NIR-II nanoprobes for investigating the glymphatic system function under anesthesia and stroke injury.

The glymphatic system plays an important role in the transportation of cerebrospinal fluid (CSF) and the clearance of metabolite waste in brain. However, current imaging modalities for studying the glymphatic system are limited. Herein, we apply NIR-II nanoprobes with non-invasive and high-contrast advantages to comprehensively explore the function of glymphatic system in mice under anesthesia and cerebral ischemia-reperfusion injury conditions. Our results show that the supplement drug dexmedetomidine (Dex) enhances CSF influx in the brain, decreases its outflow to mandibular lymph nodes, and leads to significant differences in CSF accumulation pattern in the spine compared to isoflurane (ISO) alone, while both ISO and Dex do not affect the clearance of tracer-filled CSF into blood circulation. Notably, we confirm the compromised glymphatic function after cerebral ischemia-reperfusion injury, leading to impaired glymphatic influx and reduced glymphatic efflux. This technique has great potential to elucidate the underlying mechanisms between the glymphatic system and central nervous system diseases.

Quantitative proteomics of cerebrospinal fluid from African Americans and Caucasians reveals shared and divergent changes in Alzheimer's disease.

BACKGROUND: Despite being twice as likely to get Alzheimer's disease (AD), African Americans have been grossly underrepresented in AD research. While emerging evidence indicates that African Americans with AD have lower cerebrospinal fluid (CSF) levels of Tau compared to Caucasians, other differences in AD CSF biomarkers have not been fully elucidated. Here, we performed unbiased proteomic profiling of CSF from African Americans and Caucasians with and without AD to identify both common and divergent AD CSF biomarkers. METHODS: Multiplex tandem mass tag-based mass spectrometry (TMT-MS) quantified 1,840 proteins from 105 control and 98 AD patients of which 100 identified as Caucasian while 103 identified as African American. We used differential protein expression and co-expression approaches to assess how changes in the CSF proteome are related to race and AD. Co-expression network analysis organized the CSF proteome into 14 modules associated with brain cell-types and biological pathways. A targeted mass spectrometry method, selected reaction monitoring (SRM), with heavy labeled internal standards was used to measure a panel of CSF module proteins across a subset of African Americans and Caucasians with or without AD. A receiver operating characteristic (ROC) curve analysis assessed the performance of each protein biomarker in differentiating controls and AD by race. RESULTS: Consistent with previous findings, the increase of Tau levels in AD was greater in Caucasians than in African Americans by both immunoassay and TMT-MS measurements. CSF modules which included 14-3-3 proteins (YWHAZ and YWHAG) demonstrated equivalent disease-related elevations in both African Americans and Caucasians with AD, whereas other modules demonstrated more profound disease changes within race. Modules enriched with proteins involved with glycolysis and neuronal/cytoskeletal proteins, including Tau, were more increased in Caucasians than in African Americans with AD. In contrast, a module enriched with synaptic proteins including VGF, SCG2, and NPTX2 was significantly lower in African Americans than Caucasians with AD. Following SRM and ROC analysis, VGF, SCG2, and NPTX2 were significantly better at classifying African Americans than Caucasians with AD. CONCLUSIONS: Our findings provide insight into additional protein biomarkers and pathways reflecting underlying brain pathology that are shared or differ by race.

A single-cell map of antisense oligonucleotide activity in the brain.

Antisense oligonucleotides (ASOs) dosed into cerebrospinal fluid (CSF) distribute broadly throughout the central nervous system (CNS). By modulating RNA, they hold the promise of targeting root molecular causes of disease and hold potential to treat myriad CNS disorders. Realization of this potential requires that ASOs must be active in the disease-relevant cells, and ideally, that monitorable biomarkers also reflect ASO activity in these cells. The biodistribution and activity of such centrally delivered ASOs have been deeply characterized in rodent and non-human primate (NHP) models, but usually only in bulk tissue, limiting our understanding of the distribution of ASO activity across individual cells and across diverse CNS cell types. Moreover, in human clinical trials, target engagement is usually monitorable only in a single compartment, CSF. We sought a deeper understanding of how individual cells and cell types contribute to bulk tissue signal in the CNS, and how these are linked to CSF biomarker outcomes. We employed single nucleus transcriptomics on tissue from mice treated with RNase H1 ASOs against Prnp and Malat1 and NHPs treated with an ASO against PRNP. Pharmacologic activity was observed in every cell type, though sometimes with substantial differences in magnitude. Single cell RNA count distributions implied target RNA suppression in every single sequenced cell, rather than intense knockdown in only some cells. Duration of action up to 12 weeks post-dose differed across cell types, being shorter in microglia than in neurons. Suppression in neurons was generally similar to, or more robust than, the bulk tissue. In macaques, PrP in CSF was lowered 40% in conjunction with PRNP knockdown across all cell types including neurons, arguing that a CSF biomarker readout is likely to reflect ASO pharmacodynamic effect in disease-relevant cells in a neuronal disorder. Our results provide a reference dataset for ASO activity distribution in the CNS and establish single nucleus sequencing as a method for evaluating cell type specificity of oligonucleotide therapeutics and other modalities.

Antisense oligonucleotide (ASO) drugs are a type of chemically modified DNA that can be injected into cerebrospinal fluid in order to enter brain cells and reduce the amount of RNA from a specific gene. The brain is a complex mixture of hundreds of billions of cells. When an ASO lowers a target gene's RNA by 50%, is that a 50% reduction in 100% of cells, or a 100% reduction in 50% of cells? Are the many different cell types of the brain affected equally? This new study uses single cell RNA sequencing to answer these questions, finding that ASOs are broadly active across cell types and individual cells, and linking reduction of target protein in cerebrospinal fluid to disease-relevant cells.

Liquid chromatography-tandem mass spectrometry analysis of delamanid and its metabolite in human cerebrospinal fluid using protein precipitation and on-line solid-phase extraction.

The penetration of the antituberculosis drug delamanid into the central nervous system is not established. The distribution of delamanid and its major metabolite, DM-6705, into the cerebrospinal fluid requires investigation. A liquid chromatography-tandem mass spectrometry method for the quantification of delamanid and DM-6705 in human cerebrospinal fluid was developed and validated. The calibration range for both analytes was 0.300 - 30.0 ng/mL. The deuterium-labelled analogue of delamanid (delamanid-d4) and OPC-14714 were used as internal standards for delamanid and DM-6705, respectively. Samples were processed by protein precipitation followed by on-line solid-phase extraction and high-performance liquid chromatography on an Agilent 1260 HPLC system. A Phenomenex Gemini-NX C18 (5.0 µm, 50 mm × 2.0 mm) analytical column was used for on-line solid-phase extraction, and a Waters Xterra MS C18 (5.0 µm, 100 mm × 2.1 mm) analytical column for chromatographic separation using gradient elution, at a flow rate of 300 µL/min. The total run time was 7.5 min. Analytes were detected by multiple reaction monitoring on an AB Sciex 5500 triple quadrupole mass spectrometer at unit mass resolution, with electrospray ionization in the positive mode. Accuracy and precision were assessed over three independent validation batches. Extraction recoveries were more than 98% and were consistent across the analytical range. Both analytes in CSF exhibited non-specific adsorption to polypropylene tubes. The method was used to analyse cerebrospinal fluid samples from patients with pulmonary tuberculosis in an exploratory pharmacokinetic study.

Use of cerebrospinal fluid CXCL13 concentration for diagnosis and monitoring of neurosyphilis: a three-case report

Introduction: Previous retrospective studies have demonstrated that the concentration of chemokine ligand CXCL13 in cerebrospinal fluid (CSF-CXCL13) is a promising biomarker in the diagnosis of neurosyphilis and, additionally, in the monitoring of therapeutic efficacy. Objective: To describe three cases of patients with neurosyphilis (NS) treated at Hospital Universitário Gaffrée e Guinle, in Rio de Janeiro, Brazil, with suspected active syphilis with neurological symptoms. Case report: Three patients from Rio de Janeiro, Brazil, were investigated for symptomatic NS. The concentration of CSF-CXCL13 was prospectively performed by enzyme-linked immunosorbent assay (ELISA) in all participants at baseline and in follow-up visits at 3 months after therapy. CSF-CXCL13 concentrations were significantly higher in all three patients with established NS. The CSF-CXCL13 concentrations decreased after 3 months of therapy compared to baseline in all cases reported. The added high concentration of CSF-CXCL13 plus CSF-TPHA reactivity above 1:40 titer agreed with the diagnosis of NS in 100% of the cases. Conclusion: In this case series, we present three cases of NS diagnosed using CXCL13 in CSF as a complementary test. These case series suggest that the clinical use of CSF-CXCL13 is useful as a supplementary biomarker for NS and for monitoring the effectiveness of NS therapy, especially in patients with nonreactive CSF-VDRL, excluding other neurologic diseases

Neurodegeneration Markers in the Cerebrospinal Fluid of 100 Patients with Schizophrenia Spectrum Disorder.

BACKGROUND: Schizophrenia spectrum disorders (SSD) can be associated with neurodegenerative processes causing disruption of neuronal, synaptic, or axonal integrity. Some previous studies have reported alterations of neurodegenerative markers (such as amyloid beta [Aß], tau, or neurofilaments) in patients with SSD. However, the current state of research remains inconclusive. Therefore, the rationale of this study was to investigate established neurodegenerative markers in the cerebrospinal fluid (CSF) of a large group of patients with SSD. STUDY DESIGN: Measurements of Aß1-40, Aß1-42, phospho- and total-tau in addition to neurofilament light (NFL), medium (NFM), and heavy (NFH) chains were performed in the CSF of 100 patients with SSD (60 F, 40 M; age 33.7 ± 12.0) and 39 controls with idiopathic intracranial hypertension (33 F, 6 M; age 34.6 ± 12.0) using enzyme-linked immunoassays. STUDY RESULTS: The NFM levels were significantly increased in SSD patients (P = .009), whereas phospho-tau levels were lower in comparison to the control group (P = .018). No other significant differences in total-tau, beta-amyloid-quotient (Aß1-42/Aß1-40), NFL, and NFH were identified. CONCLUSIONS: The findings argue against a general tauopathy or amyloid pathology in patients with SSD. However, high levels of NFM, which has been linked to regulatory functions in dopaminergic neurotransmission, were associated with SSD. Therefore, NFM could be a promising candidate for further research on SSD.

Meningitis por Listeria: administración de gentamicina intraventricular y monitorización de concentraciones en líquido cefalorraquídeo / Listeria meningitis: administration of intraventricular gentamicin and monitoring of concentrations in cerebrospinal fluid

La Listeria continúa siendo una posible etiología de meningitis bacteriana en nuestro medio, siendo causa más frecuente en neonatos, ancianos o pacientes inmunodeprimidos. Debido a la gravedad y la mortalidad asociada, resulta de gran interés disponer de nuevas herramientas que permitan un manejo clínico y farmacológico más eficaz.Presentamos un caso de meningitis por Listeria que ingresa en la Unidad de Cuidados Intensivos. Dada la escasa penetración de la gentamicina en el sistema nervioso central y siendo ésta uno de los tratamientos de elección en las guías clínicas de referencia, se decide la administración de gentamicina intraventricular llevando a cabo una monitorización de concentraciones de gentamicina en líquido cefalorraquídeo (LCR).Debido a la alta variabilidad farmacocinética del paciente crítico, la monitorización de concentraciones en LCR de gentamicina tras su administración intraventricular puede resultar de gran utilidad para asegurar el alcance de concentraciones de fármaco que permitan una mayor eficacia del tratamiento. (AU)

Listeria is currently a possible etiology of bacterial meningitis in our society, being one more frequent cause in neonates, elderly or immunosuppressed patients. Due to the severity and mortality associated, it is therefore very useful to have new tools that allow a more effective clinical and pharmacological management.We present a case of Listeria meningitis admitted to the Intensive Care Unit. Given the low penetration of gentamicin into the central nervous system and being one of the treatments of choice in the clinical reference guidelines, the administration of intraventricular gentamicin was decided by monitoring the concentrations of gentamicin in cerebrospinal fluid (CSF).Due to the high pharmacokinetic variability of the critically ill patient, monitoring CSF concentrations of gentamicin after intraventricular administration can be very useful to ensure the achievement of drug concentrations that allow greater treatment efficacy. (AU)

SOBA: Development and testing of a soluble oligomer binding assay for detection of amyloidogenic toxic oligomers.

The formation of toxic Amyloid ß-peptide (Aß) oligomers is one of the earliest events in the molecular pathology of Alzheimer's Disease (AD). These oligomers lead to a variety of downstream effects, including impaired neuronal signaling, neuroinflammation, tau phosphorylation, and neurodegeneration, and it is estimated that these events begin 10 to 20 y before the presentation of symptoms. Toxic Aß oligomers contain a nonstandard protein structure, termed α-sheet, and designed α-sheet peptides target this main-chain structure in toxic oligomers independent of sequence. Here we show that a designed α-sheet peptide inhibits the deleterious effects on neuronal signaling and also serves as a capture agent in our soluble oligomer binding assay (SOBA). Pre-incubated synthetic α-sheet-containing Aß oligomers produce strong SOBA signals, while monomeric and ß-sheet protofibrillar Aß do not. α-sheet containing oligomers were also present in cerebrospinal fluid (CSF) from an AD patient versus a noncognitively impaired control. For the detection of toxic oligomers in plasma, we developed a plate coating to increase the density of the capture peptide. The proof of concept was achieved by testing 379 banked human plasma samples. SOBA detected Aß oligomers in patients on the AD continuum, including controls who later progressed to mild cognitive impairment. In addition, SOBA discriminated AD from other forms of dementia, yielding sensitivity and specificity of 99% relative to clinical and neuropathological diagnoses. To explore the broader potential of SOBA, we adapted the assay for a-synuclein oligomers and confirmed their presence in CSF from patients with Parkinson's disease and Lewy body dementia.

SWATH Mass Spectrometry-Based CSF Proteome Profile of GBA-Linked Parkinson's Disease Patients.

ß-glucocerebrosidase (GBA)-associated mutations are a significant risk factor for Parkinson's disease (PD) that aggravate the disease pathology by upregulating the deposition of α-Synuclein (α-Syn). The resultant clinical profile varies for PD patients without GBA mutations. The current study aimed to identify the proteomic targets involved in the pathogenic pathways leading to the differential clinical presentation of GBA-associated PD. CSF samples (n = 32) were obtained from PD patients with GBA mutations (n = 22), PD patients without GBA mutations (n = 7), and healthy controls that were carriers of GBA mutations (n = 3). All samples were subjected to in-gel tryptic digestion followed by the construction of the spectral library and quantitative SWATH-based analysis. CSF α-Syn levels were reduced in both PDIdiopathic and PDGBA cases. Our SWATH-based mass spectrometric analysis detected 363 proteins involved in immune response, stress response, and cell signaling in various groups. Intergroup analysis showed that 52 proteins were significantly up- or downregulated in various groups. Of these 52 targets, 20 proteins were significantly altered in PDGBA cases only while 2 showed different levels in PDIdiopathic patients. Our results show that the levels of several pathologically relevant proteins, including Contactin-1, Selenium-binding protein 1, Adhesion G Protein-Coupled Receptor, and Apolipoprotein E are significantly different among the sporadic and genetic variants of PD and hint at aggravated synaptic damage, oxidative stress, neuronal loss, and aggregation of α-Syn in PDGBA cases.

Cerebrospinal Fluid and Blood Biomarkers of Neuroinflammation and Blood-Brain Barrier in Psychotic Disorders and Individually Matched Healthy Controls.

BACKGROUND AND HYPOTHESIS: Neuroinflammation and blood-brain barrier (BBB) dysfunction have been observed in patients with psychotic disorders. However, previous studies have mainly focused on selected patients and broad screenings of cerebrospinal fluid (CSF) of patients with recent onset psychosis compared to healthy controls are lacking. STUDY DESIGN: We included 104 patients with recent onset psychotic disorder and 104 individually matched healthy controls. CSF and blood were analyzed for readily available markers assessing neuroinflammation and BBB dysfunction. Primary outcomes were CSF white blood cell count (WBC), total protein, IgG Index, and CSF/serum albumin ratio. Secondary outcomes included additional markers of inflammation and BBB, and analyses of association with clinical variables. STUDY RESULTS: CSF/serum albumin ratio (Relative Mean Difference (MD): 1.11; 95%CI: 1.00-1.23; P = .044) and CSF/serum IgG ratio (MD: 1.17; 95%CI: 1.01-1.36; P = .036) was increased in patients compared to controls. A higher number of patients than controls had CSF WBC >3 cells/µl (seven vs. one, OR: 7.73, 95%CI: 1.33-146.49, P = .020), while WBC>5 cells/µl was found in two patients (1.9%) and no controls. Inpatients had higher serum WBC and neutrophil/lymphocyte ratio (all p-values for effect heterogeneity < .011). Mean CSF WBC (MD: 1.10; 95%CI: 0.97-1.26), protein (MD: 1.06; 95%CI: 0.98-1.15) and IgG index (MD: 1.05; 95%CI: 0.96-1.15) were not significantly elevated. CONCLUSIONS: When comparing a broad group of patients with psychotic disorders with healthy controls, patients had increased BBB permeability, more patients had high CSF WBC levels, and inpatients had increased peripheral inflammation, consistent with the hypothesis of a subgroup of patients with increased activation of the immune system.

Impact of Cerebrospinal Fluid Sample Handling on Cytokine Detection Results.

OBJECTIVE: To investigate the impact of different treatment methods on cerebrospinal fluid (CSF) cytokine detection. METHODS: CSF samples were collected from 25 patients. The levels of IL-6, IL-10, IFN-γ, and IL-2 were measured after CSF was stored at room temperature (25°C) or 4°C for 6, 12, and 24 hrs. The CSF was frozen at -80°C, thawed at room temperature for 1 hr every 8 hrs and then frozen. This process was repeated three times in a row, and then cytokine levels in CSF were detected again. RESULTS: The four cytokines were stable when the CSF was kept at room temperature for 6 hrs. After 12 hrs of storage, the levels of the four cytokines decreased, and the changes in IL-6 and IL-10 levels were statistically significant. After 24 hrs of storage, the levels of the four cytokines were further reduced, and the changes were statistically significant. Cytokines were stable when CSF was stored at 4°C, and only IL-10 exhibited statistically significant changes when stored for 24 hrs. IL-6, IL-10 IFN-γ, and IL-2 were stable in CSF samples after three freeze-thaw cycles. CONCLUSION: The stability of CSF cytokines is poor after storage at room temperature and good after storage at 4°C. Therefore, cytokine detection should be carried out after CSF collection as often as possible. If the detection cannot be done quickly enough, the specimens should be stored in cold storage for no more than 24 hrs.

Gene alternation of cerebrospinal fluid in patients with leptomeningeal metastases of lung adenocarcinoma using next-generation sequencing.

BACKGROUND: Epidermal growth factor receptor tyrosine kinase inhibitors (EGFR-TKIs) provide a better prognosis in EGFR-mutant non-small cell lung cancer (NSCLC). Nevertheless, the outcome of leptomeningeal metastasis (LM) remains poor. In addition, due to limited access to intracranial tumour tissue, gene alterations associated with leptomeningeal metastasis from lung adenocarcinoma (LM-LUAD) are unclear. METHODS: Forty-five patients with LM-LUAD from May 2019 to June 2021 in Guangdong Sanjiu Brain Hospital were enrolled in this study. Seventy-five percent (34/45) of patients with LM harbored EGFR mutations, and patients with progressive disease (PD) of LM had 3rd-generation EGFR-TKI therapy and were defined as Cohort 1; those without 3rd-generation EGFR-TKI therapy were defined as Cohort 2. Next-generation targeted panel sequencing (NGS) was performed in each cerebrospinal fluid (CSF) sample of the two cohorts, and 9/45 LM-LUAD patients had matched plasma (PLA). RESULTS: The common gene alterations discovered in the CSF of LM-LUAD were EGFR mutation (34/45, 75%), TP53 (25/45, 56%), CDKN2A (9/45, 20%), ALK (7/45, 16%), CTNNB1 (6/45, 13%), MET (5/45, 11%), APC (4/45, 9%), FGF4 (4/45, 9%), FGF3 (4/45, 9%), ERBB2 (4/45, 9%), and PIK3CG (4/45, 9%). Cooccurring mutations of TP53 and EGFR were found in 49% (22/45) of patients and correlated with poor prognosis. CDKN2A was identified in 20% (9/45) of patients and presented slightly shorter overall survival (OS) than those without (7.1 versus 8.8 months, p = 0.2). Cohort 1 had more genes associated with poor prognosis, consisting of CDK4, CDKN2A, PIK3CG, or PIK3CA, and YES1 and MET were more likely to be detected in cohort 2. The alteration of EGFR was comparable between CSF and matched PLA. Incidences of gene alterations such as CDK4, CDKN2A, MET, SOX2, JAK2, BRAF, and PIK3CG were more likely to be identified in CSF. All mutant allele frequencies (MAF) were much higher in CSF than in matched PLA. CONCLUSIONS: CSF could be a potential candidate for the genetic profiling of LM-LUAD, demonstrating the genetic characteristics of LM in EGFR-mutated lung adenocarcinoma on diverse EGFR-TKI therapies.

Electrochemical biosensing of circulating microRNA-21 in cerebrospinal fluid of medulloblastoma patients through target-induced redox signal amplification.

Monitoring of cerebrospinal fluid (CSF) microRNAs (miRs) offers a promising option for the diagnosis and management of patients with central nervous system tumors. However, the sensitive detection of miRs in clinical CSF samples has been hindered by the ultra-low abundance of target miRs. Here, we report an electrochemical biosensor for the highly sensitive label-free detection of CSF miR-21 relying on target-induced redox signal amplification (eTIRSA). The biosensor was developed by covalently assembling the capture stands partially complementary to miR-21 on the gold nanoparticle-coated glassy carbon electrode. In the presence of miR-21, the short capture stand hybridized with the partial bases of miR-21, allowing the rest sequence of the target molecule to further bind with a long guanine-rich sequence which could specifically adsorb a number of methylene blue indicators, thus generating an amplified electrochemical redox signal, typically at a working potential of - 0.19 V (vs. SCE). The response of the surface-bound methylene blue indicators was positively correlated to the concentration of miR-21, providing a dynamic range of 0.5-80 pM and a limit of detection down to 56 fM. Moreover, the eTIRSA biosensor had high specificity with single-base resolution and exhibited good performance for label-free quantification of miR-21 in medulloblastoma cell extracts and clinical CSF samples and for accurate discrimination of medulloblastoma against non-cancer controls, indicating its potential application in CSF miR-based liquid biopsy of brain cancers.

Central Nervous System Stimulants Limit Caffeine Transport at the Blood-Cerebrospinal Fluid Barrier.

Caffeine, a common ingredient in energy drinks, crosses the blood-brain barrier easily, but the kinetics of caffeine across the blood-cerebrospinal fluid barrier (BCSFB) has not been investigated. Therefore, 127 autopsy cases (Group A, 30 patients, stimulant-detected group; and Group B, 97 patients, no stimulant detected group) were examined. In addition, a BCSFB model was constructed using human vascular endothelial cells and human choroid plexus epithelial cells separated by a filter, and the kinetics of caffeine in the BCSFB and the effects of 4-aminopyridine (4-AP), a neuroexcitatory agent, were studied. Caffeine concentrations in right heart blood (Rs) and cerebrospinal fluid (CSF) were compared in the autopsy cases: caffeine concentrations were higher in Rs than CSF in Group A compared to Group B. In the BCSFB model, caffeine and 4-AP were added to the upper layer, and the concentration in the lower layer of choroid plexus epithelial cells was measured. The CSF caffeine concentration was suppressed, depending on the 4-AP concentration. Histomorphological examination suggested that choroid plexus epithelial cells were involved in inhibiting the efflux of caffeine to the CSF. Thus, the simultaneous presence of stimulants and caffeine inhibits caffeine transfer across the BCSFB.

Characterization of Oxygen Levels in an Uninfected and Infected Human Blood-Cerebrospinal-Fluid-Barrier Model.

The host-pathogen interaction during meningitis can be investigated with blood-cerebrospinal-fluid-barrier (BCSFB) cell culture models. They are commonly handled under atmospheric oxygen conditions (19-21% O2), although the physiological oxygen conditions are significantly lower in cerebrospinal fluid (CSF) (7-8% O2). We aimed to characterize oxygen levels in a Streptococcus (S.) suis-infected BCSFB model with transmigrating neutrophils. A BCSFB model with human choroid plexus epithelial cells growing on transwell-filters was used. The upper "blood"-compartment was infected and blood-derived neutrophils were added. S. suis and neutrophils transmigrated through the BCSFB into the "CSF"-compartment. Here, oxygen and pH values were determined with the non-invasive SensorDish® reader. Slight orbital shaking improved the luminescence-based measurement technique for detecting free oxygen. In the non-infected BCSFB model, an oxygen value of 7% O2 was determined. However, with S. suis and transmigrating neutrophils, the oxygen value significantly decreased to 2% O2. The pH level decreased slightly in all groups. In conclusion, we characterized oxygen levels in the BCSFB model and demonstrated the oxygen consumption by cells and bacteria. Oxygen values in the non-infected BCSFB model are comparable to in vivo values determined in pigs in the CSF. Infection and transmigrating neutrophils decrease the oxygen value to lower values.

Quantitative proteomic analysis of cerebrospinal fluid of women newly diagnosed with multiple sclerosis.

PURPOSE: The lack of reliable diagnostic and/or prognostic biomarkers for multiple sclerosis (MS) is the major obstacle to timely and accurate patient diagnosis in MS patients. To identify new proteins associated with MS we performed a detailed proteomic analysis of cerebrospinal fluid (CSF) of patients newly diagnosed with relapsing-remitting MS (RRMS) and healthy controls. MATERIAL: Reflecting significantly higher prevalence of MS in women we included only women patients and controls in the study. To eliminate a potential effect of therapy on the CSF composition, only the therapy-naïve patients were included. METHODS: Pooled CSF samples were processed in a technical duplicate, and labeled with stable-isotope coded TMT tags. To maximize the proteome coverage, peptide fractionation using 2D-LC preceded mass analysis using Orbitrap Fusion Tribrid Mass Spectrometer. Differential concentration of selected identified proteins between patients and controls was verified using specific antibodies. RESULTS: Of the identified 900 CSF proteins, we found 69 proteins to be differentially abundant between patients and controls. In addition to several proteins identified as differentially abundant in MS patients previously, we observed several linked to MS for the first time, namely eosinophil-derived neurotoxin and Nogo receptor. CONCLUSIONS: Our data confirm differential abundance of several previously proposed protein markers, and provide indirect support for involvement of copper-iron disbalance in MS. Most importantly, we identified two new differentially abundant CSF proteins that seem to be directly connected with myelin loss and axonal damage via TLR2 signaling and Nogo-receptor pathway in women newly diagnosed with RRMS.

Biochemical profile of human infant cerebrospinal fluid in intraventricular hemorrhage and post-hemorrhagic hydrocephalus of prematurity.

BACKGROUND: Intraventricular hemorrhage (IVH) and post-hemorrhagic hydrocephalus (PHH) have a complex pathophysiology involving inflammatory response, ventricular zone and cell-cell junction disruption, and choroid-plexus (ChP) hypersecretion. Increased cerebrospinal fluid (CSF) cytokines, extracellular matrix proteins, and blood metabolites have been noted in IVH/PHH, but osmolality and electrolyte disturbances have not been evaluated in human infants with these conditions. We hypothesized that CSF total protein, osmolality, electrolytes, and immune cells increase in PHH. METHODS: CSF samples were obtained from lumbar punctures of control infants and infants with IVH prior to the development of PHH and any neurosurgical intervention. Osmolality, total protein, and electrolytes were measured in 52 infants (18 controls, 10 low grade (LG) IVH, 13 high grade (HG) IVH, and 11 PHH). Serum electrolyte concentrations, and CSF and serum cell counts within 1-day of clinical sampling were obtained from clinical charts. Frontal occipital horn ratio (FOR) was measured for estimating the degree of ventriculomegaly. Dunn or Tukey's post-test ANOVA analysis were used for pair-wise comparisons. RESULTS: CSF osmolality, sodium, potassium, and chloride were elevated in PHH compared to control (p = 0.012 - < 0.0001), LGIVH (p = 0.023 - < 0.0001), and HGIVH (p = 0.015 - 0.0003), while magnesium and calcium levels were higher compared to control (p = 0.031) and LGIVH (p = 0.041). CSF total protein was higher in both HGIVH and PHH compared to control (p = 0.0009 and 0.0006 respectively) and LGIVH (p = 0.034 and 0.028 respectively). These differences were not reflected in serum electrolyte concentrations nor calculated osmolality across the groups. However, quantitatively, CSF sodium and chloride contributed 86% of CSF osmolality change between control and PHH; and CSF osmolality positively correlated with CSF sodium (r, p = 0.55,0.0015), potassium (r, p = 0.51,0.0041), chloride (r, p = 0.60,0.0004), but not total protein across the entire patient cohort. CSF total cells (p = 0.012), total nucleated cells (p = 0.0005), and percent monocyte (p = 0.016) were elevated in PHH compared to control. Serum white blood cell count increased in PHH compared to control (p = 0.042) but there were no differences in serum cell differential across groups. CSF total nucleated cells also positively correlated with CSF osmolality, sodium, potassium, and total protein (p = 0.025 - 0.0008) in the whole cohort. CONCLUSIONS: CSF osmolality increased in PHH, largely driven by electrolyte changes rather than protein levels. However, serum electrolytes levels were unchanged across groups. CSF osmolality and electrolyte changes were correlated with CSF total nucleated cells which were also increased in PHH, further suggesting PHH is a neuro-inflammatory condition.

"The quantitative determination of indolic microbial tryptophan metabolites in human and rodent samples: A systematic review".

Concentrations reported for indolic microbial metabolites of tryptophan in human and rodent brain, cerebrospinal fluid, plasma, saliva and feces were compiled and discussed. A systematic review of the literature was accomplished by key word searches of Pubmed, Google Scholar and the Human Metabolome Data Base (HMDB), and by searching bibliographies of identified publications including prior reviews. The review was prompted by the increasing appreciation of the physiological importance of the indolic compounds in human health and disease. The compounds included were indoleacetic acid (IAA), indole propionic acid (IPA), indoleacrylic acid (IACR), indolelactic acid (ILA) indolepyruvic acid (IPY), indoleacetaldehyde (IAALD), indolealdehyde (IALD), tryptamine (TAM), indole (IND) and skatole (SKT). The undertaking aimed to vet and compare existing reports, to resolve apparent discrepancies, to draw biological inferences from the consideration of multiple analytes across sample types, to survey the analytical methodologies used, and to point out areas in need of greater attention.