Astroglioma conditioned medium increases synaptic elimination and correlates with major histocompatibility complex of class I (MHC I) upregulation in PC12Cells.

Astrocytes are multifunctional glial cells that actively participate in synaptic plasticity in health and disease. Little is known about molecular interactions between neurons and glial cells that result in synaptic stability or elimination. In this sense, the main histocompatibility complex of class I (MHC I) has been shown to play a role in the synaptic plasticity process during development and after lesion of the CNS. MHC I levels in neurons appear to be influenced by astrocyte secreted molecules, which may generate endoplasmic reticulum stress. In vitro studies are of relevance since cell contact can be avoided by the use of astrocyte conditioned medium, allowing investigation of soluble factors isolated from cell direct interaction. Thus, we investigated synaptic preservation by synaptophysin and MHC I immunolabeling in PC12 neuron-like cells exposed to NG97 astroglioma conditioned medium (CM). For that, PC12 cells were cultured and differentiated into neuron-like profile with nerve growth factor. MHC I was induced with interferon beta treatment (IFN), and the effects were compared to PC12 exposure to NG97 CM. Overall, the results show that NG97 CM increases, more than IFN alone, the expression of MHC I, negatively influencing synaptic stability. This indicates that glial soluble factors influence synapse elimination, compatible to in vivo synaptic stripping process, in a cell contact independent fashion. In turn, our results indicate that deleterious effects of astroglioma are not only restricted to rapid growth ratio of the tumor, but also correlated with secretion of stress-related molecules that directly affect neuronal networks.

CDKN2A promoter hypermethylation in astrocytomas is associated with age and sex.

CDKN2A promoter hypermethylation has been widely related to many cancers. In astrocytomas, although CDKN2A (p16(INK4A) protein) is often inactivated, there are still some controversial issues regarding the mechanism by which this alteration occurs. Thus, we analyzed a series of astrocytomas to assess the association between CDKN2A expression and methylation of grade I-IV tumors (WHO) and clinicopathological parameters. DNA extracted from formalin-fixed paraffin-embedded material of 93 astrocytic tumors was available for CDKN2A promoter methylation analysis and p16(INK4A) expression by methylation-specific PCR and immunohistochemistry, respectively. A strong negative correlation between nuclear and cytoplasmic immunostaining and CDKN2A promoter methylation was found. Additionally, a significant negative correlation between CDKN2A promoter methylation and age was observed; also, female patients had statistically more CDKN2A methylated promoters (p = 0.036) than men. In conclusion, CDKN2A inactivation by promoter methylation is a frequent event in astrocytomas and it is related to the age and sex of patients.

Neoplasias astrocitárias e correlação com as proteínas p53 mutada e Ki-67 / Astrocytic neoplasms and correlation with mutate p53 and Ki-67 proteins

As neoplasias astrocitárias correspondem a 60 por cento dos tumores do sistema nervoso central, sendo o estudo da biologia molecular um importante passo para a compreensão da gênese e comportamento biológico destas doenças. As proteínas Ki-67, que é um marcador de proliferação celular, e p53, que é o produto do gene supressor de tumor de mesmo nome, são importantes marcadores tumorais. O objetivo deste estudo foi identificar e quantificar as proteínas Ki-67 e produto do gene supressor de tumor TP53 em diferentes graus de malignidade das neoplasias astrocitárias, bem como analisar suas relações com idade e sexo. Foram estudadas por imuno-histoquímica as proteínas Ki-67 e p53 em 47 pacientes com neoplasias astrocitárias ressecadas cirurgicamente, classificadas previamente e revisadas quanto ao grau de malignidade, de acordo com o proposto pela Organização Mundial da Saúde. Os núcleos celulares imunomarcados foram quantificados no programa Imagelab-softium pela razão paramétrica absoluta entre os núcleos de células positivas e o número total de células tumorais, sendo contadas 1000 células. O delineamento utilizado foi transversal não controlado. Para análise estatística as variáveis foram divididas em grupos, que para a Ki-67 foram ausente, <5 por cento e >5 por cento e para a p53 foram ausente (0), <25 por cento (1+), entre 25 e 50 por cento (2+), entre 50 e 75 por cento (3+) e maior que 75 por cento (4+). Ki-67 esteve presente em 37 casos (78,72 por cento) expressando correlação com maior grau de malignidade (p<0,001) . A p53 esteve presente em 14 casos (35,13 por cento) tendo maior correlação com astrocitoma grau IV (p=0,59). Não houve correlação estatisticamente significativa entre p53 e Ki-67, bem com entre estas variáveis, idade e sexo. Concluiu-se que a hipótese de maior presença de Ki-67 e p53 em neoplasias astrocitárias de maior grau de malignidade, com exceção da correlação entre grau III e p53, é corroborada pelos resultados deste estudo.

[Astrocytic neoplasms and correlation with mutate p53 and Ki-67 proteins]. / Neoplasias astrocitárias e correlação com as proteínas p53 mutada e Ki-67.

The astrocytic neoplasms respond by 60% of the central nervous system tumors, being the study of the molecular biology an important step for the understanding of the genesis and biological behavior of these diseases. The Ki-67 proteins, which are markers of the cellular proliferation, and p53, which is the product of the tumor suppressor gene TP53, are both important tumoral markers. This study intends to identify and quantify the Ki-67 and p53 proteins in astrocytic tumors of different grades of malignancy, as well as to analyze their relations with age and gender. Ki-67 and p53 proteins in 47 patients with surgically resected astrocytic neoplasms were studied through immunohistochemistry. They have been previously classified and reviewed concerning their histological grade, as suggested by the World Health Organization. The immunomarked cellular nuclei were quantified by the program Imagelab-softium for the absolute parametric reason between the nuclei of the positive cells and the total amount of tumoral cells, being counted 1000 cells. The lineation used has been transversal not controlled. For the statistical analysis the variables were divided into groups. For the Ki-67 they were absent, <5% and >5% and for p53 they were absent (0), <25% (1+), between 25 and 50% (2+), between 50 and 75% (3+), and higher than 75% (4+). Ki-67 was present in 37 cases (78.72%) evidencing a correlation with a higher malignancy degree (p<0,001). p53 was present in 14 cases (35.13%) with a higher correlation with astrocytoma grade IV (p=0.59). There has not been a statistically significant correlation between p53 and Ki-67, as well as among these variables, age and gender. The hypotheses of a greater presence of Ki-67 and p53 in astrocytic neoplasms with a higher degree of malignancy, except for the correlation between grade III and p53, is corroborated by the results of this study.

Desmoplastic astrocytoma of infancy: a case report with histopathologic and immunohistochemistry profile.

The clinicopathological features and immunohistochemistry profile of desmoplastic cerebral astrocytoma of infancy are discussed in a 4 month old male infant who presented with an increasing head circumference more pronounced in the last two weeks prior to admission to the University Pediatric Hospital. This is a rare tumor that occurs in infants within the first two years of life and it is characterized by a massive, often cystic, supratentorial lesion usually in the frontoparietal region. It has a biphasic histologic pattern with an astrocytic and desmoplastic component and a good prognosis after total or near total surgical resection. This patient represents the first case of desmoplastic cerebral astrocytoma of infancy diagnosed in the Puerto Rico Medical Center.

Expression of TRH and TRH-like peptides in a human glioblastoma-astrocytoma cell line (U-373-MG).

The human glioblastoma-astrocytoma cell line U-373-MG shows morphological features typical of its neuroectodermal origin. Cells showed positive immunostaining for the glial fibrillary acidic protein. We used this cell culture for studying the putative production of TRH and TRH-related peptides. In a cell extract and conditioned medium, cation and anion exchange chromatography and HPLC revealed the presence of TRH and acidic TRH-like peptides which were identified, at least in part, as pGlu-Glu-ProNH(2). These findings demonstrated that U-373-MG cells are able to produce and release these peptides. Further evidence of TRH synthesis was obtained by amplification using RT-PCR of a 396 bp fragment that corresponds to the TRH precursor mRNA. Our results therefore suggest that the U-373-MG cell line may be a useful model for studying the regulation of TRH and TRH-related peptide production and the interaction of these peptides with other classical neurotransmitter systems. In fact, pilocarpine (a muscarinic cholinergic agonist) enhanced and nicotine (a nicotinic cholinergic agonist) decreased TRH and TRH-related compound production by this cell line. These data also point out that glia may produce substances with neuromodulatory action.

[Classification of the astrocytic gliomas. Brief comments]. / Clasificación de los gliomas astrocíticos. Breves consideraciones.

INTRODUCTION: Gliomas make up approximately 50% of the primary brain tumors of the central nervous system in adults. Astrocytes from between 70 and 75% of these tumors. Historically grading these has been very controversial, in spite of its importance for prognosis and planning treatment. DEVELOPMENT: We have reviewed existing proposals for the classification of astroglial neoplasias, from the initial studies to the latest classification by the World Health Organization. All have pursued the objective of finding the histopathological grade of the neoplasm to relate it to survival and predict prognosis. CONCLUSION: Further knowledge of these tumors is the aim of professionals and others interested in the subject, in the difficult course of finding better and more efficient treatment for these patients.

Pleomorphic xanthoastrocytoma of the retina.

We report two cases of pleomorphic xanthoastrocytomas of the retina. The immunoreactivity to CD68, Fe (Pearls' technique), astrocytes (argentic technique), and antibodies to glial fibrillary acidic protein was tested in tumor cells. Both neoplasms contained cells immunoreactive for glial fibrillary acidic protein and CD68. These tumors, observed in the CNS, first reported by Kepes et al. were found in the retina as well-circumscribed masses with a cystic component. Many large pleomorphic cells contained vesicular and enlarged nuclei with a homogeneous eosinophilic cytoplasm, prominent nucleoli, and calcium deposits. Some cells had a markedly swollen lipidized cytoplasm, whereas others were spindle-shaped and contained multiple nuclei. These findings suggest that our two specimens have an astroglial lineage and are similar to pleomorphic xanthoastrocytomas of the CNS brain and spinal cord. Both reported cases were in female patients who were in their 20s and had glaucoma. After 10 years both are free of disease.