A protein panel in cerebrospinal fluid for diagnostic and predictive assessment of Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative disease with heterogenous pathophysiological changes that develop years before the onset of clinical symptoms. These preclinical changes have generated considerable interest in identifying markers for the pathophysiological mechanisms linked to AD and AD-related disorders (ADRD). On the basis of our prior work integrating cerebrospinal fluid (CSF) and brain proteome networks, we developed a reliable and high-throughput mass spectrometry-selected reaction monitoring assay that targets 48 key proteins altered in CSF. To test the diagnostic utility of these proteins and compare them with existing AD biomarkers, CSF collected at baseline visits was assayed from 706 participants recruited from the Alzheimer's Disease Neuroimaging Initiative. We found that the targeted CSF panel of 48 proteins (CSF 48 panel) performed at least as well as existing AD CSF biomarkers (Aβ42, tTau, and pTau181) for predicting clinical diagnosis, FDG PET, hippocampal volume, and measures of cognitive and dementia severity. In addition, for each of those outcomes, the CSF 48 panel plus the existing AD CSF biomarkers significantly improved diagnostic performance. Furthermore, the CSF 48 panel plus existing AD CSF biomarkers significantly improved predictions for changes in FDG PET, hippocampal volume, and measures of cognitive decline and dementia severity compared with either measure alone. A potential reason for these improvements is that the CSF 48 panel reflects a range of altered biology observed in AD/ADRD. In conclusion, we show that the CSF 48 panel complements existing AD CSF biomarkers to improve diagnosis and predict future cognitive decline and dementia severity.

Population-Based Evaluation of Total Protein in Cerebrospinal Fluid

OBJECTIVES

To present a normal range of cerebrospinal fluid (CSF) protein levels in a community-based population and to evaluate factors that contribute to CSF protein level variability.

PATIENTS AND METHODS

Samples of CSF protein were obtained from participants aged 32 to 95 years who underwent lumbar puncture (LP) between November 1, 2007, and October 1, 2017, as part of the Mayo Clinic Study of Aging, a longitudinal, population-based study of residents of Olmsted County, Minnesota.

RESULTS

A total of 633 participants (58.1% male; 99.1% White; mean ± SD age, 70.9±11.6 years) underwent LP with recorded CSF protein level. Mean ± SD CSF protein level was 52.2±18.4 mg/dL (to convert to mg/L, multiply by 10), with a 95% reference interval of 24.0 to 93.4 mg/dL (range, 14.0-148.0 mg/dL). Spinal stenosis and arterial hypertension were associated with higher CSF protein levels on univariable analysis (P<.001). Increasing age, male sex, and diabetes were all independently associated with higher CSF protein levels on multivariable analysis (P<.001). In the 66 participants with repeated LPs within 2.5 years, the coefficient of repeatability was 26.1 mg/dL. Eleven participants (16.7%) had a CSF protein level difference of 20 mg/dL or more between serial LPs, and 4 (6.1%) had a difference of 25 mg/dL or more. There was a trend toward greater CSF protein level variability in patients with spinal stenosis (P=.054).

CONCLUSION

This large population-based study showed that CSF protein level can vary significantly among individuals. Elevated CSF protein level was independently associated with older age, male sex, and diabetes and is higher than listed in many laboratories. These findings emphasize the necessity of evidence-based reevaluation and standardization of CSF protein metrics.

Clinical and Radiological Characteristics of Children and Adults With First-Attack Myelin Oligodendrocyte Glycoprotein Antibody Disease and Analysis of Risk Factors for Predicting the Severity at Disease Onset in Central China

Objective

To analyze and compare different clinical, laboratory, and magnetic resonance imaging characteristics between pediatric and adult patients with first-attack myelin oligodendrocyte glycoprotein antibody disease (MOGAD) and to explore predictive factors for severity at disease onset.

Methods

Patients diagnosed with MOGAD at the First Affiliated Hospital of Zhengzhou University from January 2013 to August 2021 were enrolled in this retrospective study. Age at disease onset, sex, comorbidities, laboratory tests, magnetic resonance imaging (MRI) characteristics, and Expanded Disability Status Scale (EDSS) scores were collected and analyzed. The association between risk factors and initial EDSS scores at disease onset was analyzed using logistic regression models and Spearman correlation analyses. A receiver-operating characteristic (ROC) curve analysis was used to evaluate the predictive ability of the uric acid and homocysteine (Hcy) levels for the severity of neurological dysfunction at the onset of MOGAD.

Results

Sixty-seven patients (female, n=34; male, n=33) with first-attack MOGAD were included in this study. The mean age at onset was 26.43 ± 18.22 years (range: 3–79 years). Among patients &lt;18 years of age, the most common presenting symptoms were loss of vision (36.0%), and nausea and vomiting (24.0%), and the most common disease spectrum was acute disseminated encephalomyelitis (ADEM) (40.0%). Among patients aged ≥18 years, the most common presenting symptoms were loss of vision (35.7%), paresthesia (33.3%), and paralysis (26.2%), and the most common disease spectrum was optic neuritis (35.7%). The most common lesions were cortical gray matter/paracortical white matter lesions in both pediatric and adult patients. Uric acid [odds ratio (OR)=1.014; 95% confidence interval (CI)=1.006–1.022; P=0.000] and serum Hcy (OR=1.125; 95% CI=1.017–1.246; P=0.023) levels were significantly associated with the severity of neurological dysfunction at disease onset. Uric acid levels (r=0.2583; P=0.035) and Hcy levels (r=0.3971; P=0.0009) were positively correlated with initial EDSS scores. The areas under the ROC curve were 0.7775 (95% CI= 0.6617‒0.8933; P&lt;0.001) and 0.6767 (95% CI=0.5433‒0.8102, P=0.014) for uric acid and Hcy levels, respectively.

Conclusion

The clinical phenotype of MOGAD varies in patients of different ages. The most common disease spectrum was ADEM in patients aged&lt;18 years, while optic neuritis was commonly found in patients aged ≥18 years. The uric acid and Hcy levels are risk factors for the severity of neurological dysfunction at disease onset in patients with first-attack MOGAD.

Longitudinal Bottom-Up Proteomics of Serum, Serum Extracellular Vesicles, and Cerebrospinal Fluid Reveals Candidate Biomarkers for Early Detection of Glioblastoma in a Murine Model

Glioblastoma Multiforme (GBM) is a brain tumor with a poor prognosis and low survival rates. GBM is diagnosed at an advanced stage, so little information is available on the early stage of the disease and few improvements have been made for earlier diagnosis. Longitudinal murine models are a promising platform for biomarker discovery as they allow access to the early stages of the disease. Nevertheless, their use in proteomics has been limited owing to the low sample amount that can be collected at each longitudinal time point. Here we used optimized microproteomics workflows to investigate longitudinal changes in the protein profile of serum, serum small extracellular vesicles (sEVs), and cerebrospinal fluid (CSF) in a GBM murine model. Baseline, pre-symptomatic, and symptomatic tumor stages were determined using non-invasive motor tests. Forty-four proteins displayed significant differences in signal intensities during GBM progression. Dysregulated proteins are involved in cell motility, cell growth, and angiogenesis. Most of the dysregulated proteins already exhibited a difference from baseline at the pre-symptomatic stage of the disease, suggesting that early effects of GBM might be detectable before symptom onset.

Sexual dimorphism in the cerebrospinal fluid total protein content

Objectives Cerebrospinal fluid (CSF) is a clear, colorless body fluid filling the central nervous system. The determination of the CSF total protein (TP) content represents an important screening test of various pathologies. We aimed to address the effect of sex and age on CSF-TP content and the use of the current upper reference limits (URLs). Methods CSF-TP content was analysed in a selected population of 1,252 patients (648 women and 604 men; age 18-89 years) who underwent lumbar puncture as a part of the diagnostic work-up. Samples presenting (i) more than 5 white blood cells (WBC)/µL, (ii) discolorations and (iii) reduced glucose were not included. Results The CSF-TP content median values were significantly higher in men than in women (46 vs. 37 mg/dL) even after adjusting for age and different hospital inpatients. CSF-TP content positively correlated with age both in men and in women with a constant difference between sexes of 8.5 mg/dL. Applying the most used URLs (mainly 45 and 50 mg/dL, but also 60 mg/dL), men received a laboratory report suggestive of altered CSF-TP content more frequently than women. The use of age- and sex-calibrated CSF-TP URLs reduced, but not eliminated, this sex-gap. Conclusions Using the current URLs, a condition of "elevated CSF-TP content" may be overestimated in men or, conversely, underestimated in women, regardless of the age and of the diagnosis. These results highlighted the need to apply CSF-TP URLs values ​​normalized for both sex and age.

Proteomic landscape of Alzheimer's Disease: novel insights into pathogenesis and biomarker discovery

Mass spectrometry-based proteomics empowers deep profiling of proteome and protein posttranslational modifications (PTMs) in Alzheimer's disease (AD). Here we review the advances and limitations in historic and recent AD proteomic research. Complementary to genetic mapping, proteomic studies not only validate canonical amyloid and tau pathways, but also uncover novel components in broad protein networks, such as RNA splicing, development, immunity, membrane transport, lipid metabolism, synaptic function, and mitochondrial activity. Meta-analysis of seven deep datasets reveals 2,698 differentially expressed (DE) proteins in the landscape of AD brain proteome (n = 12,017 proteins/genes), covering 35 reported AD genes and risk loci. The DE proteins contain cellular markers enriched in neurons, microglia, astrocytes, oligodendrocytes, and epithelial cells, supporting the involvement of diverse cell types in AD pathology. We discuss the hypothesized protective or detrimental roles of selected DE proteins, emphasizing top proteins in "amyloidome" (all biomolecules in amyloid plaques) and disease progression. Comprehensive PTM analysis represents another layer of molecular events in AD. In particular, tau PTMs are correlated with disease stages and indicate the heterogeneity of individual AD patients. Moreover, the unprecedented proteomic coverage of biofluids, such as cerebrospinal fluid and serum, procures novel putative AD biomarkers through meta-analysis. Thus, proteomics-driven systems biology presents a new frontier to link genotype, proteotype, and phenotype, accelerating the development of improved AD models and treatment strategies.

Higher CSF sTNFR1-related proteins associate with better prognosis in very early Alzheimer's disease

Neuroinflammation is associated with Alzheimer's disease, but the application of cerebrospinal fluid measures of inflammatory proteins may be limited by overlapping pathways and relationships between them. In this work, we measure 15 cerebrospinal proteins related to microglial and T-cell functions, and show them to reproducibly form functionally-related groups within and across diagnostic categories in 382 participants from the Alzheimer's Disease Neuro-imaging Initiative as well participants from two independent cohorts. We further show higher levels of proteins related to soluble tumor necrosis factor receptor 1 are associated with reduced risk of conversion to dementia in the multi-centered (p = 0.027) and independent (p = 0.038) cohorts of people with mild cognitive impairment due to predicted Alzheimer's disease, while higher soluble TREM2 levels associated with slower decline in the dementia stage of Alzheimer's disease. These inflammatory proteins thus provide prognostic information independent of established Alzheimer's markers.

Serum and cerebrospinal fluid host proteins indicate stroke in children with tuberculous meningitis

Introduction

Stroke is a common complication in children with tuberculous meningitis (TBM). Host proteins may give us insight into the mechanisms of stroke in TBM and serve as biomarkers for detection of stroke, however, they have not been widely explored. In this study, we compared the concentrations of cerebrospinal fluid (CSF) and serum proteins between children who had TBM-related stroke and children with TBM without stroke.

Methods

We collected CSF and serum from 47 children consecutively admitted to the Tygerberg Academic Hospital in Cape Town, South Africa between November 2016, and November 2017, on suspicion of having TBM. A multiplex platform was used to measure the concentrations of 69 host proteins in CSF and serum from all study participants.

Results

After classification of study participants, 23 (48.9%) out of the 47 study participants were diagnosed with TBM, of which 14 (60.9%) demonstrated radiological arterial ischemic infarction. The levels of lipocalin-2, sRAGE, IP-10/ CXCL10, sVCAM-1, MMP-1, and PDGF-AA in CSF samples and the levels of D-dimer, ADAMTS13, SAA, ferritin, MCP-1/ CCL2, GDF-15 and IL-13 in serum samples were statistically different between children who had TBM-related stroke and children with TBM without stroke. After correcting for multiple testing, only the levels of sVCAM-1, MMP-1, sRAGE, and IP-10/ CXCL10 in CSF were statistically different between the two groups. CSF and serum protein biosignatures indicated stroke in children diagnosed with TBM with up to 100% sensitivity and 88.9% specificity.

Conclusion

Serum and CSF proteins may serve as biomarkers for identifying individuals with stroke amongst children diagnosed with TBM at admission and may guide us to understand the biology of stroke in TBM. This was a pilot study, and thus further investigations in larger studies are needed.

Cerebrospinal fluid proteome shows disrupted neuronal development in multiple sclerosis

Despite intensive research, the aetiology of multiple sclerosis (MS) remains unknown. Cerebrospinal fluid proteomics has the potential to reveal mechanisms of MS pathogenesis, but analyses must account for disease heterogeneity. We previously reported explorative multivariate analysis by hierarchical clustering of proteomics data of MS patients and controls, which resulted in two groups of individuals. Grouping reflected increased levels of intrathecal inflammatory response proteins and decreased levels of proteins involved in neural development in one group relative to the other group. MS patients and controls were present in both groups. Here we reanalysed these data and we also reanalysed data from an independent cohort of patients diagnosed with clinically isolated syndrome (CIS), who have symptoms of MS without evidence of dissemination in space and/or time. Some, but not all, CIS patients had intrathecal inflammation. The analyses reported here identified a common protein signature of MS/CIS that was not linked to elevated intrathecal inflammation. The signature included low levels of complement proteins, semaphorin-7A, reelin, neural cell adhesion molecules, inter-alpha-trypsin inhibitor heavy chain H2, transforming growth factor beta 1, follistatin-related protein 1, malate dehydrogenase 1 cytoplasmic, plasma retinol-binding protein, biotinidase, and transferrin, all known to play roles in neural development. Low levels of these proteins suggest that MS/CIS patients suffer from abnormally low oxidative capacity that results in disrupted neural development from an early stage of the disease.

Inflammatory Leptomeningeal Cytokines Mediate COVID-19 Neurologic Symptoms in Cancer Patients

SARS-CoV-2 infection induces a wide spectrum of neurologic dysfunction that emerges weeks after the acute respiratory infection. To better understand this pathology, we prospectively analyzed of a cohort of cancer patients with neurologic manifestations of COVID-19, including a targeted proteomics analysis of the cerebrospinal fluid. We find that cancer patients with neurologic sequelae of COVID-19 harbor leptomeningeal inflammatory cytokines in the absence of viral neuroinvasion. The majority of these inflammatory mediators are driven by type II interferon and are known to induce neuronal injury in other disease states. In these patients, levels of matrix metalloproteinase-10 within the spinal fluid correlate with the degree of neurologic dysfunction. Furthermore, this neuroinflammatory process persists weeks after convalescence from acute respiratory infection. These prolonged neurologic sequelae following systemic cytokine release syndrome lead to long-term neurocognitive dysfunction. Our findings suggest a role for anti-inflammatory treatment(s) in the management of neurologic complications of COVID-19 infection.

Early onset neonatal bacterial meningitis in term infants: the clinical features, perinatal conditions, and in-hospital outcomes: A single center retrospective analysis

To compare clinical features and outcomes between early and late onset of neonatal bacterial meningitis (NBM).Patients were allocated in 2 groups: early onset neonatal bacterial meningitis (ENBM) and late onset neonatal bacterial meningitis (LNBM). Data analysis includes asphyxia at birth, premature rupture of membranes (PROM), amnionitis, amniotic fluid contamination, maternal age, clinical manifestations of the patients, laboratory findings, radiological results, complications related to meningitis, duration of hospitalization and therapeutic effect.There was no difference in gender, birth weight, gestational age, and incidence of asphyxia between 2 groups. The incidence of PROM, chorioamnionitis and amniotic fluid contamination, proportion of small-for-gestational-age infants, convulsions, intracranial hemorrhage, hyperbilirubinemia, and the protein level of cerebrospinal fluid in ENBM group were higher than that in LNBM group (P < .05); the proportion of fever, elevated C-reaction protein and the abnormal of platelet counts in LNBM group was higher than that in ENBM group (P < .05). There was no difference in the incidence of complications and hospitalization time between 2 groups. The rate of effective treatment in LNBM group was significantly higher than that in ENBM group (P < .05).Patients with conditions of amniotic fluid contamination, chorioamnionitis, small-for-gestational-age and PROM might be more prone to develop ENBM and ENBM had worse outcomes than LNBM.

Clinicopathological characteristics of primary central nervous system lymphoma with low 18F-fludeoxyglucose uptake on brain positron emission tomography

Primary central nervous system lymphoma (PCNSL) typically shows a strong uptake of F-fludeoxyglucose (FDG) imaged by positron emission tomography (PET). Uncommonly, PCNSL demonstrates a low uptake on FDG PET. We investigated the clinicopathological characteristics of the unusual cases of PCNSL with low FDG uptake.We retrospectively enrolled 104 consecutive patients with newly diagnosed PCNSL who underwent baseline brain FDG PET. The degree of FDG uptake of PCNSL was visually scored by 4 grades (0, ≤contralateral white matter; 1, >contralateral white matter and <contralateral gray matter; 2, = contralateral gray matter; 3, >contralateral gray matter). Grades 0-2 were considered as PCNSL with low uptake. We investigated association of low uptake of PCNSL with the following clinicopathological factors: age, sex, steroid treatment, lactate dehydrogenase level, cerebrospinal fluid protein level, condition of PET scanning, immunohistochemical markers (cluster of differentiation 10 [CD10], B-cell lymphoma 6 [BCL-6], B-cell lymphoma 2 [BCL-2], multiple myeloma oncogene 1 [MUM1], Epstein-Barr virus [EBV] protein, and Ki67), location of lesions, tumor size, multiplicity of lesions, involvement of deep brain structures, and cystic or necrotic appearance of lesions.Of the 104 patients with PCNSL, 14 patients (13.5%) showed PCNSL with low FDG uptake on PET. Among various clinicopathological factors, MUM1 negativity was the only factor associated with low FDG uptake PCNSL by univariate (P = .002) and multivariate analysis (P = .007).This study suggests that the different clinicopathological characteristics between patients with high uptake and low uptake of PCNSL on FDG PET is closely associated with lack of MUM1, a protein known to be a crucial regulator of B-cell development and tumorigenesis.

Age-specific reference values for cerebrospinal fluid protein concentrations in children in southern China

Cerebrospinal fluid (CSF) protein values decline over the first few months of life as the infant's blood-CSF barrier matures. However, published studies have not reported CSF protein reference values of Chinese infants and differ in the reported rate, timing, and magnitude of this decline. The objective of this study was to determine reference intervals for CSF protein using available data of children in southern China. This retrospective study included infants who had a lumbar puncture (LP) performed in the Department of Pediatrics of Southern Medical University Affiliated Maternal and Child Health Hospital of Foshan of an urban tertiary care children's hospital between January 1, 2008 and May 31, 2018. Infants with conditions suspected or known to cause elevated CSF protein concentrations were excluded. Of 3712 infants undergoing LP, 1043 (28.1%) met inclusion criteria. Results showed that there is an age-related decline in CSF protein concentration. The median CSF protein value was 62 mg/dL [interquartile range (IQR): 47-81 mg/dL] in infants aged 0 to 56 days (group 1). The 95th percentile values were 116 mg/dL for infants 0 to 28 days and 80 mg/dL for infants 29 to 56 days. The 95th percentile values by age category were as follows: ages 0 to 14 days, 117 mg/dL; ages 15 to 28 days, 107 mg/dL; ages 29 to 42 days, 96 mg/dL; and ages 43 to 56 days, 74 mg/dL. The median CSF protein value was 21 mg/dL (IQR: 16-31 mg/dL) in infants aged 2 months to <3 years (group 2). The 95th percentile values were 57 mg/dL for infants 2 to <6 months and 34 mg/dL for infants 6 to ≤24 months. The 95th percentile values by age category were as follows: ages 2 to <3 months, 66 mg/dL; ages 3 to <4 months, 52 mg/dL; ages 4 to <5 months, 53 mg/dL; and ages 5 to <6 months, 42 mg/dL. We quantify the age-related decline in CSF protein concentrations among infants 2 years of age and younger and provide age-specific reference values. The values reported here can be used to interpret the results of LP in infants ≤2 years of age.

Causes of albuminocytological dissociation and the impact of age-adjusted cerebrospinal fluid protein reference intervals: a retrospective chart review of 2627 samples collected at tertiary care centre

OBJECTIVE

We set out to test the discriminative power of an age-adjusted upper reference limit for cerebrospinal fluid total protein (CSF-TP) in identifying clinically relevant causes of albuminocytological dissociation (ACD).

METHODS

We reviewed the charts of 2627 patients who underwent a lumbar puncture at a tertiary care centre over a 20-year period. Samples with CSF-TP above 45 mg/dL (0.45 g/L) were included. Samples with white cell count >5×10⁹/L, red cell count >50×10⁹/L and glucose <2.5 mmol/L (45 mg/dL) were excluded as were samples with incomplete data and those taken from paediatric patients (ie, age <18 years old). Patients with CSF-TP elevated above 45 mg/dL were considered to have 'pseudo' ACD unless their CSF-TP was in excess of age-adjusted norms in which case they were considered to have 'true' ACD. Adjustment for sex was not applied to the age-adjusted norms although the importance of gender has been previously described.

RESULTS

The presence of ACD was associated with a broad range of neurological diagnoses. Among all 2627 patients with ACD, a clinical diagnosis explaining CSF-TP elevation was identified in 57% of cases. 'True' ACD was associated with a suitable diagnosis in 75% of cases, whereas patients with 'pseudo' ACD showed an appropriate diagnosis in only 51% of cases. Use of an age-adjusted upper reference limit favoured the detection of polyneuropathy patients (13.5% proportionate increase) and excluded a larger number of patients with isolated headache (10.7% proportionate decrease; p<0.0001).

CONCLUSIONS

Elevated CSF-TP is a common finding, with a range of underlying causes. Use of an age-adjusted upper reference limit for the CSF-TP value improves diagnostic specificity and helps to avoid overdiagnosis of ACD.

Quantitative Evaluation of Different Protein Fractions of Cerebrospinal Fluid Using 18O Labeling

Molecular analysis of cerebrospinal fluid (CSF) provides comprehensive information on physiological and pathological processes related to the brain. In particular, proteomic studies give insights into the pathogenesis of many brain diseases which still pose diagnostic and therapeutic challenges. The identification of reliable biomarkers is an important step to meet these challenges. Mass spectrometry is an essential proteomic tool, not only for highly sensitive identification of proteins and posttranslational modifications, but also for their reliable quantification. Here, ¹⁸O labeling of tryptic peptides was employed to qualitative and quantitative analyses of protein fractions obtained by depletion of highly abundant proteins from cerebrospinal fluid. It was found that the execution of the investigated depletion protocols may cause the loss of potential protein biomarkers of neurological diseases.

SWATH Mass Spectrometry Applied to Cerebrospinal Fluid Differential Proteomics: Establishment of a Sample-Specific Method

Mass spectrometry (MS) has become the gold standard method for proteomics by allowing the simultaneous identification and/or quantification of thousands of proteins of a given sample. Over time, mass spectrometry has evolved into newer quantitative approaches with increased sensitivity and accuracy, such as the sequential windows acquisition of all theoretical fragment-ion spectra (SWATH)-MS approach. Moreover, in the past few years, some improvements were made in the SWATH-acquisition algorithm, allowing the design of sample-customized acquisition methods by adjusting the Q1 windows' width in order to reduce it in the most populated m/z regions. This customization results in an increase in the specificity and a reduction in the interferences, ultimately leading to an improvement in the amount of quantitative data extracted to eventually increase the proteome coverage. These improvements are especially relevant for clinical neuroproteomics, which is mainly based on the analysis of circulatory biofluids, in particular the cerebrospinal fluid (CSF) due to its close connection with the brain.In the present chapter, a detailed description of the methodologies necessary to perform a whole-proteome relative quantification of CSF samples by SWATH-MS is presented, starting with the isolation of the protein fraction, its preparation for MS analysis, with all the necessary information for the design of a SWATH-MS method specific for each sample batch, and finally providing different methodologies for the analysis of the quantitative data obtained.

Determination of Cerebrospinal Fluid Proteome Variations by Isobaric Labeling Coupled with Strong Cation-Exchange Chromatography and Tandem Mass Spectrometry

Cerebrospinal fluid (CSF) is in direct contact with the brain and represents a valuable source of mediators that reflect metabolic processes occurring in the central nervous system (CNS). In this sense, mass spectrometry (MS) methods have proven to be sensitive in quantifying the proteomic profiles of CSF, therefore being able to detect biomarker candidates for neurological disorders. In particular, a key development has been the use of multiplexing technologies to easily identify and quantify complex protein mixtures. This chapter describes a workflow suitable for the analysis of CSF proteome using isobaric labeling coupled to strong cation-exchange chromatography fractionation for its potential use as a biomarker discovery platform. In this case, the isobaric tags for relative and absolute quantitation (iTRAQ) label all proteins in a sample via free amines at the N-terminus and on the side chain of lysine residues. Then, the labeled samples are pooled and chromatographically fractionated. These fractions with the pooled samples are afterward analyzed by tandem mass spectrometry (MS/MS), and proteins are quantified by the relative intensities of the reporter ions in the MS/MS spectra, simultaneously obtaining the amino acid sequence. This method complements the neuroproteomic toolbox to identify new protein biomarkers not only for the early clinical diagnosis and disease staging of CNS-related disorders but also to elucidate the molecular mechanisms related to the pathophysiology of these symptoms.

Application of 2D-DIGE and iTRAQ Workflows to Analyze CSF in Gliomas

Proteomics is an indispensable tool for disease biomarker discovery. It is widely used for the analysis of biological fluids such as cerebrospinal fluid (CSF), blood, and saliva, which further aids in our understanding of disease incidence and progression. CSF is often the biospecimen of choice in case of intracranial tumors, as rapid changes in the tumor microenvironment can be easily assessed due to its close proximity to the brain. On the contrary studies comprising of serum or plasma samples do not truly reflect the underlying molecular alterations due to the presence of protective blood-brain barrier. We have described in here the detailed workflows for two advanced proteomics techniques, namely, 2D-DIGE (two-dimensional difference in-gel electrophoresis) and iTRAQ (isobaric tag for relative and absolute quantitation), for CSF analysis. Both of these techniques are very sensitive and widely used for quantitative proteomics analysis.

Characteristics, outcome and treatments with cranial pachymeningitis: A multicenter French retrospective study of 60 patients

The aim of this study was to determine the characteristics, treatment, and outcome according to each etiology of pachymeningitis.We conducted a retrospective multicenter French nationwide study between 2000 and 2016 to describe the characteristics, outcome, and treatment of pachymeningitis.We included 60 patients (median age 55.5 years; interquartile range [IQR] 30-80, female/male ratio 0.43). Neurologic signs were present in 59 patients (98%) and consisted of headache in 43 (72%), cranial nerve palsy in 33 (55%), confusion in 10 (17%), seizures in 7 (12%), and focal neurologic signs in 9 (15%). Fever and weight loss were present in 8 (13%) and 13 cases (22%), respectively. Cerebral venous thrombosis was present in 8 cases (13%). Analysis of cerebrospinal fluid showed moderate hyperproteinorachia (median 0.68 g/L; IQR 0.46-3.2) with or without pleiocytosis. Diagnosis included idiopathic pachymeningitis (n = 18; 30%); granulomatosis with polyangiitis (n = 13; 17%); Erdheim-Chester disease (n = 10; 17%); IgG4-related disease and tuberculosis (n = 3; 5% each); Rosai-Dofman disease, microscopic polyangiitis, and sarcoidosis (n = 2, 3% each); cryptococcal meningitis, Lyme disease, ear-nose-throat infection, postlumbar puncture, low spinal-fluid pressure syndrome, and lymphoma (n = 1 each). We found no difference in demographics and neurologic presentation among idiopathic pachymeningitis, Erdheim-Chester disease, and granulomatosis with polyangiitis. In contrast, frequencies were lower with idiopathic pachymeningitis than Erdheim-Chester disease for general signs (6% and 40%, respectively, P = .041) and complete neurologic response (0% vs 39%, P = .045).The detection of extraneurologic signs and routine screening are needed to classify the pachymeningitis origin. Prospective studies are warranted to determine the best treatment in each case.

Comprehensive analysis of patients with neuromyelitis optica spectrum disorder (NMOSD) combined with chronic hepatitis B (CHB) infection and seropositive for anti-aquaporin-4 antibody

Previous research indicated the association between hepatitis B virus (HBV) infection/vaccination and the onset of demyelinating diseases. However, most of these studies were single case reports, and comprehensive data are still scarce. Here we present a comprehensive analysis of 10 patients with neuromyelitis optica spectrum disorder (NMOSD) combined with chronic hepatitis B (CHB) infection and seropositive for anti-aquaporin-4 antibody (AQP4-Ab). Demographic, clinical, laboratory, neuroimaging, outcome, and follow-up data of the 10 patients were retrospectively analyzed. The median age at the onset of NMOSD was 35 years (range 25-43). Nine patients were female (90%). All patients were positive for HBsAg and had been diagnosed with CHB earlier than with NMOSD. One patient had an autoimmune disease. All patients had normal thyroid function. Paresthesia and visual impairment were the most common clinical symptoms. The cerebrospinal fluid (CSF) parameters (protein and glucose) were normal in 10 cases, whereas slightly higher CSF white blood cell count was detected in 3 patients. The brain and spinal cord magnetic resonance imaging findings were abnormal in 8 patients. All patients were treated with hormone and immunosuppressive therapy, and anti-HBV agents. Patients with detectable serum HBV DNA were more prone to liver damage after receiving high doses of corticosteroids. In 8 patients, the symptoms improved before they were discharged. Two patients with optic neuritis (ON) maintained the symptoms. A month later, 1/8 patient had recurrence of symptoms, and one ON patient progressed to NMO. Overall, the characteristics of NMOSD patients with CHB and seropositive for AQP4-Ab are usually nonspecific. Abnormal liver function test results in NMOSD patients should be a warning of possible CHB infection, and the treatment should be modified accordingly.

MR Imaging Features of the Cerebellum in Adult-Onset Neuronal Intranuclear Inclusion Disease: 8 Cases

Neuronal intranuclear inclusion disease is a neurodegenerative disorder pathologically characterized by eosinophilic hyaline intranuclear inclusions. A high-intensity signal along the corticomedullary junction on DWI has been described as a specific MR imaging finding of the cerebrum in neuronal intranuclear inclusion disease. However, MR imaging findings of the cerebellum in neuronal intranuclear inclusion disease have not been fully evaluated. Here, we review MR imaging findings of the cerebellum in a series of 8 patients with pathologically confirmed neuronal intranuclear inclusion disease. The MR imaging results showed cerebellar atrophy (8/8 patients) and high-intensity signal on FLAIR images in the medial part of the cerebellar hemisphere right beside the vermis (the "paravermal area") (6/8) and in the middle cerebellar peduncle (4/8). The paravermal abnormal signals had a characteristic distribution, and they could be an indicator of the diagnosis of neuronal intranuclear inclusion disease even when using the results of past MR imaging examinations in which DWI findings were not examined.

Elucidation of the complex metabolic profile of cerebrospinal fluid using an untargeted biochemical profiling assay

We sought to determine the molecular composition of human cerebrospinal fluid (CSF) and identify the biochemical pathways represented in CSF to understand the potential for untargeted screening of inborn errors of metabolism (IEMs). Biochemical profiles for each sample were obtained using an integrated metabolomics workflow comprised of four chromatographic techniques followed by mass spectrometry. Secondarily, we wanted to compare the biochemical profile of CSF with those of plasma and urine within the integrated mass spectrometric-based metabolomic workflow. Three sample types, CSF (N=30), urine (N=40) and EDTA plasma (N=31), were analyzed from retrospectively collected pediatric cohorts of equivalent age and gender characteristics. We identified 435 biochemicals in CSF representing numerous biological and chemical/structural families. Sixty-three percent (273 of 435) of the biochemicals detected in CSF also were detected in urine and plasma, another 32% (140 of 435) were detected in either plasma or urine, and 5% (22 of 435) were detected only in CSF. Analyses of several metabolites showed agreement between clinically useful assays and the metabolomics approach. An additional set of CSF and plasma samples collected from the same patient revealed correlation between several biochemicals detected in paired samples. Finally, analysis of CSF from a pediatric case with dihydropteridine reductase (DHPR) deficiency demonstrated the utility of untargeted global metabolic phenotyping as a broad assessment to screen samples from patients with undifferentiated phenotypes. The results indicate a single CSF sample processed with an integrated metabolomics workflow can be used to identify a large breadth of biochemicals that could be useful for identifying disrupted metabolic patterns associated with IEMs.

[Subacute cerebellar ataxia with amphiphysin antibody developing in a patient with follicular thyroid adenoma: a case report]

The patient was a 61-year-old woman with thyroid enlargement since her 20s. She began to fall down repeatedly towards the end of June 2015. She was admitted to our hospital in the middle of August because of difficulty in walking. Upon admission, she presented with neck tremor and was unable to maintain a sitting position due to ataxia of the trunk and limbs. We studied serum anti-neuronal antibodies and obtained a positive result for anti-amphiphysin antibody (AMPH-Ab). Cerebrospinal fluid analysis revealed elevated protein levels and IgG index. Other than the thyroid mass, a tumor was not detected. The resected thyroid specimen showed follicular adenoma. After performing immunotherapies, the cerebrospinal fluid protein levels and IgG index decreased, and her ataxia did not progress. When subacute cerebellar ataxia is suspected, studying AMPH-Ab should be considered.

Marked inflammation in catastrophic longitudinal myelitis associated with systemic lupus erythematosus

Catastrophic longitudinal myelitis is an extremely rare neurologic manifestation of collagen vascular disease, described heretofore in 11 cases of SLE and 1 of Sjogren's Syndrome. This report documents markedly abnormal and worsening CSF findings on sequential CSF examinations over a period of three days (WBC >1500 cells/μL, >80% neutrophils, markedly elevated protein, and extremely low glucose levels) in the absence of infection. These abnormalities cleared rapidly with institution of immunosuppressive therapy so that a third CSF exam done within three days revealed almost complete normalization of CSF values. These findings suggest that in some cases of CLM a strong inflammatory component may be present, while in others, other pathogenic factors may predominate. Lupus (2007) 16, 823—826.

Improved resolution of human cerebrospinal fluid proteins on two-dimensional gels

Proteomics combines two-dimensional gel electro phoresis and peptide mass fingerprinting and can potentially identify a protein(s) unique to disease. Such proteins can be used either for diagnosis or may be relevant to the pathogenesis of disease. Because patients with multiple sclerosis (MS) have increased amounts of immunoglobulin (Ig) G in their cerebrospinal fluid (C SF) that is directed against an as yet unidentified protein, we are applying proteomics to MS C SF, studies that require optimal separation of proteins in human C SF. We found that recovery of proteins from C SF of MS patients was improved using ultrafiltration, rather than dialysis, for desalting. Resolution of these proteins was enhanced by aceto ne precipitatio n of desalted C SF before electrophoresis and by fractionation of C SF using C ibacron Blue sepharose affinity chromatography. Improved protein recovery and resolution will facilitate excision from gels for analysis by peptide mass fingerprinting.

Method of intracranial pressure monitoring and cerebrospinal fluid sampling in swine

Cerebral oedema and encephalopathy have been noted to occur frequently in patients severely ill or dying after trauma, ischaemia, infections or even metabolic disorders. The objective of the present study was to establish continuous monitoring of the intracranial pressure (ICP) and sampling of cerebrospinal fluid (CSF) for further investigations in swine.

ICP monitoring was established in eight pigs by using a ventricular drainage system, implemented after paramedian trepanation of the os frontale. CSF and serum samples were taken for measurement of the levels of glucose and protein.

Operating time was 21±8 min for the trepanation until ICP monitoring was performed. No complications occurred during surgery. Continuous monitoring of ICP and CSF sampling was easy to perform, and without any side-effects in any animal. At autopsy, no iatrogenic lesions were found and monitoring catheters were still in place.

For several types of research requiring ICP monitoring and sampling of CSF, this method can be used successfully.

URGENT DIAGNOSTICS OF CEREBRAL VENOUS TROMBOSIS

Investigations were carried out in 24 patients in order to evaluate information value of the data of clinical, laboratory, neuroradiological methods of research and develop the diagnostic algorithm in case of cerebral venous thrombosis (CVT). The main group consisted of 11 patients (7 male, 4 female, average age 49,1±4,3) with CVT. The comparison group included 13 patients (6 male, 7 female; average age 68,1±9,5) with ischemic stroke (IS) of moderate severity. There were revealed changes in blood and cerebrospinal fluid (CSF) as form of leukocytosis of blood and moderately increased cell count with elevated protein in CSF and blood in case of CTV. The authors noted an elevated protein in CSF and blood and leukocytosis with predominant lymphopenia in blood and neurophilic predominance in CSF within the reference range of CSF in patient with ischemic stroke. The epileptic attacks, meningeal syndromes, headaches were more often among clinical syndromes at CTV than in case of ischemic stroke. The algorithm of neuroimaging research methods and modes of MRI were determined and allowed an effective diagnostics of damages of venous sinuses, superficial and deep cerebral veins in case of urgent hospitalization of patients. It was possible to suggest the venous pathology in 7 (63,6%) cases due to SKT (without contrast) and in case of application of MR venography (2D TOFmode), there were revealed 100% of cases.

Differential proteomics analysis of mononuclear cells in cerebrospinal fluid of Parkinson's disease

Parkinson's disease (PD) is one common neurodegenerative disease featured with degeneration of dopaminergic neurons in substantia nigra. Multiple factors participate in the pathogenesis and progression of PD. In this study, we investigated the proteomics profiles of mononuclear cells in cerebrospinal fluids from both PD patients and normal people, in order to explore the correlation between disease factors and PD. Cerebrospinal fluid samples were collected from both PD and normal people and were separated for mononuclear cells in vitro. Proteins were then extracted and separated by 2-dimensional gel electrophoresis. Proteins with differential expressions were identified by comparison to standard proteome expression profile map, followed by software and database analysis. In PD patients, there were 8 proteins with consistent expression profile and 16 proteins with differential expressions. Those differential proteins identified include cytoskeleton proteins (actin, myosin), signal transduction proteins (adenosine cyclase binding protein 1, calcium binding protein, talin) and anti-oxidation factor (thioredoxin peroxide reductase). PD patients had differential protein expressional profiles in the mononuclear cells of cerebrospinal fluids compared to normal people, suggesting the potential involvement of cytoskeleton and signal transduction proteins in apoptosis of neuronal apoptosis and PD pathogenesis.

Albuminocytologic Dissociation in Posterior Reversible Encephalopathy Syndrome

OBJECTIVES

To describe cerebrospinal fluid (CSF) findings in patients with posterior reversible encephalopathy syndrome (PRES) and to study its association with vasogenic edema.

PATIENTS AND METHODS

Retrospective review of 73 consecutive prospectively collected adults diagnosed with PRES from January 1, 2000, through December 31, 2014, who underwent lumbar puncture.

RESULTS

Seventy-three patients (mean age, 51±17 years), were included in the analysis; of these, 50 (69%) were women. The most common causes for PRES were hypertension (n=61 [84%]) and immunosuppression (n=22 [30%]). Renal failure was present in 42 (58%) patients. The median interval between clinical onset of PRES and CSF analysis was 1 day (interquartile range [IQR], 0-2 days). The median opening pressure was 23 cm H2O or 17 mm Hg (IQR, 18-28 cm H2O or 13-21 mm Hg), although it was available in only 27 patients. The median CSF protein level was 58 mg/dL (IQR, 44-81 mg/dL; normal value, <35 mg/dL). The median CSF protein level was higher in patients with more extensive vasogenic edema. The median white blood cell count was 1 cell/μL (IQR, 1-2 cells/μL).

CONCLUSION

Elevated CSF protein level without CSF pleocytosis commonly occurs in patients with PRES and is directly associated with the extent and topographical distribution of cerebral edema. Although mild CSF pleocytosis can also occur, it is an uncommon finding and may prompt consideration for further diagnostic testing.

Guillain-Barré syndrome: clinical profile and management

INTRODUCTION

Guillain-Barré syndrome (GBS) is a fulminant polyradiculoneuropathy that is acute, frequently severe and autoimmune in nature. Etiology of GBS is incompletely understood, prognosis is usually good with early detection and prompt treatment. This retrospective study was done to evaluate clinical profile, epidemiological, laboratory, and electrodiagnostic features of patients with GBS and mode of management, complications and prognostic factors.

METHODS

Data of 1,166 patients admitted with GBS or presented to outpatient department (previous medical records) with GBS between January 2003 and January 2014 were analyzed.

RESULTS

No difference in genders noted. Around 35% of patients are above 50 years of age. Poor control of diabetes with mean HbA1c of 8.1 ± 2.11 is found on analysis. Seasonal occurrence in GBS is prominent in winter 484 (41.50%) and mechanically ventilated were 449 (38.50%) patients. 48 (4.11%) deaths were attributed to GBS. Neurological analysis revealed cranial nerve involvement in 407 (34.90%) patients, facial palsy in 401 (34.39%) and ataxia in 88 (7.54%) patients. Most patients in plasma exchange group belonged to the lower socio-economic status. Mean cerebrospinal fluid (CSF) protein levels was (n=962) 113.8 ± 11.8 mg/dl. Conduction block determined indirectly by absent H-reflex was noted in 891 (90.64%) patients. No difference in complications and outcome is found in treatment regimens of intravenous immunoglobulin (IVIG) and plasma exchange.

CONCLUSION

Seasonal occurrence predominantly in winter is noted. Peak flow test may be a predictor of assessing requirement of mechanical ventilation and prognosis. Conduction block is the major abnormality noted in electrophysiological studies and proximal nerve segment assessing with Erb's point stimulation has high predictive value. IVIG treatment is more expensive but is associated with less duration of hospital stay.

Brillouin spectroscopy as a new method of screening for increased CSF total protein during bacterial meningitis

Bacterial meningitis is a disease of pronounced clinical significance, especially in the developing world. Immediate treatment with antibiotics is essential, and no single test can provide a conclusive diagnosis. It is well established that elevated total protein in cerebrospinal fluid (CSF) is associated with bacterial meningitis. Brillouin spectroscopy is a widely used optical technique for noninvasive determination of the elastic moduli of materials. We found that elevated protein levels in CSF alter the fluid elasticity sufficiently to be measurable by Brillouin spectroscopy, with model healthy and diseased fluids distinguishable to marked significance (P = 0.014), which increases with sample concentration by dialysis. Typical raw output of a 2-stage VIPA Brillouin spectrometer: inelastically scattered Brillouin peaks (arrows) and elastically scattered incident radiation (center cross).

Differential disruption of blood-brain barrier in severe traumatic brain injury

BACKGROUND

Traumatic brain injury (TBI) is a significant cause of death and disability in young adults, but not much is known about the incidence and characteristics of blood-brain barrier (BBB) dysfunction in this group. In this proof of concept study, we sought to quantify the incidence of BBB dysfunction (defined as a cerebrospinal fluid (CSF)-plasma albumin quotient of ≥0.007) and examine the relationship between plasma and CSF levels of proteins and electrolytes, in patients with severe TBI.

METHODS

We recruited 30 patients, all of whom were receiving hypertonic 20 % saline infusion for intracranial hypertension and had external ventricular drains in situ. Simultaneous CSF and blood samples were obtained. Biochemical testing was performed for sodium, osmolality, potassium, glucose, albumin, immunoglobulin-G, and total protein.

RESULTS

Eleven patients (37 %) showed evidence of impairment of passive BBB function, with a CSF-plasma albumin quotient of ≥0.007. There were strong positive correlations seen among CSF-plasma albumin quotient and CSF-plasma immunoglobulin-G quotient and CSF-plasma total protein quotient (r = 0.967, P < 0.001 and r = 0.995, P < 0.001, respectively). We also found a higher maximum intracranial pressure (24 vs. 21 mmHg, P = 0.029) and a trend toward increased mortality (27 vs. 11 %, P = 0.33) in patients with BBB disruption.

CONCLUSIONS

In summary, passive BBB dysfunction is common in patients with severe TBI, and may have important implications for effectiveness of osmotherapy and long-term outcomes. Also, our results suggest that the CSF-plasma total protein quotient, a measurement which is readily available, can be used instead of the CSF-plasma albumin quotient for evaluating BBB dysfunction.

Mass spectrometric analysis of rat cerebrospinal fluid proteins following exposure to the neurotoxicant carbonyl sulfide

RATIONALE

Using a proteomic-based approach we have investigated possible altered expression of a range of cerebral spinal fluid (CSF) proteins following exposure to the neurotoxicant carbonyl sulfide (COS). CSF is ideal for the investigation of markers of brain injury or disease since it is secreted from several central nervous system structures and changes in the CSF composition may reflect brain insult and many pathological processes.

METHODS

Animals were placed in exposure chambers and were exposed to 0 ppm or 500 ppm COS for 1, 2 or 3 days, 6 h per day. After the last inhalation exposure, 50-70 μL CSF sample was obtained by lumbar puncture. CSF samples were analyzed by electrospray ionization mass spectrometry (ESI-MS) on either a Premier quadrupole time-of-flight (QTOF) or an Agilent 6340 ion trap and by matrix-assisted laser desorption/ionization (MALDI)-MS on a 4800 MALDI-TOF/TOF analyzer.

RESULTS

The dynamic range of abundance of the identified proteins spanned over more than three orders of magnitude. The four most abundant proteins identified (albumin, cystatin C, serotransferrin, transthyretin) are major proteins that are present in both CSF and blood at high levels but the fifth most abundant protein identified (prostaglandin H2D isomerase) is the second most abundant protein in human CSF and is secreted and synthesized in the rat central nervous system. No significant differences were observed between COS-treated CSF samples and the control CSF samples because of blood contamination.

CONCLUSIONS

Quantitative MS protein analyses of rat CSF is limited by the low sample volumes that can practicably be obtained from rats and the low protein concentrations in rat CSF. Results of this work suggest a clear need for CSF collection that would minimize blood contamination. Published in 2014. This article is a U.S. Government work and is in the public domain in the USA.

Peptide profiling of cerebrospinal fluid by mass spectrometry

The search for biomarkers is driven by the increasing clinical importance of early diagnosis. Reliable biomarkers can also assist in directing therapy, monitoring disease activity and the efficacy of treatment. In addition, the discovery of novel biomarkers might provide clues to the pathogenesis of a disease. The dynamic range of protein concentrations in body fluids exceeds 10 orders of magnitude. These huge differences in concentrations complicate the detection of proteins with low expression levels. Since all classical biomarkers have low expression levels (e.g., prostate-specific antigen: 2-4 microg/l; and CA125: 20-35 U/ml), new developments with respect to identification and validation techniques of the low-abundance proteins are required. This review will discuss the current status of profiling cerebrospinal fluid using mass spectrometry-based techniques, and new developments in this area.

[Clinico-radiological profile of acute disseminated encephalomyelitis in the childhood population. A retrospective analysis of a series of 20 patients in a tertiary hospital]

INTRODUCTION

Acute disseminated encephalomyelitis (ADE) is an inflammatory disorder of the central nervous system that is mediated immunologically and of unknown pathogenesis. It can present at any age, but is much more frequent in children. ADE has no specific biological marker and diagnosis is based on findings from clinical and neuroimaging studies.

AIM

To enhance our knowledge of the clinico-radiological profile of this disease.

PATIENTS AND METHODS

This retrospective study involved patients under 14 years of age who were admitted to a tertiary hospital over the last 15 years with a diagnosis of ADE. History, clinical presenting symptoms, lab findings from blood/cerebrospinal fluid analyses and radiological semiology were reviewed. In 16 cases an average follow-up of 25 months was performed.

RESULTS

The study examined 20 patients, 70% children, with a mean age of 4.4 years. Forty per cent had a previous febrile episode. Eighty-five per cent presented fever or vomiting, and 70% had altered states of mind. Motor deficits (45%), convulsions (35%) and involvement of the cranial nerves (30%) were predominant. Three children progressed with relapses and three others were left with motor sequelae. Magnetic resonance imaging showed hyperintense lesions in T2, with a pattern of scarce/no enhancement, which were predominantly located in the thalamus (70%), the spinal cord (67%) and the white matter of the sub-cortex (50%). Haemorrhagic ADE was diagnosed in two patients.

CONCLUSIONS

ADE is a condition with an important degree of general involvement and neurological repercussions, as well as considerable potential to leave the patient with sequelae. Clinico-analytical data and magnetic resonance scans of the head and spinal cord are relevant for the initial diagnosis and follow-up of patients with ADE.

[Biomarkers in multiple sclerosis]

Multiple sclerosis is the most frequent disabling neurological disease in young adults. Its development includes independent processes of inflammation, demyelination, neurodegeneration, gliosis and repair, which are responsible for the heterogeneity and individual variability in the expression of the disease, its prognosis and response to treatment. As part of personalised medicine, the progress made in the search for new biomarkers has identified promising candidates that may be useful for the early diagnosis of the disease, for detecting prognostic and developmental profiles of the disease, and for monitoring the response to treatment. Unfortunately, few of them have been validated adequately, which prevents them from being applied in clinical practice. In view of the latest findings, the experts recommend orienting research in another direction, not so much towards the discovery of new molecules or imaging techniques, but instead towards a clinical validation of these markers, with the aim of fostering translational research. This review offers an update on the information about the biomarkers in multiple sclerosis that have currently been validated and are thus potential candidates, as well as looking at their value in the diagnosis, prognosis, evaluation of the development of the disability caused by the disease and the response to therapy.

Comparison of clinical and CSF profiles in children with tuberculous and pyogenic meningitis; role of CSF protein: glucose ratio as diagnostic marker of tuberculous meningitis

OBJECTIVES

To compare the clinical and laboratory features of tuberculous meningitis with bacterial meningitis and to determine if protein glucose ratio in the cerebrospinal fluid can be predictive of the condition.

METHODS

It was a retrospective descriptive study at the Paediatric Ward of Aga Khan University Hospital, Karachi, for which records of 46 patients with tuberculous meningitis and 33 with bacterial meningitis were reviewed. All records related to the study period that was from January 2005 to October 2010. The records were retrieved in December 2010. Tuberculous meningitis was defined as illness > or = 14 days, basal enhancement or tuberculoma on computerised tomography scan and response to anti-tuberculous therapy. Pyogenic meningitis was defined by the presence of a pathogenic isolate inthe cerebrospinal fluid (bacterial culture) or by positive latex particle agglutination or a pathogen on cerebrospinal fluid gram stain and clinical improvement with antibiotics. Logistic regression was used to model the probability of having tuberculous meningitis. To define the optimal protein-glucose ratio, cutoff point for the diagnosis of tuberculous meningitis, a receiver operating characteristic curve was applied. All analysis were done using SPSS 16.

RESULTS

Features predictive of a diagnosis of tuberculous meningitis were protein:glucose ratio of > or = 2 (OR 21 95% CI 4.7-93); cerebrospinal fluid total leukocyte count < 800 (OR 58, 95% CI 5-649); and the presence of hydrocephalus (OR 19, 95% CI 3.3-109).

CONCLUSION

A set of simple clinical, laboratory and radiological criteria can help in predicting tuberculous meningitis. The value of cerebrospinal fluid protein:glucose ratio needs to be validated in larger studies with bacteriologically-confirmed cases of tuberculous meningitis.

Preparation of human cerebrospinal fluid for proteomics biomarker analysis

The analysis of the cerebrospinal fluid (CSF) proteome in recent years has resulted in a valuable repository of data for targeting and diagnosing a variety of diseases, such as Parkinson's disease, Alzheimer's disease, traumatic brain injury, and amyotrophic lateral sclerosis. Human ventricular CSF contains numerous proteins that are unique to CSF due in part to the interaction of the biofluid with the brain. This allows researchers to obtain information from a region that would otherwise be inaccessible except through invasive surgery or during autopsy. Characterization of the CSF proteome requires that strict care be taken so that sample integrity and fidelity are maintained to ensure data reproducibility. Standardized methods in sample collection, storage, preparation, analysis, and data mining must be used for meaningful information to be obtained. The following method describes a simple and robust approach for preparing CSF samples for analysis via reversed-phase liquid chromatography (RPLC) and mass spectrometry (MS).

Monitoring CSF proteome alterations in amyotrophic lateral sclerosis: obstacles and perspectives in translating a novel marker panel to the clinic

Background

Amyotrophic lateral sclerosis (ALS) is a fatal disorder of the motor neuron system with poor prognosis and marginal therapeutic options. Current clinical diagnostic criteria are based on electrophysiological examination and exclusion of other ALS-mimicking conditions. Neuroprotective treatments are, however, most promising in early disease stages. Identification of disease-specific CSF biomarkers and associated biochemical pathways is therefore most relevant to monitor disease progression, response to neuroprotective agents and to enable early inclusion of patients into clinical trials.

Methods and Findings

CSF from 35 patients with ALS diagnosed according to the revised El Escorial criteria and 23 age-matched controls was processed using paramagnetic bead chromatography for protein isolation and subsequently analyzed by MALDI-TOF mass spectrometry. CSF protein profiles were integrated into a Random Forest model constructed from 153 mass peaks. After reducing this peak set to the top 25%, a classifier was built which enabled prediction of ALS with high accuracy, sensitivity and specificity. Further analysis of the identified peptides resulted in a panel of five highly sensitive ALS biomarkers. Upregulation of secreted phosphoprotein 1 in ALS-CSF samples was confirmed by univariate analysis of ELISA and mass spectrometry data. Further quantitative validation of the five biomarkers was achieved in an 80-plex Multiple Reaction Monitoring mass spectrometry assay.

Conclusions

ALS classification based on the CSF biomarker panel proposed in this study could become a valuable predictive tool for early clinical risk stratification. Of the numerous CSF proteins identified, many have putative roles in ALS-related metabolic processes, particularly in chromogranin-mediated secretion signaling pathways. While a stand-alone clinical application of this classifier will only be possible after further validation and a multicenter trial, it could be readily used to complement current ALS diagnostics and might also provide new insights into the pathomechanisms of this disease in the future.

Plasma and Cerebrospinal Fluid-Based Protein Biomarkers for Motor Neuron Disease

Motor neuron diseases (MNDs) and, in particular, amyotrophic lateral sclerosis (ALS), are a heterogeneous group of neurologic disorders characterized by the progressive loss of motor function. In ALS, a selective and relentless degeneration of both upper and lower motor neurons occurs, culminating in mortality typically within 5 years of symptom onset. However, survival rates vary among individual patients and can be from a few months to >10 years from diagnosis. Inadequacies in disease detection and treatment, along with a lack of diagnostic and prognostic tools, have prompted many to turn to proteomics-based biomarker discovery efforts. Proteomics refers to the study of the proteins expressed by a genome at a particular time, and the proteome can respond to and reflect the status of an organism, including health and disease states. Although an emerging field, proteomic applications promise to uncover biomarkers critical for differentiating patients with ALS and other MNDs from healthy individuals and from patients affected by other diseases. Ideally, these studies will also provide mechanistic information to facilitate identification of new drug targets for subsequent therapeutic development. In addition to proper experimental design, standard operating procedures for sample acquisition, preprocessing, and storage must be developed. Biological samples typically analyzed in proteomic studies of neurologic diseases include both plasma and cerebrospinal fluid (CSF). Recent studies have identified individual proteins and/or protein panels from blood plasma and CSF that represent putative biomarkers for ALS, although many of these proteins are not unique to this disease. Continued investigations are required to validate these initial findings and to further pursue the role of these proteins as diagnostic biomarkers or surrogate markers of disease progression. Protein biomarkers specific to ALS will additionally function to evaluate drug efficacy in clinical trials and to identify novel targets for drug design. It is hoped that proteomic technologies will soon integrate the basic biology of ALS with mechanistic disease information to achieve success in the clinical setting.

Heligmosomoides polygyrus: EAE remission is correlated with different systemic cytokine profiles provoked by L4 and adult nematodes

Primary exposure of mice to gastrointestinal nematode infection with Heligmosomoides polygyrus reduces inflammation in an experimental model of multiple sclerosis. In this study, we aimed to evaluate the ability of H. polygyrus L4 larvae and adults infection to reduce the symptoms of ongoing experimental autoimmune encephalomyelitis (EAE) in female C57Bl/6 mice. EAE was induced by myelin oligodendrocyte glycoprotein MOG(p35-55) and after 21 days mice were orally infected with 200 infective larvae (L3) of H. polygyrus. Reduction in EAE symptoms was observed from 2 days post infection and the symptoms were almost completely inhibited at 6 days post infection. This effect was associated with limited total protein content in the cerebrospinal fluid; CSF, and significant decreased pro-inflammatory IL-12p40 concentration and increased concentration of the regulatory cytokines IL-10, TGF-β and IL-6 in the CSF and in the serum. The reduction of EAE symptoms in the enteral phase was associated with higher IL-12p40 concentration in the CSF and very low concentrations of IL-17A and IL-2 in the serum. The fourth stage of gastrointestinal nematode can reverse systemic inflammation in animal models of multiple sclerosis by reducing IL-12 and promoting regulatory cytokines production. The mechanism induced by adult nematodes which sustained EAE inhibition can be provoked by regulatory mechanism connected with reduce IL-17A concentration.

Thoracic myelopathy due to calcification of the ligamentum flavum with hyperproteinorachia and responsive to steroid therapy: case report

Calcification and ossification of the ligamentum flavum or of the posterior longitudinal ligament are causes of compressive myelopathy, more frequent in the lower thoracic levels, and extremely rare in Western populations. Surgical decompression is the only therapy, but the disease is usually progressive, and its recurrence after surgery is common. Inflammatory mediators might play a role in the progression of compressive myelopathy, but, to our knowledge, the therapeutic approach involving anti-inflammatory agents has never been tried before. We report a case of compressive myelopathy due to calcification of the ligamentum flavum, in which hyperproteinorachia and response to steroid therapy have been observed. Those data have not been published before and might provide new ideas for the disease understanding.

Age-dependent changes in the cerebrospinal fluid proteome by slow off-rate modified aptamer array

An important precondition for the successful development of diagnostic assays of cerebrospinal fluid (CSF) biomarkers of age-related neurodegenerative diseases is an understanding of the dynamic nature of the CSF proteome during the normal aging process. In this study, a novel proteomic technology was used to quantify hundreds of proteins simultaneously in the CSF from 90 cognitively normal adults 21 to 85 years of age. SomaLogic's highly multiplexed proteomic platform can measure more than 800 proteins simultaneously from small volumes of biological fluids using novel slow off-rate modified aptamer (SOMAmer) protein affinity reagents with sensitivity, specificity, and dynamic ranges that meet or exceed those of enzyme-linked immunosorbent assays. In the first application of this technology to CSF, we detected 248 proteins that possessed signals greater than twofold over background. Several novel correlations between detected protein concentrations and age were discovered that indicate that both inflammation and response to injury in the central nervous system may increase with age. Applying this powerful proteomic approach to CSF provides potential new insight into the aging of the human central nervous system that may have utility in discovering new disease-related changes in the CSF proteome.

Protein biomarkers for multiple sclerosis: semi-quantitative analysis of cerebrospinal fluid candidate protein biomarkers in different forms of multiple sclerosis

BACKGROUND

The complex pathogenesis of multiple sclerosis, combined with an unpredictable prognosis, requires identification of disease-specific diagnostic and prognostic biomarkers.

OBJECTIVE

To determine whether inflammatory proteins, such as neurofilament light chain, myelin oligodendrocyte glycoprotein and myelin basic protein, and neurodegenerative proteins, such as tau and glial fibrillary acidic protein, can serve as biomarkers for predicting the clinical subtype and prognosis of MS.

METHODS

Cerebrospinal fluid and serum samples were collected from patients with a diagnosis of clinically isolated syndrome (n = 46), relapsing-remitting MS (n = 67) or primary-progressive MS (n = 22) along with controls having other non-inflammatory neurological disease (n = 22). Western blot analyses were performed for the listed proteins. Protein levels were compared among different clinical subtypes using one-way analysis of variance analysis. The k-nearest neighbour algorithm was further used to assess the predictive use of these proteins for clinical subtype classification.

RESULTS

The results showed that each of tau, GFAP, MOG and NFL protein concentrations differed significantly (p < 0.001) in multiple sclerosis clinical subtypes compared with the controls. Levels of the proteins also differed between the multiple sclerosis clinical subtypes, which may be associated with the underlying disease process. Classification studies revealed that these proteins might be useful for identifying multiple sclerosis clinical subtypes.

CONCLUSIONS

We showed that select biomarkers may have potential in identifying multiple sclerosis clinical subtypes. We also showed that the predictive value of the prognosis increased when using a combination of the proteins versus using them individually.

Protein profiling of cerebrospinal fluid

The cerebrospinal fluid (CSF) perfuses the brain and spinal cord. CSF contains proteins and peptides important for brain physiology and potentially also relevant for brain pathology. Hence, CSF is the perfect source to search for new biomarkers to improve diagnosis of neurological diseases as well as to monitor the performance of disease-modifying drugs. This chapter presents methods for SELDI-TOF profiling of CSF as well as useful advice regarding pre-analytical factors to be considered.

How appropriate are cerebrospinal fluid polymerase chain reaction requests for suspected central nervous system infections?

Cerebrospinal fluid (CSF) polymerase chain reaction (PCR) assays have become the main diagnostic tests for central nervous system viral infections in recent years. Previous studies have suggested algorithms based on CSF leukocyte count and total protein levels to determine when CSF PCR assays are indicated. Based on these criteria, 1,469 CSF PCR tests requested over a two-year period were reviewed. A proportion of positive PCR results were found in children with normal CSF, unlike in adults where such occurrences were extremely rare. The results suggest that applying a strategy of screening CSF specimens using leukocyte count, glucose and protein, at least in adults, may have avoided more than half of CSF PCR requests with little detriment to patient care and considerable cost savings. Larger prospective studies are needed to determine whether algorithms using standard CSF parameters and clinical information can optimise the use of CSF PCR assays in clinical practice.