Fluids and Barriers of the CNS最新文献

{"title":"Phase-contrast MRI analysis of cerebral blood and CSF flow dynamic interactions.","authors":"Kimi Piedad Owashi, Pan Liu, Serge Metanbou, Cyrille Capel, Olivier Balédent","doi":"10.1186/s12987-024-00578-w","DOIUrl":"10.1186/s12987-024-00578-w","url":null,"abstract":"<p><strong>Background: </strong>Following the Monro-Kellie doctrine, the Cerebral Blood Volume Changes (CB_VC) should be mirrored by the Cerebrospinal Fluid Volume Changes (CSF_VC) at the spinal canal. Cervical level is often chosen to estimate CB_VC during the cardiac cycle. However, due to the heterogeneity in the anatomy of extracranial internal jugular veins and their high compliance, we hypothesize that the intracranial level could be a better choice to investigate blood and cerebrospinal fluid (CSF) interactions. This study aims to determine which level, intracranial or extracranial, is more suitable for measuring arterial and venous flows to study cerebral blood and CSF dynamics interactions.</p><p><strong>Methods: </strong>The spinal CSF and cerebral blood flow measured at intracranial and extracranial levels were quantified using cine phase-contrast magnetic resonance imaging (PC-MRI) in 38 healthy young adults. Subsequently, CSF_VC and CB_VC were calculated, and by linear regression analysis (R² and slope), the relationship between CB_VC at both levels and the spinal CSF_VC was compared. The differences between extracranial and intracranial measurements were assessed using either a paired Student's t-test or Wilcoxon's test, depending on the normality of the data distribution.</p><p><strong>Results: </strong>The CB_VC amplitude was significantly higher at the extracranial level (0.89 ± 0.28 ml/CC) compared to the intracranial level (0.73 ± 0.19 ml/CC; p < 0.001). CSF oscillations through the spinal canal do not completely balance blood volume changes. The R² and the slope values obtained from the linear regression analysis between CSF and blood flows were significantly higher in magnitude for the intracranial CB_VC (R²: 0.82 ± 0.16; slope: - 0.74 ± 0.19) compared to the extracranial CB_VC (R²: 0.47 ± 0.37; slope: -0.36 ± 0.33; p < 0.001). Interestingly, extracranial CB_VC showed a greater variability compared to intracranial CB_VC.</p><p><strong>Conclusion: </strong>Our results confirmed that CSF does not completely and instantaneously balance cerebral blood expansion during the cardiac cycle. Nevertheless, the resting volume is very small compared to the total intracranial volume. To our knowledge, this study is the first to demonstrate these findings using cerebral blood flow measured intracranially below the Circle of Willis. Additionally, our findings show that cerebral arterial and venous flow dynamic measurements during the cardiac cycle obtained by PC-MRI at the intracranial plane strongly correlate with CSF oscillations measured in the spinal canal. Therefore, the intracranial vascular plane is more relevant for analyzing cerebral blood and CSF interactions during the cardiac cycle compared to measurements taken at the cervical vascular level.</p>","PeriodicalId":12321,"journal":{"name":"Fluids and Barriers of the CNS","volume":"21 1","pages":"88"},"PeriodicalIF":5.9,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11514974/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142521508","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"[¹¹C]Metoclopramide PET can detect a seizure-induced up-regulation of cerebral P-glycoprotein in epilepsy patients.","authors":"Myriam El Biali, Louise Breuil, Matthias Jackwerth, Severin Mairinger, Maria Weber, Michael Wölfl-Duchek, Karsten Bamminger, Ivo Rausch, Lukas Nics, Marcus Hacker, Sebastian Rodrigo, Viviane Bouilleret, Markus Zeitlinger, Ekaterina Pataraia, Nicolas Tournier, Martin Bauer, Oliver Langer","doi":"10.1186/s12987-024-00588-8","DOIUrl":"10.1186/s12987-024-00588-8","url":null,"abstract":"<p><strong>Background: </strong>P-glycoprotein (P-gp) is an efflux transporter which is abundantly expressed at the blood-brain barrier (BBB) and which has been implicated in the pathophysiology of various brain diseases. The radiolabelled antiemetic drug [¹¹C]metoclopramide is a P-gp substrate for positron emission tomography (PET) imaging of P-gp function at the BBB. To assess whether [¹¹C]metoclopramide can detect increased P-gp function in the human brain, we employed drug-resistant temporal lobe epilepsy (TLE) as a model disease with a well characterised, regional P-gp up-regulation at the BBB.</p><p><strong>Methods: </strong>Eight patients with drug-resistant (DRE) TLE, 5 seizure-free patients with drug-sensitive (DSE) focal epilepsy, and 15 healthy subjects underwent brain PET imaging with [¹¹C]metoclopramide on a fully-integrated PET/MRI system. Concurrent with PET, arterial blood sampling was performed to generate a metabolite-corrected arterial plasma input function for kinetic modelling. The choroid plexus was outmasked on the PET images to remove signal contamination from the neighbouring hippocampus. Using a brain atlas, 10 temporal lobe sub-regions were defined and analysed with a 1-tissue-2-rate constant compartmental model to estimate the rate constants for radiotracer transfer from plasma to brain (K₁) and from brain to plasma (k₂), and the total volume of distribution (V_T = K₁/k₂).</p><p><strong>Results: </strong>DRE patients but not DSE patients showed significantly higher k₂ values and a trend towards lower V_T values in several temporal lobe sub-regions located ipsilateral to the epileptic focus as compared to healthy subjects (k₂: hippocampus: +34%, anterior temporal lobe, medial part: +28%, superior temporal gyrus, posterior part: +21%).</p><p><strong>Conclusions: </strong>[¹¹C]Metoclopramide PET can detect a seizure-induced P-gp up-regulation in the epileptic brain. The efflux rate constant k₂ seems to be the most sensitive parameter to measure increased P-gp function with [¹¹C]metoclopramide. Our study provides evidence that disease-induced alterations in P-gp expression at the BBB can lead to changes in the distribution of a central nervous system-active drug to the human brain, which could affect the efficacy and/or safety of drugs. [¹¹C]Metoclopramide PET may be used to assess or predict the contribution of increased P-gp function to drug resistance and disease pathophysiology in various brain diseases.</p><p><strong>Trial registration: </strong>EudraCT 2019-003137-42. Registered 28 February 2020.</p>","PeriodicalId":12321,"journal":{"name":"Fluids and Barriers of the CNS","volume":"21 1","pages":"87"},"PeriodicalIF":5.9,"publicationDate":"2024-10-28","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11514750/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142497795","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Active CNS delivery of oxycodone in healthy and endotoxemic pigs.","authors":"Frida Bällgren, Tilda Bergfast, Aghavni Ginosyan, Jessica Mahajan, Miklós Lipcsey, Margareta Hammarlund-Udenaes, Stina Syvänen, Irena Loryan","doi":"10.1186/s12987-024-00583-z","DOIUrl":"10.1186/s12987-024-00583-z","url":null,"abstract":"<p><strong>Background: </strong>The primary objective of this study was to advance our understanding of active drug uptake at brain barriers in higher species than rodents, by examining oxycodone brain concentrations in pigs.</p><p><strong>Methods: </strong>This was investigated by a microdialysis study in healthy and endotoxemic conditions to increase the understanding of inter-species translation of putative proton-coupled organic cation (H⁺/OC) antiporter-mediated central nervous system (CNS) drug delivery in health and pathology, and facilitate the extrapolation to humans for improved CNS drug treatment in patients. Additionally, we sought to evaluate the efficacy of lumbar cerebrospinal fluid (CSF) exposure readout as a proxy for brain unbound interstitial fluid (ISF) concentrations. By simultaneously monitoring unbound concentrations in blood, the frontal cortical area, the lateral ventricle (LV), and the lumbar intrathecal space in healthy and lipopolysaccharide (LPS)-induced inflammation states within the same animal, we achieved exceptional spatiotemporal resolution in mapping oxycodone transport across CNS barriers.</p><p><strong>Results: </strong>Our findings provide novel evidence of higher unbound oxycodone concentrations in brain ISF compared to blood, yielding an unbound brain-to-plasma concentration ratio (K_p,uu,brain) of 2.5. This supports the hypothesis of the presence of the H⁺/OC antiporter system at the blood-brain barrier (BBB) in pigs. Despite significant physiological changes, reflected in pig Sequential Organ Failure Assessment, pSOFA scores, oxycodone blood concentrations and its active net uptake across the BBB remained nearly unchanged during three hours of i.v. infusion of 4 µg/kg/h LPS from Escherichia coli (O111:B4). Mean K_p,uu,LV values indicated active uptake also at the blood-CSF barrier in healthy and endotoxemic pigs. Lumbar CSF concentrations showed minimal inter-individual variability during the experiment, with a mean K_{p,uu,lumbarCSF} of 1.5. LPS challenge caused a slight decrease in K_p,uu,LV, while K_{p,uu,lumbarCSF} remained unaffected.</p><p><strong>Conclusions: </strong>This study enhances our understanding of oxycodone pharmacokinetics and CNS drug delivery in both healthy and inflamed conditions, providing crucial insights for translating these findings to clinical settings.</p>","PeriodicalId":12321,"journal":{"name":"Fluids and Barriers of the CNS","volume":"21 1","pages":"86"},"PeriodicalIF":5.9,"publicationDate":"2024-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11515623/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142497796","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Significant individual variation in cardiac-cycle-linked cerebrospinal fluid production following subarachnoid hemorrhage.","authors":"Per Kristian Eide, Ragnhild Marie Undseth, Øyvind Gjertsen, Lars Magnus Valnes, Geir Ringstad, Erika Kristina Lindstrøm","doi":"10.1186/s12987-024-00587-9","DOIUrl":"https://doi.org/10.1186/s12987-024-00587-9","url":null,"abstract":"<p><strong>Background: </strong>Spontaneous subarachnoid hemorrhage (SAH) often results in altered cerebrospinal fluid (CSF) flow and secondary hydrocephalus, yet the mechanisms behind these phenomena remain poorly understood. This study aimed to elucidate the impact of SAH on individual CSF flow patterns and their association with secondary hydrocephalus.</p><p><strong>Methods: </strong>In patients who had experienced SAH, changes in CSF flow were assessed using cardiac-gated phase-contrast magnetic resonance imaging (PC-MRI) at the Sylvian aqueduct and cranio-cervical junction (CCJ). Within these regions of interest, volumetric CSF flow was determined for every pixel and net CSF flow volume and direction calculated. The presence of acute or chronic hydrocephalus was deemed from ventriculomegaly and need of CSF diversion. For comparison, we included healthy subjects and patients examined for different CSF diseases.</p><p><strong>Results: </strong>Twenty-four SAH patients were enrolled, revealing a heterogeneous array of CSF flow alterations at the Sylvian aqueduct. The cardiac-cycle-linked CSF net flow in Sylvian aqueduct differed from the traditional figures of ventricular CSF production about 0.30-0.40 mL/min. In 15 out of 24 patients (62.5%), net CSF flow was retrograde from the fourth to the third and lateral ventricles, while it was upward at the cranio-cervical junction in 2 out of 2 patients (100%). The diverse CSF flow metrics did not distinguish between individuals with acute or chronic secondary hydrocephalus. In comparison, 4/4 healthy subjects showed antegrade net CSF flow in the Sylvian aqueduct and net upward CSF flow in CCJ. These net CSF flow measures also showed interindividual variability among other patients with CSF diseases.</p><p><strong>Conclusions: </strong>There is considerable inter-individual variation in net CSF flow rates following SAH. Net CSF flow in the Sylvian aqueduct differs markedly from the traditional ventricular CSF production rates of 0.30-0.40 mL/min in SAH patients, but less so in healthy subjects. Furthermore, the cardiac-cycle-linked net CSF flow rates in Sylvian aqueduct and CCJ suggest an important role of extra-ventricular CSF production.</p>","PeriodicalId":12321,"journal":{"name":"Fluids and Barriers of the CNS","volume":"21 1","pages":"85"},"PeriodicalIF":5.9,"publicationDate":"2024-10-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11495023/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142497797","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Elevated peripheral inflammation is associated with choroid plexus enlargement in independent sporadic amyotrophic lateral sclerosis cohorts.","authors":"Sujuan Sun, Yujing Chen, Yan Yun, Bing Zhao, Qingguo Ren, Xiaohan Sun, Xiangshui Meng, Chuanzhu Yan, Pengfei Lin, Shuangwu Liu","doi":"10.1186/s12987-024-00586-w","DOIUrl":"10.1186/s12987-024-00586-w","url":null,"abstract":"<p><strong>Background: </strong>Using neuroimaging techniques, growing evidence has suggested that the choroid plexus (CP) volume is enlarged in multiple neurodegenerative diseases, including amyotrophic lateral sclerosis (ALS). Notably, the CP has been suggested to play an important role in inflammation-induced CNS damage under disease conditions. However, to our knowledge, no study has investigated the relationships between peripheral inflammation and CP volume in sporadic ALS patients. Thus, in this study, we aimed to verify CP enlargement and explore its association with peripheral inflammation in vivo in independent ALS cohorts.</p><p><strong>Methods: </strong>Based on structural MRI data, CP volume was measured using Gaussian mixture models and further manually corrected in two independent cohorts of sporadic ALS patients and healthy controls (HCs). Serum inflammatory protein levels were measured using a novel high-sensitivity Olink proximity extension assay (PEA) technique. Xtreme gradient boosting (XGBoost) was used to explore the contribution of peripheral inflammatory factors to CP enlargement. Then, partial correlation analyses were performed.</p><p><strong>Results: </strong>CP volumes were significantly higher in ALS patients than in HCs in the independent cohorts. Compared with HCs, serum levels of CRP, IL-6, CXCL10, and 35 other inflammatory factors were significantly increased in ALS patients. Using the XGBoost approach, we established a model-based importance of features, and the top three predictors of CP volume in ALS patients were CRP, IL-6, and CXCL10 (with gains of 0.24, 0.18, and 0.15, respectively). Correlation analyses revealed that CRP, IL-6, and CXCL10 were significantly associated with CP volume in ALS patients (r = 0.462 ∼ 0.636, p < 0.001).</p><p><strong>Conclusion: </strong>Our study is the first to reveal a consistent and replicable contribution of peripheral inflammation to CP enlargement in vivo in sporadic ALS patients. Given that CP enlargement has been recently detected in other brain diseases, these findings should consider extending to other disease conditions with a peripheral inflammatory component.</p>","PeriodicalId":12321,"journal":{"name":"Fluids and Barriers of the CNS","volume":"21 1","pages":"83"},"PeriodicalIF":5.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11492712/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142461600","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Data-independent acquisition proteomic analysis of the brain microvasculature in Alzheimer's disease identifies major pathways of dysfunction and upregulation of cytoprotective responses.","authors":"Michelle A Erickson, Richard S Johnson, Mamatha Damodarasamy, Michael J MacCoss, C Dirk Keene, William A Banks, May J Reed","doi":"10.1186/s12987-024-00581-1","DOIUrl":"10.1186/s12987-024-00581-1","url":null,"abstract":"<p><p>Brain microvascular dysfunction is an important feature of Alzheimer's disease (AD). To better understand the brain microvascular molecular signatures of AD, we processed and analyzed isolated human brain microvessels by data-independent acquisition liquid chromatography with tandem mass spectrometry (DIA LC-MS/MS) to generate a quantitative dataset at the peptide and protein level. Brain microvessels were isolated from parietal cortex grey matter using protocols that preserve viability for downstream functional studies. Our cohort included 23 subjects with clinical and neuropathologic concordance for Alzheimer's disease, and 21 age-matched controls. In our analysis, we identified 168 proteins whose abundance was significantly increased, and no proteins that were significantly decreased in AD. The most highly increased proteins included amyloid beta, tau, midkine, SPARC related modular calcium binding 1 (SMOC1), and fatty acid binding protein 7 (FABP7). Additionally, Gene Ontology (GO) enrichment analysis identified the enrichment of increased proteins involved in cellular detoxification and antioxidative responses. A systematic evaluation of protein functions using the UniProt database identified groupings into common functional themes including the regulation of cellular proliferation, cellular differentiation and survival, inflammation, extracellular matrix, cell stress responses, metabolism, coagulation and heme breakdown, protein degradation, cytoskeleton, subcellular trafficking, cell motility, and cell signaling. This suggests that AD brain microvessels exist in a stressed state of increased energy demand, and mount a compensatory response to ongoing oxidative and cellular damage that is associated with AD. We also used public RNAseq databases to identify cell-type enriched genes that were detected at the protein level and found no changes in abundance of these proteins between control and AD groups, indicating that changes in cellular composition of the isolated microvessels were minimal between AD and no-AD groups. Using public data, we additionally found that under half of the proteins that were significantly increased in AD microvessels had concordant changes in brain microvascular mRNA, implying substantial discordance between gene and protein levels. Together, our results offer novel insights into the molecular underpinnings of brain microvascular dysfunction in AD.</p>","PeriodicalId":12321,"journal":{"name":"Fluids and Barriers of the CNS","volume":"21 1","pages":"84"},"PeriodicalIF":5.9,"publicationDate":"2024-10-21","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11492478/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142461599","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Oxidative stress alters mitochondrial homeostasis in isolated brain capillaries.","authors":"Gopal V Velmurugan, Hemendra J Vekaria, Anika M S Hartz, Björn Bauer, W Brad Hubbard","doi":"10.1186/s12987-024-00579-9","DOIUrl":"10.1186/s12987-024-00579-9","url":null,"abstract":"<p><strong>Background: </strong>Neurovascular deficits and blood-brain barrier (BBB) dysfunction are major hallmarks of brain trauma and neurodegenerative diseases. Oxidative stress is a prominent contributor to neurovascular unit (NVU) dysfunction and can propagate BBB disruption. Oxidative damage results in an imbalance of mitochondrial homeostasis, which can further drive functional impairment of brain capillaries. To this end, we developed a method to track mitochondrial-related changes after oxidative stress in the context of neurovascular pathophysiology as a critical endophenotype of neurodegenerative diseases.</p><p><strong>Methods: </strong>To study brain capillary-specific mitochondrial function and dynamics in response to oxidative stress, we developed an ex vivo model in which we used isolated brain capillaries from transgenic mice that express dendra2 green specifically in mitochondria (mtD2g). Isolated brain capillaries were incubated with 2,2'-azobis-2-methyl-propanimidamide dihydrochloride (AAPH) or hydrogen peroxide (H₂O₂) to induce oxidative stress through lipid peroxidation. Following the oxidative insult, mitochondrial bioenergetics were measured using the Seahorse XFe96 flux analyzer, and mitochondrial dynamics were measured using confocal microscopy with Imaris software.</p><p><strong>Results: </strong>We optimized brain capillary isolation with intact endothelial cell tight-junction and pericyte integrity. Further, we demonstrate consistency of the capillary isolation process and cellular enrichment of the isolated capillaries. Mitochondrial bioenergetics and morphology assessments were optimized in isolated brain capillaries. Finally, we found that oxidative stress significantly decreased mitochondrial respiration and altered mitochondrial morphology in brain capillaries, including mitochondrial volume and count.</p><p><strong>Conclusions: </strong>Following ex vivo isolation of brain capillaries, we confirmed the stability of mitochondrial parameters, demonstrating the feasibility of this newly developed platform. We also demonstrated that oxidative stress has profound effects on mitochondrial homeostasis in isolated brain capillaries. This novel method can be used to evaluate pharmacological interventions to target oxidative stress or mitochondrial dysfunction in cerebral small vessel disease and neurovascular pathophysiology as major players in neurodegenerative disease.</p>","PeriodicalId":12321,"journal":{"name":"Fluids and Barriers of the CNS","volume":"21 1","pages":"81"},"PeriodicalIF":5.9,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11476969/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142461613","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Modeling CSF circulation and the glymphatic system during infusion using subject specific intracranial pressures and brain geometries.","authors":"Lars Willas Dreyer, Anders Eklund, Marie E Rognes, Jan Malm, Sara Qvarlander, Karen-Helene Støverud, Kent-Andre Mardal, Vegard Vinje","doi":"10.1186/s12987-024-00582-0","DOIUrl":"https://doi.org/10.1186/s12987-024-00582-0","url":null,"abstract":"<p><strong>Background: </strong>Infusion testing is an established method for assessing CSF resistance in patients with idiopathic normal pressure hydrocephalus (iNPH). To what extent the increased resistance is related to the glymphatic system is an open question. Here we introduce a computational model that includes the glymphatic system and enables us to determine the importance of (1) brain geometry, (2) intracranial pressure, and (3) physiological parameters on the outcome of and response to an infusion test.</p><p><strong>Methods: </strong>We implemented a seven-compartment multiple network porous medium model with subject specific geometries from MR images using the finite element library FEniCS. The model consists of the arterial, capillary and venous blood vessels, their corresponding perivascular spaces, and the extracellular space (ECS). Both subject specific brain geometries and subject specific infusion tests were used in the modeling of both healthy adults and iNPH patients. Furthermore, we performed a systematic study of the effect of variations in model parameters.</p><p><strong>Results: </strong>Both the iNPH group and the control group reached a similar steady state solution when subject specific geometries under identical boundary conditions was used in simulation. The difference in terms of average fluid pressure and velocity between the iNPH and control groups, was found to be less than 6% during all stages of infusion in all compartments. With subject specific boundary conditions, the largest computed difference was a 75% greater fluid speed in the arterial perivascular space (PVS) in the iNPH group compared to the control group. Changes to material parameters changed fluid speeds by several orders of magnitude in some scenarios. A considerable amount of the CSF pass through the glymphatic pathway in our models during infusion, i.e., 28% and 38% in the healthy and iNPH patients, respectively.</p><p><strong>Conclusions: </strong>Using computational models, we have found the relative importance of subject specific geometries to be less important than individual differences in resistance as measured with infusion tests and model parameters such as permeability, in determining the computed pressure and flow during infusion. Model parameters are uncertain, but certain variations have large impact on the simulation results. The computations resulted in a considerable amount of the infused volume passing through the brain either through the perivascular spaces or the extracellular space.</p>","PeriodicalId":12321,"journal":{"name":"Fluids and Barriers of the CNS","volume":"21 1","pages":"82"},"PeriodicalIF":5.9,"publicationDate":"2024-10-15","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11481529/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142461612","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Ex vivo nanoscale abluminal mapping of putative cargo receptors at the blood-brain barrier of expanded brain capillaries.","authors":"Mikkel Roland Holst, Mette Richner, Pernille Olsgaard Arenshøj, Parvez Alam, Kathrine Hyldig, Morten Schallburg Nielsen","doi":"10.1186/s12987-024-00585-x","DOIUrl":"https://doi.org/10.1186/s12987-024-00585-x","url":null,"abstract":"<p><p>Receptor mediated transport of therapeutic antibodies through the blood-brain barrier (BBB) give promise for drug delivery to alleviate brain diseases. We developed a low-cost method to obtain nanoscale localization data of putative cargo receptors. We combine existing ex vivo isolation methods with expansion microscopy (ExM) to analyze receptor localizations in brain microcapillaries. Using this approach, we show how to analyze receptor localizations in endothelial cells of brain microcapillaries in relation to the abluminal marker collagen IV. By choosing the thinnest capillaries, microcapillaries for analysis, we ensure the validity of collagen IV as an abluminal marker. With this tool, we confirm transferrin receptors as well as sortilin to be both luminally and abluminally localized. Furthermore, we identify basigin to be an abluminal receptor. Our methodology can be adapted to analyze different types of isolated brain capillaries and we anticipate that this approach will be very useful for the research community to gain new insight into cargo receptor trafficking in the slim brain endothelial cells to elucidate novel paths for future drug design.</p>","PeriodicalId":12321,"journal":{"name":"Fluids and Barriers of the CNS","volume":"21 1","pages":"80"},"PeriodicalIF":5.9,"publicationDate":"2024-10-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11475543/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142461611","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"iPSC-derived blood-brain barrier modeling reveals APOE isoform-dependent interactions with amyloid beta.","authors":"Yunfeng Ding, Sean P Palecek, Eric V Shusta","doi":"10.1186/s12987-024-00580-2","DOIUrl":"10.1186/s12987-024-00580-2","url":null,"abstract":"<p><strong>Background: </strong>Three common isoforms of the apolipoprotein E (APOE) gene - APOE2, APOE3, and APOE4 - hold varying significance in Alzheimer's Disease (AD) risk. The APOE4 allele is the strongest known genetic risk factor for late-onset Alzheimer's Disease (AD), and its expression has been shown to correlate with increased central nervous system (CNS) amyloid deposition and accelerated neurodegeneration. Conversely, APOE2 is associated with reduced AD risk and lower CNS amyloid burden. Recent clinical data have suggested that increased blood-brain barrier (BBB) leakage is commonly observed among AD patients and APOE4 carriers. However, it remains unclear how different APOE isoforms may impact AD-related pathologies at the BBB.</p><p><strong>Methods: </strong>To explore potential impacts of APOE genotypes on BBB properties and BBB interactions with amyloid beta, we differentiated isogenic human induced pluripotent stem cell (iPSC) lines with different APOE genotypes into both brain microvascular endothelial cell-like cells (BMEC-like cells) and brain pericyte-like cells. We then compared the effect of different APOE isoforms on BBB-related and AD-related phenotypes. Statistical significance was determined via ANOVA with Tukey's post hoc testing as appropriate.</p><p><strong>Results: </strong>Isogenic BMEC-like cells with different APOE genotypes had similar trans-endothelial electrical resistance, tight junction integrity and efflux transporter gene expression. However, recombinant APOE4 protein significantly impeded the \"brain-to-blood\" amyloid beta 1-40 (Aβ40) transport capabilities of BMEC-like cells, suggesting a role in diminished amyloid clearance. Conversely, APOE2 increased amyloid beta 1-42 (Aβ42) transport in the model. Furthermore, we demonstrated that APOE-mediated amyloid transport by BMEC-like cells is dependent on LRP1 and p-glycoprotein pathways, mirroring in vivo findings. Pericyte-like cells exhibited similar APOE secretion levels across genotypes, yet APOE4 pericyte-like cells showed heightened extracellular amyloid deposition, while APOE2 pericyte-like cells displayed the least amyloid deposition, an observation in line with vascular pathologies in AD patients.</p><p><strong>Conclusions: </strong>While APOE genotype did not directly impact general BMEC or pericyte properties, APOE4 exacerbated amyloid clearance and deposition at the model BBB. Conversely, APOE2 demonstrated a potentially protective role by increasing amyloid transport and decreasing deposition. Our findings highlight that iPSC-derived BBB models can potentially capture amyloid pathologies at the BBB, motivating further development of such in vitro models in AD modeling and drug development.</p>","PeriodicalId":12321,"journal":{"name":"Fluids and Barriers of the CNS","volume":"21 1","pages":"79"},"PeriodicalIF":5.9,"publicationDate":"2024-10-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11468049/pdf/","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"142406211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":1,"RegionCategory":"医学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}