Avaliação bioquímica da isquemia cerebral focal, não associada à reperfusão, por oclusão da artéria cerebral média em ratos

Cerebral ischemia is an important event in clinical and surgical neurological practice since it is one of the diseases that most compromise the human species. In the present study 40 adult rats were submitted to periods of focal ischemia of 30, 60 and 90 min without reperfusion and animals submitted to a sham procedure were used as controls. We analyzed the levels of ATP, malondialdehyde and caspase-3. No significant differences in the biochemical measurements were observed between the right and left brain hemispheres of the same animal in each experimental group. Reduced ATP levels were observed after the three periods of ischemia compared to the sham group. No significant increase in malondialdehyde or caspase-3 levels was observed. Despite significant changes in ATP levels, the results indicated cell viability in the ischemic region as shown by the low rates of lipid peroxidation and apoptosis, findings probably related to the lack of reperfusion.Isquemia cerebral é um acontecimento importante na prática neurológica clínica e cirúrgica, uma vez que é uma das doenças que mais comprometem a espécie humana. No presente estudo 40 ratos adultos foram submetidos a períodos de isquemia focal de 30, 60 e 90 min e como controle foram utilizados animais do grupo sham. Foram analisados os níveis de ATP, malondialdeído e caspase-3. Nenhuma diferença significativa nas dosagens bioquímicas foram observadas entre os hemisférios cerebrais direito e esquerdo do mesmo animal em cada grupo experimental. Foi observada redução nos níveis de ATP após os três períodos de isquemia, em comparação com o grupo sham. Nenhum aumento significativo dos níveis de malondialdeído ou caspase-3 foi observado. Apesar das alterações significativas nos níveis ATP, os resultados indicaram viabilidade celular na região isquêmica como demonstrado pela baixa taxa de peroxidação lipídica e apoptose, achados que provavelmente estão relacionados com a falta de reperfusão

Selection of suitable housekeeping genes for expression analysis in glioblastoma using quantitative RT-PCR

Background: Considering the broad variation in the expression of housekeeping genes among tissues and experimental situations, studies using quantitative RT-PCR require strict definition of adequate endogenous controls. for glioblastoma, the most common type of tumor in the central nervous system, there was no previous report regarding this issue.Results: Here we show that amongst seven frequently used housekeeping genes TBP and HPRT1 are adequate references for glioblastoma gene expression analysis. Evaluation of the expression levels of 12 target genes utilizing different endogenous controls revealed that the normalization method applied might introduce errors in the estimation of relative quantities. Genes presenting expression levels which do not significantly differ between tumor and normal tissues can be considered either increased or decreased if unsuitable reference genes are applied. Most importantly, genes showing significant differences in expression levels between tumor and normal tissues can be missed. We also demonstrated that the Holliday Junction Recognizing Protein, a novel DNA repair protein over expressed in lung cancer, is extremely over-expressed in glioblastoma, with a median change of about 134 fold.Conclusion: Altogether, our data show the relevance of previous validation of candidate control genes for each experimental model and indicate TBP plus HPRT1 as suitable references for studies on glioblastoma gene expression.Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)FAEPA-FMRUniv São Paulo, Fac Med, Dept Surg & Anat, BR-14049090 Ribeirao Preto, SP, BrazilUniv São Paulo, Fac Med, Dept Cellular & Mol Biol, BR-14049090 Ribeirao Preto, SP, BrazilUniv São Paulo, Fac Med, Dept Pathol, BR-14049090 Ribeirao Preto, SP, BrazilUniversidade Federal de São Paulo, Dept Neurol & Neurosurg, BR-04023900 São Paulo, BrazilUniv São Paulo, Sch Med, Dept Neurol, BR-01246903 São Paulo, BrazilUniv São Paulo, Fac Med, Dept Pediat, BR-14049090 Ribeirao Preto, SP, BrazilUniversidade Federal de São Paulo, Dept Neurol & Neurosurg, BR-04023900 São Paulo, BrazilFAPESP: 04/12133-6FAPESP: 06/57602-9CNPq: 485342/2006Web of Scienc

Intracranial hypertension

A relação entre o conteúdo da caixa intracraniana e o seu volume determina a pressão intracraniana (PIC), que tem como referência a pressão atmosférica. Em condições normais, a pressão intracraniana tem flutuações determinadas pelos ciclos respiratório e cardíaco. Várias doenças determinam o aumento da pressão intracraniana, sendo a mais freqüente o traumatismo craniencefálico. Para o diagnóstico da hipertensão intracraniana (HIC) deve-se valorizar o quadro clínico, constituído de cefaléia, vômitos e papiledema. Dos exames subsidiários, os mais importantes são os métodos de imagem principalmente Tomografia Computadorizada (TC) e Ressonância Nuclear Magnética (RNM). Para os casos graves de HIC, o ideal durante o tratamento é que a PIC esteja monitorizada. Diversas modalidades podem ser utilizadas, como a hipocapnia induzida pela hiperventilação, os diuréticos osmóticos, a hipotermia e cuidados especiais no tratamento geral dos pacientes.The relation between the volume of the brain and the skull determines the intracranial pressure, that has as reference the atmospheric pressure. In normal conditions the intracranial pressure has oscillations determined by the breathing and heart cycles. Several pathologies determine the increase of the intracranial pressure, the most frequent the head trauma. Should be valued for the diagnosis of the intracranial hypertension (ICH) the clinical picture of headache, vomiting and papilledema. The most important subsidiary exams are the image methods mainly the Computed Tomography (CT) and the Magnetic Resonance Imaging (MRI). Monitorization of the intracranial pressure is important for severe cases of ICH. Several therapeutic modalities can ben used, as hypocarbia induced by hyperventilation, osmotics diuretics, barbiturates, hypothermia and special general measures with the patient

Enhancement of blood-tumor barrier permeability by Sar-[D-Phe8]des-Arg9BK, a metabolically resistant bradykinin B1 agonist, in a rat C6 glioma model

BACKGROUND: While it is well known that bradykinin B2 agonists increase plasma protein extravasation (PPE) in brain tumors, the bradykinin B1 agonists tested thus far are unable to produce this effect. Here we examine the effect of the selective B1 agonist bradykinin (BK) Sar-[D-Phe8]des-Arg9BK (SAR), a compound resistant to enzymatic degradation with prolonged activity on PPE in the blood circulation in the C6 rat glioma model. RESULTS: SAR administration significantly enhanced PPE in C6 rat brain glioma compared to saline or BK (p < 0.01). Pre-administration of the bradykinin B1 antagonist [Leu8]-des-Arg (100 nmol/Kg) blocked the SAR-induced PPE in the tumor area. CONCLUSIONS: Our data suggest that the B1 receptor modulates PPE in the blood tumor barrier of C6 glioma. A possible role for the use of SAR in the chemotherapy of gliomas deserves further study

Neuroproteção hipotérmica pré, intra e pós-isquêmica na isquemia cerebral focal temporária em ratos: análise morfométrica

Objective: To evaluate the neuroprotection of mild hypothermia, applied in different moments, in temporary focal cerebral ischemia in rats. Methods: Rats was divided into Control (C), Sham (S), Ischemic-control(IC), Pre-ischemic Hypothermia (IH1), Intra-ischemic Hypothermia (IH2), and Post-ischemic Hypothermia (IH3) groups. Morphometry was performed using the KS400 software (Carl Zeiss (R)) in coronal sections stained by Luxol Fast Blue. Ischemic areas and volumes were obtained. Results: Statistically, blue areas showed difference for C vs. IC, IC vs. IH1 and IC vs. IH2 (p=0.0001; p=0.01; p=0.03), and no difference between C vs. S, IC vs. IH3 and IH vs. IH2 (p=0.39; p=0.85; p=0.63). Red areas showed difference between C vs. IC, IC vs. IH1 and IC vs. IH2 (p=0.0001; p=0.009; p=0.03), and no difference between C vs. S, IC vs. IH3 and IH1 vs. IH2 (p=0.48; p=0.27; p=0.68). Average ischemic areas and ischemic volumes showed difference between IC vs. IH1 and IC vs. IH2 (p=0.0001 and p=0.0011), and no difference between IC vs. IH3 and IH1 vs. IH2 (p=0.57; p=0.79). Conclusion: Pre-ischemic and intra-ischemic hypothermia were shown to be similarly neuroprotective, but this was not true for post-ischemic hypothermia.Ribeirao Preto Medical School, Universidade de Sao Paulo (FMRP-USP

Expressão de caspase-3 e Bcl-2 em glioblastomas: um estudo imunohistoquímico

The unfavorable prognosis of malignant gliomas can also be explained by the incomplete knowledge of their molecular pathways. Studies regarding the regulatory process of apoptosis in glioblastoma (GBM), the most common malignant glioma, are few, and better knowledge of the expression of pro and anti-apoptotic proteins could collaborate with the development of new treatments founded on molecular basis. The objective of this study was to evaluate by immunohistochemistry the expression of caspase-3 and Bcl-2 in 30 samples of GBMs. The expression of caspase-3 (mean 17.67%) was lower than Bcl-2 (mean 30.92%), a statistically significant result (p<0.0001), suggesting low apoptotic activity in these tumors. Other studies of proteins related to the intrinsic and extrinsic pathway of apoptosis are required to provide additional information of this mechanism in GBMs.O prognóstico desfavorável dos gliomas malignos também pode ser explicado pelo pouco conhecimento dos seus mecanismos moleculares. Estudos relacionados à regulação do processo de apoptose em glioblastoma (GBM), o glioma maligno mais comum, são poucos, e o melhor conhecimento da expressão de proteínas pró e anti-apoptóticas poderia colaborar com o desenvolvimento de novos tratamentos fundamentados sobre a base molecular. O objetivo deste estudo foi avaliar por imunohistoquímica, a expressão de caspase-3 e Bcl-2 em 30 amostras de GBM. A expressão de caspase-3 (média de 17,67%) foi menor que a de Bcl-2 (média de 30,92%), com resultado estatisticamente significante (p<0.0001), sugerindo menor atividade apoptótica nestes tumores. Outros estudos envolvendo proteínas relacionadas à via extrínseca e intrínseca da apoptose são necessários para fornecer informações complementares deste mecanismo em GBMs

Increased Metallothionein I/II Expression in Patients with Temporal Lobe Epilepsy

In the central nervous system, zinc is released along with glutamate during neurotransmission and, in excess, can promote neuronal death. Experimental studies have shown that metallothioneins I/II (MT-I/II), which chelate free zinc, can affect seizures and reduce neuronal death after status epilepticus. Our aim was to evaluate the expression of MT-I/II in the hippocampus of patients with temporal lobe epilepsy (TLE). Hippocampi from patients with pharmacoresistant mesial temporal lobe epilepsy (MTLE) and patients with TLE associated with tumor or dysplasia (TLE-TD) were evaluated for expression of MT-I/II, for the vesicular zinc levels, and for neuronal, astroglial, and microglial populations. Compared to control cases, MTLE group displayed widespread increase in MT-I/II expression, astrogliosis, microgliosis and reduced neuronal population. In TLE-TD, the same changes were observed, except that were mainly confined to fascia dentata. Increased vesicular zinc was observed only in the inner molecular layer of MTLE patients, when compared to control cases. Correlation and linear regression analyses indicated an association between increased MT-I/II and increased astrogliosis in TLE. MT-I/II levels did not correlate with any clinical variables, but MTLE patients with secondary generalized seizures (SGS) had less MT-I/II than MTLE patients without SGS. In conclusion, MT-I/II expression was increased in hippocampi from TLE patients and our data suggest that it is associated with astrogliosis and may be associated with different seizure spread patterns.Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) [2005/56447-7, 2009/53447-7, 2008/52657-5]Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES)Coordenacao de Aperfeicoamento de Pessoal de Nivel Superior (CAPES

A Distinct DNA Methylation Shift in a Subset of Glioma CpG Island Methylator Phenotypes during Tumor Recurrence

Glioma diagnosis is based on histomorphology and grading; however, such classification does not have predictive clinical outcome after glioblastomas have developed. To date, no bona fide biomarkers that significantly translate into a survival benefit to glioblastoma patients have been identified. We previously reported that the IDH mutant G-CIMP-high subtype would be a predecessor to the G-CIMP-low subtype. Here, we performed a comprehensive DNA methylation longitudinal analysis of diffuse gliomas from 77 patients (200 tumors) to enlighten the epigenome-based malignant transformation of initially lower-grade gliomas. Intra-subtype heterogeneity among G-CIMP-high primary tumors allowed us to identify predictive biomarkers for assessing the risk of malignant recurrence at early stages of disease. G-CIMP-low recurrence appeared in 9.5% of all gliomas, and these resembled IDH-wild-type primary glioblastoma. G-CIMP-low recurrence can be characterized by distinct epigenetic changes at candidate functional tissue enhancers with AP-1/SOX binding elements, mesenchymal stem cell-like epigenomic phenotype, and genomic instability. Molecular abnormalities of longitudinal G-CIMP offer possibilities to defy glioblastoma progression