Cerebrospinal Fluid Collection Research Articles

Metagenomic next-generation sequencing of cerebrospinal fluid reveals etiological and microbiological features in patients with various central nervous system infections.

The application of metagenomic next-generation sequencing (mNGS) in pathogens detection of cerebrospinal fluid (CSF) is limited because clinical, microbiological, and biological information are not well connected. We analyzed the 428 enrolled patients' clinical features, pathogens diagnostic efficiency of mNGS in CSF, microbial community structure and composition in CSF, and correlation of microbial and clinical biomarkers in CSF. General characteristics were unspecific but helpful in formulating a differential diagnosis. CSF mNGS has a higher detection rate (34.6%) compared to traditional methods (5.4%). mNGS detection rate was higher when the time from onset to CSF collection was ≤20 days, the CSF leukocytes count was >200 × 106/L, the CSF protein concentration was >1.3 g/L, or CSF glucose concentration was ≤2.5 mmol/L in non-postoperative bacterial CNS infections (CNSi). CSF was not strictly a sterile environment, and the potential pathogens may contribute to the dysbiosis of CSF microbiome. Furthermore, clinical biomarkers were significantly relevant to CNS pathogens. Clinical data are helpful in choosing a proper opportunity to obtain an accurate result of mNGS, and can speculate whether the mNGS results are correct or not. Our study is a pioneering study exploring the CSF microbiome in different CNSIs.

A cautionary tale of pseudo-Cryptococcus infection in neonates.

We report a tale of two cases of neonates, where India Ink preparation of cerebrospinal fluid (CSF) received in glass vials was suggestive of Cryptococcus; however, the absence of correlation and report of cases sequentially from the same unit raised alarm bells. Repeat smears using routine in-house and newly prepared stains were prepared and repeat sampling was collected in a strictly sterile specimen container, which resulted in negative microscopy for repeat samples (uncentrifuged and centrifuged). The source of contamination was found to be non-sterile glass vials used for CSF collection. This report underlines the requisite to maintain an aseptic chain from sample collection to processing, to prevent reporting of pseudo-infections that can upset diagnostic accuracy, especially when the aseptic chain has not been maintained.

Circulating Liquid Biopsy Biomarkers in Glioblastoma: Advances and Challenges.

Gliomas, particularly glioblastoma (GBM), represent the most prevalent and aggressive tumors of the central nervous system (CNS). Despite recent treatment advancements, patient survival rates remain low. The diagnosis of GBM traditionally relies on neuroimaging methods such as magnetic resonance imaging (MRI) or computed tomography (CT) scans and postoperative confirmation via histopathological and molecular analysis. Imaging techniques struggle to differentiate between tumor progression and treatment-related changes, leading to potential misinterpretation and treatment delays. Similarly, tissue biopsies, while informative, are invasive and not suitable for monitoring ongoing treatments. These challenges have led to the emergence of liquid biopsy, particularly through blood samples, as a promising alternative for GBM diagnosis and monitoring. Presently, blood and cerebrospinal fluid (CSF) sampling offers a minimally invasive means of obtaining tumor-related information to guide therapy. The idea that blood or any biofluid tests can be used to screen many cancer types has huge potential. Tumors release various components into the bloodstream or other biofluids, including cell-free nucleic acids such as microRNAs (miRNAs), circulating tumor DNA (ctDNA), circulating tumor cells (CTCs), proteins, extracellular vesicles (EVs) or exosomes, metabolites, and other factors. These factors have been shown to cross the blood-brain barrier (BBB), presenting an opportunity for the minimally invasive monitoring of GBM as well as for the real-time assessment of distinct genetic, epigenetic, transcriptomic, proteomic, and metabolomic changes associated with brain tumors. Despite their potential, the clinical utility of liquid biopsy-based circulating biomarkers is somewhat constrained by limitations such as the absence of standardized methodologies for blood or CSF collection, analyte extraction, analysis methods, and small cohort sizes. Additionally, tissue biopsies offer more precise insights into tumor morphology and the microenvironment. Therefore, the objective of a liquid biopsy should be to complement and enhance the diagnostic accuracy and monitoring of GBM patients by providing additional information alongside traditional tissue biopsies. Moreover, utilizing a combination of diverse biomarker types may enhance clinical effectiveness compared to solely relying on one biomarker category, potentially improving diagnostic sensitivity and specificity and addressing some of the existing limitations associated with liquid biomarkers for GBM. This review presents an overview of the latest research on circulating biomarkers found in GBM blood or CSF samples, discusses their potential as diagnostic, predictive, and prognostic indicators, and discusses associated challenges and future perspectives.

Evaluation of core Biomarkers of Alzheimer’s disease in saliva and plasma measured by chemiluminescent enzyme immunoassays on a fully automated platform

Cerebrospinal fluid (CSF) core biomarkers of Alzheimer’s disease (AD), including amyloid peptide beta-42 (Aβ42), Aβ42/40 ratio, and phosphorylated tau (pTau), are precious tools for supporting AD diagnosis. However, their use in clinical practice is limited due to the invasiveness of CSF collection. Thus, there is intensive research to find alternative, noninvasive, and widely accessible biological matrices to measure AD core biomarkers. In this study, we measured AD core biomarkers in saliva and plasma by a fully automated platform. We enrolled all consecutive patients with cognitive decline. For each patient, we measured Aβ42, Aβ40, and pTau levels in CSF, saliva, and plasma by Lumipulse G1200 (Fujirebio). We included forty-two patients, of whom 27 had AD. Levels of all biomarkers significantly differed in the three biofluids, with saliva having the lowest and CSF the highest levels of Aβ42, Aβ40, and pTau. A positive correlation of pTau, Aβ42/40 ratio, and pTau/Aβ42 ratio levels in CSF and plasma was detected, while no correlation between any biomarker in CSF and saliva was found. Our findings suggest that plasma but not saliva could represent a surrogate biofluid for measuring core AD biomarkers. Specifically, plasma Aβ42/40 ratio, pTau/Aβ42 ratio, and pTau could serve as surrogates of the corresponding CSF biomarkers.

Utility of circulating tumor DNA (ctDNA) from cerebrospinal fluid (CSF) for prognosis of patients with recurrent high grade glioma.

2010 Background: High-Grade Gliomas (HGGs) are the most aggressive primary brain tumors in adults and molecular characterization is crucial for diagnosis and optimal disease treatment. Due to the eloquent location of many HGGs, upfront or repeat tumor sampling may be sub-optimal. Hence, there is an urgent need to develop alternative, minimally invasive means to obtain diagnostic information and determine the expected clinical behavior. Here we report that circulating tumor DNA (ctDNA) from cerebrospinal fluid (CSF) can be used to identify disease defining genomic alterations and to track clonal evolution. Additionally, we demonstrate that detection of CSF ctDNA is positively correlated with leptomeningeal disease and overall survival suggesting that CSF ctDNA should be integrated into clinical decision making in the clinic. Methods: Our study includes 313 samples from 253 patients with recurrent glioma treated at Memorial Sloan Kettering Cancer Center who underwent CSF collection for routine clinical care and were sequenced using the MSK-IMPACT targeted clinical sequencing assay (468 and 505 genes). Alterations were classified as oncogenic based on OncoKB. 17% of genomic alterations detected were identified using a secondary bioinformatics analysis, following an informed approach with less stringent mutation calling criteria and Gaussian Mixture Model to call copy number events. CSF ctDNA positivity was determined by the presence of at least one oncogenic disease defining alteration or any shared alteration with the tumor. Results: Within this cohort, we found 193 CSF ctDNA positive (62%) and 120 CSF negative (38%) samples. Of note, CSF ctDNA positivity was the highest amongst histone mutant tumors with 94% CSF ctDNA positivity compared to 56% CSF ctDNA positivity for IDH-WT tumors. We noticed 44% of alterations shared between the tumor and the CSF, additionally, we noted considerable tumor evolution particularly within the growth signaling pathways (e.g. PDGFRA). The majority of the shared alterations were clonal, and we noticed the emergence of new clonal events in the CSF. Conclusions: Our cohort demonstrated that patients with positive CSF ctDNA had a significantly shorter overall survival compared to those who were CSF ctDNA negative (4.83 months vs 11.83 months, HR 2.1, p < 0.001). In tandem with secondary clinical analysis, radiographic findings also correlated with CSF ctDNA positivity. Specifically, the presence of enhancing disease and contact of the tumor with the ventricular space were positively associated with detection of CSF ctDNA. Additionally, CSF ctDNA was associated with positive cytology in 21/21 cases (100%). With our improved bioinformatics pipeline, we hypothesize ctDNA from CSF may be used as a prognostic biomarker for survival, but confirmation requires further validation in a prospective study.

Prevalence of detectable HIV-DNA and HIV-RNA in cerebrospinal fluid of youth with perinatal HIV and impaired cognition on antiretroviral therapy.

Central nervous system (CNS) HIV infection can impact cognition and may be an obstacle to cure in adolescents and young adults with perinatal HIV (AYAPHIV). IMPAACT2015 enrolled AYAPHIV on suppressive antiretroviral therapy (ART) with cognitive impairment to detect and quantify HIV in blood and cerebrospinal fluid (CSF). IMPAACT2015 was a U.S.-based multi-site, exploratory, observational study. Cognitive impairment was defined as NIH Toolbox Fluid Cognition Composite score (FCCS) more than 1 standard deviation below age-adjusted normative group mean. Cell-free HIV-RNA and cell-associated HIV pol/gag -DNA and 10 biomarkers of inflammation/neuronal injury were measured in paired CSF and blood. ART exposure concentrations were quantified in hair. Among 24 participants, 20 had successful CSF collection and 18 also met viral suppression criteria. Nine of 18 (50%) were female sex-at-birth, and 14 of 18 (78%) were black. Median (range) age was 20 years (13-27), time on ART was 18.3 years (8.0-25.5), and FCCS was 68 (53-80). HIV-DNA was detected in PBMCs from all participants. In CSF, two of 18 (11%, 95% CI: 1.4-34.7%) participants had detectable cell-free HIV-RNA, while HIV gag or pol -DNA was detectable in 13 of 18 (72%, 95% confidence interval: 47-90). Detectable HIV-DNA in CSF was associated with male sex-at-birth ( P = 0.051), lower CD4 + cell count at enrollment ( P = 0.016), and higher PBMC HIV pol -DNA copies ( P = 0.058). Hair antiretroviral concentrations and biomarkers were not associated with CSF HIV-DNA detection. We found that a high proportion of AYAPHIV with neurocognitive impairment had CSF cells harboring HIV-DNA during long-term virologic suppression. This evidence of persistent HIV-DNA in CSF suggests that the CNS should be considered in treatment and cure studies.

Spontaneous regression of an interhemispheric arachnoid cyst: illustrative case

BackgroundIntracranial arachnoid cysts are benign collections of cerebrospinal fluid that are often asymptomatic and discovered incidentally. An interhemispheric location of these lesions is rare, with only a few such cases reported in the literature. Though spontaneous regression of arachnoid cysts has been described in other locations, to date this phenomenon has not been reported in interhemispheric fissure cysts.ObservationsIn this report, we describe a patient with a large, multiloculated interhemispheric arachnoid cyst diagnosed on prenatal ultrasound. She did not exhibit neurologic deficits or signs of increased intracranial pressure and was observed with serial imaging. After several years of observation, imaging revealed spontaneous and progressive decrease in the cyst size.LessonsWe illustrate a case of regression of an interhemispheric arachnoid cyst in a pediatric patient. To our knowledge, this is the first reported case of spontaneous shrinkage of an arachnoid cyst in this location. Although the current presentation is rare, this reporting adds to the current understanding of natural history of arachnoid cysts and provides an example of radiographical improvement without intervention of a cyst located within the interhemispheric fissure.

132 Optimizing Success Rates of CSF Liquid Biopsy Examined With Next Generation Sequencing in Pediatric Central Nervous System Tumors

INTRODUCTION: Cerebrospinal fluid (CSF) liquid biopsy presents an attractive option for minimally invasive diagnosis and follow up for pediatric brain tumors. Best practice for obtaining appropriate cfDNA for next generation sequencing (NGS) is not currently known. METHODS: CSF was collected from patients under a prospective study to evaluate diagnostic utility of NGS. Samples were collected from control (non-tumor) and CNS tumor patients. CSF was collected at the dura opening, immediate ventricular catheter (IVC) from CSF divergent procedures, or ventricular shunt taps. Data was gathered on demographics, pathological diagnosis, tumor location, volume of CSF extraction, and DNA yield. RESULTS: CSF was extracted from 72 CNS tumor patients and 20 controls (48 female, 44 male). Of the CNS tumors, there were forty low-grade tumors (40/72) and thirty-two high-grade tumors (32/72). CSF collection location included dura opening (57), ventricular catheter (23), and shunt taps (12). cfDNA yield (ng) for CNS tumors displayed a mean of 135.5 ng (±353.4) and controls displayed a mean of 95.6 ng (±241.0). CNS tumor patients generated a significantly higher (p < 0.0001) DNA concentration (ng/cc) with a mean of 18.9 ng/cc (±82.7) compared to 0.5 ng/cc (±0.7) mean for controls. High grade tumors demonstrated a significantly greater amount of cfDNA concentration with a mean of 33.6 ng/cc (±116.6) whereas low grade tumors had a mean of 4.2 ng/cc (±5.0). CSF acquisition was 90.2% successful for NGS with a mean volume of 4.9 cc. In addition, infratentorial tumors revealed a 96% success rate with a mean volume of 5 cc. CONCLUSIONS: Extracting 4.9 cc of CSF had an 90.2% success rate for NGS. CSF may be acquired from either ventricular catheter or dura opening. High grade tumors had significantly higher cfDNA yield and concentration in CSF compared to low grade.

Abstract 3703: Utility of circulating tumor DNA (ctDNA) from cerebrospinal fluid (CSF) for prognosis of patients with recurrent high grade glioma

Abstract High-Grade Gliomas (HGGs) are the most aggressive primary brain tumors in adults and molecular characterization is crucial for diagnosis and optimal disease treatment. Due to the eloquent location of many HGGs, upfront or repeat tumor sampling may be sub-optimal. Hence, there is an urgent need to develop alternative, minimally-invasive means to obtain diagnostic information and determine the expected clinical behavior. Here we report that circulating tumor DNA (ctDNA) from cerebrospinal fluid (CSF) can be used to identify disease defining genomic alterations and to track clonal evolution. Additionally, we demonstrate that detection of CSF ctDNA is positively correlated with leptomeningeal disease and overall survival suggesting that CSF ctDNA should be integrated into clinical decision making in the clinic. Our study includes 315 samples from 254 patients with recurrent glioma treated at Memorial Sloan Kettering Cancer Center who underwent CSF collection for routine clinical care and were sequenced using the MSK-IMPACT targeted clinical sequencing assay (468 and 505 genes). Alterations were classified as oncogenic based on OncoKB. 23% of genomic alterations detected were identified using a secondary bioinformatics analysis, following an informed approach with less stringent mutation calling criteria and Gaussian Mixture Model to call copy number events. CSF ctDNA positivity was determined by the presence of at least one oncogenic disease defining alteration or any shared alteration with the tumor. Within this cohort, we found 198 CSF ctDNA positive (63%) and 117 CSF negative (37%) samples. Of note, CSF ctDNA positivity was the highest amongst histone mutant tumors with 94% CSF ctDNA positivity compared to 56% CSF ctDNA positivity for IDH-WT tumors. We noticed considerable evolution of the cancer genome in patients with sequential biopsies with only 35% of alterations shared between the tumor and the CSF, in particular within the growth signaling pathways (e.g. PDGFRA). The majority of the shared alterations were clonal, and we noticed the emergence of new clonal events in the CSF. Our cohort demonstrated that patients with positive CSF ctDNA had a significantly shorter overall survival compared to those who were CSF ctDNA negative (4.83 months vs 11.83 months, HR 2.1, p < 0.001). In tandem with secondary clinical analysis, radiographic findings also correlated with CSF ctDNA positivity. Specifically, the presence of enhancing disease and contact of the tumor with the ventricular space were positively associated with detection of CSF ctDNA. Additionally, CSF ctDNA was associated with positive cytology in 21/21 cases (100%). With our improved bioinformatics pipeline we hypothesize ctDNA from CSF may be used as a prognostic biomarker for survival, but confirmation requires further validation in a prospective study. Citation Format: Bridget M. Holle, Subhiksha Nandakumar, Christoph Kreitzer, Timothy Song, Marlene Tartaro, Charli Ann J. Hertz, Johnathan Rafailov, Carl Campos, Anne S. Reiner, Robert Young, Alicia Meng, Luca Pasquini, A. Rose Brannon, Nicholas D. Socci, Maria E. Arcila, David B. Solit, Michael F. Berger, Nikolaus Schultz, Ingo K. Mellinghoff, Alexandra M. Miller. Utility of circulating tumor DNA (ctDNA) from cerebrospinal fluid (CSF) for prognosis of patients with recurrent high grade glioma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 3703.

Disease staging of Alzheimer’s disease using a CSF-based biomarker model

Biological staging of individuals with Alzheimer’s disease (AD) may improve diagnostic and prognostic workup of dementia in clinical practice and the design of clinical trials. In this study, we used the Subtype and Stage Inference (SuStaIn) algorithm to establish a robust biological staging model for AD using cerebrospinal fluid (CSF) biomarkers. Our analysis involved 426 participants from BioFINDER-2 and was validated in 222 participants from the Knight Alzheimer Disease Research Center cohort. SuStaIn identified a singular biomarker sequence and revealed that five CSF biomarkers effectively constituted a reliable staging model (ordered: Aβ42/40, pT217/T217, pT205/T205, MTBR-tau243 and non-phosphorylated mid-region tau). The CSF stages (0–5) demonstrated a correlation with increased abnormalities in other AD-related biomarkers, such as Aβ-PET and tau-PET, and aligned with longitudinal biomarker changes reflective of AD progression. Higher CSF stages at baseline were associated with an elevated hazard ratio of clinical decline. This study highlights a common molecular pathway underlying AD pathophysiology across all patients, suggesting that a single CSF collection can accurately indicate the presence of AD pathologies and characterize the stage of disease progression. The proposed staging model has implications for enhancing diagnostic and prognostic assessments in both clinical practice and the design of clinical trials.

Association between clinical characteristics, acute steroid treatment and oligoclonal bands result in multiple sclerosis: A retrospective study

BackgroundDetection of oligoclonal bands (OCBs) in the cerebrospinal fluid (CSF) is important for diagnosis of multiple sclerosis (MS). Previous studies reported that treatment with intravenous methylprednisolone (IVMP) before lumber puncture (LP) could suppress OCBs production. The aim of this study was to assess whether IVMP initiation prior to CSF collection affects OCBs results in patients with an acute demyelinating event. Additionally, we examined which clinical characteristics are associated with the presence of OCBs in the CSF. MethodsWe retrospectively evaluated patients admitted to the neurology department at rabin medical center (RMC) between 2010 and 2022 who underwent LP with OCBs analysis as part of their demyelinating attack workup. Patients were divided into OCB-positive and OCB-negative groups and demographical and clinical characteristics (including timing and duration of acute steroid treatment and history of prior demyelinating attacks) were analyzed for association with OCBs results. ResultsA total of 342 patients were included with a median age of 35 years (IQR, 27–46). Two hundred thirty-eight (69.6 %) were OCB-positive. Initiation of IVMP before LP was not associated with negative OCBs (11.8 % Vs. 13.5 %, P = 0.721), nor was it correlated with OCBs positivity (OR=0.86, P = 0.66). CSF cell count was higher in OCB-positive patients (5 Vs. 3, P = 0.001), and a history of prior demyelinating attacks was associated with- (33.6 % Vs. 20.2 %, P = 0.014) and predictive of OCBs positivity (OR=2, P = 0.013). ConclusionsTiming of steroids was not associated with OCB positivity. However, pleocytosis and a prior attack were associated with OCB positivity in this cohort. Our results suggest that steroid treatment is unlikely to affect OCBs results. Ideally, larger prospective studies would be needed to confirm our observations.

Prenatal delta-9-tetrahydrocannabinol exposure alters fetal neurodevelopment in rhesus macaques

Prenatal cannabis use is associated with adverse offspring neurodevelopmental outcomes, however the underlying mechanisms are relatively unknown. We sought to determine the impact of chronic delta-9-tetrahydrocannabinol (THC) exposure on fetal neurodevelopment in a rhesus macaque model using advanced imaging combined with molecular and tissue studies. Animals were divided into two groups, control (n = 5) and THC-exposed (n = 5), which received a daily THC edible pre-conception and throughout pregnancy. Fetal T2-weighted MRI was performed at gestational days 85 (G85), G110, G135 and G155 to assess volumetric brain development. At G155, animals underwent cesarean delivery with collection of fetal cerebrospinal fluid (CSF) for microRNA (miRNA) studies and fetal tissue for histologic analysis. THC exposure was associated with significant age by sex interactions in brain growth, and differences in fetal brain histology suggestive of brain dysregulation. Two extracellular vesicle associated-miRNAs were identified in THC-exposed fetal CSF; pathway analysis suggests that these miRNAs are associated with dysregulated axonal guidance and netrin signaling. This data is indicative of subtle molecular changes consistent with the observed histological data, suggesting a potential role for fetal miRNA regulation by THC. Further studies are needed to determine whether these adverse findings correlate with long-term offspring neurodevelopmental health.

Plasma Biomarkers as Predictors of Progression to Dementia in Individuals with Mild Cognitive Impairment.

Blood-based biomarkers (BBMs) are of growing interest in the field of Alzheimer's disease (AD) and related dementias. This study aimed to assess the ability of plasma biomarkers to 1) predict disease progression from mild cognitive impairment (MCI) to dementia and 2) improve the predictive ability of magnetic resonance imaging (MRI) and cerebrospinal fluid (CSF) measures when combined. We used data from the Alzheimer's Disease Neuroimaging Initiative. Machine learning models were trained using the data from participants who remained cognitively stable (CN-s) and with Dementia diagnosis at 2-year follow-up visit. The models were used to predict progression to dementia in MCI individuals. We assessed the performance of models with plasma biomarkers against those with CSF and MRI measures, and also in combination with them. Our models with plasma biomarkers classified CN-s individuals from AD with an AUC of 0.75±0.03 and could predict conversion to dementia in MCI individuals with an AUC of 0.64±0.03 (17.1% BP, base prevalence). Models with plasma biomarkers performed better when combined with CSF and MRI measures (CN versus AD: AUC of 0.89±0.02; MCI-to-AD: AUC of 0.76±0.03, 21.5% BP). Our results highlight the potential of plasma biomarkers in predicting conversion to dementia in MCI individuals. While plasma biomarkers could improve the predictive ability of CSF and MRI measures when combined, they also show the potential to predict non-progression to AD when considered alone. The predictive ability of plasma biomarkers is crucially linked to reducing the costly and effortful collection of CSF and MRI measures.

Comparison of atlantoaxial and lumbosacral cerebrospinal fluid centesis techniques in South American camelids.

Iatrogenic blood contamination during cerebrospinal fluid (CSF) centesis is common, which can limit the diagnostic usefulness of the sample. A novel ultrasound-guided CSF collection technique is described in horses, by which CSF is obtained from the atlantoaxial (AA) space. To compare ultrasound-guided AA centesis with lumbosacral (LS) centesis in South American camelids (SAC). The hypotheses were that AA centesis would yield samples with less blood contamination although being technically more challenging than LS centesis. Eight clinically healthy adult SAC from a university-owned teaching herd. Single-blinded, randomized, 4-way, 4-period crossover study in which 2 veterinarians each performed both centesis techniques on each animal once. Cytological sample analysis was performed, and the technical difficulty of sample acquisition was assessed. The CSF was collected successfully and without complications by either technique during all collection attempts. Aspects of technical difficulty and concentrations of CSF analytes did not vary significantly between techniques. Median total nucleated cell and red blood cell counts were 1/μL and 0.5/μL and 167.5/μL and 155/μL for AA and LS techniques, respectively. The median total protein concentration was 32.9 mg/dL and 38 mg/dL for AA and LS centeses. A median of 1 attempt was necessary for both centesis techniques and the median number of needle repositioning events was 1 for AA and 0 for LS. Depending on clinical circumstances, ultrasound-guided AA centesis appears to be an acceptable alternative to other techniques for collection of CSF from SAC.

Timing of Biomarker Changes in Sporadic Alzheimer's Disease in Estimated Years from Symptom Onset.

A clock relating amyloid positron emission tomography (PET) to time was used to estimate the timing of biomarker changes in sporadic Alzheimer disease (AD). Research participants were included who underwent cerebrospinal fluid (CSF) collection within 2 years of amyloid PET. The ages at amyloid onset and AD symptom onset were estimated for each individual. The timing of change for plasma, CSF, imaging, and cognitive measures was calculated by comparing restricted cubic splines of cross-sectional data from the amyloid PET positive and negative groups. The amyloid PET positive sub-cohort (n = 118) had an average age of 70.4 ± 7.4 years (mean ± standard deviation) and 16% were cognitively impaired. The amyloid PET negative sub-cohort (n = 277) included individuals with low levels of amyloid plaque burden at all scans who were cognitively unimpaired at the time of the scans. Biomarker changes were detected 15-19 years before estimated symptom onset for CSF Aβ42/Aβ40, plasma Aβ42/Aβ40, CSF pT217/T217, and amyloid PET; 12-14 years before estimated symptom onset for plasma pT217/T217, CSF neurogranin, CSF SNAP-25, CSF sTREM2, plasma GFAP, and plasma NfL; and 7-9 years before estimated symptom onset for CSF pT205/T205, CSF YKL-40, hippocampal volumes, and cognitive measures. The use of an amyloid clock enabled visualization and analysis of biomarker changes as a function of estimated years from symptom onset in sporadic AD. This study demonstrates that estimated years from symptom onset based on an amyloid clock can be used as a continuous staging measure for sporadic AD and aligns with findings in autosomal dominant AD. ANN NEUROL 2024;95:951-965.

Modifiable dementia risk factors and AT(N) biomarkers: findings from the EPAD cohort.

Modifiable risk factors account for a substantial proportion of Alzheimer's disease (AD) cases and we currently have a discrete AT(N) biomarker profile for AD biomarkers: amyloid (A), p-tau (T), and neurodegeneration (N). Here, we investigated how modifiable risk factors relate to the three hallmark AT(N) biomarkers of AD. Participants from the European Prevention of Alzheimer's Dementia (EPAD) study underwent clinical assessments, brain magnetic resonance imaging, and cerebrospinal fluid collection and analysis. Generalized additive models (GAMs) with penalized regression splines were modeled in the AD Workbench on the NTKApp. A total of 1,434 participants were included (56% women, 39% APOE ε4+) with an average age of 65.5 (± 7.2) years. We found that modifiable risk factors of less education (t = 3.9, p < 0.001), less exercise (t = 2.1, p = 0.034), traumatic brain injury (t = -2.1, p = 0.036), and higher body mass index (t = -4.5, p < 0.001) were all significantly associated with higher AD biomarker burden. This cross-sectional study provides further support for modifiable risk factors displaying neuroprotective associations with the characteristic AT(N) biomarkers of AD.

The Use of Histoacryl Injections to Treat Subgaleal Cerebrospinal Fluid Collection After Cranioplasty

BACKGROUND AND OBJECTIVES: Cranioplasty is an important and basic operation in the neurosurgical field. An emergency craniectomy is performed to control malignant cerebral edema. If the patient survives, cranioplasty is performed to restore the skull defect; however, subgaleal cerebrospinal fluid collection (SCSFC) may occur. The authors aimed to identify risk factors for postoperative SCSFC and effective solutions with the subgaleal Histoacryl injection. METHODS: From January 2020 to December 2022, 154 craniectomies were performed at our hospital to relieve significant cerebral edema after traumatic brain injury; of these, 67 patients survived and underwent cranioplasty. Ten cases of postcranioplasty SCSFC were identified, among which 6 received subgaleal Histoacryl injection. RESULTS: Among the 10 SCSFC cases, 3 resolved with compression after cerebrospinal fluid aspiration, and 1 resolved after revision surgery and dural closure. Histoacryl injection was attempted for the other 6 patients. A single injection was sufficient for SCSFC resolution in 3 patients. One patient required 2 injections, and another required 3 injections. The remaining patient underwent epiduroperitoneal shunt surgery because of SCSFC persistence after 3 Histoacryl injections. Five of 6 patients (83.3%) showed an improvement of more than 80% after Histoacryl injection. CONCLUSION: Subgaleal Histoacryl injection is not considered a fundamental treatment for postoperative SCSFC but can be a successful alternative treatment.

Exploring small non-coding RNAs as blood-based biomarkers to predict Alzheimer’s disease

BackgroundAlzheimer’s disease (AD) diagnosis relies on clinical symptoms complemented with biological biomarkers, the Amyloid Tau Neurodegeneration (ATN) framework. Small non-coding RNA (sncRNA) in the blood have emerged as potential predictors of AD. We identified sncRNA signatures specific to ATN and AD, and evaluated both their contribution to improving AD conversion prediction beyond ATN alone.MethodsThis nested case–control study was conducted within the ACE cohort and included MCI patients matched by sex. Patients free of type 2 diabetes underwent cerebrospinal fluid (CSF) and plasma collection and were followed-up for a median of 2.45-years. Plasma sncRNAs were profiled using small RNA-sequencing. Conditional logistic and Cox regression analyses with elastic net penalties were performed to identify sncRNA signatures for A+(T|N)+ and AD. Weighted scores were computed using cross-validation, and the association of these scores with AD risk was assessed using multivariable Cox regression models. Gene ontology (GO) and Kyoto encyclopaedia of genes and genomes (KEGG) enrichment analysis of the identified signatures were performed.ResultsThe study sample consisted of 192 patients, including 96 A+(T|N)+ and 96 A-T-N- patients. We constructed a classification model based on a 6-miRNAs signature for ATN. The model could classify MCI patients into A-T-N- and A+(T|N)+ groups with an area under the curve of 0.7335 (95% CI, 0.7327 to 0.7342). However, the addition of the model to conventional risk factors did not improve the prediction of AD beyond the conventional model plus ATN status (C-statistic: 0.805 [95% CI, 0.758 to 0.852] compared to 0.829 [95% CI, 0.786, 0.872]). The AD-related 15-sncRNAs signature exhibited better predictive performance than the conventional model plus ATN status (C-statistic: 0.849 [95% CI, 0.808 to 0.890]). When ATN was included in this model, the prediction further improved to 0.875 (95% CI, 0.840 to 0.910). The miRNA-target interaction network and functional analysis, including GO and KEGG pathway enrichment analysis, suggested that the miRNAs in both signatures are involved in neuronal pathways associated with AD.ConclusionsThe AD-related sncRNA signature holds promise in predicting AD conversion, providing insights into early AD development and potential targets for prevention.

Recommendations for reproducibility of cerebrospinal fluid extracellular vesicle studies.

Cerebrospinal fluid (CSF) is a clear, transparent fluid derived from blood plasma that protects the brain and spinal cord against mechanical shock, provides buoyancy, clears metabolic waste and transports extracellular components to remote sites in the brain. Given its contact with the brain and the spinal cord, CSF is the most informative biofluid for studies of the central nervous system (CNS). In addition to other components, CSF contains extracellular vesicles (EVs) that carry bioactive cargoes (e.g., lipids, nucleic acids, proteins), and that can have biological functions within and beyond the CNS. Thus, CSF EVs likely serve as both mediators of and contributors to communication in the CNS. Accordingly, their potential as biomarkers for CNS diseases has stimulated much excitement for and attention to CSF EV research. However, studies on CSF EVs present unique challenges relative to EV studies in other biofluids, including the invasive nature of CSF collection, limited CSF volumes and the low numbers of EVs in CSF as compared to plasma. Here, the objectives of the International Society for Extracellular Vesicles CSF Task Force are to promote the reproducibility of CSF EV studies by providing current reporting and best practices, and recommendations and reporting guidelines, for CSF EV studies. To accomplish this, we created and distributed a world-wide survey to ISEV members to assess methods considered 'best practices' for CSF EVs, then performed a detailed literature review for CSF EV publications that was used to curate methods and resources. Based on responses to the survey and curated information from publications, the CSF Task Force herein provides recommendations and reporting guidelines to promote the reproducibility of CSF EV studies in seven domains: (i) CSF Collection, Processing, and Storage; (ii) CSF EV Separation/Concentration; (iii) CSF EV Size and Number Measurements; (iv) CSF EV Protein Studies; (v) CSF EV RNA Studies; (vi) CSF EV Omics Studies and (vii) CSF EV Functional Studies.

Dural and deep cervical musculature anesthetic blockade for atlantoaxial collection of cerebrospinal fluid in horses

The analysis of cerebrospinal fluid has diagnostic, prognostic, and therapeutic value in neurological illnesses in horses. There are different methods for obtaining cerebrospinal fluid, with the collection between the C1 and C2 vertebrae being a more recent methodology, which allows the procedure to be performed in standing patients, without the limitations of general anesthesia and with a low contamination of the sample with blood, presenting itself as a practical alternative. This study evaluated the efficacy and safety of a local dural blockade in healthy horses submitted to cerebrospinal fluid collection by atlantoaxial puncture and the quality of the samples obtained by this procedure, which were submitted to physical, chemical, and cytological analyses. The animals were evaluated considering aspects such as pain, sensitivity, the presence of edema, temperature variations, and ultrasonographic alterations post-collection. Discrete local changes were observed after the puncture, and the procedure was considered safe and simple to perform. Lidocaine blockade could reduce the reaction elicited by the needle passing through the dura mater, and the samples obtained showed satisfactory quality and laboratory results consistent with the values compiled in the literature. Transient hyperthermia was observed in 70% (7/10) of the animals in the dural blockade group, and 80%(8/10) of the patients from the control group, totalizing 75% of all individuals evaluated. The rectal temperature alteration was observed 4 to 12 hours after the procedure and was entirely resolved without intervention by the 24-hour evaluation.