Myelin Disruption Research Articles

Role of myelin auto-antigens in pain: a female connection.

Following injury to the peripheral nerve, pain secondary to low threshold innocuous mechanical stimulation (mechanical allodynia) is commonly observed. Its origins are poorly understood and the pain is often refractory to common analgesic therapeutics. The past two decades has brought major advances in our understanding of the complexity of systems that underlie processing of neuropathic pain (pain arising from damage or disease of the somatosensory system). Beginning with the argument by Robert Galambos in the 1960s that glia played a major regulatory role in neural function, current thinking has evolved to emphasize the major role of glia-mediated neuroinflammation in the development of a chronic pain state. Recent use of unbiased high-throughput genetic and proteomics screening technology in preclinical models of nerve injury associated with pain states, attention has become focused on the role of T cell related genes and adaptive immune pathways (Costigan et al., 2009; Liu et al., 2012). In this perspective, we discuss the organizing principle that following local nerve injury, the ability to evoke a pain state with low-threshold, otherwise innocuous, mechanical stimulation (light touch), represents a local, sex dependent, manifestation of an adaptive immune response mediated by myelin basic protein (MBP).

Neurophysiological effects of needle trauma and intraneural injection in a porcine model: a pilot study

Neurophysiological data are lacking in the research of nerve injury during regional anaesthesia. The aim of this pilot study was to establish a large animal model in order to test the hypothesis that needle trauma alone or in combination with intraneural injection would result in measurable nerve injury. The experimental set-up was elaborated in four pre-test animals. In the remaining animals (n = 11), 22 sciatic nerves were randomly assigned to one of four groups: needle trauma (n = 5) generated by ultrasound-guided forced needle advancement; intraneural injection of 2.5 ml saline (n = 6); intraneural injection of 5 ml saline (n = 6); extraneural injection of 5 ml saline (n = 5) as control group. Compound muscle action potential (CMAP) amplitudes as well as latencies were taken as outcome parameter and monitored over 180 min. Sonographic assessments were performed simultaneously. Following needle trauma and intraneural injection, CMAP amplitudes declined significantly over 180 min (P < 0.001). The control group showed no electrophysiological alterations. At 60 min, decreases in amplitude were significant after needle trauma (P = 0.04) and intraneural injection of 2.5 ml (P = 0.045), and highly significant after injection of 5 ml (P = 0.006) when compared to controls. Sustained nerve swelling was observed after intraneural injection, but not after needle trauma and perineural injection. Isolated mechanical trauma caused by forced needle advancement alone or in combination with intraneural injection of saline was followed by a significant decline in CMAP amplitudes indicating conduction block due to disruption of myelin or axon loss (pseudo-conduction block).

Proteomic analysis of cortical brain tissue from the BTBR mouse model of autism: Evidence for changes in STOP and myelin-related proteins

Autism is a neurodevelopmental disorder characterized by abnormal reciprocal social interactions, communication deficits, and repetitive behaviors with restricted interests. However, the widely accepted biomarkers for autism are still lacking. In this study, we carried out a quantitative proteomic profiling study of cortical brain tissue from BTBR T+Itpr3tf (BTBR) mice, a mouse model that displays an autism-like phenotype. Using isobaric tag for relative and absolute quantification (iTRAQ) coupled with LC–MS/MS, a total of 3611 proteins were quantitated in mouse cortices. As compared to C57BL/6J (B6) mice, 126 differentially expressed proteins were found in the brain from BTBR mice. The functional annotation and categories of differentially expressed proteins were analyzed. Especially, the stable tubule only polypeptide (STOP) protein and myelin-related proteins down-regulated significantly in BTBR mice were confirmed by Western blotting. Furthermore, the BTBR mice displayed reduced levels of staining with ferric alum in comparison to B6 controls, indicative of myelin disruption. Finally, we propose that reduced STOP expression in the brain could be involved in the mediation of autism-like behaviors through impairments of myelination in oligodendrocytes and synaptic function in neurons. Manipulation of STOP protein could be a promising avenue for therapeutic interventions to autism.

Stimulation-induced Ca(2+) influx at nodes of Ranvier in mouse peripheral motor axons.

In peripheral myelinated axons of mammalian spinal motor neurons, Ca(2+) influx was thought to occur only in pathological conditions such as ischaemia. Using Ca(2+) imaging in mouse large motor axons, we find that physiological stimulation with trains of action potentials transiently elevates axoplasmic [C(2+)] around nodes of Ranvier. These stimulation-induced [Ca(2+)] elevations require Ca(2+) influx, and are partially reduced by blocking T-type Ca(2+) channels (e.g. mibefradil) and by blocking the Na(+)/Ca(2+) exchanger (NCX), suggesting an important contribution of Ca(2+) influx via reverse-mode NCX activity. Acute disruption of paranodal myelin dramatically increases stimulation-induced [Ca(2+)] elevations around nodes by allowing activation of sub-myelin L-type (nimodipine-sensitive) Ca(2+) channels. The Ca(2+) that enters myelinated motor axons during normal activity is likely to contribute to several signalling pathways; the larger Ca(2+) influx that occurs following demyelination may contribute to the axonal degeneration that occurs in peripheral demyelinating diseases. Activity-dependent Ca(2+) signalling is well established for somata and terminals of mammalian spinal motor neurons, but not for their axons. Imaging of an intra-axonally injected fluorescent [Ca(2+)] indicator revealed that during repetitive action potential stimulation, [Ca(2+)] elevations localized to nodal regions occurred in mouse motor axons from ventral roots, phrenic nerve and intramuscular branches. These [Ca(2+)] elevations (∼ 0.1 μm with stimulation at 50 Hz, 10 s) were blocked by removal of Ca(2+) from the extracellular solution. Effects of pharmacological blockers indicated contributions from both T-type Ca(2+) channels and reverse mode Na(+)/Ca(2+) exchange (NCX). Acute disruption of paranodal myelin (by stretch or lysophosphatidylcholine) increased the stimulation-induced [Ca(2+)] elevations, which now included a prominent contribution from L-type Ca(2+) channels. These results suggest that the peri-nodal axolemma of motor axons includes multiple pathways for stimulation-induced Ca(2+) influx, some active in normally-myelinated axons (T-type channels, NCX), others active only when exposed by myelin disruption (L-type channels). The modest axoplasmic peri-nodal [Ca(2+)] elevations measured in intact motor axons might mediate local responses to axonal activation. The larger [Ca(2+) ] elevations measured after myelin disruption might, over time, contribute to the axonal degeneration observed in peripheral demyelinating neuropathies.

Animal Models for Progressive Multifocal Leukoencephalopathy.

Progressive multifocal leukoencephalopathy (PML) is a severe demyelinating disease of the CNS caused by the human polyomavirus JC (JCV). JCV replication occurs only in human cells and investigation of PML has been severely hampered by the lack of an animal model. The common feature of PML is impairment of the immune system. The key to understanding PML is working out the complex mechanisms that underlie viral entry and replication within the CNS and the immunosurveillance that suppresses the virus or allows it to reactivate. Early models involved the simple inoculation of JCV into animals such as monkeys, hamsters, and mice. More recently, mouse models transgenic for the gene encoding the JCV early protein, T-antigen, a protein thought to be involved in the disruption of myelin seen in PML, have been employed. These animal models resulted in tumorigenesis rather than demyelination. Another approach is to use animal polyomaviruses that are closely related to JCV but able to replicate in the animal such as mouse polyomavirus and SV40. More recently, novel models have been developed that involve the engraftment of human cells into the animal. Here, we review progress that has been made to establish an animal model for PML, the advances and limitations of different models and weigh future prospects.

Lanthionine ketimine ester provides benefit in a mouse model of multiple sclerosis

Lanthionine ketimine (LK) is a natural sulfur amino acid metabolite which binds to collapsin response mediator protein-2 (CRMP2), an abundant brain protein that interacts with multiple partners to regulate microtubule dynamics, neurite growth and retraction, axonal transport, and neurotransmitter release. LK ethyl-ester (LKE) is a cell-permeable synthetic derivative that promotes neurogenesis, suppresses nitric oxide production from microglia, and reduces neurotoxicity of microglia-conditioned medium. These properties led us to test the effects of LKE in experimental autoimmune encephalomyelitis (EAE), a commonly used mouse model of multiple sclerosis. Female C57Bl/6 mice were immunized with myelin oligodendrocyte glycoprotein peptide 35-55 to develop a chronic disease. LKE was provided in the chow at 100 ppm, ad libitum beginning when the mice reached moderate clinical signs. Over the following 4 weeks the LKE-treated mice showed a significant reduction in clinical signs compared to vehicle-treated mice. LKE dose dependently reduced IFNγ production from splenic T cells, but had no effect on IL-17 production suggesting protective effects were mediated within the CNS. Electron microscopy revealed that, compared to sham mice, EAE mice had significant neurodegeneration in both the optic nerve and spinal cord, which was reduced in the LKE-treated mice. In contrast only minimal disruption of myelin was observed at this time point. In the optic nerve, measurements of axon caliber and myelin thickness showed little changes between sham and EAE mice, however, treatment with LKE increased the percentage of axons with thicker myelin and with larger axon calibers. In the spinal cord, only smaller effects of LKE on myelin thickness were observed. The effects of LKE were associated with a reduced relative level of phosphorylated CRMP2 to CRMP2. Together, these results demonstrate that LKE reduces neurodegeneration in a chronic EAE model of MS, which could have translation potential for treatment of progressive forms of MS.

Functional regeneration of the brain: white matter matters.

Functional regeneration of the brain: white matter matters.

Subcellular localization of Rho GTPases: implications for axon regeneration.

Subcellular localization of Rho GTPases: implications for axon regeneration.

Spreading depression transiently disrupts myelin via interferon-gamma signaling

Multiple sclerosis and migraine with aura are clinically correlated and both show imaging changes suggestive of myelin disruption. Furthermore, cortical myelin loss in the cuprizone animal model of multiple sclerosis enhances susceptibility to spreading depression, the likely underlying cause of migraine with aura. Since multiple sclerosis pathology involves inflammatory T cell lymphocyte production of interferon-gamma and a resulting increase in oxidative stress, we tested the hypothesis that spreading depression disrupts myelin through similar signaling pathways. Rat hippocampal slice cultures were initially used to explore myelin loss in spreading depression, since they contain T cells, and allow for controlled tissue microenvironment. These experiments were then translated to the in vivo condition in neocortex. Spreading depression in slice cultures induced significant loss of myelin integrity and myelin basic protein one day later, with gradual recovery by seven days. Myelin basic protein loss was abrogated by T cell depletion, neutralization of interferon-gamma, and pharmacological inhibition of neutral sphingomyelinase-2. Conversely, one day after exposure to interferon-gamma, significant reductions in spreading depression threshold, increases in oxidative stress, and reduced levels of glutathione, an endogenous neutral sphingomyelinase-2 inhibitor, emerged. Similarly, spreading depression triggered significant T cell accumulation, sphingomyelinase activation, increased oxidative stress, and reduction of gray and white matter myelin in vivo. Myelin disruption is involved in spreading depression, thereby providing pathophysiological links between multiple sclerosis and migraine with aura. Myelin disruption may promote spreading depression by enhancing aberrant excitability. Thus, preservation of myelin integrity may provide novel therapeutic targets for migraine with aura.

PL-01 * A PRECLINICAL JUVENILE RAT MODEL OF BRAIN INJURY AFTER FRACTIONATED WHOLE BRAIN IRRADIATION

BACKGROUND: Late effects of radiotherapy in survivors of pediatric brain tumors are life-long and debilitating. We describe the behavior and imaging characteristics of a rat model given fractionated whole brain radiation equivalent to doses used to treat children with high-risk medulloblastoma. METHODS: One month-old Fischer rats were given 9 fractions of either 0 or 3 Gray (Gy). A third group was given eight 3Gy fractions followed by a single 10Gy “top off” to serve as a positive control. The 27Gy dose is biologically equivalent to 36Gy given to children. The open-field exploration task and the elevated plus maze were performed at 4 months post-irradiation. Declarative memory was tested by novel object recognition at 4- and 7-months post-irradiation. Magnetic resonance imaging, including diffusion tensor imaging (DTI) and spectroscopy (MRS), was obtained at baseline, 4-, and 7-months post-irradiation. RESULTS: 4 months post-irradiation, there were no differences in the open-field exploration task among the groups. Both the 27Gy (p = 0.002) and 34Gy (p = 0.04) groups demonstrated less exploration of the open arms of the elevated plus maze. There were no differences in novel object recognition at 4 months, but both irradiated groups demonstrated deficits by 7 months post-irradiation (p27 = 0.02, p34 = 0.02). Fractional anisotropy of the corpus callosum at 7 months post-irradiation was decreased only in the 34Gy group (p = 0.02) and not in the 27Gy group. N-acetyl aspartate remained higher than controls at 7-months post-irradiation in both hippocampus (p27 < 0.01, p34 < 0.03) and corpus callosum (p27 < 0.08, p34 < 0.04). CONCLUSIONS: This model of a juvenile rat given fractionated, clinically-relevant doses of radiation displays cognitive deficits described in survivors of medulloblastoma who have received radiotherapy. Imaging characteristics indicate a potential disruption of the normal developmental myelination by MRS that correlates with memory deficits and may be useful for evaluating novel therapeutic strategies of radiation mitigation.

Evaluation of Impact-Induced Traumatic Brain Injury in the Göttingen Minipig Using Two Input Modes

Objectives: Two novel injury devices were used to characterize impact-induced traumatic brain injury (TBI). One imparts pure translation, and the other produces combined translation and rotation. The objective of this study was to evaluate the neuropathology associated with two injury devices using proton magnetic resonance spectroscopy (1H-MRS) to quantify metabolic changes and immunohistochemistry (IHC) to evaluate axonal damage in the corpus callosum.Methods: Young adult female Göttingen minipigs were exposed to impact-induced TBI with either the translation-input injury device or the combined-input injury device (n = 11/group). Sham animals were treated identically except for the injury event (n = 3). The minipigs underwent 1H-MRS scans prior to injury (baseline), approximately 1 h after injury, and 24 h post injury, at which point the brains were extracted for IHC. Metabolites of interest include glutamate (Glu), glutamine (Gln), N-acetylaspartate (NAA), N-acetylaspartylglutamate (NAAG), and γ-aminobutyric acid (GABA). Repeated measures analysis of variance with a least significant difference post hoc test were used to compare the three time points. IHC was performed on paraffin-embedded sections of the corpus callosum with light and heavy neurofilament antibodies. Stained pixel percentages were compared between shams and 24-h survival animals.Results: For the translation-input group (27.5–70.1 g), 16 significant metabolite differences were found. Three of these include a significant increase in Gln, both 1 h and 24 h postinjury, and an increase in GABA 24 h after injury. For the combined-input group (40.1–95.9 g; 1,014.5–3,814.9 rad/s2; 7.2–10.8 rad/s), 20 significant metabolite differences were found. Three of these include a significant increase in Glu, an increase in the ratio Glu/Gln, and an increase in the ratio Glu/NAAG 24 h after injury. The IHC analysis revealed significant increases in light and heavy neurofilament for both groups 24 h after injury.Conclusions: Only five metabolite differences were similar between the input modes, most of which are related to inflammation or myelin disruption. The observed metabolite differences indicate important dissimilarities. For the translation-input group, an increase in Gln and GABA suggests a response in the GABA shunt system. For the combined-input group, an increase in Glu, Glu/Gln, and Glu/NAAG suggests glutamate excitotoxicity. Importantly, both of these input modes lead to similar light and heavy neurofilament damage, which indicates axonal disruption. Identifying neuropathological changes that are unique to different injury mechanisms is critical in defining the complexity of TBI and can lead to improved prevention strategies and the development of effective drug therapies.

Developmental neurotoxicity of 3,3',4,4'-tetrachloroazobenzene with thyroxine deficit: Sensitivity of glia and dentate granule neurons in the absence of behavioral changes.

Thyroid hormones (TH) regulate biological processes implicated in neurodevelopmental disorders and can be altered with environmental exposures. Developmental exposure to the dioxin-like compound, 3,3’,4,4’-tetrachloroazobenzene (TCAB), induced a dose response deficit in serum T4 levels with no change in 3,5,3’- triiodothyronine or thyroid stimulating hormone. Female Sprague-Dawley rats were orally gavaged (corn oil, 0.1, 1.0, or 10 mg TCAB/kg/day) two weeks prior to cohabitation until post-partum day 3 and male offspring from post-natal day (PND)4-21. At PND21, the high dose showed a deficit in body weight gain. Conventional neuropathology detected no neuronal death, myelin disruption, or gliosis. Astrocytes displayed thinner and less complex processes at 1.0 and 10 mg/kg/day. At 10 mg/kg/day, microglia showed less complex processes, unbiased stereology detected fewer hippocampal CA1 pyramidal neurons and dentate granule neurons (GC) and Golgi staining of the cerebellum showed diminished Purkinje cell dendritic arbor. At PND150, normal maturation of GC number and Purkinje cell branching area was not observed in the 1.0 mg/kg/day dose group with a diminished number and branching suggestive of effects initiated during developmental exposure. No effects were observed on post-weaning behavioral assessments in control, 0.1 and 1.0mg/kg/day dose groups. The demonstrated sensitivity of hippocampal neurons and glial cells to TCAB and T4 deficit raises support for considering additional anatomical features of brain development in future DNT evaluations.

EXOSC8 mutations alter mRNA metabolism and cause hypomyelination with spinal muscular atrophy and cerebellar hypoplasia.

The exosome is a multi-protein complex, required for the degradation of AU-rich element (ARE) containing messenger RNAs (mRNAs). EXOSC8 is an essential protein of the exosome core, as its depletion causes a severe growth defect in yeast. Here we show that homozygous missense mutations in EXOSC8 cause progressive and lethal neurological disease in 22 infants from three independent pedigrees. Affected individuals have cerebellar and corpus callosum hypoplasia, abnormal myelination of the central nervous system or spinal motor neuron disease. Experimental downregulation of EXOSC8 in human oligodendroglia cells and in zebrafish induce a specific increase in ARE mRNAs encoding myelin proteins, showing that the imbalanced supply of myelin proteins causes the disruption of myelin, and explaining the clinical presentation. These findings show the central role of the exosomal pathway in neurodegenerative disease.

Myelin Injury and Degraded Myelin Vesicles in Alzheimer’s Disease

Myelin disruption is an important feature of Alzheimer's disease (AD) that contributes to impairment of neuronal circuitry and cognition. In this study we characterize myelin degradation in the brains of patients with Alzheimer's disease compared with normal aged controls. Myelin from patients with AD (n=13) was compared to matched controls (n=6). Myelin degradation was examined by immunohistochemistry in frontal white matter (WM) for intact myelin basic protein (MBP), degraded MBP, the presence of myelin lipid and for PAS staining. The relationship of myelin degradation and axonal injury was also assessed. Brains from patients with AD had significant loss of intact MBP, and an increase in degraded MBP in periventricular WM adjacent to a denuded ependymal layer. In regions of myelin degradation, vesicles were identified that stained positive for degraded MBP, myelin lipid, and neurofilament but not for intact MBP. Most vesicles stained for PAS, a corpora amylacea marker. The vesicles were significantly more abundant in the periventricular WM of AD patients compared to controls (44.5 ± 11.0 versus 1.7 ± 1.1, p=0.02). In AD patients degraded MBP is associated in part with vesicles particularly in periventricular WM that is adjacent to areas of ependymal injury.

Primary cerebral and cerebellar astrocytes display differential sensitivity to extracellular sodium with significant effects on apoptosis

Central pontine myelinolysis is one of the idiopathic or iatrogenic brain dysfunction, and the most common cause is excessively rapid correction of chronic hyponatraemia. While myelin disruption is the main pathology, as the diagnostic name indicates, a previous study has reported that astrocyte death precedes the destruction of the myelin sheath after the rapid correction of chronic low Na(+) levels, and interestingly, certain brain regions (cerebral cortex, hippocampus, etc.) are specifically damaged but not cerebellum. Here, using primary astrocyte cultures derived from rat cerebral cortex and cerebellum, we examined how extracellular Na(+) alterations affect astrocyte death and whether the response is different between the two populations of astrocytes. Twice the amount of extracellular [Na(+) ] and voltage-gated Na(+) channel opening induced substantial apoptosis in both populations of astrocytes, while, in contrast, one half [Na(+) ] prevented apoptosis in cerebellar astrocytes, in which the Na(+) -Ca(2+) exchanger, NCX2, was highly expressed but not in cerebral astrocytes. Strikingly, the rapid correction of chronic one half [Na(+) ] exposure significantly increased apoptosis in cerebellar astrocytes but not in cerebral astrocytes. These results indicate that extracellular [Na(+) ] affects astrocyte apoptosis, and the response to alterations in [Na(+) ] is dependent on the brain region from which the astrocyte is derived.

Disruption of Myelin Leads to Ectopic Expression of KV1.1 Channels with Abnormal Conductivity of Optic Nerve Axons in a Cuprizone-Induced Model of Demyelination

The molecular determinants of abnormal propagation of action potentials along axons and ectopic conductance in demyelinating diseases of the central nervous system, like multiple sclerosis (MS), are poorly defined. Widespread interruption of myelin occurs in several mouse models of demyelination, rendering them useful for research. Herein, considerable myelin loss is shown in the optic nerves of cuprizone-treated demyelinating mice. Immuno-fluorescence confocal analysis of the expression and distribution of voltage-activated K+ channels (KV1.1 and 1.2 α subunits) revealed their spread from typical juxta-paranodal (JXP) sites to nodes in demyelinated axons, albeit with a disproportionate increase in the level of KV1.1 subunit. Functionally, in contrast to monophasic compound action potentials (CAPs) recorded in controls, responses derived from optic nerves of cuprizone-treated mice displayed initial synchronous waveform followed by a dispersed component. Partial restoration of CAPs by broad spectrum (4-aminopyridine) or KV1.1-subunit selective (dendrotoxin K) blockers of K+ currents suggest enhanced KV1.1-mediated conductance in the demyelinated optic nerve. Biophysical profiling of K+ currents mediated by recombinant channels comprised of different KV1.1 and 1.2 stoichiometries revealed that the enrichment of KV1 channels KV1.1 subunit endows a decrease in the voltage threshold and accelerates the activation kinetics. Together with the morphometric data, these findings provide important clues to a molecular basis for temporal dispersion of CAPs and reduced excitability of demyelinated optic nerves, which could be of potential relevance to the patho-physiology of MS and related disorders.

Evolutive Leukoencephalopathy in Congenital Cytomegalovirus Infection

Congenital cytomegalovirus infection is the most common infectious cause of congenital brain injury. Type and severity of congenital cytomegalovirus infection-related brain abnormalities depend on the developmental stage of the central nervous system at the time of fetal infection. The aim of this study was to follow the course of leukoencephalopathy in a patient with congenital cytomegalovirus infection. We describe brain magnetic resonance imaging (MRI) findings of a boy with symptomatic congenital cytomegalovirus infection performed at the age of 3 weeks, 13 months, and 4 and 7 years. Neonatal brain MRI showed most of characteristic findings in congenital cytomegalovirus infection with most prominent white matter abnormalities and cortical dysplasia. MRI follow-up images showed that cortical dysgenesis remained unchanged and static, whereas white matter abnormalities evolved over the years. We propose that leukoencephalopathy in congenital cytomegalovirus infection is not only nonprogressive or static but even evolutive and suggests both underlying disruption and delay of myelination.

Toll-like receptor 4 gene polymorphism 1196 C/T does not influence the risk of neuropsychiatric systemic lupus erythematosus in Polish population – a preliminary report

Recent data indicate that Toll-like receptors (TLRs) participate in various neuropathologic conditions, including ictogenesis, myelin disruptions associated with chronic alcohol abuse, behavioral and cognitive dysfunctions associated with alcohol-induced neuroinflammatory damage, and activation of microglia to reduce amyloid β deposits. As seizures and depression are well known neuropsychiatric syndromes in systemic lupus erythematosus (SLE) the aim of the study was to investigate whether TLR4 gene polymorphism 1196C/T (rs4986791, Thr399Ile) was a candidate for susceptibility of development of neuropsychiatric systemic lupus erythematosus (NPSLE). The study covered 60 patients with SLE and 100 healthy individuals. TLR4 1196C/T genotyping was performed by real-time polymerase chain reaction with the SimpleProbe. The SLE group comprised 86.7% of patients with wild-type homozygotes CC and 13.3% heterozygotes CT and no homozygotes TT. The control group consisted of 85% wild-type homozygotes CC, 15% heterozygotes CT and no homozygotes TT. The frequencies of genotype and allele distribution in SLE patients did not differ significantly from those of the control subjects. The probability of describing the possible risk of SLE imputed to genotype did not significantly differ in comparison with the healthy individuals (p = 0.77, odds ratio = 0.87, 95% confidence interval 0.34-2.19). A significant genotype association of genotype CC with arthritis was found in SLE patients (p = 0.02). It was further confirmed by a significant association of a dominant allele C with arthritis (p = 0.02). No association between CC and CT genotypes of TLR4 1196C/T and NPSLE was found. Allele distribution of TLR4 1196C/T also was not associated with NPSLE. No other significant differences were found in genotype and allele frequencies regarding clinical manifestation of SLE patients. In the Polish population of SLE patients, 1196C/T polymorphism of TLR4 gene does not increase the risk of development of NPSLE; however, genotype CC and a dominant allele C is associated with arthritis in the course of SLE.

Neuroimmune Activation and Myelin Changes in Adolescent Rats Exposed to High-Dose Alcohol and Associated Cognitive Dysfunction: A Review with Reference to Human Adolescent Drinking

The aim of the study was to assess whether intermittent ethanol administration to adolescent rats activates innate immune response and TLRs signalling causing myelin disruption and long-term cognitive and behavioural deficits. We used a rat model of intermittent binge-like ethanol exposure during adolescence. Binge-like ethanol administration to adolescent rats increased the gene expression of TLR4 and TLR2 in the prefrontal cortex (PFC), as well as inflammatory cytokines TNFα and IL-1β. Up-regulation of TLRs and inflammatory mediators were linked with alterations in the levels of several myelin proteins in the PFC of adolescent rats. These events were associated with previously reported long-term cognitive dysfunctions. Conversely, the same ethanol treatment did not cause significant changes in either inflammatory mediators or myelin changes in the brain of adult rats. Activation of innate immune receptors TLRs in the PFC appears to be involved in the neuroinflammation and demyelination processes induced by ethanol exposure during adolescence. The findings support the vulnerability of the juvenile brain to the effects of ethanol and the long-term cognitive consequences of binge drinking. In addition, ethanol-induced PFC dysfunctions might underlie the propensity of adolescents for impulsivity and to ignore the negative consequences of their behaviour, both of which could increase the risk of substance abuse.

Stem cells for brain repair in neonatal hypoxia–ischemia

Neonatal hypoxic-ischemic insults are a significant cause of pediatric encephalopathy, developmental delays, and spastic cerebral palsy. Although the developing brain's plasticity allows for remarkable self-repair, severe disruption of normal myelination and cortical development upon neonatal brain injury are likely to generate life-persisting sensory-motor and cognitive deficits in the growing child. Currently, no treatments are available that can address the long-term consequences. Thus, regenerative medicine appears as a promising avenue to help restore normal developmental processes in affected infants. Stem cell therapy has proven effective in promoting functional recovery in animal models of neonatal hypoxic-ischemic injury and therefore represents a hopeful therapy for this unmet medical condition. Neural stem cells derived from pluripotent stem cells or fetal tissues as well as umbilical cord blood and mesenchymal stem cells have all shown initial success in improving functional outcomes. However, much still remains to be understood about how those stem cells can safely be administered to infants and what their repair mechanisms in the brain are. In this review, we discuss updated research into pathophysiological mechanisms of neonatal brain injury, the types of stem cell therapies currently being tested in this context, and the potential mechanisms through which exogenous stem cells might interact with and influence the developing brain.