Mechanisms of hydrocephalus after neonatal and adult intraventricular hemorrhage

Response of Astrocytes to Blood Exposure due to Shunt Insertion in vitro

The breakdown of the ventricular zone (VZ) with the presence of blood in cerebrospinal fluid (CSF) has been shown to increase shunt catheter obstruction in the treatment of hydrocephalus, but the mechanisms by which this occurs are generally unknown. Using a custom-built incubation chamber, we immunofluorescently assayed cell attachment and morphology on shunt catheters with and without blood after 14 days. Samples exposed to blood showed significantly increased cell attachment (average total cell count 392.0±317.1 versus control of 94.7±44.5, P<0.0001). Analysis of the glial fibrillary acidic protein (GFAP) expression showed similar trends (854.4±450.7 versus control of 174.3±116.5, P<0.0001). An in vitro model was developed to represent the exposure of astrocytes to blood following an increase in BBB permeability. Exposure of astrocytes to blood increases the number of cells and their spread on the shunt.

Inflammatory hydrocephalus

Reparative inflammation is an important protective response that eliminates foreign organisms, damaged cells, and physical irritants. However, inappropriately triggered or sustained inflammation can respectively initiate, propagate, or prolong disease. Post-hemorrhagic (PHH) and post-infectious hydrocephalus (PIH) are the most common forms of hydrocephalus worldwide. They are treated using neurosurgical cerebrospinal fluid (CSF) diversion techniques with high complication and failure rates. Despite their distinct etiologies, clinical studies in human patients have shown PHH and PIH share similar CSF cytokine and immune cell profiles. Here, in light of recent work in model systems, we discuss the concept of "inflammatory hydrocephalus" to emphasize potential shared mechanisms and potential therapeutic vulnerabilities of these disorders. We propose that this change of emphasis could shift our thinking of PHH and PIH from a framework of life-long neurosurgical disorders to that of preventable conditions amenable to immunomodulation.

Bilateral hyperplasia of choroid plexus with severe CSF production: a case report and review of the glymphatic system

BACKGROUND

An important feature of hydrocephalus is the alteration of the cerebral spinal fluid (CSF) homeostasis. New insights in the understanding of production, secretion, and absorption of CSF, along with the discovery of the glymphatic system (GS), can be useful for a better understanding and treatment of hydrocephalus in disorders with CSF overproduction.

CASE DESCRIPTION

A 1-year-old patient was diagnosed with communicating hydrocephalus; ventricle peritoneal shunt (VPS) is installed and ascites developed. VPS is exposed, yielding volumes of 1000-1200ml/day CSF per day. MRI is performed showing generalized choroidal plexus hyperplasia. Bilateral endoscopic coagulation of thechoroid plexus was performed in 2 stages (CPC) however the high rate of CSF production persisted, needing a bilateral plexectomy through septostomy, which finally decreased the CSF outflow.

DISCUSSION

New knowledge about the CSF physiology will help to propose better treatment depending on the cause of the hydrocephalus. The GS is becoming an additional reason to better study and develop new therapies focused of the modulation of alternative CSF reabsorption.

CONCLUSION

Despite the current knowledge about hydrocephalus, we remain without a complete understanding of the pathophysiology of this condition. GS could be more important than conventional concept of reabsorption of CSF in the arachnoid villi, therefore GS could be a new key point, which will guide future investigations.

External ventricular drainage for posthemorrhagic ventricular dilatation in preterm infants: insights on efficacy and failure

OBJECTIVE

The objective of this study was to describe the clinical and neuroradiological characteristics of a cohort of preterm infants who had undergone external ventricular drain insertion as a temporary measure to treat posthemorrhagic ventricular dilatation. In addition, the authors investigated the factors predicting permanent shunt dependency.

METHODS

The authors retrospectively reviewed the medical records of a cohort of preterm infants who had undergone external ventricular drain insertion at Gaslini Children's Hospital (Genoa, Italy) between March 2012 and February 2018. They also analyzed clinical characteristics and magnetic resonance imaging data, including diffusion- and susceptibility-weighted imaging studies, which were obtained before both catheter insertion and removal.

RESULTS

Twenty-eight infants were included in the study. The mean gestational age was 28.2 ± 2.7 weeks, and the mean birth weight was 1209 ± 476 g. A permanent ventriculoperitoneal shunt was inserted in 15/28 (53.6%) infants because of the failure of external ventricular drainage as a temporary treatment option. Compared with the shunt-free group, the shunt-dependent group had a significantly lower gestational age (29.3 ± 2.3 vs 27.2 ± 2.7 weeks, p = 0.035) and tended toward a lower birth weight (p = 0.056). None of the clinical and neuroradiological characteristics significantly differed between the shunt-free and shunt-dependent groups at the time of catheter insertion. As expected, ventricular parameters as well as the intraventricular extension of intracerebral hemorrhage, as assessed using the intraventricular hemorrhage score, were reportedly higher in the shunt-dependent group than in the shunt-free group before catheter removal.

CONCLUSIONS

External ventricular drainage is a reliable first-line treatment for posthemorrhagic hydrocephalus. However, predicting its efficacy as a unique treatment remains challenging. A lower gestational age is associated with a higher risk of posthemorrhagic hydrocephalus progression, suggesting that the more undeveloped the mechanisms for the clearance of blood degradation products, the greater the risk of requiring permanent cerebrospinal fluid diversion, although sophisticated MRI investigations are currently unable to corroborate this hypothesis.

Cumulative Damage: Cell Death in Posthemorrhagic Hydrocephalus of Prematurity

Globally, approximately 11% of all infants are born preterm, prior to 37 weeks’ gestation. In these high-risk neonates, encephalopathy of prematurity (EoP) is a major cause of both morbidity and mortality, especially for neonates who are born very preterm (<32 weeks gestation). EoP encompasses numerous types of preterm birth-related brain abnormalities and injuries, and can culminate in a diverse array of neurodevelopmental impairments. Of note, posthemorrhagic hydrocephalus of prematurity (PHHP) can be conceptualized as a severe manifestation of EoP. PHHP impacts the immature neonatal brain at a crucial timepoint during neurodevelopment, and can result in permanent, detrimental consequences to not only cerebrospinal fluid (CSF) dynamics, but also to white and gray matter development. In this review, the relevant literature related to the diverse mechanisms of cell death in the setting of PHHP will be thoroughly discussed. Loss of the epithelial cells of the choroid plexus, ependymal cells and their motile cilia, and cellular structures within the glymphatic system are of particular interest. Greater insights into the injuries, initiating targets, and downstream signaling pathways involved in excess cell death shed light on promising areas for therapeutic intervention. This will bolster current efforts to prevent, mitigate, and reverse the consequential brain remodeling that occurs as a result of hydrocephalus and other components of EoP.

Neuroprotection offered by mesenchymal stem cells in perinatal brain injury: Role of mitochondria, inflammation, and reactive oxygen species

Preclinical studies have shown that mesenchymal stem cells have a positive effect in perinatal brain injury models. The mechanisms that cause these neurotherapeutic effects are not entirely intelligible. Mitochondrial damage, inflammation, and reactive oxygen species are considered to be critically involved in the development of injury. Mesenchymal stem cells have immunomodulatory action and exert mitoprotective effects which attenuate production of reactive oxygen species and promote restoration of tissue function and metabolism after perinatal insults. This review summarizes the present state, the underlying causes, challenges and possibilities for effective clinical translation of mesenchymal stem cell therapy.

Novel therapeutics for hydrocephalus: Insights from animal models

Hydrocephalus is a cerebrospinal fluid physiological disorder that causes ventricular dilation with normal or high intracranial pressure. The current regular treatment for hydrocephalus is cerebrospinal fluid shunting, which is frequently related to failure and complications. Meanwhile, considering that the current nonsurgical treatments of hydrocephalus can only relieve the symptoms but cannot eliminate this complication caused by primary brain injuries, the exploration of more effective therapies has become the focus for many researchers. In this article, the current research status and progress of nonsurgical treatment in animal models of hydrocephalus are reviewed to provide new orientations for animal research and clinical practice.

The Pathogenesis of Hydrocephalus Following Aneurysmal Subarachnoid Hemorrhage

Hydrocephalus is a common complication of aneurysmal subarachnoid hemorrhage (aSAH) and reportedly contributes to poor neurological outcomes. In this review, we summarize the molecular and cellular mechanisms involved in the pathogenesis of hydrocephalus following aSAH and summarize its treatment strategies. Various mechanisms have been implicated for the development of chronic hydrocephalus following aSAH, including alterations in cerebral spinal fluid (CSF) dynamics, obstruction of the arachnoid granulations by blood products, and adhesions within the ventricular system. Regarding molecular mechanisms that cause chronic hydrocephalus following aSAH, we carried out an extensive review of animal studies and clinical trials about the transforming growth factor-β/SMAD signaling pathway, upregulation of tenascin-C, inflammation-dependent hypersecretion of CSF, systemic inflammatory response syndrome, and immune dysregulation. To identify the ideal treatment strategy, we discuss the predictive factors of shunt-dependent hydrocephalus between surgical clipping and endovascular coiling groups. The efficacy and safety of other surgical interventions including the endoscopic removal of an intraventricular hemorrhage, placement of an external ventricular drain, the use of intraventricular or cisternal fibrinolysis, and an endoscopic third ventriculostomy on shunt dependency following aSAH were also assessed. However, the optimal treatment is still controversial, and it necessitates further investigations. A better understanding of the pathogenesis of acute and chronic hydrocephalus following aSAH would facilitate the development of treatments and improve the outcome.

Stem cell restores thalamocortical plasticity to rescue cognitive deficit in neonatal intraventricular hemorrhage

Severe neonatal intraventricular hemorrhage (IVH) patients incur long-term neurologic deficits such as cognitive disabilities. Recently, the intraventricular transplantation of allogeneic human umbilical cord blood-derived mesenchymal stem cells (MSCs) has drawn attention as a therapeutic potential to treat severe IVH. However, its pathological synaptic mechanism is still elusive. We here demonstrated that the integration of the somatosensory input was significantly distorted by suppressing feed-forward inhibition (FFI) at the thalamocortical (TC) inputs in the barrel cortices of neonatal rats with IVH by using BOLD-fMRI signal and brain slice patch-clamp technique. This is induced by the suppression of Hebbian plasticity via an increase in tumor necrosis factor-α expression during the critical period, which can be effectively reversed by the transplantation of MSCs. Furthermore, we showed that MSC transplantation successfully rescued IVH-induced learning deficits in the sensory-guided decision-making in correlation with TC FFI in the layer 4 barrel cortex.

CD47 blocking antibody accelerates hematoma clearance and alleviates hydrocephalus after experimental intraventricular hemorrhage

Background CD47, a glycoprotein on red blood cell membranes, inhibits phagocytosis via interaction with signal regulatory protein α on phagocytes. Our previous research has demonstrated that blocking CD47 accelerates hematoma clearance and reduces brain injury after intracerebral hemorrhage. The current study investigated whether phagocytosis or erythrocyte CD47 impacts hematoma resolution and hydrocephalus development after intraventricular hemorrhage (IVH). Methods Adult (3-month-old) male Fischer 344 rats were intraventricularly injected with 200 μl autologous blood, mixed with either CD47 blocking antibody or isotype IgG, or 200 μl saline as control. In subgroups of CD47 blocking antibody treated rats, clodronate liposomes (to deplete microglia/monocyte-derived macrophages) or control liposomes were co-injected. Magnetic resonance imaging (MRI) was used to evaluate ventricular volume and intraventricular T2* lesion volume (estimating hematoma volume). The brains were harvested after 4 or 72 h for histology to evaluate phagocytosis. Results In adult male rats, CD47 blocking antibody alleviated hydrocephalus development by day 3. In addition, the CD47 blocking antibody reduced intraventricular T2* lesion and T2* non-hypointense lesion size after IVH through day 1 to day 3. Erythrophagocytosis was observed as soon as 4 h after IVH and was enhanced on day 3. Furthermore, intra-hematoma infiltration of CD68, heme oxygenase-1 and ferritin positive phagocytes were upregulated by CD47 blockade by day 3. Clodronate liposomes co-injection caused more severe hydrocephalus and weight loss. Conclusion Blocking CD47 in the hematoma accelerated hematoma clearance and alleviated hemolysis and hydrocephalus development after IVH, suggesting CD47 might be valuable in the future treatment for IVH.

Hemoglobin induces oxidative stress and mitochondrial dysfunction in oligodendrocyte progenitor cells

Oligodendrocyte progenitor cells (OPCs) in the infant brain give rise to mature oligodendrocytes that myelinate CNS axons. OPCs are particularly vulnerable to oxidative stress that occurs in many forms of brain injury. One common cause of infant brain injury is neonatal intraventricular hemorrhage (IVH), which releases blood into the CSF and brain parenchyma of preterm infants. Although blood contains the powerful oxidant hemoglobin, the direct effects of hemoglobin on OPCs have not been studied. We utilized a cell culture system to test if hemoglobin induced free radical production and mitochondrial dysfunction in OPCs. We also tested if phenelzine (PLZ), an FDA-approved antioxidant drug, could protect OPCs from hemoglobin-induced oxidative stress. OPCs were isolated from Sprague Dawley rat pups and exposed to hemoglobin with and without PLZ. Outcomes assessed included intracellular reactive oxygen species levels using 2',7'-dichlorodihydrofluorescein diacetate (DCF-DA) fluorescent dye, oxygen consumption using the XFe96 Seahorse assay, and proliferation measured by BrdU incorporation assay. Hemoglobin induced oxidative stress and impaired mitochondrial function in OPCs. PLZ treatment reduced hemoglobin-induced oxidative stress and improved OPC mitochondrial bioenergetics. The effects of hemoglobin and PLZ on OPC proliferation were not statistically significant, but showed trends towards hemoglobin reducing OPC proliferation and PLZ increasing OPC proliferation (P=0.06 for both effects). Collectively, our results indicate that hemoglobin induces mitochondrial dysfunction in OPCs and that antioxidant therapy reduces these effects. Therefore, antioxidant therapy may hold promise for white matter diseases in which hemoglobin plays a role, such as neonatal IVH.

Blood-brain barrier disruption and ventricular enlargement are the earliest neuropathological changes in rats with repeated sub-concussive impacts over 2 weeks

Repeated sub-concussive impact (e.g. soccer ball heading), a significantly lighter form of mild traumatic brain injury, is increasingly suggested to cumulatively alter brain structure and compromise neurobehavioural function in the long-term. However, the underlying mechanisms whereby repeated long-term sub-concussion induces cerebral structural and neurobehavioural changes are currently unknown. Here, we utilised an established rat model to investigate the effects of repeated sub-concussion on size of lateral ventricles, cerebrovascular blood-brain barrier (BBB) integrity, neuroinflammation, oxidative stress, and biochemical distribution. Following repeated sub-concussion 3 days per week for 2 weeks, the rats showed significantly enlarged lateral ventricles compared with the rats receiving sham-only procedure. The sub-concussive rats also presented significant BBB dysfunction in the cerebral cortex and hippocampal formation, whilst neuromotor function assessed by beamwalk and rotarod tests were comparable to the sham rats. Immunofluorescent and spectroscopic microscopy analyses revealed no significant changes in neuroinflammation, oxidative stress, lipid distribution or protein aggregation, within the hippocampus and cortex. These data collectively indicate that repeated sub-concussion for 2 weeks induce significant ventriculomegaly and BBB disruption, preceding neuromotor deficits.

Germinal Matrix-Intraventricular Hemorrhage: A Tale of Preterm Infants

Germinal matrix-intraventricular hemorrhage (GM-IVH) is a common intracranial complication in preterm infants, especially those born before 32 weeks of gestation and very-low-birth-weight infants. Hemorrhage originates in the fragile capillary network of the subependymal germinal matrix of the developing brain and may disrupt the ependymal lining and progress into the lateral cerebral ventricle. GM-IVH is associated with increased mortality and abnormal neurodevelopmental outcomes such as posthemorrhagic hydrocephalus, cerebral palsy, epilepsy, severe cognitive impairment, and visual and hearing impairment. Most affected neonates are asymptomatic, and thus, diagnosis is usually made using real-time transfontanellar ultrasound. The present review provides a synopsis of the pathogenesis, grading, incidence, risk factors, and diagnosis of GM-IVH in preterm neonates. We explore brief literature related to outcomes, management interventions, and pharmacological and nonpharmacological prevention strategies for GM-IVH and posthemorrhagic hydrocephalus.

Risk factors and short-term complications of high-grade intraventricular hemorrhages in preterm neonates in training hospitals of Alborz

Objectives

The aim of this study is to determine risk factors and short-term complications of high-grade intraventricular hemorrhages (IVHs) in preterm neonates. Other topics of investigation include the increase in complications of IVH with its severity and the effect of IVH risk factors on the severity of IVH.

Materials & Methods

We conducted a retrospective case-control study of 436 consecutive preterm neonates with high-grade (3, 4) IVHs admitted in training hospitals of Alborz University in Karaj, Iran, from 2012 to 2017. The risk factors and short-term complications were assessed and analyzed in the subjects by SPSS 19.

Results

Out of 10 000 eligible neonates, we identified 1203 premature infants with IVH. A total of 436 infants with IVH grades 3 and 4 were allocated to the case group. The control group consisted of 767 infants with IVH grades 1 and 2. This study revealed that the most common risk factors of IVH include lack of corticosteroid use in 67.2%, low Apgar score in 10%, and surfactant use in 5.7% of the patients. Ten percent (31 cases) had short-term complications (18 hydrocephalus and 13 death cases). Male gender (P = .006) and lower gestational age (P = .0001) contributed to higher grades of IVH.

Conclusion

According to the results obtained in this study, it may be concluded that the lack of corticosteroid use is the most common risk factor for IVH, and short-term complications may be seen in one-tenth of the cases.

Inflammatory Markers in Cerebrospinal Fluid from Patients with Hydrocephalus: A Systematic Literature Review

OBJECTIVE

The aim of this systematic review was to evaluate existing literature on inflammatory markers in CSF from patients with hydrocephalus and identify potential markers capable of promoting hydrocephalus development and progression.

METHODS

Relevant studies published before December 3rd 2020 were identified from PubMed, Embase, and reference lists. Studies were screened for eligibility using the predefined inclusion and exclusion criteria. Data from eligible studies were extracted, and sources of bias were evaluated. We included articles written in English investigating inflammatory markers in CSF from patients with hydrocephalus and control subjects. The review was conducted according to the PRISMA guidelines by three independent reviewers.

RESULTS

Twenty-two studies analyzed CSF from 311 patients with idiopathic normal pressure hydrocephalus (iNPH), 178 with posthemorrhagic hydrocephalus (PHH), 151 with other hydrocephalus diagnoses, and 394 control subjects. Fifty-eight inflammatory markers were investigated. The CSF of iNPH patients had increased CSF levels of IL-6, IL-1β, and LRG compared with control subjects, whereas the CSF of PHH patients had increased levels of IL-6, IL-18, and VEGF. CSF from patients with "other hydrocephalus diagnoses" had elevated IFN-γ compared to control subjects, and VEGF was increased in congenital hydrocephalus, spina bifida, and hydrocephalus associated with tuberculous meningitis compared with controls.

CONCLUSION

IL-6, IL-1β, LRG, IL-18, VEGF, and IFN-γ are elevated in CSF from patients with hydrocephalus and may be involved in promotion of hydrocephalus development and progression. They may serve as novel disease biomarkers, and their signaling pathways may represent targets for pharmacological management of hydrocephalus.

Thrombocytopenia: is it a prognostic factor for development of post-hemorrhagic hydrocephalus in neonates?

PURPOSE

Post-hemorrhagic hydrocephalus (PHH) is a rare but serious complication among premature babies in the neonatal intensive care unit. The causes of PHH are still not entirely understood, and its prevention and treatment are controversial. We tried to analyze the risk factors for such complication in our cohort.

METHODS

We reviewed our neonatology data bank and included all preterms below 28 weeks who were born in the period between 1999 and 2014 and suffered from an intraventricular hemorrhage (IVH). We reviewed gestational age, gender, birth weight, type of birth, IVH degree, comorbidities, therapy, complications, time to event, protein content of cerebrospinal fluid, and clinical follow-up.

RESULTS

We identified 180 patients, divided into two subgroups, "B1" with 37 cases (IVH + PHH) and "B2" with 143 cases (IVH - PHH). In group B1, the presence of IVH grades I, II, III, or IV was in 11%, 19%, and 70% respectively. Nineteen patients were treated with a ventricular access device (VAD) or external ventricular drain (EVD). A total of 20 shunts were implanted, with 11 revisions (55%). One patient suffered from thrombocytopenia. In subgroup B2, 51% showed IVH grade I, whereas severe IVH grades were only present in 22%. 25.9% suffered from thrombocytopenia. Thrombocytopenia was significantly higher in patients who did not develop PHH (p value: 0.002).

CONCLUSION

According to our results, thrombocytopenia could play a decisive role in avoiding development of PHH as a sequel of IVH. We recommend a randomized controlled trial to assess the possible efficacy of antiplatelet drugs in avoiding PHH in this vulnerable group.

Factors Impacting Hydrocephalus Incidence in Intracerebral Hemorrhage: A Retrospective Analysis

OBJECTIVE

To test which intracerebral hemorrhage (ICH) characteristics impact incidence of hydrocephalus and characterize subsequent impact on outcomes.

METHODS

A search of the electronic medical record of Sinai Grace Hospital between January 2009 and April 2018 using International Classification of Diseases, Ninth Revision and Tenth Revision codes for ICH identified 847 patients. After excluding patients with hemorrhagic conversion of stroke, subarachnoid hemorrhage, and traumatic hemorrhage, 560 patients remained for analysis. Generalized linear modeling was used to assess variance in modified Rankin Scale (mRS) score and length of stay.

RESULTS

Incidence of hydrocephalus on arrival varied with ICH volume (P < 0.001), intraventricular hemorrhage (IVH) status (P < 0.001), bleed location (P < 0.001), and external ventricular drain (EVD) status (P < 0.001). An EVD was inserted in 47% of patients presenting with IVH (n = 102/217), while 4% of patients without IVH received an EVD (n = 14/343) (P < 0.001). Hemorrhage locations had different rates of EVD placement: thalamic 43%, basal ganglia 22%, cerebellar 28%, brainstem 21%, lobar 7% (P < 0.001). Shunt dependency did not vary between bleed locations (P = 0.072). Variance in mRS score was explained by IVH, bleed location, hydrocephalus on arrival, and ICH volumes. In particular, cerebellar hemorrhage location was associated with better outcomes (mean discharge mRS score of 3.3 vs. 3.9, P < 0.001).

CONCLUSIONS

Bleed characteristics affect incidence of hydrocephalus on admission, rates of long-term shunt dependency, and outcomes. Hemorrhage location did not predict shunt dependency; however, it did predict outcomes. Specifically, cerebellar ICH was associated with a better discharge mRS score.

Early intervention and neurodevelopmental outcome of infants with posthemorrhagic hydrocephalus: A case series and literature review

OBJECTIVE

Intraventricular hemorrhage (IVH) is the most common central nervous system pathology in preterm infants. No consensus has been reached over the best indication for intervention in patients with posthemorrhagic hydrocephalus (PHH). The authors present the neurological outcome of infants with IVH and an early treatment approach, defined as an intervention when ventricular dilation is less than 4-mm over the 97th-percentile of Levene's index.

METHODS

We performed a retrospective case-series study of 12 infants who had IVH and an early intervention, their neurological development was evaluated after 18-months of corrected age using the Bayley-III Scales. Measures of central tendency and Pearson's correlation were used for data analysis.

RESULTS

In a 15-month period, twelve patients were diagnosed with IVH and underwent an early intervention. At the time of diagnosis, 2 patients had grade II IVH, 7 grade III, and 3 grade IV. Subgaleal shunt was the first intervention. 9 (75 %) ultimately required a ventriculoperitoneal shunt. A total of 9 (75 %) patients had normal cognitive scores, 7 (58.3 %) for the language-composite, and 8 (66.7 %) for the motor-composite. 6 (50 %) patients had normal scores in all composites. The average scores reported normal results (CC:98.33 ± 22.59; LC:98.25 ± 23.93; MC:88.58 ± 21.47). There was a significant correlation between antenatal steroids and the LC-score (p = 0.044).

CONCLUSIONS

Half of the patients with PHH and early neurosurgical interventions had an average or above average neurodevelopmental score in all three areas. Current literature and undergoing clinical trials have shown promising results on the implementation of this type of intervention.

Acute brain inflammation, white matter oxidative stress, and myelin deficiency in a model of neonatal intraventricular hemorrhage

OBJECTIVE

Neonatal intraventricular hemorrhage (IVH) leads to posthemorrhagic hydrocephalus (PHH), brain injury, and long-term disability. Current therapy for IVH is based on treating PHH but does not address the underlying brain injury. In order to develop pharmacological treatment for IVH, there must be a better understanding of the underlying pathology of this disease. This study was designed to determine the time course of the acute inflammation and oxidative stress that may underlie the progressive pathology of IVH. The authors sought to understand the temporal relationships among inflammation, oxidative stress, and white matter pathology in a rat model of IVH.

METHODS

A rat model of IVH consisting of hemoglobin injection into the lateral ventricle was used. Tissue was analyzed via biochemical and histological methods to map the spatiotemporal distribution of innate immune activation and oxidative stress. White matter was quantified using both immunohistochemistry and Western blot for myelin basic protein (MBP) in the corpus callosum.

RESULTS

IVH led to acute induction of inflammatory cytokines, followed by oxidative stress. Oxidative stress was concentrated in white matter, adjacent to the lateral ventricles. Animals with IVH initially gained weight at a lower rate than control animals and had larger ventricles and less MBP than control animals.

CONCLUSIONS

Experimental IVH induces global inflammation throughout the brain and oxidative stress concentrated in the white matter. Both of these phenomena occur early after IVH. This has implications for human neonates with immature white matter that is exquisitely sensitive to inflammation and oxidative stress. Antiinflammatory or antioxidant therapy for IVH may need to be initiated early in order to protect developing white matter.

The Role of Thrombin in Brain Injury After Hemorrhagic and Ischemic Stroke

Thrombin is increased in the brain after hemorrhagic and ischemic stroke primarily due to the prothrombin entry from blood either with a hemorrhage or following blood-brain barrier disruption. Increasing evidence indicates that thrombin and its receptors (protease-activated receptors (PARs)) play a major role in brain pathology following ischemic and hemorrhagic stroke (including intracerebral, intraventricular, and subarachnoid hemorrhage). Thrombin and PARs affect brain injury via multiple mechanisms that can be detrimental or protective. The cleavage of prothrombin into thrombin is the key step of hemostasis and thrombosis which takes place in every stroke and subsequent brain injury. The extravascular effects and direct cellular interactions of thrombin are mediated by PARs (PAR-1, PAR-3, and PAR-4) and their downstream signaling in multiple brain cell types. Such effects include inducing blood-brain-barrier disruption, brain edema, neuroinflammation, and neuronal death, although low thrombin concentrations can promote cell survival. Also, thrombin directly links the coagulation system to the immune system by activating interleukin-1α. Such effects of thrombin can result in both short-term brain injury and long-term functional deficits, making extravascular thrombin an understudied therapeutic target for stroke. This review examines the role of thrombin and PARs in brain injury following hemorrhagic and ischemic stroke and the potential treatment strategies which are complicated by their role in both hemostasis and brain.

Mechanical injury and blood are drivers of spatial memory deficits after rapid intraventricular hemorrhage

Aneurysmal intraventricular hemorrhage (IVH) survivors may recover with significant deficits in learning and memory. The goal of this study was to investigate the mechanism of memory decline after intraventricular aneurysm rupture. We developed an aneurysmal IVH rat model by injecting autologous, arterial blood over the period of two minutes into the right lateral ventricle. We also evaluated the effects of a volume-matched artificial cerebrospinal fluid (CSF) control, thrombin and the mode of delivery (pulsed hand injection versus continuous pump infusion). We performed magnetic resonance brain imaging after 1 and 5 weeks to evaluate for hydrocephalus and histological analysis of the dentate gyrus after 6 weeks. Only animals which underwent a whole blood pulsed hand injection had a spatial memory acquisition and retention deficit 5 weeks later. These animals had larger ventricles at 1 and 5 weeks than animals which underwent a continuous pump infusion of whole blood. We did not find a decline in dentate gyrus granule cell neurons or an impairment in dentate gyrus neurogenesis or differentiation 6 weeks after IVH. Rapid injections of blood or volume resulted in microglial activation in the dentate gyrus. In conclusion, our results point to mechanical injury as the predominant mechanism of memory decline after intraventricular aneurysmal rupture. However, volume-matched pulsed injections of artificial CSF did not create a spatial memory deficit at 5 weeks. Therefore, whole blood itself must play a role in the mechanism. Further research is required to evaluate whether the viscosity of blood causes additional mechanical disruption and hydrocephalus through a primary injury mechanism or whether the toxicity of blood causes a secondary injury mechanism that leads to the observed spatial memory deficit after 5 weeks.

Resolution of neonatal posthemorrhagic ventricular dilation coincident with patent ductus arteriosus ligation: case report

Preterm infants commonly present with a hemodynamically significant patent ductus arteriosus (hsPDA). The authors describe the case of a preterm infant with posthemorrhagic ventricular dilation, which resolved in a temporally coincident fashion to repair of hsPDA. The presence of a PDA with left-to-right shunting was confirmed at birth on echocardiogram and was unresponsive to repeated medical intervention. Initial cranial ultrasound revealed periventricular-intraventricular hemorrhage. Follow-up serial ultrasound showed resolving intraventricular hemorrhage and progressive bilateral hydrocephalus. At 5 weeks, the ductus was ligated with the goal of improving hemodynamic stability prior to CSF diversion. However, neurosurgical intervention was not required due to improvement of ventriculomegaly occurring immediately after PDA ligation. No further ventricular dilation was observed at the 6-month follow-up.Systemic venous flow disruption and abnormal patterns of cerebral blood circulation have been previously associated with hsPDA. Systemic hemodynamic change has been reported to follow hsPDA ligation, although association with ventricular normalization has not. This case suggests that the unstable hemodynamic environment due to left-to-right shunting may also impede CSF outflow and contribute to ventriculomegaly. The authors review the literature surrounding pressure transmission between a PDA and the cerebral vessels and present a mechanism by which PDA may contribute to posthemorrhagic ventricular dilation.

Hydrocephalus in infants: the unique biomechanics and why they matter

OBJECT

Hydrocephalus diagnosed prenatally or in infancy differs substantially from hydrocephalus that develops later in life. The purpose of this review is to explore hydrocephalus that begins before skull closure and full development of the brain. Understanding the unique biomechanics of hydrocephalus beginning very early in life is essential to explain two poorly understood and controversial issues. The first is why is endoscopic third ventriculostomy (ETV) less likely to be successful in premature babies and in infants? The second relates to shunt failure in a subset of older patients treated in infancy leading to life-threatening intracranial pressure without increase in ventricular volume.

METHODS

The review will utilize engineering concepts related to ventricular volume regulation to explain the unique nature of hydrocephalus developing in the fetus and infant. Based on these concepts, their application to the treatment of complex issues of hydrocephalus management, and a review of the literature, it is possible to assess treatment strategies specific to the infant or former infant with hydrocephalus-related issues throughout life.

RESULTS

Based on engineering, all hydrocephalus, except in choroid plexus tumors or hyperplasia, relates to restriction of the flow of cerebrospinal fluid (CSF). Hydrocephalus develops when there is a pressure difference from the ventricles and a space exterior to the brain. When the intracranial volume is fixed due to a mature skull, that difference is between the ventricle and the cortical subarachnoid space. Due to the distensibility of the skull, hydrocephalus in infants may develop due to failure of the terminal absorption of CSF. The discussion of specific surgical treatments based on biomechanical concepts discussed here has not been specifically validated by prospective trials. The rare nature of the issues discussed and the need to follow the patients for decades make this quite difficult. A prospective registry would be helpful in the validation of surgical recommendations.

CONCLUSION

The time of first intervention for treatment of hydrocephalus is an important part of the history. Treatment strategies should be based on the assessment of the roll of trans-mantle pressure differences in deciding treatment strategies. Following skull closure distension of the ventricles at the time of shunt failure requires a pressure differential between the ventricles and the cortical subarachnoid space.

Preterm intraventricular hemorrhage in vitro: modeling the cytopathology of the ventricular zone

BACKGROUND

Severe intraventricular hemorrhage (IVH) is one of the most devastating neurological complications in preterm infants, with the majority suffering long-term neurological morbidity and up to 50% developing post-hemorrhagic hydrocephalus (PHH). Despite the importance of this disease, its cytopathological mechanisms are not well known. An in vitro model of IVH is required to investigate the effects of blood and its components on the developing ventricular zone (VZ) and its stem cell niche. To address this need, we developed a protocol from our accepted in vitro model to mimic the cytopathological conditions of IVH in the preterm infant.

METHODS

Maturing neuroepithelial cells from the VZ were harvested from the entire lateral ventricles of wild type C57BL/6 mice at 1-4 days of age and expanded in proliferation media for 3-5 days. At confluence, cells were re-plated onto 24-well plates in differentiation media to generate ependymal cells (EC). At approximately 3-5 days, which corresponded to the onset of EC differentiation based on the appearance of multiciliated cells, phosphate-buffered saline for controls or syngeneic whole blood for IVH was added to the EC surface. The cells were examined for the expression of EC markers of differentiation and maturation to qualitatively and quantitatively assess the effect of blood exposure on VZ transition from neuroepithelial cells to EC.

DISCUSSION

This protocol will allow investigators to test cytopathological mechanisms contributing to the pathology of IVH with high temporal resolution and query the impact of injury to the maturation of the VZ. This technique recapitulates features of normal maturation of the VZ in vitro, offering the capacity to investigate the developmental features of VZ biogenesis.

Long-term Outcomes and Risk Factors Related to Hydrocephalus After Intracerebral Hemorrhage

Hydrocephalus after intracerebral hemorrhage (ICH) is a common and treatable complication. However, the long-term outcomes and factors for predicting hydrocephalus have seldom been studied. The goal of this study was to determine the long-term outcomes and analyze the risk factors of hydrocephalus after ICH. A consecutive series of 1342 patients with ICH were reviewed from 2010 to 2016 to identify significant risk factors for hydrocephalus. Patients with a first-ever ICH without any prior diagnosis of hydrocephalus after ICH were followed up for survival status and cause of death. Risk factors for hydrocephalus were evaluated by using logistic regression analysis. Out of a total of 1342 ICH patients, 120 patients (8.9%) had hydrocephalus. The risk factors for hydrocephalus (≤ 3 days) were infratentorial hemorrhage (p = 0.000), extension to ventricles (p = 0.000), greater ICH volume (p = 0.09), and hematoma expansion (p = 0.01). Extension to ventricles (p = 0.022) was the only independent risk factor for hydrocephalus (4-13 days), while extension to ventricles (p = 0.028), decompressive craniotomy (p = 0.032), and intracranial infection (p = 0.001) were independent predictors of hydrocephalus (≥ 14 days). Patients were followed up for a median of 5.2 years (IQR 3.3-7.3 years). Estimated all-cause mortality was significantly higher in the ICH patients with hydrocephalus than that without hydrocephalus (HR 3.22, 95% CI 2.42-4.28; p = 0.000). Fifty-nine (49.2%) died and 40 (33.3%) had a favorable outcome in patients with hydrocephalus. Of all deaths, 30.5% were from ICH and 64.4% from infection. Hydrocephalus is a frequent complication of ICH and most commonly occurs at the onset of ICH. Patients with hydrocephalus show relatively higher mortality. ClinicalTrials.gov Identifier: NCT02135783 (May 7, 2014).

uPA alleviates kaolin-induced hydrocephalus by promoting the release and activation of hepatocyte growth factor in rats

Urokinase-type plasminogen activator (uPA) was demonstrated to alleviate kaolin-induced communicating hydrocephalus via inhibiting subarachnoid space fibrosis, but the exact mechanism remains elusive. Thus, this study was designed to investigate if hepatocyte growth factor (HGF), which plays a vital role in uPA-triggered inhibiting of fibrosis in multiple systems, is involved in this process in hydrocephalus. There were 2 parts in this study. First, hydrocephalus was induced in rats by basal cistern injection of kaolin. Then rats were treated with saline or uPA and brain tissue and CSF were collected for Western blot and enzyme-linked immuno sorbent assay (ELISA) four days later. Second, kaolin-induced hydrocephalus rats were treated with saline, uPA, uPA + PHA665752 (antagonist of HGF) or PHA665752. Some animals received MRI four weeks later and brains were used for immunofluorescence. The others were euthanized four days later for ELISA. Both levels of total and activated HGF in the CSF was increased after uPA injections, but related mRNA expression of HGF showed no statistical significance when compared with the control group. Further, the effects of uPA that alleviating ventricular enlargement, subarachnoid fibrosis and reactive astrocytosis were partially reversed by PHA665752. Moreover, PHA665752 partially abolished uPA-induced reduction of transforming growth factor- β1(TGF- β1) level in CSF. Our data suggest that uPA effectively inhibited subarachnoid fibrosis and restricted the development of communicating hydrocephalus in rats in part by promoting HGF release and activation, which may further regulate the TGF-β1 expression in CSF.

Serelaxin activates eNOS, suppresses inflammation, attenuates developmental delay and improves cognitive functions of neonatal rats after germinal matrix hemorrhage

Germinal matrix hemorrhage (GMH) is a detrimental form of neonatal CNS injury. Following GMH-mediated eNOS inhibition, inflammation arises, contributing to GMH-induced brain injury. We investigated the beneficial effects of Serelaxin, a clinical tested recombinant Relaxin-2 protein, on brain injury after GMH in rats. We investigated whether effects of Serelaxin are mediated by its ability to activate the GMH-suppressed eNOS pathway resulting in attenuation of inflammatory marker overproduction. GMH was induced by intraparenchymal injection of bacterial collagenase (0.3U). Seven day old Sprague–Dawley rat pups (P7) were used (n = 63). GMH animals were divided in vehicle or serelaxin treated (3 µg once, 30 µg once, 30 µg multiple, i.p., starting 30 after GMH and then daily). Sham operated animals were used. We monitored the developmental profile working memory and spatial function (T-maze and open field test respectively). At day 28, all rats underwent MRI-scans for assessment of changes in cortical thickness and white matter loss. Effects of Serelaxin on eNOS pathway activation and post-GMH inflammation were evaluated. We demonstrated that Serelaxin dose-dependently attenuated GMH-induced developmental delay, protected brain and improved cognitive functions of rats after GMH. That was associated with the decreased post-GMH inflammation, mediated at least partly by amelioration of GMH-induced eNOS inhibition.

Prx2 (Peroxiredoxin 2) as a Cause of Hydrocephalus After Intraventricular Hemorrhage

Background and Purpose- Our recent study demonstrated that release of Prx2 (peroxiredoxin 2) from red blood cells (RBCs) is involved in the inflammatory response and brain injury after intracerebral hemorrhage. The current study investigated the role of extracellular Prx2 in hydrocephalus development after experimental intraventricular hemorrhage. Methods- There were 4 parts in this study. First, Sprague-Dawley rats received an intraventricular injection of lysed RBC or saline and were euthanized at 1 hour for Prx2 measurements. Second, rats received an intraventricular injection of Prx2, deactivated Prx2, or saline. Third, lysed RBC was coinjected with conoidin A, a Prx2 inhibitor, or vehicle. Fourth, rats received Prx2 injection and were treated with minocycline or saline (i.p.). The effects of Prx2 and the inhibitors were examined using magnetic resonance imaging assessing ventriculomegaly, histology assessing ventricular wall damage, and immunohistochemistry to assess inflammation, particularly at the choroid plexus. Results- Intraventricular injection of lysed RBC resulted in increased brain Prx2 and hydrocephalus. Intraventricular injection of Prx2 alone caused hydrocephalus, ventricular wall damage, activation of choroid plexus epiplexus cells (macrophages), and an accumulation of neutrophils. Conoidin A attenuated lysed RBC-induced injury. Systemic minocycline treatment reduced the epiplexus cell activation and hydrocephalus induced by Prx2. Conclusions- Prx2 contributed to the intraventricular hemorrhage-induced hydrocephalus, probably by inducing inflammatory responses in choroid plexus and ventricular wall damage.

Neonatal hydrocephalus leads to white matter neuroinflammation and injury in the corpus callosum of Ccdc39 hydrocephalic mice

OBJECTIVE

The authors sought to determine if hydrocephalus caused a proinflammatory state within white matter as is seen in many other forms of neonatal brain injury. Common causes of hydrocephalus (such as trauma, infection, and hemorrhage) are inflammatory insults themselves and therefore confound understanding of how hydrocephalus itself affects neuroinflammation. Recently, a novel animal model of hydrocephalus due to a genetic mutation in the Ccdc39 gene has been developed in mice. In this model, ciliary dysfunction leads to early-onset ventriculomegaly, astrogliosis, and reduced myelination. Because this model of hydrocephalus is not caused by an antecedent proinflammatory insult, it was utilized to study the effect of hydrocephalus on inflammation within the white matter of the corpus callosum.

METHODS

A Meso Scale Discovery assay was used to measure levels of proinflammatory cytokines in whole brain from animals with and without hydrocephalus. Immunohistochemistry was used to measure macrophage activation and NG2 expression within the white matter of the corpus callosum in animals with and without hydrocephalus.

RESULTS

In this model of hydrocephalus, levels of cytokines throughout the brain revealed a more robust increase in classic proinflammatory cytokines (interleukin [IL]-1β, CXCL1) than in immunomodulatory cytokines (IL-10). Increased numbers of macrophages were found within the corpus callosum. These macrophages were polarized toward a proinflammatory phenotype as assessed by higher levels of CD86, a marker of proinflammatory macrophages, compared to CD206, a marker for antiinflammatory macrophages. There was extensive structural damage to the corpus callosum of animals with hydrocephalus, and an increase in NG2-positive cells.

CONCLUSIONS

Hydrocephalus without an antecedent proinflammatory insult induces inflammation and tissue injury in white matter. Future studies with this model will be useful to better understand the effects of hydrocephalus on neuroinflammation and progenitor cell development. Antiinflammatory therapy for diseases that cause hydrocephalus may be a powerful strategy to reduce tissue damage.

Inflammation in acquired hydrocephalus: pathogenic mechanisms and therapeutic targets

Hydrocephalus is the most common neurosurgical disorder worldwide and is characterized by enlargement of the cerebrospinal fluid (CSF)-filled brain ventricles resulting from failed CSF homeostasis. Since the 1840s, physicians have observed inflammation in the brain and the CSF spaces in both posthaemorrhagic hydrocephalus (PHH) and postinfectious hydrocephalus (PIH). Reparative inflammation is an important protective response that eliminates foreign organisms, damaged cells and physical irritants; however, inappropriately triggered or sustained inflammation can respectively initiate or propagate disease. Recent data have begun to uncover the molecular mechanisms by which inflammation - driven by Toll-like receptor 4-regulated cytokines, immune cells and signalling pathways - contributes to the pathogenesis of hydrocephalus. We propose that therapeutic approaches that target inflammatory mediators in both PHH and PIH could address the multiple drivers of disease, including choroid plexus CSF hypersecretion, ependymal denudation, and damage and scarring of intraventricular and parenchymal (glia-lymphatic) CSF pathways. Here, we review the evidence for a prominent role of inflammation in the pathogenic mechanism of PHH and PIH and highlight promising targets for therapeutic intervention. Focusing research efforts on inflammation could shift our view of hydrocephalus from that of a lifelong neurosurgical disorder to that of a preventable neuroinflammatory condition.

Endoscopic third ventriculostomy inpatient failure rates compared with shunting in post-hemorrhagic hydrocephalus of prematurity

PURPOSE

Endoscopic third ventriculostomy (ETV) has gained traction as a method for treating post-hemorrhagic hydrocephalus of prematurity (PHHP) in an effort to obviate lifelong shunt dependence in neonates. However, data remains limited regarding inpatient failures.

METHODS

A retrospective analysis of the NIS between 1998 and 2014 was performed. Discharges with age < 1 year and ICD-9-CM codes indicating intraventricular hemorrhage of prematurity (772.1x) and ETV/shunt (02.22 and 02.3x) were included. Patients with ICD-9-CM codes for ventricular drain/reservoir (02.21) were excluded to prevent confounding. Time trend series plots were created. Yearly trends were quantified using logarithmic regression analysis. Kaplan-Meier curves were utilized to analyze time to treatment failure. Time to failure for each treatment was compared using log-rank.

RESULTS

A total of 11,017 discharges were identified. ETV was more likely to be utilized at < 29 weeks gestational age (p = 0.0039) and birth weight < 1000 g (p = 0.0039). Shunts were less likely to fail in older and heavier newborns (OR 0.836 p = 0.00456, OR 0.828 p = 0.0001, respectively). Those initially shunted had lower failure rates compared with ETV (OR 0.44, p < 0.0001) but time to failure was longer with ETV (p = 0.04562). 79.5% of ETVs that failed were shunted after the first failure. Shunts were much less likely to undergo ETV if they failed (OR 0.21, p < 0.0001). Higher grade IVH was predictive of shunt failure but not ETV (OR 2.36, p = 0.0129).

CONCLUSIONS

Although ETV can be effective in PHHP, it has a much higher initial failure rate than shunting and should thus be chosen based on a multifactorial approach.

The Neurovascular Unit: Effects of Brain Insults During the Perinatal Period

The neurovascular unit (NVU) is a relatively recent concept in neuroscience that broadly describes the relationship between brain cells and their blood vessels. The NVU incorporates cellular and extracellular components involved in regulating cerebral blood flow and blood-brain barrier function. The NVU within the adult brain has attracted strong research interest and its structure and function is well described, however, the NVU in the developing brain over the fetal and neonatal period remains much less well known. One area of particular interest in perinatal brain development is the impact of known neuropathological insults on the NVU. The aim of this review is to synthesize existing literature to describe structure and function of the NVU in the developing brain, with a particular emphasis on exploring the effects of perinatal insults. Accordingly, a brief overview of NVU components and function is provided, before discussion of NVU development and how this may be affected by perinatal pathologies. We have focused this discussion around three common perinatal insults: prematurity, acute hypoxia, and chronic hypoxia. A greater understanding of processes affecting the NVU in the perinatal period may enable application of targeted therapies, as well as providing a useful basis for research as it expands further into this area.

Posthemorrhagic hydrocephalus development after germinal matrix hemorrhage: Established mechanisms and proposed pathways

In addition to being the leading cause of morbidity and mortality in premature infants, germinal matrix hemorrhage (GMH) is also the leading cause of acquired infantile hydrocephalus. The pathophysiology of posthemorrhagic hydrocephalus (PHH) development after GMH is complex and vaguely understood, although evidence suggests fibrosis and gliosis in the periventricular and subarachnoid spaces disrupts normal cerebrospinal fluid (CSF) dynamics. Theories explaining general hydrocephalus etiology have substantially evolved from the original bulk flow theory developed by Dr. Dandy over a century ago. Current clinical and experimental evidence supports a new hydrodynamic theory for hydrocephalus development involving redistribution of vascular pulsations and disruption of Starling forces in the brain microcirculation. In this review, we discuss CSF flow dynamics, history and development of theoretical hydrocephalus pathophysiology, and GMH epidemiology and etiology as it relates to PHH development. We highlight known mechanisms and propose new avenues that will further elucidate GMH pathophysiology, specifically related to hydrocephalus.

Routine Cerebrospinal Fluid (CSF) Parameters in Patients With Spinal Muscular Atrophy (SMA) Treated With Nusinersen

Background: Nusinersen is an antisense-oligonucleotide (ASO) approved for treatment of 5q-spinal muscular atrophy (SMA). Since the drug cannot cross the blood-brain barrier (BBB), it must be administered into the cerebrospinal fluid (CSF) space repeatedly by lumbar puncture. However, little is known whether ASOs have an impact on CSF routine parameters that may yield information on CSF flow and/or intrathecal inflammation. The objective of this study was to examine CSF routine parameters in SMA patients treated with nusinersen. Methods: Routine CSF parameters [white cell count, total protein, CSF/serum quotients of albumin (Qalb), lactate, and oligoclonal IgG bands (OCB)] of 60 SMA patients (type 1, 2, and 3, aged 7-60 years) were retrospectively analyzed. Results: White cells ranged from 0 to 4/μL in CSF; a singular case of pleocytosis (8/μL) was observed in a patient in parallel with a systemic infection. Total protein and Qalb showed a mild increase from baseline to the following lumbar punctures (except for total protein in CSF at the fourth injection of nusinersen). Lactate levels revealed a stable course. In one patient, positive OCB in CSF were transiently observed. The slight change in total CSF protein and Qalb may be caused by repeated lumbar puncture and/or intrathecal administration of the drug. Conclusion: Our data suggest that a regular examination of routine CSF parameters in patients in which intrathecal ASOs are administered is important to obtain information on possible side effects and to gain further insights into intrathecal processes.

Blood Exposure Causes Ventricular Zone Disruption and Glial Activation In Vitro

Intraventricular hemorrhage (IVH) is the most common cause of pediatric hydrocephalus in North America but remains poorly understood. Cell junction-mediated ventricular zone (VZ) disruption and astrogliosis are associated with the pathogenesis of congenital, nonhemorrhagic hydrocephalus. Recently, our group demonstrated that VZ disruption is also present in preterm infants with IVH. On the basis of this observation, we hypothesized that blood triggers the loss of VZ cell junction integrity and related cytopathology. In order to test this hypothesis, we developed an in vitro model of IVH by applying syngeneic blood to cultured VZ cells obtained from newborn mice. Following blood treatment, cells were assayed for N-cadherin-dependent adherens junctions, ciliated ependymal cells, and markers of glial activation using immunohistochemistry and immunoblotting. After 24-48 hours of exposure to blood, VZ cell junctions were disrupted as determined by a significant reduction in N-cadherin expression (p < 0.05). This was also associated with significant decrease in multiciliated cells and increase in glial fibrillary acid protein-expressing cells (p < 0.05). These observations suggest that, in vitro, blood triggers VZ cell loss and glial activation in a pattern that mirrors the cytopathology of human IVH and supports the relevance of this in vitro model to define injury mechanisms.

Effects of minocycline on epiplexus macrophage activation, choroid plexus injury and hydrocephalus development in spontaneous hypertensive rats

Hydrocephalus has been reported to occur in spontaneous hypertensive rats (SHRs). The purposes of this study were (1) to use T2 magnetic resonance imaging to examine time of onset, (2) to elucidate potential underlying mechanisms and (3) to determine whether minocycline could prevent hydrocephalus development. Ventriculomegaly was evaluated by T2 imaging in SHRs and Wistar-Kyoto rats from weeks 4 to 7 after birth. Brain histology and transmission electron microscopy were used to assess the periventricular and choroid plexus damage. SHRs were also treated with either vehicle or minocycline. We found that hydrocephalus was observed in SHRs but not in Wistar-Kyoto rats. It occurred at seven weeks of age but was not present at four and five weeks. The hydrocephalus was associated with epiplexus cell (macrophage) activation, choroid plexus cell death and damage to the ventricle wall. Treatment with minocycline from week 5 attenuated hydrocephalus development and pathological changes in choroid plexus and ventricular wall at week 7. The current study found that spontaneous hydrocephalus arises at ∼7 weeks in male SHRs. The early development of hydrocephalus (persistent ventricular dilatation) may result from epiplexus cell activation, choroid plexus cell death and periventricular damage, which can be ameliorated by treatment with minocycline.

Activation of epiplexus macrophages in hydrocephalus caused by subarachnoid hemorrhage and thrombin

Aims

We have found that hydrocephalus development in spontaneously hypertensive rats was associated with activation of epiplexus cells. The current study examined whether epiplexus cell activation occurs in a rat subarachnoid hemorrhage (SAH), whether activation would be greater in a subset of rats that developed hydrocephalus and the potential role of thrombin in epiplexus cell activation.

Methods

There were two parts in this study. First, an endovascular perforation was performed in rats to induce SAH. Second, rats received an intraventricular infusion of either thrombin or saline. Magnetic resonance imaging was used to measure the ventricular volumes. Immunofluorescence and immunohistochemistry were used to study epiplexus cell activation.

Results

Iba‐1, OX‐6, and CD68 were expressed in the epiplexus cells of the choroid plexus in sham‐operated rats. SAH increased Iba‐1 and CD68 immunoreactivity in epiplexus cells in addition to an increase in Iba‐1‐positive cell soma size. Those effects were greater in rats that developed hydrocephalus. Intraventricular thrombin mimicked the effects of SAH on epiplexus cell activation and hydrocephalus.

Conclusion

This study supports the concept that epiplexus cell activation is associated with hydrocephalus development. Epiplexus cell activation may be in response to thrombin production after hemorrhage, and it may be a therapeutic target.

Postoperative intraventricular blood: a new modifiable risk factor for early postoperative symptomatic hydrocephalus in children with posterior fossa tumors

OBJECTIVE

To analyze factors associated with the development of early symptomatic hydrocephalus following posterior fossa tumor (PFT) surgery in children.

METHODS

In this retrospective study, data from 148 children (age < 18 years) who underwent primary resection of their PFTs without preoperative permanent CSF diversion procedures were collected. The incidence of symptomatic hydrocephalus within 30 days of tumor resection was studied and its association with various demographic, tumor-related, and surgery-related risk factors was analyzed.

RESULTS

At presentation, 131 (89%) of the 148 patients had symptomatic hydrocephalus. There were 99 males and 49 females (mean age 8.7 years; range 1 to 17 years). Postoperatively, 14 (9.4%) patients required shunt placement for symptomatic hydrocephalus. The indications for shunt surgery were persistent symptoms of raised intracranial pressure (n = 6, 43%), CSF leak from the wound (n = 7, 50%), and tense pseudomeningocele (n = 1, 7%). On multivariate analysis, age < 6 years (OR 5.9, 95% CI 1.6-22.6, p = 0.009) and the presence of intraventricular blood (IVB) on postoperative CT (OR 6.4, 95% CI 1.7-23.7, p = 0.006) were independent risk factors for developing symptomatic hydrocephalus.

CONCLUSIONS

The incidence of postoperative symptomatic hydrocephalus in our series (9.4%) is lower than that reported in most previous studies. Age < 6 years and the presence of postoperative IVB were independent risk factors for developing symptomatic hydrocephalus. Of these, postoperative IVB is probably the only modifiable risk factor.

Intraventricular hemorrhage and posthemorrhagic hydrocephalus in preterm infants: diagnosis, classification, and treatment options

PURPOSE

Intraventricular hemorrhage is the most important adverse neurologic event for preterm and very low weight birth infants in the neonatal period. This pathology can lead to various delays in motor, language, and cognition development. The aim of this article is to give an overview of the knowledge in diagnosis, classification, and treatment options of this pathology.

METHOD

A systematic review has been made.

RESULTS

The cranial ultrasound can be used to identify the hemorrhage and grade it according to the modified Papile grading system. There is no standardized protocol of intervention as there are controversial results on which of the temporizing neurosurgical procedures is best and about the appropriate parameters to consider a conversion to ventriculoperitoneal shunt. However, it has been established that the most important prognosis factor is the involvement and damage of the white matter.

CONCLUSION

More evidence is required to create a standardized protocol that can ensure the best possible outcome for these patients.

Fetal gunshot brain injury leading to late postnatal hydrocephalus

A male fetus was delivered by emergent caesarean section after a term pregnant mother was caught in crossfire and sustained gunshot injury to her abdomen. Examination of the infant was unremarkable except for a small laceration of the scalp at the anterior fontanelle. Skull radiography showed a dense bullet shaped opacity in the brain. He was managed conservatively and was discharged home on full feeds with normal neurological examination. He developed seizures and progressive hydrocephalus, and underwent a ventriculoperitoneal (VP) shunt placement at 5 weeks of age. At 13 months of age the bullet was removed. To our knowledge this is the first report of fetal brain injury with intact bullet in the brain with survival. This case provides the context for a discussion about factors that contribute to survival and favorable prognosis of infants with fetal penetrating gunshot brain injury.

Impaired hippocampal development and outcomes in very preterm infants with perinatal brain injury

Preterm infants are at high risk for brain injury during the perinatal period. Intraventricular hemorrhage and periventricular leukomalacia, the two most common patterns of brain injury in prematurely-born children, are associated with poor neurodevelopmental outcomes. The hippocampus is known to be critical for learning and memory; however, it remains unknown how these forms of brain injury affect hippocampal growth and how the resulting alterations in hippocampal development relate to childhood outcomes. To investigate these relationships, hippocampal segmentations were performed on term equivalent MRI scans from 55 full-term infants, 85 very preterm infants (born ≤32 weeks gestation) with no to mild brain injury and 73 very preterm infants with brain injury (e.g., grade III/IV intraventricular hemorrhage, post-hemorrhagic hydrocephalus, cystic periventricular leukomalacia). Infants then underwent standardized neurodevelopmental testing using the Bayley Scales of Infant and Toddler Development, 3rd edition at age 2 years, corrected for prematurity. To delineate the effects of brain injury on early hippocampal development, hippocampal volumes were compared across groups and associations between neonatal volumes and neurodevelopmental outcomes at age 2 years were explored. Very preterm infants with brain injury had smaller hippocampal volumes at term equivalent age compared to term and very preterm infants with no to mild injury, with the smallest hippocampi among those with grade III/IV intraventricular hemorrhage and post-hemorrhagic hydrocephalus. Further, larger ventricle size was associated with smaller hippocampal size. Smaller hippocampal volumes were related to worse motor performance at age 2 years across all groups. In addition, smaller hippocampal volumes in infants with brain injury were correlated with impaired cognitive scores at age 2 years, a relationship specific to this group. Consistent with our preclinical findings, these findings demonstrate that perinatal brain injury is associated with hippocampal size in preterm infants, with smaller volumes related to domain-specific neurodevelopmental impairments in this high-risk clinical population.

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Perinatal brain injury is related to smaller hippocampal volumes in preterm infants

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Infants with high-grade intraventricular hemorrhage have smallest hippocampi

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Larger ventricular size is related to smaller hippocampal volumes in hydrocephalus

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Smaller hippocampi are related to worse cognitive outcomes in brain injured infants

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Smaller hippocampal volumes associated with worse motor performance across groups

Recent Advances in Rational Diagnosis and Treatment of Normal Pressure Hydrocephalus: A Critical Appraisal on Novel Diagnostic, Therapy Monitoring and Treatment Modalities

BACKGROUND

Normal pressure hydrocephalus (NPH) is a critical brain disorder in which excess Cerebrospinal Fluid (CSF) is accumulated in the brain's ventricles causing damage or disruption of the brain tissues. Amongst various signs and symptoms, difficulty in walking, slurred speech, impaired decision making and critical thinking, and loss of bladder and bowl control are considered the hallmark features of NPH.

OBJECTIVE

The current review was aimed to present a comprehensive overview and critical appraisal of majorly employed neuroimaging techniques for rational diagnosis and effective monitoring of the effectiveness of the employed therapeutic intervention for NPH. Moreover, a critical overview of recent developments and utilization of pharmacological agents for the treatment of hydrocephalus has also been appraised.

RESULTS

Considering the complications associated with the shunt-based surgical operations, consistent monitoring of shunting via neuroimaging techniques hold greater clinical significance. Despite having extensive applicability of MRI and CT scan, these conventional neuroimaging techniques are associated with misdiagnosis or several health risks to patients. Recent advances in MRI (i.e., Sagittal-MRI, coronal-MRI, Time-SLIP (time-spatial-labeling-inversion-pulse), PC-MRI and diffusion-tensor-imaging (DTI)) have shown promising applicability in the diagnosis of NPH. Having associated with several adverse effects with surgical interventions, non-invasive approaches (pharmacological agents) have earned greater interest of scientists, medical professional, and healthcare providers. Amongst pharmacological agents, diuretics, isosorbide, osmotic agents, carbonic anhydrase inhibitors, glucocorticoids, NSAIDs, digoxin, and gold-198 have been employed for the management of NPH and prevention of secondary sensory/intellectual complications.

CONCLUSION

Employment of rational diagnostic tool and therapeutic modalities avoids misleading diagnosis and sophisticated management of hydrocephalus by efficient reduction of Cerebrospinal Fluid (CSF) production, reduction of fibrotic and inflammatory cascades secondary to meningitis and hemorrhage, and protection of brain from further deterioration.

Ventricular shape evaluation on early ultrasound predicts post-hemorrhagic hydrocephalus

BACKGROUND

To compare the ability of ventricular morphology on cranial ultrasound (CUS) versus standard clinical variables to predict the need for temporizing cerebrospinal fluid drainage in newborns with intraventricular hemorrhage (IVH).

METHOD

This is a retrospective study of newborns (gestational age <29 weeks) diagnosed with IVH. Clinical variables known to increase the risk for post-hemorrhagic hydrocephalus were collected. The first CUS with IVH was identified and a slice in the coronal plane was selected. The frontal horns of the lateral ventricles were manually segmented. Automated quantitative morphological features were extracted from both lateral ventricles. Predictive models of the need of temporizing intervention were compared.

RESULTS

Sixty-two newborns met inclusion criteria. Fifteen out of the 62 had a temporizing intervention. The morphological features had a better accuracy predicting temporizing interventions when compared to clinical variables: 0.94 versus 0.85, respectively; p < 0.01 for both. By considering both morphological and clinical variables, our method predicts the need of temporizing intervention with positive and negative predictive values of 0.83 and 1, respectively, and accuracy of 0.97.

CONCLUSION

Early cranial ultrasound-based quantitative ventricular evaluation in premature newborns can predict the eventual use of a temporizing intervention to treat post-hemorrhagic hydrocephalus. This may be helpful for early monitoring and treatment.

A comprehensive review of therapeutic targets that induce microglia/macrophage-mediated hematoma resolution after germinal matrix hemorrhage

Currently, there is no effective treatment for germinal matrix hemorrhage and intraventricular hemorrhage (GMH-IVH), a common and often fatal stroke subtype in premature infants. Secondary brain injury after GMH-IVH is known to involve blood clots that contribute to inflammation and neurological deficits. Furthermore, the subsequent blood clots disrupt normal cerebrospinal fluid circulation and absorption after GMH-IVH, contributing to posthemorrhagic hydrocephalus (PHH). Clinically, GMH-IVH severity is graded on a I to IV scale: Grade I is confined to the germinal matrix, grade II includes intraventricular hemorrhage, grade III includes intraventricular hemorrhage with extension into dilated ventricles, and grade IV includes intraventricular hemorrhage with extension into dilated ventricles as well as parenchymal hemorrhaging. GMH-IVH hematoma volume is the best prognostic indicator, where patients with higher grades have worsened outcomes. Various preclinical studies have shown that rapid hematoma resolution quickly ameliorates inflammation and improves neurological outcomes. Current experimental evidence identifies alternatively activated microglia as playing a pivotal role in hematoma clearance. In this review, we discuss the pathophysiology of GMH-IVH in the development of PHH, microglia/macrophage's role in the neonatal CNS, and established/potential therapeutic targets that enhance M2 microglia/macrophage phagocytosis of blood clots after GMH-IVH.

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.

Extended Combined Neonatal Treatment With Erythropoietin Plus Melatonin Prevents Posthemorrhagic Hydrocephalus of Prematurity in Rats

Posthemorrhagic hydrocephalus of prematurity (PHHP) remains a global challenge. Early preterm infants (<32 weeks gestation), particularly those exposed to chorioamnionitis (CAM), are prone to intraventricular hemorrhage (IVH) and PHHP. We established an age-appropriate, preclinical model of PHHP with progressive macrocephaly and ventriculomegaly to test whether non-surgical neonatal treatment could modulate PHHP. We combined prenatal CAM and postnatal day 1 (P1, equivalent to 30 weeks human gestation) IVH in rats, and administered systemic erythropoietin (EPO) plus melatonin (MLT), or vehicle, from P2 to P10. CAM-IVH rats developed progressive macrocephaly through P21. Macrocephaly was accompanied by ventriculomegaly at P5 (histology), and P21 (ex vivo MRI). CAM-IVH rats showed impaired performance of cliff aversion, a neonatal neurodevelopmental test. Neonatal EPO+MLT treatment prevented macrocephaly and cliff aversion impairment, and significantly reduced ventriculomegaly. EPO+MLT treatment prevented matted or missing ependymal motile cilia observed in vehicle-treated CAM-IVH rats. EPO+MLT treatment also normalized ependymal yes-associated protein (YAP) mRNA levels, and reduced ependymal GFAP-immunolabeling. Vehicle-treated CAM-IVH rats exhibited loss of microstructural integrity on diffusion tensor imaging, which was normalized in EPO+MLT-treated CAM-IVH rats. In summary, combined prenatal systemic inflammation plus early postnatal IVH caused progressive macrocephaly, ventriculomegaly and delayed development of cliff aversion reminiscent of PHHP. Neonatal systemic EPO+MLT treatment prevented multiple hallmarks of PHHP, consistent with a clinically viable, non-surgical treatment strategy.

Post hemorrhagic hydrocephalus and neurodevelopmental outcomes in a context of neonatal intraventricular hemorrhage: an institutional experience in 122 preterm children

BACKGROUND

Intraventricular hemorrhage (IVH) is a frequent complication in extreme and very preterm births. Despite a high risk of death and impaired neurodevelopment, the precise prognosis of infants with IVH remains unclear. The objective of this study was to evaluate the rate and predictive factors of evolution to post hemorrhagic hydrocephalus (PHH) requiring a shunt, in newborns with IVH and to report their neurodevelopmental outcomes at 2 years of age.

METHODS

Among all preterm newborns admitted to the department of neonatalogy at Rouen University Hospital, France between January 2000 and December 2013, 122 had an IVH and were included in the study. Newborns with grade 1 IVH according to the Papile classification were excluded.

RESULTS

At 2-year, 18% (n = 22) of our IVH cohort required permanent cerebro spinal fluid (CSF) derivation. High IVH grade, low gestational age at birth and increased head circumference were risk factors for PHH. The rate of death of IVH was 36.9% (n = 45). The rate of cerebral palsy was 55.9% (n = 43) in the 77 surviving patients (49.4%). Risk factors for impaired neurodevelopment were high grade IVH and increased head circumference.

CONCLUSION

High IVH grade was strongly correlated with death and neurodevelopmental outcome. The impact of an increased head circumference highlights the need for early management. CSF biomarkers and new medical treatments such as antenatal magnesium sulfate have emerged and could predict and improve the prognosis of these newborns with PHH.

The oscillatory flow of the cerebrospinal fluid in the Sylvian aqueduct and the prepontine cistern measured with phase contrast MRI in children with hydrocephalus-a preliminary report

INTRODUCTION

Recognizing patients with ventriculomegaly who are at risk of developing acute hydrocephalus presents a challenge for the clinician. The association between disturbed cerebrospinal fluid flow (CSF) and impaired brain compliance may play a role in the pathogenesis of hydrocephalus. Phase contrast MRI is a noninvasive technique which can be used to assess CSF parameters. The aim of the work is to evaluate the effectiveness of phase contrast MRI in recognizing patients at risk of acute hydrocephalus, based on measuring the pulsatile CSF flow parameters in the Sylvian aqueduct and prepontine cistern in children with ventriculomegaly.

AIM

The aim of the work is to characterize the parameters of cerebrospinal fluid (CSF) flow in the Sylvian aqueduct and prepontine cistern in children with ventriculomegaly with regard to patient age and symptoms. We hypothesize that the relationship between CSF flow parameters in these two regions will vary according to analyzed factors and it will allow to recognize children at risk of hydrocephalus.

MATERIALS AND METHODS

A group of 26 children with ventriculomegaly (five girls and 21 boys) underwent phase contrast MRI examinations (Philips 3T Achieva with Q-flow integral application). Amplitudes of average and peak velocities of the CSF flow through the Sylvian aqueduct and prepontine cistern were used to calculate ratios of oscillation and peak velocities, respectively. The relationship between the oscillation coefficient, the peak velocity coefficient, and stroke volume was then assessed in accordance with age and clinical symptoms.

RESULTS

The peak velocity coefficient was significantly higher in patients with hyper-oscillating flow through the Sylvian aqueduct (3.04 ± 3.37 vs. 0.54 ± 0.28; p = 0.0094). Moreover, these patients tended to develop symptoms more often (p = 0.0612). No significant age-related changes were observed in CSF flow parameters.

CONCLUSION

Phase contrast MRI is a useful tool for noninvasive assessment of CSF flow parameters. The application of coefficients instead of direct values seems to better represent hemodynamic conditions in the ventricular system. However, further studies are required to evaluate their clinical significance and normal limits.

Opportunities in posthemorrhagic hydrocephalus research: outcomes of the Hydrocephalus Association Posthemorrhagic Hydrocephalus Workshop

The Hydrocephalus Association Posthemorrhagic Hydrocephalus Workshop was held on July 25 and 26, 2016 at the National Institutes of Health. The workshop brought together a diverse group of researchers including pediatric neurosurgeons, neurologists, and neuropsychologists with scientists in the fields of brain injury and development, cerebrospinal and interstitial fluid dynamics, and the blood-brain and blood-CSF barriers. The goals of the workshop were to identify areas of opportunity in posthemorrhagic hydrocephalus research and encourage scientific collaboration across a diverse set of fields. This report details the major themes discussed during the workshop and research opportunities identified for posthemorrhagic hydrocephalus. The primary areas include (1) preventing intraventricular hemorrhage, (2) stopping primary and secondary brain damage, (3) preventing hydrocephalus, (4) repairing brain damage, and (5) improving neurodevelopment outcomes in posthemorrhagic hydrocephalus.