Association of Lumbar Puncture With Spinal Hematoma in Patients With and Without Coagulopathy

IMPORTANCE

Coagulopathy may deter physicians from performing a lumbar puncture.

OBJECTIVE

To determine the risk of spinal hematoma after lumbar puncture in patients with and without coagulopathy.

DESIGN, SETTING, AND PARTICIPANTS

Danish nationwide, population-based cohort study using medical registries to identify persons who underwent lumbar puncture and had cerebrospinal fluid analysis (January 1, 2008-December 31, 2018; followed up through October 30, 2019). Coagulopathy was defined as platelets lower than 150 × 109/L, international normalized ratio (INR) greater than 1.4, or activated partial thromboplastin time (APTT) longer than 39 seconds.

EXPOSURES

Coagulopathy at the time of lumbar puncture.

MAIN OUTCOMES AND MEASURES

Thirty-day risk of spinal hematoma. Risks were provided as numbers and percentages with 95% CIs. Secondary analyses included risks of traumatic lumbar puncture (>300 × 106 erythrocytes/L after excluding patients diagnosed with subarachnoid hemorrhage). Adjusted hazard rate ratios (HRs) were computed using Cox regression models.

RESULTS

A total of 83 711 individual lumbar punctures were identified among 64 730 persons (51% female; median age, 43 years [interquartile range, 22-62 years]) at the time of the procedure. Thrombocytopenia was present in 7875 patients (9%), high INR levels in 1393 (2%), and prolonged APTT in 2604 (3%). Follow-up was complete for more than 99% of the study participants. Overall, spinal hematoma occurred within 30 days for 99 of 49 526 patients (0.20%; 95% CI, 0.16%-0.24%) without coagulopathy vs 24 of 10 371 patients (0.23%; 95% CI, 0.15%-0.34%) with coagulopathy. Independent risk factors for spinal hematoma were male sex (adjusted hazard ratio [HR], 1.72; 95% CI, 1.15-2.56), those aged 41 through 60 years (adjusted HR, 1.96; 95% CI, 1.01-3.81) and those aged 61 through 80 years (adjusted HR, 2.20; 95% CI, 1.12-4.33). Risks did not increase significantly according to overall severity of coagulopathy, in subgroup analyses of severity of coagulopathy by pediatric specialty or medical indication (infection, neurological condition, and hematological malignancy), nor by cumulative number of procedures. Traumatic lumbar punctures occurred more frequently among patients with INR levels of 1.5 to 2.0 (36.8%; 95% CI, 33.3%-40.4%), 2.1 to 2.5 (43.7%; 95% CI, 35.8%-51.8%), and 2.6 to 3.0 (41.9% 95% CI 30.5-53.9) vs those with normal INR (28.2%; 95% CI, 27.7%-28.75%). Traumatic spinal tap occurred more often in patients with an APTT of 40 to 60 seconds (26.3%; 95% CI, 24.2%-28.5%) vs those with normal APTT (21.3%; 95% CI, 20.6%-21.9%) yielding a risk difference of 5.1% (95% CI, 2.9%-7.2%).

CONCLUSIONS AND RELEVANCE

In this Danish cohort study, risk of spinal hematoma following lumbar puncture was 0.20% among patients without coagulopathy and 0.23% among those with coagulopathy. Although these findings may inform decision-making about lumbar puncture by describing rates in this sample, the observed rates may reflect bias due to physicians selecting relatively low-risk patients for lumbar puncture.

Association of Cigarette Smoking With Cerebrospinal Fluid Biomarkers of Neurodegeneration, Neuroinflammation, and Oxidation

IMPORTANCE

Cigarette smoking has been associated with risk of neurodegenerative disorders, such as Alzheimer disease. The association between smoking and biomarkers of changes in human cerebrospinal fluid (CSF) is not fully understood.

OBJECTIVE

To investigate the association of cigarette smoking with CSF biomarkers of neurodegeneration, neuroinflammation, oxidation, and neuroprotection.

DESIGN, SETTING, AND PARTICIPANTS

In this case-control study of 191 adult men in China, biomarkers in the CSF of participants with and without significant cigarette exposure were examined. Participants who did not smoke and had no history of substance use disorder or dependence were assigned to the nonsmoking group. The active smoking group included participants who consumed at least 10 cigarettes per day for 1 year. Five-milliliter samples of CSF were obtained from routine lumbar puncture conducted before anterior cruciate ligament reconstruction surgery. Data collection took place from September 2014 to January 2016, and analysis took place from January to February 2016.

EXPOSURES

Cigarette smoking.

MAIN OUTCOMES AND MEASURES

CSF levels of β-amyloid 42 (Aβ42), which has diagnostic specificity for Alzheimer disease, tumor necrosis factor alpha (TNFα), brain-derived neurotrophic factor (BDNF), total superoxide dismutase (SOD), and nitric oxide synthase (NOS) were measured. Sociodemographic data and history of smoking were obtained.

RESULTS

Of 191 participants, 87 (45.5%) were included in the active smoking group and 104 (54.4%) in the nonsmoking group. Compared with the active smoking group, the nonsmoking group was younger (mean [SD] age, 34.4 [10.5] years vs 29.6 [9.5] years; P = .01), had more education (mean [SD] duration of education, 11.9 [3.1] years vs 13.2 [2.6] years; P = .001), and had lower body mass index (mean [SD], 25.9 [3.6] vs 24.9 [4.0]; P = .005). Comparing the nonsmoking group with the smoking group, mean (SD) CSF levels of Aβ42 (38.0 [25.9] pg/mL vs 52.8 [16.5] pg/mL; P < .001) and TNFα (23.0 [2.5] pg/mL vs 28.0 [2.0] pg/mL; P < .001) were significantly lower, while BDNF (23.1 [3.9] pg/mL vs 13.8 [2.7] pg/mL; P < .001), total SOD (15.7 [2.6] U/L vs 13.9 [2.4] U/L; P < .001), total NOS (28.3 [7.2] U/L vs 14.7 [5.6] U/L; P < .001), inducible NOS (16.0 [5.4] U/L vs 10.3 [2.7] U/L; P < .001), and constitutive NOS (12.4 [6.9] U/mL vs 4.4 [3.9] U/mL) were higher. In addition, in participants in the smoking group who were aged 40 years or older, total SOD levels were negatively correlated with Aβ42 levels (r = -0.57; P = .02). In those who smoked at least 20 cigarettes per day, TNFα levels were positively correlated with Aβ42 levels (r = 0.51; P = .006). The association of TNFα with Aβ42 production was stronger than that of total SOD with Aβ42 production (z = -4.38; P < .001).

CONCLUSIONS AND RELEVANCE

This case-control study found that cigarette smoking was associated with at-risk biomarkers for Alzheimer disease, as indicated by higher Aβ42 levels, excessive oxidative stress, neuroinflammation, and impaired neuroprotection found in the CSF of participants in the active smoking group.

ABCA1/ApoE/HDL Signaling Pathway Facilitates Myelination and Oligodendrogenesis after Stroke

ATP-binding cassette transporter A1 (ABCA1) plays an important role in the regulation of apolipoprotein E (ApoE) and the biogenesis of high-density lipoprotein (HDL) cholesterol in the mammalian brain. Cholesterol is a major source for myelination. Here, we investigate whether ABCA1/ApoE/HDL contribute to myelin repair and oligodendrogenesis in the ischemic brain after stroke. Specific brain ABCA1-deficient (ABCA1^-B/-B) and ABCA1-floxed (ABCA1^fl/fl) control mice were subjected to permanent distal middle-cerebral-artery occlusion (dMCAo) and were intracerebrally administered (1) artificial mouse cerebrospinal fluid (CSF) as vehicle control, (2) human plasma HDL3, and (3) recombined human ApoE2 starting 24 h after dMCAo for 14 days. All stroke mice were sacrificed 21 days after dMCAo. The ABCA1^-B/-B–dMCAo mice exhibit significantly reduced myelination and oligodendrogenesis in the ischemic brain as well as decreased functional outcome 21 days after stroke compared with ABCA1^fl/fl mice; administration of human ApoE2 or HDL3 in the ischemic brain significantly attenuates the deficits in myelination and oligodendrogenesis in ABCA1^-B/-B–dMCAo mice ( p < 0.05, n = 9/group). In vitro, ABCA1^-B/-B reduces ApoE expression and decreases primary oligodendrocyte progenitor cell (OPC) migration and oligodendrocyte maturation; HDL3 and ApoE2 treatment significantly reverses ABCA1^-B/-B-induced reduction in OPC migration and oligodendrocyte maturation. Our data indicate that the ABCA1/ApoE/HDL signaling pathway contributes to myelination and oligodendrogenesis in the ischemic brain after stroke.

Implantable Sensor for Detecting Changes in the Loss Tangent of Cerebrospinal Fluid

The increasing utilization of cerebrospinal fluid (CSF) in early detection of Alzheimer's disease (AD) is attributed to the change of Amyloid- β proteins. Since, the brain is suspended in CSF, changes of Amyloid- β proteins in CSF reflect a pathophysiological variation of the brain due to AD. However, the correlation between Amyloid- β proteins and the dielectric properties (DPs) of CSF is still an open question. This paper reports the characterized DPs of CSF collected from canines using lumbar punctures. The CSF samples from canines show a strong correlation with respect to human in terms of the loss tangent, which indicates suitability of using canines as translational primates. Amyloid- β [ Aβ(1-40) and Aβ(1-42)] proteins associated with AD were added to CSF samples in order to emulate AD condition. The results of emulated AD condition suggest a decrease in the relative permittivity and increase in the loss tangent. To detect changes in the loss tangent of CSF, which combines both relative permittivity and conductivity, a developed sensor is proposed. The designed sensor consists of a voltage controlled oscillator (VCO) and implantable antenna, which exhibits a wideband and low quality factor to be stable with respect to changes in the loss tangent of CSF. The measurements of the received power levels from the sensor in different liquid-based phantoms having different loss tangent values were used to correlate changes in the loss tangent. The developed correlation model is able to predict the loss tangent based on the received power level, which can be used to detect changes in the loss tangent of CSF due to AD. Consequently, this approach could be used as an early diagnosis of AD.

Large-scale proteomic analysis of Alzheimer's disease brain and cerebrospinal fluid reveals early changes in energy metabolism associated with microglia and astrocyte activation

Our understanding of Alzheimer's disease (AD) pathophysiology remains incomplete. Here we used quantitative mass spectrometry and coexpression network analysis to conduct the largest proteomic study thus far on AD. A protein network module linked to sugar metabolism emerged as one of the modules most significantly associated with AD pathology and cognitive impairment. This module was enriched in AD genetic risk factors and in microglia and astrocyte protein markers associated with an anti-inflammatory state, suggesting that the biological functions it represents serve a protective role in AD. Proteins from this module were elevated in cerebrospinal fluid in early stages of the disease. In this study of >2,000 brains and nearly 400 cerebrospinal fluid samples by quantitative proteomics, we identify proteins and biological processes in AD brains that may serve as therapeutic targets and fluid biomarkers for the disease.

Mass spectrometry-based proteomic techniques to identify cerebrospinal fluid biomarkers for diagnosing suspected central nervous system infections. A systematic review

OBJECTIVES

Central nervous system (CNS) infections account for considerable death and disability every year. An urgent research priority is scaling up diagnostic capacity, and introduction of point-of-care tests. We set out to assess current evidence for the application of mass spectrometry (MS) peptide sequencing in identification of diagnostic biomarkers for CNS infections.

METHODS

We performed a systematic review (PROSPEROCRD42018104257) using PRISMA guidelines on use of MS to identify cerebrospinal fluid (CSF) biomarkers for diagnosing CNS infections. We searched PubMed, Embase, Web of Science, and Cochrane for articles published from 1 January 2000 to 1 February 2019, and contacted experts. Inclusion criteria involved primary research except case reports, on the diagnosis of infectious diseases except HIV, applying MS to human CSF samples, and English language.

RESULTS

4,620 papers were identified, of which 11 were included, largely confined to pre-clinical biomarker discovery, and eight (73%) published in the last five years. 6 studies performed further work termed verification or validation. In 2 of these studies, it was possible to extract data on sensitivity and specificity of the biomarkers detected by ELISA, ranging from 89-94% and 58-92% respectively.

CONCLUSIONS

The findings demonstrate feasibility and potential of the methods in a variety of infectious diseases, but emphasise the need for strong interdisciplinary collaborations to ensure appropriate study design and biomarker validation.

The microbiota regulate neuronal function and fear extinction learning

Multicellular organisms have co-evolved with complex consortia of viruses, bacteria, fungi and parasites, collectively referred to as the microbiota1. In mammals, changes in the composition of the microbiota can influence many physiologic processes (including development, metabolism and immune cell function) and are associated with susceptibility to multiple diseases2. Alterations in the microbiota can also modulate host behaviours-such as social activity, stress, and anxiety-related responses-that are linked to diverse neuropsychiatric disorders3. However, the mechanisms by which the microbiota influence neuronal activity and host behaviour remain poorly defined. Here we show that manipulation of the microbiota in antibiotic-treated or germ-free adult mice results in significant deficits in fear extinction learning. Single-nucleus RNA sequencing of the medial prefrontal cortex of the brain revealed significant alterations in gene expression in excitatory neurons, glia and other cell types. Transcranial two-photon imaging showed that deficits in extinction learning after manipulation of the microbiota in adult mice were associated with defective learning-related remodelling of postsynaptic dendritic spines and reduced activity in cue-encoding neurons in the medial prefrontal cortex. In addition, selective re-establishment of the microbiota revealed a limited neonatal developmental window in which microbiota-derived signals can restore normal extinction learning in adulthood. Finally, unbiased metabolomic analysis identified four metabolites that were significantly downregulated in germ-free mice and have been reported to be related to neuropsychiatric disorders in humans and mouse models, suggesting that microbiota-derived compounds may directly affect brain function and behaviour. Together, these data indicate that fear extinction learning requires microbiota-derived signals both during early postnatal neurodevelopment and in adult mice, with implications for our understanding of how diet, infection, and lifestyle influence brain health and subsequent susceptibility to neuropsychiatric disorders.

Cavitation threshold evaluation of porcine cerebrospinal fluid using a Polymeric Split Hopkinson Pressure Bar-Confinement chamber apparatus

Studies investigating mild Traumatic Brain Injury (mTBI) in the military population using experimental head surrogates and Finite Element (FE) head models have demonstrated the existence of transient negative pressures occurring within the head at the contrecoup location to the blast wave impingement. It has been hypothesized that this negative pressure may cause cavitation of cerebrospinal fluid (CSF) and possibly lead to brain tissue damage from cavitation bubble collapse. The cavitation pressure threshold of human CSF is presently unknown, although existing FE studies in the literature have assumed a value of -100 kPa. In the present study, the cavitation threshold of degassed porcine CSF at body temperature (37 °C) was measured using a unique modified Polymeric Split Hopkinson Pressure Bar apparatus, and compared to thresholds of distilled water at various conditions. The loading pulse generated in the apparatus was comparable to experimentally measured pressures resulting from blast exposure, and those predicted by an FE model. The occurrence of cavitation was identified using high-speed imaging and the corresponding pressures were determined using a computational model of the apparatus that was previously developed and validated. The probability of cavitation was calculated (ISO/TS, 18506) from forty-one experimental tests on porcine CSF, representing an upper bound for in vivo CSF. The 50% probability of cavitation for CSF (-0.467 MPa ± 7%) was lower than that of distilled water (-1.37 MPa ± 16%) under the same conditions. The lesser threshold of CSF could be related to the constituents such as blood cells and proteins. The results of this study can be used to inform FE head models subjected to blast exposure and improve prediction of the potential for CSF cavitation and response of brain tissue.

Assessment of Diagnostic Yield of Nonculture Infection Testing on Cerebrospinal Fluid in Immune-Competent Children

IMPORTANCE

Nonculture infection tests of cerebrospinal fluid (CSF) samples using polymerase chain reaction and antigen or antibody assays are frequently ordered on lumbar puncture specimens concurrently with routine CSF cell counts, but the value of CSF infection testing in otherwise healthy children is unknown.

OBJECTIVE

To determine the value of nonculture CSF infection testing in immune-competent children with normal CSF cell counts.

DESIGN, SETTING, AND PARTICIPANTS

This cross-sectional study reviewed screening and diagnostic tests in the electronic medical record system of a large academic tertiary care children's hospital. Records of children aged 0.5 to 18.9 years (n = 4083) who underwent lumbar puncture (n = 4811 procedures) in an inpatient or outpatient facility of Children's Hospital of Philadelphia between July 1, 2007, and December 31, 2016, were reviewed. Those with indwelling CSF shunts or catheters; those with active or past oncologic, immunologic, or rheumatologic conditions; or those taking immune-suppressing medications were excluded from analysis. This study was conducted from July 20, 2017, to March 13, 2019.

MAIN OUTCOMES AND MEASURES

Outcome variables included frequency of nonculture CSF infection testing and frequency of positive results in the entire cohort, and among those with normal cell counts. Normal cell counts were defined as CSF white blood cell counts lower than 5 cells/μL and CSF red blood cell counts lower than 500 cells/μL.

RESULTS

In total, 4811 lumbar puncture procedures were performed on 4083 unique children, with a median (range) age of 7.4 (0.5-18.9) years, 2537 boys (52.7%), and 3331 (69.2%) with normal CSF cell counts. At least 1 nonculture CSF infection test was performed on 1270 lumbar puncture specimens with normal cell counts (38.1%; 95% CI, 36%-40%), and more tests were performed in the summer months. Only 18 (1.4%; 95% CI, 0.9%-2.2%) of 1270 lumbar puncture specimens with normal cell counts had at least 1 nonculture infection test with a positive result; 2 of these 18 children required clinical intervention for their positive results, but each also had other clear clinical signs of infection.

CONCLUSIONS AND RELEVANCE

Nonculture CSF infection testing appeared to be common in immune-competent children with normal CSF cell counts, but positive results were uncommon and were not independently associated with clinical care; delaying the decision to send nonculture infection tests until CSF cell counts are available could reduce unnecessary diagnostic testing and medical costs, which may improve value-based care.

Preclinical Assessment of Leptin Transport into the Cerebrospinal Fluid in Diet-Induced Obese Minipigs

OBJECTIVE

A minipig model was employed to explore the changes in endogenous leptin transport into the central nervous system and in hypothalamic sensitivity to exogenous leptin when individuals are placed on high-fat diet (HFD) compared with standard diet.

METHODS

Serum and cerebrospinal fluid (CSF) leptin concentrations during 10 weeks of HFD versus standard diet and exogenous leptin-induced STAT3 phosphorylation in the hypothalamus of minipigs were assessed, and the hypothalamic leptin-sensitive cells were characterized by immunofluorescence.

RESULTS

The efficiency of the passage of endogenous blood-borne leptin into the CSF (measured as the log [CSF:serum leptin ratio]) decreased over time in minipigs fed a HFD (β = -0.04 ± 0.005 per kilogram of weight gain in HFD; P < 0.0001), while it remained stable in minipigs fed a standard diet. However, the ability of peripherally administered leptin to activate its receptor in hypothalamic neurons was preserved in obese minipigs at 10 weeks of HFD.

CONCLUSIONS

Together, these data are consistent with the existence of an early-onset tranport deficiency for endogenous circulating leptin into the brain in individuals developing obesity, preceding the acquisition of hypothalamic leptin resistance. Although additional studies are required to identify the underlying mechanisms, our study paves the way for the development of new preclinical pharmacological models targeting the restoration of the shuttling of peripheral leptin into the central nervous system to manage obesity.

Froin Syndrome After Spinal Cord Injury

BACKGROUND

Froin syndrome is characterized by xanthochromia and hypercoagulability of the cerebrospinal fluid (CSF) due to elevated protein levels. This entity results from blockage of the spinal canal by a mass lesion leading to an isolated caudal CSF space.

CASE DESCRIPTION

A 48-year-old male, who developed spasticity after a C6 spinal cord injury (SCI) 20 years earlier, presented with subobstruction of his intrathecal baclofen pump. A catheter access port aspiration revealed an extremely high protein concentration (38 g/L) with no signs of infection. Froin syndrome was confirmed when magnetic resonance imaging showed a complete obstruction of the spinal canal at the SCI level.

CONCLUSIONS

We report the first case of Froin syndrome after SCI. Froin syndrome can impact intrathecal drug delivery and CSF diagnostics.

Mollaret Meningitis with a High Level of Cytokines in the Cerebrospinal Fluid Successfully Treated by Indomethacin

A rare case of Mollaret meningitis characterized by four recurrent episodes of aseptic meningitis during a three-year period is reported. The patient showed a high fever and severe headache accompanied by a high level of cerebrospinal fluid (CSF) cytokines, such as interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF-α). The symptoms and high CSF cytokines were resolved immediately after introducing indomethacin treatment. Reactivation of the latent virus is considered to be the cause of this rare disease, and indomethacin is believed to inhibit the periodic abnormal generation of eicosanoid in the brain, resulting in a reduction in the fever and subsequent inflammation.

Cerebrospinal Fluid (CSF) Exchange with Artificial CSF Enriched with Mesenchymal Stem Cell Secretions Ameliorates Experimental Autoimmune Encephalomyelitis

The complexity of central nervous system (CNS) degenerative/inflammatory diseases and the lack of substantially effective treatments point to the need for a broader therapeutic approach to target multiple components involved in the disease pathogenesis. We suggest a novel approach directed for the elimination of pathogenic agents from the CNS and, in parallel, its enrichment with an array of neuroprotective substances, using a "cerebrospinal fluid (CSF) exchange" procedure, in which endogenous (pathogenic) CSF is removed and replaced by artificial CSF (aCSF) enriched with secretions of human mesenchymal stem cells (MSCs). MSCs produce a variety of neuroprotective agents and have shown beneficial effects when cells are transplanted in animals and patients with CNS diseases. Our data show that MSCs grown in aCSF secrete neurotrophic factors, anti-inflammatory cytokines, and anti-oxidant agents; moreover, MSC-secretions-enriched-aCSF exerts neuroprotective and immunomodulatory effects in neuronal cell lines and spleen lymphocytes. Treatment of experimental-autoimmune-encephalomyelitis (EAE) mice with this enriched-aCSF using an intracerebroventricular (ICV) CSF exchange procedure ("CSF exchange therapy") caused a significant delay in the onset of EAE and amelioration of the clinical symptoms, paralleled by a reduction in axonal damage and demyelination. These findings point to the therapeutic potential of the CSF exchange therapy using MSC-secretions-enriched-aCSF in inflammatory/degenerative diseases of the CNS.

Phase contrast MRI of creeping flows using stimulated echo

Creeping flows govern many important physiological phenomena such as elevated interstitial fluid flows in tumors, glymphatic flows in the brain, among other applications. However, few methods exist to measure such slow flows non-invasively in optically opaque biological tissues in vivo. Phase-contrast MRI is a velocimetry technique routinely used in the clinic to measure fast flows in biological tissues, such as blood and cerebrospinal fluid (CSF), in the order of cm/s. Use of this technique to encode slower flows is hampered by diffusion weighting and phase error introduced by gradient hardware imperfections. In this study, a new PC-MRI technique is developed using stimulated echo preparation to overcome these challenges. Flows as slow as 1 μm/s are measured and validated using controlled water flow through a pipe at 4.7 T. The error in measured flow rate obtained by integrating the measured velocity over the cross-sectional area of the pipe is less than 10%. The developed method was also able to capture slow natural convection flows appearing in liquids placed inside a horizontal bore magnet. Monitoring the 4D velocity vector field revealed that the natural convection flows decay exponentially with time. This method could be applied in future to study creeping flows, e.g. in tissue.

Biobanking of Cerebrospinal Fluid

Cerebrospinal fluid (CSF) is a physiologically essential fluid produced by the brain that is involved in protecting the brain and in the exchange of nutrients and waste products. CSF has long been utilized to confirm clinical suspicion of various infectious and inflammatory disorders, such as meningitis and multiple sclerosis. However, there has been increasing interest in collecting CSF in order to study the clinical significance of additional biomarkers. This chapter outlines the procedures necessary to collect, process, store, and utilize CSF obtained for the purposes of biobanking from both living and deceased patients.

THE COMPARATIVE ANALYSIS OF DIFFERENT TECHNIQUES OF LASER POLARIMETRY FOR DETERMINATION OF TIME OF DEATH IN THE STUDY OF POLYCRYSTALLINE FILMS OF CEREBROSPINAL FLUID

The estimation of death coming prescription (DCP) is one of the most important issues that confronts a medical examiner during the corpse examination right at the scene of death. The most promising biological object for the DCP estimation is cerebrospinal fluid. Aim - to compare the effectiveness of methods being used: stokes-polarimetry, stokes-colorimetry, autofluorescence polarimetry in order to improve the accuracy of DCP for the long - and short-term time intervals. The object of the study - cerebrospinal fluid from 75 cadavers (study group) and 20 live individuals (control group). Methods used: stokes polarimetry, stokes-colorimetry, autofluorescence polarimetry. When analyzing the image of the biological sample within the statistical analysis using the stokes polarimetry it is possible to obtain some quantitative characteristics about the amount of the statistical moments of the 1st - 4th orders, which can be used to find the relationship between them and the DCP. However, the coordinate and morphological structure of biological samples are ignored when using this approach. A correlation method in this context is more functional and sensitive. Due to this a higher accuracy of DCP is achieved in a short period. The analysis revealed that the spatial-frequency filtration of polarization-inhomogeneous images of polycrystal films of cerebrospinal fluid improves the time monitoring sensitivity of biochemical changes in optically active molecular compounds. Speaking about fluorescence microscopy - it carries the information about the concentration of molecular complexes of proteins, NADH, flavins, porphyrins, etc. As in the postmortem period the changes in the cerebrospinal fluid begin with the changes in the concentration of biochemical compounds, and crystalline changes are secondary, this method is the most effective for diagnosing the death coming prescription in the first 8 hours. The fluorescent methods of laser polarimetric are precise at a short interval of DCP estimation, and the polarization ones allow us to estimate this parameter at the long-term time intervals, though with less accuracy.

Quantitative and qualitative assessment of glymphatic flux using Evans blue albumin

BACKGROUND

The glymphatic system is a proposed pathway for clearance of proteins and macromolecules from brain, and disrupted glymphatic flux is implicated in neurological disease. We capitalized on colorimetric, fluorescent, and protein-binding properties of Evans blue to evaluate glymphatic flux.

NEW METHOD

Twenty-five μL of 1% Evans blue-labeled albumin (EBA) in artificial cerebrospinal fluid (aCSF) was injected into the intracisternal space of anesthetized postnatal day 17 rats. Serum was collected at various time points after injection (n = 37) and EBA was measured spectrophotometrically. In separate rats (n = 3), a cranial window was placed over the parietal cortex and EBA transit was evaluated using in vivo multiphoton microscopy. Separate rats (n = 6) were processed for immunohistochemistry to examine localization of EBA. In some rats, intracranial pressure (ICP) was increased via intracisternal injection of aCSF.

RESULTS

EBA was detected in serum as early as 30 min, was maximal at 4 h, and was undetectable at 72 h after intracisternal injection. Using intra-vital microscopy and immunohistochemistry EBA could be tracked from CSF to perivascular locations. Consistent with removal via glymphatic flux, increasing ICP to 40 mmHg accelerated transit of EBA from CSF to blood.

COMPARISON WITH EXISTING METHODS

Transit of EBA from CSF to serum could be quantified spectrophotometrically without radioactive labeling. Glymphatic flux could also be qualitatively evaluated using EBA fluorescence.

CONCLUSION

We present a novel technique for simultaneous quantitative and qualitative evaluation of glymphatic flux in rats.

NMR metabolomics of cerebrospinal fluid differentiates inflammatory diseases of the central nervous system

BACKGROUND

Myriad infectious and noninfectious causes of encephalomyelitis (EM) have similar clinical manifestations, presenting serious challenges to diagnosis and treatment. Metabolomics of cerebrospinal fluid (CSF) was explored as a method of differentiating among neurological diseases causing EM using a single CSF sample.

METHODOLOGY/PRINCIPAL FINDINGS

1H NMR metabolomics was applied to CSF samples from 27 patients with a laboratory-confirmed disease, including Lyme disease or West Nile Virus meningoencephalitis, multiple sclerosis, rabies, or Histoplasma meningitis, and 25 controls. Cluster analyses distinguished samples by infection status and moderately by pathogen, with shared and differentiating metabolite patterns observed among diseases. CART analysis predicted infection status with 100% sensitivity and 93% specificity.

CONCLUSIONS/SIGNIFICANCE

These preliminary results suggest the potential utility of CSF metabolomics as a rapid screening test to enhance diagnostic accuracies and improve patient outcomes.

Detection of cell-free DNA fragmentation and copy number alterations in cerebrospinal fluid from glioma patients

Glioma is difficult to detect or characterize using current liquid biopsy approaches. Detection of cell-free tumor DNA (cftDNA) in cerebrospinal fluid (CSF) has been proposed as an alternative to detection in plasma. We used shallow whole-genome sequencing (sWGS, at a coverage of < 0.4×) of cell-free DNA from the CSF of 13 patients with primary glioma to determine somatic copy number alterations and DNA fragmentation patterns. This allowed us to determine the presence of cftDNA in CSF without any prior knowledge of point mutations present in the tumor. We also showed that the fragmentation pattern of cell-free DNA in CSF is different from that in plasma. This low-cost screening method provides information on the tumor genome and can be used to target those patients with high levels of cftDNA for further larger-scale sequencing, such as by whole-exome and whole-genome sequencing.

[TIME SINCE DEATH ESTIMATION BY USING THE METHOD OF POLYCRYSTALLINE CEREBROSPINAL FLUID FILMS IMAGES MUTUAL POLARIZATION DEGREE LEVELS DISTRIBUTIONS TWO-DIMENSIONAL MAPPING WITH FINE-SCALE SPATIAL FREQUENCY FILTRATION]

Objective - to develop a method of two-dimensional Stokes-polarimetric spatial-frequency mapping of small-scale components of cerebrospinal fluid to improve the accuracy of post-mortem interval estimation. The object of the study was polycrystalline cerebrospinal fluid films taken from 69 corpses (the main study group) and 20 healthy volunteers (comparison group). For each sample, the coordinate distribution of the values of the complex degree of mutual polarization was determined in the optical arrangement of the Stokes polarimeter. The value of the statistical moments of 1 - 4 orders with further statistical processing was calculated. Time dependences of the variation of the value of the most sensitive statistical moments were built to achiev of values stabilization. The interval and the accuracy of the post-mortem interval were estimated by generalizing of the time dependences of the third and fourth order statistical moments of the polarization maps obtained by the two-dimensional mapping of the values distributions of the complex degree of mutual polarization of the small-scale component of polycrystalline networks of cerebrospinal fluid films. An interval of 10 h and the accuracy of post-mortem interval estimation ΔT = ± 12.5 min was established.

Integration of magnetic resonance imaging and protein and metabolite CSF measurements to enable early diagnosis of secondary progressive multiple sclerosis

Molecular networks in neurological diseases are complex. Despite this fact, contemporary biomarkers are in most cases interpreted in isolation, leading to a significant loss of information and power. We present an analytical approach to scrutinize and combine information from biomarkers originating from multiple sources with the aim of discovering a condensed set of biomarkers that in combination could distinguish the progressive degenerative phenotype of multiple sclerosis (SPMS) from the relapsing-remitting phenotype (RRMS). Methods: Clinical and magnetic resonance imaging (MRI) data were integrated with data from protein and metabolite measurements of cerebrospinal fluid, and a method was developed to sift through all the variables to establish a small set of highly informative measurements. This prospective study included 16 SPMS patients, 30 RRMS patients and 10 controls. Protein concentrations were quantitated with multiplexed fluorescent bead-based immunoassays and ELISA. The metabolome was recorded using liquid chromatography-mass spectrometry. Clinical follow-up data of the SPMS patients were used to assess disease progression and development of disability. Results: Eleven variables were in combination able to distinguish SPMS from RRMS patients with high confidence superior to any single measurement. The identified variables consisted of three MRI variables: the size of the spinal cord and the third ventricle and the total number of T1 hypointense lesions; six proteins: galectin-9, monocyte chemoattractant protein-1 (MCP-1), transforming growth factor alpha (TGF-α), tumor necrosis factor alpha (TNF-α), soluble CD40L (sCD40L) and platelet-derived growth factor AA (PDGF-AA); and two metabolites: 20β-dihydrocortisol (20β-DHF) and indolepyruvate. The proteins myelin basic protein (MBP) and macrophage-derived chemokine (MDC), as well as the metabolites 20β-DHF and 5,6-dihydroxyprostaglandin F1a (5,6-DH-PGF1), were identified as potential biomarkers of disability progression. Conclusion: Our study demonstrates, in a limited but well-defined and data-rich cohort, the importance and value of combining multiple biomarkers to aid diagnostics and track disease progression.

Cerebrospinal fluid lactate concentration and bacterial encephalitis diagnosis

OBJECTIVES

A French national study on infectious encephalitis enrolled 253 patients in 2007. Fifty-two per cent of patients had a proven etiological diagnosis; 16% had bacterial encephalitis. We aimed to assess the predictive value of CSF lactate concentration to diagnose bacterial encephalitis.

PATIENTS AND METHODS

Patients from the 2007 cohort whose CSF lactate concentration was available were included. Clinical and biological features associated with a bacterial etiology were assessed using univariate analysis and multivariate logistic regression. The ROC curve of CSF lactate concentration was used to define the most appropriate cut-off associated with bacterial etiology.

RESULTS

Fifty-seven patients (37 men, 20 women) were included. Ten patients had bacterial encephalitis, 20 patients had viral encephalitis. The mean CSF white blood cells (WBC), protein, glucose, and lactate levels were respectively 92 cells/mm³ (range: 0-450), 1.2g/L (range: 0.2-8.2), 3.9mmol/L (range: 0.8-8.8), and 2.8mmol/L (range: 0-9.4). In univariate analysis, CSF protein level (P<0.01), WBC count (P=0.02), and lactate concentration (P<0.01) were significantly associated with bacterial etiology. The only factor independently associated with bacterial etiology in the multivariate analysis was CSF lactate concentration. The area under the ROC curve of CSF lactate for the diagnosis of bacterial encephalitis was 0.86. The cut-off value of 3.4 mmol/L correctly classified 87.8% of patients with 70% sensitivity, 91.5% specificity, 64% positive predictive value, and 93% negative predictive value.

CONCLUSION

A high CSF lactate level seems to be a better predictor than WBC or proteins to differentiate bacterial encephalitis from other etiologies.

Comparison of Clinical Features and Prognostic Factors of Cryptococcal Meningitis Caused by Cryptococcus neoformans in Patients With and Without Pulmonary Nodules

Whether the clinical features of cryptococcal meningitis (CM) patients vary with the coexistence of pulmonary nodules is not clear. This study aimed to compare the clinical features of CM in patients with and without pulmonary nodules detected by chest computed tomography (CT). The medical records of CM patients hospitalized in Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology from January 1, 2010, to December 31, 2016, were retrospectively reviewed. Baseline demographics, laboratory and radiographic findings, clinical managements, and outcomes were analyzed. A total of 90 CM patients were enrolled. Forty (44.4%) patients had pulmonary nodules (PN-positive), and 50 (55.6%) patients had no pulmonary nodules (PN-negative). Compared with PN-negative patients, PN-positive patients had higher cerebrospinal fluid (CSF)/serum albumin ratios, higher rates of CSF protein > 1000 mg/L, CSF glucose < 2.5 mmol/L, worse overall treatment response, higher rates of abnormal head CT and magnetic resonance imaging manifestations, and more unfavorable clinical outcomes. Multivariate analysis showed that immunocompromise (p = 0.037) and CSF glucose < 2.5 mmol/L (p = 0.044) indicated poor outcome in PN-positive patients, while CSF glucose < 2.5 mmol/L (p = 0.025) also indicated poor outcome in PN-negative patients. Amphotericin B in the initial therapy was a protective factor for PN-negative patients (p = 0.008). Certain clinical features showed significant differences between CM patients with and without pulmonary nodules, and several independent contributing factors impacted the clinical outcomes for CM patients. Future studies should be performed to further examine these factors.