Neonatal high pressure hydrocephalus is associated with elevation of pro-inflammatory cytokines IL-18 and IFNgamma in cerebrospinal fluid

Pro-inflammatory cerebrospinal fluid profile of neonates with intraventricular hemorrhage: clinical relevance and contrast with CNS infection

BACKGROUND

Interpretation of cerebrospinal fluid (CSF) studies can be challenging in preterm infants. We hypothesized that intraventricular hemorrhage (IVH), post-hemorrhagic hydrocephalus (PHH), and infection (meningitis) promote pro-inflammatory CSF conditions reflected in CSF parameters.

METHODS

Biochemical and cytological profiles of lumbar CSF and peripheral blood samples were analyzed for 81 control, 29 IVH grade 1/2 (IVH1/2), 13 IVH grade 3/4 (IVH3/4), 15 PHH, 20 culture-confirmed bacterial meningitis (BM), and 27 viral meningitis (VM) infants at 36.5 ± 4 weeks estimated gestational age.

RESULTS

PHH infants had higher (p < 0.02) CSF total cell and red blood cell (RBC) counts compared to control, IVH1/2, BM, and VM infants. No differences in white blood cell (WBC) count were found between IVH3/4, PHH, BM, and VM infants. CSF neutrophil counts increased (p ≤ 0.03) for all groups compared to controls except IVH1/2. CSF protein levels were higher (p ≤ 0.02) and CSF glucose levels were lower (p ≤ 0.003) for PHH infants compared to all other groups. In peripheral blood, PHH infants had higher (p ≤ 0.001) WBC counts and lower (p ≤ 0.03) hemoglobin and hematocrit than all groups except for IVH3/4.

CONCLUSIONS

Similarities in CSF parameters may reflect common pathological processes in the inflammatory response and show the complexity associated with interpreting CSF profiles, especially in PHH and meningitis/ventriculitis.

Posthemorrhagic hydrocephalus associates with elevated inflammation and CSF hypersecretion via activation of choroidal transporters

INTRODUCTION

Posthemorrhagic hydrocephalus (PHH) often develops following hemorrhagic events such as intraventricular hemorrhage (IVH) and subarachnoid hemorrhage (SAH). Treatment is limited to surgical diversion of the cerebrospinal fluid (CSF) since no efficient pharmacological therapies are available. This limitation follows from our incomplete knowledge of the molecular mechanisms underlying the ventriculomegaly characteristic of PHH. Here, we aimed to elucidate the molecular coupling between a hemorrhagic event and the subsequent PHH development, and reveal the inflammatory profile of the PHH pathogenesis.

METHODS

CSF obtained from patients with SAH was analyzed for inflammatory markers using the proximity extension assay (PEA) technique. We employed an in vivo rat model of IVH to determine ventricular size, brain water content, intracranial pressure, and CSF secretion rate, as well as for transcriptomic analysis. Ex vivo radio-isotope assays of choroid plexus transport were employed to determine the direct effect of choroidal exposure to blood and inflammatory markers, both with acutely isolated choroid plexus and after prolonged exposure obtained with viable choroid plexus kept in tissue culture conditions.

RESULTS

The rat model of IVH demonstrated PHH and associated CSF hypersecretion. The Na+/K+-ATPase activity was enhanced in choroid plexus isolated from IVH rats, but not directly stimulated by blood components. Inflammatory markers that were elevated in SAH patient CSF acted on immune receptors upregulated in IVH rat choroid plexus and caused Na+/K+/2Cl- cotransporter 1 (NKCC1) hyperactivity in ex vivo experimental conditions.

CONCLUSIONS

CSF hypersecretion may contribute to PHH development, likely due to hyperactivity of choroid plexus transporters. The hemorrhage-induced inflammation detected in CSF and in the choroid plexus tissue may represent the underlying pathology. Therapeutic targeting of such pathways may be employed in future treatment strategies towards PHH patients.

The association of Edaravone with shunt surgery improves behavioral performance, reduces astrocyte reaction and apoptosis, and promotes neuroprotection in young hydrocephalic rats

The neuroprotective effect of Edaravone in young hydrocephalic rats associated with a CSF derivation system was evaluated. The drug has already been shown to be beneficial in experimental hydrocephalus, but the combination of this drug with shunt surgery has not yet been investigated. Fifty-seven-day-old Wistar rats submitted to hydrocephalus by injection of kaolin in the cisterna magna were used and divided into five groups: control (n = 10), hydrocephalic (n = 10), hydrocephalic treated with Edaravone (20 mg/kg/day) (n = 10), hydrocephalic treated with shunt (n = 10) and hydrocephalic treated with shunt and Edaravone (n = 10). Administration of the Edaravone was started 24 h after hydrocephalus induction (P1) and continued until the experimental endpoint (P21). The CSF shunt surgery was performed seven days after hydrocephalus induction (P7). Open-field tests, histological evaluation by hematoxylin and eosin, immunohistochemistry by Caspase-3 and GFAP, and ELISA biochemistry by GFAP were performed. Edaravone reduced reactive astrogliosis in the corpus callosum and germinal matrix (p < 0.05). When used alone or associated with CSF shunt surgery, the drug decreased the cell death process (p < 0.0001) and improved the morphological aspect of the astroglia (p < 0.05). The results showed that Edaravone associated with CSF bypass surgery promotes neuroprotection in young hydrocephalic rats by reducing reactive astrogliosis and decreasing cell death.

Elevated CSF inflammatory markers in patients with idiopathic normal pressure hydrocephalus do not promote NKCC1 hyperactivity in rat choroid plexus

BACKGROUND

Idiopathic normal pressure hydrocephalus (iNPH) is a potentially reversible neurological condition of unresolved etiology characterized by a clinical triad of symptoms; gait disturbances, urinary incontinence, and cognitive deterioration. In the present study, we aimed to elucidate the molecular coupling between inflammatory markers and development of iNPH and determine whether inflammation-induced hyperactivity of the choroidal Na⁺/K⁺/2Cl^- cotransporter (NKCC1) that is involved in cerebrospinal fluid (CSF) secretion could contribute to the iNPH pathogenesis.

METHODS

Lumbar CSF samples from 20 iNPH patients (10 with clinical improvement upon CSF shunting, 10 without clinical improvement) and 20 elderly control subjects were analyzed with the novel proximity extension assay technique for presence of 92 different inflammatory markers. RNA-sequencing was employed to delineate choroidal abundance of the receptors for the inflammatory markers found elevated in the CSF from iNPH patients. The ability of the elevated inflammatory markers to modulate choroidal NKCC1 activity was determined by addition of combinations of rat version of these in ex vivo experiments on rat choroid plexus.

RESULTS

11 inflammatory markers were significantly elevated in the CSF from iNPH patients compared to elderly control subjects: CCL28, CCL23, CCL3, OPG, CXCL1, IL-18, IL-8, OSM, 4E-BP1, CXCL6, and Flt3L. One inflammatory marker, CDCP1, was significantly decreased in iNPH patients compared to control subjects. None of the inflammatory markers differed significantly when comparing iNPH patients with and without clinical improvement upon CSF shunting. All receptors for the elevated inflammatory markers were expressed in the rat and human choroid plexus, except CCR4 and CXCR1, which were absent from the rat choroid plexus. None of the elevated inflammatory markers found in the CSF from iNPH patients modulated the choroidal NKCC1 activity in ex vivo experiments on rat choroid plexus.

CONCLUSION

The CSF from iNPH patients contains elevated levels of a subset of inflammatory markers. Although the corresponding inflammatory receptors are, in general, expressed in the choroid plexus of rats and humans, their activation did not modulate the NKCC1-mediated fraction of choroidal CSF secretion ex vivo. The molecular mechanisms underlying ventriculomegaly in iNPH, and the possible connection to inflammation, therefore remains to be elucidated.

The impact of hypoxia on blood-brain, blood-CSF, and CSF-brain barriers

The blood-brain barrier (BBB), blood-cerebrospinal fluid (CSF) barrier (BCSFB), and CSF-brain barriers (CSFBB) are highly regulated barriers in the central nervous system comprising complex multicellular structures that separate nerves and glia from blood and CSF, respectively. Barrier damage has been implicated in the pathophysiology of diverse hypoxia-related neurological conditions, including stroke, multiple sclerosis, hydrocephalus, and high-altitude cerebral edema. Much is known about the damage to the BBB in response to hypoxia, but much less is known about the BCSFB and CSFBB. Yet, it is known that these other barriers are implicated in damage after hypoxia or inflammation. In the 1950s, it was shown that the rate of radionucleated human serum albumin passage from plasma to CSF was five times higher during hypoxic than normoxic conditions in dogs, due to BCSFB disruption. Severe hypoxia due to administration of the bacterial toxin lipopolysaccharide is associated with disruption of the CSFBB. This review discusses the anatomy of the BBB, BCSFB, and CSFBB and the impact of hypoxia and associated inflammation on the regulation of those barriers.

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.

Relationship Between Oxidative Stress, Tau Level and Antioxidant Mechanisms of the KEAP-1/NRF-2/HO-1 in Children with Hydrocephalus

BACKGROUND

Hydrocephalus is a complex neurologic disorder which has a widespread impact on the central nervous system, and a multifactor disease which effect the CSF dynamics and causes severe neurological impairments in children. The pathophysiology of hydrocephalus is not fully understood. However, increasing evidence suggests that oxidative stress may be an important factor in the pathogenesis of hydrocephalus.

OBJECTIVE

The purpose of this study is to investigate the relationship of KEAP-1/NRF-2/HO-1 pathway, one of the main regulators of the antioxidant system in the hydrocephalus pathology, on oxidative stress and tau protein level.

METHODS

The study included 32 patients with hydrocephalus and 32 healthy controls. KEAP-1, NRF-2, HO-1, TAU, and MPO levels are measured using ELISA method TAS, TOS, Total THIOL colorimetric method.

RESULTS

KEAP-1, TAS, Total THIOL levels were found significantly low in the hydrocephalus group compared to the control group. Nevertheless, it is identified in the hydrocephalus group that the NRF-2, HO-1, TAU, MPO, TOS, and OSI levels were significantly elevated.

CONCLUSION

In conclusion, although KEAP-1/NRF-2/HO-1 pathway is activated in patients with hydrocephalus, it is identified that the antioxidant defense system is insufficient, and ultimately leads to elevated oxidative stress. The elevation in the tau level may be an indicator of oxidative stress induced neurodegenerative damage.

Fetal brain damage in congenital hydrocephalus

BACKGROUND

Congenital hydrocephalus (HCP) is a developmental brain disorder characterized by the abnormal accumulation of cerebrospinal fluid within the ventricles. It is caused by genetic and acquired factors that start during early embryogenesis with disruption of the neurogerminal areas. As might be expected, early-onset hydrocephalus alters the process of brain development leading to irreparable neurological deficit. A primary alteration of the ependyma/neural stem cells (affecting vesicle trafficking and abnormal cell junctions) leads to its loss or denudation and translocation of neural progenitor cells (NPCs) and neural stem cells (NSCs) into the cerebrospinal fluid (CSF). Under these abnormal conditions, morphological and functional processes, underlying the concept of astroglial reaction, are initiated in an attempt to recover homeostasis in the periventricular zone. This astroglial reaction includes astrocyte hypertrophy, hyperplasia, and development of a new layer with reorganized functional features that resemble the ependyma. Despite decades of research, there is a lack of information concerning the biological basis of the brain abnormalities that are associated with HCP.

DISCUSSION

The present review of current literature discusses the neuropathological changes during gestation following the onset of congenital hydrocephalus and the unanswered questions into the pathophysiology of the disease. A better understanding of those missing points might help create novel therapeutic strategies that can reverse or even prevent the ultimate neurological impairment that affects this population and improve long-term clinical outcome.

Collection and Analyses of Cerebrospinal Fluid for Pediatric Translational Research

Cerebrospinal fluid sample collection and analysis is imperative to better elucidate central nervous system injury and disease in children. Sample collection methods are varied and carry with them certain ethical and biologic considerations, complications, and contraindications. Establishing best practices for sample collection, processing, storage, and transport will ensure optimal sample quality. Cerebrospinal fluid samples can be affected by a number of factors including subject age, sampling method, sampling location, volume extracted, fraction, blood contamination, storage methods, and freeze-thaw cycles. Indicators of sample quality can be assessed by matrix-associated laser desorption/ionization time-of-flight mass spectrometry and include cystatin C fragments, oxidized proteins, prostaglandin D synthase, and evidence of blood contamination. Precise documentation of sample collection processes and the establishment of meticulous handling procedures are essential for the creation of clinically relevant biospecimen repositories. In this review we discuss the ethical considerations and best practices for cerebrospinal fluid collection, as well as the influence of preanalytical factors on cerebrospinal fluid analyses. Cerebrospinal fluid biomarkers in highly researched pediatric diseases or disorders are discussed.

Behavioral and Biochemical Features of the Course and Surgical Treatment of Experimental Obstructive Hydrocephalus in Young Rats

INTRODUCTION

Hydrocephalus is a multifactorial disease, affecting the dynamics of cerebrospinal fluid (CSF) and leading to severe neurological impairment in children; in spite of the recent advances in hydrocephalus research, it has many physiopathological aspects that still remain poorly understood, especially after treatment.

OBJECTIVES

To analyze the clinical, radiological, histopathological, and biochemical aspects of kaolin-induced hydrocephalus in an experimental model, both in the acute phase and after shunt treatment, by means of behavioral tests, magnetic resonance imaging (MRI) scans, histopathological studies, and level of inflammatory interleukins in the CSF.

METHODS

Seven-day-old Wistar rats were used and subdivided into three subgroups: treated hydrocephalic (n = 24), untreated hydrocephalic (n = 17), and controls (n = 5). The hydrocephalic groups underwent cisternal injection of 15% kaolin for induction of hydrocephalus at 7 days of age. The treated group was submitted to a ventricular-subcutaneous shunt (VSCS) 1 week after induction. All animals were euthanized at 21 days of age. They underwent motor function and memory testing as well as brain MRI scans. Histopathological analysis for glial fibrillary acidic protein and Ki-67 was done, and CSF was collected for measurement of IL-1β, IL-6, and TNF-α.

RESULTS

The average time to reach the water maze platform was highest in the untreated hydrocephalic group. The magnetization transfer rates were 37.21 and 33.76 before and after shunting, respectively. The mean astrocyte counts were 2.45, 1.36, and 90.5 for shunted, untreated, and control animals, respectively. The mean CSF IL-1β concentrations were 62.3 and 249.6 pg/mL, the average IL-6 levels were 104.2 and 364.7 pg/mL, and the average TNF-α values were 4.9 and 170.5 pg/mL for the treated hydrocephalic group and the untreated group, respectively.

CONCLUSIONS

Pups treated with a CSF shunt showed better performance on memory tests. VSCS did not revert demyelination caused by hydrocephalus. Likewise, reactive astrocytosis and cell proliferation over the germinal matrix were not reversed after shunting. Hydrocephalic animals had raised levels of inflammatory interleukins, which returned to normal after treatment.

Blood-brain barrier and foetal-onset hydrocephalus, with a view on potential novel treatments beyond managing CSF flow

Despite decades of research, no compelling non-surgical therapies have been developed for foetal hydrocephalus. So far, most efforts have pointed to repairing disturbances in the cerebrospinal fluid (CSF) flow and to avoid further brain damage. There are no reports trying to prevent or diminish abnormalities in brain development which are inseparably associated with hydrocephalus. A key problem in the treatment of hydrocephalus is the blood–brain barrier that restricts the access to the brain for therapeutic compounds or systemically grafted cells. Recent investigations have started to open an avenue for the development of a cell therapy for foetal-onset hydrocephalus. Potential cells to be used for brain grafting include: (1) pluripotential neural stem cells; (2) mesenchymal stem cells; (3) genetically-engineered stem cells; (4) choroid plexus cells and (5) subcommissural organ cells. Expected outcomes are a proper microenvironment for the embryonic neurogenic niche and, consequent normal brain development.

Cerebrospinal fluid biomarkers of infantile congenital hydrocephalus

Introduction

Hydrocephalus is a complex neurological disorder with a pervasive impact on the central nervous system. Previous work has demonstrated derangements in the biochemical profile of cerebrospinal fluid (CSF) in hydrocephalus, particularly in infants and children, in whom neurodevelopment is progressing in parallel with concomitant neurological injury. The objective of this study was to examine the CSF of children with congenital hydrocephalus (CHC) to gain insight into the pathophysiology of hydrocephalus and identify candidate biomarkers of CHC with potential diagnostic and therapeutic value.

Methods

CSF levels of amyloid precursor protein (APP) and derivative isoforms (sAPPα, sAPPβ, Aβ₄₂), tau, phosphorylated tau (pTau), L1CAM, NCAM-1, aquaporin 4 (AQP4), and total protein (TP) were measured by ELISA in 20 children with CHC. Two comparative groups were included: age-matched controls and children with other neurological diseases. Demographic parameters, ventricular frontal-occipital horn ratio, associated brain malformations, genetic alterations, and surgical treatments were recorded. Logistic regression analysis and receiver operating characteristic curves were used to examine the association of each CSF protein with CHC.

Results

CSF levels of APP, sAPPα, sAPPβ, Aβ₄₂, tau, pTau, L1CAM, and NCAM-1 but not AQP4 or TP were increased in untreated CHC. CSF TP and normalized L1CAM levels were associated with FOR in CHC subjects, while normalized CSF tau levels were associated with FOR in control subjects. Predictive ability for CHC was strongest for sAPPα, especially in subjects ≤12 months of age (p<0.0001 and AUC = 0.99), followed by normalized sAPPβ (p = 0.0001, AUC = 0.95), tau, APP, and L1CAM. Among subjects ≤12 months, a normalized CSF sAPPα cut-point of 0.41 provided the best prediction of CHC (odds ratio = 528, sensitivity = 0.94, specificity = 0.97); these infants were 32 times more likely to have CHC.

Conclusions

CSF proteins such as sAPPα and related proteins hold promise as biomarkers of CHC in infants and young children, and provide insight into the pathophysiology of CHC during this critical period in neurodevelopment.

Diffusion tensor imaging detects early brain microstructure changes before and after ventriculoperitoneal shunt in children with high intracranial pressure hydrocephalus

To explore the use of diffusion tensor imaging (DTI) parameters in the quantitative assessment of early brain microstructure changes before and after ventriculoperitoneal shunt in children with high intracranial pressure hydrocephalus.Ten patients with communicating hydrocephalus (age: 2-36 months) and 14 age-/gender-matched controls (age: 2-36 months) were enrolled in this study. All patients underwent the ventriculoperitoneal shunt procedure. The imaging data were collected before and 3 months after the operation. Regions of interests (ROIs) included the white matter near the frontal horn of the lateral ventricles (FHLV), the occipital horn of the lateral ventricles (OHLV), occipital subcortical (OS) area, frontal subcortical (FS) area, and thalamus. Fractional anisotropies (FA) and apparent diffusion coefficients (ADC) of the ROIs before and after ventriculoperitoneal shunt were compared between the patients and the controls.Three months after surgery, the patients recovered from the surgery with ameliorated intracranial pressure and slight improvement of clinical intelligence scale and motor scale. Before ventriculoperitoneal shunt, the FA values (except the right FHLV) were significantly decreased and the ADC values were significantly increased in the patients with hydrocephalus, compared with the controls. After the ventriculoperitoneal shunt, the FA values in the FHLV and OHLV of the patients were similar to the controls, but the FA values in other ROIs were still significantly lower than controls. The ADC values in the FS and OS white matter areas of the patients were similar to the controls; however, the ADC values in other ROIs were still significantly higher in patients.The increase of FA and the reduction in ADC in the ROIs preceded the clinical function improvement in patients with high intracranial pressure hydrocephalus and reflected the early changes in brain tissue microstructure, such as the compression of the white matter areas in the ROIs.

High fibrosis indices in cerebrospinal fluid of patients with shunt-dependent post-traumatic chronic hydrocephalus

Objective

A possible relationship between fibrosis along the route of cerebrospinal fluid (CSF) flow and the subsequent development of hydrocephalus has been indicated in previous studies. These changes in the fibrosis index may reflect the severity of hydrocephalus and could potentially become a diagnostic tool. The object of this study was to analyze the levels of procollagen type I C-terminal propeptide (PICP), procollagen type III N-terminal propeptide (PIIINP), hyaluronic acid (HA), and laminin (LN) in the CSF of patients with post-traumatic hydrocephalus and determine the significance of their presence.

Subjects and methods

Forty-four patients were included in the study: 24 patients with shunt-dependent post-traumatic hydrocephalus (group A - hydrocephalus group); ten brain trauma patients without any sign of hydrocephalus (group B - trauma group); ten patients without brain trauma and hydrocephalus (group C - normal control group). CSF levels of PICP, PIIINP, HA, LN and transforming growth factor-β1(TGF-β1) were detected using enzyme-linked immunosorbent assay (ELISA).

Results

Levels of PICP, PIIINP, HA, and LN in the group of hydrocephalus patients were significantly higher than those in the post-trauma patients without hydrocephalus (p < 0.05) and normal control patients (p < 0.05). Moreover, the increased levels of PICP, PIIINP, HA, and LN were positively correlated with the level of TGF-β1 (p < 0.05).

Conclusion

We demonstrated an increase of fibrosis factors including PICP, PIIINP, HA, and LN, that was positively correlated with TGF-β1 levels. This indicates an important role for the process of fibrosis in the development of post-traumatic chronic hydrocephalus and shows the potential utility of PICP, PIIINP, HA, and LN as a diagnostic index in shunt-dependent post-traumatic chronic hydrocephalus.

Hydrocephalus in children

Hydrocephalus is a common disorder of cerebral spinal fluid (CSF) physiology resulting in abnormal expansion of the cerebral ventricles. Infants commonly present with progressive macrocephaly whereas children older than 2 years generally present with signs and symptoms of intracranial hypertension. The classic understanding of hydrocephalus as the result of obstruction to bulk flow of CSF is evolving to models that incorporate dysfunctional cerebral pulsations, brain compliance, and newly characterised water-transport mechanisms. Hydrocephalus has many causes. Congenital hydrocephalus, most commonly involving aqueduct stenosis, has been linked to genes that regulate brain growth and development. Hydrocephalus can also be acquired, mostly from pathological processes that affect ventricular outflow, subarachnoid space function, or cerebral venous compliance. Treatment options include shunt and endoscopic approaches, which should be individualised to the child. The long-term outcome for children that have received treatment for hydrocephalus varies. Advances in brain imaging, technology, and understanding of the pathophysiology should ultimately lead to improved treatment of the disorder.

Increased levels of tumour necrosis factor alpha (TNFα) but not transforming growth factor-beta 1 (TGFβ1) are associated with the severity of congenital hydrocephalus in the hyh mouse

AIMS

Here, we tested the hypothesis that glial responses via the production of cytokines such as transforming growth factor-beta 1 (TGFβ1) and tumour necrosis factor alpha (TNFα), which play important roles in neurodegenerative diseases, are correlated with the severity of congenital hydrocephalus in the hyh mouse model. We also searched for evidence of this association in human cases of primary hydrocephalus.

METHODS

Hyh mice, which exhibit either severe or compensated long-lasting forms of hydrocephalus, were examined and compared with wild-type mice. TGFβ1, TNFα and TNFαR1 mRNA levels were quantified using real-time PCR. TNFα and TNFαR1 were immunolocalized in the brain tissues of hyh mice and four hydrocephalic human foetuses relative to astroglial and microglial reactions.

RESULTS

The TGFβ1 mRNA levels were not significantly different between hyh mice exhibiting severe or compensated hydrocephalus and normal mice. In contrast, severely hydrocephalic mice exhibited four- and two-fold increases in the mean levels of TNFα and TNFαR1, respectively, compared with normal mice. In the hyh mouse, TNFα and TNFαR1 immunoreactivity was preferentially detected in astrocytes that form a particular periventricular reaction characteristic of hydrocephalus. However, these proteins were rarely detected in microglia, which did not appear to be activated. TNFα immunoreactivity was also detected in the glial reaction in the small group of human foetuses exhibiting hydrocephalus that were examined.

CONCLUSIONS

In the hyh mouse model of congenital hydrocephalus, TNFα and TNFαR1 appear to be associated with the severity of the disease, probably mediating the astrocyte reaction, neurodegenerative processes and ischaemia.

Procollagen Type I C-terminal propeptide, procollagen Type III N-terminal propeptide, hyaluronic acid, and laminin in the cerebrospinal fluid of rats with communicating hydrocephalus

OBJECT

Fibrosis along the route of CSF flow is indicated by the development of hydrocephalus. The changes of fibrosis index might reflect the level of hydrocephalus and even become a diagnostic index of hydrocephalus. The object of this study was to analyze the levels of procollagen Type I C-terminal propeptide (PICP), procollagen Type III N-terminal propeptide (PIIINP), hyaluronic acid (HA), and laminin (LN) and their significance in the CSF of communicating hydrocephalus rat models.

METHODS

Thirty adult Sprague-Dawley rats were randomly divided into 3 groups: hydrocephalus group (20 rats) with intraventricular kaolin injections, sham control group (5 rats) with saline injections, and normal group (5 rats) without any processing. The levels of PICP, PIIINP, HA, and LN in the CSF were detected using ELISA.

RESULTS

Levels of PICP, PIIINP, HA, and LN in the hydrocephalus group were significantly higher than those in the saline control group (p < 0.05). It was revealed by correlation analysis that the increase was positively correlated with the severity of ventricular dilation.

CONCLUSIONS

Results indicated that PICP, PIIINP, HA, and LN continue to rise dramatically in experimental hydrocephalus and may serve as the diagnostic index of hydrocephalus.

Cytokines and posthemorrhagic ventricular dilation in premature infants

OBJECTIVE

To determine in extremely low-birth-weight infants if elevated blood interferon-γ (IFN-γ), interleukin (IL)-1β, IL-18, tumor necrosis factor-α (TNF-α), and transforming growth factor-β are associated with need for shunt following severe intraventricular hemorrhage (IVH) or with ventricular dilation following milder grades/no IVH.

STUDY DESIGN

Whole blood cytokines were measured on postnatal days 1, 3, 7, 14, and 21. Maximum IVH grade in the first 28 days, and shunt surgery or ventricular dilation on subsequent ultrasound (28 days' to 36 weeks' postmenstrual age) were determined.

RESULTS

Of 902 infants in the National Institute of Child Health and Human Development Neonatal Research Network Cytokine study who survived to 36 weeks or discharge, 3.1% had shunts. Of the 12% of infants with severe (grade III to IV) IVH, 26% had a shunt associated with elevated TNF-α. None of the infants without IVH (69%) or with grade I (12%) or II (7%) IVH received shunts, but 8.4% developed ventricular dilation, associated with lower IFN-γ and higher IL-18.

CONCLUSION

Statistically significant but clinically nondiscriminatory alterations in blood cytokines were noted in infants with severe IVH who received shunts and in those without severe IVH who developed ventricular dilation. Blood cytokines are likely associated with brain injury but may not be clinically useful as biomarkers for white matter damage.

Increased CSF osmolarity reversibly induces hydrocephalus in the normal rat brain

BACKGROUND

Hydrocephalus is a central nervous system (CNS) disorder characterized by the abnormal accumulation of cerebrospinal fluid (CSF) in cerebral ventricles, resulting in their dilatation and associated brain tissue injury. The pathogenesis of hydrocephalus remains unclear; however, recent reports suggest the possible involvement of abnormal osmotic gradients. Here we explore the kinetics associated with manipulating CSF osmolarity on ventricle volume (VV) in the normal rat brain.

METHODS

CSF was made hyper-osmotic by introducing 10KD dextran into the lateral ventricle, either by acute injection at different concentrations or by chronic infusion at a single concentration. The induction and withdrawal kinetics of dextran infusion on VV were explored in both contexts.

RESULTS

Acute intraventricular injection of dextran caused a rapid increase in VV which completely reversed within 24 hours. These kinetics are seemingly independent of CSF osmolarity across a range spanning an order of magnitude; however, the magnitude of the transient increase in VV was proportional to CSF osmolarity. By contrast, continuous intraventricular infusion of dextran at a relatively low concentration caused a more gradual increase in VV which was very slow to reverse when infusion was suspended after five days.

CONCLUSION

We conclude that hyperosmolar CSF is sufficient to produce a proportional degree of hydrocephalus in the normal rat brain, and that this phenomenon exhibits hysteresis if CSF hyperosmolarity is persistent. Thus pathologically-induced increases in CSF osmolarity may be similarly associated with certain forms of clinical hydrocephalus. An improved understanding of this phenomenon and its kinetics may facilitate the development of novel therapies for the treatment of clinical hydrocephalus.

Reactive astrocytosis in feline neonatal hydrocephalus: acute, chronic, and shunt-induced changes

PURPOSE

Reactive astrocytosis has been implicated in injury and recovery patterns associated with hydrocephalus. To investigate temporal changes in astrogliosis during the early progression of hydrocephalus, after shunting, and after long-term ventriculomegaly, glial fibrillary protein (GFAP) levels were analyzed in a feline model.

METHODS

Obstructive hydrocephalus was induced in 10-day-old kittens by intracisternal injections of 25% kaolin. Acute non-shunted animals were killed 15 days post-kaolin injection to represent the pre-shunt condition. Shunt-treated animals received ventriculoperitoneal shunts 15 days post-injection and were killed 10 or 60 days later to represent short- and long-term recovery periods. Chronic untreated animals had Ommaya reservoirs implanted 15 days post-kaolin, which were tapped intermittently until they were killed 60 days later. Ventriculomegaly was monitored by neuroimaging before and after shunting and at death. RNA and total protein from primary visual cortex were analyzed by Northern and Western blotting.

RESULTS

GFAP RNA and protein levels for acute and chronic non-shunted hydrocephalic animals were 77% and 247% (p < 0.01) and 659% (p < 0.05) and 871% (p < 0.05) higher than controls, respectively. Shunted animals with short-term recovery demonstrated a mismatch in GFAP levels, with RNA expression decreasing 26% and protein increasing 335% (p < 0.01). Shunted animals with a long-term recovery exhibited GFAP RNA and protein levels 201% and 357% above normal, respectively.

CONCLUSIONS

These results indicate that a reactive astrocytic response continues to rise dramatically in chronic hydrocephalus, suggesting ongoing gliosis and potential damage. Shunting partially ameliorates the continuation of astrogliosis, but does not completely reverse this inflammatory reaction even after a long recovery.

Reactive astrocytosis, microgliosis and inflammation in rats with neonatal hydrocephalus

The deleterious effects of hydrocephalus, a disorder that primarily affects children, include reactive astrocytosis, microgliosis and inflammatory responses; however, the roles that these mechanisms play in the pathophysiology of hydrocephalus are still not clear in terms of cytopathology and gene expression. Therefore we have examined neuroinflammation at both the cellular and the molecular levels in an experimental model of neonatal obstructive hydrocephalus. On post-natal day 1, rats received an intracisternal injection of kaolin to induce hydrocephalus; control animals received saline injections. Prior to sacrifice on post-natal day 22, animals underwent magnetic resonance imaging to quantify ventricular enlargement, and the parietal cortex was harvested for analysis. Immunohistochemistry and light microscopy were performed on 5 hydrocephalic and 5 control animals; another set of 5 hydrocephalic and 5 control animals underwent molecular testing with Western blots and a gene microarray. Scoring of immunoreactivity on a 4-point ranking scale for GFAP and Iba-1 demonstrated an increase in reactive astrocytes and reactive microglia respectively in the hydrocephalic animals compared to controls (2.90±0.11 vs. 0.28±0.26; 2.91±0.11 vs. 0.58±0.23, respectively). Western blots confirmed these results. Microarray analysis identified significant (1.5-fold) changes in 1729 of 33,951 genes, including 26 genes out of 185 genes (26/185) in the cytokine-cytokine receptor interaction pathway, antigen processing and presentation pathways (15/66), and the apoptosis pathway (10/69). Collectively, these results demonstrate alterations in normal physiology and an up-regulation of the inflammatory response. These findings lead to a better understanding of neonatal hydrocephalus and begin to form a baseline for future treatments that may reverse these effects.

Irrigation and intraventricular fibrinolytic therapy for posthemorrhagic ventricular dilatation in preterm infants: does it improve neurodevelopmental outcome?

Evaluation of: Whitelaw A, Jary S, Kmita G et al.: Randomized trial of drainage, irrigation and fibrinolytic therapy for premature infants with posthemorrhagic ventricular dilatation: developmental outcome at 2 years. Pediatrics 125, E852–E858 (2010). The aim of the study was to determine in a randomized trial whether ventricle drainage, irrigation and fibrinolytic therapy (DRIFT) altered the rate of death or severe neurodevelopmental disability at 24 months’ corrected age in preterm infants with posthemorrhagic ventricular dilatation. Of the children assigned to DRIFT, 54% died or were severely disabled, versus 71% in the standard group. Among the survivors, 31% in the DRIFT group had severe cognitive disability (Mental Development Index score <55) versus 59% in the standard group. No differences were found in rates of children with Mental Development Index scores over 70. The study points to a potential meaningful intervention by removing toxic substances from hemorrhagic cerebrospinal fluid. Being a highly invasive intervention, however, further studies are required.

Endoplasmic reticulum stress, inflammation, and perinatal brain damage

Inflammation seems to play a role in the pathogenesis of perinatal brain damage in fetuses/infants born much before term. We raise the possibility that noninflammatory phenomena induce endoplasmic reticulum stress, which, in turn, leads to the unfolded protein response, which is followed by apoptosis-promoting processes and inflammation. Perhaps by these events, noninflammatory stimuli lead to perinatal brain damage.