RESUMEN

Nanosized hydroxyapatite (HA) is a promising material in clinical applications targeting the bone tissue. NanoHA is able to modulate bone cellular events, which accounts for its potential utility, but also raises safety concerns regarding the maintenance of the bone homeostasis. This work analyses the effects of HA nanoparticles (HAnp) on osteoclastic differentiation and activity, an issue that has been barely addressed. Rod-like HAnp, produced by a hydrothermal precipitation method, were tested on peripheral blood mononuclear cells (PBMC), which contains the CD14+ osteoclastic precursors, in unstimulated or osteoclastogenic-induced conditions. HAnp were added at three time-points during the osteoclastic differentiation pathway, and cell response was evaluated for osteoclastic related parameters. Results showed that HAnp modulated the differentiation and function of osteoclastic cells in a dose- and time-dependent manner. In addition, the effects were dependent on the stage of osteoclastic differentiation. In unstimulated PBMC, HAnp significantly increased osteoclastogenesis, leading to the formation of mature osteoclasts, as evident by the significant increase of TRAP activity, number of TRAP-positive multinucleated cells, osteoclastic gene expression and resorbing ability. However, in a population of mature osteoclasts (formed in osteoclastogenic-induced PBMC cultures), HAnp caused a dose-dependent decrease on the osteoclastic-related parameters. These results highlight the complex effects of HAnp in osteoclastic differentiation and activity, and suggest the possibility of HAnp to modulate/disrupt osteoclastic behavior, with eventual imbalances in the bone metabolism. This should be carefully considered in bone-related and other established and prospective biomedical applications of HAnp.

Asunto(s)

Durapatita/administración & dosificación , Nanopartículas/administración & dosificación , Osteoblastos/citología , Osteoblastos/fisiología , Osteoclastos/citología , Osteoclastos/fisiología , Adulto , Diferenciación Celular/efectos de los fármacos , Diferenciación Celular/fisiología , Proliferación Celular/efectos de los fármacos , Proliferación Celular/fisiología , Células Cultivadas , Relación Dosis-Respuesta a Droga , Humanos , Masculino , Nanopartículas/química , Nanopartículas/ultraestructura , Osteoblastos/efectos de los fármacos , Osteoclastos/efectos de los fármacos

RESUMEN

In our previous work we described the preparation and characterization of spray dried hydroxyapatite micro granules loaded with 5-fluorouracil (5-FU). These loaded particles are used as a model drug delivery system (DDS). In this study we examined the in vitro response of two cell lines derived from different tissues to 5-FU loaded granules (LG). Both cell lines, either L929 cells of a mouse fibroblast lineage or cells originating from a rat osteosarcoma (ROS 17/2.8) showed a dose dependent decrease in cell proliferation in response to 5-FU-, either dissolved in the culture medium or loaded onto particles. The response of the two cell lines to loaded and nonloaded particles was different. The effect of LG and of a corresponding concentration of free 5-FU was practically the same for the ROS 17/2.8 cells indicating that ROS 17/2.8 cells were not affected by the carrier material. In contrast, L929 cells showed a slight decrease in cell proliferation also in the presence of granules not loaded with 5-FU. This is thought to be attributed to the inhibition of mitogenesis by phosphocitrates, already demonstrated in fibroblasts. In summary, we found that the loaded 5-FU kept its effectivity after the spray drying process and that the response towards the granules varied with cell type. This is the first step towards a tissue specific DDS.

Asunto(s)

Proliferación Celular/efectos de los fármacos , Durapatita/química , Fluorouracilo/farmacología , Animales , Antimetabolitos Antineoplásicos/química , Antimetabolitos Antineoplásicos/farmacología , Línea Celular , Línea Celular Tumoral , Linaje de la Célula , Relación Dosis-Respuesta a Droga , Fibroblastos/citología , Fibroblastos/efectos de los fármacos , Fluorouracilo/química , Mesodermo/citología , Ratones , Microscopía Electrónica de Rastreo , Microesferas , Osteosarcoma/patología , Ratas

RESUMEN

Hydroxyapatite (HAP) particles with different morphologies were precipitated from homogeneous calcium/citrate/phosphate solutions at physiological temperature. Small variations of the starting solution pH in the range 7.4

Asunto(s)

Ácido Cítrico/química , Durapatita/química , Nanopartículas/química , Calcio/química , Concentración de Iones de Hidrógeno , Microscopía Electrónica de Rastreo , Tamaño de la Partícula , Fosfatos/química , Soluciones/química , Espectroscopía Infrarroja por Transformada de Fourier , Propiedades de Superficie , Temperatura , Difracción de Rayos X