Los pericitos: nuevos enfoques en la terapia regenerativa, patología cerebrovascular y cáncer / Pericytes: new approaches in regenerative therapy, cerebrovascular pathology and cancer

Las células madre mesenquimales son poblaciones multipotentes de células que tienen amplia capacidad de diferenciación, plasticidad y potencial inmunosupresor, lo que las hace una herramienta de gran importancia en las terapias basadas en células.En función de su potencial, se ha determinado que las células perivasculares poseen características de células madre de gran potencial clínico, no obstante, las propiedades biológicas que llevan a su diferenciación son menos comprendidas. Los últimos avances en la comprensión de la relación entre pericitos y las células madre mesenquimales plantean funciones específicas de tejido, así como, su potencial uso terapéutico en las isquemia, tales como, la cerebro-vascular y un mejor entendimiento de la vascularización patológica tumoral. A pesar de la creciente aceptación que las células perivasculares están relacionada o son células madre mesenquimales, existen escasas pruebas experimentales que muestren la diferenciación de pericitos en diferentes tipos de células (Feng et al., 2010). En esta revisión documentamos los fundamentos biológicos de los pericitos que respaldan su uso en terapia regenerativa.

Mesenchymal stem cells are a multipotent population of cells that have extensive capacity for differentiation, plasticity and immunosuppressive potential, making them an important tool in cell-based therapies. According to their potential, it has been determined that perivascular cells have stem cell characteristics of great clinical potential, however, the biological properties that lead to their differentiation are less understood. Recent advances in understanding the relationship between pericytes and mesenchymal stem cells pose tissue-specific functions, as well as their potential therapeutic use in ischemia, such as cerebro-vascular and a better understanding of the pathological tumor vascularization. Despite the growing acceptance that perivascular cells are related, or that they are mesenchymal stem cells, there is little experimental evidence to show the differentiation of pericytes in different cell types (Feng et al., 2010). In this review we document the biological basis of pericytes that support their use in regenerative therapy.

Recent advances in imaging of brain tumors.

The recent advances in brain tumor imaging offer unique anatomical as well as pathophysiological information that provides new insights on brain tumors, directed at facilitating therapeutic decisions and providing information regarding prognosis. This information is presently utilized in clinical practice for initial diagnosis and noninvasive, preoperative grading of tumors, biopsy planning, surgery, and radiation portal planning, as well as, prognostication. The newer advances described in this review include magnetic resonance (MR) diffusion and diffusion tensor imaging with tractography, perfusion imaging, MR spectroscopy, and functional imaging, using the blood oxygenation level dependent (BOLD) technique. Diffusion tensor MR imaging is the only noninvasive in vivo method for mapping white matter fiber tract trajectories in the human brain. In the current clinical practice, one of the most important indications of diffusion tensor imaging (DTI) is to study the relation of a tumor to the adjacent white matter tracts. Perfusion imaging with computed tomography (CT) and magnetic resonance imaging (MRI) is an exciting new radiological technique for noninvasive evaluation of cerebral hemodynamics, in certain definite clinical settings. Cerebral perfusion imaging describes the passage of blood through the brain's vascular network. Perfusion imaging, especially with MRI has become an integral component of the complete radiological assessment of brain tumors. MR Spectroscopy (MSR) is the only noninvasive technique capable of measuring chemicals within the body. MRS distinguishes various metabolites on the basis of their slightly different chemical shifts or resonance frequencies. Functional MRI refers to the demonstration of brain function with neuroanatomic localization on a real-time basis. In patient care, functional MR imaging is primarily used in the preoperative evaluation of the relationship of a brain tumor with an eloquent cortex. The next decade will witness further sophistication of these techniques, with data available from larger studies. It is expected that imaging will continue to provide new and unique insights in neuro-oncology, which should hopefully contribute to the better management of patients with brain tumors.

Alteraciones moleculares de oncogenes en tumores intracraneales / Molecular alterations of oncogenes in brain tumors

Se analizaron 27 tumores intracraneales utilizando sondas moleculares específicas para detectar a los genes CMYC, NMYC y NRAS. Hemos encontrado un importante porcentaje de alteración para estos oncogenes (amplificación y/o rearreglo). Para el oncogen CMYC detectamos el 55 porciento de alteración, 40 porciento para NMYC y el 40 porciento para genes relacionados a RAS. En este estudio fueron incluidos tumores de diferentes diagnósticos histopatológicos en los cuales se detectaron alteraciones combinadas de los genes C y NMYC; este patrón de alteración en la misma muestra tumoral no había sido reportado anteriormente. Además, hemos detectado una alteración frecuente de los genes RAS en adenomas, presentándose amplificación génica así como una expresión incrementada de los mismos. Estos resultados sugieren un papel importante de los genes CMYC, NMYC y RAS en el desarrollo de tumores intracraneales.