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OBJECTIVE: This study aims to assess the clinical, inflammatory, and genetic profiles of traumatic brain injury (TBI) patients over a 2-year follow-up period, focusing on the development of posttraumatic epilepsy (PTE). METHODS: Fifty-nine patients with acute TBI were recruited in the emergency unit of a hospital in Brazil. Clinical data and blood samples were collected after 10 days of hospitalization for posterior genetic profile (Apolipoprotein E- ApoE and Glutamic Acid Descarboxylase-GAD sequencing) analyses. A subset of 19 patients were assessed for cytokine markers (mRNA expression). The development of PTE was investigated for two years following TBI. Statistical analyses including univariate analysis, multiple correspondence analysis, and Mann-Whitney test were performed. RESULTS: Analysis revealed an association between severe TBI and requirement for neurosurgery and polytrauma (p<0.05), as well as the development of PTE over a two-year follow-up period (p<0.05). Multiple correspondence analysis identified two distinct profiles associated with PTE and Non-PTE outcomes. The PTE profile showed a higher prevalence of the ApoE genotype E3/E3 and GAD1 SNP (rs769391) genotype AA in our study, while the Non-PTE profile showed a higher presence of E3/E4. mRNA expression analysis demonstrated acute elevated levels of TNF-α in the PTE group as compared to Non-PTE patients (6.70±1.53 vs 5.31 ±0.33, p<0.01). SIGNIFICANCE: Our findings underscore the multifactorial nature of aspects potentially contributing to PTE. It is unlikely that any single factor might in isolation have a strong causative influence over the development of epilepsy after TBI. Our results provide a suggestion of potential clustering that might be relevant as prognostic factors for PTE.
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Lesões Encefálicas Traumáticas , Epilepsia Pós-Traumática , Humanos , Lesões Encefálicas Traumáticas/genética , Lesões Encefálicas Traumáticas/complicações , Masculino , Feminino , Epilepsia Pós-Traumática/genética , Epilepsia Pós-Traumática/etiologia , Adulto , Pessoa de Meia-Idade , Apolipoproteínas E/genética , Adulto Jovem , Seguimentos , Genótipo , Inflamação/genética , Brasil/epidemiologia , Citocinas/sangue , Citocinas/genética , Polimorfismo de Nucleotídeo Único/genéticaRESUMO
BACKGROUND: Cytokines and chemokines play an important role in the neuroinflammatory response to an initial precipitating injury such as status epilepticus (SE). These signaling molecules participate in recruitment of immune cells, including brain macrophages (microglia), as well as neuroplastic changes, deterioration of damaged tissue, and epileptogenesis. This study describes the temporal and brain region pattern expression of numerous cytokines, including chemokines, after pilocarpine-induced seizures and discusses them in the larger context of their potential involvement in the changes that precede the development of epilepsy. FINDINGS: Adult rats received pilocarpine to induce SE and 90 min after seizure onset were treated with diazepam to mitigate seizures. Rats were subsequently deeply anesthetized and brain regions (hippocampus, piriform cortex, neocortex, and cerebellum) were freshly dissected at 2, 6, and 24 h or 5 days after seizures. Using methodology identical to our previous studies, simultaneous assay of multiple cytokines (CCL2, CCL3, CCL5, interleukin IL-1ß, tumor necrosis factor (TNF-α)), and vascular endothelial growth factor (VEGF) was performed and compared to control rats. These proteins were selected based on existing evidence implicating them in the epileptogenic progression. A robust increase in CCL2 and CCL3 concentrations in the hippocampus, piriform cortex, and neocortex was observed at all time-points. The concentrations peaked with a ~200-fold increase 24 h after seizures and were two orders of magnitude greater than the significant increases observed for CCL5 and IL-1ß in the same brain structures. TNF-α levels were altered in the piriform cortex and neocortex (24 h) and in the hippocampus (5 days) after SE. CONCLUSIONS: Pilocarpine-induced status epilepticus causes a rapid increase of multiple cytokines in limbic and neocortical regions. Understanding the precise spatial and temporal pattern of cytokines and chemokine changes could provide more viable therapeutic targets to reduce, reverse, or prevent the development of epilepsy following a precipitating injury.
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Quimiocina CCL2/metabolismo , Quimiocina CCL3/metabolismo , Quimiocina CCL5/metabolismo , Hipocampo/metabolismo , Interleucina-1beta/metabolismo , Neocórtex/metabolismo , Córtex Piriforme/metabolismo , Estado Epiléptico/metabolismo , Animais , Biomarcadores/metabolismo , Modelos Animais de Doenças , Masculino , Pilocarpina/efeitos adversos , Ratos , Ratos Sprague-Dawley , Estado Epiléptico/induzido quimicamente , Fatores de Tempo , Fator de Necrose Tumoral alfa/metabolismo , Fator A de Crescimento do Endotélio Vascular/metabolismoRESUMO
Neurogenesis occurs in the adult mammalian brain in discrete regions related to olfactory sensory signaling and integration. The olfactory receptor cell population is in constant turn-over through local progenitor cells. Also, newborn neurons are added to the olfactory bulbs through a major migratory route from the subventricular zone, the rostral migratory stream. The olfactory bulbs project to different brain structures, including: piriform cortex, amygdala, entorhinal cortex, striatum and hippocampus. These structures play important roles in odor identification, feeding behavior, social interactions, reproductive behavior, behavioral reinforcement, emotional responses, learning and memory. In all of these regions neurogenesis has been described in normal and in manipulated mammalian brain. These data are reviewed in the context of a sensory-behavioral hypothesis on adult neurogenesis that olfactory input modulates neurogenesis in many different regions of the brain.
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Aprendizagem/fisiologia , Neurogênese/fisiologia , Odorantes , Condutos Olfatórios/fisiologia , Neurônios Receptores Olfatórios/fisiologia , Tonsila do Cerebelo/fisiologia , Animais , Movimento Celular/fisiologia , Proliferação de Células , Emoções , Comportamento Alimentar , Hipocampo/fisiologia , Bulbo Olfatório/fisiologia , Comportamento SocialRESUMO
Annually, more than a million persons experience traumatic brain injury (TBI) in the US and a substantial proportion of this population develop debilitating neurological disorders, such as, paralysis, cognitive deficits, and epilepsy. Despite the long-standing knowledge of the risks associated with TBI, no effective biomarkers or interventions exist. Recent evidence suggests a role for inflammatory modulators in TBI-induced neurological impairments. Current technological advances allow for the simultaneous analysis of the precise spatial and temporal expression patterns of numerous proteins in single samples which ultimately can lead to the development of novel treatments. Thus, the present study examined 23 different cytokines, including chemokines, in the ipsi and contralateral cerebral cortex of rats at 24 h after a fluid percussion injury (FPI). Furthermore, the estimation of cytokines were performed in a newly developed multiplex assay instrument, MAGPIX (Luminex Corp), and compared with an established instrument, Bio-Plex (Bio-Rad), in order to validate the newly developed instrument. The results show numerous inflammatory changes in the ipsi and contralateral side after FPI that were consistently reported by both technologies.
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The black reaction allowed Golgi to describe with amazing detail the morphology of glial cells as well as their proximal location and intimate connections with neurons and blood vessels. Based on this location, Golgi hypothesized that glial cells were functional units in the nervous system and were not merely a structural support medium. Relatively recent advances have confirmed the importance of glial cells in nervous system function and disease. The occurrence of gliosis is considered the hallmark of damaged tissue. Gliosis can differentially influence disease development and it is a prevailing characteristic of temporal lobe epilepsy. Its presence in the epileptic hippocampi might contribute to hyperexcitability, the development of aberrant neurogenic changes and inflammatory processes related to seizures. Considering the accumulating data regarding the pathological role of glial cells in epilepsy, novel therapeutic approaches that target glial cells are being explored. Such therapeutic approaches directed to glial cells present a novel perspective for the management of refractory pathologies.
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Neuroanatomia/história , Neurogênese , Neuroglia/citologia , Epilepsia/história , Epilepsia/patologia , História do Século XIX , História do Século XX , Humanos , Inflamação/patologia , Neurogênese/fisiologia , Neuroglia/fisiologiaRESUMO
It is known that the incidence of epilepsy increases with age, but only a few studies have investigated the consequences and mechanisms of seizure and epilepsy in aged animals. Astrocytic changes are known to directly influence neuronal excitability and seizure susceptibility. However, information regarding alterations to astrocytes after seizures in aged animals is lacking in the literature. In the present study, the density and morphology of astrocytes expressing GFAP were investigated in the hippocampus of aged rats that experienced status epilepticus induced by pilocarpine. One month after seizures, astrocytes in aged rats have increased volume and present activated morphology. Despite these morphological changes, the density of astrocytes was not altered in the hippocampus of aged rats after seizures.
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BACKGROUND: Neuroinflammation occurs after seizures and is implicated in epileptogenesis. CCR2 is a chemokine receptor for CCL2 and their interaction mediates monocyte infiltration in the neuroinflammatory cascade triggered in different brain pathologies. In this work CCR2 and CCL2 expression were examined following status epilepticus (SE) induced by pilocarpine injection. METHODS: SE was induced by pilocarpine injection. Control rats were injected with saline instead of pilocarpine. Five days after SE, CCR2 staining in neurons and glial cells was examined using imunohistochemical analyses. The number of CCR2 positive cells was determined using stereology probes in the hippocampus. CCL2 expression in the hippocampus was examined by molecular assay. RESULTS: Increased CCR2 was observed in the hippocampus after SE. Seizures also resulted in alterations to the cell types expressing CCR2. Increased numbers of neurons that expressed CCR2 was observed following SE. Microglial cells were more closely apposed to the CCR2-labeled cells in SE rats. In addition, rats that experienced SE exhibited CCR2-labeling in populations of hypertrophied astrocytes, especially in CA1 and dentate gyrus. These CCR2+ astroctytes were not observed in control rats. Examination of CCL2 expression showed that it was elevated in the hippocampus following SE. CONCLUSION: The data show that CCR2 and CCL2 are up-regulated in the hippocampus after pilocarpine-induced SE. Seizures also result in changes to CCR2 receptor expression in neurons and astrocytes. These changes might be involved in detrimental neuroplasticity and neuroinflammatory changes that occur following seizures.
Assuntos
Quimiocina CCL2/metabolismo , Hipocampo/metabolismo , Neuroglia/metabolismo , Neurônios/metabolismo , Receptores CCR2/metabolismo , Estado Epiléptico/metabolismo , Animais , Astrócitos/metabolismo , Região CA1 Hipocampal/irrigação sanguínea , Região CA1 Hipocampal/metabolismo , Contagem de Células , Giro Denteado/irrigação sanguínea , Giro Denteado/metabolismo , Células Endoteliais/metabolismo , Hipocampo/irrigação sanguínea , Imuno-Histoquímica , Microglia/metabolismo , Microscopia Confocal , Pilocarpina , Ratos , Ratos Sprague-Dawley , Convulsões/metabolismo , Estado Epiléptico/induzido quimicamenteRESUMO
Microglia are found throughout the central nervous system, respond rapidly to pathology and are involved in several components of the neuroinflammatory response. Iba1 is a marker for microglial cells and previous immunocytochemical studies have utilized this and other microglial-specific antibodies to demonstrate the morphological features of microglial cells at the light microscopic level. However, there is a paucity of studies that have used microglial-specific antibodies to describe the ultrastructural features of microglial cells and their processes. The goal of the present study is to use Iba1 immuno-electron microscopy to elucidate the fine structural features of microglial cells and their processes in the hilar region of the dentate gyrus of adult Sprague-Dawley rats. Iba1-labeled cell bodies were observed adjacent to neurons and capillaries, as well as dispersed in the neuropil. The nuclei of these cells had dense heterochromatin next to the nuclear envelope and lighter chromatin in their center. Iba1-immunolabeling was found within the thin shell of perikaryal cytoplasm that contained the usual organelles, including mitochondria, cisternae of endoplasmic reticulum and Golgi complexes. Iba1-labeled cell bodies also commonly displayed an inclusion body. Iba1-labeled cell bodies gave rise to processes that often had a small side branch arise within 5 mum of the microglial cell body. These data showing "resting" Iba-1 labeled microglial cells in the normal adult rat dentate gyrus provide a basis for comparison with the morphology of microglial cells in disease and injury models where they are activated or phagocytotic.