Otto Sven, Pautke Christoph, Opelz Christine, Westphal Ines, Drosse Inga, Schwager Joanna, Bauss Frieder, Ehrenfeld Michael, Schieker Matthias
Department of Oral- and, Maxillofacial Surgery, Ludwig-Maximilians-University, Munich, Germany.
J Oral Maxillofac Surg. 2010 Nov;68(11):2837-45. doi: 10.1016/j.joms.2010.07.017.
Osteonecrosis of the jaw has been reported in patients receiving high doses of intravenous nitrogen-containing bisphosphonates (N-BPs) because of malignant disease. The exact pathomechanisms have been elusive and questions of paramount importance remain unanswered. Recent studies have indicated toxic effects of bisphosphonates on different cell types, apart from osteoclast inhibition. Multipotent stem cells play an important role in the processes of wound healing and bone regeneration, which seem to be especially impaired in the jaws of patients receiving high doses of N-BPs. Therefore, the aim of the present study was to investigate the effects of different bisphosphonate derivatives and dose levels combined with varying pH levels on the mesenchymal stem cells in vitro.
The effect of 2 N-BPs (zoledronate and ibandronate) and 1 non-N-BP (clodronate) on immortalized mesenchymal stem cells was tested at different concentrations, reflecting 1, 3, and 6 months and 1, 3, 5, and 10 years of exposure to standard oncology doses of the 2 N-BPs and equimolar concentrations of clodronate at different pH values (7.4, 7.0, 6.7, and 6.3). Cell viability and activity were analyzed using a WST assay. Cell motility was investigated using scratch wound assays and visualized using time-lapse microscopy.
Both types of bisphosphonates revealed remarkable differences. Zoledronate and ibandronate showed a dose- and pH-dependent cellular toxicity. Increasing concentrations of both N-BPs and an acidic milieu led to a significant decrease in cell viability and activity (P < .01), with more pronounced effects for zoledronate. Equimolar concentrations of clodronate did not affect the cell survival or activity significantly, apart from the effect of pH reduction itself, which was also detectable in the patients in the control group who did not receive bisphosphonates.
Our results have shown that high concentrations of N-BPs and a local acidic milieu, which is commonly present in infections of the jaw, might play a key role in the pathogenesis of osteonecrosis of the jaw in patients receiving high doses of N-BPs for malignant diseases. Also the potency of N-BPs might be different, suggesting a greater risk of osteonecrosis of the jaw with zoledronate.
有报道称，因恶性疾病接受高剂量静脉注射含氮双膦酸盐（N - BPs）的患者会发生颌骨坏死。确切的发病机制尚不清楚，一些至关重要的问题仍未得到解答。最近的研究表明，双膦酸盐除了抑制破骨细胞外，对不同细胞类型也有毒性作用。多能干细胞在伤口愈合和骨再生过程中起重要作用，而在接受高剂量N - BPs的患者颌骨中，这些过程似乎尤其受损。因此，本研究的目的是在体外研究不同双膦酸盐衍生物、剂量水平以及不同pH值对间充质干细胞的影响。
测试了2种N - BPs（唑来膦酸和伊班膦酸）和1种非N - BPs（氯膦酸）在不同浓度下对永生化间充质干细胞的影响，这些浓度反映了2种N - BPs标准肿瘤学剂量以及氯膦酸等摩尔浓度在1、3和6个月以及1、3、5和10年暴露后的情况，pH值分别为7.4、7.0、6.7和6.3。使用WST试验分析细胞活力和活性。使用划痕试验研究细胞迁移，并通过延时显微镜观察。
两种双膦酸盐显示出显著差异。唑来膦酸和伊班膦酸表现出剂量和pH依赖性细胞毒性。N - BPs浓度增加以及酸性环境导致细胞活力和活性显著降低（P <.01），唑来膦酸的影响更明显。氯膦酸等摩尔浓度除了降低pH本身的影响外，对细胞存活或活性没有显著影响，在未接受双膦酸盐的对照组患者中也可检测到pH降低的影响。
我们的结果表明，高浓度的N - BPs和颌骨感染中常见的局部酸性环境，可能在因恶性疾病接受高剂量N - BPs治疗的患者颌骨坏死发病机制中起关键作用。此外，N - BPs的效力可能不同，提示唑来膦酸导致颌骨坏死的风险更高。
