abstract
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.
keywords
MESENCHYMAL STEM-CELLS; IN-VITRO; NANOPHASE HYDROXYAPATITE; COLLOIDAL GELS; BONE; PARTICLES; PROLIFERATION; NANO; CYTOTOXICITY; EXPRESSION
subject category
Science & Technology - Other Topics; Materials Science
authors
Costa-Rodrigues, J; Silva, A; Santos, C; Almeida, MM; Costa, ME; Fernandes, MH
our authors
Groups
G2 - Photonic, Electronic and Magnetic Materials
G5 - Biomimetic, Biological and Living Materials
acknowledgements
Finantial support by Faculdade de Medicina Dentaria, Universidade do Porto, Portugal. CLSM observation was performed at Advanced Light Microscopy, IBMC, University of Porto (IBMC.INEB) under the responsibility of Dr. Paula Sampaio.