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Microglia belong to tissue-resident macrophages of the central nervous system (CNS), representing the primary innate immune cells. This cell type constitutes ~7% of non-neuronal cells in the mammalian brain and has a variety of biological roles integral to homeostasis and pathophysiology from the late embryonic to adult brain. Its unique identity that distinguishes its "glial" features from tissue-resident macrophages resides in the fact that once entering the CNS, it is perennially exposed to a unique environment following the formation of the blood-brain barrier. Additionally, tissue-resident macrophage progenies derive from various peripheral sites that exhibit hematopoietic potential, and this has resulted in interpretation issues surrounding their origin. Intensive research endeavors have intended to track microglial progenitors during development and disease. The current review provides a corpus of recent evidence in an attempt to disentangle the birthplace of microglia from the progenitor state and underlies the molecular elements that drive microgliogenesis. Furthermore, it caters towards tracking the lineage spatiotemporally during embryonic development and outlining microglial repopulation in the mature CNS. This collection of data can potentially shed light on the therapeutic potential of microglia for CNS perturbations across various levels of severity.
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BACKGROUND: Nerve growth factor (NGF) and its receptors, tropomyosin receptor kinase A (TrkA) and pan-neurotrophin receptor p75 (p75NTR), are known to play bidirectional roles between the immune and nervous system. There are only few studies with inconclusive results concerning the expression pattern and role of NGF, TrkA, and p75NTR (NGF system) under the neuroinflammatory conditions in multiple sclerosis (MS) and its mouse model, the experimental autoimmune encephalomyelitis (EAE). The aim of this study is to investigate the temporal expression in different cell types of NGF system in the central nervous system (CNS) during the EAE course. METHODS: EAE was induced in C57BL/6 mice 6-8 weeks old. CNS tissue samples were collected on specific time points: day 10 (D10), days 20-22 (acute phase), and day 50 (chronic phase), compared to controls. Real-time PCR, Western Blot, histochemistry, and immunofluorescence were performed throughout the disease course for the detection of the spatio-temporal expression of the NGF system. RESULTS: Our findings suggest that both NGF and its receptors, TrkA and p75NTR, are upregulated during acute and chronic phase of the EAE model in the inflammatory lesions in the spinal cord. NGF and its receptors were co-localized with NeuN+ cells, GAP-43+ axons, GFAP+ cells, Arginase1+ cells, and Mac3+ cells. Furthermore, TrkA and p75NTR were sparsely detected on CNPase+ cells within the inflammatory lesion. Of high importance is our observation that despite EAE being a T-mediated disease, only NGF and p75NTR were shown to be expressed by B lymphocytes (B220+ cells) and no expression on T lymphocytes was noticed. CONCLUSION: Our results indicate that the components of the NGF system are subjected to differential regulation during the EAE disease course. The expression pattern of NGF, TrkA, and p75NTR is described in detail, suggesting possible functional roles in neuroprotection, neuroregeneration, and remyelination by direct and indirect effects on the components of the immune system.
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Encefalomielitis Autoinmune Experimental/genética , Regulación de la Expresión Génica/genética , Factor de Crecimiento Nervioso/genética , Receptor trkA/genética , Receptores de Factor de Crecimiento Nervioso/genética , Animales , Linfocitos B/metabolismo , Encéfalo/patología , Encefalomielitis Autoinmune Experimental/metabolismo , Encefalomielitis Autoinmune Experimental/patología , Femenino , Inmunohistoquímica , Ratones , Ratones Endogámicos C57BL , Factor de Crecimiento Nervioso/biosíntesis , Receptor trkA/biosíntesis , Receptores de Factor de Crecimiento Nervioso/biosíntesis , Médula Espinal/metabolismo , Médula Espinal/patología , Linfocitos T/metabolismoRESUMEN
BACKGROUND: Neural precursor cells (NPCs) located in the subventricular zone (SVZ), a well-defined NPC niche, play a crucial role in central nervous system (CNS) homeostasis. Moreover, NPCs are involved in the endogenous reparative process both in multiple sclerosis (MS) and experimental autoimmune encephalomyelitis (EAE). However, the possibility that NPCs may be vulnerable to immune-related components may not be ruled out. Therefore, we investigated the potential affinity of myelin oligodendrocyte glycoprotein (MOG)-induced humoral response(s) to NPCs. METHODS: MOG35-55-EAE was induced in C57BL/6 mice; blood-sampling was performed on days 17-21 (acute phase) along with a naive group and corresponding antisera (AS) were collected (EAE-AS, NAIVE-AS). The presence of anti-CNS autoantibodies was examined with western blotting. Furthermore, using the collected antisera and anti-MOG antibody (as positive control), immunohistochemistry and double immunofluorescence were implemented on normal neonatal, postnatal, and adult mouse brain sections. Targeted NPCs were identified with confocal microscopy. In vitro immunoreactivity assessment on NPCs challenged with autoantibodies was evaluated for apoptotic/autophagic activity. RESULTS: Western blotting verified the existence of autoantibodies in EAE mice and demonstrated bands corresponding to yet unidentified NPC surface epitopes. A dominant selective binding of EAE-AS in the subventricular zone in all age groups compared to NAIVE-AS (p < 0.001) was observed. Additionally, anti-BrdU+/EAE-AS+ colocalization was significantly higher than anti-BrdU+/anti-MOG+, a finding suggesting that the EAE humoral response colocalized with NPCs(BrdU+), cells that do not express MOG. Well-established NPC markers (Nestin, m-Musashi-1, Sox2, DCX, GFAP, NG2) were used to identify the distinct cell types which exhibited selective binding with EAE-AS. The findings verified that EAE-AS exerts cross-reactivity with NPCs which varies throughout the neonatal to adult stage, with a preference to cells of early developmental stages. Finally, increased expressions of Caspase 3 and Beclin 1 on NPCs were detected. CONCLUSION: We provide evidence for the first time that MOG35-55 EAE induces production of antibodies with affinity to SVZ of naive mice in three different age groups. These autoantibodies target lineage-specific NPCs as brain develops and have the potential to trigger apoptotic pathways. Thus, our findings provide indication that cross-talk between immunity and NPCs may lead to functional alteration of NPCs regarding their viability and potentially oligodendrogenesis and effective remyelination.
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Autoanticuerpos/inmunología , Encefalomielitis Autoinmune Experimental/inmunología , Ventrículos Laterales/inmunología , Células-Madre Neurales/inmunología , Animales , Autoantígenos/inmunología , Proteína Doblecortina , Encefalomielitis Autoinmune Experimental/patología , Femenino , Inmunidad Humoral/inmunología , Ventrículos Laterales/patología , Ratones , Ratones Endogámicos C57BL , Glicoproteína Mielina-Oligodendrócito/inmunología , Fragmentos de Péptidos/inmunologíaRESUMEN
BACKGROUND: Nogo-A and its putative receptor NgR are considered to be among the inhibitors of axonal regeneration in the CNS. However, few studies so far have addressed the issue of local NgR complex multilateral localization within inflammation in an MS mouse model of autoimmune demyelination. METHODS: Chronic experimental autoimmune encephalomyelitis (EAE) was induced in C57BL/6 mice. Analyses were performed on acute (days 18-22) and chronic (day 50) time points and compared to controls. The temporal and spatial expression of the Nogo receptor complex (NgR and coreceptors) was studied at the spinal cord using epifluorescent and confocal microscopy or real-time PCR. Data are expressed as cells/mm2, as mean % ± SEM, or as arbitrary units of integrated density. RESULTS: Animals developed a moderate to severe EAE without mortality, followed by a progressive, chronic clinical course. NgR complex spatial expression varied during the main time points of EAE. NgR with coreceptors LINGO-1 and TROY was increased in the spinal cord in the acute phase whereas LINGO-1 and p75 signal seemed to be dominant in the chronic phase, respectively. NgR was detected on gray matter NeuN+ neurons of the spinal cord, within the white matter inflammatory foci (14.2 ± 4.3 % NgR+ inflammatory cells), and found to be colocalized with GAP-43+ axonal growth cones while no ß-TubIII+, SMI-32+, or APP+ axons were found as NgR+. Among the NgR+ inflammatory cells, 75.6 ± 9.0 % were microglial/macrophages (lectin+), 49.6 ± 14.2 % expressed CD68 (phagocytic ED1+ cells), and no cells were Mac-3+. Of these macrophages/monocytes, only Arginase-1+/NgR+ but not iNOS+/NgR+ were present in lesions both in acute and chronic phases. CONCLUSIONS: Our data describe in detail the expression of the Nogo receptor complex within the autoimmune inflammatory foci and suggest a possible immune action for NgR apart from the established inhibitory one on axonal growth. Its expression by inflammatory macrophages/monocytes could signify a possible role of these cells on axonal guidance and clearance of the lesioned area during inflammatory demyelination.
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Sistema Nervioso Central/metabolismo , Sistema Nervioso Central/patología , Encefalomielitis Autoinmune Experimental/patología , Regulación de la Expresión Génica/inmunología , Receptores Nogo/metabolismo , Transducción de Señal/fisiología , Animales , Antígenos de Diferenciación/metabolismo , Arginasa/metabolismo , Modelos Animales de Enfermedad , Encefalomielitis Autoinmune Experimental/inducido químicamente , Encefalomielitis Autoinmune Experimental/complicaciones , Encefalomielitis Autoinmune Experimental/inmunología , Femenino , Adyuvante de Freund/inmunología , Adyuvante de Freund/toxicidad , Regulación de la Expresión Génica/efectos de los fármacos , Ratones , Ratones Endogámicos C57BL , Glicoproteína Mielina-Oligodendrócito/inmunología , Glicoproteína Mielina-Oligodendrócito/toxicidad , Proteínas del Tejido Nervioso/metabolismo , Proteínas Nogo/genética , Proteínas Nogo/metabolismo , Receptores Nogo/genética , Fragmentos de Péptidos/inmunología , Fragmentos de Péptidos/toxicidad , Receptores de Factor de Crecimiento Nervioso/genética , Receptores de Factor de Crecimiento Nervioso/metabolismo , Receptores del Factor de Necrosis Tumoral/genética , Receptores del Factor de Necrosis Tumoral/metabolismo , Transducción de Señal/efectos de los fármacos , Transducción de Señal/inmunología , Estadísticas no ParamétricasRESUMEN
BACKGROUND: Genetic variants appear to influence, at least to some degree, the extent of brain injury and the clinical outcome of patients who have sustained a traumatic brain injury (TBI). Angiotensin-converting enzyme (ACE) is a zinc metallopeptidase that is implicated in the regulation of blood pressure and cerebral circulation. ACE gene polymorphisms were found to regulate serum ACE enzyme activity. OBJECTIVE: The present study aimed to investigate possible influence of ACE gene region variants on patients' outcome after TBI. PATIENTS AND METHODS: In total, 363 TBI patients prospectively enrolled in the study were genotyped for five tag single nucleotide polymorphisms (SNPs) across the ACE gene. Using logistic regression analyses, tag SNPs and their constructed haplotypes were tested for associations with 6-month Glasgow Outcome Scale scores, after adjustment for age, sex, Glasgow Coma Scale scores at admission, and the presence of a hemorrhagic event in the initial computed tomography scan. RESULTS: Significant effects on TBI outcome were found for three neighboring tag SNPs in the codominant (genotypic) model of inheritance [rs4461142: odds ratio (OR) 0.26, 95% confidence interval (CI) 0.12-0.57, P = 0.0001; rs7221780: OR 2.67, 95% CI 1.25-5.72, P = 0.0003; and rs8066276: OR 3.82, 95% CI 1.80-8.13, P = 0.0002; for the heterozygous variants compared with the common alleles]. None of the constructed common tag SNPs haplotypes was associated with TBI outcome. CONCLUSION: The present study provides evidence of the possible influence of genetic variations in a specific region of the ACE gene on the outcome of TBI patients. This association may have pharmacogenetic implications in identifying those TBI patients who may benefit from ACE inhibition.
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Lesiones Encefálicas/genética , Peptidil-Dipeptidasa A/genética , Polimorfismo de Nucleótido Simple/genética , Adolescente , Adulto , Anciano , Anciano de 80 o más Años , Alelos , Demografía , Femenino , Frecuencia de los Genes/genética , Sitios Genéticos , Escala de Coma de Glasgow , Haplotipos , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Resultado del Tratamiento , Adulto JovenRESUMEN
In multiple sclerosis (MS), diffuse degenerative processes in the deep grey matter have been associated with clinical disabilities. We performed a systematic study in MS deep grey matter with a focus on the incidence and topographical distribution of lesions in relation to white matter and cortex in a total sample of 75 MS autopsy patients and 12 controls. In addition, detailed analyses of inflammation, acute axonal injury, iron deposition and oxidative stress were performed. MS deep grey matter was affected by two different processes: the formation of focal demyelinating lesions and diffuse neurodegeneration. Deep grey matter demyelination was most prominent in the caudate nucleus and hypothalamus and could already be seen in early MS stages. Lesions developed on the background of inflammation. Deep grey matter inflammation was intermediate between low inflammatory cortical lesions and active white matter lesions. Demyelination and neurodegeneration were associated with oxidative injury. Iron was stored primarily within oligodendrocytes and myelin fibres and released upon demyelination. In addition to focal demyelinated plaques, the MS deep grey matter also showed diffuse and global neurodegeneration. This was reflected by a global reduction of neuronal density, the presence of acutely injured axons, and the accumulation of oxidised phospholipids and DNA in neurons, oligodendrocytes and axons. Neurodegeneration was associated with T cell infiltration, expression of inducible nitric oxide synthase in microglia and profound accumulation of iron. Thus, both focal lesions as well as diffuse neurodegeneration in the deep grey matter appeared to contribute to the neurological disabilities of MS patients.
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Enfermedades Desmielinizantes/patología , Sustancia Gris/patología , Inflamación/patología , Hierro/química , Esclerosis Múltiple/patología , Adulto , Anciano , Anciano de 80 o más Años , Encéfalo/patología , Química Encefálica , Estudios de Casos y Controles , Núcleo Caudado/patología , Progresión de la Enfermedad , Femenino , Humanos , Hipotálamo/patología , Masculino , Persona de Mediana Edad , Estudios Retrospectivos , Sustancia Blanca/patologíaRESUMEN
Stress-related mental disorders have become increasingly prevalent, thus endangering mental health worldwide. Exploring stress-associated brain alterations is vital for understanding the possible neurobiological mechanisms underlying these changes. Based on existing evidence, the brain endogenous cannabinoid system (ECS) plays a significant role in the stress response, and disruptions in its function are associated with the neurobiology of various stress-related disorders. This study primarily focuses on investigating the impact of chronic unpredictable stress (CUS) on the expression of hippocampal cannabinoid type 1 (CB1) receptors, part of the ECS, in adult male and female Wistar rats. Additionally, it explores whether environmental enrichment (EE) initiated during adolescence could mitigate the CUS-associated alterations in CB1 expression. Wistar rats, shortly after weaning, were placed in either standard housing (SH) or EE conditions for a duration of 10 weeks. On postnatal day 66, specific subgroups of SH or EE animals underwent a 4-week CUS protocol. Western blot (WB) analysis was conducted in the whole hippocampus of the left brain hemisphere to assess total CB1 protein expression, while immunohistochemistry (IHC) was performed on the right hemisphere to estimate the expression of CB1 receptors in certain hippocampal areas (i.e., CA1, CA3 and dentate gyrus-DG). The WB analysis revealed no statistically significant differences in total CB1 protein levels among the groups; however, reduced CB1 expression was found in specific hippocampal sub-regions using IHC. Specifically, CUS significantly decreased CB1 receptor expression in the CA1 and DG of both sexes, whereas in CA3 the CUS-associated decrease was limited to SH males. Interestingly, EE housing proved protective against these reductions. These findings suggest a region and sex-specific endocannabinoid response to chronic stress, emphasizing the role of positive early experiences in the protection of the adolescent brain against adverse conditions later in life.
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The process of ageing is characteristic of multicellular organisms associated with late stages of the lifecycle and is manifested through a plethora of phenotypes. Its underlying mechanisms are correlated with age-dependent diseases, especially neurodegenerative diseases such as Alzheimer's disease (AD), Parkinson's disease (PD) and multiple sclerosis (MS) that are accompanied by social and financial difficulties for patients. Over time, people not only become more prone to neurodegeneration but they also lose the ability to trigger pivotal restorative mechanisms. In this review, we attempt to present the already known molecular and cellular hallmarks that characterize ageing in association with their impact on the central nervous system (CNS)'s structure and function intensifying possible preexisting pathogenetic conditions. A thorough and elucidative study of the underlying mechanisms of ageing will be able to contribute further to the development of new therapeutic interventions to effectively treat age-dependent manifestations of neurodegenerative diseases.
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BACKGROUND: It is well known that axotomy in the neonatal period causes massive loss of motoneurons, which is reflected in the reduction of the number of motor units and the alteration in muscle properties. This type of neuronal death is attributed to the excessive activation of the ionotropic glutamate receptors (glutamate excitotoxicity). In the present study we investigated the effect of the NMDA antagonist DAP5 [D-2-amino-5-phosphonopentanoic acid] in systemic administration, on muscle properties and on behavioural aspects following peripheral nerve injury. METHODS: Wistar rats were subjected to sciatic nerve crush on the second postnatal day. Four experimental groups were included in this study: a) controls (injection of 0.9% NaCl solution) b) crush c) DAP5 treated and d) crush and DAP5 treated. Animals were examined with isometric tension recordings of the fast extensor digitorum longus and the slow soleus muscles, as well as with locomotor tests at four time points, at P14, P21, P28 and adulthood (2 months). RESULTS: 1. Administration of DAP5 alone provoked no apparent adverse effects. 2. In all age groups, animals with crush developed significantly less tension than the controls in both muscles and had a worse performance in locomotor tests (p < 0.01). Crush animals injected with DAP5 were definitely improved as their tension recordings and their locomotor behaviour were significantly improved compared to axotomized ones (p < 0.01). 3. The time course of soleus contraction was not altered by axotomy and the muscle remained slow-contracting in all developmental stages in all experimental groups. EDL, on the other hand, became slower after the crush (p < 0.05). DAP5 administration restored the contraction velocity, even up to the level of control animals 4. Following crush, EDL becomes fatigue resistant after P21 (p < 0.01). Soleus, on the other hand, becomes less fatigue resistant. DAP5 restored the profile in both muscles. CONCLUSIONS: Our results confirm that contractile properties and locomotor behaviour of animals are severely affected by axotomy, with a differential impact on fast contracting muscles. Administration of DAP5 reverses these devastating effects, without any observable side-effects. This agent could possibly show a therapeutic potential in other models of excitotoxic injury as well.
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2-Amino-5-fosfonovalerato/farmacología , Antagonistas de Aminoácidos Excitadores/farmacología , Neuronas Motoras/efectos de los fármacos , Movimiento/efectos de los fármacos , Contracción Muscular/efectos de los fármacos , Músculo Esquelético/efectos de los fármacos , N-Metilaspartato/antagonistas & inhibidores , Animales , Animales Recién Nacidos , Axotomía/métodos , Conducta Animal , Femenino , Masculino , Neuronas Motoras/fisiología , Movimiento/fisiología , Contracción Muscular/fisiología , Desnervación Muscular/métodos , Compresión Nerviosa/métodos , Ratas WistarRESUMEN
The localization of bacterial components and/or metabolites in the central nervous system may elicit neuroinflammation and/or neurodegeneration. Helicobacter pylori (a non-commensal symbiotic gastrointestinal pathogen) infection and its related metabolic syndrome have been implicated in the pathogenesis of gastrointestinal tract and central nervous system disorders, thus medications affecting the nervous system - gastrointestinal tract may shape the potential of Helicobacter pylori infection to trigger these pathologies. Helicobacter pylori associated metabolic syndrome, by impairing gut motility and promoting bacterial overgrowth and translocation, might lead to brain pathologies. Trimebutine maleate is a prokinetic drug that hastens gastric emptying, by inducing the release of gastrointestinal agents such as motilin and gastrin. Likewise, it appears to protect against inflammatory signal pathways, involved in inflammatory disorders including brain pathologies. Trimebutine maleate also acts as an antimicrobial agent and exerts opioid agonist effect. This study aimed to investigate a hypothesis regarding the recent advances in exploring the potential role of gastrointestinal tract microbiota dysbiosis-related metabolic syndrome and Helicobacter pylori in the pathogenesis of gastrointestinal tract and brain diseases. We hereby proposed a possible neuroprotective role for trimebutine maleate by altering the dynamics of the gut-brain axis interaction, thus suggesting an additional effect of trimebutine maleate on Helicobacter pylori eradication regimens against these pathologies.
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Encefalopatías/tratamiento farmacológico , Fármacos Gastrointestinales/uso terapéutico , Enfermedades Gastrointestinales/tratamiento farmacológico , Infecciones por Helicobacter/tratamiento farmacológico , Helicobacter pylori/efectos de los fármacos , Trimebutino/uso terapéutico , Encefalopatías/epidemiología , Encefalopatías/fisiopatología , Disbiosis/tratamiento farmacológico , Disbiosis/epidemiología , Disbiosis/fisiopatología , Fármacos Gastrointestinales/farmacología , Enfermedades Gastrointestinales/epidemiología , Enfermedades Gastrointestinales/fisiopatología , Microbioma Gastrointestinal/efectos de los fármacos , Microbioma Gastrointestinal/fisiología , Infecciones por Helicobacter/epidemiología , Infecciones por Helicobacter/fisiopatología , Helicobacter pylori/fisiología , Humanos , Resultado del Tratamiento , Trimebutino/farmacologíaRESUMEN
Despite efforts aimed at developing novel therapeutics for traumatic brain injury (TBI), no specific pharmacological agent is currently clinically available. Here, we show that the pan-histone deacetylase (HDAC) inhibitor ITF2357, a compound shown to be safe and effective in humans, improves functional recovery and attenuates tissue damage when administered as late as 24 h postinjury. Using a well-characterized, clinically relevant mouse model of closed head injury (CHI), we demonstrate that a single dose of ITF2357 administered 24 h postinjury improves neurobehavioral recovery from d 6 up to 14 d postinjury (improved neurological score vs. vehicle; P< or =0.05), and that this functional benefit is accompanied by decreased neuronal degeneration, reduced lesion volume (22% reduction vs. vehicle; P< or =0.01), and is preceded by increased acetylated histone H3 levels and attenuation of injury-induced decreases in cytoprotective heat-shock protein 70 kDa and phosphorylated Akt. Moreover, reduced glial accumulation and activation were observed 3 d postinjury, and total p53 levels at the area of injury and caspase-3 immunoreactivity within microglia/macrophages at the trauma area were elevated, suggesting enhanced clearance of these cells via apoptosis following treatment. Hence, our findings underscore the relevance of HDAC inhibitors for ameliorating trauma-induced functional deficits and warrant consideration of applying ITF2357 for this indication.
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Apoptosis/efectos de los fármacos , Lesiones Encefálicas/tratamiento farmacológico , Histona Desacetilasas/metabolismo , Ácidos Hidroxámicos/farmacología , Neuroglía/efectos de los fármacos , Animales , Encéfalo/patología , Caspasa 3/metabolismo , Ácidos Hidroxámicos/administración & dosificación , Masculino , Ratones , Fármacos Neuroprotectores/farmacologíaRESUMEN
Both heat acclimation (HA) and post-injury treatment with recombinant human erythropoietin (Epo, rhEpo, exogenous Epo) are neuroprotective against traumatic brain injury (TBI). Our previous data demonstrated that HA-induced neuroprotection includes improved functional recovery and reduced cerebral edema formation. Additionally, in earlier Western-blot analyses, we found that HA mice display increased expression of the specific erythropoietin receptor (EpoR) and of hypoxia-inducible factor-1 alpha (HIF-1 alpha), the inducible subunit of the transcription factor, which regulates Epo gene expression, but not of Epo itself. In light of this, the aim of the current study was threefold: (1) to assess Epo expression in the trauma area and hippocampus following HA, rhEpo administration, or combined HA-rhEpo treatment, using immunohistochemical methods that offer enhanced anatomical resolution; (2) to examine the effects of endogenous and exogenous Epo on edema formation in normothermic (NT) mice; and (3) to evaluate the effects of exogenous Epo administration on neuroprotective outcome measures in HA animals. HA induced enhanced expression of endogenous Epo in the trauma area and the hippocampus. Treatment with anti-Epo antibody given to NT mice increased edema formation, whereas rhEpo induced no beneficial effect. Cognitive performance testing and immunohistochemical findings reinforced HA and rhEpo as separate protective interventions but showed no advantage to combining the two strategies. We therefore suggest that HA-induced neuroprotection is shaped by pre-existing mediators but cannot be modified by post-injury treatment aimed at increasing the levels of neuroprotective agents.
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Lesiones Encefálicas/tratamiento farmacológico , Eritropoyetina/farmacología , Eritropoyetina/fisiología , Fármacos Neuroprotectores , Aclimatación , Animales , Edema Encefálico/etiología , Edema Encefálico/prevención & control , Lesiones Encefálicas/patología , Cognición/fisiología , Eritropoyetina/biosíntesis , Eritropoyetina/uso terapéutico , Fluoresceínas , Colorantes Fluorescentes , Hipocampo/patología , Calor , Humanos , Inmunohistoquímica , Inmunoterapia , Masculino , Ratones , Degeneración Nerviosa/patología , Compuestos Orgánicos , Reconocimiento en Psicología/fisiología , Proteínas RecombinantesRESUMEN
Traumatic brain injury triggers a massive glutamate efflux, activation of NMDA receptor channels, and cell death. Recently, we reported that NMDA receptors in mice are down-regulated from hours to days following closed head injury (CHI), and treatment with NMDA improved recovery of motor and cognitive functions up to 14 d post-injury. Here we show that a single injection of a low dose of D-cycloserine (DCS), a partial NMDA receptor agonist, in CHI mice 24 h post-injury, resulted in a faster and greater recovery of motor and memory functions as assessed by neurological severity score and object recognition tests, respectively. Moreover, DCS treatment of CHI mice led to a significant improvement of hippocampal long-term potentiation (LTP) in the CA1 region that was completely blunted in CHI control mice. However, DCS did not improve CHI-induced impairment in synaptic glutamate release measured by paired pulse facilitation (PPF) ratio in hippocampal CA1 region. Finally, CHI-induced reduction of brain-derived neurotrophic factor (BDNF) was fully restored following DCS treatment. Since DCS is in clinical use for other indications, the present study offers a novel approach to treat human brain injury.
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Lesiones Encefálicas/tratamiento farmacológico , Cicloserina/uso terapéutico , Agonistas de Aminoácidos Excitadores/uso terapéutico , Traumatismos Cerrados de la Cabeza/complicaciones , Potenciación a Largo Plazo/efectos de los fármacos , Fármacos Neuroprotectores/uso terapéutico , Receptores de N-Metil-D-Aspartato/agonistas , Animales , Astrocitos/metabolismo , Astrocitos/patología , Lesiones Encefálicas/etiología , Lesiones Encefálicas/fisiopatología , Factor Neurotrófico Derivado del Encéfalo/biosíntesis , Factor Neurotrófico Derivado del Encéfalo/genética , Cicloserina/farmacología , Evaluación Preclínica de Medicamentos , Agonistas de Aminoácidos Excitadores/farmacología , Potenciales Postsinápticos Excitadores/efectos de los fármacos , Hipocampo/efectos de los fármacos , Hipocampo/fisiopatología , Hipocampo/ultraestructura , Masculino , Ratones , Microglía/metabolismo , Microglía/patología , Actividad Motora/efectos de los fármacos , Fármacos Neuroprotectores/farmacología , Receptores de N-Metil-D-Aspartato/fisiología , Reconocimiento en Psicología/efectos de los fármacos , Método Simple Ciego , Sinaptofisina/biosíntesis , Sinaptofisina/genéticaRESUMEN
Exposure to environmental enrichment can beneficially influence the behavior and enhance synaptic plasticity. The aim of the present study was to investigate the mediated effects of environmental enrichment on postnatal stress-associated impact with regard to behavior, stress reactivity as well as synaptic plasticity changes in the dorsal hippocampus. Wistar rat pups were submitted to a 3â¯h maternal separation (MS) protocol during postnatal days 1-21, while another group was left undisturbed. On postnatal day 23, a subgroup from each rearing condition (maternal separation, no-maternal separation) was housed in enriched environmental conditions until postnatal day 65 (6 weeks duration). At approximately three months of age, adult rats underwent behavioral testing to evaluate anxiety (Elevated Plus Maze), locomotion (Open Field Test), spatial learning and memory (Morris Water Maze) as well as non-spatial recognition memory (Novel Object Recognition Test). After completion of behavioral testing, blood samples were taken for evaluation of stress-induced plasma corticosterone using an enzyme-linked immunosorbent assay (ELISA), while immunofluorescence was applied to evaluate hippocampal BDNF and synaptophysin expression in dorsal hippocampus. We found that environmental enrichment protected against the effects of maternal separation as indicated by the lower anxiety levels and the reversal of spatial memory deficits compared to animals housed in standard conditions. These changes were associated with increased BDNF and synaptophysin expression in the hippocampus. Regarding the neuroendocrine response to stress, while exposure to an acute stressor potentiated corticosterone increases in maternally-separated rats, environmental enrichment of these rats prevented this effect. The current study aimed at investigating the compensatory role of enriched environment against the negative outcomes of adverse experiences early in life concurrently on emotional and cognitive behaviors, HPA function and neuroplasticity markers.
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Factor Neurotrófico Derivado del Encéfalo/metabolismo , Ambiente , Regulación de la Expresión Génica/fisiología , Hipocampo/metabolismo , Estrés Psicológico/enfermería , Sinaptofisina/metabolismo , Animales , Animales Recién Nacidos , Peso Corporal/fisiología , Corticosterona/sangre , Conducta Exploratoria/fisiología , Femenino , Masculino , Privación Materna , Aprendizaje por Laberinto/fisiología , Ratas , Ratas Wistar , Reconocimiento en Psicología , Estrés Psicológico/sangre , Estrés Psicológico/patología , Estrés Psicológico/fisiopatologíaRESUMEN
Α limited number of genetic variants have been linked to the development of intracerebral hemorrhage (ICH). Ιntegrin AV and/or B8-deficient mice were found to develop ICH. The present candidate gene association study was designed to investigate possible influence of integrin AV (ITGAV) and integrin B8 (ITGB8) gene region polymorphisms on the risk of ICH. 1015 participants (250 Greek and 193 Polish patients with primary ICH and 250 Greek and 322 Polish controls) were included in the study. Using logistic regression analyses, 11 tag single nucleotide polymorphisms (SNPs) for ITGAV and 11 for ITGB8 gene were tested for associations with ICH risk, lobar ICH risk and non-lobar ICH after adjustment for age, gender, history of hypertension and country of origin. Linear regression models were used to test the effect of tag SNPs on the ICH age of onset. Correction for multiple comparisons was carried out. The rs7565633 tag SNP of the ITGAV gene was independently associated with the risk of lobar ICH in the codominant model of inheritance [odds ratio (95 % confidence interval (CI)) 0.56 (0.36-0.86), p = 0.0013]. Furthermore, heterozygous individuals of the rs10251386 and the rs10239099 of the ITGB8 gene had significantly lower age of ICH onset compared to the wild-type genotypes [regression coefficient (b) -3.884 (95 % CI -6.519, -1.249), p = 0.0039 and b = -4.502 (95 % CI -7.159, -1.845), p = 0.0009, respectively]. The present study provides preliminary indication for an influence of ITGAV gene tag SNP in the development of lobar ICH and of ITGB8 gene variants in the age of ICH onset.
Asunto(s)
Hemorragia Cerebral/genética , Integrina alfaV/genética , Cadenas beta de Integrinas/genética , Polimorfismo de Nucleótido Simple , Edad de Inicio , Anciano , Anciano de 80 o más Años , Estudios de Casos y Controles , Corteza Cerebral/irrigación sanguínea , Hemorragia Cerebral/etnología , Femenino , Frecuencia de los Genes , Predisposición Genética a la Enfermedad , Genotipo , Grecia/epidemiología , Humanos , Masculino , Persona de Mediana Edad , Polonia/epidemiología , Factores de RiesgoRESUMEN
Increasing evidence shows that exposure to an enriched environment (EE) is neuroprotective in adult and neonatal animal models of brain ischemia. However, the mechanisms underlying this effect remain unclear. The aim of the current study was to investigate whether post-weaning EE would be effective in preventing functional deficits and brain damage by affecting markers of synaptic plasticity in a neonatal rat model of hypoxia-ischemia (HI). We also examined the possibility that granulocyte-colony stimulating factor (G-CSF), a growth factor with known neuroprotective effects in a variety of experimental brain injury models, combined with EE stimulation could enhance the potential beneficial effect of EE. Seven-day-old Wistar rats of either sex were subjected to permanent ligation of the left common carotid artery followed by 60min of hypoxia (8% O2) and immediately after weaning (postnatal day 21) were housed in enriched conditions for 4weeks. A group of enriched-housed rats had been treated with G-CSF immediately after HI for 5 consecutive days (50µg/kg/day). Behavioral examination took place approximately at three months of age and included assessments of learning and memory (Morris water maze) as well as motor coordination (Rota-Rod). Infarct size and hippocampal area were estimated following behavioral assessment. Synaptic plasticity was evaluated based on BDNF and synaptophysin expression in the dorsal hippocampus. EE resulted in recovery of post-HI motor deficits and partial improvement of memory impairments which was not accompanied by reduced brain damage. Increased synaptophysin expression was observed in the contralateral to carotid ligation hemisphere. Hypoxia-ischemia alone or followed by enriched conditions did not affect BDNF expression which was increased only in enriched-housed normal rats. The combined therapy of G-CSF and EE further enhanced cognitive function compared to EE provided as monotherapy and prevented HI-induced brain damage by altering synaptic plasticity as reflected by increased synaptophysin expression. The above findings demonstrate that combination of neuroprotective treatments may result in increased protection and it might be a more effective strategy for the treatment of neonatal hypoxic-ischemic brain injury.
Asunto(s)
Ambiente , Factor Estimulante de Colonias de Granulocitos/farmacología , Hipocampo/metabolismo , Hipoxia-Isquemia Encefálica/metabolismo , Hipoxia-Isquemia Encefálica/terapia , Fármacos Neuroprotectores/farmacología , Animales , Animales Recién Nacidos , Asfixia Neonatal/metabolismo , Asfixia Neonatal/patología , Asfixia Neonatal/terapia , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Terapia Combinada , Modelos Animales de Enfermedad , Hipocampo/efectos de los fármacos , Hipocampo/patología , Vivienda para Animales , Hipoxia-Isquemia Encefálica/patología , Aprendizaje por Laberinto/efectos de los fármacos , Aprendizaje por Laberinto/fisiología , Memoria a Corto Plazo/efectos de los fármacos , Memoria a Corto Plazo/fisiología , Actividad Motora/efectos de los fármacos , Actividad Motora/fisiología , Distribución Aleatoria , Ratas Wistar , Memoria Espacial/efectos de los fármacos , Memoria Espacial/fisiología , Sinaptofisina/metabolismoRESUMEN
Superoxide-dismutases (SOD) catalyze O2- conversion to hydrogen peroxide (H2O2) and with other antioxidant enzymes and low molecular weight antioxidants (LMWA) constitute endogenous defense mechanisms. We first assessed the effects of SOD1 levels on outcome after closed head injury (CHI) and later, based on these results, the effects of SOD1 deficiency on cellular redox homeostasis. Superoxide-dismutase 1-deficient (SOD1-/-) and -overexpressing (transgenic (Tg)) mice and matched wild-type (WT) controls were subjected to CHI and outcome (neurobehavioral and memory functions) was assessed during 14 days. Brain edema, LMWA, and SOD2 activity were measured along with histopathological analysis. Transactivation of nuclear factor-kappa B (NF-kappaB) was evaluated by electromobility shift assay. Mortality, motor, and cognitive outcome of Tg and WT mice were comparable. Mortality and edema were similar in SOD1-/- and WT mice, yet, unexpectedly, SOD1-/- displayed better neurobehavioral recovery (P<0.05) at 14 days after CHI. Basal LMWA were higher in the cortex and liver of SOD1-/- mice (P<0.05) and similar to WT in the cerebellum. Five minutes after CHI, cortical LMWA decreased only in SOD1-/- mice. One week after CHI, SOD2 activity decreased fourfold in WT cortex (P<0.001), but was preserved in the SOD1-/-. Constitutive NF-kappaB transactivation was comparably low in SOD1-/- and WT; however, CHI induced a robust NF-kappaB activation that was absent in SOD1-/- cortices (P<0.005 versus WT). At the same time, immunohistochemical analysis of brain sections revealed that astrogliosis and neurodegeneration were of lesser severity in SOD1-/- mice. We suggest that SOD1 deficiency impairs H2O2-mediated activation of NF-kappaB, decreasing death-promoting signals, and leading to better outcome.
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Lesiones Encefálicas/metabolismo , FN-kappa B/metabolismo , Superóxido Dismutasa/deficiencia , Cicatrización de Heridas , Animales , Antioxidantes/análisis , Edema Encefálico/etiología , Lesiones Encefálicas/fisiopatología , Cognición , Homeostasis , Humanos , Inmunohistoquímica , Masculino , Ratones , Ratones Transgénicos , Actividad Motora , Oxidación-Reducción , Superóxido Dismutasa/análisis , Superóxido Dismutasa/genética , Tasa de SupervivenciaRESUMEN
Exposure to early-life stress is associated with long-term alterations in brain and behavior, and may aggravate the outcome of neurological insults. This study aimed at investigating the possible interaction between maternal separation, a model of early stress, and subsequent neonatal hypoxia-ischemia on emotional behavior and markers of synaptic plasticity in hippocampus. Therefore, rat pups (N=60) were maternally separated for a prolonged (MS 180min) or a brief (MS 15min) period during the first six postnatal days, while a control group was left undisturbed. Hypoxia-ischemia was applied to a subgroup of each rearing condition on postnatal day 7. Emotional behavior was examined at three months of age and included assessments of anxiety (elevated plus maze), depression-like behavior (forced swimming) and spontaneous exploration (open field). Synaptic plasticity was evaluated based on BDNF and synaptophysin expression in CA3 and dentate gyrus hippocampal regions. We found that neonatal hypoxia-ischemia caused increased levels of anxiety, depression-like behavior and locomotor activity (ambulation). Higher anxiety levels were also seen in maternally separated rats (MS180min) compared to non-maternally separated rats, but prolonged maternal separation prior to HI did not potentiate the HI-associated effect. No differences among the three rearing conditions were found regarding depression-like behavior or ambulation. Immunohistochemical evaluation of synaptophysin revealed that both prolonged maternal separation (MS180min) and neonatal hypoxia-ischemia significantly reduced its expression in the CA3 and dentate gyrus. Decreases in synaptophysin expression in these areas were not exacerbated in rats that were maternally separated for a prolonged period prior to HI. Regarding BDNF expression, we found a significant decrease in immunoreactivity only in the hypoxic-ischemic rats that were subjected to the prolonged maternal separation paradigm. The above findings suggest that early-life stress prior to neonatal hypoxia-ischemia leads to significant alterations in synaptic plasticity of the dorsal hippocampus during adulthood, but does not exacerbate HI-related changes in emotional behavior.
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Hipocampo/fisiopatología , Hipoxia/complicaciones , Privación Materna , Plasticidad Neuronal/fisiología , Estrés Psicológico/etiología , Estrés Psicológico/patología , Factores de Edad , Análisis de Varianza , Animales , Animales Recién Nacidos , Factor Neurotrófico Derivado del Encéfalo/metabolismo , Conducta Exploratoria/fisiología , Femenino , Hipocampo/patología , Masculino , Aprendizaje por Laberinto/fisiología , Ratas , Ratas Wistar , Natación/psicología , Sinaptofisina/metabolismo , Factores de TiempoRESUMEN
Perinatal asphyxia accounts for behavioral dysfunctions that often manifest as sensorimotor, learning or memory disabilities throughout development and into maturity. Erythropoietin (Epo) has been shown to exert neuroprotective effects in different models of brain injury including experimental models of perinatal asphyxia. However, the effect of Epo on functional abilities following cerebral hypoxia-ischemia (HI) in neonatal rats is not known. The aim of the present study is to investigate the effect of Epo on sensorimotor deficits and brain injury induced by hypoxia-ischemia. Seven-day-old rats underwent unilateral, permanent carotid artery ligation followed by 1 h of hypoxia. Epo was administered as a single dose immediately after the hypoxic insult (2000 U/kg). The neuroprotective effect of Epo was evaluated at postnatal day 42 by using a battery of behavioral tests and histological analysis. The results of the present study suggest that Epo treatment immediately after HI insult significantly facilitated recovery of sensorimotor function. Consistently, histopathological evaluation demonstrated that Epo significantly attenuated brain injury and preserved the integrity of cerebral cortex. These findings indicate that long-term neuroprotective effect of Epo on neonatal HI-induced brain injury might be associated with the preservation of sensorimotor functions.
Asunto(s)
Infarto Cerebral/tratamiento farmacológico , Eritropoyetina/farmacología , Hipoxia-Isquemia Encefálica/tratamiento farmacológico , Fármacos Neuroprotectores/farmacología , Animales , Animales Recién Nacidos , Corteza Cerebral/efectos de los fármacos , Corteza Cerebral/patología , Corteza Cerebral/fisiopatología , Infarto Cerebral/fisiopatología , Infarto Cerebral/prevención & control , Modelos Animales de Enfermedad , Eritropoyetina/uso terapéutico , Femenino , Humanos , Hipoxia-Isquemia Encefálica/fisiopatología , Hipoxia-Isquemia Encefálica/prevención & control , Ligadura , Masculino , Trastornos del Movimiento/etiología , Trastornos del Movimiento/fisiopatología , Trastornos del Movimiento/prevención & control , Fármacos Neuroprotectores/uso terapéutico , Ratas , Ratas Wistar , Recuperación de la Función/efectos de los fármacos , Recuperación de la Función/fisiología , Trastornos de la Sensación/etiología , Trastornos de la Sensación/fisiopatología , Trastornos de la Sensación/prevención & control , Resultado del TratamientoRESUMEN
Animal studies suggest that maternal separation, a widely used paradigm to study the effects of early life adversity, exerts a profound and life-long impact on both brain and behavior. The aim of the current study was to investigate whether adverse early life experiences interact with neonatal hypoxia-ischemia, affecting the outcome of this neurological insult at both functional and structural levels during adulthood. Rat pups were separated from their mothers during postnatal days 1-6, for either a short (15 min) or prolonged (180 min) period, while another group was left undisturbed. On postnatal day 7, a subgroup from each of the three postnatal manipulations was exposed to a hypoxic-ischemic episode. Behavioral examination took place approximately at three months of age and included tests of learning and memory (Morris water maze, novel object and novel place recognition), as well as motor coordination (rota-rod). We found that both prolonged maternal separation and neonatal hypoxia-ischemia impaired the animals' spatial learning and reference memory. Deficits in spatial but not visual recognition memory were detected only in hypoxic-ischemic rats. Interestingly, prolonged maternal separation prior to neonatal hypoxia-ischemia augmented the reference memory impairments. Histological analysis of infarct size, hippocampal area and thickness of corpus callosum did not reveal any exacerbation of damage in hypoxic-ischemic rats that were maternally separated for a prolonged period. These are the first data suggesting that an adverse postnatal environmental manipulation of just 6 days causes long-term effects on spatial learning and memory and may render the organism more vulnerable to a subsequent insult.