Infusion Of Cerebrospinal Fluid Research Articles

CSF formation rate—a potential glymphatic flow parameter in hydrocephalus?

BackgroundStudies indicate that brain clearance via the glymphatic system is impaired in idiopathic normal pressure hydrocephalus (INPH). This has been suggested to result from reduced cerebrospinal fluid (CSF) turnover, which could be caused by a reduced CSF formation rate. The aim of this study was to determine the formation rate of CSF in a cohort of patients investigated for INPH and compare this to a historical control cohort.MethodsCSF formation rate was estimated in 135 (75 ± 6 years old, 64/71 men/women) patients undergoing investigation for INPH. A semiautomatic CSF infusion investigation (via lumbar puncture) was performed. CSF formation rate was assessed by downregulating and steadily maintaining CSF pressure at a zero level. During the last 10 min, the required outflow to maintain zero pressure, i.e., CSF formation rate, was continuously measured. The values were compared to those of a historical reference cohort from a study by Ekstedt in 1978.ResultsMean CSF formation rate was 0.45 ± 0.15 ml/min (N = 135), equivalent to 27 ± 9 ml/hour. There was no difference in the mean (p = 0.362) or variance (p = 0.498) of CSF formation rate between the subjects that were diagnosed as INPH (N = 86) and those who were not (N = 43). The CSF formation rate in INPH was statistically higher than in the reference cohort (0.46 ± 0.15 vs. 0.40 ± 0.08 ml/min, p = 0.005), but the small difference was probably not physiologically relevant. There was no correlation between CSF formation rate and baseline CSF pressure (r = 0.136, p = 0.115, N = 135) or age (-0.02, p = 0.803, N = 135).ConclusionsThe average CSF formation rate in INPH was not decreased compared to the healthy reference cohort, which does not support reduced CSF turnover. This emphasizes the need to further investigate the source and routes of the flow in the glymphatic system and the cause of the suggested impaired glymphatic clearance in INPH.

Central nervous system multiple myeloma: A real-world multi-institutional study of the Greek Myeloma Study Group.

Central nervous system (CNS) involvement is a rare and aggressive complication of multiple myeloma (MM). We identified 54/4352 MM patients (1.2%), who developed CNS-MM between 2000 and 2022. A matched-control group of MM patients without CNS-MM was used for comparisons. Median age was 63 years. Median time to CNS-MM was 28 months; 6/54 experienced CNS-MM at MM diagnosis. Abnormal lactate dehydrogenase (LDH), high-risk cytogenetics, and extramedullary involvement (EMI), that is, soft tissue plasmacytomas and/or plasma cell leukemia (PCL), were more frequent in CNS-MM versus controls (p < .05); 13/54 had PCL at CNS-MM. The majority had leptomeningeal infiltration (LMI) (66%); 26% had CNS-MM without systemic myeloma; EMI was the strongest predictor for CNS-MM (OR: 6.3). Median overall survival (OS) of CNS-MM patients versus controls was 43 months (95% CI: 32-54) versus 60 months (95% CI: 38-82) (p < .001); treatment of CNS-MM included mainly bortezomib/thalidomide/chemotherapy whereas 20% received novel drugs/immunotherapy combinations; 28 patients underwent cerebrospinal fluid infusions; EMI was the strongest negative predictor for post CNS-MM OS (p = .005; HR: 2.9). Treatment after 2016 predicted significantly for OS (p = .002; HR: 0.27). Median post CNS-MM OS was 4 months (95% CI: 2.6-5.4); in patients treated after 2016 median OS was 12 months. In conclusion, we have demonstrated in this large real-world series that survival of CNS-MM remains poor; however, there is a positive impact of treatment after 2016, related to the efficacy of modern anti-myeloma therapy; EMI significantly increases the probability to develop CNS-MM and the risk of post CNS-MM death, indicating a potential need for CNS prophylaxis for those patients.

Inhibition of NF-κB with an Analog of Withaferin-A Restores TDP-43 Homeostasis and Proteome Profiles in a Model of Sporadic ALS.

The current knowledge on pathogenic mechanisms in amyotrophic lateral sclerosis (ALS) has widely been derived from studies with cell and animal models bearing ALS-linked genetic mutations. However, it remains unclear to what extent these disease models are of relevance to sporadic ALS. Few years ago, we reported that the cerebrospinal fluid (CSF) from sporadic ALS patients contains toxic factors for disease transmission in mice via chronic intracerebroventricular (i.c.v.) infusion. Thus a 14-day i.c.v. infusion of pooled CSF samples from ALS cases in mice provoked motor impairment as well as ALS-like pathological features. This offers a unique paradigm to test therapeutics in the context of sporadic ALS disease. Here, we tested a new Withaferin-A analog (IMS-088) inhibitor of NF-κB that was found recently to mitigate disease phenotypes in mouse models of familial disease expressing TDP-43 mutant. Our results show that oral intake of IMS-088 ameliorated motor performance of mice infused with ALS-CSF and it alleviated pathological changes including TDP-43 proteinopathy, neurofilament disorganization, and neuroinflammation. Moreover, CSF infusion experiments were carried out with transgenic mice having neuronal expression of tagged ribosomal protein (hNfL-RFP mice), which allowed immunoprecipitation of neuronal ribosomes for analysis by mass spectrometry of the translational peptide signatures. The results indicate that treatment with IMS-088 prevented many proteomic alterations associated with exposure to ALS-CSF involving pathways related to cytoskeletal changes, inflammation, metabolic dysfunction, mitochondria, UPS, and autophagy dysfunction. The effective disease-modifying effects of this drug in a mouse model based on i.c.v. infusion of ALS-CSF suggest that the NF-κB signaling pathway represents a compelling therapeutic target for sporadic ALS.

Update Analysis of Central Nervous System Multiple Myeloma Prognosis and Survival: A Real-World Multi-Institutional Study of the Greek Myeloma Study Group

Central Nervous System Multiple Myeloma (CNS-MM) is a rare but aggressive complication of MM, and its treatment remains an unmet clinical need. Herein we present a real-world national analysis of incidence, characteristics, prognostic factors and outcome of a large cohort of patients with CNS-MM. We evaluated 53 patients with CNS-MM (M/F: 23/30; median age: 59, range: 20-96 years; IgG: 27, IgA: 10, light-chain: 11, non-secretory: 4, IgD: 1; ISS1: 22, ISS2: 13, ISS3: 18; RISS1: 15, RISS2: 22, RISS3: 16) out of 4352 MM patients (1.2%), who were treated within the Greek Myeloma Study Group centers from 2000 to 2022 (23% of patients were diagnosed after 2016). A control group of MM patients matched for age, gender, and stage (ISS/RISS) who were treated during the same period was used for comparisons. Presence of soft tissue plasmacytomas (STP) and/or plasma cell leukemia (PCL; circulating plasma cells, cPCs: ≥5%) was determined and analyzed as extramedullary involvement (EMI). Median time to CNS-MM from MM diagnosis was 28 months (range 0-149 months); 6/53 (11.3%) patients experienced CNS-MM at initial MM diagnosis. Clinical manifestations of CNS-MM included visual disturbances/diplopia: 32%, paresis/paraplegia: 22%, lethargy/confusion: 37%, headache: 22%, cranial nerve palsy: 13% and dysarthria: 11%. PCL was present in 16/53 (30%) CNS-MM patients, while 29/53 (54.7%) CNS-MM patients had bone and/or STP vs. 13/53 matched controls (p=0.001); EMI was found in 24/53 (45%) patients with CNS-MM vs. 4/53 (7%) in controls (p&amp;lt;0.001). 35/53 (66%) CNS-MM patients had leptomeningeal infiltration (LMI) and 34% had intraparenchymal lesions. Median number of cells in the cerebrospinal fluid (CSF) was 60/μL (range 10-2550) and almost all of them (80%, range: 20-100%) were clonal plasma cells. Out of 53 CNS-MM patients, 14 (26.4%) had only CNS involvement without marrow infiltration by PCs; 51% had ≥1 high-risk molecular features (i.e., del17p, t4:14, t14:16, 1q+), and this was marginally higher vs. controls (36%; p=0.15). CD56 negative marrow PCs did not differ between groups (33% vs. 37%). A binary logistic regression analysis demonstrated that EMI was the strongest prognostic factor for the development of CNS-MM (p=0.01; HzR: 5.7). Median number of lines of treatment before the development of CNS-MM was 2 (range 0-9). First line anti-myeloma treatment in patients who developed CNS-MM included conventional chemotherapy (CT) or thalidomide-based regimens in 19 patients, bortezomib-based triplets in 27 and daratumumab-based regimens (DBR) in 7; this did not differ from controls. Overall response rate (ORR) in first-line therapy was similar between CNS-MM and controls (85% for both groups; CR 41% vs. 36%, respectively). After a median follow-up of 150 months post-MM diagnosis (95% CI: 107-192), 46 CNS-MM patients (87%) deceased (MM progression: 34, infection/sepsis: 10, cerebral hemorrhage: 2). Median overall survival (OS) of CNS-MM patients vs. matched controls from initial MM diagnosis was 43 months (95% CI: 31-54) vs 60 months (95% CI: 34-86) (p=0.002; Figure). Regarding CNS-MM therapy, 17 patients received IMiD-based regimens and 26 received PI-based regimens, 6 received CT and 4 received DBR. Patients with CNS-MM and marrow infiltration by PCs displayed an ORR of 31% only; CNS symptoms improved in 74% of all patients. Median OS of CNS-MM patients from the time of CNS involvement was 4 months (95% CI: 2.6-5.3), and it was longer in 12 patients treated after 2016 [18 months (95% CI: 7-29) vs. 2 months (95% CI: 1-3)]. Cerebrospinal fluid (CSF) infusions were performed in 28 patients (53%); 9 patients (19%) underwent radiotherapy. A multivariate analysis showed that EMI, either at diagnosis or during MM course, was the strongest negative predictor for post CNS-MM OS (p=0.008; HR: 3.4 95% CI: 1.4-8.0). Moreover, LMI was a negative predictor (p=0.02; HR: 2.7, 95% CI: 1.2-6.3) for OS, whereas treatment after 2016 had a positive impact (p=0.02; HR: 0.28, 95% CI: 0.12-0.8); CSF infusions did not affect OS. In conclusion, our analysis representing one of the largest real-world series of CNS MM patients after 2016, showed that, OS of CNS-MM remains poor however, there is a positive impact of treatment after 2016, reflecting the efficacy of modern anti-myeloma therapy; EMI strongly predicts for CNS-MM and induces a 3-fold increase in the probability of post CNS-MM death indicating a potential need for CNS prophylaxis in these patients.

Stereotactic and Functional Neurosurgery Convection-Enhanced Delivery of Autologous Cerebrospinal Fluid Enhances Basal Ganglia Visualization during MRI-Guided Deep Brain Stimulation Surgery

Introduction: The aim of this study was to determine the safety and feasibility of convection-enhanced delivery of autologous cerebrospinal fluid (CSF) for enhancing intraoperative magnetic resonance imaging (MRI) of the basal ganglia during stereotactic neurosurgery. Methods: This pilot study was conducted in 4 patients with Parkinson’s disease (PD) who underwent MRI-guided deep brain stimulation of the globus pallidus internus (GPi). CSF was obtained via lumbar puncture after general anesthesia and prior to incision. A frameless stereotaxy system was installed, and an infusion catheter was inserted to the GPi using intraoperative MRI. Infusion of autologous CSF was performed at a convective rate of 5 µL/min with a maximum volume of infusion (Vi) of 500 mL. T2-weighted MRI scans were obtained every 15 min up to a maximum of 105 min in order to calculate the volume of distribution (Vd). Safety was assessed with adverse event monitoring, and clinical outcomes were measured with changes in unmedicated UPDRS part III and PDQ-39 scores from baseline to 6 months postoperatively. Results: All four infusions were safe and without adverse events. The mean unmedicated UPDRS part III and PDQ-39 scores improved by 24% and 26%, respectively. The Vd:Vi ratio ranged from 2.2 to 2.8 and peaked 45 min from the onset of infusion, which is when the borders of the GPi could generally be visualized based on T2-weighted MRI. Two patients underwent refinement of the stereotactic targeting based on infusion-enhanced images. Conclusions: The convective administration of autologous CSF to deep brain structures appears safe and feasible for enhancing intraoperative MRI during stereotactic procedures. Infusion-enhanced imaging with target-specific infusates could be developed to visualize neurochemical circuits or cellular regions that currently are not seen with anatomic/structural MRI.

Cerebral hemodynamic monitoring combined with infusion test in hydrocephalus

IntroductionDisturbance in cerebrospinal fluid (CSF) circulation may overlap with abnormality of cerebral blood flow (CBF) in hydrocephalus. Transcranial Doppler (TCD) ultrasonography is a non-invasive technique able to assess CBF velocity (CBFv) dynamics in response to a controlled rise in ICP during CSF infusion tests. Research questionWhich TCD-derived cerebral hemodynamic parameters change during controlled rise of ICP, and in which direction? Material and methodsInfusion tests combined with TCD monitoring and non-invasive monitoring of arterial blood pressure (ABP) were conducted in 65 hydrocephalic patients. TCD-based hemodynamic variables: spectral pulsatility index (sPI), compliance of CSF space (Ci), cerebral autoregulation index (Mx), critical closing pressure (CrCP), cerebrovascular wall tension (WT) and diastolic closing margin (DCM-distance between diastolic ABP and CrCP) were calculated retrospectively. ResultsDuring the test ICP increased on average to 25 mm Hg (p < 0.0001), with a parallel decrease in cerebral perfusion pressure (CPP, p < 0.0003). The CBFv waveform changed, showing a rise in sPI (p < 0.0001). Ci decreased inversely proportional to a rise in ICP, and correlated well with changes of compliance calculated from the Marmarou model. CrCP increased in response to rising ICP (p < 0.001) while WT decreased (p < 0.002). DCM correlated with cerebrospinal elasticity (R = −0.31; p < 0.04). Cerebral autoregulation was worse in patients with normal CSF circulation, measured as resistance to CSF outflow (Rout): Pearson correlation between Mx and Rout was R = −0.41; p < 0.02. ConclusionA controlled rise in ICP affects cerebral hemodynamics in a moderate manner. Parameters like cerebral autoregulation index or DCM correlate with CSF dynamics and may be considered as supplementary variables for the diagnosis of hydrocephalus.

Infusion of Cerebrospinal Fluid from Young Mice Reverses Memory Loss in Aged Mice.

Infusion of Cerebrospinal Fluid from Young Mice Reverses Memory Loss in Aged Mice.

Addressing the Devil Within: Normal Pressure Hydrocephalus—A Narrative Review

AbstractNormal pressure hydrocephalus (NPH) is the most frequently occurring form of hydrocephalus among adults. It is characterized clinically by the classical triad, called Hakim's triad, comprising gait issues, cognitive impairment, and urinary problems. NPH may be primary or idiopathic (iNPH) or secondary. Characteristic neuroimaging features occur, which are vital to diagnosis. Diagnostic criteria in the form of Japanese guideline and Congress of Neurological Surgeons 2005 guidelines have been devised, and broadly, are based on a constellation of clinical and neuroimaging features, in association with cerebrospinal fluid (CSF) testing. CSF tap test, extended lumbar drainage, and CSF infusion tests are invasive diagnostic tests. CSF tap test and extended lumbar drainage are used to demonstrate clinical reversibility with CSF drainage, and patients who demonstrate this are candidates for CSF shunting. However, due to the low negative predictive value of these tests, potential response to shunting cannot be negated among patients who do not respond to CSF drainage. Various shunting procedures are used for treatment, including ventriculoperitoneal, lumboperitoneal, and ventriculoatrial shunts. Endoscopic third ventriculostomy has also been attempted with limited success. Among the clinical features, gait abnormalities are most responsive to shunting. Persistent long-term response to shunting has been reported. Patients need to be meticulously followed up after the shunting procedure, to assess clinical and neuroimaging response, and detect possible shunt-related complications, especially CSF over-drainage. Early treatment is associated with better prognosis, and it is crucial to recognize and treat this condition before the development of severe symptoms.

T2-Sampling Perfection With Application-Optimized Contrasts by Using Flip Angle Evolution (SPACE) Protocol MRI: A Safe, Minimally Invasive Screening Tool for Spinal CSF Leak Causing Spontaneous Intracranial Hypotension

Spontaneous intracranial hypotension (SIH) due to a spinal cerebrospinal fluid (CSF) leak is secondary cause of headache with potentially devastating consequences. Its diagnosis is complicated owing to the lack of a reasonable, minimally invasive screening test. This results in many patients remaining undiagnosed for years after the headache onset. Current testing approaches are either overly invasive, namely the CSF infusion protocol or both invasive and insensitive viz. lumbar puncture (LP) with an opening pressure (OP) or computed tomography myelogram (CTM). These diagnostic methods are frequently employed in a clinical setting since they require access to the thecal space; they unfortunately have a dearth of sensitivity. CTM will not document a leak if it is intermittent or very slow and in the setting of a spinal CSF leak, the OP on LP may be high, low, or normal. A potential remedy for this state is the T2-sampling perfection with application-optimized contrasts by using flip angle evolution (SPACE) protocol spinal magnetic resonance imaging (MRI). We present two cases that demonstrate its potential value as a screening tool. It is well known for its high sensitivity for identifying spinal pathology and is minimally invasive, making it a good choice for a screening modality when diagnosing possible SIH cases.

Motor behavioral abnormalities and histopathological findings in middle aged male Wistar rats inoculated with cerebrospinal fluid from patients with Amyotrophic Lateral Sclerosis

• Middle-aged male rats infused with CSF mimic pathogenic mechanisms observed in ALS. • Infusion of human CSF from patients of ALS causes motor impairment in middle-aged animals. • CSF from patients of ALS is a tool to investigate the characteristics of the disease. Amyotrophic Lateral Sclerosis (ALS) is a progressive neurodegenerative disease associated with loss of upper and lower motor neurons in the primary motor cortex and spinal cord, respectively. Motor deficits are the main clinical features observed in patients with the disease. However, it has been suggested that the presence of neurotoxic factors in the cerebrospinal fluid (CSF) from ALS patients causes loss of motor neurons. The present study investigated the motor and histopathological changes induced by intracerebroventricular (ICV) infusion of CSF from ALS patients in middle aged male Wistar rats. Middle aged male rats were divided into three groups: (1) control group, animals injected with artificial CSF solution; (2) N-ALS group, animals injected with CSF from volunteers without neurological disease; and (3) ALS group, animals inoculated with CFS from a patient with definite ALS. After surgical and infusion procedures, animals were evaluated in different motor tests (grip strength; catalepsy and open field tests). Moreover, animals’ spinal cords were histologically investigated. We observed that ALS-CSF infusion reduced grip strength and led to motor changes and reduction in the number of motor neurons and glial cells in thoracic and lumbar regions of spinal cord. However, CSF N-ALS caused reduction of nerve and glial cells in the thoracic but not in the lumbar region. Our data suggest that ALS-CSF is associated with neurodegenerative mechanisms observed in ALS pathology.

Comparative route of administration studies using therapeutic siRNAs show widespread gene modulation in Dorset sheep.

siRNAs comprise a class of drugs that can be programmed to silence any target gene. Chemical engineering efforts resulted in development of divalent siRNAs (di-siRNAs), which support robust and long-term efficacy in rodent and nonhuman primate brains upon direct cerebrospinal fluid (CSF) administration. Oligonucleotide distribution in the CNS is nonuniform, limiting clinical applications. The contribution of CSF infusion placement and dosing regimen on relative accumulation, specifically in the context of large animals, is not well characterized. To our knowledge, we report the first systemic, comparative study investigating the effects of 3 routes of administration — intrastriatal (i.s.), i.c.v., and intrathecal catheter to the cisterna magna (ITC) — and 2 dosing regimens — single and repetitive via an implanted reservoir device — on di-siRNA distribution and accumulation in the CNS of Dorset sheep. CSF injections (i.c.v. and ITC) resulted in similar distribution and accumulation across brain regions. Repeated dosing increased homogeneity, with greater relative deep brain accumulation. Conversely, i.s. administration supported region-specific delivery. These results suggest that dosing regimen, not CSF infusion placement, may equalize siRNA accumulation and efficacy throughout the brain. These findings inform the planning and execution of preclinical and clinical studies using siRNA therapeutics in the CNS.

Decreased pH in the aging brain and Alzheimer's disease

Using publicly available data sets, we compared pH in the human brain and the cerebrospinal fluid (CSF) of postmortem control and Alzheimer's disease cases. We further investigated the effects of long-term acidosis in vivo in the APP-PS1 mouse model of Alzheimer's disease. We finally examined in vitro whether low pH exposure could modulate the release of proinflammatory cytokines and the uptake of amyloid beta by microglia. In the human brain, pH decreased with aging. Similarly, we observed a reduction of pH in the brain of C57BL/6 mice with age. In addition, independent database analyses revealed that postmortem brain and CSF pH is further reduced in Alzheimer's disease cases compared with controls. Moreover, in vivo experiments showed that low pH CSF infusion increased amyloid beta plaque load in APP-PS1 mice. We further observed that mild acidosis reduced the amyloid beta 42–induced release of tumor necrosis factor–alpha by microglia and their capacity to uptake this peptide. Brain acidosis is associated with aging and might affect pathophysiological processes such as amyloid beta aggregation or inflammation in Alzheimer's disease.

Single Center Experience in Cerebrospinal Fluid Dynamics Testing.

Normal pressure hydrocephalus is more complex than a simple disturbance of the cerebrospinal fluid (CSF) circulation. Nevertheless, an assessment of CSF dynamics is key to making decisions about shunt insertion, shunt malfunction, and for further management if a patient fails to improve. We summarize our 25years of single center experience in CSF dynamics assessment using pressure measurement and analysis. 4473 computerized infusion tests have been performed. We have shown that CSF infusion studies are safe, with incidence of infection at less than 1%. Raised resistance to CSF outflow positively correlates (p<0.014) with improvement after shunting and is associated with disturbance of cerebral blood flow and its autoregulation (p<0.02). CSF infusion studies are valuable in assessing possible shunt malfunction in vivo and for avoiding unnecessary revisions. Infusion tests are safe and provide useful information for clinical decision-making for the management of patients suffering from hydrocephalus.

NMDAR Antibodies Alter Dopamine Receptors and Cause Psychotic Behavior in Mice.

The aim was to demonstrate that antibodies from patients with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis alter the levels of dopamine 1 receptor (D1R) and dopamine 2 receptor (D2R) and cause psychotic-like features in mice. Cultured rat hippocampal neurons were treated with cerebrospinal fluid (CSF) from patients with anti-NMDAR encephalitis or controls, and the effects on clusters of D1R and D2R were quantified. In vivo studies included 71 C57BL/6J mice that were chronically infused with CSF from patients or controls through ventricular catheters connected to subcutaneous osmotic pumps. Prepulse inhibition of the acoustic startling reflex (PPI; a marker of psychotic-like behavior), memory, locomotor activity, and the density of cell-surface and synaptic D1R, D2R, and NMDAR clusters were examined at different time points using reported techniques. In cultured neurons, CSF from patients, but not from controls, caused a significant decrease of cell-surface D1R and an increase of D2R clusters. In mice, CSF from patients caused a significant decrease of synaptic and total cell-surface D1R clusters and an increase of D2R clusters associated with a decrease of PPI. These effects were accompanied by memory impairment and a reduction of surface NMDARs, as reported in this model. The psychotic-like features, memory impairment, and changes in levels of D1R, D2R, and NMDAR progressively improved several days after the infusion of CSF from patients stopped. In addition to memory deficits and reduction of NMDARs, CSF antibodies from patients with anti-NMDAR encephalitis cause reversible psychotic-like features accompanied by changes (D1R decrease, D2R increase) in cell-surface dopamine receptor clusters. ANN NEUROL 2020 ANN NEUROL 2020;88:603-613.

Endogenous Na+, K+-ATPase inhibitors and CSF [Na+] contribute to migraine formation.

There is strong evidence that neuronal hyper-excitability underlies migraine, and may or may not be preceded by cortical spreading depression. However, the mechanisms for cortical spreading depression and/or migraine are not established. Previous studies reported that cerebrospinal fluid (CSF) [Na+] is higher during migraine, and that higher extracellular [Na+] leads to hyper-excitability. We raise the hypothesis that altered choroid plexus Na+, K+-ATPase activity can cause both migraine phenomena: inhibition raises CSF [K+] and initiates cortical spreading depression, while activation raises CSF [Na+] and causes migraine. In this study, we examined levels of specific Na+, K+-ATPase inhibitors, endogenous ouabain-like compounds (EOLC), in CSF from migraineurs and controls. CSF EOLC levels were significantly lower during ictal migraine (0.4 nM +/- 0.09) than from either controls (1.8 nM +/- 0.4) or interictal migraineurs (3.1 nM +/- 1.9). Blood plasma EOLC levels were higher in migraineurs than controls, but did not differ between ictal and interictal states. In a Sprague-Dawley rat model of nitroglycerin-triggered central sensitization, we changed the concentrations of EOLC and CSF sodium, and measured aversive mechanical threshold (von Frey hairs), trigeminal nucleus caudalis activation (cFos), and CSF [Na+] (ultra-high field 23Na MRI). Animals were sensitized by three independent treatments: intraperitoneal nitroglycerin, immunodepleting EOLC from cerebral ventricles, or cerebroventricular infusion of higher CSF [Na+]. Conversely, nitroglycerin-triggered sensitization was prevented by either vascular or cerebroventricular delivery of the specific Na+, K+-ATPase inhibitor, ouabain. These results affirm our hypothesis that higher CSF [Na+] is linked to human migraine and to a rodent migraine model, and demonstrate that EOLC regulates them both. Our data suggest that altered choroid plexus Na+, K+-ATPase activity is a common source of these changes, and may be the initiating mechanism in migraine.

A mouse model of seizures in anti-N-methyl-d-aspartate receptor encephalitis.

Seizures develop in 80% of patients with anti-N-methyl-d-aspartate receptor (NMDAR) encephalitis, and these represent a major cause of morbidity and mortality. Anti-NMDAR antibodies have been linked to memory loss in encephalitis; however, their role in seizures has not been established. We determined whether anti-NMDAR antibodies from autoimmune encephalitis patients are pathogenic for seizures. We performed continuous intracerebroventricular infusion of cerebrospinal fluid (CSF) or purified immunoglobulin (IgG) from the CSF of patients with anti-NMDAR encephalitis or polyclonal rabbit anti-NMDAR IgG, in male C57BL/6 mice. Seizure status during a 2-week treatment was assessed with video-electroencephalography. We assessed memory, anxiety-related behavior, and motor function at the end of treatment and assessed the extent of neuronal damage and gliosis in the CA1 region of hippocampus. We also performed whole-cell patch recordings from the CA1 pyramidal neurons in hippocampal slices of mice with seizures. Prolonged exposure to rabbit anti-NMDAR IgG, patient CSF, or human IgG purified from the CSF of patients with encephalitis induced seizures in 33 of 36 mice. The median number of seizures recorded in 2weeks was 13, 39, and 35 per mouse in these groups, respectively. We observed only 18 brief nonconvulsive seizures in 11 of 29 control mice (median seizure count of 0) infused with vehicle (n=4), normal CSF obtained from patients with noninflammatory central nervous system (CNS) conditions (n=12), polyclonal rabbit IgG (n=7), albumin (n=3), and normal human IgG (n=3). We did not observe memory deficits, anxiety-related behavior, or motor impairment measured at 2weeks in animals treated with CSF from affected patients or rabbit IgG. Furthermore, there was no evidence of hippocampal cell loss or astrocyte proliferation in the same mice. Our findings indicate that autoantibodies can induce seizures in anti-NMDAR encephalitis and offer a model for testing novel therapies for refractory autoimmune seizures.

New Insight into the Mechanism of Mannitol Effects on Cerebrospinal Fluid Pressure Decrease and Craniospinal Fluid Redistribution

Intracranial hypertension, which often follows a severe brain injury, is usually treated with intravenous (i.v.) application of hyperosmolar solutions. The mechanism of intracranial cerebrospinal fluid (CSF) pressure decrease after such a treatment is still unclear. The aim of this article was to try to explain the mechanism of CSF pressure reduction after i.v. hyperosmolar mannitol bolus in regard to the changes in CSF volume. Two types of experiments were done on anesthetized cats before and after hyperosmolar mannitol application: ventriculo-cisternal perfusion at different perfusion rates, simultaneously measuring the perfusate outflow volume, and CSF pressure recording in the lateral ventricle before and during artificial CSF infusion. Mannitol application in the first group of cats significantly reduced collected prefusate volume during ventriculo-cisternal perfusion, and in the second group it prevented CSF pressure increase caused by artificial CSF infusion. Our results strongly suggest that the mechanism of hyperosmolar mannitol action after its i.v. application is based on osmotic fluid retrieval from interstitial and cerebrospinal compartments into the microvessels. This shift, without significant volume change inside the cranium, causes a predominant decrease of CSF volume in the spinal part of the system, which in turn leads to lowering of the CSF pressure. Spinal CSF volume decrease is enabled by the extensibility of the spinal dura, this way providing the possibility for CSF volume redistribution inside the CSF system, together with CSF pressure decrease. This mechanism of mannitol action is in accordance with the new hypothesis of CSF physiology.

Histological changes in the rat brain and spinal cord following prolonged intracerebroventricular infusion of cerebrospinal fluid from amyotrophic lateral sclerosis patients are similar to those caused by the disease

IntroductionCerebrospinal fluid (CSF) from amyotrophic lateral sclerosis (ALS) patients induces cytotoxic effects in in vitro cultured motor neurons. Materials and methodsWe selected CSF with previously reported cytotoxic effects from 32 ALS patients. Twenty-eight adult male rats were intracerebroventricularly implanted with osmotic mini-pumps and divided into 3 groups: 9 rats injected with CSF from non-ALS patients, 15 rats injected with cytotoxic ALS-CSF, and 4 rats injected with a physiological saline solution. CSF was intracerebroventricularly and continuously infused for periods of 20 or 43days after implantation. We conducted clinical assessments and electromyographic examinations, and histological analyses were conducted in rats euthanised 20, 45, and 82days after surgery. ResultsImmunohistochemical studies revealed tissue damage with similar characteristics to those found in the sporadic forms of ALS, such as overexpression of cystatin C, transferrin, and TDP-43 protein in the cytoplasm. The earliest changes observed seemed to play a protective role due to the overexpression of peripherin, AKTpan, AKTphospho, and metallothioneins; this expression had diminished by the time we analysed rats euthanised on day 82, when an increase in apoptosis was observed. The first cellular changes identified were activated microglia followed by astrogliosis and overexpression of GFAP and S100B proteins. ConclusionOur data suggest that ALS could spread through CSF and that intracerebroventricular administration of cytotoxic ALS-CSF provokes changes similar to those found in sporadic forms of the disease.

Are Slow Waves of Intracranial Pressure Suppressed by General Anaesthesia?

Slow waves of intracranial pressure (ICP) are spontaneous oscillations with a frequency of 0.3-4 cycles/min. They are often associated with pathological conditions, following vasomotor activity in the cranial enclosure. This study quantifies the effects of general anaesthesia (GA) on the magnitude of B-waves compared with natural sleep and the conscious state. Four groups of 30 patients each were formed to assess the magnitude of slow waves. Group A and group B consisted of normal pressure hydrocephalus (NPH) patients, each undergoing cerebrospinal fluid (CSF) infusion studies, conscious and under GA respectively. Group C comprised conscious, naturally asleep hydrocephalic patients undergoing overnight ICP monitoring; group D, which included deeply sedated head injury patients monitored in the intensive care unit (ICU), was compared with group C. The average amplitude for group A patients was higher (0.23 ± 0.10 mmHg) than that of group B (0.15 ± 0.10 mmHg; p = 0.01). Overnight magnitude of slow waves was higher in group C (0.20 ± 0.13 mmHg) than in group D (0.11 ± 0.09 mmHg; p = 0.002). Slow waves of ICP are suppressed by GA and deep sedation. When using slow waves in clinical decision-making, it is important to consider the patients' level of consciousness to avoid incorrect therapeutic and management decisions.

Effects of sustained i.c.v. infusion of lupus CSF and autoantibodies on behavioral phenotype and neuronal calcium signaling

Systemic lupus erythematosus (SLE) is a potentially fatal autoimmune disease that is often accompanied by brain atrophy and diverse neuropsychiatric manifestations of unknown origin. More recently, it was observed that cerebrospinal fluid (CSF) from patients and lupus-prone mice can be neurotoxic and that acute administration of specific brain-reactive autoantibodies (BRAs) can induce deficits in isolated behavioral tasks. Given the chronic and complex nature of CNS SLE, the current study examines broad behavioral performance and neuronal Ca2+ signaling in mice receiving a sustained infusion of cerebrospinal fluid (CSF) from CNS SLE patients and putative BRAs (anti-NR2A, anti-ribosomal P, and anti-α-tubulin). A 2-week intracerebroventricular (i.c.v.) infusion of CSF altered home-cage behavior and induced olfactory dysfunction, excessive immobility in the forced swim test, and perseveration in a learning task. Conversely, sustained administration of purified BRAs produced relatively mild, both inhibitory and stimulatory effects on olfaction, spatial learning/memory, and home-cage behavior. In vitro studies revealed that administration of some CSF samples induces a rapid influx of extracellular Ca2+ into murine neurons, an effect that could be partially mimicked with the commercial anti-NR2A antibody and blocked with selective N-methyl-D-aspartate (NMDA) receptor antagonists. The current findings confirm that the CSF from CNS SLE patients can be neuroactive and support the hypothesis that intrathecal BRAs induce synergistically diverse effects on all domains of behavior. In addition, anti-NMDA receptor antibodies may alter Ca2+ homeostasis of central neurons, thus accounting for excitotoxicity and contributing to the heterogeneity of psychiatric manifestations in CNS SLE and other autoantibody-related brain disorders.