Resumen de MLO-Y4 cells modulate human peripheral blood mononuclear cells migration
D. Aedo Martín, José Adolfo Orellana Gómez-Rico, I. Buendía, F.J. Areta Jiménez, Juan Antonio Ardura Rodríguez, A. Rodríguez de Gortázar
Osteocytes, the most abundant cell type in bone, are buried in the mineralized bone matrix but regulate bone remodeling by altering osteoblast and osteoclast function. The aim of the present study was to evaluate the response of peripheral blood mononuclear cells from patients with osteoporotic and non-osteoporotic fracture, to the factors secreted by MLO-Y4 osteocytic cells under static or mechanical conditions. We obtained 12ml of peripheral blood of non-osteoporotic patients older than 18 years with traumatic fracture of long bones and osteoporotic patients with hip fracture. Patients in treatment for osteoporosis, with a secondary osteoporosis state or a tumoral process were excluded from the study. The population was recruited in the last year in the Hospital Central de la Defensa Gómez Ulla (Madrid, Spain). Eighteen valid samples were obtained. 14 (78%) presented osteoporotic fracture and 4 (22%) presented traumatic long bone fracture without osteoporosis. We obtained the peripheral blood mononuclear cells and we evaluated their capacity to migrate under the presence of conditioned media from osteocytic cells. MLO-Y4 cells were subjected or not (static control) to mechanical stimulation by fluid flow (FF, 10 dyn/cm2, 15 min). Cell medium was changed and cells were cultured for additional 18 h and the conditioned medium (CM) was then collected. The migration assays were performed in Costar transwell cell culture chamber inserts (Corning Costar Corporation, Cambridge, MA) with an 8 ?m pore size. Briefly, 5×104 cells were placed on the upper chamber in 20% of MLO-Y4 CM. After 6 hours, cells on the underside of the Transwell were fixed, stained with Crystal Violet and counted. We observed that CM from static MLO-Y4 cells increased monocyte migration (20.93%). In contrast, CM from mechanically stimulated MLO-Y4 cells inhibited monocyte migration (53.98%). The CM from static condition cells favored the migration of monocytic cells (p<0.001) with a correlation coefficient of 88%. The linear correlation coefficient of the regression line was 92%. The CM from mechanically stimulated cells inhibited the migration (p<0.001) with a correlation coefficient of 79.2%. The linear correlation coefficient of the regression line was 58.8%. Our present data indicates that human monocytic cells can respond to factors secreted by MLO-Y4 cells modulating their migration.
