Induction of communicating hydrocephalus in mice by intrathecal injection of human recombinant transforming growth factor-beta 1

Application of LRG mechanism in normal pressure hydrocephalus

Normal pressure hydrocephalus (NPH) is a prevalent type of hydrocephalus, including secondary normal pressure hydrocephalus (SNPH) and idiopathic normal pressure hydrocephalus (INPH). However, its clinical diagnosis and pathological mechanism are still unclear. Leucine-rich α-2 glycoprotein (LRG) is involved in various human diseases, including cancer, diabetes, cardiovascular disease, and nervous system diseases. Now the physiological mechanism of LRG is still being explored. According to the current research results on LRG, we found that the agency of LRG has much to do with the known pathological process of NPH. This review focuses on analyzing the LRG signaling pathways and the pathological mechanism of NPH. According to the collected literature evidence, we speculated that LRG probably be involved in the pathological process of NPH. Finally, based on the mechanism of LRG and NPH, we also summarized the evidence of molecular targeted therapies for future research and clinical application.

Rodent models of senile normal-pressure hydrocephalus

Cerebrospinal fluid (CSF) and its drainage are crucial in clearing metabolic waste and maintaining the microenvironment of the central nervous system for proper functioning. Normal-pressure hydrocephalus (NPH) is a serious neurological disorder of the elderly with obstruction of CSF flow outside the cerebral ventricles, causing ventriculomegaly. The stasis of CSF in NPH compromises brain functioning. Although treatable, often with shunt implantation for drainage, the outcome depends highly on early diagnosis, which, however, is challenging. The initial symptoms of NPH are hard to be aware of and the complete symptoms overlap with those of other neurological diseases. Ventriculomegaly is not specific to NPH as well. The lack of knowledge on the initial stages in its development and throughout its progression further deters early diagnosis. Thus, we are in dire need for an appropriate animal model for researches into a more thorough understanding of its development and pathophysiology so that we can enhance the diagnosis and therapeutic strategies to improve the prognosis of NPH following treatment. With this, we review the few currently available experimental rodent NPH models for these animals are smaller in sizes, easier in maintenance, and having a rapid life cycle. Among these, a parietal convexity subarachnoid space kaolin injection adult rat model appears promising as it shows a slow onset of ventriculomegaly in association with cognitive and motor disabilities resembling the elderly NPH in humans.

Pathophysiologic mechanisms and strategies for the treatment of post-hemorrhagic hydrocephalus of prematurity

PURPOSE

Post-hemorrhagic hydrocephalus (PHH) of prematurity is a devastating pathology. Neurodevelopmental disabilities, including cognitive and motor deficits are very commonly seen among this population. Thus, there is interest to delineate the pathophysiology of PHH to uncover potential therapeutic targets.

METHODS

We performed a systematic review of the current literature on pathophysiological mechanisms and progressive strategies in the management of post-hemorrhagic hydrocephalus of prematurity. Our literature search identified a total of 58 articles pertaining to the pathophysiology, risk factors and management of post-hemorrhagic hydrocephalus.

RESULTS

Presence of high-grade germinal matrix hemorrhage does not always predict PHH and neither does obstruction of pathways seen on ultrasound or MRI scan. We also describe the management options for posthemorrhagic hydrocephalus, including surgical and non-surgical.

CONCLUSION

We conclude that pathogenesis of post-hemorrhagic hydrocephalus of prematurity is clearly multifactorial and definitive prediction of who will eventually develop PHH continues to be elusive.

When the Blood Hits Your Brain: The Neurotoxicity of Extravasated Blood

Hemorrhage in the central nervous system (CNS), including intracerebral hemorrhage (ICH), intraventricular hemorrhage (IVH), and aneurysmal subarachnoid hemorrhage (aSAH), remains highly morbid. Trials of medical management for these conditions over recent decades have been largely unsuccessful in improving outcome and reducing mortality. Beyond its role in creating mass effect, the presence of extravasated blood in patients with CNS hemorrhage is generally overlooked. Since trials of surgical intervention to remove CNS hemorrhage have been generally unsuccessful, the potent neurotoxicity of blood is generally viewed as a basic scientific curiosity rather than a clinically meaningful factor. In this review, we evaluate the direct role of blood as a neurotoxin and its subsequent clinical relevance. We first describe the molecular mechanisms of blood neurotoxicity. We then evaluate the clinical literature that directly relates to the evacuation of CNS hemorrhage. We posit that the efficacy of clot removal is a critical factor in outcome following surgical intervention. Future interventions for CNS hemorrhage should be guided by the principle that blood is exquisitely toxic to the brain.

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.

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.

Higher Plasma Osteopontin Concentrations Associated with Subsequent Development of Chronic Shunt-Dependent Hydrocephalus After Aneurysmal Subarachnoid Hemorrhage

A matricellular protein osteopontin (OPN) is considered to exert neuroprotective and healing effects on neurovascular injuries in an acute phase of aneurysmal subarachnoid hemorrhage (SAH). However, the relationships between OPN expression and chronic shunt-dependent hydrocephalus (SDHC) have never been investigated. In 166 SAH patients (derivation and validation cohorts, 110 and 56, respectively), plasma OPN levels were serially measured at days1-3, 4-6, 7-9, and 10-12 after aneurysmal obliteration. The OPN levels and clinical factors were compared between patients with and without subsequent development of chronic SDHC. Plasma OPN levels in the SDHC patients increased from days 1-3 to days 4-6 and remained high thereafter, while those in the non-SDHC patients peaked at days 4-6 and then decreased over time. Plasma OPN levels had no correlation with serum levels of C-reactive protein (CRP), a systemic inflammatory marker. Univariate analyses showed that age, modified Fisher grade, acute hydrocephalus, cerebrospinal fluid drainage, and OPN and CRP levels at days 10-12 were significantly different between patients with and without SDHC. Multivariate analyses revealed that higher plasma OPN levels at days 10-12 were an independent factor associated with the development of SDHC, in addition to a more frequent use of cerebrospinal fluid drainage and higher modified Fisher grade at admission. Plasma OPN levels at days 10-12 maintained similar discrimination power in the validation cohort and had good calibration on the Hosmer-Lemeshow goodness-of-fit test. Prolonged higher expression of OPN may contribute to the development of post-SAH SDHC, possibly by excessive repairing effects promoting fibrosis in the subarachnoid space.

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.

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.

Delayed ALK5 inhibition improves functional recovery in neonatal brain injury

Neuroinflammation subsequent to developmental brain injury contributes to a wave of secondary neurodegeneration and to reactive astrogliosis that can inhibit oligodendrocyte progenitor differentiation and subsequent myelination. Here we evaluated the therapeutic efficacy of a small molecule antagonist for a TGFß receptor in a model of moderate perinatal hypoxia-ischemia (H-I). Osmotic pumps containing SB505124, an antagonist of the type 1 TGFß1 receptor ALK5, or vehicle, were implanted three days after H-I induced at postnatal day 6. Perinatal H-I induced selective neuronal death, ventriculomegaly, elevated CNS levels of IL-6 and IL-1α, astrogliosis, and fewer proliferating oligodendrocyte progenitors. Myelination was reduced by ∼50%. Anterograde tracing revealed extensive axonal loss in the corticospinal tract. These alterations correlated with functional impairments across a battery of behavioral tests. All of these parameters were brought back towards normal levels with SB505124 treatment. Notably, SB505124 preserved neurons in the hippocampus and thalamus. Our results indicate that inhibiting ALK5 signaling, even as late as three days after injury, creates an environment that is more permissive for oligodendrocyte maturation and myelination producing significant improvements in neurological outcome. This new therapeutic would be especially appropriate for moderately preterm asphyxiated infants, for whom there is presently no FDA approved neuroprotective therapeutic.

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.

Preventive effects of cilostazol against the development of shunt-dependent hydrocephalus after subarachnoid hemorrhage

OBJECTIVE Chronic hydrocephalus develops in association with the induction of tenascin-C (TNC), a matricellular protein, after aneurysmal subarachnoid hemorrhage (SAH). The aim of this study was to examine if cilostazol, a selective inhibitor of phosphodiesterase Type III, suppresses the development of chronic hydrocephalus by inhibiting TNC induction in aneurysmal SAH patients. METHODS The authors retrospectively reviewed the factors influencing the development of chronic shunt-dependent hydrocephalus in 87 patients with Fisher Grade 3 SAH using multivariate logistic regression analyses. Cilostazol (50 or 100 mg administered 2 or 3 times per day) was administered from the day following aneurysmal obliteration according to the preference of the attending neurosurgeon. As a separate study, the effects of different dosages of cilostazol on the serum TNC levels were chronologically examined from Days 1 to 12 in 38 SAH patients with Fisher Grade 3 SAH. RESULTS Chronic hydrocephalus occurred in 12 of 36 (33.3%), 5 of 39 (12.8%), and 1 of 12 (8.3%) patients in the 0 mg/day, 100 to 200 mg/day, and 300 mg/day cilostazol groups, respectively. The multivariate analyses showed that older age (OR 1.10, 95% CI 1.13-1.24; p = 0.012), acute hydrocephalus (OR 23.28, 95% CI 1.75-729.83; p = 0.016), and cilostazol (OR 0.23, 95% CI 0.05-0.93; p = 0.038) independently affected the development of chronic hydrocephalus. Higher dosages of cilostazol more effectively suppressed the serum TNC levels through Days 1 to 12 post-SAH. CONCLUSIONS Cilostazol may prevent the development of chronic hydrocephalus and reduce shunt surgery, possibly by the inhibition of TNC induction after SAH.

Diffusion tensor imaging with direct cytopathological validation: characterisation of decorin treatment in experimental juvenile communicating hydrocephalus

BACKGROUND

In an effort to develop novel treatments for communicating hydrocephalus, we have shown previously that the transforming growth factor-β antagonist, decorin, inhibits subarachnoid fibrosis mediated ventriculomegaly; however decorin's ability to prevent cerebral cytopathology in communicating hydrocephalus has not been fully examined. Furthermore, the capacity for diffusion tensor imaging to act as a proxy measure of cerebral pathology in multiple sclerosis and spinal cord injury has recently been demonstrated. However, the use of diffusion tensor imaging to investigate cytopathological changes in communicating hydrocephalus is yet to occur. Hence, this study aimed to determine whether decorin treatment influences alterations in diffusion tensor imaging parameters and cytopathology in experimental communicating hydrocephalus. Moreover, the study also explored whether diffusion tensor imaging parameters correlate with cellular pathology in communicating hydrocephalus.

METHODS

Accordingly, communicating hydrocephalus was induced by injecting kaolin into the basal cisterns in 3-week old rats followed immediately by 14 days of continuous intraventricular delivery of either human recombinant decorin (n = 5) or vehicle (n = 6). Four rats remained as intact controls and a further four rats served as kaolin only controls. At 14-days post-kaolin, just prior to sacrifice, routine magnetic resonance imaging and magnetic resonance diffusion tensor imaging was conducted and the mean diffusivity, fractional anisotropy, radial and axial diffusivity of seven cerebral regions were assessed by voxel-based analysis in the corpus callosum, periventricular white matter, caudal internal capsule, CA1 hippocampus, and outer and inner parietal cortex. Myelin integrity, gliosis and aquaporin-4 levels were evaluated by post-mortem immunohistochemistry in the CA3 hippocampus and in the caudal brain of the same cerebral structures analysed by diffusion tensor imaging.

RESULTS

Decorin significantly decreased myelin damage in the caudal internal capsule and prevented caudal periventricular white matter oedema and astrogliosis. Furthermore, decorin treatment prevented the increase in caudal periventricular white matter mean diffusivity (p = 0.032) as well as caudal corpus callosum axial diffusivity (p = 0.004) and radial diffusivity (p = 0.034). Furthermore, diffusion tensor imaging parameters correlated primarily with periventricular white matter astrocyte and aquaporin-4 levels.

CONCLUSIONS

Overall, these findings suggest that decorin has the therapeutic potential to reduce white matter cytopathology in hydrocephalus. Moreover, diffusion tensor imaging is a useful tool to provide surrogate measures of periventricular white matter pathology in communicating hydrocephalus.

Nonsurgical therapy for hydrocephalus: a comprehensive and critical review

Pharmacological interventions have been tested experimentally and clinically to prevent hydrocephalus and avoid the need for shunting beginning in the 1950s. Clinical trials of varied quality have not demonstrated lasting and convincing protective effects through manipulation of cerebrospinal fluid production, diuresis, blood clot fibrinolysis, or manipulation of fibrosis in the subarachnoid compartment, although there remains some promise in the latter areas. Acetazolamide bolus seems to be useful for predicting shunt response in adults with hydrocephalus. Neuroprotection in the situation of established hydrocephalus has been tested experimentally beginning more recently. Therapies designed to modify blood flow or pulsation, reduce inflammation, reduce oxidative damage, or protect neurons are so far of limited success; more experimental work is needed in these areas. As has been recommended for preclinical studies in stroke and brain trauma, stringent conditions should be met for preclinical studies in hydrocephalus.

Pharmacological Preventions of Brain Injury Following Experimental Germinal Matrix Hemorrhage: an Up-to-Date Review

Germinal matrix hemorrhage (GMH) is defined as the rupture of immature blood vessels in the subependymal zone of premature infants with significant mortality and morbidity. Considering the notable social and ecological stress brought by GMH-induced brain injury and sequelae, safe and efficient pharmacological preventions are badly needed. Currently, several appropriate animal models are available to mimic the clinical outcomes of GMH in human patients. In the long run, hemorrhagic strokes are the research target. Previously, we found that minocycline was efficient to alleviate GMH-induced brain edema and posthemorrhagic hydrocephalus (PHH) in rats, which may be closely related to the activation of cannabinoid receptor 2 (CB2R). However, how the two molecules correlate and the underlined molecular pathway remain unknown. To extensively understand current experimental GMH treatment, this literature review critically evaluates existing therapeutic strategies, potential treatments, and potentially involved molecular mechanisms. Each strategy has its own advantages and disadvantages. Some of the mechanisms are still controversial, requiring an increasing number of animal experiments before the therapeutic strategy would be widely accepted.

Soluble Epoxide Hydrolase in Hydrocephalus, Cerebral Edema, and Vascular Inflammation After Subarachnoid Hemorrhage

BACKGROUND AND PURPOSE

Acute communicating hydrocephalus and cerebral edema are common and serious complications of subarachnoid hemorrhage (SAH), whose causes are poorly understood. Using a mouse model of SAH, we determined whether soluble epoxide hydrolase (sEH) gene deletion protects against SAH-induced hydrocephalus and edema by increasing levels of vasoprotective eicosanoids and suppressing vascular inflammation.

METHODS

SAH was induced via endovascular puncture in wild-type and sEH knockout mice. Hydrocephalus and tissue edema were assessed by T2-weighted magnetic resonance imaging. Endothelial activation was assessed in vivo using T2*-weighted magnetic resonance imaging after intravenous administration of iron oxide particles linked to anti-vascular cell adhesion molecule-1 antibody 24 hours after SAH. Behavioral outcome was assessed at 96 hours after SAH with the open field and accelerated rotarod tests.

RESULTS

SAH induced an acute sustained communicating hydrocephalus within 6 hours of endovascular puncture in both wild-type and sEH knockout mice. This was followed by tissue edema, which peaked at 24 hours after SAH and was limited to white matter fiber tracts. sEH knockout mice had reduced edema, less vascular cell adhesion molecule-1 uptake, and improved outcome compared with wild-type mice.

CONCLUSIONS

Genetic deletion of sEH reduces vascular inflammation and edema and improves outcome after SAH. sEH inhibition may serve as a novel therapy for SAH.

Potential neuroprotective role of transforming growth factor β1 (TGFβ1) in the brain

TGFβ1 is a growth factor that is known to be expressed in most neurodegenerative diseases and after vascular accidents in the brain. TGFβ1 downregulates the activity of activated microglia and promotes astrogliosis. It also prevents cell death by a known mechanism dependant on astrocytes and the secretion of the plasminogen activator inhibitor 1 (PAI-1). This mechanism can provide light on what is the mechanism of action of TGFβ1 as a protective factor and it can provide the pharmacological principles in which this pathway could be used with therapeutic purposes. TGFβ1 is upregulated in most neurodegenerative diseases, however, its expression appears dramatically blocked in Huntington's disease, the fastest of those diseases in progress after the onset. This fact suggests that TGFβ1 slows down the neurodegenerative process, preventing tissue damage and neural apoptotic death. However, the exact details of TGFβ1 action are still unknown and the physiological roles on the diseases are still mysterious. Interestingly, all the data regarding the roles of TGFβ1 in health and disease have been also confirmed with the use of transgenic knockouts and TGFβ1 overexpressing mice. What possibly came as a surprise from the study of TGFβ1 overexpressing models is that combining its neuroprotective and antiproliferative effects, this cytokine generates a significant disruption in the hippocampal circuitry with its consequent learning and memory deficit.

Inhibition of transforming growth factor-β attenuates brain injury and neurological deficits in a rat model of germinal matrix hemorrhage

BACKGROUND AND PURPOSE

Transforming growth factor-β (TGF-β) overproduction and activation of the TGF-β pathway are associated with the development of brain injury following germinal matrix hemorrhage (GMH) in premature infants. We examined the effects of GMH on the level of TGF-β1 in a novel rat collagenase-induced GMH model and determined the effect of inhibition of the TGF receptor I.

METHODS

In total, 92 seven-day old (P7) rats were used. Time-dependent effects of GMH on the level of TGF-β1 and TGF receptor I were evaluated by Western blot. A TGF receptor I inhibitor (SD208) was administered daily for 3 days, starting either 1 hour or 3 days after GMH induction. The effects of GMH and SD208 on the TGF-β pathway were evaluated by Western blot at day 3. The effects of GMH and SD208 on cognitive and motor function were also assessed. The effects of TGF receptor I inhibition by SD208 on GMH-induced brain injury and underlying molecular pathways were investigated by Western blot, immunofluorescence, and morphology studies 24 days after GMH.

RESULTS

GMH induced significant delay in development, caused impairment in both cognitive and motor functions, and resulted in brain atrophy in rat subjects. GMH also caused deposition of both vitronectin (an extracellular matrix protein) and glial fibrillary acidic protein in perilesion areas, associated with development of hydrocephalus. SD208 ameliorated GMH-induced developmental delay, improved cognitive and motor functions, and attenuated body weight loss. SD208 also decreased vitronectin and glial fibrillary acidic protein deposition and decreased GMH-induced brain injury.

CONCLUSIONS

Increased level of TGF-β1 and activation of the TGF-β pathway associate with the development of brain injury after GMH. SD208 inhibits GMH-induced activation of the TGF-β pathway and leads to an improved developmental profile, partial recovery of cognitive and motor functions, and attenuation of GMH-induced brain atrophy and hydrocephalus.

Mechanisms of hydrocephalus after neonatal and adult intraventricular hemorrhage

Intraventricular hemorrhage (IVH) is a cause of significant morbidity and mortality and is an independent predictor of a worse outcome in intracerebral hemorrhage (ICH) and germinal matrix hemorrhage (GMH). IVH may result in both injuries to the brain as well as hydrocephalus. This paper reviews evidence on the mechanisms and potential treatments for IVH-induced hydrocephalus. One frequently cited theory to explain hydrocephalus after IVH involves obliteration of the arachnoid villi by microthrombi with subsequent inflammation and fibrosis causing CSF outflow obstruction. Although there is some evidence to support this theory, there may be other mechanisms involved, which contribute to the development of hydrocephalus. It is also unclear whether the causes of acute and chronic hydrocephalus after hemorrhage occur via different mechanisms; mechanical obstruction by blood in the former, and inflammation and fibrosis in the latter. Management of IVH and strategies for prevention of brain injury and hydrocephalus are areas requiring further study. A better understanding of the pathogenesis of hydrocephalus after IVH, may lead to improved strategies to prevent and treat post-hemorrhagic hydrocephalus.

Decorin prevents the development of juvenile communicating hydrocephalus

In post-haemorrhagic and other forms of communicating hydrocephalus, cerebrospinal fluid flow and drainage is obstructed by subarachnoid fibrosis in which the potent fibrogenic cytokine transforming growth factor-β has been aetiologically implicated. Here, the hypothesis that the transforming growth factor-β antagonist decorin has therapeutic potential for reducing fibrosis and ventriculomegaly was tested using a rat model of juvenile communicating hydrocephalus. Hydrocephalus was induced by a single basal cistern injection of kaolin in 3-week-old rats, immediately followed by 3 or 14 days of continuous intraventricular infusion of either human recombinant decorin or phosphate-buffered saline (vehicle). Ventricular expansion was measured by magnetic resonance imaging at Day 14. Fibrosis, transforming growth factor-β/Smad2/3 activation and hydrocephalic brain pathology were evaluated at Day 14 and the inflammatory response at Days 3 and 14 by immunohistochemistry and basic histology. Analysis of ventricular size demonstrated the development of hydrocephalus in kaolin-injected rats but also revealed that continuous decorin infusion prevented ventricular enlargement, such that ventricle size remained similar to that in intact control rats. Decorin prevented the increase in transforming growth factor-β1 and phosphorylated Smad2/3 levels throughout the ventricular system after kaolin injection and also inhibited the deposition of the extracellular matrix molecules, laminin and fibronectin in the subarachnoid space. In addition, decorin protected against hydrocephalic brain damage inferred from attenuation of glial and inflammatory reactions. Thus, we conclude that decorin prevented the development of hydrocephalus in juvenile rats by blocking transforming growth factor-β-induced subarachnoid fibrosis and protected against hydrocephalic brain damage. The results suggest that decorin is a potential clinical therapeutic for the treatment of juvenile post-haemorrhagic communicating hydrocephalus.

Spatial learning transiently disturbed by intraventricular administration of ouabain

The presence of sodium-potassium-adenosine triphosphatase (Na+,K+-ATPase) on the surface of arachnoid cells indicates that active transport of electrolytes and water occurs there. Previously, we accidentally found that intraventricular administration of TGF-beta1 impaired rat spatial learning. Levels of Na+,K+ -ATPase were decreased in arachnoid cells with fibrosis. To characterize the role of the Na+,K+ -ATPase, Wistar rats were intraventricularly administered a total of 200 microl of ouabain, at concentrations of 10(-5), 10(-4) and 10(-3) M, for one week with an osmotic pump, and were examined with a Morris water maze. Latency for reaching the platform did not significantly differ between ouabain-administered rats and controls. Spatial learning was impaired in a dose-dependent manner. Na+,K+ -ATPase activity of arachnoid cells ceased during ouabain administration, and recovered completely three weeks after the end of ouabain administration. The present results suggest that the Na+,K+ -ATPase on the surface of arachnoid cells contributes to maintenance of rat spatial learning.

A murine model of communicating hydrocephalus: Role of TGF-beta1

Subarachnoid haemorrhage (SAH) often causes communicating hydrocephalus. We recently found that intrathecal injection of human recombinant transforming growth factor (hrTGF)-beta1 induced communicating hydrocephalus in mice. In this experiment we examined whether hydrocephalus could be generated in mice by intrathecal injection of autologous serum, which would contain TGF-beta1 in a similar situation to SAH. Mouse serum, plasma and a range of quantities of hrTGF-beta1 were injected intrathecally into 10 day old C57BL/6 mice. The sizes of the lateral ventricles were measured some weeks after injection. The serum induced hydrocephalus which was prevented by additional injection of anti-TGF-beta1 antibody. Immunoblot analysis showed a band of the active form of TGF-beta1 in the serum which was not detected in the plasma. This study therefore suggests that active TGF-beta1 in cerebrospinal fluid after SAH contributes to the generation of communicating hydrocephalus.

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.

The dynamics of brain and cerebrospinal fluid growth in normal versus hydrocephalic mice

OBJECT

Hydrocephalus has traditionally been quantified by linear measures of ventricular size, with adjunct use of cortical mantle thickness. However, clinical outcome depends on cognitive function, which is more directly related to brain volume than these previous measures. The authors sought to quantify the dynamics of brain and ventricular volume growth in normal compared with hydrocephalic mice.

METHODS

Hydrocephalus was induced in 14-day-old C57BL/6 mice by percutaneous injection of kaolin into the cisterna magna. Nine hydrocephalic and 6 normal mice were serially imaged from age 2-12 weeks with a 14.1-T MR imaging unit. Total brain and ventricle volumes were calculated, and linear discriminant analysis was applied.

RESULTS

Two very different patterns of response were seen in hydrocephalic mice compared with mice with normative growth. In one pattern (3 mice) brain growth was normal despite accumulation of CSF, and in the second pattern (6 mice) abnormal brain enlargement was accompanied by increased CSF volume along with parenchymal edema. In this latter pattern, spontaneous ventricular rupture led to normalization of brain volume, implying edema from transmantle pressure gradients. These 2 patterns of hydrocephalus were significantly discriminable using linear discriminant analysis (p < 0.01). In contrast, clinically relevant measurements of head circumference or frontal and occipital horn ratios were unable to discriminate between these patterns.

CONCLUSIONS

This study is, to the authors' knowledge, the first serial quantification of the growth of brain and ventricle volumes in normal versus hydrocephalic development. The authors' findings demonstrate the feasibility of constructing normative curves of brain and fluid growth as complements to normative head circumference curves. By measuring brain volumes, distinct patterns of brain growth and enlargement can be observed, which are more likely linked to cognitive development and clinical outcome than fluid volumes alone.

Relation between TGF-beta 1 levels in cerebrospinal fluid and ETV outcome in premature newborns with posthemorrhagic hydrocephalus

OBJECT

Therapy of posthaemorrhagic hydrocephalus (PHH) by using ventriculo-peritoneal drainage bears considerable rate of complications and remains a challenge in premature newborns. The role of endoscopic third ventriculostomy (ETV) in these patients is unclear, through obstruction is proven in some patients with PHH. Transforming growth factor beta 1 (TGF-beta1) release into the cerebrospinal fluid (CSF) in time of primary bleeding is suggested as one of the possible pathophysiologic reasons of PHH formation. Relation between TGF-beta1 levels and ETV success rate has not been reported yet. The aim of our study is to detect group of patients, according to the levels of TGF-beta1, who have magnetic resonance imaging (MRI)-proven obstruction hydrocephalus without participation of hyporesorption-so that we can expect success of ETV.

METHODS

We followed 29 premature newborns with PHH during 2005-2007, all of them treated by Ommaya reservoir implantation and repeated taps with TGF-beta1 levels examination. In case of persisting hydrocephalus, MRI was performed. In 16 patients with proven obstruction, ETV was performed. We were successful in six patients (37,5%). We evaluated pathophysiological type of hydrocephalus and ETV succes rate and their relation to TGF-beta1 CSF levels.

RESULTS

We have proven statistically relevant probability in diagnosis of hyporesorptive hydrocephalus based on TGF-beta1 level in CSF. Value exceeding 3,296 pg/ml means 81,3% probability of present hyporesorption. Success rate of ETV in patients with MRI-verified obstruction and TGF-beta1 level lower than 3,296 pg/ml was 100% in our series.

CONCLUSION

TGF-beta1 level indicates participation of hyporesorption in hydrocephalus development and its level may influence decision making in ETV for premature newborns with PHH.

Transgenic models for cytokine-induced neurological disease

Considerable evidence supports the idea that cytokines are important mediators of pathophysiologic processes within the central nervous system (CNS). Numerous studies have documented the increased production of various cytokines in the human CNS in a variety of neurological and neuropsychiatric disorders. Deciphering cytokine actions in the intact CNS has important implications for our understanding of the pathogenesis and treatment of these disorders. One approach to address this problem that has been used widely employs transgenic mice with CNS-targeted production of different cytokines. Transgenic production of cytokines in the CNS of mice allows not only for the investigation of complex cellular responses at a localized level in the intact brain but also more closely recapitulates the expression of these mediators as found in disease states. As discussed in this review, the findings show that these transgenic animals exhibit wide-ranging structural and functional deficits that are linked to the development of distinct neuroinflammatory responses which are relatively specific for each cytokine. These cytokine-induced alterations often recapitulate those found in various human neurological disorders not only underscoring the relevance of these models but also reinforcing the clinicopathogenetic significance of cytokines in diseases of the CNS.

Priorities for hydrocephalus research: report from a National Institutes of Health-sponsored workshop

OBJECT

Treatment for hydrocephalus has not advanced appreciably since the advent of cerebrospinal fluid (CSF) shunts more than 50 years ago. Many questions remain that clinical and basic research could address, which in turn could improve therapeutic options. To clarify the main issues facing hydrocephalus research and to identify critical advances necessary to improve outcomes for patients with hydrocephalus, the National Institutes of Health (NIH) sponsored a workshop titled "Hydrocephalus: Myths, New Facts, and Clear Directions." The purpose of this paper is to report on the recommendations that resulted from that workshop.

METHODS

The workshop convened from September 29 to October 1, 2005, in Bethesda, Maryland. Among the 150 attendees was an international group of participants, including experts in pediatric and adult hydrocephalus as well as scientists working in related fields, neurosurgeons, laboratory-based neuroscientists, neurologists, patient advocates, individuals with hydrocephalus, parents, and NIH program and intramural staff. Plenary and breakout sessions covered injury and recovery mechanisms, modeling, biomechanics, diagnosis, current treatment and outcomes, complications, quality of life, future treatments, medical devices, development of research networks and information sharing, and education and career development.

RESULTS

The conclusions were as follows: 1) current methods of diagnosis, treatment, and outcomes monitoring need improvement; 2) frequent complications, poor rate of shunt survival, and poor quality of life for patients lead to unsatisfactory outcomes; 3) investigators and caregivers need additional methods to monitor neurocognitive function and control of CSF variables such as pressure, flow, or pulsatility; 4) research warrants novel interdisciplinary approaches; 5) understanding of the pathophysiological and recovery mechanisms of neuronal function in hydrocephalus is poor, warranting further investigation; and 6) both basic and clinical aspects warrant expanded and innovative training programs.

CONCLUSIONS

The research priorities of this workshop provide critical guidance for future research in hydrocephalus, which should result in advances in knowledge, and ultimately in the treatment for this important disorder and improved outcomes in patients of all ages.

Intranasal delivery of transforming growth factor-beta1 in mice after stroke reduces infarct volume and increases neurogenesis in the subventricular zone

Background

The effect of neurotrophic factors in enhancing stroke-induced neurogenesis in the adult subventricular zone (SVZ) is limited by their poor blood-brain barrier (BBB) permeability.

Intranasal administration is a noninvasive and valid method for delivery of neuropeptides into the brain, to bypass the BBB. We investigated the effect of treatment with intranasal transforming growth factor-β1 (TGF-β1) on neurogenesis in the adult mouse SVZ following focal ischemia. The modified Neurological Severity Scores (NSS) test was used to evaluate neurological function, and infarct volumes were determined from hematoxylin-stained sections. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling (TUNEL) labeling was performed at 7 days after middle cerebral artery occlusion (MCAO). Immunohistochemistry was used to detect bromodeoxyuridine (BrdU) and neuron- or glia-specific markers for identifying neurogenesis in the SVZ at 7, 14, 21, 28 days after MCAO.

Results

Intranasal treatment of TGF-β1 shows significant improvement in neurological function and reduction of infarct volume compared with control animals. TGF-β1 treated mice had significantly less TUNEL-positive cells in the ipsilateral striatum than that in control groups. The number of BrdU-incorporated cells in the SVZ and striatum was significantly increased in the TGF-β1 treated group compared with control animals at each time point. In addition, numbers of BrdU- labeled cells coexpressed with the migrating neuroblast marker doublecortin (DCX) and the mature neuronal marker neuronal nuclei (NeuN) were significantly increased after intranasal delivery of TGF-β1, while only a few BrdU labeled cells co-stained with glial fibrillary acidic protein (GFAP).

Conclusion

Intranasal administration of TGF-β1 reduces infarct volume, improves functional recovery and enhances neurogenesis in mice after stroke. Intranasal TGF-β1 may have therapeutic potential for cerebrovascular disorders.

Expression of TGF-betas in the embryonic nervous system: analysis of interbalance between isoforms

Transforming growth factor-beta (TGF-beta) is a family of growth factors with essential and multiple roles during embryonic development. In mammals, three isoforms (TGF-beta1, TGF-beta2, TGF-beta3) have been described. In the nervous system, the presence of TGF-beta1 has remained undetectable in other structures than meninges and choroids plexus, while TGF-beta2 and TGF-beta3 were considered as the neural members of the family. In the present study, we have analysed the expression pattern of the three isoforms in the neural tube, brain, and spinal cord during development in both mouse and chicken. The data reveal specific patterns for each isoform. This work also shows that both TGF-beta1 and TGF-beta3 are expressed in neural crest cells. In addition, we demonstrate the existence of interbalance between TGF-beta1 and TGF-beta3 with possible functional implications, which, together with the expression of TGF-beta1 in the CNS, represents one of the most important contributions of this work.

Young C3H mice infected with Toxoplasma gondii are a novel experimental model of communicating hydrocephalus

The effects of leptomeningeal inflammation on the development of hydrocephalus are less understood than those of obstructing the flow of cerebrospinal fluid (CSF) in animal models. We succeeded in introducing a novel experimental model of hydrocephalus and analysed changes in histopathology and CSF flow in mice infected with an avirulent Fukaya strain of Toxoplasma gondii (T. gondii). Six to 7 week-old male mice were orally inoculated with a brain homogenate containing ten T. gondii cysts. The cerebral ventricles became enlarged in all C3H/HeN and C57BL/6 mice 4 weeks after T. gondii infection, but mildly in BALB/c mice. In addition to the lateral ventricle, the third and fourth ventricles and Sylvian aqueducts were dilated in all mice. Lymphocytes and monocytes infiltrated the subarachnoid space. Indian ink particles required more time to pass from the lateral ventricle to the cervical lymph nodes, although they reached the subarachnoid space. Computed tomography ventriculography demonstrated that the CSF was not obstructed during passage through the ventricular systems, but contrast remained static in the lateral ventricle only in infected mice. These results indicated that the infected mice developed communicating type hydrocephalus without obstructive or mass lesions in the ventricles. The hydrocephalus that arises in mice infected with T. gondii is considered a consequence of leptomeningeal inflammation that blocks CSF circulation at the subarachnoid space, implying that leptomeningeal inflammation is important in other types of hydrocephalus.

Protein and synthetic polymer injection for induction of obstructive hydrocephalus in rats

Background

The objective of this study was to develop a simple and inexpensive animal model of induced obstructive hydrocephalus with minimal tissue inflammation, as an alternative to kaolin injection.

Materials

Two-hundred and two male Sprague-Dawley rats aged 3 weeks received intracisternal injections of kaolin (25% suspension), Matrigel, type 1 collagen from rat tail, fibrin glue (Tisseel), n-butyl-cyanoacrylate (NBCA), or ethylene vinyl alcohol copolymer (Onyx-18 and Onyx-34). Magnetic resonance imaging was used to assess ventricle size. Animals were euthanized at 2, 5, 10 and 14 days post-injection for histological analysis.

Results

Kaolin was associated with 10% mortality and successful induction of hydrocephalus in 97% of survivors (ventricle area proportion 0.168 ± 0.018). Rapidly hardening agents (fibrin glue, NBCA, vinyl polymer) had high mortality rates and low success rates in survivors. Only Matrigel had relatively low mortality (17%) and moderate success rate (20%). An inflammatory response with macrophages and some lymphocytes was associated with kaolin. There was negligible inflammation associated with Matrigel. A severe inflammatory response with giant cell formation was associated with ethylene vinyl alcohol copolymer.

Conclusion

Kaolin predictably produces moderate to severe hydrocephalus with a mild chronic inflammatory reaction and fibrosis of the leptomeninges. Other synthetic polymers and biopolymers tested are unreliable and cause different types of inflammation.

Expression of TGF-betas and TGF-beta type II receptor in cerebrospinal fluid of patients with idiopathic normal pressure hydrocephalus

We investigated cerebrospinal fluid (CSF) samples from 21 patients with idiopathic normal pressure hydrocephalus (INPH) and 14 controls without neurological disease. The concentrations of leucine-rich alpha-2-glycoprotein (LRG), transforming growth factor (TGF)-beta1, 2, 3 and TGF-beta type II receptor (TbetaR-II) in CSF were measured using ELISA. TGF-beta1, TbetaR-II and LRG CSF levels of patients with INPH were significantly higher than controls, whereas no significant differences in TGF-beta2 levels were found between INPH patients and controls. The present study suggests that TGF-betas expressions may be modulated differently in patients with INPH. These results also indicate that the CSF level assay of TGF-beta1, TbetaR-II and LRG is useful for the diagnosis of patients with INPH, and TGF-beta1, TbetaR-II and LRG may be involved in the pathogenesis of the disease.

Cerebrospinal fluid obstruction and malabsorption in human neonatal hydrocephaly

INTRODUCTION

The pathophysiology involved in human neonatal high-pressure hydrocephalus (HC) includes both cerebrospinal fluid (CSF) malabsorption and obstruction.

OBJECTIVE

The aim was to estimate the relative contribution between CSF malabsorption and obstruction in three different etiological groups of neonatal high-pressure HC by assessment of specific CSF biomarkers indicative of growth factor- and fibrosis-related CSF malabsorption (transforming growth factor beta-1 (TGF beta-1), aminoterminal propeptide of type 1 collagen (PC1NP)].

MATERIALS AND METHODS

Patients were subdivided into three groups. Group A: spina bifida HC (n=12); group B: non-haemorrhagic triventricular HC (n=4); and group C: posthaemorrhagic HC (n=6). To exclude for confounding differences in pro-inflammatory state between the three groups, interleukin-6 (IL-6) CSF concentrations were assessed. Consecutively, the CSF concentrations of TGF beta-1 and PC1NP were compared between the different groups.

RESULTS

Median CSF concentrations of IL-6 were low and did not differ between groups. Median CSF concentrations of PC1NP were significantly lower in group A (median: 180 ng/ml, range 90-808) than in group C (median: 1,060, range 396-1194; p=0.002). TGF beta-1 concentrations were significantly higher in group C (median 355 pg/ml, range 129-843) than in groups A (median 103, range 78-675 pg/ml) and B (median 120 pg/ml, range 91-188; p=0.01 and 0.03, respectively).

CONCLUSIONS

In neonatal posthaemorrhagic HC, high concentrations of malabsorption-related biomarkers contrast with lower concentrations in SB and non-haemorrhagic triventricular HC. During the early development of high pressure HC in SB neonates, CSF biomarkers strongly indicate that CSF obstruction contributes more to the development of HC than malabsorption.

Chronically increased transforming growth factor-beta1 strongly inhibits hippocampal neurogenesis in aged mice

There is increasing evidence that hippocampal learning correlates strongly with neurogenesis in the adult brain. Increases in neurogenesis after brain injury also correlate with improved outcomes. With aging the capacity to generate new neurons decreases dramatically, both under normal conditions and after injury. How this decrease occurs is not fully understood, but we hypothesized that transforming growth factor (TGF)-beta1, a cell cycle regulator that rapidly increases after injury and with age, might play a role. We found that chronic overproduction of TGF-beta1 from astrocytes almost completely blocked the generation of new neurons in aged transgenic mice. Even young adult TGF-beta1 mice had 60% fewer immature, doublecortin-positive, hippocampal neurons than wild-type littermate controls. Bromodeoxyuridine labeling of dividing cells in 2-month-old TGF-beta1 mice confirmed this decrease in neuro-genesis and revealed a similar decrease in astrogenesis. Treatment of early neural progenitor cells with TGF-beta1 inhibited their proliferation. This strongly suggests that TGF-beta1 directly affects these cells before their differentiation into neurons and astrocytes. Together, these data show that TGF-beta1 is a potent inhibitor of hippocampal neural progenitor cell proliferation in adult mice and suggest that it plays a key role in limiting injury and age-related neurogenesis.

Analysis of potential diagnostic biomarkers in cerebrospinal fluid of idiopathic normal pressure hydrocephalus by proteomics

BACKGROUND

The pathogenesis of idiopathic normal pressure hydrocephalus (INPH) is unknown, and the syndrome of INPH remains a diagnostic and therapeutic challenge. The present study investigated the disease-specific proteins that aid in the diagnosis and treatment of INPH and thus to study their role in the disease process.

METHODS

A comparative proteomic analysis was used for clinical screening of cerebrospinal fluid (CSF) proteins in 15 patients with INPH and compared with 12 normal subjects. Furthermore, enzyme linked immunosorbent assay (ELISA) was performed for comparison with CSF proteins between individual INPH patients and controls.

RESULTS

Seven proteins and their isoforms, including leucine-rich alpha-2-glycoprotein (LRG), alpha1-antichymotrypsin, apolipoprotein D, apolipoprotein J, haptoglobin alpha1, serum albumin, and alpha-1-microglobulin/bikunin precursor showed significant changes in CSF of INPH patients compared with controls by proteomic analysis. And significant higher CSF levels of LRG in INPH patients compared with controls were found by ELISA.

CONCLUSIONS

These results indicate that there are significant differences in the expression of certain proteins in the CSF of patients with INPH and normal subjects. In particular, the CSF level assay of LRG suggests that LRG is a specific biomarker for INPH and has potential use in the diagnosis and indication for CSF shunting.

Intraventricular administration of hepatocyte growth factor treats mouse communicating hydrocephalus induced by transforming growth factor beta1

Communicating hydrocephalus may occur spontaneously in elderly patients or occur as a complication of meningitis or intracranial hemorrhage, typically as a result of fibrosis along the route of cerebrospinal fluid (CSF) flow. Hepatocyte growth factor (HGF) has anti-fibrotic properties and is a promising candidate for the treatment of various fibrotic diseases. Thus, the goal of this study was to examine the effect of exogenous HGF (30 microg of human recombinant (hr) HGF intraventricularly for 7 or 14 days) in a model of hr transforming growth factor beta1-induced communicating hydrocephalus in C57BL/6 mice. HGF treatment resulted in a reduction of ventriculomegaly, as demonstrated by magnetic resonance imaging, and improved spatial memory. Further, ink passage test demonstrated improvement of normalized CSF in flow in mice receiving HGF treatment as opposed to delayed CSF flow in the hydrocephalic mice at baseline. Finally, histological examination in hydrocephalic mice undergoing HGF treatment revealed reduction of collagen fibers in the meninges and normalization of their structures. These results indicate that exogenous HGF may be of utility in the treatment of hydrocephalus in humans.

Accumulation of Transforming Growth Factor-β2 and Nitrated Chondroitin Sulfate Proteoglycans in Cerebrospinal Fluid Correlates with Poor Neurologic Outcome in Preterm Hydrocephalus

BACKGROUND

Progressive post-hemorrhagic hydrocephalus in preterm infants strongly predicts abnormal neurologic development, and often accompanies cystic periventricular leukomalacia (cPVL). Transforming growth factor-beta1 (TGF-beta1), associated with hydrocephalus, can upregulate the chondroitin sulfate proteoglycan (CSPG) synthesis. To date, CSPG and their nitrated metabolites (NT-CSPG) have not been evaluated in hydrocephalus.

OBJECTIVES

We hypothesized that TGF-beta1, TGF-beta2, CSPG, and NT-CSPG would accumulate in cerebrospinal fluid (CSF) in preterm hydrocephalus, and their concentrations would correlate with poor long-term outcomes.

METHODS

TGF-beta1, TGF-beta2, CSPG, and NT-CSPG concentrations in CSF were measured prospectively by ELISA in 29 preterm newborns with (n=22) or without (n=34) progressive post-hemorrhagic hydrocephalus, and correlated with progressive neonatal hydrocephalus and neurologic outcome. Only concentrations from each patient's initial CSF sample were used for statistical analysis.

RESULTS

Compared to neonates without hydrocephalus, CSF [TGF-beta1], [TGF-beta2], [CSPG] and [NT-CSPG] were significantly greater by >3-, >35-, >8-, and >3-fold, respectively. Unlike CSF [TGF-beta2] and [CSPG], [TGF-beta1] correlated with CSF [total protein]. Only CSF [NT-CSPG] correlated with cPVL. Unlike [TGF-beta2] or [CSPG], [NT-CSPG] correlation with preterm progressive post-hemorrhagic hydrocephalus (PPHH) was explained entirely by the presence of cPVL among these patients. [TGF-beta2] was >20-fold greater in preterm survivors who required a ventriculoperitoneal shunt for PPHH (n=9), as compared to survivors who did not require a shunt (n=2), or those without hydrocephalus (n=12). [TGF-beta2] and [NT-CSPG] correlated inversely with Bayley Index Scores (15.0 months median adjusted age).

CONCLUSIONS

This is the first report that [TGF-beta2], [CSPG], and [NT-CSPG], measured well before term, accumulate abnormally in preterm progressive post-hemorrhagic hydrocephalus CSF, and correlate with adverse neurologic outcome.

Transforming growth factor-betas in a rat model of neonatal posthaemorrhagic hydrocephalus

Posthaemorrhagic ventricular dilatation (PHVD) is a common complication of intraventricular haemorrhage in premature infants. The aim of this study was to investigate the role of transforming growth factor-betas (TGF-betas), a family of polypeptides with potent desmoplastic properties, in the aetiology of PHVD in a newly developed neonatal rat model of this disorder. Pups were injected with citrated rat blood or artificial cerebrospinal fluid (ACSF) into alternate lateral ventricles on postnatal days 7 and 8. The brains were perfusion-fixed 14 days later and immunohistochemistry was performed for TGF-beta1, -beta2 and -beta3, p44/42 mitogen-activated protein (MAP) kinases, and the extracellular matrix proteins laminin, vitronectin and fibronectin. Ventricular dilatation occurred in 58.3% of animals injected with blood and 36.7% of those injected with ACSF. Periventricular immunoreactivity for TGF-beta1 and -beta2 increased in injected animals irrespective of the presence or absence of ventricular dilatation, although the levels of both isoforms tended to be higher in animals with hydrocephalus. TGF-beta3 immunoreactivity was elevated in hydrocephalic rats only. The immunolabelling for phosphorylated p44/42 MAP kinases rose in a pattern similar to that for TGF-beta1 and -beta2. Expression of TGF-betas was accompanied by deposition of the extracellular matrix proteins fibronectin, laminin and vitronectin. The changes caused by injection of ACSF were the same as those caused by injection of blood. Our results raise the possibility that expression of TGF-betas, together with extracellular matrix protein deposition, may be involved in the development and/or maintenance of hydrocephalus after ventricular distension due to haemorrhage in the neonate.

The Choroid Plexus‐Cerebrospinal Fluid System: From Development to Aging

The function of the cerebrospinal fluid (CSF) and the tissue that secretes it, the choroid plexus (CP), has traditionally been thought of as both providing physical protection to the brain through buoyancy and facilitating the removal of brain metabolites through the bulk drainage of CSF. More recent studies suggest, however, that the CP-CSF system plays a much more active role in the development, homeostasis, and repair of the central nervous system (CNS). The highly specialized choroidal tissue synthesizes trophic and angiogenic factors, chemorepellents, and carrier proteins, and is strategically positioned within the ventricular cavities to supply the CNS with these biologically active substances. Through polarized transport systems and receptor-mediated transcytosis across the choroidal epithelium, the CP, a part of the blood-CSF barrier (BCSFB), controls the entry of nutrients, such as amino acids and nucleosides, and peptide hormones, such as leptin and prolactin, from the periphery into the brain. The CP also plays an important role in the clearance of toxins and drugs. During CNS development, CP-derived growth factors, such as members of the transforming growth factor-beta superfamily and retinoic acid, play an important role in controlling the patterning of neuronal differentiation in various brain regions. In the adult CNS, the CP appears to be critically involved in neuronal repair processes and the restoration of the brain microenvironment after traumatic and ischemic brain injury. Furthermore, recent studies suggest that the CP acts as a nursery for neuronal and astrocytic progenitor cells. The advancement of our knowledge of the neuroprotective capabilities of the CP may therefore facilitate the development of novel therapies for ischemic stroke and traumatic brain injury. In the later stages of life, the CP-CSF axis shows a decline in all aspects of its function, including CSF secretion and protein synthesis, which may in themselves increase the risk for development of late-life diseases, such as normal pressure hydrocephalus and Alzheimer's disease. The understanding of the mechanisms that underlie the dysfunction of the CP-CSF system in the elderly may help discover the treatments needed to reverse the negative effects of aging that lead to global CNS failure.

Analysis of TGF-beta2 and TGF-beta3 expression in the hydrocephalic H-Tx rat brain

INTRODUCTION

Transforming growth factor-beta (TGF-beta) is an important cytokine with modulatory actions in the nervous system. The development of hydrocephalus in mouse models resulting from the overexpression of TGF-beta1 has previously been described, but the mechanism by which this occurs remains obscure.

METHODS

In order to evaluate the role of TGF-beta in hydrocephalus, we used SYBR Green I-based real-time quantitative RT-PCR method and Western blot analysis to analyze the TGF-beta2 and TGF-beta3 mRNA and protein expressions in the cerebral cortex of the H-Tx rat, a model of congenital hydrocephalus.

RESULTS

The hydrocephalic H-Tx rat expressed significantly higher TGF-beta3 levels than their normal siblings (p<0.01) at 7 and 14 days of age. This difference became insignificant when analyzed at 21 days of age. On the other hand, such a difference has not been observed in the TGF-beta2 levels in the hydrocephalic H-Tx rat.

CONCLUSIONS

These results suggest that TGF-beta2 and TGF-beta3 expression may be modulated differently in the hydrocephalus, and TGF-beta3 may contribute to the development of hydrocephalus in this rat model.

The pathogenesis of neonatal post-hemorrhagic hydrocephalus

Hydrocephalus after intraventricular hemorrhage (IVH) has emerged as a major complication of preterm birth and is especially problematic to treat. The hydrocephalus is usually ascribed to fibrosing arachnoiditis, meningeal fibrosis and subependymal gliosis, which impair flow and resorption of cerebrospinal fluid (CSF). Recent experimental studies have suggested that acute parenchymal compression and ischemic damage, and increased parenchymal and perivascular deposition of extracellular matrix proteins--probably due at least partly to upregulation of transforming growth factor-beta (TGF-beta)--are further important contributors to the development of the hydrocephalus. IVH is associated with damage to periventricular white matter and the damage is exacerbated by the development of hydrocephalus; combinations of pressure, distortion, ischaemia, inflammation, and free radical-mediated injury are probably responsible. The damage to white matter accounts for the high frequency of cerebral palsy in this group of infants. The identification of mechanisms and mediators of hydrocephalus and white matter damage is leading to the development of new treatments to prevent permanent hydrocephalus and its neurological complications, and to avoid shunt dependence.

Insights into the pathogenesis of hydrocephalus from transgenic and experimental animal models

Hydrocephalus is a progressive brain disorder characterized by abnormalities in the flow of cerebrospinal fluid (CSF) and ventricular dilatation that leads to cerebral atrophy, and if left untreated, can be fatal. Genetic mutations, congenital malformations, infectious diseases, intracerebral hemorrhages and tumors are common conditions resulting in hydrocephalus. Although the causes of obstructive hydrocephalus are better understood, the mechanisms resulting in chronic, progressive communicating congenital and acquired hydrocephalus are less well understood. In this regard, recent studies in transgenic (tg) mice suggest that increased expression of cytokines such as TGF-beta1 might play an important role by disrupting the vascular extracellular matrix (ECM) remodeling, promoting hemorrhages, and altering the reabsorption of CSF. In this context, the main objective of this manuscript is to provide an overview on the cellular and molecular mechanisms of hydrocephalus based on studies derived from tg and experimental animal models.

Modelling neuroinflammatory phenotypes in vivo

Inflammation of the central nervous system is an important but poorly understood part of neurological disease. After acute brain injury or infection there is a complex inflammatory response that involves activation of microglia and astrocytes and increased production of cytokines, chemokines, acute phase proteins, and complement factors. Antibodies and T lymphocytes may be involved in the response as well. In neurodegenerative disease, where injury is more subtle but consistent, the inflammatory response is continuous. The purpose of this prolonged response is unclear, but it is likely that some of its components are beneficial and others are harmful. Animal models of neurological disease can be used to dissect the specific role of individual mediators of the inflammatory response and assess their potential benefit. To illustrate this approach, we discuss how mutant mice expressing different levels of the cytokine transforming growth factor beta-1 (TGF-beta1), a major modulator of inflammation, produce important neuroinflammatory phenotypes. We then demonstrate how crosses of TGF-beta1 mutant mice with mouse models of Alzheimer's disease (AD) produced important new information on the role of inflammation in AD and on the expression of different neuropathological phenotypes that characterize this disease.

Phase 1 trial of prevention of hydrocephalus after intraventricular hemorrhage in newborn infants by drainage, irrigation, and fibrinolytic therapy

OBJECTIVE

Treatment of posthemorrhagic ventricular dilation in premature infants is fraught with failures and complications. We have piloted a new treatment aimed at removing intraventricular blood and the cytokines associated with hydrocephalus.

METHODS

Twenty-four infants were enrolled with ventricular width enlarged to 4 mm over the 97th centile after a large intraventricular hemorrhage. Sixteen had parenchymal brain lesions before treatment. Median gestation was 28 weeks, and birth weight was 1150 g. At a median postnatal age of 17 days, 2 ventricular catheters (1 right frontal, 1 left occipital) were inserted with 13 infants also having a reservoir frontally. Tissue plasminogen activator 0.5 mg/kg was given intraventricularly 8 hours before the ventricles were irrigated with artificial cerebrospinal fluid at 20 mL/h for a median of 72 hours.

RESULTS

Seventeen of 23 survivors (74%) did not require a ventriculoperitoneal shunt. One infant (of 23 weeks' gestation) died. Two infants developed reservoir-associated infection, and 2 infants had a second intraventricular hemorrhage. Of the 19 survivors aged >12 months postterm, 8 were normal, 7 (37%) had single disability, and 4 (21%) had multiple disabilities.

CONCLUSIONS

Shunt surgery was reduced compared with historical controls with similar treatment criteria. Mortality and single and multiple disability rates all showed downward trends. Reducing pressure, free iron, and proinflammatory and profibrotic cytokines may reduce periventricular brain damage and permanent hydrocephalus. Additional advances will require a controlled trial and better knowledge of the mechanisms of hydrocephalus.

Posthemorrhagic ventricular dilation in the neonate: development and characterization of a rat model

Intraventricular hemorrhage is a common complication of prematurity. Posthemorrhagic ventricular dilation (PHVD) has a high rate of disability and no safe and effective treatment. Its pathogenesis is poorly understood, largely because of the lack of a satisfactory animal model. We have developed a model of neonatal PHVD in the rat. Seven-day-old (P7) Wistar rat pups were given 80-microl injections of citrated rat blood or artificial cerebrospinal fluid (CSF) into alternate lateral ventricles on P7 and P8. Intracranial pressure was monitored and increased briefly by over 8-fold. Some rats received further 10-microl intraventricular injections of India ink on P21. Animals were weighed daily and simple neurologic tests performed. On P21 (or P22 if India ink had been injected), the rats were perfusion-fixed and blocks processed for paraffin histology. Sixty-five percent of pups injected with blood and 50% injected with artificial CSF developed dilated lateral ventricles, with patchy loss of ependyma, marked astrocytic gliosis, and rarefaction of periventricular white matter. India ink injection revealed slow transit of CSF from the dilated lateral ventricles but eventual passage into the subarachnoid space. Pups that had received intraventricular injections but did not develop ventricular dilation nonetheless had lighter brains than littermate controls (p < 0.001). Body weights were not significantly different from controls. Hydrocephalic animals had reduced motor performance as assessed by a grip traction test (p = 0.0002). This model is well suited to studying the pathogenesis of PHVD.

Disturbed spatial learning of rats after intraventricular administration of transforming growth factor-beta 1

Patients with subarachnoid hemorrhage (SAH) who later suffer hydrocephalus show persistently high levels of transforming growth factor-beta 1 (TGF-beta 1) in the cerebrospinal fluid after the onset of SAH. Recombinant TGF-beta 1 induces hydrocephalus in mice. This study examined the spatial learning ability of rats after intraventricular administration of TGF-beta 1. Thirteen-week-old Wistar rats were treated with 0.8 or 8.0 micrograms of human recombinant TGF-beta 1 by direct injection or via osmotic pump. Three months later, their spatial learning ability was evaluated with a Morris water maze. Ventricular size, ultrastructural features, and sodium-potassium-adenosine triphosphatase (Na+, K(+)-ATPase) activity of the subarachnoid space were examined. All three TGF-beta 1-treated groups clearly exhibited impaired spatial learning ability, but they did not exhibit ventricular dilation. Histological examination revealed subarachnoid fibrosis and deactivation of Na+, K(+)-ATPase in the arachnoid cells. These findings are similar to those of our previous experiments involving injection of TGF-beta 1 in mice. The present and previous studies suggest that subarachnoid fibrosis is an important factor in the disturbance of the spatial learning ability of rats, whereas ventricular size is less important.