Topography Influences Adherent Cell Regulation of Osteoclastogenesis

The importance of osteoclast-mediated bone resorption in the process of osseointegration has not been widely considered. in this study,cell culture was used to investigate the hypothesis that the function of implant-adherent bone marrow stromal cells (bmscs) in osteoclastogenesis is influenced by surface topography. bmscs isolated from femur and tibia of sprague-dawley rats were seeded onto 3 types of titanium surfaces (smooth,micro,and nano) and a control surface (tissue culture plastic) with or without osteogenic supplements. after 3 to 14 d,conditioned medium (cm) was collected. subsequently,rat bone marrow-derived macrophages (bmms) were cultured in media supplemented with soluble receptor activator of nf-ligand (rankl) and macrophage colony-stimulating factor (m-csf) as well as bmsc cm from each of the 4 surfaces. gene expression levels of soluble rankl,osteoprotegerin,tumor necrosis factor α,and m-csf in cultured bmscs at different time points were measured by real-time polymerase chain reaction. the number of differentiated osteoclastic cells was determined after tartrate-resistant acid phosphatase staining. analysis of variance and t test were used for statistical analysis. the expression of prominent osteoclast-promoting factors tumor necrosis factor α and m-csf was increased by bmscs cultured on both micro- and nanoscale titanium topographies (p < 0.01). bmsc cm contained a heat-labile factor that increased bmms osteoclastogenesis. cm from both micro- and nanoscale surface-adherent bmscs increased the osteoclast number (p < 0.01). difference in surface topography altered bmsc phenotype and influenced bmm osteoclastogenesis. local signaling by implant-adherent cells at the implant-bone interface may indirectly control osteoclastogenesis and bone accrual around endosseous implants. © international & american associations for dental research 2016.