Thammasat University Research Unit in Dental and Bone Substitute Biomaterials, Faculty of Dentistry, Thammasat University, Pathumthani, Thailand.
Thammasat University, Faculty of Dentistry, Pathumthani, Thailand.
J Appl Oral Sci. 2024 Aug 12;32:e20240034. doi: 10.1590/1678-7757-2024-0034. eCollection 2024.
Bisphosphonates are prescribed to treat excessive bone resorption in patients with osteoporosis. However, its use is associated with potential adverse effects such as medication-related osteonecrosis of the jaw, prompting the introduction of the drug holiday concept in patients prior to dentoalveolar surgery. Furthermore, bisphosphonate discontinuation has been studied in vivo, in humans, and in animal models. However, it is not known whether this approach could affect bone cells in vitro. Therefore, the objective of this study was to investigate the potential effects of bisphosphonate discontinuation on pre-osteoblast and osteoblast activities in vitro.
Pre-osteoblasts (MC3T3) and osteoblasts were treated with bisphosphonate (alendronate) at concentrations of 1, 5, and 10 µM. Alendronate was then withdrawn at different time points. The negative control consisted of untreated cells (0 µM), while the positive control consisted of cells incubated with alendronate throughout the experiment. Cell viability, cell adhesion, cell cytoskeleton, mineralization, and gene expressions were investigated.
Pre-osteoblasts and osteoblasts showed a decrease in cell viability after treatment with 5-10 μM alendronate for 4 days or longer. Two days of alendronate discontinuation significantly increased cell viability compared with the positive control. However, these levels did not reach those of the negative control. Bone nodule formation was reduced by alendronate. Discontinuation of alendronate regained bone nodule formation. Longer periods of discontinuation were more effective in restoring nodule formation than shorter periods. Addition of alendronate resulted in an increase in the percentage of dead cells, which, in turn, decreased when alendronate was discontinued. Alendronate affected the cell cytoskeleton by disassembling actin stress fibers. Cell adhesion and cell morphological parameters were also affected by alendronate. Discontinuation of alendronate restored cell adhesion and these parameters. Overall, the highest improvement after alendronate discontinuation was seen at 10 µM. However, alendronate treatment and discontinuation did not affect osteoblast gene expression.
Discontinuation of alendronate helps to reverse the negative effects of the drug on cell viability, cell adhesion, and mineralization by restoring the cell cytoskeleton. Our data suggest the benefits of drug holiday and/or intermittent strategies for alendronate administration at the cellular level.
双膦酸盐用于治疗骨质疏松症患者的过度骨吸收。然而，其使用与潜在的不良反应相关，例如药物相关的颌骨坏死，这促使在牙牙槽手术前引入药物假期概念。此外，双膦酸盐的停药已在体内、人类和动物模型中进行了研究。然而，尚不清楚这种方法是否会影响体外的骨细胞。因此，本研究的目的是研究双膦酸盐停药对体外前成骨细胞和成骨细胞活性的潜在影响。
用双膦酸盐（阿仑膦酸钠）以 1、5 和 10 µM 的浓度处理前成骨细胞（MC3T3）和成骨细胞。然后在不同的时间点去除阿仑膦酸钠。阴性对照由未处理的细胞（0 µM）组成，阳性对照由整个实验中用阿仑膦酸钠孵育的细胞组成。研究了细胞活力、细胞黏附、细胞细胞骨架、矿化和基因表达。
用 5-10 µM 阿仑膦酸钠处理 4 天或更长时间后，前成骨细胞和成骨细胞的细胞活力下降。与阳性对照相比，停用阿仑膦酸钠两天可显著增加细胞活力。然而，这些水平并未达到阴性对照的水平。骨结节形成减少。阿仑膦酸钠的停用恢复了骨结节的形成。与较短的停药时间相比，较长的停药时间更有效地恢复结节形成。添加阿仑膦酸钠会导致死细胞的百分比增加，而当阿仑膦酸钠停止使用时，死细胞的百分比又会减少。阿仑膦酸钠通过分解肌动蛋白应力纤维来影响细胞细胞骨架。细胞黏附和细胞形态学参数也受到阿仑膦酸钠的影响。阿仑膦酸钠的停用恢复了细胞黏附和这些参数。总的来说，在 10 µM 时，阿仑膦酸钠停药后改善程度最高。然而，阿仑膦酸钠治疗和停药并不影响成骨细胞基因表达。
通过恢复细胞细胞骨架，阿仑膦酸钠的停药有助于逆转药物对细胞活力、细胞黏附和矿化的负面影响。我们的数据表明，在细胞水平上，药物假期和/或间歇性阿仑膦酸钠给药策略是有益的。
