Bevacizumab dose adjustment to improve clinical outcomes of glioblastoma.

BACKGROUND: Glioblastoma (GBM) is one of the most aggressive and vascularized brain tumors in adults, with a median survival of 20.9 months. In newly diagnosed and recurrent GBM, bevacizumab demonstrated an increase in progression-free survival, but not in overall survival. METHODS: We conducted an in silico analysis of VEGF expression, in a cohort of 1082 glioma patients. Then, to determine whether appropriate bevacizumab dose adjustment could increase the anti-angiogenic response, we used in vitro and in vivo GBM models. Additionally, we analyzed VEGFA expression in tissue, serum, and plasma in a cohort of GBM patients before and during bevacizumab treatment. RESULTS: We identified that 20% of primary GBM did not express VEGFA suggesting that these patients would probably not respond to bevacizumab therapy as we proved in vitro and in vivo. We found that a specific dose of bevacizumab calculated based on VEGFA expression levels increases the response to treatment in cell culture and serum samples from mice bearing GBM tumors. Additionally, in a cohort of GBM patients, we observed a correlation of VEGFA levels in serum, but not in plasma, with bevacizumab treatment performance. CONCLUSIONS: Our data suggest that bevacizumab dose adjustment could improve clinical outcomes in Glioblastoma treatment.

Polyethylene glycol improves current methods for circulating extracellular vesicle-derived DNA isolation.

BACKGROUND: Extracellular vesicles (EVs) are small membrane-bound vesicles which play an important role in cell-to-cell communication. Their molecular cargo analysis is presented as a new source for biomarker detection, and it might provide an alternative to traditional solid biopsies. However, the most effective approach for EV isolation is not yet well established. RESULTS: Here, we study the efficiency of the most common EV isolation methods-ultracentrifugation, Polyethlyene glycol and two commercial kits, Exoquick® and PureExo®. We isolated circulating EVs from the bloodstream of healthy donors, characterized the size and yield of EVs and analyzed their protein profiles and concentration. Moreover, we have used for the first time Digital-PCR to identify and detect specific gDNA sequences, which has several implications for diagnostic and monitoring many types of diseases. CONCLUSIONS: Our findings present Polyethylene glycol precipitation as the most feasible and less cost-consuming EV isolation technique.

Caracterización molecular de células progenitoras del parénquima subcortical cerebral humano adulto / Molecular characterization of progenitor cells from subcortical parenchyma of adult human brain

Objetivo: Caracterizar los patrones de expresión de marcadores de indiferenciación y diferenciación y las alteraciones morfológicas de las células progenitoras procedentes de parénquima cerebral humano adulto a lo largo de los pases en cultivo, evaluando su potencial para ser empleadas como fuente de progenitores de oligodendrocitos. Materiales y Métodos: Las células progenitoras se aislaron a partir de dos muestras obtenidas de pacientes sometidos a exéresis temporal por epilepsia. Para comprobar la evolución de los niveles de expresión de marcadores moleculares de diferenciación e indiferenciación en dichas células, se procedió a la extracción de ARNm en cada pase y a su estudio mediante RT-PCR. Se llevó a cabo un análisis de su capacidad proliferativa mediante inmunocitoquímica y un estudio de la evolución morfológica mediante microscopía. Resultados: Las células mostraron capacidad proliferativa durante los primeros pases en cultivo. Además, detectamos la expresión de marcadores de indiferenciación y diferenciación temprana a oligodendrocitos. Conclusión: Las células progenitoras aisladas de parénquima subcortical de cerebro humano pueden ser susceptibles de diferenciación a oligodendrocitos maduros, aunque en protocolos de diferenciación sólo deberían utilizarse pases tempranos (AU)

Objetive: characterize the behavior of progenitor cells isolated from subcortical parenchyma of human brain in culture. We have analyzed the changes in expression patterns of differentiation/undifferentiation markers as well as cell morphology along the passages and evaluated the potential to be further used as oligodendrocyte progenitors source. Material and Methods: We isolated progenitor cells from two different samples of subcortical parenchyma human brain of patients suffering from epilepsy. Cells were kept in culture until they became quiescent/senescent. Every other passages RNAs were isolated and checked for the expression of differentiation and undifferentiation markers by using RT-PCR. Proliferation was also addressed by RT-PCR and immunocytochemistry. We carried out cell morphology studies on semithin and ultrathin sections of cells. Results: We observed decreasing proliferative capacity of both two cell lines which became quiescent/senescent around passages 8-10. We detected the expression of either undifferentiation or early neural and oligodendrocytes differentiation markers. Conclusions: As for the expression of molecular markers, progenitor cells isolated from subcortical parenchyma of human brain have the potential to differentiate into mature oligodendrocytes (AU)