Glial Cell Damage Research Articles

Titanium dioxide nanoparticles induce the expression of early and late receptors for adhesion molecules on monocytes.

BackgroundThere is growing evidence that exposure to titanium dioxide nanoparticles (TiO2 NPs) could be harmful. Previously, we have shown that TiO2 NPs induces endothelial cell dysfunction and damage in glial cells. Considering that inhaled particles can induce systemic effects and the evidence that nanoparticles may translocate out of the lungs, we evaluated whether different types of TiO2 NPs can induce the expression of receptors for adhesion molecules on monocytes (U937 cell line). We evaluated the role of reactive oxygen spices (ROS) on these effects.MethodsThe expression of receptors for early (sLex and PSGL-1) and late (LFA-1, VLA-4 and αVβ3) adhesion molecules was evaluated in U937 cells on a time course (3–24 h) using a wide range of concentrations (0.001-100 μg/mL) of three types of TiO2 NPs (<25 nm anatase, 50 nm anatase-rutile or < 100 nm anatase). Cells exposed to TNFα were considered positive controls, and unexposed cells, negative controls. In some experiments we added 10 μmolar of N-acetylcysteine (NAC) to evaluate the role of ROS.ResultsAll tested particles, starting at a concentration of 0.03 μg/mL, induced the expression of receptors for early and late adhesion molecules. The largest increases were induced by the different molecules after 3 h of exposure for sLex and PSGL-1 (up to 3-fold of the positive controls) and after 18 h of exposure for LFA-1, VLA-4 and αVβ3 (up to 2.5-fold of the positive controls). Oxidative stress was observed as early as 10 min after exposure, but the maximum peak was found after 4 h of exposure. Adhesion of exposed or unexposed monocytes to unexposed or exposed endothelial cells was tested, and we observed that monocytes cells adhere in similar amounts to endothelial cells if one of the two cell types, or both were exposed. When NAC was added, the expression of the receptors was inhibited.ConclusionsThese results show that small concentrations of particles may activate monocytes that attach to endothelial cells. These results suggest that distal effects can be induced by small amounts of particles that may translocate from the lungs. ROS play a central role in the induction of the expression of these receptors.Electronic supplementary materialThe online version of this article (doi:10.1186/s12989-016-0147-3) contains supplementary material, which is available to authorized users.

Effect of homocysteine on survival of human glial cells.

Several neurodegenerative conditions, such as Alzheimer's disease and Parkinson's disease, or vascular dementia and cognitive impairment, are associated with mild hyperhomocysteinemia. Hyperhomocysteinemia is defined as an increase of the homocysteine (Hcy) level beyond 10 microM. Although the adverse effect of Hcy on neurons is well documented, knowledge about the impact of this amino acid on glial cells is missing. Therefore, with the aim to evaluate the neurotoxic properties of Hcy on glial cells, we used a glioblastoma cell line as a study model. The viability of cells was assayed biochemically and cytologically. At a concentration around 50 microM in the culture medium D,L-Hcy induced cell death. It is noteworthy that Hcy induces cell death of human glial cells at concentrations encountered during mild hyperhomocysteinemia. Therefore, we propose that Hcy-induced impairment of neuronal functions along with damage of glial cells may contribute to the etiopathogenesis of neurodegenerative diseases associated with hyperhomocysteinemia.

The response of neurons and glial cells of crayfish to photodynamic treatment: Transcription factors and epigenetic regulation

Photodynamic therapy (PDT) based on photoproduction of highly toxic singlet oxygen, which causes oxidative stress and death of stained cells, is used for treatment of cancer including that of brain tumors. The study of signaling and epigenetic mechanisms of photodynamic damage of normal neurons and glial cells was carried out on isolated crayfish mechanoreceptors consisting of single sensory neurons enveloped by glial cells. PDT effect caused necrosis of neurons and glial cells and apoptosis of glial cells. Application of specific inhibitors or activators of transcription factors: NF-?B (betulinic acid, parthenolide, CAPE), AP-1 (SR11302), STAT-3 (cucurbitacin, stattic), HIF-1 (KG-548, FM19G11, DMOG), and p53 (RITA, WR1065, nutlin-3, pifithrin-a) or those of epigenetic processes, such as DNA methylation (5-azacytidine, decitabine) or histone deacetylation (sodium valproate, trichostatin A, SBHA) demonstrated that PDTinduced death of neurons and glial cells is regulated by transcription factors and epigenetic regulators. Epigenetic processes did not influence PDT-induced necrosis of neurons. Among the transcription factors studied, only STAT-3 was involved in PDT-induced necrosis of neurons. DNA methylation and histone deacetylation, which suppress transcription, mediated PDT-induced necrosis of glial cells. The transcription factor NF-?B had antinecrotic effects on glia. All transcription factors studied and histone deacetylase were involved in apoptosis of glial cells. Their modulators might serve as potential gliaand neuroprotective agents.

Cerebrospinal fluid biomarkers in facial nerve palsy caused by Varicella Zoster virus

No: 1680 Presentation at ESCV 2015: Poster 1 Cerebrospinal fluid biomarkers in facial nerve palsy caused by Varicella Zoster virus J. Lindstrom1,∗, A. Grahn1, H. Zetterberg2, M. Studahl1 1 Department of Infectious Diseases, Sahlgrenska University Hospital, Ostra, Goteborg, Sweden 2 Clinical Neurochemistry Laboratory, Institute of Neuroscience and Physiology, Department of Psychiatry and Neurochemistry, Sweden Background: Reactivation of Varicella Zoster virus (VZV) can cause facial nerve palsy with neurological sequels despite treatment with aciclovir and/or corticosteroids. Associated symptoms such as vertigo and loss of hearing are frequent. Facial nerve palsy caused by VZV manifest as Ramsay Hunt syndrome when blisters are present, or as zoster sine herpete without blisters. Neurofilament light protein (NFL), glial fibrillary acidic protein (GFAp) and S-100 are cerebrospinal fluid (CSF) biomarkers that have been used to estimate severity of neuronal damage and prognosis in various CNS diseases. One previous study has been performed on VZV in the central nervous system (CNS), but patients with facial palsy have not been specifically studied. Methods: 28 patientswith VZV facial palsy, diagnosed by detection of VZV DNA in CSF by PCR, were retrospectively identified. GFAp, NFL and S-100 were measured in stored CSF samples and compared with a control group (n=52). Medical records were studied for relevant patient data such as severity of symptoms, treatment and laboratory parameters. Results: CSF concentrations of NFL and GFAp were significantly elevated compared to controls (p<0.01 and p<0.05) and S-100 concentrations were reduced. Additionally, NFL kinetics indicated slightly increasing concentrations in CSF samples drawn more than seven days after onset of neurological symptoms. Viral load (VZV DNA copies/ml) correlated with both NFL (Spearman r=0.51; p<0.01) and GFAp (Spearman r=0.54; p<0.01). No correlations were found between biomarkers and severity of symptoms, clinical outcome at follow-up, or treatment with aciclovir prior to CSF sampling in this small study. Conclusion: In this first study on biomarkers in facial palsy caused by VZV, we identified a pattern of elevated NFL, elevated GFAp and decreased S-100 compared to controls. Increased NFL levels reflect axonal damage, and elevated levels of GFAp, in combination with decreased concentrations of S-100 , indicate astrogliosis rather than damage to the astroglial cell membrane. Biomarkers of neuron and glial cell damage can be used to understand pathogenesis, and in future studies assessment of these biomarkers in relation to treatment and clinical outcome should be explored. http://dx.doi.org/10.1016/j.jcv.2015.07.137 Abstract No: 1682 Presentation at ESCV 2015: Poster 1 False negative influenza A virus subtype H3N2 in Prodesse GenProbe ProFlu+ PCR assay in season 2014–2015 N. Kirkby1,∗, T.N. Thomsen1, R. Trebbien2, K. Vorborg2, J. Ronn2, T.K. Fischer2, C.B. Christiansen1 1 Department of Clinical Microbiology, Rigshospitalet, Copenhagen, Denmark 2 National Influenza Center, Virological Surveillance and Research Department of Microbiological

Brain function in children with untreated epilepsy: Relationship to biomarkers of brain damage

Many studies have reported cognitive and behavioral abnormalities with recurrent seizures in adults. Similar evidence from the pediatric population is scarce and controversial. We aimed to investigate the effect of recurrent seizures on the developing brain. Included were 42 children with epilepsy (mean age 14.1±1.72 yr) and 30 healthy children for comparison. Patients had recurrent untreated epilepsy (generalized or focal). Negative attitudes and misconceptions about epilepsy are common in developing countries, often resulting in neglect of medical services and treatment. Epilepsy is greatly misunderstood by the public, and is attributed to spiri- tual causes such as the devil or mistaken as odd behavior or daydreaming. Another misconception is that medications will harm the child. Intelligence quotient (IQ) and cognition were examined using Wechsler Intelligence Scale for Children and Stanford Binet Subsets Test version 4 (SBST4). Serum levels of neuron-specific enolase (NSE) and S100s proteins, sensitive markers of neuronal and glial cell damage were measured. Compared to controls, patients had lower mean score of full scale IQ on the Wechsler Intelli- gence Scale for Children (P = 0.045), particularly performance IQ scores (P <0.01), and comprehension, pattern analysis, quantita- tion, bead memory and memory for sentences of SBST4 (P = 0.045; P =0 .013,P = 0.007, P = 0.002; P = 0.035), but not for NSE or S100s. Severe epileptogenic (EEG) records were observed in children with lower IQ. Serum concentrations of NSE and S100s were lower in children with higher seizure frequency but did not reach significance compared to controls. Significant correlation was observed between full scale IQ and duration of illness (r = �0.430, P = 0.035), number of seizures (r = �0.580, P = 0.005) and sever- ity of electroencephalography changes (r = �0.450, P = 0.052), but not with S100s or NSE levels. Lower intelligence and poor cog- nitive performance were common with recurrent childhood epilepsy. Functional brain abnormalities without structural brain injury may likely be the cause. It seems that serum levels of NSE and S100s are not sensitive markers for structural or minimal brain damage in children with untreated epilepsy. Thus, early recognition and optimal seizure control is necessary to prevent the subse- quent damaging effects on the brain due to prolonged and recurrent seizures and subclinical epileptiform activity. Looking for addi- tional, more specific markers of brain injury is necessary, elevated serum levels of NSE and S100s were not detected.

Ebselen by modulating oxidative stress improves hypoxia-induced macroglial Müller cell and vascular injury in the retina

Oxidative stress is an important contributor to glial and vascular cell damage in ischemic retinopathies. We hypothesized that ebselen via its ability to reduce reactive oxygen species (ROS) and augment nuclear factor-like 2 (Nrf2) anti-oxidants would attenuate hypoxia-induced damage to macroglial Müller cells and also lessen retinal vasculopathy. Primary cultures of rat Müller cells were exposed to normoxia (21% O2), hypoxia (0.5% O2) and ebselen (2.5 μM) for up to 72 h. Oxygen-induced retinopathy (OIR) was induced in C57BL/6J mice while control mice were housed in room air. Mice received vehicle (saline, 5% dimethyl sulfoxide) or ebselen (10 mg/kg) each day between postnatal days 6–18. In cultured Müller cells, flow cytometry for dihydroethidium revealed that ebselen reduced the hypoxia-induced increase in ROS levels, whilst increasing the expression of Nrf2-regulated anti-oxidant genes, heme oxygenase 1, glutathione peroxidase-1, NAD(P)H dehydrogenase quinone oxidoreductase 1 and glutamate-cysteine ligase. Moreover, in Müller cells, ebselen reduced the hypoxia-induced increase in protein levels of pro-angiogenic and pro-inflammatory factors including vascular endothelial growth factor, interleukin-6, monocyte chemoattractant-protein 1 and intercellular adhesion molecule-1, and the mRNA levels of glial fibrillary acidic protein (GFAP), a marker of Müller cell injury. Ebselen improved OIR by attenuating capillary vaso-obliteration and neovascularization and a concomitant reduction in Müller cell gliosis and GFAP. We conclude that ebselen protects against hypoxia-induced injury of retinal Müller cells and the microvasculature, which is linked to its ability to reduce oxidative stress, vascular damaging factors and inflammation. Agents such as ebselen may be potential treatments for retinopathies that feature oxidative stress-mediated damage to glia and the microvasculature.

Right Dorsolateral Frontal Lobe N-Acetyl Aspartate and Myoinositol Concentration Estimation in Type 2 Diabetes with Magnetic Resonance Spectroscopy.

Chronic hyperglycaemia in type 2 diabetes, effects the central nervous system by altering the concentrations of brain metabolites like N-acetyl aspartate (NAA) and myoinositol (mI), which are indicators of neuronal integrity and glial cell damage respectively. Dorsolateral frontal lobe is associated with aspects of cognition especially right frontal lobe is involved in episodic memory retrieval, ninety percent of the diabetic cases are type 2 in nature globally and yoga is very effective in stabilizing the brain metabolites by bringing the blood glucose levels to near or within the physiological range in type 2 diabetes. The aim of the study was to observe the effects of yogasana and pranayama on glycosilated haemoglobin (HbA1c) levels and right dorsolateral frontal cortical NAA and mI concentration in type 2 diabetic subjects. It's a case control study. Sixty eight type 2 diabetic subjects of both the sex, aged between 35-65 years are included in the study, subjects are divided in to test and control group 34 each. Test group subjects did the yogasana and pranayama for a period of 6 months, 6 days in a week, 45-60 minutes daily under the supervision of a qualified yoga teacher. Control group subjects are not on any specific exercise regimen. Both the group subjects are taking oral hypoglycaemic agents. HbA1c levels are measured using the Bio-Rad D-10™ haemoglobin A1c program and Magnetic Resonance Spectroscopy (MRS) is used in assessing the metabolite concentrations. Analysis of data was done by using unpaired t-test. P-value for HbA1c level is <0.001, which is highly significant statistically. P-value for NAA was < 0.02 and for myoinositol was < 0.01, which are statistically significant. HbA1c levels in control and test group subjects are 7.7 ± 1.84 and 6.02 ± 0.46 respectively. NAA concentrations in the right dorsolateral frontal lobe of control and test group are 1.44 ± 0.15 and 1.54 ± 0.19 respectively. The mI concentrations in the right dorsolateral frontal lobe of control and test group are 0.61 ± 0.22 and 0.47 ± 0.24 respectively. Yogasana and pranayama minimized the neuronal and glial cellular damage in test group, which is evident by minimal changes in right dorsolateral frontal lobe NAA and mI levels in type 2 diabetic subjects.

Purinergic signalling in neuroregeneration.

Purinergic signalling in neuroregeneration.

Терапевтичний вплив Церебрала за умов нейродегенерації, викликаної порушенням функції гена swiss cheese у Drosophila melanogaster

It was found that Cerebral medicine has a therapeutic effect on aging of D. melanogaster individuals with neurodegeneration caused by altered functioning of swiss cheese gene ( sws ). After Сerebral treatment survival of old mutants sws olfE . was improved. Comparison of brain tissue histological sections of twenty days old males grown on standard nutrient medium and the medium with C. still showed manifestation of the mutant phenotype after application of the drug. However, penetrance of the neurodegenerative phenotype decreased by 10 % and this change correlated with an increase in the viability of aging individuals. We have created a functional knockout of sws gene in glial cells using Gal4-UAS system to test the effect of the drug in the conditions of shortage sws in glial cells. Genotype of such individual was Repo-Gal4&gt;UAS-sws-RNAi . After analysis of these flies, we found specific pathology of glial phenotype, namely: considerable vacuolization in brain tissue in the region of the transition lamina to retina and medulla. In individuals with functional knockout of sws in glia, size of neurodegeneration area decreased by 34.5 % after Cerebral treatment, and 28.4 % in case of using its low molecular weight fraction. No significant differences in the effects of Cerebral and its low molecular weight fraction were found. Our results allow to conclude that the active component of C is its low molecular weight fraction. This drug may be effective in treatment of brain pathologies with a primary damage of glial cells. Keywords: neurodegeneration, Drosophila melanogaster , swiss cheese , Gal4-UAS functional inactivation, Cerebral.

Pathophysiology, diagnosis, and treatment of radiation necrosis in the brain.

New radiation modalities have made it possible to prolong the survival of individuals with malignant brain tumors, but symptomatic radiation necrosis becomes a serious problem that can negatively affect a patient’s quality of life through severe and lifelong effects. Here we review the relevant literature and introduce our original concept of the pathophysiology of brain radiation necrosis following the treatment of brain, head, and neck tumors. Regarding the pathophysiology of radiation necrosis, we introduce two major hypotheses: glial cell damage or vascular damage. For the differential diagnosis of radiation necrosis and tumor recurrence, we focus on the role of positron emission tomography. Finally, in accord with our hypothesis regarding the pathophysiology, we describe the promising effects of the anti-vascular endothelial growth factor antibody bevacizumab on symptomatic radiation necrosis in the brain.

Pineal gland function is required for colon antipreneoplastic effects of physical exercise in rats.

Light-at-night exposure enhances the risk of cancer. Colon cancer is among the most dangerous tumors affecting humankind. Physical exercise has shown positive effects against colon cancer. Here, we investigated whether pineal gland modulates antipreneoplastic effects of physical exercise in the colon. Surgical and non-surgical pineal impairments were performed to clarify the relationship between the pineal gland activity and manifestation of colonic preneoplastic lesions. Next, a progressive swimming training was applied in rats exposed or not to either non-surgical pineal impairment or carcinogen treatment for 10 weeks. Both surgical and non-surgical pineal impairments increased the development of colon preneoplasia. It was further found that impairing the pineal gland function, higher rates of DNA damage were induced in colonic epithelial and enteric glial cells. Physical exercise acted positively against preneoplasia, whereas impairing the pineal function with constant light exposure disrupts its positive effects on the development of preneoplastic lesions in the colon. This was yet related to increased DNA damage in glial cells and enteric neuronal activation aside from serum melatonin levels. Our findings suggest that protective effects of physical exercise against colon cancer are dependent on the pineal gland activity.

Oxidative Glial Cell Damage Associated with White Matter Lesions in the Aging Human Brain.

White matter lesions (WML) are common in brain aging and are associated with dementia. We aimed to investigate whether oxidative DNA damage and occur in WML and in apparently normal white matter in cases with lesions. Tissue from WML and control white matter from brains with lesions (controls lesional) and without lesions (controls non‐lesional) were obtained, using post‐mortem magnetic resonance imaging‐guided sampling, from the Medical Research Council Cognitive Function and Ageing Study. Oxidative damage was assessed by immunohistochemistry to 8‐hydroxy‐2′‐deoxoguanosine (8‐OHdG) and Western blotting for malondialdehyde. DNA response was assessed by phosphorylated histone H2AX (γH2AX), p53, senescence markers and by quantitative Reverse transcription polymerase chain reaction (RT‐PCR) panel for candidate DNA damage‐associated genes. 8‐OHdG was expressed in glia and endothelium, with increased expression in both WML and controls lesional compared with controls non‐lesional (P < 0.001). γH2Ax showed a similar, although attenuated difference among groups (P = 0.03). Expression of senescence‐associated β‐galactosidase and p16 suggested induction of senescence mechanisms in glia. Oxidative DNA damage and a DNA damage response are features of WML pathogenesis and suggest candidate mechanisms for glial dysfunction. Their expression in apparently normal white matter in cases with WML suggests that white matter dysfunction is not restricted to lesions. The role of this field‐effect lesion pathogenesis and cognitive impairment are areas to be defined.

Comparison of the radiosensitivities of neurons and glial cells derived from the same rat brain.

Non-proliferating cells, such as mature neurons, are generally believed to be more resistant to X-rays than proliferating cells, such as glial and vascular endothelial cells. Therefore, the late adverse effects of radiotherapy on the brain have been attributed to the radiation-induced damage of glial and vascular endothelial cells. However, little is known about the radiosensitivities of neurons and glial cells due to difficulties in culturing these cells, particularly neurons, independently. In the present study, primary dissociated neurons and glial cultures were prepared separately from the hippocampi and cerebrum, respectively, which had been obtained from the same fetal rat on embryonic day 18. X-irradiations of 50 Gy were performed on the cultured neurons and glial cells at 7 and 21 days in vitro (DIV). The cells were fixed at 24 h after irradiation. Terminal deoxynucleotidyl transferase-mediated dUTP nick end labeling was then performed to measure the apoptotic indices (AIs). The AIs of non-irradiated and irradiated neurons at 7 DIV were 23.7±6.7 and 64.9±4.8%, and those at 21 DIV were 52.1±17.4 and 44.6±12.5%, respectively. The AIs of non-irradiated and irradiated glial cells at 7 DIV were 5.8±1.5 and 78.4±3.3% and those at 21 DIV were 9.6±2.6 and 86.3±4.9%, respectively. Glial cells and neurons were radiosensitive at 7 DIV. However, while glial cells were radiosensitive at 21 DIV, neurons were not.

Titanium dioxide nanoparticles induce strong oxidative stress and mitochondrial damage in glial cells

Titanium dioxide nanoparticles (TiO2 NPs) are widely used in the chemical, electrical, and electronic industries. TiO2 NPs can enter directly into the brain through the olfactory bulb and can be deposited in the hippocampus region; therefore, we determined the toxic effect of TiO2 NPs on rat and human glial cells, C6 and U373, respectively. We evaluated some events related to oxidative stress: (1) redox-signaling mechanisms by oxidation of 2′,7′-dichlorodihydrofluorescein diacetate; (2) peroxidation of lipids by cis-parinaric acid; (3) antioxidant enzyme expression by PCR in real time; and (4) mitochondrial damage by MitoTracker Green FM staining and Rh123. TiO2 NPs induced a strong oxidative stress in both glial cell lines by mediating changes in the cellular redox state and lipid peroxidation associated with a rise in the expression of glutathione peroxidase, catalase, and superoxide dismutase 2. TiO2 NPs also produced morphological changes, damage of mitochondria, and an increase in mitochondrial membrane potential, indicating toxicity. TiO2 NPs had a cytotoxic effect on glial cells; however, more in vitro and in vivo studies are required to ascertain that exposure to TiO2 NPs can cause brain injury and be hazardous to health.

Genistein Inhibited Amyloid-β induced Inflammatory Damage in C6 Glial Cells

β-amyloid-induced inflammation has been implicated in the early pathologic events in neurodegenerative diseases. The anti-inflammation potential of genistein (GEN) had been proved recently in our previous studies. We undertook this study to investigate the effects of GEN on inflammation induced by β-amyloid25-35 treatment and the possible molecular mechanisms in C6 glial cells. C6 cells were pre-incubated with GEN for 2 h followed by the incubation with β-amyloid 25-35 (Aβ25-35) for another 24 h. Inflammatory factors were detected by ELISA. The mRNA and protein expression of nuclear factor κB (NF-κB) p65 was measured using RT-PCR and Western blot, respectively. After inhibiting the NF-κBp65 mRNA expression by using short interfering RNAs (siRNAs) technique, the changes of inflammatory factors levels were detected again. GEN inhibited the production of inflammatory factors induced by Aβ25-35 treatment. Aβ25-35 treatment had no effect on the mRNA expression of NF-κBp65 but upregulated the protein expression of NF-κBp65. However, this upregulation effect on NF-κBp65 protein expression was alleviated by GEN pretreatment. After inhibiting NF-κBp65 mRNA expression by using siRNA technique, the effects of Aβ25-35 or GEN on the inflammatory factor generation were inhibited. These results indicated that GEN exhibited anti-inflammatory effects through regulating NF-κB signaling pathway in Aβ25-35-treated C6 glial cells.

P 19. Threshold for neurodegeneration and microstructural changes in different cell types induced by anodal transcranial direct current stimulation

Introduction Transcranial direct current stimulation (tDCS) has been shown to modulate cortical excitability and to improve motor learning (Nitsche and Paulus, 2000; Reis et al., 2009; Fritsch et al., 2010). To date there is no data available on the safety aspects of tDCS covering a broad range of stimulation intensities, thus limitations for dosages applied to humans are still based empirically on other types of electrical brain stimulation (Agnew and McCreery, 1987). Objectives The aim of this study was to investigate lesion threshold, accompanying neurodegeneration and possible microstructural changes in glial cells in an animal model of tDCS. Methods The tDCS electrode was placed in a screw tube surgically fixed on the skull above the left primary motor cortex of 47 Male Sprague Dawley rats. Anodal tDCS was applied in different intensities (254.8, 127.4, 63.7, 31.8, 15.9 and 8A/sqm) or as sham stimulation for 20min under slight isoflurane anesthesia. For each intensity animals were sacrificed either 24h (acute effects) or 7days (chronic effects) after intervention. Histological analyses of neurodegeneration (HE-staining, Fluoro-Jade C), astrocyte (anti-GFAP) and microglial (anti-CD11b [OX-42]) cell counts/density and/or morphological changes were evaluated. Results Macroscopical lesions could be observed at tDCS intensity of 127A/sqm and above whereas the lesion dose 50 (LD 50) for microscopical neurodegeneration was determined at 60A/sqm. Threshold for damage in neuronal and glial cells and change in morphology (activation) was identical. These changes could be detected both in the acute and chronic group. Notably, signs of still ongoing neurodegeneration, though to a slighter extent, were seen 7days after stimulation. Brain swelling, which was seen underneath the stimulation electrode 24h following the highest intensity used, was not present one week after stimulation. Conclusions Our results demonstrate that the LD 50 intensity of anodal tDCS for unwanted structural effects is 75 times higher than the intensities applied to humans to date. Additional safety derives from the fact that structures between brain and stimulation electrode, which lead to energy absorbtion, are thicker in humans compared to rats. Cell death, as a trigger for glial reaction, continues even 7days after the intervention. Based on our results we conclude that higher tDCS intensities in human studies can be applied without risking structural damage.

Experimental treatment of superior venous congestion during cardiopulmonary bypass

Superior venous outflow obstruction affects cerebral perfusion negatively by reducing cerebral perfusion pressure (CPP). We present a randomized study designed to compare two alternative strategies to preserve the CPP during superior vena cava (SVC) congestion and cardiopulmonary bypass (CPB). Fourteen pigs on bi-caval CPB were subjected to 75% occlusion of the SVC flow. CPP was restored either by vasopressor treatment (VP, n = 7) or by partial relief (PR) of the congestion (n = 7). The cerebral effects of the interventions were studied for 60 min with intracranial pressure (ICP) monitoring, cerebral blood flow measurement, the near-infrared light spectroscopy tissue oxygen saturation index (StO2), arterial and venous blood gas analyses and serial measurements of the glial cell damage marker protein S100β. Both strategies restored the CPP to baseline levels and no signs of severe ischaemia were observed. In the PR group, the venous and ICPs were normalized in response to the intervention, while in the VP group those parameters remained elevated throughout the experiment. The haemoglobin oxygen saturation in the sagittal sinus (SsagO2) was increased by both VP and PR, while significant improvement in the StO2 was observed only in the PR group. The S100β concentrations were similar in the two groups. Experimental SVC obstruction during CPB may reduce the CPP, resulting in impaired cerebral perfusion. Both vasopressor treatment and improved venous drainage can, in the short term, individually restore the CPP during these circumstances.

Time‐dependent changes of protein biomarker levels in the cerebrospinal fluid after blast traumatic brain injury

Time-dependent changes of protein biomarkers in the cerebrospinal fluid (CSF) can be used to identify the pathological processes in traumatic brain injury (TBI) as well as to follow the progression of the disease. We obtained CSF from a large animal model (swine) of blast-induced traumatic brain injury prior to and at 6, 24, 72 h, and 2 wk after a single exposure to blast overpressure, and determined changes in the CSF levels of neurofilament-heavy chain, neuron-specific enolase, brain-specific creatine kinase, glial fibrillary acidic protein, calcium-binding protein β (S100β), Claudin-5, vascular endothelial growth factor, and von Willebrand factor using reverse phase protein microarray. We detected biphasic temporal patterns in the CSF concentrations of all tested protein markers except S100β. The CSF levels of all markers were significantly increased 6 h after the injury compared to preinjury levels. Values were then decreased at 24 h, prior to a second increase in all markers but S100β at 72 h. At 2 wk postinjury, the CSF concentrations of all biomarkers were decreased once again; brain-specific creatine kinase, Claudin-5, von Willebrand factor, and S100β levels were no longer significantly higher than their preinjury values while neurofilament-heavy chain, neuron-specific enolase, vascular endothelial growth factor, and glial fibrillary acidic protein levels remained significantly elevated compared to baseline. Our findings implicate neuronal and glial cell damage, compromised vascular permeability, and inflammation in blast-induced traumatic brain injury, as well as demonstrate the value of determining the temporal pattern of biomarker changes that may be of diagnostic value.

Neuroprotective effect of preoperatively induced mild hypothermia as determined by biomarkers and histopathological estimation in a rat subdural hematoma decompression model

In patients who have sustained a traumatic brain injury (TBI), hypothermia therapy has not shown efficacy in multicenter clinical trials. Armed with the post hoc data from the latest clinical trial (National Acute Brain Injury Study: Hypothermia II), the authors hypothesized that hypothermia may be beneficial in an acute subdural hematoma (SDH) rat model by blunting the effects of ischemia/reperfusion injury. The major aim of this study was to test the efficacy of temperature management in reducing brain damage after acute SDH. The rats were induced with acute SDH and placed into 1 of 4 groups: 1) normothermia group (37°C); 2) early hypothermia group, head and body temperature reduced to 33°C 30 minutes prior to craniotomy; 3) late hypothermia group, temperature lowered to 33°C 30 minutes after decompression; and 4) sham group, no acute SDH (only craniotomy with normothermia). To assess for neuronal and glial cell damage, the authors analyzed microdialysate concentrations of GFAP and ubiquitin carboxyl-terminal hydrolase-L1 (UCH-L1) by using a 100-kD probe. Fluoro-Jade B-positive neurons and injury volume with 2,3,5-triphenyltetrazolium chloride staining were also measured. In the early phase of reperfusion (30 minutes, 2.5 hours after decompression), extracellular UCH-L1 in the early hypothermia group was significantly lower than in the normothermia group (early, 4.9 ± 1.0 ng/dl; late, 35.2 ± 12.1 ng/dl; normothermia, 50.20 ± 28.3 ng/dl; sham, 3.1 ± 1.3 ng/dl; early vs normothermia, p < 0.01; sham vs normothermia, p < 0.01, analyzed using ANOVA followed by a post hoc Bonferroni test). In the late phase of reperfusion (> 2.5 hours after decompression), extracellular GFAP in the early hypothermia group was also lower than in the normothermia and late hypothermia groups (early, 5.5 ± 2.9 ng/dl; late, 7.4 ± 3.4 ng/dl; normothermia, 15.3 ± 8.4 ng/dl; sham, 3.3 ± 1.0 ng/dl; normothermia vs sham; p < 0.01). The number of Fluoro-Jade B-positive cells in the early hypothermia group was significantly smaller than that in the normothermia group (normothermia vs early: 774,588 ± 162,173 vs 180,903 ± 42,212, p < 0.05). Also, the injury area and volume were smaller in the early hypothermia group in which hypothermia was induced before craniotomy and cerebral reperfusion (early, 115.2 ± 15.4 mm(3); late, 344.7 ± 29.1 mm(3); normothermia, 311.2 ± 79.2 mm(3); p < 0.05). The data suggest that early, preoperatively induced hypothermia could mediate the reduction of neuronal and glial damage in the reperfusion phase of ischemia/reperfusion brain injury.

Qualitу of life at children with critical hydrocephalus

Introduction. In article modern views at a problem of treatment of critical hydrocephalus at children were analysed.Materials and methods. The purpose of research was to study the results of shunt operations of 96 children with critical hydrocephalus. Age of patients was from three months to two years. Ventriculoperitoneostomy was performed in all children. Histological research of biopsy materials of cerebral tissue were conducted in 10 cases. A catamnesis was followed for 2–17 years.Results. In 49% cases after operation good (in 19%) or satisfactory (in 30%) quality of patients’ life was achieved. At microscopic research of brain tissue the correlation of destructive changes rate and hydrocephalus severity, caused not only by hypertension, was established.Conclusions. At critical hydrocephalus changes in brain tissue mostly concern damage of glial cells. Maintenance of considerable part of neurons and glial cells proliferation are important pre-condition for neural cells reparation and cerebral functions renewing. Inflammatory and vascular etiology of hydrocephalus have negative influence.