Reactive gliosis and neuroinflammation in rats with communicating hydrocephalus

Cytotoxic Lesions of the Corpus Callosum Associated with Aneurysmal Subarachnoid Hemorrhage May Influence Shunt-Dependent Chronic Hydrocephalus

BACKGROUND

Cytotoxic lesions of the corpus callosum (CLOCCs) are occasionally associated with aneurysmal subarachnoid hemorrhage (aSAH). The effects of aSAH on clinical outcomes in such cases are unclear. The present study aimed to investigate the frequency and characteristics of CLOCCs associated with aSAH to ascertain the predictors of shunt-dependent chronic hydrocephalus (SDCH) after aSAH.

METHODS

We retrospectively investigated cases of aSAH treated by coil embolization. Patients were divided into those with and without CLOCCs. Between-group differences were evaluated, including clinical outcomes and the characteristics of both the patients and the aneurysms. Patients were divided into those with and without SDCH to identify predictive factors of SDCH after aSAH focusing on CLOCCs.

RESULTS

This single-center study included 196 patients with aSAH. All patients received coil embolization between April 2013 and March 2020. CLOCCs were detected in 38 (19.4%) patients. In the group with CLOCCs, male sex, poor severity grade at onset, acute hydrocephalus, SDCH (all P < 0.01), and Fisher group 3 or 4 (P = 0.04) were significantly more common than in the group without CLOCCs. Diabetes and CLOCCs were significant predictors of SDCH after aSAH in multivariate analysis (diabetes: P < 0.01, odds ratio: 6.73, 95% confidence interval: 1.61-28.09; CLOCCs: P < 0.01, odds ratio: 6.86, 95% confidence interval: 2.87-16.38).

CONCLUSIONS

CLOCCs and SDCH were common in patients with poor-grade aSAH, and CLOCCs were independent predictors of SDCH after aSAH. Meticulous follow-up is necessary to detect SDCH after aSAH, especially in patients with poor-grade aSAH and CLOCCs.

Noradrenergic Pathways Involved in Micturition in an Animal Model of Hydrocephalus-Implications for Urinary Dysfunction

Hydrocephalus is characterized by enlargement of the cerebral ventricles, accompanied by distortion of the periventricular tissue. Patients with hydrocephalus usually experience urinary impairments. Although the underlying etiology is not fully described, the effects of hydrocephalus in the neuronal network responsible for the control of urination, which involves periventricular areas, including the periaqueductal gray (PAG) and the noradrenergic locus coeruleus (LC). In this study, we aimed to investigate the mechanisms behind urinary dysfunction in rats with kaolin-induced hydrocephalus. For that purpose, we used a validated model of hydrocephalus-the rat injected with kaolin in the cisterna magna-also presents urinary impairments in order to investigate the putative involvement of noradrenergic control from the brain to the spinal cord Onuf's nucleus, a key area in the motor control of micturition. We first evaluated bladder contraction capacity using cystometry. Since our previous characterization of the LC in hydrocephalic animals showed increased levels of noradrenaline, we then evaluated the noradrenergic innervation of the spinal cord's Onuf's nucleus by measuring levels of dopamine β-hydroxylase (DBH). We also evaluated the expression of the c-Fos protooncogene, the most widely used marker of neuronal activation, in the ventrolateral PAG (vlPAG), an area that plays a major role in the control of urination by its indirect control of the LC via pontine micturition center. Hydrocephalic rats showed an increased frequency of bladder contractions and lower minimum pressure. These animals also presented increased DBH levels at the Onuf´s nucleus, along with decreased c-Fos expression in the vlPAG. The present findings suggest that impairments in urinary function during hydrocephalus may be due to alterations in descending noradrenergic modulation. We propose that the effects of hydrocephalus in the decrease of vlPAG neuronal activation lead to a decrease in the control over the LC. The increased availability of noradrenaline production at the LC probably causes an exaggerated micturition reflex due to the increased innervation of the Onuf´s nucleus, accounting for the urinary impairments detected in hydrocephalic animals. The results of the study provide new insights into the neuronal underlying mechanisms of urinary dysfunction in hydrocephalus. Further research is needed to fully evaluate the translational perspectives of the current findings.

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.

Liver transplantation in rare late-onset ornithine transcarbamylase deficiency with central nervous system injury: A case report and review of the literature

BACKGROUND

Ornithine transcarbamylase deficiency (OTCD) is a genetic metabolic disease. Its clinical manifestations are mainly central nervous system dysfunction caused by high blood ammonia. Late-onset OTCD combined with central nervous system injury has a poor therapeutic response, which is one of the main factors affecting the prognosis and quality of life of patients. liver transplantation (LT) has gradually become a radical treatment for OTCD, which has achieved good results. However, there is no consensus on the timing of LT and problems of nervous system damage and repair.

METHODS

We report the development of late-onset OTCD with central nervous system injury in an 11-year-old child who received liver transplantation at our transplant center. His first symptoms were nonprojectile vomiting, followed by irritability and disturbance of consciousness, after which the disease progressed rapidly and finally resulted in a coma. After liver transplantation, the child's consciousness returned to normal, muscle strength of the limbs gradually recovered from grade 0 to grade 4, and muscle tone gradually recovered from grade 4 to grade 1, suggesting that the motor nerves had gradually recovered. However, the child is currently mentally retarded, and the language center has not yet fully recovered.At the same time, we made a literature review of OTCD.

CONCLUSION

For OTCD patients with central nervous system injury, liver transplantation can fundamentally solve the problem of ammonia metabolism in the liver and avoids further damage to the central nervous system caused by hyperammonemia. At the same time, children's nervous systems are in the developmental stage when neuroplasticity is greatest. If liver transplantation is performed as soon as possible, nerve repair is still possible.

Novel therapeutic modulators of astrocytes for hydrocephalus

Hydrocephalus is mainly characterized by excessive production or impaired absorption of cerebrospinal fluid that causes ventricular dilation and intracranial hypertension. Astrocytes are the key response cells to inflammation in the central nervous system. In hydrocephalus, astrocytes are activated and show dual characteristics depending on the period of development of the disease. They can suppress the disease in the early stage and may aggravate it in the late stage. More evidence suggests that therapeutics targeting astrocytes may be promising for hydrocephalus. In this review, based on previous studies, we summarize different forms of hydrocephalus-induced astrocyte reactivity and the corresponding function of these responses in hydrocephalus. We also discuss the therapeutic effects of astrocyte regulation on hydrocephalus in experimental studies.

Reactive microglia and mitochondrial unfolded protein response following ventriculomegaly and behavior defects in kaolin-induced hydrocephalus

Ventriculomegaly induced by the abnormal accumulation of cerebrospinal fluid (CSF) leads to hydrocephalus, which is accompanied by neuroinflammation and mitochondrial oxidative stress. The mitochondrial stress activates mitochondrial unfolded protein response (UPRmt), which is essential for mitochondrial protein homeostasis. However, the association of inflammatory response and UPRmt in the pathogenesis of hydrocephalus is still unclear. To assess their relevance in the pathogenesis of hydrocephalus, we established a kaolin-induced hydrocephalus model in 8-week-old male C57BL/6J mice and evaluated it over time. We found that kaolin-injected mice showed prominent ventricular dilation, motor behavior defects at the 3-day, followed by the activation of microglia and UPRmt in the motor cortex at the 5-day. In addition, PARP-1/NF-κB signaling and apoptotic cell death appeared at the 5-day. Taken together, our findings demonstrate that activation of microglia and UPRmt occurs after hydrocephalic ventricular expansion and behavioral abnormal-ities which could be lead to apoptotic neuronal cell death, providing a new perspective on the pathogenic mechanism of hydrocephalus.

Pain Modulation from the Locus Coeruleus in a Model of Hydrocephalus: Searching for Oxidative Stress-Induced Noradrenergic Neuroprotection

Pain transmission at the spinal cord is modulated by noradrenaline (NA)-mediated actions that arise from supraspinal areas. We studied the locus coeruleus (LC) to evaluate the expression of the cathecolamine-synthetizing enzyme tyrosine hydroxylase (TH) and search for local oxidative stress and possible consequences in descending pain modulation in a model of hydrocephalus, a disease characterized by enlargement of the cerebral ventricular system usually due to the obstruction of cerebrospinal fluid flow. Four weeks after kaolin injection into the cisterna magna, immunodetection of the catecholamine-synthetizing enzymes TH and dopamine-β-hydroxylase (DBH) was performed in the LC and spinal cord. Colocalization of the oxidative stress marker 8-OHdG (8-hydroxyguanosine; 8-OHdG), with TH in the LC was performed. Formalin was injected in the hindpaw both for behavioral nociceptive evaluation and the immunodetection of Fos expression in the spinal cord. Hydrocephalic rats presented with a higher expression of TH at the LC, of TH and DBH at the spinal dorsal horn along with decreased nociceptive behavioral responses in the second (inflammatory) phase of the formalin test, and formalin-evoked Fos expression at the spinal dorsal horn. The expression of 8-OHdG was increased in the LC neurons, with higher co-localization in TH-immunoreactive neurons. Collectively, the results indicate increased noradrenergic expression at the LC during hydrocephalus. The strong oxidative stress damage at the LC neurons may lead to local neuroprotective-mediated increases in NA levels. The increased expression of catecholamine-synthetizing enzymes along with the decreased nociception-induced neuronal activation of dorsal horn neurons and behavioral pain signs may indicate that hydrocephalus is associated with alterations in descending pain modulation.

C3/C3aR inhibition alleviates GMH-IVH-induced hydrocephalus by preventing microglia-astrocyte interactions in neonatal rats

Activation of microglia and astrocytes following germinal matrix hemorrhage and intraventricular hemorrhage (GMH-IVH) plays a detrimental role in posthemorrhagic hydrocephalus (PHH). It is still unclear whether or how an interaction occurs between microglia and astrocytes in PHH. Here, we investigated the role of the C3/C3aR pathway in microglia and astrocyte interactions and whether C3/C3aR-targeted inhibition could alleviate PHH following GMH-IVH. A total of 152 Sprague-Dawley rats at postnatal day seven (P7) were enrolled in the study, and collagenase VII was used to induce GMH-IVH. Minocycline (45 mg/kg) was administered to inhibit microglial activation. Complement C3a peptide and C3aR antagonist (SB 290157, 10 mg/kg) were used to regulate the C3/C3aR pathway. As a result, the data demonstrated that periventricular C3aR⁺/Iba-1⁺ microglia and C3⁺/GFAP⁺ astrocytes were significantly increased in GMH-IVH pups at 28 days after surgery. Intranasal C3a peptide upregulated C3aR expression in microglia. Inhibition of microglia by minocycline decreased both C3⁺/GFAP⁺ astrocytes and the colocalization volume of Iba-1 and GFAP. In addition, intraperitoneally injected C3aRA alleviated the periventricular colocalization volume of microglia and astrocytes. Compared with vehicle-treated pups, the protein level of IL-1β, IL-6 and TNF-α in cerebral spinal fluid and brain tissue at 28 days following GMH-IVH were reduced in C3aRA-treated pups. Moreover, hydrocephalus was alleviated, and long-term cognitive ability were improved in the C3aRA-treated group. Our data presented simultaneous periventricular astrogliosis and microgliosis of pups following GMH-IVH and proved their potential interaction through the C3/C3aR pathway, indicating C3aRA as a potential pharmacological treatment of PHH in neonates.

Decadron, Diamox, and Zantac: A Novel Combination for Ventricular Shunt Failure in Pediatric Neurosurgical Patients

OBJECTIVE

Cerebral ventricular shunt failure is common and presents with symptoms that range from headaches to death. The combination of Diamox (acetazolamide), Decadron (dexamethasone), and Zantac (ranitidine) (DDZ) is used at our institution to medically stabilize pediatric patients presenting with symptomatic shunt failure before shunt revision. We describe our experience of this drug combination as a temporizing measure to decrease symptoms associated with shunt failure.

METHODS

We performed a single-center retrospective chart review of patients younger than 18 years with ventricular shunt failure who underwent a shunt revision between January 2015 to October 2017 and received DDZ before surgery. The outcome variables evaluated included pre-DDZ and post-DDZ clinical symptoms, pain scores, and vital signs.

RESULTS

There were 112 cases that received DDZ before shunt revision. The 4 most commonly reported symptoms were analyzed. Headache was observed in 42 cases pre-DDZ, and post-DDZ there was a 71% reduction in headache (P < 0.0001); emesis was reported pre-DDZ in 76 cases, and post-DDZ there was an 83% reduction (P < 0.0001); irritability was noted pre-DDZ in 30 cases, and post-DDZ there was a 77% reduction (P = 0.0003); lethargy pre-DDZ was observed in 60 cases, and post-DDZ 73% demonstrated improvement (P < 0.0001). Maximum pain scores significantly decreased post-DDZ (P < 0.0001). Heart rate, systolic, and diastolic blood pressures significantly decreased post-DDZ (P < 0.0001, P < 0.0001, P = 0.0002, respectively).

CONCLUSIONS

The combination of Decadron, Diamox, and Zantac is a novel treatment for ventricular shunt failure that may temporarily improve symptoms in patients awaiting shunt revision. Future studies could compare efficacy with other medical treatments.

Inhibition of neuronal necroptosis mediated by RIP1/RIP3/MLKL provides neuroprotective effects on kaolin-induced hydrocephalus in mice

OBJECTIVES

Necroptosis is widespread in neurodegenerative diseases. Here, we examined necroptosis in the hippocampus and cortex after hydrocephalus and found that a necroptosis pathway inhibitor alleviates necroptosis and provides neuroprotective effects.

MATERIALS AND METHODS

Hydrocephalus was induced in C57BL/6 mice by kaolin. Haematoxylin and eosin (HE), Nissl, PI and Fluoro-Jade B (FJB) staining were used for general observations. Phosphorylated receptor-interacting protein kinase 3 (p-RIP3) and phosphorylated mixed lineage kinase domain-like (p-MLKL) were measured by Western blotting and immunohistochemistry. Scanning electron microscopy (SEM) was used to observe ependymal cilia. Magnetic resonance imaging (MRI) and the Morris water maze (MWM) test were used to assess neurobehavioral changes. Immunofluorescence was used to detect microglial and astrocyte activation. Inflammatory cytokines were measured by Western blotting and RT-PCR.

RESULTS

Obvious pathological changes appeared in the hippocampus and cortex after hydrocephalus, and expression of the necroptosis markers p-RIP3, p-MLKL and inflammatory cytokines increased. Necrostatin-1 (Nec-1) and GSK872 reduced necrotic cell death, attenuated p-RIP3 and p-MLKL levels, slightly improved neurobehaviours and inhibited microglial and astrocyte activation and inflammation.

CONCLUSIONS

RIP1/RIP3/MLKL mediates necroptosis in the cortex and hippocampus in a hydrocephalus mouse model, and Nec-1 and GSK872 have some neuroprotective effects.

Novel therapeutics for hydrocephalus: Insights from animal models

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

Elevated Neuroglobin Lessens Neuroinflammation and Alleviates Neurobehavioral Deficits Induced by Acute Inhalation of Combustion Smoke in the Mouse

Acute inhalation of combustion smoke produces long-term neurologic deficits in survivors. To study the mechanisms that contribute to the development of neurologic deficits and identify targets for prevention, we developed a mouse model of acute inhalation of combustion smoke, which supports longitudinal investigation of mechanisms that underlie the smoke induced inimical sequelae in the brain. Using a transgenic mouse engineered to overexpress neuroglobin, a neuroprotective oxygen-binding globin protein, we previously demonstrated that elevated neuroglobin preserves mitochondrial respiration and attenuates formation of oxidative DNA damage in the mouse brain after smoke exposure. In the current study, we show that elevated neuronal neuroglobin attenuates the persistent inflammatory changes induced by smoke exposure in the mouse brain and mitigates concordant smoke-induced long-term neurobehavioral deficits. Specifically, we found that increases in hippocampal density of GFAP and Iba-1 positive cells that are detected post-smoke in wild-type mice are absent in the neuroglobin overexpressing transgenic (Ngb-tg) mice. Similarly, the smoke induced hippocampal myelin depletion is not observed in the Ngb-tg mice. Importantly, elevated neuroglobin alleviates behavioral and memory deficits that develop after acute smoke inhalation in the wild-type mice. Taken together, our findings suggest that the protective effects exerted by neuroglobin in the brains of smoke exposed mice afford protection from long-term neurologic sequelae of acute inhalation of combustion smoke. Our transgenic mouse provides a tool for assessing the potential of elevated neuroglobin as possible strategy for management of smoke inhalation injury.

Acute inhalation of combustion smoke triggers neuroinflammation and persistent anxiety-like behavior in the mouse

CONTEXT

Acute inhalation of combustion smoke triggers neurologic sequelae in survivors. Due to the challenges posed by heterogeneity of smoke exposures in humans, mechanistic links between acute smoke inhalation and neuropathologic sequelae have not been systematically investigated.

METHODS

Here, using mouse model of acute inhalation of combustion smoke, we studied longitudinal neurobehavioral manifestations of smoke exposures and molecular/cellular changes in the mouse brain.

RESULTS

Immunohistochemical analyses at eight months post-smoke, revealed hippocampal astrogliosis and microgliosis accompanied by reduced myelination. Elevated expression of proinflammatory cytokines was also detected. Longitudinal testing in different neurobehavioral paradigms in the course of post-smoke recovery, revealed lasting anxiety-like behavior. The examined paradigms included the open field exploration/anxiety testing at two, four and six months post-smoke, which detected decreases in total distance traveled and time spent in the central arena in the smoke-exposed compared to sham-control mice, suggestive of dampened exploratory activity and increased anxiety-like behavior. In agreement with reduced open field activity, cued fear conditioning test revealed increased freezing in response to conditioned auditory stimulus in mice after acute smoke inhalation. Similarly, elevated plus maze testing demonstrated lesser presence in open arms of the maze, consistent with anxiety-like behavior, for the post-smoke exposure mice.

CONCLUSIONS

Taken together, our data demonstrate for the first time persistent neurobehavioral manifestations of acute inhalation of combustion smoke and provide new insights into long-term progression of events initiated by disrupted brain oxygenation that might contribute to lasting adverse sequelae in survivors of smoke inhalation injuries.

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.

Shunt-dependent hydrocephalus after aneurysmal subarachnoid hemorrhage: the role of intrathecal interleukin-6

OBJECT

Aneurysmal subarachnoid hemorrhage (SAH) has been reported to induce an intrathecal inflammatory reaction reflected by cytokine release, particularly interleukin-6 (IL-6), which correlates with early brain damage and poor outcome. The present study examines intrathecal IL-6 production together with clinical parameters, as a predictor of posthemorrhagic shunt dependency.

METHODS

Among 186 SAH patients admitted between July 2010 and December 2012, 82 received external ventricular drainage due to acute hydrocephalus. In these patients, cerebrospinal fluid (CSF) concentrations of IL-6 were measured within the first 14 days after SAH. Patients whose IL-6 values were not determined regularly and those who did not survive until discharge were excluded. The peak value of IL-6, ventricular infection during the hospital stay, microbial CSF culture, patient's age and sex, Hunt and Hess grade, and aneurysm location were assumed as predictive for shunt dependency.

RESULTS

Sixty-nine patients were included, 24 of whom underwent shunt surgery. Peak IL-6 values of ≥10,000 pg/ml were significantly associated with a higher incidence of shunt dependency (p = 0.009). Additional risk factors were aneurysm location on the anterior cerebral artery and its branches or in the posterior circulation (p = 0.025), and age ≥60 years (p = 0.014). In a multivariate analysis, IL-6 ≥10,000 pg/ml appeared to be the only independent predictor for shunt dependency (p = 0.029) CONCLUSION: CSF IL-6 values of ≥10,000 pg/ml in the early post-SAH period may be a useful diagnostic tool for predicting shunt dependency in patients with acute posthemorrhagic hydrocephalus. The development of shunt-dependent posthemorrhagic hydrocephalus remains a multifactorial process.

Inhibition of Wnt/β-catenin signal is alleviated reactive gliosis in rats with hydrocephalus

BACKGROUND

Reactive gliosis has been implicated in the pathogenesis of communicating hydrocephalus. Because the activation of Wnt/β-catenin signaling pathway is considered as a significant factor to contribute to brain development, neurodegenerative process, and reactive gliosis, we target this pathway for intervention by using sFRP-l and investigated the expression of β-catenin, cyclin D-1, and glial fibrillary acidic protein (GFAP) in the brain of experimental hydrocephalic rats in terms of protein and gene expression.

METHODS

Therefore, 30 adult SD rats were randomly divided into the normal group (n = 5), the sham operation group (n = 5), the hydrocephalus group (n = 10), and the sFRP-l group (n = 10). Hydrocephalic rat models were induced by intraventricular injections of 3% kaolin while sFRP-l group was treated by sFRP-l with kaolin injections. The ventricular dilatation was examinated by MRI at 2-week post-operation. After that, β-catenin, cyclin D-1, and GFAP were qualified by Western blot and immunohistochemistry.

RESULTS

According to the result, the expression of β-catenin and cyclin D-1 increased (P < 0. 05) in the brain tissue of the hydrocephalus group compared with that of the sham group, while GFAP expression in the hydrocephalus group is more obvious (P < 0. 05). In the sFRP-l group, the expression of β-catenin and cyclin D-1 and GFAP expression is lower (P < 0. 05) compared with those of the hydrocephalus group. We demonstrated that the Wnt/β-catenin pathway is activated in the experimental hydrocephalic rat brain. sFRP-l inhibited the expression of β-catenin and cyclin D-1 and alleviated reactive gliosis in the hydrocephalic rat brain tissue, while the development of hydrocephalus was delayed.

CONCLUSION

These results suggest that regulating Wnt/β-catenin signaling pathway may provide new therapeutic methods for hydrocephalic patients.

Associations between in vivo neuroimaging and postmortem brain cytokine markers in a rodent model of Wernicke's encephalopathy

Thiamine (vitamin B1) deficiency, associated with a variety of conditions, including chronic alcoholism and bariatric surgery for morbid obesity, can result in the neurological disorder Wernicke's encephalopathy (WE). Recent work building upon early observations in animal models of thiamine deficiency has demonstrated an inflammatory component to the neuropathology observed in thiamine deficiency. The present, multilevel study including in vivo magnetic resonance imaging (MRI) and spectroscopy (MRS) and postmortem quantification of chemokine and cytokine proteins sought to determine whether a combination of these in vivo neuroimaging tools could be used to characterize an in vivo MR signature for neuroinflammation. Thiamine deficiency for 12days was used to model neuroinflammation; glucose loading in thiamine deficiency was used to accelerate neurodegeneration. Among 38 animals with regional brain tissue assayed postmortem for cytokine/chemokine protein levels, three groups of rats (controls+glucose, n=6; pyrithiamine+saline, n=5; pyrithiamine+glucose, n=13) underwent MRI/MRS at baseline (time 1), after 12days of treatment (time 2), and 3h after challenge (glucose or saline, time 3). In the thalamus of glucose-challenged, thiamine deficient animals, correlations between in vivo measures of pathology (lower levels of N-acetyle aspartate and higher levels of lactate) and postmortem levels of monocyte chemotactic protein-1 (MCP-1, also known as chemokine ligand 2, CCL2) support a role for this chemokine in thiamine deficiency-related neurodegeneration, but do not provide a unique in vivo signature for neuroinflammation.

Morinda citrifolia L. (noni) and memantine attenuate periventricular tissue injury of the fourth ventricle in hydrocephalic rabbits

This study was designed to evaluate the neuroprotective effects of Morinda citrifolia L. (Rubiaceae), commonly known as noni, and memantine (a N-methy-D-aspartate receptor inhibitor) on hydrocephalus-induced neurodegenerative disorders. Kaolin was injected into the cistern magna of male adult New Zealand rabbits to establish a hydrocephalus animal model. Memantine (20 mg/kg, intraperitoneally; memantine-treated group) or noni (5 mL/kg, intragastrically; noni-treated group) was administered daily for 2 weeks. Microtubule-associated protein-2 and caspase-3 immunohistochemistry were performed to detect neuronal degeneration and apoptosis in the periventricular tissue of the fourth ventricle of rabbits. Microtubule-associated protein-2 staining density was significantly decreased in the hydrocephalic group, while the staining density was significantly increased in the memantine- and noni-treated groups, especially in the noni-treated group. Noni treatment decreased the number of caspase-3-positive cells in rabbits with hydrocephalus, while memantine had no effect. These findings suggest that noni exhibits more obvious inhibitory effects on hydrocephalus-induced neurodegenerative disorders than memantine in periventricular tissue of the fourth ventricle.

Strain-dependent brain defects in mouse models of primary ciliary dyskinesia with mutations in Pcdp1 and Spef2

Hydrocephalus is caused by the accumulation of cerebrospinal fluid (CSF) in the cerebral ventricular system which results in an enlargement of the cranium due to increased intraventricular pressure. The increase in pressure within the brain typically results in sloughing of ciliated ependymal cells, loss of cortical gray matter, and increased gliosis. Congenital hydrocephalus is associated with several syndromes including primary ciliary dyskinesia (PCD), a rare, genetically heterogeneous, pediatric syndrome that results from defects in motile cilia and flagella. We have examined the morphological and physiological defects in the brains of two mouse models of PCD, nm1054 and bgh, which have mutations in Pcdp1 (also known as Cfap221) and Spef2, respectively. Histopathological and immunohistochemical analyses of mice with these mutations on the C57BL/6J and 129S6/SvEvTac genetic backgrounds demonstrate strain-dependent morphological brain damage. Alterations in astrocytosis, microglial activation, myelination, and the neuronal population were identified and are generally more severe on the C57BL/6J background. Analysis of ependymal ciliary clearance ex vivo and CSF flow in vivo demonstrate a physiological defect in nm1054 and bgh mice on both genetic backgrounds, indicating that abnormal cilia-driven flow is not the sole determinant of the severity of hydrocephalus in these models. These results suggest that genetic modifiers play an important role in susceptibility to severe PCD-associated hydrocephalus.

Antisecretory factor (AF) exerts no effects on intracranial pressure (ICP) waves and ICP in patients with idiopathic normal pressure hydrocephalus and idiopathic intracranial hypertension

BACKGROUND

Antisecretory factor (AF) and derivates thereof counteract brain edema and inflammation, and normalize ICP dynamics. The aim of the present study was to assess whether AF normalized the abnormal ICP waves, indicative of impaired intracranial compliance, seen in patients with idiopathic normal pressure hydrocephalus (iNPH) and idiopathic intracranial hypertension (IIH). The hypothesis was that brain swelling contributes to the abnormal ICP waves.

METHODS

The study enrolled patients undergoing diagnostic ICP wave monitoring for either iNPH or IIH. The ICP waves and ICP were recorded continuously before and after oral administration of Salovum® (0.5 g/kg body weight/day divided by three doses), a freeze-dried egg yolk enriched in AF activity. Mean ICP wave amplitude (MWA), mean ICP wave rise time coefficient (MWRTC), and mean ICP were compared before and after Salovum® administration.

RESULTS

A total of 10 iNPH patients and 8 IIH patients were included. No significant changes in the ICP wave indices or ICP were seen after Salovum® administration. Neither any significant time-dependent effect was observed.

CONCLUSION

The lack of effect of Salovum® on ICP wave indices and ICP in iNPH and IIH may provide indirect evidence that brain swelling does not play a crucial role in the ICP wave indices or ICP of these conditions.

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.

LPS induces mediators of neuroinflammation, cell proliferation, and GFAP expression in human astrocytoma cells U373MG: the anti-inflammatory and anti-proliferative effect of guggulipid

Neuroinflammation has been considered to be an integrated part of human neurodegenerative diseases. In this study, we examined the effect of guggulipid on cell proliferation, nitrite release, interleukin IL-6 and IL-1 beta release, and expression of COX-2 and glial fibrillary acidic protein (GFAP) in LPS-stimulated U373MG cells. LPS significantly stimulated human astrocytoma cells U373MG by up-regulating these neuroinflammatory mediators. Guggulipid alone had no effect on the cell proliferation of U373MG cells. The up regulation in nitrite release, cell proliferation, and release of IL-6 and IL-1 beta in LPS stimulated human astrocytoma cells were dose-dependently inhibited by co-treatment with guggulipid. The expression level of COX-2 and GFAP proteins was up regulated by LPS but the increased level of COX-2 and GFAP was significantly down regulated by treatment with guggulipid. These data indicate that guggulipid has a modulatory effect on all these parameters, which might explain its beneficial effect in the treatment of neuroinflammation-associated disorders directly relating to human aspects.

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.

Expression of HGF, MMP-9 and TGF-β1 in the CSF and cerebral tissue of adult rats with hydrocephalus

OBJECT

The hepatocyte growth factor (HGF), matrix metallopeptidase-9 (MMP-9) and transforming growth factor-β1 (TGF-β1) are important cytokines with modulatory actions in the nervous system. In this study, we attempted to investigate the role and expression of HGF, MMP-9 and TGF-β1 in the cerebral tissue and cerebrospinal fluid (CSF) of adult rats with hydrocephalus induced via intraventricular kaolin injection.

METHODS

Adult male Sprague-Dawley rats were randomly divided into two groups: control group (n = 12) and experimental group (n = 20). Kaolin was injected into the lateral ventricle of experimental animals. Control rats underwent the same procedure but received sterile saline injection instead of kaolin. Magnetic resonance imaging was used to assess ventricle size. The CSF was studied by enzyme-linked immunosorbent assay and the excised brains were studied by reverse-transcription polymerase chain reaction and immunohistochemical analyses to measure the messenger RNA and protein expression level of HGF, MMP-9 and TGF-β1.

RESULTS

Hydrocephalus was induced in all the rats after kaolin injection into the lateral ventricle. After 2 weeks, the expressions of HGF, MMP-9 and TGF-β1 in the CSF and cerebral tissue were significantly increased in the experimental group compared with the control group.

CONCLUSIONS

This results indicated that HGF, MMP-9 and TGF-β1 may participate in the formation and prognosis of hydrocephalus after kaolin induction.

Minocycline reduces reactive gliosis in the rat model of hydrocephalus

Background

Reactive gliosis had been implicated in injury and recovery patterns associated with hydrocephalus. Our aim is to determine the efficacy of minocycline, an antibiotic known for its anti-inflammatory properties, to reduce reactive gliosis and inhibit the development of hydrocephalus.

Results

The ventricular dilatation were evaluated by MRI at 1-week post drugs treated, while GFAP and Iba-1were detected by RT-PCR, Immunohistochemistry and Western blot. The expression of GFAP and Iba-1 was significantly higher in hydrocephalic group compared with saline control group (p < 0.05). Minocycline treatment of hydrocephalic animals reduced the expression of GFAP and Iba-1 significantly (p < 0.05). Likewise, the severity of ventricular dilatation is lower in minocycline treated hydrocephalic animals compared with the no minocycline group (p < 0.05).

Conclusion

Minocycline treatment is effective in reducing the gliosis and delaying the development of hydrocephalus with prospective to be the auxiliary therapeutic method of hydrocephalus.