Bone Abstracts

The integration of biomaterials into the calcified bone tissue is essential for the clinical success of bone implants. A particular strategy to improve such integration is the use of specific molecules to increase osteoblast cell adhesion, proliferation, and/or differentiation on the surface of the implants, aiming to enhance the interaction of cells with biomaterials. The goal of this study was to better understand the potential of the anti-osteoporotic drug strontium ranelate for improving the efficacy of bone implants. We analyzed direct effects of the drug on the interaction of osteoblast cells with different titanium substrates in cell culture. Cells were treated with 0.12 and 0.5 mM Sr²⁺ of strontium ranelate and cell response to the drug was evaluated on four pure titanium substrates with different surface topographies. After 24 h in culture, treatment preserved cell morphology parameters (area, aspect ratio, circularity, and solidity) and the orientation of cells on grooved substrates, in which they were preferentially aligned with the direction of the grooves. The initial cell adhesion to the substrates after 4 h was also not changed by treatment. We found, however, that both concentrations of the drug significantly (P<0.05) increased cell proliferation rates in all substrates, especially from 7 to 21 days in culture. Moreover, we found a significant (P<0.05) dose-dependent increase in alkaline phosphatase activity after 21 days and in the formation of mineralized matrix after 28 days. This matrix resembled that described in native bone. In conclusion, we show that strontium ranelate improved the interaction of osteoblast cells with different titanium substrates, increasing cell proliferation and differentiation into mature osteoblasts and the formation of bone-like mineralized matrix in all substrates. We believe our results highlight a promising role of strontium ranelate for enhancing the clinical success of bone implants, especially in elderly patients with osteoporosis.