Subventricular zone stem cell niche injury is associated with intestinal perforation in preterm infants and predicts future motor impairment

Brain injury is highly associated with preterm birth. Complications of prematurity, including spontaneous or necrotizing enterocolitis (NEC)-associated intestinal perforations, are linked to lifelong neurologic impairment, yet the mechanisms are poorly understood. Early diagnosis of preterm brain injuries remains a significant challenge. Here, we identified subventricular zone echogenicity (SVE) on cranial ultrasound in preterm infants following intestinal perforations. The development of SVE was significantly associated with motor impairment at 2 years. SVE was replicated in a neonatal mouse model of intestinal perforation. Examination of the murine echogenic subventricular zone (SVZ) revealed NLRP3-inflammasome assembly in multiciliated FoxJ1+ ependymal cells and a loss of the ependymal border in this postnatal stem cell niche. These data suggest a mechanism of preterm brain injury localized to the SVZ that has not been adequately considered. Ultrasound detection of SVE may serve as an early biomarker for neurodevelopmental impairment after inflammatory disease in preterm infants.

An easy and cost-effective method for the isolation and culturing of neural stem/progenitor cells from the subventricular (SVZ) and dentate gyrus (DG) of adult mouse brain

BACKGROUND

Isolation of adult Neural Stem/Progenitor Cells (NSPCs) from their neurogenic niches, is a prerequisite for studies involving culturing of NSPCs as neurospheres or attached monolayers in vitro. The currently available protocols involve the use of multiple animals and expensive reagents to establish the NSPCs culture.

NEW METHOD

This unit describes a method to isolate and culture NSPCs from the two neurogenic niches in the mouse brain, the Subventricular Zone (SVZ) and Dentate gyrus (DG)/subgranular zone (SGZ), in an easy and cost-effective manner.

RESULTS

NSPCs from SVZ and DG regions of adult mouse brains were isolated and cultured up to passage 15 without losing their stem/progenitor characteristics. These NSPCs could be differentiated into neurons, astrocytes, and oligodendrocytes, revealing its trilineage potential.

COMPARISON WITH EXISTING METHODS

This protocol eliminates the need for multiple animals as well as the use of many expensive reagents mentioned in previous protocols, adding to the cost-effectiveness of experiments. In addition, we have effectively reduced the number of steps involved in isolation and propagation, thereby minimizing the chances of contamination.

CONCLUSION

Our simplified protocol for the isolation and culturing of adult NSPCs from the SVZ and DG demonstrates a cost-effective and efficient alternative to existing methods, reducing the need for sacrificing many animals and the usage of expensive reagents. This method permits the long-term maintenance of NSPCs' stem/progenitor characteristics and their effective differentiation into the major types of cells in the brain, making it a valuable resource for researchers in the field.

BASIC PROTOCOL

Isolation and Culturing of Neural Stem/Progenitor cells from the Sub ventricular Zone and the Dentate Gyrus of the adult mouse brain. SUPPORT PROTOCOL 1: Cryopreservation, and revival of frozen NSPCs. SUPPORT PROTOCOL 2: Preparation of adherent monolayer cultures of neural stem/progenitor cells for the differentiation into multiple lineages SUPPORT PROTOCOL 3: Differentiation of NSPCs to neuronal and glial lineages SUPPORT PROTOCOL 4: Characterization of differentiated cells by immunocytochemistry.

Septostomy and Monroplasty in Isolated Lateral Ventricle After Removal of a Third Ventricle Colloid Cyst: 2-Dimensional Operative Video

Isolated unilateral hydrocephalus (IUH) is a condition caused by unilateral obstruction of the foramen of Monro.1 Etiopathogenic causes include tumors, congenital lesions, infective ventriculitis, intraventricular haemorrhage, and iatrogenic causes such as the presence of contralateral shunts.2,3 Neuroendoscopic management is considered the "gold-standard" treatment in IUH.4 Even if endoscopic septostomy and foraminoplasty in IUH are well-known procedures,5,6 IUH after an interhemispheric transcallosal transchoroidal approach for removal of a III ventricle colloid cyst is a complication barely described in literature. Video 1 describes this rare complication and the neuroendoscopic treatment adopted, including the operative room setup, patient's positioning, instrumentation needed, and a series of intraoperative tips for the performance of septostomy and Monroplasty via a single, precoronal burr hole. The scalp entry point and endoscope trajectory, homolateral to the dilated ventricle, were planned on the neuronavigation system. The avascular septal zone away from the septal veins and body of the fornix was reached, and the ostomy was performed. At the end of the procedure, Monroplasty was performed, too. The procedure was effective in solving the hydrocephalus and patient's clinical picture. No surgical complications occurred. Imaging demonstrated an evident and progressive reduction of enlarged lateral ventricle. In authors' opinion, the single burr-hole approach, ipsilateral to the enlarged ventricle, provides an optimal identification the intraventricular anatomy and allows Monroplasty to be performed, if deemed feasible during surgery. The patient consented to the procedure. The participants and any identifiable individuals consented to publication of their images.

Towards validation in clinical routine: a comparative analysis of visual MTA ratings versus the automated ratio between inferior lateral ventricle and hippocampal volumes in Alzheimer's disease diagnosis

PURPOSE

To assess the performance of the inferior lateral ventricle (ILV) to hippocampal (Hip) volume ratio on brain MRI, for Alzheimer's disease (AD) diagnostics, comparing it to individual automated ILV and hippocampal volumes, and visual medial temporal lobe atrophy (MTA) consensus ratings.

METHODS

One-hundred-twelve subjects (mean age ± SD, 66.85 ± 13.64 years) with varying degrees of cognitive decline underwent MRI using a Philips Ingenia 3T. The MTA scale by Scheltens, rated on coronal 3D T1-weighted images, was determined by three experienced radiologists, blinded to diagnosis and sex. Automated volumetry was computed by icobrain dm (v. 5.10) for total, left, right hippocampal, and ILV volumes. The ILV/Hip ratio, defined as the percentage ratio between ILV and hippocampal volumes, was calculated and compared against a normative reference population (n = 1903). Inter-rater agreement, association, classification accuracy, and clinical interpretability on patient level were reported.

RESULTS

Visual MTA scores showed excellent inter-rater agreement. Ordinal logistic regression and correlation analyses demonstrated robust associations between automated brain segmentations and visual MTA ratings, with the ILV/Hip ratio consistently outperforming individual hippocampal and ILV volumes. Pairwise classification accuracy showed good performance without statistically significant differences between the ILV/Hip ratio and visual MTA across disease stages, indicating potential interchangeability. Comparison to the normative population and clinical interpretability assessments showed commensurability in classifying MTA "severity" between visual MTA and ILV/Hip ratio measurements.

CONCLUSION

The ILV/Hip ratio shows the highest correlation to visual MTA, in comparison to automated individual ILV and hippocampal volumes, offering standardized measures for diagnostic support in different stages of cognitive decline.

Growth/differentiation factor 15 controls ependymal and stem cell number in the V-SVZ

The expression of growth/differentiation factor (GDF) 15 increases in the ganglionic eminence (GE) late in neural development, especially in neural stem cells (NSCs). However, GDF15 function in this region remains unknown. We report that GDF15 receptor is expressed apically in the GE and that GDF15 ablation promotes proliferation and cell division in the embryonic GE and in the adult ventricular-subventricular zone (V-SVZ). This causes a transient generation of additional neuronal progenitors, compensated by cell death, and a lasting increase in the number of ependymal cells and apical NSCs. Finally, both GDF15 receptor and the epidermal growth factor receptor (EGFR) were expressed in progenitors and mutation of GDF15 affected EGFR signaling. However, only exposure to exogenous GDF15, but not to EGF, normalized proliferation and the number of apical progenitors. Thus, GDF15 regulates proliferation of apical progenitors in the GE, thereby affecting the number of ependymal cells and NSCs.

Neonatal brain injury unravels transcriptional and signaling changes underlying the reactivation of cortical progenitors

Germinal activity persists throughout life within the ventricular-subventricular zone (V-SVZ) of the postnatal forebrain due to the presence of neural stem cells (NSCs). Accumulating evidence points to a recruitment for these cells following early brain injuries and suggests their amenability to manipulations. We used chronic hypoxia as a rodent model of early brain injury to investigate the reactivation of cortical progenitors at postnatal times. Our results reveal an increased proliferation and production of glutamatergic progenitors within the dorsal V-SVZ. Fate mapping of V-SVZ NSCs demonstrates their contribution to de novo cortical neurogenesis. Transcriptional analysis of glutamatergic progenitors shows parallel changes in methyltransferase 14 (Mettl14) and Wnt/β-catenin signaling. In agreement, manipulations through genetic and pharmacological activation of Mettl14 and the Wnt/β-catenin pathway, respectively, induce neurogenesis and promote newly-formed cell maturation. Finally, labeling of young adult NSCs demonstrates that pharmacological NSC activation has no adverse effects on the reservoir of V-SVZ NSCs and on their germinal activity.

Therapeutic hypothermia modulates the neurogenic response of the newborn piglet subventricular zone after hypoxia-ischemia

BACKGROUND

Neuroprotection combined with neuroregeneration may be critical for optimizing functional recovery in neonatal encephalopathy. To investigate the neurogenic response to hypoxia-ischemia (HI) followed by normothermia (38.5 °C) or three different hypothermic temperatures (35, 33.5, or 30 °C) in the subventricular zone (SVZ) of the neonatal piglet.

METHODS

Following transient cerebral HI and resuscitation, 28 newborn piglets were randomized to: normothermia or whole-body cooling to 35 °C, 33.5 °C, or 30 °C during 2-26 h (all n = 7). At 48 h, piglets were euthanized and SVZ obtained to evaluate its cellularity, pattern of cell death, radial glia length, doublecortin (DCX, neuroblasts) expression, and Ki67 (cell proliferation) and Ki67/Sox2 (neural stem/progenitor dividing) cell counts.

RESULTS

Normothermic piglets showed lower total (Ki67+) and neural stem/progenitor dividing (Ki67+Sox2+) cell counts when compared to hypothermic groups. Cooling to 33.5 °C obtained the highest values of SVZ cellularity, radial glia length processes, neuroblast chains area and DCX immunohistochemistry. Cooling to 30 °C, however, revealed decreased cellularity in the lateral SVZ and shorter radial glia processes when compared with 33.5 °C.

CONCLUSIONS

In a neonatal piglet model, hypothermia to 33.5 °C modulates the neurogenic response of the SVZ after HI, highlighting the potential beneficial effect of hypothermia to 33.5 °C on endogenous neurogenesis and the detrimental effect of overcooling beyond this threshold.

IMPACT

Neuroprotection combined with neuroregeneration may be critical for optimizing functional recovery in neonatal encephalopathy. Hypothermia may modulate neurogenesis in the subventricular zone (SVZ) of the neonatal hypoxic-ischemic piglet. Cooling to 33.5 °C obtained the highest values of SVZ cellularity, radial glia length processes, neuroblast chains area and doublecortin immunohistochemistry; cooling to 30 °C, however, revealed decreased cellularity and shorter radial glia processes. In a neonatal piglet model, therapeutic hypothermia (33.5 °C) modulates the neurogenic response of the SVZ after hypoxia-ischemia, highlighting also the detrimental effect of overcooling beyond this threshold.

Calculation of cerebral hemispheres volume values (grey matter, white matter and lateral ventricle) of sheep and goat: A stereological study

Stereology is a discipline that allows us to obtain quantitative information about the geometric structure of three-dimensional objects. In this study, the volume of grey matter (GM), white matter (WM), and lateral ventricle (LV) of the cerebral hemispheres (CH) in sheep and goats were calculated. For this purpose, six healthy male sheep and goat brains (1-2 years old) without any anomaly were used. Brains were fixed with 10% formaldehyde in the skull. The skull was opened using standard anatomical dissection methods, and the brains were carefully removed. Brain weight and volume were measured (using Archimedes' principle) after the meninges were removed. The cerebral hemispheres were separated from the other parts of the brain by a section made in front of the rostral colliculus. In the same way, the weight and volume of the cerebral hemispheres were measured. Afterward, the cerebral hemispheres were blocked with agar, and transversal cross sections (from rostral to caudal) with an average thickness of 3.42 mm were taken from the cerebral hemispheres. Grey matter was stained with Berlin blue macroscopic staining method. The stained cross sections were scanned at 600 dpi resolution, and a point counting grid was placed on the images with the ImageJ software. Cavalieri's principle calculated the surface area and volume measurements of the grey matter, white matter, and lateral ventricle. GM, WM, and LV volumes in sheep and goat cerebral hemispheres were calculated as 54.94, 21.48 and 3.06 mL in sheep, 57.46, 24.13 and 3.12 mL in goats, respectively. The percentages of these structures in the total hemisphere volume were 71.83%, 28.17% and 4.00% in sheep, 70.42%, 29.58% and 3.82% in goats, respectively. Asymmetry was not observed in cerebral hemispheres in both species. A difference was found in the WM, LV and LV: CH ratios in the right/left comparison of the goat (p < 0.05). In comparing sheep and goats, a significant difference was observed in WM right, WM left, WM total, CH left and CH total (p < 0.05). In conclusion, the cerebral hemispheres' grey matter and white matter ratio are frequently used to diagnose neurodegenerative diseases. In recent years, the increase in neurodegenerative disease models in farm animals has been enormous. It is thought that these values obtained from healthy animals in the current study will be important for such experimental studies in the future.

Astrocyte-derived extracellular vesicles inhibit the abnormal activation of immune function in neonatal mice with hypoxic-ischemic brain damage by carrying miR-124-3p

OBJECTIVE

Hypoxic-ischemic brain damage (HIBD) is among the leading causes of neonatal death worldwide. miR-124-3p can be utilized as a potential diagnostic and prognostic biomarker for perinatal asphyxia and HI encephalopathy in newborns. This study investigated the protective effect and mechanism of miR-124-3p in astrocyte-derived extracellular vesicles (ADEVs) in HIBD.

METHODS

    The neonatal mouse model of HIBD was established. Astrocytes were transfected with the miR-124-3p inhibitor, followed by isolation and identification of ADEVs (ADEVs + inhi miR). HIBD mice were injected with ADEVs or ADEVs + inhi miR through the lateral ventricle, and neurological function was evaluated based on the modified neurological severity score (mNSS). The infarct volume of mice and the morphological modifications of neurons were observed by TTC staining and hematoxylin-eosin staining. The contents of SOD, GSH-Px, CAT, and MDA in the hippocampus were measured. The neuronal apoptosis, the activation of MPO+ neutrophils, NK cells, and CD3+ cells in CA1 region of the hippocampus was determined by means of TUNEL staining and immunofluorescence.

RESULTS

ADEVs alleviated HIBD in neonatal mice. ADEVs could intrinsically protect mice from HIBD by reducing oxidative stress and apoptosis in hippocampal tissue. ADEVs inhibited the positive expression of MPO+ neutrophils, NK cells, and CD3+ cells in HIBD neonatal mice. ADEVs inhibited the hippocampal immune cells by delivering miR-124-3p in neonatal HIBD mice.

CONCLUSION

ADEVs can inhibit the abnormal activation of immune function in HIBD by delivering miR-124-3p, thereby eliciting a protective effect on brain damage in neonatal mice.

Jedi-1/MEGF12-mediated phagocytosis controls the pro-neurogenic properties of microglia in the ventricular-subventricular zone

Microglia are the primary phagocytes in the central nervous system and clear dead cells generated during development or disease. The phagocytic process shapes the microglia phenotype, which affects the local environment. A unique population of microglia resides in the ventricular-subventricular zone (V-SVZ) of neonatal mice, but how they influence the neurogenic niche is not well understood. Here, we demonstrate that phagocytosis contributes to a pro-neurogenic microglial phenotype in the V-SVZ and that these microglia phagocytose apoptotic cells via the engulfment receptor Jedi-1. Deletion of Jedi-1 decreases apoptotic cell clearance, triggering a neuroinflammatory microglia phenotype that resembles dysfunctional microglia in neurodegeneration and aging and that reduces neural precursor proliferation via elevated interleukin-1β signaling; interleukin-1 receptor inhibition rescues precursor proliferation in vivo. Together, these results reveal a critical role for Jedi-1 in connecting microglial phagocytic activity to the maintenance of a pro-neurogenic phenotype in the developing V-SVZ.

Unravelling a novel role for cannabidivarin in the modulation of subventricular zone postnatal neurogenesis

Postnatal neurogenesis has been shown to rely on the endocannabinoid system. Here we aimed at unravelling the role of Cannabidivarin (CBDV), a non-psychoactive cannabinoid, with high affinity for the non-classical cannabinoid receptor TRPV1, on subventricular zone (SVZ) postnatal neurogenesis. Using the neurosphere assay, SVZ-derived neural stem/progenitor cells (NSPCs) were incubated with CBDV and/or 5'-Iodoresinferotoxin (TRPV1 antagonist), and their role on cell viability, proliferation, and differentiation were dissected. CBDV was able to promote, through a TRPV1-dependent mechanism, cell survival, cell proliferation and neuronal differentiation. Furthermore, pulse-chase experiments revealed that CBDV-induced neuronal differentiation was a result of cell cycle exit of NSPCs. Regarding oligodendrocyte differentiation, CBDV inhibited oligodendrocyte differentiation and maturation. Since our data suggested that the CBDV-induced modulation of NSPCs acted via TRPV1, a sodium-calcium channel, and that intracellular calcium levels are known regulators of NSPCs fate and neuronal maturation, single cell calcium imaging was performed to evaluate the functional response of SVZ-derived cells. We observed that CBDV-responsive cells displayed a two-phase calcium influx profile, being the initial phase dependent on TRPV1 activation. Taken together, this work unveiled a novel and untapped neurogenic potential of CBDV via TRPV1 modulation. These findings pave the way to future neural stem cell biological studies and repair strategies by repurposing this non-psychoactive cannabinoid as a valuable therapeutic target.

Olfactory bulb neurogenesis depending on signaling in the subventricular zone

Olfaction is a crucial sense that is essential for the well-being and survival of individuals. Olfactory bulb (OB) is the first olfactory relay station, and its function depends on newly generated neurons from the subventricular zone (SVZ). These newly born neurons constantly migrate through the rostral migratory stream to integrate into existing neural networks within the OB, thereby contributing to olfactory information processing. However, the mechanisms underlying the contribution of SVZ adult neurogenesis to OB neurogenesis remain largely elusive. Adult neurogenesis is a finely regulated multistep process involving the proliferation of adult neural stem cells (aNSCs) and neural precursor cells, as well as the migration and differentiation of neuroblasts, and integration of newly generated neurons into preexisting neuronal circuitries. Recently, extensive studies have explored the mechanism of SVZ and OB neurogenesis. This review focused on elucidating various molecules and signaling pathways associated with OB neurogenesis dependent on the SVZ function. A better understanding of the mechanisms underlying the OB neurogenesis on the adult brain is an attractive prospect to induce aNSCs in SVZ to generate new neurons to ameliorate olfactory dysfunction that is involved in various diseases. It will also contribute to developing new strategies for the human aNSCs-based therapies.

Subventricular zone cytogenesis provides trophic support for neural repair in a mouse model of stroke

Stroke enhances proliferation of neural precursor cells within the subventricular zone (SVZ) and induces ectopic migration of newborn cells towards the site of injury. Here, we characterize the identity of cells arising from the SVZ after stroke and uncover a mechanism through which they facilitate neural repair and functional recovery. With genetic lineage tracing, we show that SVZ-derived cells that migrate towards cortical photothrombotic stroke in mice are predominantly undifferentiated precursors. We find that ablation of neural precursor cells or conditional knockout of VEGF impairs neuronal and vascular reparative responses and worsens recovery. Replacement of VEGF is sufficient to induce neural repair and recovery. We also provide evidence that CXCL12 from peri-infarct vasculature signals to CXCR4-expressing cells arising from the SVZ to direct their ectopic migration. These results support a model in which vasculature surrounding the site of injury attracts cells from the SVZ, and these cells subsequently provide trophic support that drives neural repair and recovery.

Neonatal Exposure to Lipopolysaccharide Promotes Neurogenesis of Subventricular Zone Progenitors in the Developing Neocortex of Ferrets

Lipopolysaccharide (LPS) is a natural agonist of toll-like receptor 4 that serves a role in innate immunity. The current study evaluated the LPS-mediated regulation of neurogenesis in the subventricular zone (SVZ) progenitors, that is, the basal radial glia and intermediate progenitors (IPs), in ferrets. Ferret pups were subcutaneously injected with LPS (500 μg/g of body weight) on postnatal days (PDs) 6 and 7. Furthermore, 5-ethynyl-2'-deoxyuridine (EdU) and 5-bromo-2'-deoxyuridine (BrdU) were administered on PDs 5 and 7, respectively, to label the post-proliferative and proliferating cells in the inner SVZ (iSVZ) and outer SVZ (oSVZ). A significantly higher density of BrdU single-labeled proliferating cells was observed in the iSVZ of LPS-exposed ferrets than in controls but not in post-proliferative EdU single-labeled and EdU/BrdU double-labeled self-renewing cells. BrdU single-labeled cells exhibited a lower proportion of Tbr2 immunostaining in LPS-exposed ferrets (22.2%) than in controls (42.6%) and a higher proportion of Ctip2 immunostaining in LPS-exposed ferrets (22.2%) than in controls (8.6%). The present findings revealed that LPS modified the neurogenesis of SVZ progenitors. Neonatal LPS exposure facilitates the proliferation of SVZ progenitors, followed by the differentiation of Tbr2-expressing IPs into Ctip2-expressing immature neurons.

Transfrontal External Ventricular Drainage Combined with OMMAYA Sac Implantation under Laser Navigation were Performed: A Technical Note

BACKGROUND

Hydrocephalus caused by spontaneous intracerebral hemorrhage (ICH) is an independent risk factor with adverse effects on the progression of the disease. Until now, the choice of intraventricular catheter placement and intraventricular fibrinolysis (IVF) has been mainly based on the personal experience of the neurosurgeon.

OBJECTIVE

We will introduce the clinical effect of the new external ventricular drainage (EVD), an independent innovation of our medical center, on ICH patients, hoping to inspire more neurosurgeons to apply our method.

METHODS

In this open retrospective study, We analyzed the clinical data, radiological manifestations, and prognostic scores of 10 patients with the spontaneous intracerebral hemorrhage who received transfrontal lateral ventricle puncture and drainage under laser navigation in our hospital.

RESULTS

A total of 10 patients with an average age of 58.10±9.97 years were enrolled for emergency surgery. All operations were completed according to the consensus specifications. It took 11.25±3.81 days for the intracranial pressure to return to normal. On admission, patients had a median GCS of 10. The median preoperative GCS was 8. The median GCS at discharge score was 15. At discharge, the median NIHSS score was 4. After 6 months of follow-up, patients had a median NIHSS score of 4. At discharge, the median ADL score of patients was 85. After 6 months of follow-up, the median ADL score of the patients was 95.

CONCLUSION

In treating patients with ICH, the emergency treatment of transfrontal external ventricular drainage combined with OMMAYA sac implantation under laser navigation is a surgical method worthy of further study.

Treatment of hydrocephalus in an ovine model with an intraparenchymal stent

OBJECTIVE

While CSF diversion is highly effective at treating hydrocephalus, shunting is unfortunately associated with a very high revision rate. Studies have demonstrated that proximal catheter obstruction is a major cause of failure. A novel proximal access device was developed, and pilot testing was performed in a sheep model of hydrocephalus.

METHODS

Hydrocephalus was induced in 8 sheep using a cisternal injection of 4 ml of 25% kaolin, and the sheep were randomized to either a standard ventricular catheter or a novel intraparenchymal stent (IPS). Both groups received identical valves and distal catheters. The novel device included a 3D-printed stainless steel port and a 6 × 40-mm covered peripheral vascular stent. Animals were euthanized for signs of hydrocephalus or at a time point of 2 months. MRI was performed to determine ventricular size. Time to failure and Evans indices were compared using the Wilcoxon rank-sum test.

RESULTS

All 4 experimental devices were placed without difficulty into the right lateral ventricle. There was a trend toward longer survival in the experimental group (40 vs 26 days, p = 0.24). Within the IPS group, 3 of the 4 sheep did not experience clinical symptoms of shunt failure and had an average of 37% decrease in Evans index. While 3 of 4 traditional proximal catheters demonstrated debris within the inlet holes, there was no obstructive material found in the IPSs.

CONCLUSIONS

An IPS was successfully used to treat hydrocephalus in a sheep model. While statistical significance was not achieved, there were clear benefits to using a stent, including a decreased clog rate and the ability to perform a percutaneous revision. Further testing is needed to ensure efficacy and safety prior to human application.

Revisiting the transorbital approach for emergency external ventricular drainage: an anatomical study of relevant parameters and their effect on the effectiveness of using Tubbs' point

The transorbital approach (TOA) can provide immediate access to the lateral ventricles by piercing the roof of the orbit (ROO) with a spinal needle and without the need of a drill. Reliable external landmarks for the TOA ventriculostomy have been described, however, the necessary spinal needle gauge and other relevant parameters such as the thickness of the ROO have not been evaluated. Nineteen formalin-fixed adult cadaveric heads underwent the TOA. Spinal needles of different gauges were consecutively used in each specimen beginning with the smallest gauge until the ROO was successfully pierced. The thickness of the ROO at the puncture site and around its margins was measured. Other parameters were also measured. The TOA was successfully performed in 14 cases (73.68%), where the most suitable needle gauge was 13 (47.37%), followed by a 10-gauge needle (36.84%). The mean thickness of the ROO at the puncture site, and the mean length of the needle to the puncture site were 1.7 mm (range 0.2-3.4 mm) and 15.5 mm (range 9.2-23.4 mm), respectively. A ROO thickness of greater than 2.0 mm required a 10-gauge needle in seven cases, and in five cases, a 10-gauge needle was not sufficient for piercing the ROO. The presence of hyperostosis frontalis interna (HFI) (21.05%) was related to the failure of this procedure (80%; p < 0.00). Using a 13/10-gauge spinal needle at Tubbs' point for TOA ventriculostomy allowed for external ventricular access in most adult specimens. The presence of HFI can hinder this procedure. These findings are important when TOA ventriculostomy is considered.

Isolated entrapment of the lateral ventricle after neuroendoscopic resection of colloid cysts: single - center experience and management

BACKGROUND

A minimally invasive option of colloid cyst surgical treatment is endoscopic resection, well validated in various reports and clinical practice. A rare complication of the surgical treatment, previously reported only once in literature, is the entrapment of the lateral ventricle. In this study we aim to outline our experience in the management of this occurrence, hypothesizing possible etiopathogenetic causes.

METHODS

Among patients who underwent neuroendoscopic resection for a colloid cysts at our Institution between 2013 and 2022, cases who developed a postoperative lateral ventricle entrapment were retrospectively reviewed and included. Clinical history, imaging and treatment were reported.

RESULTS

Among 34 patients treated for a colloid cysts, two (5.9 %) patients developed an ipsilateral ventricular entrapment with dilation from two to five months after the resection. Both patients were substantially asymptomatic and neurologically intact, and therefore treated conservatively. One case underwent complete spontaneous radiological resolution one month later, and the other one has remained neurological asymptomatic at follow-up.

CONCLUSIONS

Isolated asymptomatic ventricular entrapment with significant dilation after endoscopic colloid cyst resection is a rare occurrence which can be plausibly caused by scar tissue at the level of the foramen of Monro. Because they can have an indolent course with spontaneous resolution, conservative treatment is a viable option, with strict radiological and clinical follow - up. Given the rarity of the occurrence, further studies with larger cohorts are warranted to confirm the etiopathogenetic hypothesis and validate the clinical management.

Cortical regulation of neurogenesis and cell proliferation in the ventral subventricular zone

Neurogenesis and differentiation of neural stem cells (NSCs) are controlled by cell-intrinsic molecular pathways that interact with extrinsic signaling cues. In this study, we identify a circuit that regulates neurogenesis and cell proliferation in the lateral ventricle-subventricular zone (LV-SVZ). Our results demonstrate that direct glutamatergic projections from the anterior cingulate cortex (ACC), as well as inhibitory projections from calretinin+ local interneurons, modulate the activity of cholinergic neurons in the subependymal zone (subep-ChAT+). Furthermore, in vivo optogenetic stimulation and inhibition of the ACC-subep-ChAT+ circuit are sufficient to control neurogenesis in the ventral SVZ. Both subep-ChAT+ and local calretinin+ neurons play critical roles in regulating ventral SVZ neurogenesis and LV-SVZ cell proliferation.

Connexin 43-mediated neurovascular interactions regulate neurogenesis in the adult brain subventricular zone

The subventricular zone (SVZ) is the largest neural stem cell (NSC) niche in the adult brain; herein, the blood-brain barrier is leaky, allowing direct interactions between NSCs and endothelial cells (ECs). Mechanisms by which direct NSC-EC interactions in the adult SVZ control NSC behavior are unclear. We found that Cx43 is highly expressed by SVZ NSCs and ECs, and its deletion in either leads to increased NSC proliferation and neuroblast generation, suggesting that Cx43-mediated NSC-EC interactions maintain NSC quiescence. This is further supported by single-cell RNA sequencing and in vitro studies showing that ECs control NSC proliferation by regulating expression of genes associated with NSC quiescence and/or activation in a Cx43-dependent manner. Cx43 mediates these effects in a channel-independent manner involving its cytoplasmic tail and ERK activation. Such insights inform adult NSC regulation and maintenance aimed at stem cell therapies for neurodegenerative disorders.

High-efficiency pharmacogenetic ablation of oligodendrocyte progenitor cells in the adult mouse CNS

Approaches to investigate adult oligodendrocyte progenitor cells (OPCs) by targeted cell ablation in the rodent CNS have limitations in the extent and duration of OPC depletion. We have developed a pharmacogenetic approach for conditional OPC ablation, eliminating >98% of OPCs throughout the brain. By combining recombinase-based transgenic and viral strategies for targeting OPCs and ventricular-subventricular zone (V-SVZ)-derived neural precursor cells (NPCs), we found that new PDGFRA-expressing cells born in the V-SVZ repopulated the OPC-deficient brain starting 12 days after OPC ablation. Our data reveal that OPC depletion induces V-SVZ-derived NPCs to generate vast numbers of PDGFRA+NG2+ cells with the capacity to proliferate and migrate extensively throughout the dorsal anterior forebrain. Further application of this approach to ablate OPCs will advance knowledge of the function of both OPCs and oligodendrogenic NPCs in health and disease.

Microglia Maintain Homeostatic Conditions in the Developing Rostral Migratory Stream

Microglia invade the neuroblast migratory corridor of the rostral migratory stream (RMS) early in development. The early postnatal RMS does not yet have the dense astrocyte and vascular scaffold that helps propel forward migrating neuroblasts, which led us to consider whether microglia help regulate conditions permissive to neuroblast migration in the RMS. GFP-labeled microglia in CX3CR-1GFP/+ mice assemble primarily along the outer borders of the RMS during the first postnatal week, where they exhibit predominantly an ameboid morphology and associate with migrating neuroblasts. Microglia ablation for 3 d postnatally does not impact the density of pulse labeled BrdU+ neuroblasts nor the distance migrated by tdTomato electroporated neuroblasts in the RMS. However, microglia wrap DsRed-labeled neuroblasts in the RMS of P7 CX3CR-1GFP/+;DCXDsRed/+ mice and express the markers CD68, CLEC7A, MERTK, and IGF-1, suggesting active regulation in the developing RMS. Microglia depletion for 14 d postnatally further induced an accumulation of CC3+ DCX+ apoptotic neuroblasts in the RMS, a wider RMS and extended patency of the lateral ventricle extension in the olfactory bulb. These findings illustrate the importance of microglia in maintaining a healthy neuroblast population and an environment permissive to neuroblast migration in the early postnatal RMS.

[Chordoid gliomas of the third ventricle]

BACKGROUND

Chordoid glioma is a rare slow-growing tumor of the central nervous system. Available world experience includes no more than 200 cases (lesion of the third ventricle in absolute majority of cases). Recognition and treatment of chordoid glioma are currently difficult problems due to small incidence of this disease.

OBJECTIVE

To describe clinical manifestations and surgical treatment of chordoid glioma of the third ventricle considering literature data and own experience.

MATERIAL AND METHODS

There were 12 patients (6 men and 6 women) with chordoid glioma between 2004 and 2023 (10 patients with lesion of the third ventricle, 1 - lateral ventricle, 1 - pineal region). Only patients with tumors of the third ventricle were analyzed.

RESULTS

Total and subtotal resection was performed in 1 and 3 cases, respectively. Five patients underwent partial resection, 1 patient underwent biopsy. The follow-up data were available in 7 out of 10 patients (mean 25 months). Radiotherapy was performed in 4 patients (continued tumor growth in 2 cases). One patient died.

CONCLUSION

Chordoid glioma is a benign tumor predominantly localized in the third ventricle. Preoperative MRI and CT in some cases make it possible to suspect chordoid glioma and differentiate this tumor from craniopharyngioma, meningioma and pituitary adenoma by such signs as isointense signal in T1WI, hyper- or isointense signal in T2WI, homogeneous contrast enhancement and edema of basal ganglia in T2 FLAIR images. The only effective treatment for chordoid glioma is surgery. Total resection is often impossible or extremely dangerous due to location of tumor, large size and invasion of the third ventricle. Postoperative mental disorders and diabetes insipidus, including severe hypernatremia, are common that requires mandatory monitoring of water and electrolyte balance.

Synergistic effects of hIAPP and Aβ1-42 impaired the olfactory function associated with the decline of adult neurogenesis in SVZ

According to many in the field，the prevalence of Alzheimer's disease (AD) in type II diabetes (T2DM) populations is considerably higher than that in the normal population. Human islet amyloid polypeptide (hIAPP) is considered to be a common risk factor for T2DM and AD. Preliminary observations around T2DM animal model show that the decrease of adult neural stem cells (NSCs) in the subventricular zone (SVZ) is accompanied by olfactory dysfunction. Furthermore, impaired olfactory function could serve as to an early predictor of neurodegeneration，which is associated with cognitive impairment. However, the synergistic effects between hIAPP and amyloid-beta (Aβ) _1-42 in the brain and the neurodegeneration remains to be further clarified. In this study, olfactory capacity, synaptic density, status of NSC in SVZ, and status of newborn neurons in olfactory bulb (OB) were assessed 6 months after stereotactic injection of oligomer Aβ_1-42 into the dens gyrus (DG) of hIAPP-/+ mice or wild-type homogenous mice. Our results set out that Aβ₄₂ and amylin co-localized into OB and raised Aβ₄₂ deposition in hIAPP^-/+ mice compared with wild-type brood mice. In addition, 6 months after injection of Aβ_1-42 in hIAPP^-/+ mice, these mice showed increased olfactory dysfunction, significant loss of synapses, depletion of NSC in SVZ, and impaired cell renewal in OB. Our present study suggested that the synergistic effects between hIAPP and Aβ_1-42 impairs olfactory function and was associated with decreased neurogenesis in adults with SVZ.

Current Understanding of the Neural Stem Cell Niches

Neural stem cells (NSCs) are self-renewing, multipotent cells which give rise to all components of the central nervous system (CNS) during embryogenesis, but also activate in response to injury and disease and maintain a certain level of neurogenic activity throughout adulthood. This activity takes place in specialized regions of the brain, the neurovascular niches, whose main role is to control the behaviour of the CNS. In adult mammals, two main “canonical” niches have been described: The subventricular zone (SVZ) of the lateral ventricles and the subgranular zone (SGZ) of the dentate gyrus. This review discusses our current understanding of the neural stem cells and their canonical niches, as well as their structure, behaviours, and role in neural disease.

Copper Modulates Adult Neurogenesis in Brain Subventricular Zone

The subventricular zone (SVZ) in lateral ventricles is the largest neurogenic region in adult brain containing high amounts of copper (Cu). This study aims to define the role of Cu in adult neurogenesis by chelating labile Cu ions using a well-established Cu chelator D-Penicillamine (D-Pen). A neurosphere model derived from adult mouse SVZ tissues was established and characterized for its functionality with regards to neural stem/progenitor cells (NSPCs). Applying D-Pen in cultured neurospheres significantly reduced intracellular Cu levels and reversed the Cu-induced suppression of NSPC’s differentiation and migration. An in vivo intracerebroventricular (ICV) infusion model was subsequently established to infuse D-Pen directly into the lateral ventricle. Metal analyses revealed a selective reduction of Cu in SVZ by 13.1% (p = 0.19) and 21.4% (p < 0.05) following D-Pen infusions at low (0.075 μg/h) and high (0.75 μg/h) doses for 28 days, respectively, compared to saline-infused controls. Immunohistochemical studies revealed that the 7-day, low-dose D-Pen infusion significantly increased Ki67(+)/Nestin(+) cell counts in SVZ by 28% (p < 0.05). Quantification of BrdU(+)/doublecortin (DCX)(+) newborn neuroblasts in the rostral migration stream (RMS) and olfactory bulb (OB) further revealed that the short-term, low-dose D-Pen infusion, as compared with saline-infused controls, resulted in more newborn neuroblasts in OB, while the high-dose D-Pen infusion showed fewer newborn neuroblasts in OB but with more arrested in the RMS. Long-term (28-day) infusion revealed similar outcomes. The qPCR data from neurosphere experiments revealed altered expressions of mRNAs encoding key proteins known to regulate SVZ adult neurogenesis, including, but not limited to, Shh, Dlx2, and Slit1, in response to the changed Cu level in neurospheres. Further immunohistochemical data indicated that Cu chelation also altered the expression of high-affinity copper uptake protein 1 (CTR1) and metallothionein-3 (MT3) in the SVZ as well as CTR1 in the choroid plexus, a tissue regulating brain Cu homeostasis. Taken together, this study provides first-hand evidence that a high Cu level in SVZ appears likely to maintain the stability of adult neurogenesis in this neurogenic zone.

Hydrocephalus in Nfix−/− Mice Is Underpinned by Changes in Ependymal Cell Physiology

Nuclear factor one X (NFIX) is a transcription factor required for normal ependymal development. Constitutive loss of Nfix in mice (Nfix−/−) is associated with hydrocephalus and sloughing of the dorsal ependyma within the lateral ventricles. Previous studies have implicated NFIX in the transcriptional regulation of genes encoding for factors essential to ependymal development. However, the cellular and molecular mechanisms underpinning hydrocephalus in Nfix−/− mice are unknown. To investigate the role of NFIX in hydrocephalus, we examined ependymal cells in brains from postnatal Nfix−/− and control (Nfix+/+) mice using a combination of confocal and electron microscopy. This revealed that the ependymal cells in Nfix−/− mice exhibited abnormal cilia structure and disrupted localisation of adhesion proteins. Furthermore, we modelled ependymal cell adhesion using epithelial cell culture and revealed changes in extracellular matrix and adherens junction gene expression following knockdown of NFIX. Finally, the ablation of Nfix from ependymal cells in the adult brain using a conditional approach culminated in enlarged ventricles, sloughing of ependymal cells from the lateral ventricles and abnormal localisation of adhesion proteins, which are phenotypes observed during development. Collectively, these data demonstrate a pivotal role for NFIX in the regulation of cell adhesion within ependymal cells of the lateral ventricles.

Single-Cell and Single-Nucleus RNAseq Analysis of Adult Neurogenesis

The complexity of adult neurogenesis is becoming increasingly apparent as we learn more about cellular heterogeneity and diversity of the neurogenic lineages and stem cell niches within the adult brain. This complexity has been unraveled in part due to single-cell and single-nucleus RNA sequencing (sc-RNAseq and sn-RNAseq) studies that have focused on adult neurogenesis. This review summarizes 33 published studies in the field of adult neurogenesis that have used sc- or sn-RNAseq methods to answer questions about the three main regions that host adult neural stem cells (NSCs): the subventricular zone (SVZ), the dentate gyrus (DG) of the hippocampus, and the hypothalamus. The review explores the similarities and differences in methodology between these studies and provides an overview of how these studies have advanced the field and expanded possibilities for the future.

Neurogenesis of Subventricular Zone Progenitors in the Premature Cortex of Ferrets Facilitated by Neonatal Valproic Acid Exposure

The present study evaluated the neurogenesis of neonatal valproic acid (VPA) exposure on subventricular zone progenitors of the developing cerebral cortex in ferrets. VPA was injected at a dose of 200 µg/g of body weight into ferret infants on postnatal days 6 and 7. Two different thymidine analogues, 5-ethynyl-2′-deoxyuridine (EdU) and 5-bromo-2′-deoxyuridine (BrdU), were injected with a 48 h interval to label proliferating cells before and after VPA exposure. Two hours after BrdU injection, BrdU single- and EdU/BrdU double-labeled cells, but not EdU single-labeled cells, were significantly denser in both the inner and outer subventricular zones of VPA-exposed infants than in control infants. Notably, more than 97% of BrdU single- and EdU/BrdU double-labeled cells were immunopositive for Pax6, a stable marker for basal radial glia (bRG), in both groups. In contrast, the percentage of cells positively immunostained for Cux1, a postmitotic marker for upper-layer cortical neurons, in both EdU single- and BrdU single-labeled cells, was significantly higher in VPA-exposed infants than in control infants. These findings suggest that neonatal VPA exposure facilitates bRG proliferation, including self-renewal, followed by their differentiation into upper layer cortical neurons in the premature cortex of ferrets.

Impact of physiological factors on longitudinal structural MRI measures of the brain

Longitudinal MRI is used in clinical research studies to examine illness progression, neurodevelopment, and the effect of medical interventions. Such studies typically report changes in brain volume of less than 5%. However, there is a concern that these findings could be obscured or confounded by small changes in brain volume estimates caused by physiological factors such as, dehydration, blood pressure, caffeine levels, and circadian rhythm. In this study, MRI scans using the ADNI-III protocol were acquired from 20 participants (11 female) at two time points (mean interval = 20.3 days). Hydration, systolic and diastolic blood pressure, caffeine intake, and time of day were recorded at both visits. Images were processed using FreeSurfer. Three a priori hypothesised brain regions (hippocampus, lateral ventricles, and total brain) were selected, and an exploratory analysis was conducted on FreeSurfer's auto-segmented brain regions. There was no significant effect of the physiological factors on changes in the hypothesised brain regions. We provide estimates for the maximum percentage change in regional brain volumes that could be expected to occur from normal variation in each of the physiological measures. In this study, normal variations in physiological parameters did not have a detectable effect on longitudinal changes in brain volume.

Heterogeneity of quiescent and active neural stem cells in the postnatal brain

In the postnatal mammalian brain, neurogenic activity is retained in anatomically restricted areas, driven by pools of Neural Stem Cells (NSCs). These cells and their progeny have been studied intensively as potential targets for regenerative treatments, aiming at either their in situ manipulation or their use as sources of cells for transplantation-based strategies. Although their full identity, heterogeneity and differentiation potential remain elusive, due to the absence of specific cell-type markers, our knowledge of their properties is constantly expanding. Here, we focus on the NSC niche that is located at the Subependymal Zone (SEZ/ also known as Subventricular Zone) of the lateral ventricles of the brain. We review, summarize and explain the different faces of the NSC, as they have been described, using a wide range of experimental approaches, over a time-frame of three decades: the primitive, definitive, quiescent or activated NSC. We also review the growing evidence of the existence of latent NSCs outside of niches, in the brain parenchyma, that constitute promising new therapeutic targets, complemented by the novel technologies of in vivo cell reprogramming.

Adult human neurogenesis: early studies clarify recent controversies and go further

Evidence on adult mammalian neurogenesis and scarce studies with human brains led to the idea that adult human neurogenesis occurs in the subgranular zone (SGZ) of the dentate gyrus and in the subventricular zone (SVZ). However, findings published from 2018 rekindled controversies on adult human SGZ neurogenesis. We systematically reviewed studies published during the first decade of characterization of adult human neurogenesis (1994-2004) - when the two-neurogenic-niche concept in humans was consolidated - and compared with further studies. The synthesis of both periods is that adult human neurogenesis occurs in an intensity ranging from practically zero to a level comparable to adult mammalian neurogenesis in general, which is the prevailing conclusion. Nonetheless, Bernier and colleagues showed in 2000 intriguing indications of adult human neurogenesis in a broad area including the limbic system. Likewise, we later showed evidence that limbic and hypothalamic structures surrounding the circumventricular organs form a continuous zone expressing neurogenesis markers encompassing the SGZ and SVZ. The conclusion is that publications from 2018 on adult human neurogenesis did not bring novel findings on location of neurogenic niches. Rather, we expect that the search of neurogenesis beyond the canonical adult mammalian neurogenic niches will confirm our indications that adult human neurogenesis is orchestrated in a broad brain area. We predict that this approach may, for example, clarify that human hippocampal neurogenesis occurs mostly in the CA1-subiculum zone and that the previously identified human rostral migratory stream arising from the SVZ is indeed the column of the fornix expressing neurogenesis markers.

Isolation of Adult Mouse Neural Stem Cells and Assessment of Self-Renewal by ELDA

The generation of new neurons in the adult brain throughout life is integral to brain plasticity and repair. Adult neural stem cells (aNSCs), present in the subventricular zone (SVZ) of the lateral ventricle wall and the subgranular zone (SGZ) of the hippocampal dentate gyrus, divide symmetrically or asymmetrically to maintain the stem cell pool or become committed progenitors and differentiate into various cell lineages. Depletion or dysregulation of aNSCs impairs proper brain connectivity and function and can contribute to several brain diseases including cognitive and neurodegenerative disorders and brain cancer. In this chapter, we present our optimized method to obtain and maintain reproducible neurosphere cultures from the adult mouse brain followed by evaluation of self-renewal using the extreme limiting dilution assay (ELDA) software. We use this assay routinely on aNSCs obtained from patient mouse models to generate log fraction plots and provide confidence intervals for all limiting dilution assay (LDA) data. At the same time, given the low number of NSCs required for the completion of the ELDA experiment, it is feasible to employ this approach to conduct high-content compound screening for therapeutic interventions aimed at enhancing the stem cell pool or combating a cohort of genetic and epigenetic disorders.

Multidisciplinary treatment of primary intracranial yolk sac tumor: A case report and literature review

RATIONALE

Intracranial yolk sac tumors (YSTs) are rare malignancies with limited treatment options and a dismal prognosis. They are usually managed with surgical resection and chemoradiotherapy.

PATIENT CONCERNS

Here, we report a patient with primary YST in the pineal region who achieved long term survival. Despite undergoing treatment, he experienced several recurrences over a 15-year period.

DIAGNOSIS

Brain magnetic resonance imaging (MRI) demonstrated the presence of space-occupying lesions in the pineal region and the medial tail of the left lateral ventricle. The tumors were excised, and the histological diagnosis suggested an intracranial YST.

INTERVENTIONS

The patient achieved long term survival after combined modality therapy including surgery, stereotactic radiosurgery (SRS)/intensity modulated radiation therapy (IMRT), chemotherapy, and targeted therapy.

OUTCOMES

The disease remained stable. However, the patient gave up treatment and passed away in October 2020, with a total survival of about 15 years.

LESSONS

To the best of our knowledge, this patient with intracranial YST had received a longer survival compared with other published reports. We summarize previously published reports of intracranial YST and discuss the importance of multidisciplinary treatment. SRS may have a role, as a focal boost to residual tumor after resection or in case of recurrence after conventional radiotherapy, in the multimodality management of intracranial YSTs.

An Overview of Adult Neurogenesis

Neurogenesis is maintained in the mammalian brain throughout adulthood in two main regions: the subventricular zone (SVZ) of the lateral ventricles and the subgranular zone (SGZ) of the hippocampal dentate gyrus. Adult neurogenesis is a process composed of multiple steps by which neurons are generated from dividing adult neural stem cells and migrate to be integrated into existing neuronal circuits. Alterations in any of these steps impair neurogenesis and may compromise brain function, leading to cognitive impairment and neurodegenerative diseases. Therefore, understanding the cellular and molecular mechanisms that modulate adult neurogenesis is the centre of attention of regenerative research. In this chapter, we review the main properties of the adult neurogenic niches.

Brain-synthesized oestrogens regulate cortical migration in a sexually divergent manner

Oestrogens play an important role in brain development where they have been implicated in controlling various cellular processes. Several lines of evidence have been presented showing that oestrogens can be synthesized locally within the brain. Studies have demonstrated that aromatase, the enzyme responsible for the conversion of androgens to oestrogens, is expressed during early development in both male and female cortices. Furthermore, 17β-oestradiol has been measured in foetal brain tissue from multiple species. 17β-oestradiol regulates neural progenitor proliferation as well as the development of early neuronal morphology. However, what role locally derived oestrogens play in regulating cortical migration and, moreover, whether these effects are the same in males and females are unknown. Here, we investigated the impact of knockdown expression of Cyp19a1, which encodes aromatase, between embryonic day (E) 14.5 and postnatal day 0 (P0) had on neural migration within the cortex. Aromatase was expressed in the developing cortex of both sexes, but at significantly higher levels in male than female mice. Under basal conditions, no obvious differences in cortical migration between male and female mice were observed. However, knockdown of Cyp19a1 resulted in an increase in cells within the cortical plate, and a concurrent decrease in the subventricular zone/ventricular zone in P0 male mice. Interestingly, the opposite effect was observed in females, who displayed a significant reduction in cells migrating to the cortical plate. Together, these findings indicate that brain-derived oestrogens regulate radial migration through distinct mechanisms in males and females.

Cell Progeny in the Olfactory Bulb After Targeting Specific Progenitors with Different UbC-StarTrack Approaches

The large phenotypic variation in the olfactory bulb may be related to heterogeneity in the progenitor cells. Accordingly, the progeny of subventricular zone (SVZ) progenitor cells that are destined for the olfactory bulb is of particular interest, specifically as there are many facets of these progenitors and their molecular profiles remain unknown. Using modified StarTrack genetic tracing strategies, specific SVZ progenitor cells were targeted in E12 mice embryos, and the cell fate of these neural progenitors was determined in the adult olfactory bulb. This study defined the distribution and the phenotypic diversity of olfactory bulb interneurons from specific SVZ-progenitor cells, focusing on their spatial pallial origin, heterogeneity, and genetic profile.

[High Parietal Paramedian Approach for Tumors in the Trigone of the Lateral Ventricle:Technical Nuances and Case Review]

The aim of this paper was to introduce and validate our high parietal paramedian approach for tumors in the trigone of the lateral ventricles. This study included nine tumors found in the trigone region and treated surgically in our institute. The approach of this method is described here. First, the central sulcus and post-central gyrus were identified by the electrodes after opening of the dura mater. Corticotomy was performed in the rearward area of the post-central gyrus 25mm within the midline and 20mm along the length, to avoid the damage to the primary sensory area and arcuate fasciculus. A round-shaped spatula was used to protect the surrounding brain tissue. The tumors were excised from medial portion because the feeding supply is usually derived from the medial and deep choroid plexus. As vital structures, including the optic radiation, thalamus, posterior horn of the internal capsule, and fornix, exist around the trigone, gentle dissection from the ventricle wall is needed. The hematoma was removed last to avoid obstructive hydrocephalus, and a drainage tube was left in the ventricle. Total gross resection of all the tumors was performed, and an approximate blood loss of 50-445ml(average 134.3ml)was recorded. None of the patients had permanent neurological deficit, and those with visual defects recovered postoperatively. Preservation of the visual and high brain function is an important consideration in the treatment strategy for tumors in the trigone of the lateral ventricle. The high parietal paramedian approach is a versatile and prominent approach that helps preserve these functions.

Neuronavigator-guided ventriculoscopic approach for symptomatic xanthogranuloma of the choroid plexus in the lateral ventricle

Xanthogranuloma of choroid plexus is an extremely rare, benign, and mostly asymptomatic intracranial lesion. We report a case of symptomatic lateral ventricular xanthogranuloma resected via a neuronavigator-guided ventriculoscopic approach. Then we review recent English medical literature and notice that craniotomies have been the most popular treatment. But our choice of a ventriculoscopic approach possesses unique advantages such as minimized neural tissue damage, shortened operative time, less blood loss, and safer access to central structures over conventional open surgeries. Informed consent has been obtained from the patient and his immediate family regarding this case report.

The role of inflammation in subventricular zone cancer

The adult subventricular zone (SVZ) stem cell niche has proven vital for discovering neurodevelopmental mechanisms and holds great potential in medicine for neurodegenerative diseases. Yet the SVZ holds a dark side - it can become tumorigenic. Glioblastomas can arise from the SVZ via cancer stem cells (CSCs). Glioblastoma and other brain cancers often have dismal prognoses since they are resistant to treatment. In this review we argue that the SVZ is susceptible to cancer because it contains stem cells, migratory progenitors and unusual inflammation. Theoretically, SVZ stem cells can convert to CSCs more readily than can postmitotic neural cells. Additionally, the robust long-distance migration of SVZ progenitors can be subverted upon tumorigenesis to an infiltrative phenotype. There is evidence that the SVZ, even in health, exhibits chronic low-grade cellular and molecular inflammation. Its inflammatory response to brain injuries and disease differs from that of other brain regions. We hypothesize that the SVZ inflammatory environment can predispose cells to novel mutations and exacerbate cancer phenotypes. This can be studied in animal models in which human mutations related to cancer are knocked into the SVZ to induce tumorigenesis and the CSC immune interactions that precede full-blown cancer. Importantly inflammation can be pharmacologically modulated providing an avenue to brain cancer management and treatment. The SVZ is accessible by virtue of its location surrounding the lateral ventricles and CSCs in the SVZ can be targeted with a variety of pharmacotherapies. Thus, the SVZ can yield aggressive tumors but can be targeted via several strategies.

9p24 triplication in syndromic hydrocephalus with diffuse villous hyperplasia of the choroid plexus

Hydrocephalus, a disorder of impaired cerebrospinal fluid (CSF) homeostasis, often results from an imbalance between CSF production and reabsorption. Rarely, hydrocephalus is the consequence of CSF hypersecretion in the context of diffuse villous hyperplasia of the choroid plexus (DVHCP). The limited genetic information in previously reported cases suggests a high prevalence of gains of Chromosome 9p in this disease, although the critical genes involved in DVHCP pathogenesis have not been identified. Here, we report a patient with syndromic hydrocephalus with DVHCP associated with a novel 9p24.3-11.2 triplication and 15q13.2-q13.3 microdeletion. We review the clinical, radiological, and pathological features of DVHCP, as well as its surgical management. A better understanding of the genetic basis of DVHCP could spur the development of rational, targeted nonsurgical hydrocephalus treatments.

In vivo distribution of U87MG cells injected into the lateral ventricle of rats with spinal cord injury

Stem cells could be the next generation therapeutic option for neurodegenerative diseases including spinal cord injury (SCI). However, several critical factors such as delivery method should be determined before their clinical applications. Previously, we have demonstrated that lateral ventricle (LV) injection as preclinical simulation could be used for intrathecal administration in clinical trials using rodent animal models. In this study, we further analyzed in vivo distribution of cells that were injected into LVs of rats with SCI at thoracic level using in vivo imaging techniques. When 5 × 10⁶ U87MG cells labelled with fluorescent magnetic nanoparticle (FMNP-labelled U87MG) were administrated into LVs at 7 days after SCI, FMNP-labelled U87MG cells were observed in all regions of the spinal cord at 24 hours after the injection. Compared to water-soluble Cy5.5 fluorescent dye or rats without SCI, in vivo distribution pattern of FMNP-labelled U87MG cells was not different, although migration to the spinal cord was significantly reduced in both Cy5.5 fluorescent dye and FMNP-labelled U87MG cells caused by the injury. The presence of FMNP-labelled U87MG cells in the spinal cord was confirmed by quantitative PCR for human specific sequence and immunohistochemistry staining using antibody against human specific antigen. These data indicate that LV injection could recapitulate intrathecal administration of stem cells for SCI patients. Results of this study might be applied further to the planning of optimal preclinical and clinical trials of stem cell therapeutics for SCI.

Blue light potentiates neurogenesis induced by retinoic acid-loaded responsive nanoparticles

Neurogenic niches constitute a powerful endogenous source of new neurons that can be used for brain repair strategies. Neuronal differentiation of these cells can be regulated by molecules such as retinoic acid (RA) or by mild levels of reactive oxygen species (ROS) that are also known to upregulate RA receptor alpha (RARα) levels. Data showed that neural stem cells from the subventricular zone (SVZ) exposed to blue light (405nm laser) transiently induced NADPH oxidase-dependent ROS, resulting in β-catenin activation and neuronal differentiation, and increased RARα levels. Additionally, the same blue light stimulation was capable of triggering the release of RA from light-responsive nanoparticles (LR-NP). The synergy between blue light and LR-NP led to amplified neurogenesis both in vitro and in vivo, while offering a temporal and spatial control of RA release. In conclusion, this combinatory treatment offers great advantages to potentiate neuronal differentiation, and provides an innovative and efficient application for brain regenerative therapies.

STATEMENT OF SIGNIFICANCE

Controlling the differentiation of stem cells would support the development of promising brain regenerative therapies. Blue light transiently increased reactive oxygen species, resulting in neuronal differentiation and increased retinoic acid receptor (RARα) levels. Additionally, the same blue light stimulation was capable of triggering the release of RA from light-responsive nanoparticles (LR-NP). The synergy between blue light and LR-NP led to amplified neurogenesis, while offering a temporal and spatial control of RA release. In this sense, our approach relying on the modulation of endogenous stem cells for the generation of new neurons may support the development of novel clinical therapies.

Adeno-associated virus-delivered artificial microRNA extends survival and delays paralysis in an amyotrophic lateral sclerosis mouse model

OBJECTIVE

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease characterized by loss of motor neurons, resulting in progressive muscle weakness, paralysis, and death within 5 years of diagnosis. About 10% of cases are inherited, of which 20% are due to mutations in the superoxide dismutase 1 (SOD1) gene. Riluzole, the only US Food and Drug Administration-approved ALS drug, prolongs survival by only a few months. Experiments in transgenic ALS mouse models have shown decreasing levels of mutant SOD1 protein as a potential therapeutic approach. We sought to develop an efficient adeno-associated virus (AAV)-mediated RNAi gene therapy for ALS.

METHODS

A single-stranded AAV9 vector encoding an artificial microRNA against human SOD1 was injected into the cerebral lateral ventricles of neonatal SOD1(G93A) mice, and impact on disease progression and survival was assessed.

RESULTS

This therapy extended median survival by 50% and delayed hindlimb paralysis, with animals remaining ambulatory until the humane endpoint, which was due to rapid body weight loss. AAV9-treated SOD1(G93A) mice showed reduction of mutant human SOD1 mRNA levels in upper and lower motor neurons and significant improvements in multiple parameters including the numbers of spinal motor neurons, diameter of ventral root axons, and extent of neuroinflammation in the SOD1(G93A) spinal cord. Mice also showed previously unexplored changes in pulmonary function, with AAV9-treated SOD1(G93A) mice displaying a phenotype reminiscent of patient pathophysiology.

INTERPRETATION

These studies clearly demonstrate that an AAV9-delivered SOD1-specific artificial microRNA is an effective and translatable therapeutic approach for ALS.

Evolutionary origin of Tbr2-expressing precursor cells and the subventricular zone in the developing cortex

The subventricular zone (SVZ) is greatly expanded in primates with gyrencephalic cortices and is thought to be absent from vertebrates with three-layered, lissencephalic cortices, such as the turtle. Recent work in rodents has shown that Tbr2-expressing neural precursor cells in the SVZ produce excitatory neurons for each cortical layer in the neocortex. Many excitatory neurons are generated through a two-step process in which Pax6-expressing radial glial cells divide in the VZ to produce Tbr2-expressing intermediate progenitor cells, which divide in the SVZ to produce cortical neurons. We investigated the evolutionary origin of SVZ neural precursor cells in the prenatal cerebral cortex by testing for the presence and distribution of Tbr2-expressing cells in the prenatal cortex of reptilian and avian species. We found that mitotic Tbr2(+) cells are present in the prenatal cortex of lizard, turtle, chicken, and dove. Furthermore, Tbr2(+) cells are organized into a distinct SVZ in the dorsal ventricular ridge (DVR) of turtle forebrain and in the cortices of chicken and dove. Our results are consistent with the concept that Tbr2(+) neural precursor cells were present in the common ancestor of mammals and reptiles. Our data also suggest that the organizing principle guiding the assembly of Tbr2(+) cells into an anatomically distinct SVZ, both developmentally and evolutionarily, may be shared across vertebrates. Finally, our results indicate that Tbr2 expression can be used to test for the presence of a distinct SVZ and to define the boundaries of the SVZ in developing cortices.

Lateral ventricle injection of orexin-A ameliorates central precocious puberty in rat via inhibiting the expression of MEG3

BACKGROUND

Central precocious puberty (CPP) is characterized as increasing gonadotropin-releasing hormone (GnRH) release. Orexin-A has also been shown to affect GnRH release. However, there are few reports about the effect of orexin A on the treatment of CPP.

METHODS

After establishing the precocious puberty model, the rats were divided into four groups: normal control, precocious puberty rats, precocious puberty rats treated with normal saline and precocious puberty rats treated with orexin-A. The vaginal opening time, second estrus cycle, ovarian index and uterus index of rats in each group were detected. qRT-PCR was performed to examine the expression of MEG3 and kisspeptin in rats. HT22 cells were transfected with pcDNA-MEG3 to detect the expression of Kisspeptin.

RESULTS

In this study, we found that orexin-A not only delayed the day of vaginal opening and regular estrus cycle days but also decreased the ovarian index and uterus index in rats with CPP. In addition, orexin-A reversed the up-regulation of MEG3 and kisspeptin in rats with CPP. In HT22 cells, the mRNA and protein level of kisspeptin were enhanced by pcDNA-MEG3.

CONCLUSION

Our results suggest that orexin-A ameliorates central precocious puberty in rat and MEG3 might be involved in this effect, suggesting that MEG3 might be a novel target in treating central precocious puberty.

[DIFFERENTIATION AND PROLIFERATION POTENTIAL OF NEURAL STEM CELLS IN SUBVENTRICULAR ZONE OF MICE IN VITRO]

OBJECTIVE

To establish the system of isolation, cultivation, and identification of the neural stem cells (NSCs) from subventricular zone (SVZ) of neonatal mice so as to seek for the appropriate seed cells for potential therapeutic interventions of neurological disorders.

METHODS

NSCs were isolated enzymatically and mechanically from SVZ of neonatal mice and cultured. The cellular morphology was observed by inverted microscopy. Immunocytochemical stainings of anti-Nestin and anti-SOX-2 were used to identify NSCs of passage 3. To study the differentiation of NSCs, NSCs were plated into 24-wells in the medium supplemented without epidermal growth factor (EGF) and basic fibroblastic growth factor (bFGF) for 3 or 7 days. To compare the differentiation and proliferation potential of NSCs with different cultivation time, the BrdU pulse-labeling method and MTT test were used. To identify neurons and astrocytes, the anti-β-tubulin III (Tuj-1) and anti-glial fibrillary acidic protein (GFAP) staining were used.

RESULTS

The cells of the SVZ can be isolated and cultured in vitro, and these cells began to form neurospheres after cultured for 3 days at primary passage. While cultured for 7 days, these cells formed more neurospheres, and the volume of the neurospheres became bigger than neurospheres cultured for 3 days. In addition, after cultured for 7 days, the phenomena of fusion of neurospheres and adherent differentiation of neurospheres were observed under inverted microscope. These cells were provided with the typical phenotype of NSCs. The immunofluorescence staining results revealed that these cells showed positive immunoreactivity to Nestin and SOX-2. During the 4 hours BrdU pulse, the number of proliferated NSCs cultured for 3 days (75.817 ± 2.961) was significantly higher than that of NSCs cultured for 7 days (56.600 ± 4.881) (t = 3.366, P = 0.028). The results of MTT assay revealed that the absorbance (A) value of NSCs cultured for 3 days (0.478 ± 0.025) was significantly higher than that of NSCs which were cultured for 7 days (0.366 ± 0.032)(t = 2.752, P = 0.011). After cultivated without EGF and bFGF, the percentage of Tuj-1 and GFAP positive cells in NSCs was 23.1% ± 3.7% and 23.7% ± 3.8% for 3 days and was 40.1% ± 3.6% and 37.1% ± 4.5% for 7 days, respectively, all showing significant differences (t = 3.285, P = 0.030; t = 3.930, P = 0.017).

CONCLUSION

The NSCs from SVZ of neonatal mice have potentials of self-renewal and multipotential differentiation in vitro. With different cultivation time, the potentials of proliferation and differentiation of NSCs are different.

[Transplantation of human embryonic neural stem cells protects rats against cerebral ischemic injury]

The purpose of this study is to explore the fate and effect of human embryonic neural stem cells (hNSCs) after transplantation into ipsilateral lateral ventricle of stroke rats. Adult rats were exposed to one-hour transient middle cerebral artery occlusion (MCAO), and then hNSCs were transplanted into ipsilateral lateral ventricle 7 days after reperfusion. Infarct volume was calculated by cresyl violet staining. The improvements of neural functions were assessed by behavioral tests. Immunofluorescence staining was performed to observe the migration and differentiation of transplanted hNSCs. The results showed that transplanted hNSCs significantly reduced ischemia-induced infarction in MCAO rats, and improved neural functional restoration when assessed by rotarod, footfault and corner-turn tests. The grafted cells migrated predominantly to several specific brain regions, such as corpus callosum and peri-infarct area. Furthermore, these cells differentiated into oligodendrocytes and astrocytes in corpus callosum, and neurons in peri-infarct parenchyma. These results suggest that transplanted hNSCs through lateral ventricle of the ischemic side may exert effective therapeutic effects on stroke rats via migration and differentiation in specific brain regions.

[Liponeurocytoma in the left lateral ventricle. Presentation of the first case reported in Spain and literature review]

Supratentorial liponeurocytoma is a rare tumor, predominantly appearing in young males. It most commonly affects the lateral ventricles, with involvement of the third ventricle being exceptional. It is defined as a low-grade neuroglial tumor, with areas of associated lipomatosis. The most common clinical manifestation is that resulting from the presence of secondary intracranial hypertension and hydrocephalus. We present the first case reported in Spain of this tumor type and one of the few appearing in the literature so far. We report the case of a 33-year-old male patient, suffering from crural sensitive symptoms and recent onset headache. The radiographic study revealed the presence of a large supratentorial tumor; intraventricular, multicystic, heterogeneous and with areas of associated lipomatosis. The patient underwent surgery and complete tumor resection was achieved. The definitive diagnosis was of supratentorial liponeurocytoma. The presence of a supratentorial intraventricular tumor with areas of fatty degeneration should lead us to consider this type of tumor in the differential diagnosis. Complete tumor resection is considered to be the treatment of choice.

[Cis-diamminedichloroplatinum penetration into the cerebrospinal fluid of the lateral ventricle, postoperative cavity, and lumbar subarachnoid space with or without pre-intravenous mannitol administration in patients with brain metastasis from lung cancer]

We have previously reported that repeated intravenous administration of cis-diamminedichloroplatinum(CDDP)prevented local recurrence of metastatic brain tumors after surgical total excision; however, data on CDDP distribution in the postoperative cavity after intravenous CDDP administration are not available. In the present study, we evaluated the penetration of total platinum(Pt)into the cerebrospinal fluid(CSF)and the effect of intravenous administration of 20%mannitolon total Pt distribution in the plasma and CSF. Total Pt levels in the plasma and CSF were determined immediately after intravenous infusion of CDDP(80mg/m2)for 1 hour, with or without pre-intravenous infusion of 20% mannitol(200mL), in 11 patients with brain metastasis from lung cancer. CSF samples were obtained via Ommaya reservoirs placed in the anterior horn of the lateral ventricle(CSF-V)and the postoperative cavity(CSF-C). Spinal CSF (CSF-L)was also obtained in the last 4 patients of the series via spinal drainage. CDDP was administered intravenously without mannitol 10 days after brain tumor excision, and 1 week after the initial administration of CDDP, CDDP was intravenously administered again after intravenous mannitol administration. CDDP was always administered intravenously at 1:00 PM to rule out the influence of circadian variation. Plasma and CSF were sequentially sampled after intravenous CDDP administration, and their Pt levels were analyzed for Pt content by using atomic absorption spectroscopy. The area under the concentration time curve(AUC)was calculated for plasma and CSF using the moment method. The AUC for total Pt in plasma showed a significantly higher level with the administration of mannitol than without the administration of mannitol(p<0.01, paired t-test). Total Pt levels(AUCs and peak concentrations)in CSF-C were much higher than were those in CSF-V and CSF-L both with and without the administration of mannitol. The ratio(%)of CDDP penetration into CSF(CSF AUC/plasma AUC)was much higher for CSF-C than for CSF-V(p<0.0001)both with and without mannitol administration. However, the CSF penetration ratio with mannitol administration did not differ significantly from that without mannitol administration. Thus, the administration of mannitol did not significantly increase the penetration ratio of total Pt. Creatinine clearance was moderately reduced in all patients during the first administration of CDDP. However, 7 of the 11 patients showed an increase in creatinine clearance after the second administration of CDDP with mannitol.