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Background Neurosarcoidosis (NS) is a rare condition that may mimic central nervous system (CNS) infection, neoplasia and other inflammatory disorders of the CNS such as multiple sclerosis, encephalitis and vasculitis. Diagnosis is challenging in cases with minimal or absent systemic involvement. Cerebrospinal fluid (CSF) angiotensin-converting enzyme (c-ACE) has been claimed as a valuable diagnostic tool for NS. However, there is little data evaluating its performance in routine clinical practice. Findings We performed a monocentric, retrospective, chart-based study including all patients investigated with a lumbar puncture and c-ACE dosage for suspected NS between 01/01/2006 and 31/12/2012 at the Geneva University Hospital. Receiver-operating characteristic (ROC) curve and area under the curve (AUC) were performed to calculate the optimal cut-off value of c-ACE and to determine the discriminative ability of c-ACE. Of the 440 patients included in the study, 9 were diagnosed with NS on the basis of tissue biopsy. Mean c-ACE was not significantly different between NS and non-NS patients. With a cut-off value of 2 (0–2 vs ≥ 3), sensitivity and specificity of c-ACE were 66.7% and 67.3%, respectively. Conclusions In our clinical setting, the sensitivity and specificity of c-ACE for NS diagnosis were relatively poor and of little clinical utility.

Our objective was to evaluate the CSF phospho-Tau181/total-Tau (p/t-Tau) ratio to distinguish between the two main forms of frontotemporal lobar degeneration (FTLD): FTLD with TDP-43 (FTLD-TDP) and FTLD with Tau inclusions (FTLD-Tau). CSF p/t-Tau ratio was examined in 79 FTLD patients with predictable neuropathology, i.e. Tau (affected by progressive supranuclear palsy or carriers of mutations within the MAPT gene) or TDP-43 (carriers of mutations within granulin, C9orf72, TARDBP genes or affected by FTD with motor neuron disease). FTLD patients were randomly grouped in a training cohort (n = 39) to assess the best CSF p/t-Tau cut-off score according to ROC analysis, and a validation cohort (n = 40) to evaluate accuracy values of the identified marker. Results showed that, in the training cohort, we found a significantly reduced CSF p/t-Tau ratio in FTLD-TDP relative to FTLD-Tau. ROC analysis for p/t-Tau ratio was 0.873 and cut-off score of 0.136 allowed to differentiate FTLD-TDP and FTLD-Tau with 81.8% sensitivity and 88.2% specificity, respectively. Analysis in the validation cohort showed CSF p/t-Tau ratio < 0.136 to distinguish FTLD-TDP from FTLD-Tau with 83.3% specificity and 63.6% sensitivity, respectively. The positive predictive value of detecting TDP neuropathology was 82.4%. In conclusion, a reduced CSF p/t-Tau ratio represents a viable biomarker to correctly identify TDP pathology in FTLD.

Following any form of brain insult, proteins are released from damaged tissues into the cerebrospinal fluid (CSF). This body fluid is therefore an ideal sample to use in the search for biomarkers of neurodegenerative disorders and brain damage. In this study, we used human post-mortem CSF as a model of massive brain injury and cell death for the identification of such protein markers. Pooled post-mortem CSF samples were analyzed using a protocol that combined immunoaffinity depletion of abundant CSF proteins, off-gel electrophoresis, SDS-PAGE and protein identification by LC-MS/MS. A total of 299 proteins were identified, of which 172 proteins were not previously described to be present in CSF. Of these 172 proteins, more than 75% have been described as intracellular proteins suggesting that they were released from damaged cells. Immunoblots of a number of proteins were performed on individual post-mortem CSF samples and confirmed elevated concentrations in post-mortem CSF compared to ante-mortem CSF. Interestingly, among the proteins specifically identified in the post-mortem CSF, several have been previously described as biochemical markers of brain damage.

Objectives A critical step before treatment of human African trypanosomiasis (HAT) is the correct staging of the disease. As late stage is established when trypanosomes cross the blood-brain barrier and invade the central nervous system, we hypothesized that matrix metalloproteinases and cell adhesion molecules could indicate, alone or in combination, the disease progression from the first to the second stage of HAT. Methods We measured the levels of MMP-2, MMP-9, ICAM-1, VCAM-1 and E-selectin in the cerebrospinal fluid (CSF) of 63 Trypanosoma brucei gambiense-infected patients (15 stage 1 and 48 stage 2). Staging was based on counting of white blood cells (WBC) and/or parasite detection in CSF. Concentrations were obtained either by ELISA or multiplex bead suspension assays, and results were compared with three known HAT staging markers (CXCL10, CXCL8 and H-FABP). Results ICAM-1 and MMP-9 accurately discriminated between stage 1 and stage 2 patients with HAT with 95% sensitivity (SE) for 100% specificity (SP), which was better than CXCL10 (93% SE for 100% SP), one of the most promising known markers. Combination of ICAM-1 and MMP-9 with H-FABP provided a panel that resulted in 100% of SE and SP for staging HAT. Conclusions ICAM-1 and MMP-9, alone or in combination, appeared as powerful CSF staging markers of HAT. Final validation of all newly discovered staging markers on a large multi-centric cohort including both forms of the disease as well as patients with others infections should be performed.

Quantification is a major task in proteomics. Among the different analytical strategies to enable peptide and protein quantification, tagging with isotopic labels has emerged as a practical, versatile, and efficient alternative. In particular, isobaric labels, such as TMT or iTRAQ, are now widely employed to make relative comparison of the protein amounts in separate biological samples with tandem mass spectrometry (MS/MS). We used herein a shotgun proteomic approach based on labelling with tandem mass tags (TMTs) for the relative quantification of proteins, and the absolute quantification of their tryptic peptides in human cerebrospinal fluid (CSF). First, the comparison of ante- and post-mortem CSF samples was carried out for the discovery of protein marker candidates of brain-damage disorders. Second, tryptic peptides representative of these candidates were measured in CSF using reporter-ion calibration curves. These works highlighted the advantages and limitations of such strategies for quantification purposes in proteomics.

Background Human African trypanosomiasis (HAT), also known as sleeping sickness, is a parasitic tropical disease. It progresses from the first, haemolymphatic stage to a neurological second stage due to invasion of parasites into the central nervous system (CNS). As treatment depends on the stage of disease, there is a critical need for tools that efficiently discriminate the two stages of HAT. We hypothesized that markers of brain damage discovered by proteomic strategies and inflammation-related proteins could individually or in combination indicate the CNS invasion by the parasite. Methods Cerebrospinal fluid (CSF) originated from parasitologically confirmed Trypanosoma brucei gambiense patients. Patients were staged on the basis of CSF white blood cell (WBC) count and presence of parasites in CSF. One hundred samples were analysed: 21 from stage 1 (no trypanosomes in CSF and ≤5 WBC/µL) and 79 from stage 2 (trypanosomes in CSF and/or >5 WBC/µL) patients. The concentration of H-FABP, GSTP-1 and S100β in CSF was measured by ELISA. The levels of thirteen inflammation-related proteins (IL-1ra, IL-1β, IL-6, IL-9, IL-10, G-CSF, VEGF, IFN-γ, TNF-α, CCL2, CCL4, CXCL8 and CXCL10) were determined by bead suspension arrays. Results CXCL10 most accurately distinguished stage 1 and stage 2 patients, with a sensitivity of 84% and specificity of 100%. Rule Induction Like (RIL) analysis defined a panel characterized by CXCL10, CXCL8 and H-FABP that improved the detection of stage 2 patients to 97% sensitivity and 100% specificity. Conclusion This study highlights the value of CXCL10 as a single biomarker for staging T. b. gambiense-infected HAT patients. Further combination of CXCL10 with H-FABP and CXCL8 results in a panel that efficiently rules in stage 2 HAT patients. As these molecules could potentially be markers of other CNS infections and disorders, these results should be validated in a larger multi-centric cohort including other inflammatory diseases such as cerebral malaria and active tuberculosis., Author Summary The actual serological and parasitological tests used for the diagnosis of human African trypanosomiasis (HAT), also known as sleeping sickness, are not sensitive and specific enough. The card agglutination test for trypanosomiasis (CATT) assay, widely used for the diagnosis, is restricted to the gambiense form of the disease, and parasitological detection in the blood and cerebrospinal fluid (CSF) is often very difficult. Another very important problem is the difficulty of staging the disease, a crucial step in the decision of the treatment to be given. While eflornithine is difficult to administer, melarsoprol is highly toxic with incidences of reactive encephalopathy as high as 20%. Staging, which could be diagnosed as early (stage 1) or late (stage 2), relies on the examination of CSF for the presence of parasite and/or white blood cell (WBC) counting. However, the parasite is rarely found in CSF and WBC count is not standardised (cutoff set between 5 and 20 WBC per µL). In the present study, we hypothesized that an early detection of stage 2 patients with one or several proteins in association with clinical evaluation and WBC count would improve staging accuracy and allow more appropriate therapeutic interventions.

Prostaglandin D2 synthase (PGDS) (beta-trace protein) is a highly abundant cerebrospinal fluid (CSF) glycoprotein. A number of studies have been performed to determine the potential value of this protein for the diagnosis of various neurological disorders. The measurement of total PGDS levels in CSF has proved marginally useful for this purpose, but promising results were obtained while investigating changes in the posttranslational modifications (PTM) pattern. Using 2-DE analysis, we previously showed that PGDS is differentially expressed in ante- and post mortem CSF samples. In the present study, we examined whether the PGDS isoforms may help to distinguish stroke and neurodegenerative disease patients from healthy subjects. The pattern of PGDS PTM was analyzed in CSF from patients with various neurological disorders (n = 44) using IEF/immunoblotting techniques. Strong alterations of this pattern were detected in patients with different forms of degenerative dementia. These findings are consistent with PGDS being altered in some neurological diseases and provide new opportunities for clinical applications.

The development of a validated primate model of progressive parkinsonism is a critical step in the evaluation of drugs that might halt or slow progression of Parkinson's disease. In this pilot study, we gradually exposed 14 cynomolgus monkeys to 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), at a weekly dose of 0.5 mg/kg s.c. for 10 weeks, to determine their probability of not reaching a predetermined endpoint on a disability scale by Kaplan–Meier analysis. Four other MPTP-exposed animals were coadministered the potent free radical scavenger 7-hydroxy-1-[4-(3-methoxyphenyl)-1-piperazinyl]acetylamino-2,2,4,6- tetramethylindan (OPC-14117) as a single oral daily dose of 0.6 g/kg, starting 2 weeks before MPTP initiation. The risk of reaching endpoint by week 10 was 79% and mean time before reaching endpoint was 6 weeks. Global motor activity, recorded in a subset of animals using a portable activity monitor, declined following the first MPTP dose and never recovered. Several cerebrospinal fluid indices of central monoamine metabolism collected by suboccipital puncture at 0, 5, and 10 weeks, including HVA, DOPAC, and tetrahydrobiopterin but not MHPG, were found to be “trait” markers for MPTP exposure, whereas CSF DOPAC and tetrahydrobiopterin constituted potential “state” markers for reaching endpoint. The antioxidant OPC-14117 did not protect against MPTP-induced parkinsonism. Further attempts to validate this incremental model of neurotoxin-induced parkinsonism as a predictor of patient responses to putative neuroprotective agents appear warranted.