Titanium surface roughness alters responsiveness of MG63 osteoblast-like cells to 1?,25-(OH)2D3

Abstract

Surface roughness has been shown to affect differentiation and local factor production of MG63 osteoblast-like cells. This study examined whether surface roughness alters cellular response to circulating hormones such as 1 alpha,25-(OH)2D3. Unalloyed titanium (Ti) disks were pretreated with HF/HNO3 (PT) and then were machined and acid-etched (MA). Ti disks also were sandblasted (SB), sandblasted and acid etched (CA), or plasma sprayed with Ti particles (PS). The surfaces, from smoothest to roughest, were: PT, MA, CA, SB, and PS. MG63 cells were cultured to confluence on standard tissue culture polystyrene (plastic) or the Ti surfaces and then treated for 24 h with either 10(-8) M or 10(-7) M 1 alpha,25-(OH)2D3 or vehicle (control). Cellular response was measured by assaying cell number, cell layer alkaline phosphatase specific-activity, and the production of osteocalcin, latent (L) TGF beta, and PGE2. Alkaline phosphatase activity was affected by surface roughness; as the surface became rougher, the cells showed a significant increase in alkaline phosphatase activity. Addition of 1 alpha,25-(OH)2D3 to the cultures caused a dose-dependent stimulation of alkaline phosphatase activity that was synergistic with the effect caused by surface roughness alone. 1 alpha,25-(OH)2D3 also caused a synergistic increase in osteocalcin production as well as local factor (LTGF beta and PGE2) production on the rougher CA, SB, and PS surfaces, but it had no effect on the production on smooth surfaces. The inhibitory effect of surface roughness on cell number was not affected by 1 alpha,25-(OH)2D3 except on the SB surface. 1 alpha,25-(OH)2D3 decreased cell number, increased alkaline phosphatase activity and osteocalcin production, and had no effect on LTGF beta or PGE2 production by MG63 cells grown on tissue culture polystyrene. These data suggest that bone cell response to systemic hormones is modified by surface roughness and that surface roughness increases the responsiveness of MG63 cells to 1 alpha,25-(OH)2D3. They also suggest that the endocrine system is actively involved in normal bone healing around implants.

Pulsed electromagnetic fields enhance BMP‐2 dependent osteoblastic differentiation of human mesenchymal stem cells

“…At harvest, cell number was determined, and cultures were examined for expression of an osteoblastic phenotype by measuring ALP specific activity of cell layer lysates 31 and osteocalcin levels in the conditioned media using an immunoassay kit (Human Osteocalcin RIA Kit, Biomedical Technologies, Stoughton, MA). 32 Based on these results, 40 ng/ mL BMP-2 was selected to prime the MSCs along an osteoblast differentiation pathway.…”

“…36 Therefore, in addition to assessing ALP activity and osteocalcin, we measured levels of latent and active TGF-b1 in the conditioned media using an immunoassay kit (Promega Corp., Madison, WI), as well as the levels of PGE2 (NEN Research Products, Boston, MA). 32 In each experiment, each variable was tested in six separate cultures, which provided sufficient power to allow comparison of absolute values rather than treatment/control ratios. Levels of osteocalcin, latent and active TGF-b1, and PGE2 in culture media were normalized to cell number in the cell layer from which the conditioned media were collected.…”

Sandblasted-acid-etched titanium surface influences in vitro the biologicalbehavior of SaOS-2 human osteoblast-like cells

“…More than macrostructural features, the superficial layer of titanium-oxide and the implant surface microstructure seem to deeply affect bone/fixture interactions [11][12][13] . Many studies 8,10,11,[14][15][16][17][18][19][20][21][22] have shown that a rough surface, when compared to a relatively smooth one, grants better biomolecular adsorption, increases extracellular matrix production and promotes the differentiation of the mesenchymal cells toward an osteoblastic phenotype. Cells may be able to detect variations of the superficial geometry through focal contact mechanisms thus regulating their own phenotypical expression.…”

“…Several primary and transformed cell lines have been used to develop culture systems to study the interaction of cells with implant biomaterials 8,14,[17][18][19][36][37][38][39][40][41][42][43][44][45][46] . SaOS-2 is an osteoblast-like cell line, derived from a human osteosarcoma, that several studies have demonstrated to be a relevant cell model, due to its large analogies with immature osteoblast cells [38][39][40][41]47) and better manageability when compared to primary human cell Sandblasted-acid-etched titanium surface influences in vitro the biological behavior of SaOS-2 human osteoblast-like cells culture 43) .…”

Pretreatment of bone with osteoclasts affects phenotypic expression of osteoblast‐like cells

“…When MG63 human osteoblastlike osteosarcoma cells [5], fetal rat calvarial cells [24], or normal human osteoblast cells (NHOst) [25] are cultured on titanium disks with varying microtopographies, there is a roughness-dependent effect on phenotypic expression. As roughness increases, proliferation decreases.…”