Rol de la neuroglia en el trastorno del espectro autista / Role of neuroglia in autism spectrum disorder

RESUMEN: El trastorno del espectro autista (TEA) se caracteriza por presentar déficits persistentes en la comunicación y en la interacción social. Además, patrones de comportamiento, intereses o actividades de tipo restrictivo o repetitivo. Su etiología es compleja y heterogenia, y los mecanismos neurobiológicos que dan lugar al fenotipo clínico aún no se conocen por completo. Las investigaciones apuntan a factores genéticos y ambientales que afectan el cerebro en desarrollo. Estos avances coinciden con un aumento en la comprensión de las funciones fisiológicas y el potencial patológico de la neuroglia en el sistema nervioso central (SNC) que llevó a la noción de la contribución fundamental de estas células en el TEA. Así, el objetivo de este artículo fue revisar brevemente los factores de riesgo clave asociados al TEA y luego, explorar la contribución de la neuroglia en este trastorno. Se destaca el rol de los astrocitos, los microglocitos y los oligodendrocitos en el control homeostático del SNC, en la regulación inmunitaria del cerebro y en la mielinización axonal, así como el mal funcionamiento y las alteraciones morfológicas de estas células en los cerebros autistas.

SUMMARY: Autism spectrum disorder (ASD) is characterized by persistent deficits in communication and social interaction, as well as restrictive or repetitive activities or interests. Its etiology is complex and heterogeneous, and the neurobiological mechanisms that give rise to the clinical phenotype are not yet fully understood. Research points to genetic and environmental factors that affect the developing brain. These advances are consistent with an enhanced understanding of the physiological functions and pathological potential of neuroglia in the central nervous system (CNS) which supports the conclusion of the contribution of these cells in ASD. Therefore, the objective of this article was to briefly review the key risk factors associated with ASD and then explore the contribution of glia in this disorder. The role of astrocytes, microgliocytes and oligodendrocytes in the homeostatic control of the CNS in the immune regulation of the brain and in axonal myelination, as well as malfunction and morphological alterations of these cells in autistic brains are emphasized.

Immunohistochemical analysis of retinoblastoma cell phenotype using neuronal and glial cell markers / Análise imuno-histoquímica do fenótipo de células de retinoblastoma utilizando marcadores de células neuronais e gliais

ABSTRACT Purpose: The cellular origin of retinoblastoma is uncertain as constituent tumor cells heterogeneously express markers of both immature and mature retinal cells. An immunohistochemical analysis of cellular origin may yield valuable insights into disease progression and treatment options. This study aimed to determine the cellular origin of retinoblastoma in a large case series and correlate these findings with histopathological prognostic factors. Methods: Thirty-nine retinoblastoma cases were histopathologically diagnosed and analyzed by immunohistochemistry using monoclonal antibodies against the immature neural cell marker SRY-box containing gene 2 (SOX-2), the mature neuronal cell marker microtubule-associated protein 2 (MAP2), and the mature glial cell marker glial fibrillary acidic protein (GFAP). Histopathological features were also evaluated, including patterns of growth, differentiation, vitreous seeding, and choroidal/scleral, optic nerve, and anterior chamber invasion. Two retinoblastoma cell lines, WERI-1 and Y79, were studied by immunocytochemistry using the same antibodies. Results: Expression of SOX-2 was strong in 97.4% of retinoblastoma cases, while MAP-2 was expressed in 59% of cases. Immunostaining for GFAP was positive only in reactive stromal astrocytes interspersed amongst tumor cells and in peritumoral tissue. There was no correlation between histopathological prognostic factors and immunohistochemical markers. Retinoblastoma cell lines showed strong positivity for SOX2 (90% of WERI-1 cells and 70% of Y79 cells) and MAP2 (90% of cells in both lines). GFAP was completely negative in both cell lines. Conclusion: The majority of retinoblastomas and both RB cell lines expressed an immature neural and/or a mature neuronal cell marker, but not a glial marker. These results indicate a typical neuroblast or neuronal origin and eliminate astrocyte differentiation from neural stem cells as the source of retinoblastoma.

RESUMO Objetivos: Este estudo visa determinar a origem do retinoblastoma em um número de casos e correlacionar essos achados com fatores prognósticos e histopatológicos conhecidos. Métodos: Trinta e nove casos de retinoblastoma foram diagnosticados e analisados com imuno-histoquímica usando marcadores de anticorpos monoclonais contra as células de retina imaturas (SOX-2: SRY-box containing gene 2), contra as células da retina maturas (MAP2: microtubule -associated protein 2) e contra as células gliais maturas (GFAP: glial fibrillar acidic protein). Foram avaliadas características microscópicas dos casos (grau de diferenciação, presença de semeadura vítrea, invasão de coroide/esclera, nervo óptico e câmara anterior). Duas linhas celulares de retinoblastoma (WERI-1 e Y79) também foram testadas, utilizando os três marcadores. Resultados: A expressão de SOX-2 foi positiva em 97,4% dos casos de retinoblastoma, enquanto MAP2 foi positivo em 59% dos casos. GFAP foi apenas positivo no estroma (astrócitos reativos). Não houve correlação entre preditores histopatológicos e marcadores imunohistoquímicos avaliados. As linhagens celulares mostraram positividade para SOX-2 (90% em WERI-1 e 70% das células Y79). Ambas as linhagens celulares se mostraram fortemente positivas con MAP2 (90%), enquanto não houve expressão de GFAP em nenhuma das linhas celulares estudadas. Conclusões: A maioria das células de retinoblastoma desta série de casos expressa marcadores de células retinianas imaturas, além de marcadores de células maduras. As linhas celulares Y79 e WERI-1 apresentaram imunomarcação para ambos os marcadores neurais em percentagens semelhantes a dos casos avaliados. Portanto, estes resultados confirmam a origem neural do tumor em particular. Alem disso, a ausência de células positivas para GFAP no tumor descarta diferenciação de astrócitos em retinoblastoma.

Spinal cord injury-induced astrocyte migration and glial scar formation: Effects of magnetic stimulation frequency.

The effects of magnetic stimulation on spinal cord injury-induced migration of white matter astrocytes were studied using an established animal model. Ethidium bromide was injected into the dorsal spinal cord funiculus of adult Sprague-Dawley rats on the left side at T10-11. Animals then received 1.52 Tesla-pulsed magnetic stimulation for 5 min at different frequencies (0-20 Hz) for 14 consecutive days. Selected animals received the non-competitive MEK1/2 inhibitor U0126 (10 μM), prior to stimulation at 10 Hz. Lesion volumes were measured in hematoxylin/eosin-stained sections. Expression of glial fibrillary acidic protein (GFAP), microtubule associated protein-2 (MAP-2) and extra-cellular signal-regulated kinase1/2 (ERK1/2) near the epicenter of injury was examined by Western blotting with quantification using an image analysis system. Lesion volumes decreased and GFAP and p-ERK1/2 expression increased with increasing magnetic stimulation frequency (0-10 Hz). MAP-2 expression was not affected at any frequency. Pretreatment with U0126 reduced GFAP and ERK1/2 expression and increased lesion volumes in response to stimulation at 10 Hz. It is concluded that magnetic stimulation increases the migration of astrocytes to spinal cord lesions. Activation of the ERK1/2 signaling pathway is proposed to mediate astrocyte migration and glial scar formation in response to spinal cord injury.

The review of the methods to obtain non-neuronal cells to study glial influence on Amyotrophic Lateral Sclerosis pathophysiology at molecular level in vitro / Revisão dos métodos de obtenção de células não neuronais para o estudo da fisiopatologia da Esclerose Lateral Amiotrófica ao nível molecular in vitro

PURPOSE: Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease that displays a rapid evolution. Current treatments have failed to revert clinical symptoms because the mechanisms involved in the death of motoneuron are still unknown. Recent publications have put non-neuronal cells, particularly, astrocyte and microglia, in the scenario of pathophisiology of the disease. Animal models for ALS, particularly transgenic mice expressing the human SOD1 gene with a G93A mutation (hSOD1), are available and display the phenotype of the disease at cellular and clinical levels. However, it is a lack of detailed information regarding the methods to study the disease in vitro to better understand the contribution of non-neuronal cells in the onset and progression of the pathology. METHODS: Colonies of Swiss mice and transgenic mice expressing hSOD1 mutation as well as non-transgenic controls (wild-type) were amplified after a genotyping evaluation. Disease progression was followed behaviorally and mortality was registered. Highly purified primary cultures of astrocytes and microglia from mouse spinal cord were obtained. Cells were identified by means of GFAP and CD11B immunocytochemistry. The purity of astroglial and microglial cell cultures was also accompanied by means of Western blot and RT-PCR analyses employing a number of markers. RESULTS: The disease onset was about 105 days and the majority of transgenic mice displayed the disease symptoms by 125 days of age and reached the endpoint 20 days later. A substantial motor weakens was registered in the transgenic mice compared to wild-type at the end point. Immunocytochemical, biochemical and RT-PCR analyses demonstrated a highly purified primary cultures of spinal cord astrocytes and microglia. CONCLUSION: It is possible to achieve highly purified primary cultures of spinal cord astrocytes and microglia to be employed in cellular and molecular analyses of the influence of such non-neuronal cells in the pathophysiology of ALS.

OBJETIVO: A esclerose lateral amiotrófica (ELA) é uma doença neurodegenerativa fatal com evolução rápida. Os tratamentos atualmente disponíveis falham em reverter os sintomas porque os mecanismos envolvidos na morte do neurônio motor ainda não são conhecidos. Publicações recentes colocam as células não neuronais, particularmente o astrócito e a microglia, no cenário da fisiopatologia da doença. Modelos animais para a ELA, particularmente os camundongos transgênicos que expressam o gene da SOD1 humana (hSOD1) mutante estão disponíveis e mostram o fenótipo da doença ao nível celular e clínico. Entretanto, informações detalhadas são escassas sobre os métodos de estudo da doença in vitro para a melhor compreensão da participação das células não neuronais no início e na progressão da patologia. MÉTODOS: Colônias de camundongos Swiss e camundongos transgênicos que expressam a hSOD1 mutante assim como os controles não transgênicos (selvagem) foram amplificadas após avaliação genotípica. A progressão da doença foi acompanhada pelo comportamento e a mortalidade foi registrada. Culturas primárias altamente purificadas de astrócitos e microglia da medula espinal dos camundongos foram obtidas. As células foram identificadas pela immunocitoquímica da GFAP e CD11B. A pureza das culturas de astrócitos e microglia foi acompanhada pelas análises do Western blot e RT-PCR empregando-se marcadores específicos. RESULTADOS: Os primeiros sinais da doença ocorreram por volta dos 105 dias de vida e a maioria dos camundongos transgênicos já estava com a doença manifestada aos 125 dias de idade e alcançaram o estágio terminal aproximadamente 20 dias depois. Fraqueza substancial da força muscular foi registrada nos animais transgênicos comparados com os animais selvagens. Análises imuncitoquímica, bioquímica e pelo RT-PCR demonstraram culturas primárias altamente purificadas de astrócito e microglia da medula espinal dos camundongos. CONCLUSÃO: É possível obter culturas purificadas de astrócitos e microglia da medula espinal do camundongo a ser empregadas em análises celulares e moleculares da influência destas células não neuronais na fisiopatologia da ELA.

Neurobiología de la glía y sus funciones en el desarrrollo, la fisiología y la patología del SNC / The neurobiology of glial cells and the function they perform in the development, physiology and the pathology of the Central Nervous System (CNS)

Las células gliales presentan una función similar a sus homólogos más excitables del sistema nervioso central (SNC), las neuronas. Dentro del sistema nervioso en desarrollo, los astrocitos y células de Schwann ayudan activamente a promover la formación de sinapsis y la función, e incluso han sido implicados en la eliminación de sinapsis. En el cerebro adulto, los astrocitos responden a la actividad sináptica por la liberación de los transmisores que modulan esta actividad. De esta forma, las células gliales son participantes activos en la función cerebral. Investigaciones recientes han cambiado la percepción de la glía, que además de ser células de apoyo y soporte para las neuronas, son socios dinámicos que participan en el metabolismo del cerebro y la comunicación entre las neuronas. El descubrimiento de nuevas funciones gliales coincide con los estudiois crecientes de la participación de la glía en las enfermedades cerebrales más comunes, como el traumatismo craneoencefálico, el accidente cerebrovascular, la lesión de la médula espinal, la esclerosis múltimple, la epilepsia, la enfermedad de Alzheimer, la enfermedad de Parkinson, la esclerosis lateral amiótica, el síndrome de Down, el glioma, el trastorno depresivo mayor y el autismo. Sin embargo, quedan muchas preguntas sobre la identidad de la glía y su importancia.

Glial cells have a function similar to their counterparts more excitable central nervous system (CNS), neurons. Within the developing nervous system, astrocytes and Schwann cells actively help to promote synapse formation and function, and have even been involved in the elimination of synapses. In the adulto brain, the astrocytes respond to synaptic activity by realeasing transmitters that modulate synaptic activity. Thus, glia are active participants in brain function. Recent reserch has changed the perception of glia, in addition to help and support cells to neurons, are also dynamic partners participating in brain metabolism and communication between neurons. The discovery fo new glial functions coincides with growing studies of the involvement of glia in brain diseases are the most common head injury, stroke, injury to the spinal cord, multiple sclerosis, epilepsy. Alzheimer's disease, Parkinson's disease, amyotrophic lateral sclerosis, Down's syndrome, glioma, mayor depressive disorder and autism. Many questions remain about the identity of the glial and importance.

Effects of retinoic acid on ischemic brain injury-induced eurogenesis

Neurogenesis can be induced by pathological conditions such as cerebral ischemia. However the molecular mechanisms or modulating reagents of the reactive neurogenesis after the cerebral ischemia are poorly characterized. Retinoic acid (RA) has been shown to increase neurogenesis by enhancing the proliferation and neuronal differentiation of forebrain neuroblasts. Here, we examined whether RA can modulate the reactive neurogenesis after the cerebral ischemia. In contrast to our expectation, RA treatment decreased the reactive neurogenesis in subventricular zone (SVZ), subgranular zone (SGZ) and penumbral region. Furthermore, RA treatment also decreased the angiogenesis and gliosis in penumbral region.

Nasal glial heterotopy in childhood: a case report highlighting the morphological and immunohistochemical features.

We present a case of a 5 months old infant who presented with difficulty in breathing and a visible intranasal swelling. Clinical examination revealed a reddish mass medial to the middle turbinate in the left nasal cavity. MRI was done and a provisional diagnosis of nasal glioma was suggested. The mass was surgically excised and sent for histopathology which showed it to be comprising of astrocytes and neuroglial fibers intermixed with a fibrovascular connective tissue stroma. The presence of Glial fibrillary acid protein (GFAP) confirmed the presence of glial tissue.

Imunoistoquímica em oligodendrogliomas / Immunohistochemstry in oligodendrogliomas

Os oligodendrogliomas (OL) são tumores gliais caracterizados histologicamente pela presença de núcleo redondo e homogêneo com halo claro perinuclear. A diferenciação microscópica desses tumores com neurocitoma central, DNT e algumas vezes com ependimoma de células claras pode ser difícil. O estudo imunoistoquímico com marcadores glial e neuronal tem sido utilizado e pode auxiliar no diagnóstico diferencial. O objetivo do presente estudo foi determinar a diferenciação neuronal e glial por meio de técnica imunoistoquímica utilizando anticorpos de rotina em tumores com características microscópicas de OL. Foram estudados 42 pacientes com idade entre 4 e 60 anos. Dez apresentavam sinais de maior malignidade (anaplásico). Trinta e três casos (78,5%) mostraram positividade para GFAP, sendo em 10 focal e 6 casos com expressão intensa. Doze casos (28,5%) apresentaram positividade para NSE e/ou sinaptofisina, demonstrando alguma diferenciação neuronal, principalmente focal. Trinta e quatro casos (80,9%) foram positivos para S-100 e três casos (7,1%) foram positivos focalmente para NeuN. Concluimos que áreas focais de diferenciação neuronal e/ou glial podem estar presente em OL típicos e, portanto, é necessário cautela no diagnóstico diferencial em amostras pequenas de tumor. A positividade difusa para marcadores neuronais deve sugerir o diagnóstico de neurocitoma central.

Astrocitoma pilocítico: ¿su comportamiento es siempre benigno?: a propósito de un caso / Pilocytic astrocytoma: its behavior is always benign?:a purpose of a case

Lactante mayor femenina de 15 meses de edad, con clínica de dificultad para la marcha, paresia de hemicuerpo derecho, desviación de la comisura labial hacia lado izquierdo, ptosis palpebral parcial ipsilateral. En la Resonancia Magnética Computarizada de cráneo con contraste reporta lesión ocupante de espacio intraxial temporo-parietal de aspecto quistico, con masa mural compatible con ASTROCITOMA PILOCITICO, corroborado con estudios histopatológico. En el presente trabajo se destaca que los astrocitomas pilocíticos aparecen con mayor frecuencia en la infancia y cuya ubicación predilectoria se encuentra a nivel del Cerebelo, sin embargo nuestro caso clínico presenta una ubicación a nivel supratentorial, siendo esta mas frecuente en los adultos que en los infantes, por lo que no se correlaciona con las estadísticas establecidas a nivel mundial y de diversos estudios realizados para los tumores primarios benignos, específicamente, el astrocitoma pilocítico, por tal motivo quisimos traer a colación el presente estudio.

Gliosarcoma: report of four cases with immunohistochemical findings

Gliossarcoma (GSa) é uma neoplasia primária rara do sistema nervoso central, caracterizada por padrão histológico bifásico incluindo componentes tanto glial como sarcomatoso. São discutidos os aspectos clínicos, morfológicos e imunohistoquímicos de quatro casos de GSa e seus mecanismos patogêneticos. A relação masculino/feminino foi 3:1. A média de idade foi 39 anos, variando de 19 a 48. Cefaléia foi a manifestação predominante. Todos os pacientes foram submetidos a craniotomia com microcirurgia e ressecção total do tumor. O diagnostico foi suspeitado devido à arquitetura microscópica e foi confirmada por presença de fibras de reticulina através de técnicas de histoquímica. A análise imuno-histoquímica foi positiva para p53 tanto em células gliais como em células sarcomatosas nos quatro casos. EGFR foi localmente positivo em células gliais em apenas um caso. Esses achados apoiam uma origem monoclonal do GSa relacionada com alteração no Tp53, gene supressor de tumor. No entanto, outras vias alternativas na gênese desses tumores não podem ser afastadas.

Gangliogliomas: A report of five cases.

Gangliogliomas are rare tumors of the Central Nervous System. Five gangliogliomas were diagnosed out of 1560 brain tumours surgically resected out in a period of 5 years accounting for 0. 32%. We have tried to discuss in detail the pathological features of these tumours and have mentioned the clinical and radiological features associated with them. All the slides, tissue blocks and pathology reports of the surgical specimens of gangliglioma were reviewed and the clinical and radiological data reviewed. The ages of the patients ranged from 7-65 years with 4 males and 1 female. The tumors were located in the lateral ventricle (a rare site), temporal, parietal and the frontal lobes with duration of seizures varying from 1-9 years. The tumors were diagnosed by the presence of a dual population of neoplastic ganglionic and glial components. The glial components consisted of pilocytic astrocytes (l case), fibrillary astrocytes (2 cases), oligodendrocytes (1 case) and anaplastic astrocytes and oligodendrocytes (1 case). There was one-grade I GG, three-Grade II GGs and one-grade III GG. Astrocytes were the commonest glial component of GGs, either pilocytic or fibrillary. Oligodendrocytes as the glial component of GGs was seen in 2 cases one of which was anaplastic and this is a rare finding.

Glial Choristoma in the Middle Ear and Mastoid Bone: A Case Report

Heterotopic brain tissue usually involves extracranial midline structures of the head and neck such as nose, nasopharynx, and oral cavity. Its occurrence in the non-midline structures, including middle ear, is rare. We described a 50-yr-old-man with heterotopic glial tissue in the middle ear and mastoid bone. The patient presented with progressive hearing loss for 8 yr. There was no history of congenital anomalies, trauma, or ear surgery. Computed tomography revealed a mass-like lesion with soft tissue density occupying the middle ear cavity and mastoid antrum. At the operation, a graywhite fibrotic mass was detected in the epitympanic area. Mesotympanum and ossicles were intact. The patient underwent left simple mastoidectomy with type I tympanoplasty. During operation, definite cranial bone defect or cerebrospinal fluid leakage was not found. Histologically, the lesion was composed of exclusively mature, disorganized glial tissue with fibrovascular elements in a rather loose fibrillary background. Glial tissue showed diffuse positive reaction for glial fibrillar acidic protein and S100 protein on immunohistochemical study.

Extranasal glial heterotopia: case report.

Glial heterotopia or the occurrence of isolated non-teratomatous extracranial glial tissue is rare. We report a neonate with extensive extranasal glial heterotopia involving the left buccopharyngeal region, palate and base of the skull and presenting with respiratory distress and a bleeding oral mass. A staged operative approach was adopted to excise the lesion. The literature on the subject is briefly reviewed.

Activation of Embryonic Intermediate Filaments Contributes to Glial Scar Formation after Spinal Cord Injury in Rats

The expression of two intermediate filaments, nestin and vimentin, was studied in spinal cord injury (SCI) to elucidate their roles in the formation of glial scars. Rats were sacrificed 1, 4, and 7 days after induction of compression injury of the spinal cord using an aneurysm clip. The affected spinal cords were studied using antibodies against nestin and vimentin intermediate filaments. One day after spinal cord injury, some clusters of nestin-positive vessels were detected in the center of the injury, but few were seen in other cell types. Vimentin immunostaining was detected in some glial cells in the center and its level of immunoreactivity was enhanced in the ependymal cells of the central canal. On days 4 and 7 after spinal cord injury, astrocytes and some ependymal cells in the central canal were stained positively for nestin and increased expression of nestin was observed in vessels. Vimentin was detected in some macrophages and astrocytes in the lesions. Nestin was co-localized with glial fibrillary acidic protein in some glial cells in SCI. These findings imply that spinal cord cells in adult animals have embryonic capacity, and these cells are activated after injury, which in turn contributes to repair of spinal cord injury through formation of a glial scar.

Retinoblastoma--a histologic and immunohistologic study.

Histopathology and various immunohistochemical markers were studied in 40 cases of human retinoblastoma. In histopathology, tumour type, extent and invasion were studied. In immunohistochemistry, both glial and neural markers were used to know the histogenesis of this tumour. The glial markers, glial fibrillary acidic protein and vimentin, were detected in retinal astrocytes and Muller's cells in normal retina and perivascular glia in retinoblastoma. The neural marker, neurone-specific enolase stained neurones in outer and inner nuclear layers in normal retina, Flexner-Wintersteiner rosettes in retinoblastoma and tumour cells is differentiated retinoblastoma. Another neural marker, neurofilament triplet polypeptide stained neurones in inner nuclear layer of normal retina and Flexner-Wintersteiner rosettes in well-differentiated retinoblastoma. These results support the view that retinoblastoma has predominantly neuronal origin.