Intraventricular dimethyl sulfoxide (DMSO) induces hydrocephalus in a dose-dependent pattern

Introduction

Dimethyl sulfoxide (DMSO), a widely utilized solvent in the medical industry, has been associated with various adverse effects, even at low concentrations, including damage to mitochondrial integrity, altered membrane potentials, caspase activation, and apoptosis. Notably, therapeutic molecules for central nervous system treatments, such as embolic agents or some chemotherapy drugs that are dissolved in DMSO, have been associated with hydrocephalus as a secondary complication. Our study investigated the potential adverse effects of DMSO on the brain, specifically focusing on the development of hydrocephalus and the effect on astrocytes.

Methods

Varied concentrations of DMSO were intraventricularly injected into 3-day-old mice, and astrocyte cultures were exposed to similar concentrations of DMSO. After 14 days of injection, magnetic resonance imaging (MRI) was employed to quantify the brain ventricular volumes in mice. Immunofluorescence analysis was conducted to delineate DMSO-dependent effects in the brain. Additionally, astrocyte cultures were utilized to assess astrocyte viability and the effects of cellular apoptosis.

Results

Our findings revealed a dose-dependent induction of ventriculomegaly in mice with 2%, 10%, and 100% DMSO injections (p < 0.001). The ciliated cells of the ventricles were also proportionally affected by DMSO concentration (p < 0.0001). Furthermore, cultured astrocytes exhibited increased apoptosis after DMSO exposure (p < 0.001).

Conclusion

Our study establishes that intraventricular administration of DMSO induces hydrocephalus in a dose-dependent manner. This observation sheds light on a potential explanation for the occurrence of hydrocephalus as a secondary complication in intracranial treatments utilizing DMSO as a solvent.

Polyvinylpyrrolidone-coated catheters decrease choroid plexus adhesion and improve flow/pressure performance in an in vitro model of hydrocephalus

PURPOSE

Proximal catheter obstruction is the leading cause of ventricular shunt failure in pediatric patients. Our aim is to evaluate various types of shunt catheters to assess in vitro cellular adhesion and obstruction.

METHODS

Four catheter types were tested: (1) antibiotic and impregnated, (2) barium-stripe polyvinylpyrrolidone coated (PVP), (3) barium-stripe, and (4) barium-impregnated. Catheters were seeded with choroid plexus epithelial cells to test cellular adhesion and inoculated with the same cells to test flow/pressure performance under choroid plexus growth conditions. Ventricular catheters were placed into a three-dimensional printed phantom ventricular replicating system through which artificial cerebrospinal fluid (CSF) was pumped. Differential pressure sensors were used to measure catheter performance.

RESULTS

PVP catheters had the lowest median cell attachment (10 cells) compared to antibiotic-impregnated (230 cells), barium stripe (513 cells), and barium-impregnated (146 cells) catheters after culture (p < 0.01). In addition, PVP catheters (- 0.247 cm H2O) and antibiotic-impregnated (- 1.15 cm H2O) catheters had significantly lower pressure in the phantom ventricular system compared to the barium stripe (0.167 cm H2O) and barium-impregnated (0.618 cm H2O; p < 0.01) catheters.

CONCLUSIONS

PVP catheters showed less cellular adhesion and, together with antibiotic-impregnated catheters, required less differential pressure to maintain a consistent flow. Our findings suggest clinical relevance for using PVP ventricular catheters in patients with recurrent catheter obstruction by choroid plexus.

Polyvinylpyrrolidone-Coated Catheters Decrease Astrocyte Adhesion and Improve Flow/Pressure Performance in an Invitro Model of Hydrocephalus

The leading cause of ventricular shunt failure in pediatric patients is proximal catheter occlusion. Here, we evaluate various types of shunt catheters to assess in vitro cellular adhesion and obstruction. The following four types of catheters were tested: (1) antibiotic- and barium-impregnated, (2) polyvinylpyrrolidone, (3) barium stripe, and (4) barium impregnated. Catheters were either seeded superficially with astrocyte cells to test cellular adhesion or inoculated with cultured astrocytes into the catheters to test catheter performance under obstruction conditions. Ventricular catheters were placed into a three-dimensional printed phantom ventricular replicating system through which artificial CSF was pumped. Differential pressure sensors were used to measure catheter performance. Polyvinylpyrrolidone catheters had the lowest median cell attachment compared to antibiotic-impregnated (18 cells), barium stripe (17 cells), and barium-impregnated (21.5 cells) catheters after culture (p < 0.01). In addition, polyvinylpyrrolidone catheters had significantly higher flow in the phantom ventricular system (0.12 mL/min) compared to the antibiotic coated (0.10 mL/min), barium stripe (0.02 mL/min) and barium-impregnated (0.08 mL/min; p < 0.01) catheters. Polyvinylpyrrolidone catheters showed less cellular adhesion and were least likely to be occluded by astrocyte cells. Our findings can help suggest patient-appropriate proximal ventricular catheters for clinical use.

Partial Obstruction of Ventricular Catheters Affects Performance in a New Catheter Obstruction Model of Hydrocephalus

OBJECTIVE

One of the major causes of cerebral ventricular shunt failure is proximal catheter occlusion. We describe a novel ventricular cerebrospinal fluid (CSF) flow replicating system that assesses pressure and flow responses to varying degrees of catheter occlusion.

METHODS

Ventricular catheter performance was assessed during conditions of partial and complete occlusion. The catheters were placed into a three-dimensionally-printed phantom ventricular replicating system. Artificial CSF was pumped through the ventricular system at a constant rate of 1 mL/min to mimic CSF flow, with the proximal end of the catheter in the phantom ventricle. Pressure transducer and flow rate sensors were used to measure intra-phantom pressure, outflow pressure, and CSF flow rates. The catheters were also inserted into silicone tubing and pressure was measured in the same manner for comparison with the phantom.

RESULTS

Pressure measured in the ventricle phantom did not change when the outflow of the ventricular catheter was partially occluded. However, the intraventricular phantom pressure significantly increased when the outflow catheter was 100% occluded. The flow through the catheter showed no significant difference in rate with any degree of partial occlusion of the catheter. At the distal end of the partially occluded catheters, there was less pressure compared with the nonoccluded catheters. This difference in pressure in partially occluded catheters correlated with the percentage of catheter hole occlusion.

CONCLUSIONS

Our model mimics the physiological dynamics of the CSF flow in partially and completely obstructed ventricular catheters. We found that partial occlusion of the catheter had no effect on the CSF flow rate, but did reduce outflow pressure from the catheter.

AQP4 labels a subpopulation of white matter-dependent glial radial cells affected by pediatric hydrocephalus, and its expression increased in glial microvesicles released to the cerebrospinal fluid in obstructive hydrocephalus

Hydrocephalus is a distension of the ventricular system associated with ventricular zone disruption, reactive astrogliosis, periventricular white matter ischemia, axonal impairment, and corpus callosum alterations. The condition's etiology is typically attributed to a malfunction in classical cerebrospinal fluid (CSF) bulk flow; however, this approach does not consider the unique physiology of CSF in fetal and perinatal patients. The parenchymal fluid contributes to the glymphatic system, and plays a fundamental role in pediatric hydrocephalus, with aquaporin 4 (AQP4) as the primary facilitator of these fluid movements. Despite the importance of AQP4 in the pathophysiology of hydrocephalus, it’s expression in human fetal life is not well-studied. This manuscript systematically defines the brain expression of AQP4 in human brain development under control (n = 13) and hydrocephalic conditions (n = 3). Brains from 8 postconceptional weeks (PCW) onward and perinatal CSF from control (n = 2), obstructive (n = 6) and communicating (n = 6) hydrocephalic samples were analyzed through immunohistochemistry, immunofluorescence, western blot, and flow cytometry. Our results indicate that AQP4 expression is observed first in the archicortex, followed by the ganglionic eminences and then the neocortex. In the neocortex, it is initially at the perisylvian regions, and lastly at the occipital and prefrontal zones. Characteristic astrocyte end-feet labeling surrounding the vascular system was not established until 25 PCW. We also found AQP4 expression in a subpopulation of glial radial cells with processes that do not progress radially but, rather, curve following white matter tracts (corpus callosum and fornix), which were considered as glial stem cells (GSC). Under hydrocephalic conditions, GSC adjacent to characteristic ventricular zone disruption showed signs of early differentiation into astrocytes which may affect normal gliogenesis and contribute to the white matter dysgenesis. Finally, we found that AQP4 is expressed in the microvesicle fraction (p < 0.01) of CSF from patients with obstructive hydrocephalus. These findings suggest the potential use of AQP4 as a diagnostic and prognostic marker of pediatric hydrocephalus and as gliogenesis biomarker.

EPEN-12. MULTIPLE RECURRENCES OF ANAPLASTIC EPENDYMOMA WITH EXTRA AXIAL AND EXTRA NEURAL METASTASIS IN A PEDIATRIC PATIENT

Background

Ependymomas are the third most common CNS tumor in the pediatric population, accounting for 10% of all CNS tumors. Co-occurring extraneural and extracranial metastasis of ependymomas are extremely rare, with only 1 reported adult case in current literature.

Case Description

We describe the case of a patient with multiple reoccurrences of anaplastic ependymoma. Initial imaging showed a 5 x 8 x 8 cm complex cystic mass with nodular enhancing components within the left occipital lobe. The 4^th ventricle was intact and imaging was negative for metastasis. Pathology following resection demonstrated perivascular pseudorosettes, areas of calcification, and increased mitotic activity. Biopsy revealed GFAP, EMA, neurofilament, INI-1, and was negative for CAM5.2, confirming anaplastic ependymoma. Methylation studies for PFA or PFB subgroup differentiation were not available. The patient had recurrences at 4-, 5-, and 6-years after his initial diagnosis. Seven years from his initial diagnosis, the patient underwent resection of four nodular lesions from the occipital lobe and surrounding soft tissue. Pathology of these lesions and the lymph nodes/soft tissue confirmed anaplastic ependymoma. A PET scan showed increase uptake in the supraclavicular lymph nodes and had multiple bilateral pulmonary nodules. Scans at 3 months post-surgery were negative for leptomeningeal metastases but showed further lymph node involvement with progression of pulmonary disease.

Conclusion

Co-occurring extraneural and extracranial metastasis of ependymoma is a rare occurrence across all populations. To our knowledge, this would be the first published pediatric case of anaplastic ependymoma with lymph node, soft tissue, and pulmonary involvement. Treatment of ependymoma itypically local and the utility of chemotherapy remains unclear. Treatment options for extraneural mets is very limited, illustrating the need for new therapies and further studies directed at understanding the biology of these tumors and the factors that could influence their ability to metastasize to extraneural and extracranial sites.

MBCL-38. UNUSUAL EXTRANEURAL METASTASIS OF PEDIATRIC EMBRYONAL TUMORS: TWO CASE REPORTS

We report two cases of unusual extraneural metastasis in patients with embryonal tumors without central nervous system disease progression and prolonged survival. The first patient presented at 16 years of age with atypical teratoid rhabdoid tumor of the cervical spine. The tumor was confirmed to have loss of INI1, SMARCB1 deletion of exons 1–3, and heterozygous deletion of 22q11.2. The patient received treatment initially per ACNS0333 with high dose chemotherapy and tandem autologous transplants. The patient developed a biopsy-confirmed liver metastasis six months from diagnosis and, subsequently, had disease progression including liver metastases, bony lesions, muscle involvement, and lung nodules. Two and a half years from diagnosis the patient has still not had a relapse in the CNS. The second patient presented with medulloblastoma isolated to the posterior fossa at 11 years of age and was treated on SJMB03 protocol with craniospinal irradiation and high dose chemotherapy. He had his first recurrence in the temporal lobe three years post treatment. He had multiple recurrences in the brain over the next five years treated with re-resections, adjuvant chemotherapy, and gamma knife radiotherapy. He then developed cervical lymphadenopathy, bony lesions, liver lesions, and lung nodules. Cervical lymph node biopsy confirmed medulloblastoma. Next generation sequencing from recurrent tumor showed somatic mutations in p53, KDM6A, and PPP2R1A. Fourteen years from treatment, he has now developed a temporal lobe lesion. These cases are notable for prolonged survival despite widely metastatic disease and genomics predicting poor prognosis as well as metastatic disease disproportionate to CNS disease.

FloSeal hemostatic matrix use for intraventricular hemorrhage during a neuroendoscopic procedure

INTRODUCTION

Neuroendoscopy is a rapidly growing field, but the risk of intraventricular hemorrhage is signficant. There are few novel ways of obtaining hemostasis for major hemorrhage described in the literature.

PATIENT

A 5-year-old boy with a history of intraventricular hemorrhage and multi-cystic hydrocephalus presented with worsening brainstem compression from dilation of a 4 (th) ventricle cyst.

RESULTS

During endoscopic surgery to fenestrate the cyst, arterial hemorrhage was emergently controlled with the hemostatic agent, FloSeal.

CONCLUSION

To the best of the authors' knowledge, this is the first report of a patient with intraoperative intraventricular hemorrhage controlled with FloSeal.

Performance and complications associated with the synchromed 10-ml infusion pump for intrathecal baclofen administration in children

OBJECT

The objectives of this multicenter study were to monitor the performance of a 10-ml pump infusing intrathecal baclofen to treat 100 children with cerebral spasticity, to monitor complications associated with the pump, and to correlate pump-related complications with body habitus.

METHODS

Age at implantation of the pump ranged from 1.4 to 16.8 years (mean 8.1 years). The effects of ITB on spasticity in the upper and lower extremities were evaluated using the Ashworth Scale. Data were collected regarding implant site, infection, complication, and body mass index (BMI). Ashworth Scale scores decreased significantly in the upper and lower extremities at 6 and 12 months after pump implantation (p < 0.001). There were four serious system-related complications, all specific to catheters. There were 32 serious procedure-related complications in 21 patients: 11 complications were infections that occurred in nine patients. Four of nine pump-induced infections were treated with pump removal and antibiotic therapy; five infections were treated successfully with antibiotic therapy alone, without pump removal. In children younger than 8 years of age there was a significantly higher incidence of serious procedure-related adverse events than in older children. There was no significant correlation between BMI and the incidence of pump pocket-related complications or infections.

CONCLUSIONS

The 10-ml pump can be used therapeutically in small children, particularly those weighing less than 40 lbs, with greater ease and less wound tension, than the conventional 18-ml pump. The incidence of complications associated with the 10-ml pump in younger children appears to be similar to that previously reported with the 18-ml pump in larger-sized children.