High-Speed Video Microscopy of Ependymal Cilia in Brain Organotypic and Cell Culture Models

The wall of the ventricular system within the neuraxis is lined almost entirely by E1 ependymal cells, each of which projects multiple motile cilia from their apical surface into the cerebrospinal fluid (CSF). This specialized layer of E1 cells constitutes the border between the CSF and the brain interstitial fluid (BIF), and by controlling influx and efflux across the CSF to BIF interface, it is increasingly recognized to play an integral role in modulating and maintaining the brain microenvironment. The motile cilia have been shown to be responsive to changes in the CSF microenvironment, and while the physiological role of this mechanism remains incompletely understood, manipulating this control mechanism may influence the brain microenvironment potentially opening a new frontier in therapeutic intervention.In this paper, we describe our techniques for preparing organotypic slices from the murine brain parenchyma and establishing cell cultures of multiciliated ependymal cells from mouse and rat neonatal brain tissue. Our methodology generates a functional readout of ciliary function, specifically high-speed video microscopy (HSVM) enables the quantification of ciliary beat frequency (CBF), and characterization of ciliary beat pattern.

FP2-6 Modelling neonatal intraventricular haemorrhage using organotypic samples from the wall of the lateral ventricle

Objectives

Intraventricular Haemorrhage (IVH) impacts on ependyma and neural stem cells (NSC) within the subventricular zone.1 Developing therapeutic interventions to curtail this impact is a key research goal. Organotypic models from the wall of the lateral ventricle (LV) of mice2 and humans have the potential to offer unique insight into the dynamic impact of IVH.

Design

Basic science research using whole mount preparations (WMP) from the wall of the LV from mice and humans (SOLVe trial: IRAS ID 247936).

Subjects

Transgenic mouse line: Fucci:hGFAPCreER:TomatoTD. Human samples from children undergoing surgery for medically intractable epilepsy.

Methods

Using a published protocol2 WMP of the LV were prepared. Two samples of human CSF were acquired: a ‘haemorrhagic’ sample from a neonate with IVH and a ‘clean’ sample from a newborn undergoing repair of myelomeningocele. 72 hours time-lapse confocal microscopy was undertaken from multiple wells.

Results

Colocalisation of GFP (Fucci+ve) in hGFAP +ve (RFP +ve) cells revealed dividing NSC within the wall of the LV. Quantification of fucci +ve cells revealed ‘haemorrhagic’ CSF caused a significant reduction in proliferation whilst ‘clean’ CSF caused a significant increase in early proliferation.

Conclusions

Organotypic slice preparation from mice and human lateral ventricle represents a novel approach to investigating the impact of IVH on the wall of the lateral ventricle.

References

Back SA, Miller SP. Brain injury in premature neonates: A primary cerebral dysmaturation disorder? Ann Neurol 2014 April;75(4):469–86.

Obernier K, Cebrian-Silla A, Thomson M, Parraguez JI, Anderson R, Guinto C, Rodas Rodriguez J, Garcia-Verdugo JM, Alvarez-Buylla A. Adult neurogenesis is sustained by symmetric self-renewal and differentiation. Cell Stem Cell2018February 1;22(2):221–234.

P94 Ventricular subgaleal shunting is a safe and effective temporising measure for the treatment of neonatal post haemorrhagic hydrocephalus

Objectives

The use of a temporising device to facilitate neonatal maturation prior to permanent ventricular peritoneal shunt (VPS) remains gold standard treatment for neonatal posthaemorrhagic hydrocephalus (PHH). The relative superiority of ventricular access device (VAD) or ventricular subgaleal shunt (VSG) remains contentious.

Design

Retrospective case note review.

Subjects

49 neonates born between Sept 2012 to April 2018: (M:F 34:15); Average: gestation 26+3 (23 to 32+5); birth weight 870 g (±355 g); Papile grade 3:4 (ratio ≈ 1:2).

Methods

Computer records from neonatal VSG at a single tertiary care children’s hospital reviewed.

Results

Early complications associated with VSG seen in 13 cases (27%). Migration of shunt n=3, infection n=2, inadequate control of ventricular volume n=5, decompression haemorrhage n=2, wound leak n=1. All patients managed on NICU with an average inpatient stay of 5 days (range 2 to 15). 5 outcome groups defined: 1. Patient died (non neurological cause) (n=4) 2. VSG in situ for <1 year (n=7) 3. VSG and no VPS (n=6 16%) 4. VSG and VPS X1 never revised (n=17 45%) 5. VSG and VPS with revisions (n=15 39%) Rate of shunting in patients with VSG >1 year=84%. All patients that needed permanent VPS were operated within the first year. The average time elapsed prior to VPS was 86 days with over 80% of cases shunted within 100 days.

Conclusions

VSG remains a safe method of temporary CSF drainage for the treatment of neonatal PHH with rates of shunting in line with the published literature.

Neuroendoscopic surgery in children: does age at intervention influence safety and efficacy? A single-center experience

OBJECTIVE The aim of this study was to review the safety of pediatric intraventricular endoscopy across separate age groups and to determine whether intraventricular endoscopy is associated with an increased risk of complications or reduced efficacy in infants younger than 1 year. METHODS In this retrospective cohort study, 286 pediatric patients younger than 17 years underwent intraventricular endoscopy at Great Ormond Street Hospital between December 2005 and December 2014. The primary diagnosis, procedure, and complications were recorded. RESULTS Neuroendoscopic surgery was performed in 286 pediatric patients (51 neonates 0-6 months [Group 1]; 37 infants 6-12 months [Group 2]; 75 patients 1-5 years [Group 3]; 54 patients 5-10 years [Group 4]; and 69 patients ≥ 10 years [Group 5]; male/female ratio 173:113). The most common procedures included endoscopic third ventriculostomy (ETV) in 159 patients and endoscopic fenestration of intracranial cysts in 64 patients. A total of 348 consecutive neuroendoscopic procedures were undertaken. Nine different complications were identified, of which postoperative seizures (1.7%), CSF leak (3.1%), CSF infection (2.4%), and intracranial hemorrhage (1.7%) were the most common. Specifically, no significant difference in complication rate (11.9%) or infection rate (2.4%) was observed among age groups (p = 0.40 and p = 0.91, respectively). In addition, there were no perioperative deaths; 30-day mortality was 1.1%. After neuroendoscopy for CSF diversion (n = 227), a significantly higher rate of shunt insertion was observed in the youngest group (Group 1, 63.0%) when compared with older groups (Group 2, 46.4%; Group 3, 26.3%; Group 4, 38.6%; and Group 5, 30.8%; p = 0.03). Similarly, for patients who underwent ETV as their initial neuroendoscopic procedure or in combination with additional surgical interventions (n = 171), a significantly higher rate of shunt insertion was also observed within young infants (Group 1, 67.9%; Group 2, 47.6%; Group 3, 19.6%; Group 4, 27.3%; and Group 5, 23.3%; p = 0.003). CONCLUSIONS Intraventricular endoscopy is a safe neurosurgical intervention in pediatric patients of all ages, although it might be associated with increased shunt rates after endoscopic surgery, specifically ETV, in younger infants.

Moderate-Grade Germinal Matrix Haemorrhage Activates Cell Division in the Neonatal Mouse Subventricular Zone

Precise temporal and spatial control of the neural stem/progenitor cells within the subventricular zone (SVZ) germinal matrix of the brain is important for normal development in the third trimester and the early postnatal period. The high metabolic demands of proliferating germinal matrix precursors, coupled with the flimsy structure of the germinal matrix cerebral vasculature, are thought to account for the high rates of haemorrhage in extremely- and very-low-birth-weight preterm infants. Germinal matrix haemorrhage can commonly extend to intraventricular haemorrhage (IVH). Because neural stem/progenitor cells are sensitive to microenvironmental cues from the ventricular, intermediate, and basal domains within the germinal matrix, haemorrhage has been postulated to impact neurological outcomes through aberration of normal neural stem/progenitor cell behaviour. We developed an animal model of neonatal germinal matrix haemorrhage using stereotactic injection of autologous blood into the mouse neonatal germinal matrix. Pathological analysis at 4 days postinjury showed high rates of intraventricular extension and ventricular dilatation but low rates of parenchymal disruption outside the germinal zone, recapitulating key features of human “Papile grade III” IVH. At 4 days postinjury we observed proliferation in the wall of the lateral ventricle with significantly increased numbers of transient amplifying cells within the SVZ and the corpus callosum. Analysis at 21 days postinjury revealed that cortical development was also affected, with increased neuronal and concomitant reduced oligodendroglial differentiation. At the molecular level, we showed downregulation of the expression of the transmembrane receptor Notch2 in CD133+ve cells of the SVZ, raising the possibility that the burst of precocious proliferation seen in our experimental mouse model and the skewed differentiation could be mediated by downregulation of the Notch pathway within the proximal/ventricular domain. These findings raise the possibility that Notch regulation plays a critical role in mediating the response of the neonatal SVZ to ischaemic and haemorrhagic insults.

Microfracture of a baclofen pump catheter with intermittent under- and overdose

An 8-year-old boy with an implanted intrathecal baclofen pump presented with intermittent signs of baclofen under- and overdose. Pump interrogation, pump volumes, plain X-rays, catheter contrast fluoroscopy and CT of the intrathecal catheter tip were unremarkable. A microfracture of the extradural catheter was only seen at a magnification of x20 and confirmed by scanning electron microscopy. Symptoms resolved following replacement. Microfracture of the intrathecal catheter of baclofen pump systems may present puzzling symptomatology and be difficult to diagnose by conventional means.