Metabolism and brain cancer

Cellular energy metabolism is one of the main processes affected during the transition from normal to cancer cells, and it is a crucial determinant of cell proliferation or cell death. As a support for rapid proliferation, cancer cells choose to use glycolysis even in the presence of oxygen (Warburg effect) to fuel macromolecules for the synthesis of nucleotides, fatty acids, and amino acids for the accelerated mitosis, rather than fuel the tricarboxylic acid cycle and oxidative phosphorylation. Mitochondria biogenesis is also reprogrammed in cancer cells, and the destiny of those cells is determined by the balance between energy and macromolecule supplies, and the efficiency of buffering of the cumulative radical oxygen species. In glioblastoma, the most frequent and malignant adult brain tumor, a metabolic shift toward aerobic glycolysis is observed, with regulation by well known genes as integrants of oncogenic pathways such as phosphoinositide 3-kinase/protein kinase, MYC, and hypoxia regulated gene as hypoxia induced factor 1. The expression profile of a set of genes coding for glycolysis and the tricarboxylic acid cycle in glioblastoma cases confirms this metabolic switch. An understanding of how the main metabolic pathways are modified by cancer cells and the interactions between oncogenes and tumor suppressor genes with these pathways may enlighten new strategies in cancer therapy. In the present review, the main metabolic pathways are compared in normal and cancer cells, and key regulations by the main oncogenes and tumor suppressor genes are discussed. Potential therapeutic targets of the cancer energetic metabolism are enumerated, highlighting the astrocytomas, the most common brain cancer.

Homozygotic intronic GAA mutation in three siblings with late-onset Pompe's disease / Mutação homozigótica intrônica no gene GAA em três irmãos com doença de Pompe de início tardio

Pompe's disease (PD) is a metabolic myopathy caused by the accumulation of lysosomal glycogen, secondary to acid α-glucosidase (GAA) enzyme deficiency. Childhood and late-onset forms are described, differing by the age of onset and symptoms. In this study were analyzed affected siblings with Pompe's disease (PD) and their distinct clinical and pathological presentations. METHOD: Diagnosis was performed by the clinical presentation of limb-girdle dystrophies and respiratory compromise. Confirmatory diagnoses were conducted by muscle biopsy, GAA activity measurement and by GAA gene genotyping. RESULTS: The findings suggested muscular involvement due to GAA deficiency. GAA genotyping showed they are homozygous for the c.-32-3C>A mutation. CONCLUSION: Herein we reported a family where three out of five siblings were diagnosed with late-onset PD, although it is a rare metabolic disease inherited in an autossomal recessive manner. We emphasize the importance of including this presentation within the differential diagnoses of the limb-girdle dystrophies once enzyme replacement therapy is available.

A doença de Pompe (DP) é uma miopatia originada do acúmulo lisossomal de glicogênio, devido à deficiência da enzima α-glicosidase ácida (GAA), sendo descritas formas de inicio precoce e tardio. Neste estudo analisamos retrospectivamente o perfil clinico e patológico de 3 irmãos portadores de doença de Pompe de inicio tardio. MÉTODO: O diagnóstico foi realizado mediante apresentação clinica de distrofia de cinturas associado a comprometimento respiratório, sendo confirmado por biópsia muscular e análise da atividade e genotipagem da GAA. RESULTADOS: Os exames clínicos e laboratoriais demonstram envolvimento muscular devido à deficiência da GAA, com uma mutação c.-32-3C>A em homozigose. CONCLUSÃO: Relatamos os aspectos clínicos e laboratoriais de 3 irmãos afetados por doença de Pompe de início tardio. Enfatizamos a importância de incluir esta patologia no diagnóstico diferencial das distrofias de cinturas, uma vez que para esta patologia específica existe a possibilidade terapêutica através de reposição enzimática.

Bovine myocardial bridge morphology and association with coronary atherosclerosis

Coronary arteries and their branches run through the subepicardial layer and penetrate the myocardium. In some cases, these vessels run intramyocardially for variable lenghts and then return to the subepicardial surface. The cardiac musculature that covers these vessels is known as a myocardial bridge. The presence of a myocardial bridge may protected the covered arterial segment against the development of atherosclerosis. In this report, we examined the pre-, post- and myocardial bridge segments of branches of bovine coronary arteries and compared them to corresponding sections of coronary arteries not covered by a myocardial bridge, in order to establish a possible morphofunctional association. Twelve interventricular paraconal branches from coronary arteries with or without a myocardial bridge (pre-, post- and myocardial bridge segments) were obtained from adult bulls of mixed breed. The samples were processed and stained to detect elastic, collagen and muscle fibers and were analyzed by light microscopy. The histological appearance of the pre-myocardial bridge segments differed from that of the other segments with or without a myocardial bridge in that the intimal layer was well-developed. By analogy, the morphology of the pre-myocardial bridge in bovine vessles suggests that there may be a high incidence of atherosclerosis in the pre-myocardial bridge tissue of human vessels.