ABSTRACT
BACKGROUND: Given the limitations of current therapies for the reconstruction of bone defects, regenerative medicine has arisen as a new therapeutic strategy along with mesenchymal stem cells (MSCs), which, because of their osteogenic potential and immunomodulatory properties, have emerged as a promising alternative for the treatment of bone injuries. In vivo studies have demonstrated that MSCs have a positive effect on regeneration due to their secretion of cytokines and growth factors that, when collected in conditioned medium (MSC-CM) and applied to an injured tissue, can modulate and promote the formation of new tissue. OBJECTIVE: To evaluate the effectiveness of application of conditioned medium derived from mesenchymal stem cells in bone regeneration in animal and human models. METHODS: We conducted a systematic review with a comprehensive search through February of 2018 using several electronic databases (MEDLINE, EMBASE, SCOPUS, CENTRAL (Ovid), and LILACS), and we also used the "snowballing technique". Articles that met the inclusion criteria were selected through abstract review and subsequent assessment of the full text. We assessed the risk of bias with the SYRCLE and Cochrane tools, and three meta-analyses were performed. RESULTS: We included 21 articles, 19 of which used animal models and 2 of which used human models. In animal models, the application of MSC-CM significantly increased the regeneration of bone defects in comparison with control groups. Human studies reported early mineralization in regenerated bones, and no bone resorption, inflammation, nor local or systemic alterations were observed in any case. The meta-analysis showed an overall favorable effect of the application of MSC-CM. CONCLUSIONS: The application of MSC-CM to bone defects has a positive and favorable effect on the repair and regeneration of bone tissue, particularly in animal models. It is necessary to perform additional studies to support the application of MSC-CM in clinical practice.
ABSTRACT
Se estudió la remoción de colorantes negro reactivo 5 ycristal violeta, mediante la reacción Fenton empleando catalizadoresde Fe2O3 (0-10% m/m de Fe) soportados en carbón activadoobtenido a partir de residuos de rosas. El carbón activado fueobtenido por pirólisis a 500 ºC (1h) seguido de activación con NaOH(1:2 en peso). El soporte fue caracterizado empleando diferentestécnicas químicas y físicas. Los catalizadores de Fe fueron sintetizadosmediante impregnación incipiente. Los tratamientos Fenton y deadsorción fueron realizados en un reactor Batch, concentración de 10mgL-1 de los colorantes, 0,25 mgmL-1 de catalizador, pH=3,7, 20±2ºC, 750 rpm y presión atmosférica. El carbón activado empleadocomo soporte presentó alta basicidad, presencia de grupos polares ensuperficie, alto contenido de cenizas (22,85%) y de oxígeno (43,93%)y fue mayoritariamente microporoso con un área superficial BETde 520 m2g-1. La máxima remoción lograda para el negro reactivo 5se obtuvo con el catalizador de 3% Fe (98,33%) luego de 180 min.mientras que para el cristal violeta se obtuvo con el catalizador de1% de Fe (63,95%) después de 180 min. La remoción mediante eltratamiento Fenton fue dependiente del contenido de Fe, tamaño departícula del sitio activo y del tipo de colorante. La remoción de negroreactivo 5 alcanzó un máximo con 3% de Fe mientras que para elcristal violeta disminuyó con el incremento del contenido de Fe. Eltratamiento planteado en el presente trabajo es promisorio para laeliminación de colorantes sintéticos presentes en aguas contaminadas...
Fe2O3-catalysts (0-10% m/mof Fe) supported on activated carbon obtained fromrose remnants were used to study the removal of dyesreactive black 5 and crystal violet by the Fenton reaction.The activated carbon was obtained from pyrolysis at 500°C (1h) followed by activation with NaOH (1:2 wt.). Thesupport was classified using several chemical and physicaltechniques. Fe-catalysts were synthesized by incipientimpregnation. Fenton and adsorption treatments wereperformed in a batch reactor, concentration of dye of10 mgL-1, 0.25 mgmL-1 catalyst, pH = 3.7, 20 ± 2 ° C,750 rpm and atmospheric pressure. The activated carbonused as support showed high basicity, presence of polargroups on the surface, high ash content (22.85%) andoxygen (43.93%) and was mostly of the microporoustype with a BET surface area of 520 m2g-1. The maximumdiscoloration achieved for black reactive 5 was obtainedwith the catalyst of 3% Fe (98.33%) after 180 min. whilefor the crystal violet it was obtained with the catalyst of1% Fe (63.95%) after 180 min. Discoloration by Fentontreatment is dependent on the Fe content, the particlesize of the active site and the type of dye. The removalof reactive black 5 reached a maximum at 3% Fe whilethe crystal violet decreased by increasing Fe content. Thetreatment proposed in this paper is promising for theremoval of synthetic dyes present in contaminated water...
Se estudo a remoção de corantes violeta de cristal e reativopreto 5 pela reação de Fenton utilizando diferentes concentraçõesdos catalisadores de Fe2O3 (0-10% m/m de Fe) suportados em carvãoativado obtido a partir de resíduos de rosas. O carvão ativado foiobtido por pirólise a 500 °C (1h) seguido por ativação com NaOH(1:2 em peso). O suporte foi caracterizado utilizando diferentestécnicas químicas e físicas. Os catalisadores de Fe foram sintetizadospor impregnação incipiente. Os tratamentos de adsorçao e de Fentonforam realizados num reator batch, com concentração de 10 mgL-1de corante, 0,25 mgmL-1 de catalisador, em pH = 3,7, 20 ± 2 °C,750 rpm e pressão atmosférica. O carvão ativado usado comosuporte mostrou basicidade elevada, a presença de grupos polaresna superfície, elevado teor de cinzas (22,85%) e oxigênio (43,93%) efoi principalmente microporoso com uma área de superfície BET de520 m2g-1. O valor máximo obtido para a descoloração reativo preto5 foi obtido com o catalisador de 3% Fe (98,33%) após 180 min.Enquanto para o violeta de cristal foi obtido com o catalisador de 1%Fe (63,95%) após 180 min. A descoloração por tratamento de Fentoné dependente do teor de Fe, tamanho de partícula do sítio ativo e dotipo de corante. A remoção de preto reativo 5 atinge um máximo emFe3%, enquanto que para o violeta de cristal diminui com o aumentodo teor de Fe. O tratamento proposto neste trabalho é promissorpara a remoção de corantes sintéticos presentes na água contaminada...
