the causative agents of CJD, are composed of misfolded prion proteins and are able to self-replicate. While CJD is a rare disease affecting only 1-1.5 people per million worldwide annually, it has attracted both scientific and public attention as a threatening disease since an epidemic of variant CJD (vCJD) cases appeared in the mid-1990s. Due to its unconventional transmission and invariable fatality, CJD poses a serious risk to public health. The hundreds of sporadic, genetic, and iatrogenic CJD cases as well as potential zoonotic transmission suggest that CJD is an ongoing concern for the field of medicine. Nevertheless, treatment aimed at clinical prevention and treatment that reverses the course of disease does not exist currently. Active surveillance and effective laboratory diagnosis of CJD are, therefore, critical. In this report, the surveillance systems and laboratory tests used currently to diagnose CJD in different countries are reviewed. The current efforts to improve surveillance and diagnosis for CJD using molecular and biochemical findings are also described.

Progranulin peripheral levels as a screening tool for the identification of subjects with progranulin mutations in a Portuguese cohort

BACKGROUND

Progranulin (PGRN) mutations are associated with different clinical phenotypes, including frontotemporal lobar degeneration (FTLD), corticobasal syndrome (CBS) and Alzheimer's disease (AD). As all pathogenic PGRN mutations identified so far cause disease through haploinsufficiency, determination of PGRN levels has been proposed as a reliable method to identify mutation carriers.

OBJECTIVE

To evaluate the accuracy of peripheral PGRN levels in the identification of the PGRN mutation carriers detected thus far in our Portuguese cohort.

METHODS

Serum PGRN levels were measured in 244 subjects (124 patients in the spectrum of FTLD, 2 asymptomatic descendants of a FTLD patient, 56 AD patients and 64 controls) by a novel commercial ELISA kit.

RESULTS

Low PGRN levels were detected in 7 individuals (5 behavioral variant frontotemporal dementia, 1 CBS, and 1 still clinically unaffected) that constituted the group of the null PGRN mutation carriers previously identified in our molecular diagnostic laboratory. The pathogenic mutations found consisted of 4 insertion-deletions, causing frameshifts resulting in premature stop codons, 3 of which were novel. In addition, a normal PGRN level was found in a patient harboring a novel missense variant. For this novel ELISA kit, we established a PGRN cut-off level that identified with 100% accuracy the pathogenic mutation carriers.

CONCLUSION

This study supports the use of a novel assay for the determination of PGRN levels as a screening procedure to identify patients harboring null PGRN mutations. This approach would significantly decrease the required PGRN mutation analysis workload and should be extended to other clinical phenotypes than behavioral variant frontotemporal dementia and to apparently sporadic cases.

Chinese specific characteristics of sporadic Creutzfeldt-Jakob disease: a retrospective analysis of 57 cases

OBJECTIVE

Sporadic Creutzfeldt-Jakob disease (sCJD) is a fatal and transmissible neurodegenerative disorder. However, no studies have reported Chinese specific characteristics of sCJD. We aimed to identify differences in sCJD between Chinese patients and patients from other countries.

METHODS

The data from 57 Chinese sCJD patients were retrospectively analyzed, including demographic data, clinical manifestations, laboratory examinations, electroencephalograms (EEGs), diffusion-weighted imaging (DWI) scans, positron emission tomography (PET) scans, and pathological results.

RESULT

The disease was pathologically confirmed in 11 patients. 39 cases were diagnosed as probable sCJD, and 7 were possible. Of the total cases, 33 were male, and 24 were female. The onset age ranged from 36 to 75 years (mean: 55.5, median: 57). Disease onset before the age of 60 occurred in 57.9% of patients. The disease duration from onset to death ranged 5-22 months (mean: 11.6, median: 11), and 51.9% of patients died 7 to 12 months after disease onset. The majority of patients presented with sub-acute onset with progressive dementia. 3 of the 9 patients who took 14-3-3 protein analysis had positive results (33.3%). The sensitivity of EEG was 79.6% (43/54). For DWI and PET examinations, the sensitivities were 94% (47/50) and 94.1% (16/17), respectively. In seven patients who did not show typical hyper-intensities on the first DWI examination, abnormalities of hypo-metabolism in the cerebral cortex were clearly detected by PET. In 13 out of the 17 patients, PET detected extra abnormal regions in addition to the hyper-intense areas observed in DWI.

CONCLUSION

This is the first study to indicate that Chinese sCJD patients have a much earlier onset age and a longer disease duration than other populations, which is most likely related to racial differences. The longer disease duration may also be a probable characteristic of Asian populations. PET had high sensitivity for the diagnosis of sCJD.

Diagnostic accuracy of cerebrospinal fluid protein markers for sporadic Creutzfeldt-Jakob disease in Canada: a 6-year prospective study

BACKGROUND

To better characterize the value of cerebrospinal fluid (CSF) proteins as diagnostic markers in a clinical population of subacute encephalopathy patients with relatively low prevalence of sporadic Creutzfeldt-Jakob disease (sCJD), we studied the diagnostic accuracies of several such markers (14-3-3, tau and S100B) in 1000 prospectively and sequentially recruited Canadian patients with clinically suspected sCJD.

METHODS

The study included 127 patients with autopsy-confirmed sCJD (prevalence = 12.7%) and 873 with probable non-CJD diagnoses. Standard statistical measures of diagnostic accuracy were employed, including sensitivity (Se), specificity (Sp), predictive values (PVs), likelihood ratios (LRs), and Receiver Operating Characteristic (ROC) analysis.

RESULTS

At optimal cutoff thresholds (empirically selected for 14-3-3, assayed by immunoblot; 976 pg/mL for tau and 2.5 ng/mL for S100B, both assayed by ELISA), Se and Sp respectively were 0.88 (95% CI, 0.81-0.93) and 0.72 (0.69-0.75) for 14-3-3; 0.91 (0.84-0.95) and 0.88 (0.85-0.90) for tau; and 0.87 (0.80-0.92) and 0.87 (0.84-0.89) for S100B. The observed differences in Sp between 14-3-3 and either of the other 2 markers were statistically significant. Positive LRs were 3.1 (2.8-3.6) for 14-3-3; 7.4 (6.9-7.8) for tau; and 6.6 (6.1-7.1) for S100B. Negative LRs were 0.16 (0.10-0.26) for 14-3-3; 0.10 (0.06-0.20) for tau; and 0.15 (0.09-0.20) for S100B. Estimates of areas under ROC curves were 0.947 (0.931-0.961) for tau and 0.908 (0.888-0.926) for S100B. Use of interval LRs (iLRs) significantly enhanced accuracy for patient subsets [e.g., 41/120 (34.2%) of tested sCJD patients displayed tau levels > 10,000 pg/mL, with an iLR of 56.4 (22.8-140.0)], as did combining tau and S100B [e.g., for tau > 976 pg/mL and S100B > 2.5 ng/mL, positive LR = 18.0 (12.9-25.0) and negative LR = 0.02 (0.01-0.09)].

CONCLUSIONS

CSF 14-3-3, tau and S100B proteins are useful diagnostic markers of sCJD even in a low-prevalence clinical population. CSF tau showed better overall diagnostic accuracy than 14-3-3 or S100B. Reporting of quantitative assay results and combining tau with S100B could enhance case definitions used in diagnosis and surveillance of sCJD.

Cerebrospinal fluid markers in sporadic Creutzfeldt-Jakob disease

Sporadic Creutzfeldt-Jakob disease (sCJD) is the commonest form of human prion diseases, accounting for about 85% of all cases. Current criteria for intra vitam diagnosis include a distinct phenotype, periodic sharp and slow-wave complexes at electroencephalography (EEG), and a positive 14-3-3-protein assay in the cerebrospinal fluid (CSF). In sCJD, the disease phenotype may vary, depending upon the genotype at codon 129 of the prion protein gene (PRNP), a site of a common methionine/valine polymorphism, and two distinct conformers of the pathological prion protein. Based on the combination of these molecular determinants, six different sCJD subtypes are recognized, each with distinctive clinical and pathologic phenotypes. We analyzed CSF samples from 127 subjects with definite sCJD to assess the diagnostic value of 14-3-3 protein, total tau protein, phosphorylated₁₈₁ tau, and amyloid beta (Aβ) peptide 1-42, either alone or in combination. While the 14-3-3 assay and tau protein levels were the most sensitive indicators of sCJD, the highest sensitivity, specificity and positive predictive value were obtained when all the above markers were combined. The latter approach also allowed a reliable differential diagnosis with other neurodegenerative dementias.

Molecular diagnosis of human prion disease

INTRODUCTION

Human prion diseases (PrDs) are transmissible fatal nervous system disorders with public health implications. They are characterized by the presence of a disease-associated form of the physiological cellular prion protein. Development of diagnostic procedures is important to avoid transmission, including through blood products. Methods used for the detection of disease-associated PrP have implications for other neurodegenerative diseases.

AREAS COVERED

In this review, the authors discuss recent progress in the understanding of the molecular background of phenotypic variability of human PrDs, and the current concepts of molecular diagnosis. Also, the authors provide a critical summary of the diagnostic methods with regard to the molecular subtypes.

EXPERT OPINION

In spite of a lack of specific tests to detect disease-associated PrP in body fluids, the constellation of clinical symptoms, detection of protein 14-3-3 in cerebrospinal fluid, electroencephalogram, cranial MRI and prion protein gene examinations, together have increased the specificity and sensitivity of in vivo diagnostics. As new forms of PrDs are reported, continuous evaluation of their incidence and the search for their etiology is crucial. Recent studies, suggesting prion-like properties of certain proteinopathies associated with Parkinson's or Alzheimer's disease, have again brought PrDs to the center of interest as a model of diseases with disordered protein processing.

Decreased CSF transferrin in sCJD: a potential pre-mortem diagnostic test for prion disorders

Sporadic Creutzfeldt-Jakob-disease (sCJD) is a fatal neurodegenerative condition that escapes detection until autopsy. Recently, brain iron dyshomeostasis accompanied by increased transferrin (Tf) was reported in sCJD cases. The consequence of this abnormality on cerebrospinal-fluid (CSF) levels of Tf is uncertain. We evaluated the accuracy of CSF Tf, a ‘new’ biomarker, as a pre-mortem diagnostic test for sCJD when used alone or in combination with the ‘current’ biomarker total-tau (T-tau). Levels of total-Tf (T-Tf), isoforms of Tf (Tf-1 and Tf-β2), and iron saturation of Tf were quantified in CSF collected 0.3–36 months before death (duration) from 99 autopsy confirmed sCJD (CJD+) and 75 confirmed cases of dementia of non-CJD origin (CJD-). Diagnostic accuracy was estimated by non-parametric tests, logistic regression, and receiver operating characteristic (ROC) analysis. Area under the ROC curve (AUC), sensitivity, specificity, positive and negative predictive values (PV), and likelihood ratios (LR) of each biomarker and biomarker combination were calculated. We report that relative to CJD-, CJD+ cases had lower median CSF T-Tf (125,7093 vs. 217,7893) and higher T-tau (11530 vs. 1266) values. AUC was 0.90 (95% confidence interval (CI), 0.85–0.94) for T-Tf, and 0.93 (95% CI, 0.89–0.97) for T-Tf combined with T-tau. With cut-offs defined to achieve a sensitivity of ∼85%, T-Tf identified CJD+ cases with a specificity of 71.6% (95% CI, 59.1–81.7), positive LR of 3.0 (95% CI, 2.1–4.5), negative LR of 0.2 (95% CI, 0.1–0.3), and accuracy of 80.1%. The effect of patient age and duration was insignificant. T-Tf combined with T-tau identified CJD+ with improved specificity of 87.5% (95%CI, 76.3–94.1), positive LR of 6.8 (95% CI, 3.5–13.1), negative LR of 0.2 (95% CI, 0.1–0.3), positive-PV of 91.0%, negative-PV of 80.0%, and accuracy of 86.2%. Thus, CSF T-Tf, a new biomarker, when combined with the current biomarker T-tau, is a reliable pre-mortem diagnostic test for sCJD.

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%.