Cerebrospinal Fluid-Basic Concepts Review

Permeability of the blood-CSF barrier in MOGAD: clinical correlation based on the 2023 diagnostic criteria

BACKGROUND

The pathogenesis of myelin oligodendrocyte glycoprotein antibody-associated disease (MOGAD) is associated with damage to the blood-cerebrospinal fluid (CSF) barrier (BCB), but a specific correlation remains unclear. We used the newly proposed diagnostic criteria in 2023 with the aim to evaluate the permeability of the BCB in MOGAD.

METHODS

We retrospectively analyzed data from 48 eligible patients with MOGAD. Serum and CSF samples were collected simultaneously prior to initiation of immunotherapies at admission. Elevated CSF/serum albumin quotient (QAlb) and indicators of intrathecal immunoglobulin G (IgG) synthesis were calculated as indicators of BCB damage. The relationship between the parameters and clinical features, disease severity, and prognosis were analyzed.

RESULTS

Elevated QAlb levels were detected in 50% of patients, but only a small proportion of patients met the corresponding classifications of intrathecal IgG synthesis, namely IgG index >0.7 (10.4%), IgG synthesis rate >10 (6.2%), and local IgG synthesis rate >0 (8.1%). Elevated QAlb was significantly more common in patients with myelitis than in those with optic neuritis (p = 0.049). It was identified as an independent predictor of moderate-severe disease at admission (modified Rankin Scale [mRS]/Expanded Disability Status Scale [EDSS] ≥ 4). Moreover, elevated QAlb emerged as an independent risk factor for a poor long-term prognosis (mRS/EDSS ≥3 at the last follow-up).

CONCLUSIONS

BCB damage was common in MOGAD. Elevated QAlb could serve as a biomarker for evaluating disease severity at admission and predicting long-term prognosis.

Arterial pulsations and transmantle pressure synergetically drive glymphatic flow

Clearance of waste material from the brain by the glymphatic system results from net flow of cerebrospinal fluid (CSF) through perivascular spaces surrounding veins and arteries. In periarterial spaces, this bulk flow is directed from the cranial subarachnoid space towards the brain's interior. The precise pumping mechanism explaining this net inflow remains unclear. While in vivo experiments have shown that the pulsatile motion in periarterial spaces is synchronized with arterial pulsations, peristalsis alone has been deemed insufficient to explain bulk flow. In this study we examine an alternative mechanism based on the interaction between arterial pulsations and fluctuations in transmantle pressure. Previously studied using pressure data from a hydrocephalus patient, this mechanism is analyzed here in healthy subjects using in vivo flow measurements obtained via phase-contrast magnetic resonance imaging. Arterial pulsations are derived from flow-rate measurements of arterial blood entering the cranial cavity, while transmantle-pressure fluctuations are computed using measurements of CSF flow in the cerebral aqueduct. The two synchronized waveforms are integrated into a canonical multi-branch model of the periarterial spaces, yielding a closed-form expression for the bulk flow. The results confirm that the dynamic interactions between arterial pulsations and transmantle pressure are sufficient to generate a positive inflow along periarterial spaces.

Non-invasive MRI measurements of age-dependent in vivo human glymphatic exchange using magnetization transfer spin labeling

BACKGROUND

The water exchange between brain parenchyma and cerebrospinal fluid (CSF) is considered to be responsible for glymphatic clearance of solutes and metabolic wastes from the brain, including amyloid-β, a biomarker in neurodegeneration. Despite the potential significance, no noninvasive technique for in vivo measurement of parenchyma-CSF water exchange has been demonstrated in humans, capable of investigating age-related changes in glymphatic clearance.

PURPOSE

To demonstrate a noninvasive, translatable MRI technique capable of measuring glymphatic water exchange in humans and to apply this technique to examine age-related changes in the glymphatic exchange measures in healthy subjects.

METHODS

Repeating on-resonance magnetization transfer (MT) RF pulses were applied to saturate macromolecules within the brain parenchyma and label its interstitial water, followed by measuring partial CSF saturation resulting from the parenchyma-CSF water exchange. Bloch simulations and phantom experiments determined the extent of direct CSF saturation by the MT pulses. An additional labeling nulling experiment was performed by preemptively saturating parenchyma spins to disable the following MT-based spin labeling, to examine non-exchange contributions to the observed CSF saturation. These techniques were applied to young (n = 6; ages 25-41) and elder (n = 6; ages 53-66) healthy participants to examine age-related changes in their saturation-based exchange measurements.

RESULTS

Both Bloch simulations and phantom experiments indicated small (0.4-0.7 %) direct CSF saturation when B0 inhomogeneities and CSF T2 variations were considered. A statistically significant (P = 0.037) difference was observed in the average CSF saturation ratio within the subarachnoid space (SAS) between the young (4.7 %±0.5 %) and the elder (3.5 %±1.2 %) subjects, with their ages negatively correlating with this exchange metric (R2=0.34, P = 0.046). The substantial saturation reductions in the labeling nulling experiment (40-50 % in young; 10-30 % in elder) suggested parenchyma-CSF exchange as a substantial source of the observed saturation signal. These findings survived when the exchange metrics were compensated for potential atrophy-related dilution effect caused by variations in intra-voxel CSF volume.

CONCLUSION

Optimized MT-based parenchyma spin labeling followed by CSF partial saturation measurement demonstrated feasibility of a noninvasive MRI approach to detect glymphatic water exchange between human brain parenchyma and CSF in vivo, with statistically significant findings of age-related differences in the exchange measures.

Unravelling disease complexity: integrative analysis of multi-omic data in clinical research

INTRODUCTION

A holistic view on biological systems is today a reality with the application of multi-omic technologies. These technologies allow the profiling of genome, epigenome, transcriptome, proteome, metabolome as well as newly emerging 'omes.' While the multiple layers of data accumulate, their integration and reconciliation in a single system map is a cumbersome exercise that faces many challenges. Application to human health and disease requires large sample sizes, robust methodologies and high-quality standards.

AREAS COVERED

We review the different methods used to integrate multi-omics, as recent ones including artificial intelligence. With proteomics as an anchor technology, we then present selected applications of its data combination with other omics layers in clinical research, mainly covering literature from the last five years in the Scopus and/or PubMed databases.

EXPERT OPINION

Multi-omics is powerful to comprehensively type molecular layers and link them to phenotype. Yet, technologies and data are very diverse and still strategies and methodologies to properly integrate these modalities are needed.

Bromocriptine for Idiopathic Intracranial Hypertension: A Retrospective Multicenter Cohort Study

Introduction

Idiopathic Intracranial Hypertension (IIH) is a disorder characterized by elevated intracranial pressure without an identifiable cause, commonly affecting young obese women. Current treatment strategies, including weight loss, acetazolamide, and surgical interventions, have limitations due to side effects, adherence challenges, and potential complications. Bromocriptine, a dopamine D2 receptor agonist, has emerged as a potential novel therapy due to its metabolic effects. This study aims to evaluate the safety and efficacy of bromocriptine in IIH management through a retrospective cohort analysis.

Methods

A retrospective analysis was conducted, focusing on patients with IIH. Propensity score matching was applied to balance baseline characteristics, including age, sex, race, and BMI, between the bromocriptine and control groups. Key outcome measures, papilledema, headache severity, refractory IIH status, and acetazolamide dose dependency, were assessed at multiple follow-up intervals.

Results

The bromocriptine group demonstrated significant improvement in papilledema and headache severity over 24 months, with early effects observed at one month. There was a marked reduction in refractory IIH (30.66% lower incidence at 24 months, p<0.0001) and reduced dependency on acetazolamide from three months onward (p=0.0246). The safety profile was favorable, with comparable adverse event rates to controls, although allergic skin reactions were noted in the bromocriptine group.

Conclusion

Bromocriptine shows promise as an effective and safe therapeutic option for IIH, with sustained improvement in clinical parameters and reduced reliance on conventional treatment. Future randomized controlled trials are needed to confirm these findings and explore optimal dosing strategies.

Long-term CSF responses in adult patients with spinal muscular atrophy type 2 or 3 on treatment with nusinersen

BACKGROUND

5q-associated spinal muscular atrophy (SMA) is a monogenic disease causing progressive alpha motor neuron degeneration, muscle atrophy, and weakness. Intrathecal therapy with the antisense oligonucleotide nusinersen modifies the disease course. However, biomarkers for understanding underlying molecular pathomechanisms and monitoring therapy are not yet known.

METHODS

A total of 130 cerebrospinal fluid (CSF) samples from 24 adult patients with SMA type 2 or 3 were collected over 3.5 years, and CSF proteome was analyzed using mass spectrometry (MS). By applying two complementary MS protein quantification methods, label-free quantification (LFQ) and tandem mass tag (TMT) isotopic labeling, specific protein patterns reflecting changes in the CSF in response to nusinersen therapy were identified. These results were combined with cellular and metabolic profiles.

RESULTS

Nusinersen therapy led to a median motor function improvement of 2.2 Hammersmith Functional Motor Scale-Expanded points after 10 months and 2.6 points after 34 months. CSF macrophages increased in number and showed an altered morphology. Albumin quotient (qAlb), glucose, and lactate concentrations were inversely correlated with clinical improvement. MS analysis of CSF identified 1,674 (TMT) and 441 (LFQ) proteins. Protein profiles reflected reduced inhibition of "nervous system development" and "axogenesis" pathways under therapy. In addition, clinical improvement was associated with upregulation of the interacting proteins α-dystroglycan and beta-1,4-glucuronyltransferase 1, reduction of complement factors, negative correlation in immunoglobulin- and B cell-related pathways, and reduction of cellular mediators such as lymphocytes.

CONCLUSION

The present multi-proteomic analysis contributes to the understanding of the molecular mechanisms underlying nusinersen's therapeutic effects and offers potential biomarkers for monitoring treatment response in SMA.

A review of cerebrospinal fluid circulation with respect to Chiari-like malformation and syringomyelia in brachycephalic dogs

Cerebrospinal fluid (CSF) plays a crucial role in maintaining brain homeostasis by facilitating the clearance of metabolic waste and regulating intracranial pressure. Dysregulation of CSF flow can lead to conditions like syringomyelia, and hydrocephalus. This review details the anatomy of CSF flow, examining its contribution to waste clearance within the brain and spinal cord. The review integrates data from human, canine, and other mammalian studies, with a particular focus on brachycephalic dogs. Certain dog breeds exhibit a high prevalence of CSF-related conditions due to artificial selection for neotenous traits, making them valuable models for studying analogous human conditions, such as Chiari-like malformation and syringomyelia associated with craniosynostosis. This review discusses the anatomical features specific to some brachycephalic breeds and the impact of skull and cranial cervical conformation on CSF flow patterns, providing insights into the pathophysiology and potential modelling approaches for these conditions.

Comparative analysis of post-mortem drug concentrations in cerebrospinal fluid and blood

This study aimed to compare the concentration of various xenobiotics in both cerebrospinal fluid (CSF) and blood. We examined 175 autopsy cases covering a wide range of ages, causes of death, and drug ingestion histories, with cerebrospinal fluid and blood samples available for toxicological testing. Analytes studied included opioids, benzodiazepines, antidepressants, antipsychotics, and illicit substances such as cannabinoids, stimulants and new psychoactive substances, including synthetic cathinones and synthetic cannabinoids. We found that concentrations in CSF were generally lower than in blood. A significant correlation was observed between drug concentrations in CSF and blood for many analytes (p < 0.05). However, the strength and direction of the correlation varied considerably depending on the physicochemical properties of the drugs, suggesting that a 'one size fits all' model may not be applicable. The results indicate that cerebrospinal fluid (CSF) can be used to detect a variety of xenobiotics, particularly amphetamines, synthetic cathinones and synthetic cannabinoids, in cases where conventional biological materials are not available. Additionally, using the results obtained in the future can lead to a better understanding of pharmacokinetic processes and the effect of post-mortem redistribution. Further research is needed to refine our understanding of these relationships.

Nuclear Cerebrospinal Fluid Imaging: Guide to Procedures and Interpretation

Cerebrospinal fluid (CSF) is an essential component of the central nervous system, and disruption of normal CSF flow from the lateral ventricles to the subarachnoid spaces around the brain and spinal canal can have serious consequences. Nuclear imaging may be useful to help diagnose abnormalities in CSF flow; cisternograms can be used to assess for CSF leaks or normal-pressure hydrocephalus, and shuntograms can be used to evaluate for CSF shunt malfunction. The authors review normal and pathologic findings and pitfalls of cisternography and shuntogram examinations. ©RSNA, 2025.

Plasmonic Biosensors for Health Monitoring: Inflammation Biomarker Detection

Surface plasmon resonance (SPR) and localized SPR (LSPR) biosensors have emerged as viable technologies in the clinical detection of biomarkers for a wide array of health conditions. The success of SPR biosensors lies in their ability to monitor in real-time label-free biomarkers in complex biofluids. Recent breakthroughs in nanotechnology and surface chemistry have significantly improved this feature, notably from the incorporation of advanced nanomaterials including gold nanoparticles, graphene, and carbon nanotubes providing better SPR sensor performance in terms of detection limits, stability, and specificity. Recent progress in microfluidic integration has enabled SPR biosensors to detect multiple biomarkers simultaneously in complex biological samples. Taken together, these advances are closing the gap for their use in clinical diagnostics and point-of-care (POC) applications. While broadly applicable, the latest advancements in plasmonic biosensing are overviewed using inflammation biomarkers C-reactive protein (CRP), interleukins (ILs), tumor necrosis factor-α (TNF-α), procalcitonin (PCT), ferritin, and fibrinogen for a series of conditions, including cardiovascular diseases, autoimmune disorders, infections, and sepsis, as a key example of plasmonic biosensors for clinical applications. We highlight developments in sensor design, nanomaterial integration, surface functionalization, and multiplexing and provide a look forward to clinical applications by assessing the current limitations and exploring future directions for translating SPR biosensors for diagnostics and health monitoring. By enhancement of diagnostic accuracy, reproducibility, and accessibility, particularly in POC settings, SPR biosensors have the potential to significantly contribute to personalized healthcare and bring real-time, high-precision diagnostics to the forefront of clinical practice.

Causes of Intracranial Hypotension: Spontaneous, Traumatic, and Iatrogenic Cerebrospinal Fluid Leaks

Cerebrospinal fluid leaks are important to recognize because they can cause debilitating symptoms for patients and have life-threatening complications. Leakage of cerebrospinal fluid (CSF) from the subarachnoid space can occur at the cranial or spinal level, with distinct clinical presentations, diagnostic evaluations, and treatment modalities depending on the type and location of the leak. Spontaneous, traumatic, and iatrogenic spinal CSF leaks cause reduced intracranial CSF volume and the clinicoradiologic syndrome commonly called "intracranial hypotension". This review discusses the clinical presentations, etiologies, and risk factors of spinal and cranial CSF leaks.

A Protocol for Determination of Proteinogenic Amino Acids in Biological Fluids by the High-Speed UHPLC-MS Method: Application on Transgenic Spontaneously Hypertensive Rat-24 Plasma and Cerebrospinal Fluid Samples

Recently, proteinogenic amino acids have become very interesting molecules, accompanied by a large variety of metabolic processes in humans and are associated with various diseases. In the era of system biology, including a broad spectrum of associated disciplines (e.g., metabolomics, lipidomics, proteomics, etc.), the possibility of identifying trustworthy biomarkers of diseases becomes much more likely. Changes in amino acid levels in plasma, serum, or cerebrospinal fluid reflect physiological or pathological conditions and, therefore, their regular monitoring can lead to early detection of the occurrence of a disease. Therefore, the exact determination of amino acids in biological fluids is of great importance. However, it is necessary to dispose with an effective, accurate, precise, selective, and robust analytical method. This protocol describes the complex procedure of amino acid analysis based on a combination of UHPLC with single quadrupole MS. The protocol presents a highly reproducible and robust methodology that has already been established in the quality control of biopharmaceuticals and determination of proteinogenic amino acids in urine in our laboratory. Here, the application potential is extended to the most frequently investigated biological fluid, that is, plasma and to the cerebrospinal fluid, which is investigated in many neurological conditions.

CSF production rate, resistance to reabsorption, and intracranial pressure: a systematic review and meta-analysis

Davson's equation relates the state of stable intracranial pressure (ICP) to the production rate of CSF (IF) and resistance to CSF outflow (ROUT). Both parameters are assumed to be independent of ICP, but results are conflicting. The objective is to define the relationship between ICP, IF and ROUT using a systematic literature review. Medline and Embase were searched from inception up to 12 February 2024. Experimental studies exploring the association between ICP, IF, and ROUT were included. Individual measurements of ICP, IF and/or ROUT were extracted from tables or graphs, alongside descriptive parameters (population, ICP measurement site, disease, and computational method). Linear regression and mixed effects models were applied. From 1304 references, 25 articles were included in our meta-analysis. IF is approximately constant across all pathologies independent of the ICP level, population, disease, ICP measurement site and the measurement/estimation method. Conversely, ICP was positively correlated with ROUT. The intercorrelation, however, differed by population, disease, ICP measurement site and estimation method. Additionally, IF derived from Davson's Equation compared with the measured IF were similar for patients with hydrocephalus but differed for patients with acute brain injury. Davson's Equation describes the various components of cerebrospinal fluid dynamics. The results underline important caveats for its use in patients with acute brain injury wherein the estimated values differ from the measured ones. Overall, additional metrics describing the cerebrovascular system or the underlying disease have to be taken into account for more accurate estimations.

An Improved Method for Extracting Rat Cerebrospinal Fluid with Repeatable Large-Scale Collection

The aim of this study was to explore an improved method for extracting rat cerebrospinal fluid (CSF), observing the impact on animal health under conditions of large-scale CSF collection and evaluating the feasibility of repeated collections. A total of 20 rats were anesthetized and fixed in a stereotactic frame. A 26G scalp needle, combined with a 1 mL syringe, was used to puncture the atlanto-occipital membrane and collect approximately 170 μL of CSF. CSF was collected twice within 14 days. During the study, animals were monitored daily for food intake, body weight, and hematological parameters, and at the end of the study, histopathological examination was performed. The health of the animals remained good, and repeated CSF collections were feasible. The success rate of the procedure was 100%, with blood contamination in the CSF decreasing from 70% in the first collection to 35% in the second. This technique is convenient, accurate, and suitable for widespread applications.

SARS-CoV-2 Infection of the Central Nervous System: A Case Report

Central nervous system (CNS) infections caused by SARS-CoV-2 are uncommon. This case report describes the clinical progression of a 92-year-old female who developed a persistent neuroinfection associated with SARS-CoV-2. The patient initially presented with progressive fatigue, catarrhal symptoms, and a fever (38.6 °C). Initial laboratory findings revealed hypoxemia (O2 saturation 79.8%), acidosis (pH 7.3), an elevated C-reactive protein (CRP) level of 14.8 mg/L, and a high D-dimer level (2.15 µg/mL). Nasopharyngeal (NP) antigen and RT-PCR tests confirmed SARS-CoV-2 infection, and an NP swab also detected penicillin- and ampicillin-resistant Staphylococcus aureus. She was admitted for conservative management, including oxygen supplementation, IV fluids, and prophylactic anticoagulation. Subsequently, she developed neurological symptoms-lethargy, discoordination, and impaired communication-without signs of meningism. Cerebrospinal fluid (CSF) analysis identified SARS-CoV-2 RNA (Ct = 29) on RT-PCR, while bacterial cultures remained negative. Treatment was intensified to include 10% mannitol, dexamethasone, and empiric ceftriaxone. Despite these interventions, the patient remained somnolent, with a Glasgow Coma Scale (GCS) score of 10. Upon discharge, her GCS had improved to 14; however, she continued to experience lethargy and cognitive issues, commonly described as "brain fog". Inflammatory markers remained elevated (CRP 23 mg/L) and repeat RT-PCR of CSF confirmed a persistent SARS-CoV-2 presence (Ct = 31). This case underscores the potential for SARS-CoV-2 to cause prolonged CNS involvement, leading to persistent neurological impairment despite standard therapy. Further research is essential to clarify the pathophysiology of and determine optimal management for SARS-CoV-2 neuroinfections.

Preventing acute neurotoxicity of CNS therapeutic oligonucleotides with the addition of Ca2+ and Mg2+ in the formulation

Oligonucleotide therapeutics (ASOs and siRNAs) have been explored for modulation of gene expression in the central nervous system (CNS), with several drugs approved and many in clinical evaluation. Administration of highly concentrated oligonucleotides to the CNS can induce acute neurotoxicity. We demonstrate that delivery of concentrated oligonucleotides to the CSF in awake mice induces acute toxicity, observable within seconds of injection. Electroencephalography and electromyography in awake mice demonstrated seizures. Using ion chromatography, we show that siRNAs can tightly bind Ca2+ and Mg2+ up to molar equivalents of the phosphodiester/phosphorothioate bonds independently of the structure or phosphorothioate content. Optimization of the formulation by adding high concentrations (above biological levels) of divalent cations (Ca2+ alone, Mg2+ alone, or Ca2+ and Mg2+) prevents seizures with no impact on the distribution or efficacy of the oligonucleotide. The data here establish the importance of adding Ca2+ and Mg2+ to the formulation for the safety of CNS administration of therapeutic oligonucleotides.

Navigating the Alzheimer's Biomarker Landscape: A Comprehensive Analysis of Fluid-Based Diagnostics

BACKGROUND

Alzheimer's disease (AD) affects a significant portion of the aging population, presenting a serious challenge due to the limited availability of effective therapies during its progression. The disease advances rapidly, underscoring the need for early diagnosis and the application of preventative measures. Current diagnostic methods for AD are often expensive and invasive, restricting access for the general public. One potential solution is the use of biomarkers, which can facilitate early detection and treatment through objective, non-invasive, and cost-effective evaluations of AD. This review critically investigates the function and role of biofluid biomarkers in detecting AD, with a specific focus on cerebrospinal fluid (CSF), blood-based, and saliva biomarkers.

RESULTS

CSF biomarkers have demonstrated potential for accurate diagnosis and valuable prognostic insights, while blood biomarkers offer a minimally invasive and cost-effective approach for diagnosing cognitive issues. However, while current biomarkers for AD show significant potential, none have yet achieved the precision needed to replace expensive PET scans and CSF assays. The lack of a single accurate biomarker underscores the need for further research to identify novel or combined biomarkers to enhance the clinical efficacy of existing diagnostic tests. In this context, artificial intelligence (AI) and deep-learning (DL) tools present promising avenues for improving biomarker analysis and interpretation, enabling more precise and timely diagnoses.

CONCLUSIONS

Further research is essential to confirm the utility of all AD biomarkers in clinical settings. Combining biomarker data with AI tools offers a promising path toward revolutionizing the personalized characterization and early diagnosis of AD symptoms.

An Association Between Fetal Subarachnoid Space and Various Pathologies Using MR Imaging

Background/Objectives: This study aimed to explore a relationship between the fetal subarachnoid space (SAS) width and various fetal pathologies, employing fetal brain MRI scans. Methods: A retrospective collection of fetal brain MRI scans of 78 fetuses was performed with sonographic indications of microcephaly, macrocephaly, or fetal growth restriction (FGR), during a 7-year period at a single tertiary center. The SAS width (named the SAS index) was manually measured in millimeters in ten specific anatomical locations (four in the axial plane and six in the coronal plane), and then converted to centiles by comparing it to (previously collected) data of apparently healthy fetuses. We evaluated the median SAS centiles using the Kruskal-Wallis and Mann-Whitney U tests for statistical comparison. Results: Seventy-eight subjects (mean gestational age of MRI scan 34.2 ± 2.2 weeks) were evaluated. The median SAS centiles were consistently higher in the macrocephaly group compared to the microcephaly group in all ten anatomical locations (statistically significant except coronal left inferior temporal gyri). Most pronounced difference was displayed in the insula gyri (axial and coronal). The median SAS centiles were higher in the microcephaly group when compared with FGR across all ten anatomical locations (all were statistically significant except for coronal frontal and insula gyri), and the maximal difference was found in the frontal gyri of both planes. The median SAS indexes (IQR) of the three groups in millimeters: macrocephaly 91.55 (86.35-101.05), microcephaly 59.46 (50.00-66.91), and FGR 53.21 (49.71-59.10), p < 0.001. Conclusions: We found a statistically significant association between the fetal subarachnoid space and various fetal pathologies: macrocephaly, microcephaly, and FGR.

The Blood-Cerebrospinal Fluid Barrier Dysfunction in Brain Disorders and Stroke: Why, How, What For?

Ischemic stroke (IS) results in the interruption of blood flow to the brain, which can cause significant damage. The pathophysiological mechanisms of IS include ionic imbalances, oxidative stress, neuroinflammation, and impairment of brain barriers. Brain barriers, such as the blood-brain barrier (BBB) and the blood-cerebrospinal fluid (CSF) barrier (B-CSF), protect the brain from harmful substances by regulating the neurochemical environment. Although the BBB is widely recognized for its crucial role in protecting the brain and its involvement in conditions such as stroke, the B-CSF requires further study. The B-CSF plays a fundamental role in regulating the CSF environment and maintaining the homeostasis of the central nervous system (CNS). However, the impact of B-CSF impairment during pathological events such as IS is not yet fully understood. In conditions like IS and other neurological disorders, the B-CSF can become compromised, allowing the entry of inflammatory substances and increasing neuronal damage. Understanding and preserving the integrity of the B-CSF are crucial for mitigating damage and facilitating recovery after ischemic stroke, highlighting its fundamental role in regulating the CNS during adverse neurological conditions.

Influencing factors of glymphatic system during perioperative period

The glymphatic system is a functional cerebrospinal fluid circulatory system that uses peri-arterial space for inflow of cerebrospinal fluid and peri-venous space for efflux of cerebrospinal fluid from brain parenchyma. This brain-wide fluid transport pathway facilitates the exchange between cerebrospinal fluid and interstitial fluid and clears metabolic waste from the metabolically active brain. Multiple lines of work show that the glymphatic system is crucial to normal brain functions, and the dysfunction of the glymphatic system is closely associated with various neurological disorders, including aging, neurodegeneration, and acute brain injury. Currently, it is common to explore the functional and molecular mechanisms of the glymphatic system based on animal models. The function of glymphatic system during perioperative period is affected by many factors such as physiological, pathological, anesthetic and operative methods. To provide a reference for the interpretation of the results of glymphatic system studies during perioperative period, this article comprehensively reviews the physiological and pathological factors that interfere with the function of the glymphatic system during perioperative period, investigates the effects of anesthetic drugs on glymphatic system function and the potential underlying mechanisms, describes operative methods that interfere with the function of the glymphatic system, and potential intervention strategies based on the glymphatic system. Future, these variables should be taken into account as critical covariates in the design of functional studies on the glymphatic system.

Which compartments of the optic nerve and its sheath are associated with intracranial pressure? An exploratory study

BACKGROUND AND PURPOSE

The optic nerve sheath diameter (ONSD) is a commonly used estimate of intracranial pressure (ICP). The rationale behind this is that pressure changes in the cerebrospinal fluid affect the optic nerve subarachnoid space (ONSAS) thickness. Still, possible effects on other compartments of the optic nerve sheath (ONS) have not been studied. This is the first study ever to analyze all measurable compartments of the ONS for associations with elevated ICP.

METHODS

We measured changes in ICP and changes in ONS compartments in 75 patients treated with invasive ICP monitoring at the Karolinska University Hospital. Associations between changes in ICP and changes in ONS compartments were estimated with generalized estimating equations. The potential to identify elevated ICP was assessed with the area under the receiver operating characteristic curve (AUROC) for ONS compartments associated with ICP changes.

RESULTS

Both ONSAS and perioptic dura mater thickness were significantly associated with changes in ICP in multivariable modeling. ONSAS was the only compartment that independently predicted changes in ICP, with an AUROC of 0.69 for predicting ICP increase. Still, both the perioptic dura mater thickness and the optic nerve diameter added value in predicting ICP changes in multivariable modeling.

CONCLUSIONS

The results from this study challenge the current understanding of the mechanism behind the association between ICP and ONSD. Contrary to the common opinion that ONSAS is the only affected compartment, this study shows a more complex picture. It suggests that all ONS compartments may add value in predicting changes in ICP.

Postmortem biochemistry of GFAP, NSE and S100B in cerebrospinal fluid and in vitreous humor for estimation of postmortem interval: a pilot study

Postmortem interval (PMI) is a challenging issue in forensic practice. Although postmortem biomarkers of traumatic brain injury (TBI) are recognised as an emerging resource for PMI estimation, their role remains controversial. This study aims to evaluate postmortem concentrations of three TBI biomarkers (GFAP, NSE and S100B) in two matrices (cerebrospinal fluid and vitreous humor), in order to find out if these markers could be adopted in PMI estimation. Thirty-five deceased individuals with known PMI who underwent forensic autopsy at the University of Parma were examined. Matrices were collected during autopsy, then biomarker concentrations were determined through the enzyme-linked immunosorbent assay. Statistical significance of the data in relation to PMI was studied. The correlation of biomarkers with PMI, examined with samples divided into six groups according to the number of days elapsed since death, was not statistically significant, although S100B in cerebrospinal fluid showed an increasing trend in cases from 1 to 5 days of PMI. Comparison between cases with 1 day of PMI and those with 2 or more days of PMI showed a statistically significant correlation for GFAP and NSE in cerebrospinal fluid. GFAP and NSE in cerebrospinal fluid represent appropriate biomarkers in PMI estimation to distinguish cases with one day of PMI from those with two or more days of PMI. The current study was limited by the scarcity of the cohort and the narrow spectrum of cases. Further research is needed to confirm these observations.

Potential for and challenges of menstrual blood as a non-invasive diagnostic specimen: current status and future directions

Menstrual blood, which is often discarded as a waste product, has emerged as a valuable source of health information. The components of menstrual blood, such as endometrial cells, immune cells, proteins, and microbial signatures, provide insights into health. Studies have shown encouraging results for using menstrual blood to diagnose a variety of conditions, including hormonal imbalances, cervical cancer, endometriosis, chlamydia, diabetes, and other endocrine disorders. This review examines the potential of menstrual blood as a non-invasive diagnostic specimen, exploring its composition, promising applications, and recent advances. This review also discusses challenges to utilizing menstrual blood testing, including ethical considerations, the lack of standardized collection protocols, extensive validation studies, and the societal stigma around menstruation. Overcoming these challenges will open new avenues for personalized medicine and revolutionize healthcare for individuals who menstruate.

Inside the Brain: Cerebrospinal Fluid Insights in Meningitis

Background Our study focused on meningitis, an infection that can spread through the bloodstream as a primary or secondary infection from other body parts, such as sinuses, ears, and lungs. It can affect patients who have experienced trauma or surgery, as well as those with congenital defects like spina bifida. Specifically, we examined bacterial, viral, and tuberculous meningitis (TBM) cases. The primary method for confirming the diagnosis of these types of meningitis is to analyze the cerebrospinal fluid (CSF). Early diagnosis can utilize cytological and biochemical parameters. Our objective is to determine CSF's cytological and biochemical profile in patients with these specific types of meningitis. Methods A study was carried out at the central pathology lab from October 24, 2017, to April 24, 2018. CSF samples from suspected meningitis patients were examined for various parameters, including hematological, biochemical, microbiological, and cytomorphological aspects and specific tests for bacterial, fungal, and TBM. The study focused on patients aged 16 and above, excluding those under 16, non-compliant patients, and individuals with specific health conditions. Data were analyzed using IBM SPSS Statistics for Windows, Version 20 (Released 2011; IBM Corp., Armonk, New York, United States), and the results were presented through the use of mean, standard deviation, and percentages. Statistical tests were utilized to compare categorical variables and mean, with a significance level of p<0.05. Results We included a total of 156 cases, with the mean age of presentation being 56.628 years. The male-to-female ratio was 1.0526:1. Of the patients, 81 (52.1%) had been diagnosed with TBM, had elevated adenosine deaminase (ADA) levels of 48.8733±37.43740 IU/L, and CSF lymphocytosis (99%). Additionally, cases of bacterial meningitis showed markedly raised mean total leukocyte count (TLC) of 2085.50±445.47727 cells/mm3 and mean CSF protein levels of 349.45±113.73105 mg/dL. The study found a significant increase in protein levels and a decrease in glucose levels in the CSF of TBM and bacterial meningitis patients compared to those with other causes of meningitis (p<0.001). Guillain-Barre syndrome (GBS) and multiple sclerosis (MS) patients had TLC and ADA within normal limits. CSF ADA level greater than 6 IU/L showed a sensitivity of 97.53% and a specificity of 96.0%, making it the most specific test. A protein level in the CSF greater than 45 mg/dL demonstrated a sensitivity of 98.78% and a specificity of 24.32%, indicating it is sensitive but less specific in diagnosing TBM. Lymphocytic predominance, defined as TLC of more than 5 cells/mm3 with at least 50% of the cells being lymphocytes in the CSF of TBM patients, showed a sensitivity of 97.53% and a specificity of 6.67%. CSF glucose had a sensitivity of 38.27%, making it the least reliable indicator for diagnosing meningitis. Conclusion The CSF analysis is the primary diagnostic method for detecting meningitis. Its cost-effectiveness is a key factor, especially for patients from lower socioeconomic backgrounds in government medical colleges in India, where access to expensive diagnostic tests is limited. The efficiency of CSF analysis for early diagnosing different types of meningitis aids in management, helping to prevent complications and fatal outcomes.

NfL concentration in CSF is a quantitative marker of the rate of neurodegeneration in aging and Huntington's disease: a semi-mechanistic model-based analysis

The concentrations of neurofilament light chain (NfL) in cerebrospinal fluid (CSF) and plasma have become key biomarkers of many neurodegenerative diseases, including Huntington's Disease (HD). However, the relationship between the dynamics of NfL concentrations in CSF and the time-course of neurodegeneration (whole brain atrophy) has not yet been described in a quantitative and mechanistic manner. Here, we present a novel semi-mechanistic model, which postulates that the amount of NfL entering the CSF corresponds to the amount of NfL released from damaged neurons, whose degeneration results in a decrease in brain volume. In mathematical terms, the model expresses the NfL concentration in CSF in terms of the NfL concentration in brain tissue, the rate of change of whole brain volume and the CSF flow rate. To test our model, we used a non-linear mixed effects approach to analyze NfL and brain volume data from the HD-CSF study, a 24-month prospective study of individuals with premanifest HD, manifest HD and healthy controls. The time-course of whole brain volume, obtained from MRI, was represented empirically by a 2nd order polynomial, from which its rate of change was computed. CSF flow rates in healthy and HD populations were taken from recent literature data. By estimating the NfL concentration in brain tissue, the model successfully described the time-course of the NfL concentration in CSF in both HD subjects and healthy controls. Furthermore, the model-derived estimate of NfL concentration in brain agreed well with recent direct experimental measurements. The consistency of our model with the NfL and brain volume data suggests that the NfL concentration in CSF reflects the rate, rather than the extent, of neurodegeneration and that the increase in NfL concentration over time is a measure of the accelerating rate of neurodegeneration associated with aging and HD. For HD subjects, the degree of acceleration was found to increase markedly with the number of CAG repeats on their HTT gene. The application of our semi-mechanistic NfL model to other neurodegenerative diseases is discussed.

Human Cerebrospinal Fluid Sample Preparation and Annotation for Integrated Lipidomics and Metabolomics Profiling Studies

Cerebrospinal fluid (CSF) is a metabolically diverse biofluid and a key specimen for exploring biochemical changes in neurodegenerative diseases. Detecting lipid species in CSF using mass spectrometry (MS)-based techniques remains challenging because lipids are highly complex in structure, and their concentrations span over a broad dynamic range. This work aimed to develop a robust lipidomics and metabolomics method based on commonly used two-phase extraction systems from human CSF samples. Prioritizing lipid detection, biphasic extraction methods, Folch, Bligh and Dyer (B&D), Matyash, and acidified Folch and B&D (aFolch and aB&D) were compared using 150 μL of human CSF samples for the simultaneous extraction of lipids and metabolites with a wide range of polarity. Multiple chromatographical separation approaches, including reversed-phase liquid chromatography (RPLC), hydrophilic interaction liquid chromatography (HILIC), and gas chromatography (GC), were utilized to characterize human CSF metabolome. The aB&D method was found as the most reproducible technique (RSD < 15%) for lipid extraction. The aB&D and B&D yielded the highest peak intensities for targeted lipid internal standards and displayed superior extracting power for major endogenous lipid classes. A total of 674 unique metabolites with a wide polarity range were annotated in CSF using, combining RPLC-MS/MS lipidomics (n = 219), HILIC-MS/MS (n = 304), and GC-quadrupole time of flight (QTOF) MS (n = 151). Overall, our findings show that the aB&D extraction method provided suitable lipid coverage, reproducibility, and extraction efficiency for global lipidomics profiling of human CSF samples. In combination with RPLC-MS/MS lipidomics, complementary screening approaches enabled a comprehensive metabolite signature that can be employed in an array of clinical studies.

Minimal information for studies of extracellular vesicles (MISEV2023): From basic to advanced approaches

Extracellular vesicles (EVs), through their complex cargo, can reflect the state of their cell of origin and change the functions and phenotypes of other cells. These features indicate strong biomarker and therapeutic potential and have generated broad interest, as evidenced by the steady year-on-year increase in the numbers of scientific publications about EVs. Important advances have been made in EV metrology and in understanding and applying EV biology. However, hurdles remain to realising the potential of EVs in domains ranging from basic biology to clinical applications due to challenges in EV nomenclature, separation from non-vesicular extracellular particles, characterisation and functional studies. To address the challenges and opportunities in this rapidly evolving field, the International Society for Extracellular Vesicles (ISEV) updates its 'Minimal Information for Studies of Extracellular Vesicles', which was first published in 2014 and then in 2018 as MISEV2014 and MISEV2018, respectively. The goal of the current document, MISEV2023, is to provide researchers with an updated snapshot of available approaches and their advantages and limitations for production, separation and characterisation of EVs from multiple sources, including cell culture, body fluids and solid tissues. In addition to presenting the latest state of the art in basic principles of EV research, this document also covers advanced techniques and approaches that are currently expanding the boundaries of the field. MISEV2023 also includes new sections on EV release and uptake and a brief discussion of in vivo approaches to study EVs. Compiling feedback from ISEV expert task forces and more than 1000 researchers, this document conveys the current state of EV research to facilitate robust scientific discoveries and move the field forward even more rapidly.

Risk Factors in Administering Spinal Anesthesia: A Comprehensive Review

Numerous advantages, including a quick start and consistent anesthesia, are provided by spinal anesthesia, a method often utilized in contemporary medicine for various surgical operations. However, it has some hazards, just like any medical procedure. With an emphasis on identifying and assessing the risk factors associated with administering spinal anesthesia, the review analyzes published literature and clinical investigations carried out in the field of anesthesia. Various key factors, including technique-related procedural and patient-related aspects, can influence the effectiveness of spinal anesthesia. Among these factors are age, sex, body mass index, concurrent conditions (such as cardiovascular disease, diabetes, and respiratory problems), pre-existing neurological issues, allergies, and a history of adverse responses to anesthesia drugs. Additionally, the chance of problems might be increased by physical abnormalities or malformations in the spinal canal and vertebral column. The safety and effectiveness of spinal anesthesia depend significantly on procedural factors, such as the type and dosage of anesthesia agents administered and the patient's position and alignment maintained during the entire surgical procedure and the injection rate. Increased risks can also be caused by inadequate monitoring and a slow response to unfavorable circumstances. Risk factors related to the technique include the expertise and competency of the anesthesiologist or medical professional carrying out the procedure. Inadequate post-procedure monitoring, inadvertent dural puncture, and improper needle placement might lead to complications during or after the spinal anesthesia administration. This review emphasizes the need for a complete preoperative assessment, suitable patient selection, and rigorous procedural planning to reduce the likelihood of problems during the administration of spinal anesthesia. It also emphasizes the significance of ongoing monitoring and timely management of adverse events to guarantee patient safety and the best results. Healthcare professionals may put preventative measures in place and follow best practices to limit possible consequences efficiently by recognizing the risk factors associated with spinal anesthesia. This review helps encourage safer anesthesia practices and improve patient care as medical knowledge and technology advance. However, further study and evidence-based recommendations are required to enhance patient outcomes and risk assessment.

Strategies for Drug Delivery into the Brain: A Review on Adenosine Receptors Modulation for Central Nervous System Diseases Therapy

The blood-brain barrier (BBB) is a biological barrier that protects the central nervous system (CNS) by ensuring an appropriate microenvironment. Brain microvascular endothelial cells (ECs) control the passage of molecules from blood to brain tissue and regulate their concentration-versus-time profiles to guarantee proper neuronal activity, angiogenesis and neurogenesis, as well as to prevent the entry of immune cells into the brain. However, the BBB also restricts the penetration of drugs, thus presenting a challenge in the development of therapeutics for CNS diseases. On the other hand, adenosine, an endogenous purine-based nucleoside that is expressed in most body tissues, regulates different body functions by acting through its G-protein-coupled receptors (A1, A2A, A2B and A3). Adenosine receptors (ARs) are thus considered potential drug targets for treating different metabolic, inflammatory and neurological diseases. In the CNS, A1 and A2A are expressed by astrocytes, oligodendrocytes, neurons, immune cells and ECs. Moreover, adenosine, by acting locally through its receptors A1 and/or A2A, may modulate BBB permeability, and this effect is potentiated when both receptors are simultaneously activated. This review showcases in vivo and in vitro evidence supporting AR signaling as a candidate for modifying endothelial barrier permeability in the treatment of CNS disorders.