Department of Oral & Maxillofacial Surgery, Institute of Oral Biology, School of Dentistry, Kyung Hee University, Seoul, Republic of Korea.
Clin Oral Investig. 2012 Aug;16(4):1153-9. doi: 10.1007/s00784-011-0614-z. Epub 2011 Sep 22.
Bisphosphonates have been known to suppress osteoclast activity, survival, and recruitment. In this study, we tested effects of BPs on expression of two critical genes for osteoclastogenesis, M-CSF, and OPG in the process of osteoblast differentiation from hMSC. (1) The cells were cultured in osteogenic induction medium together with 0 (control group) and 10-8 M alendronate, pamidronate for up 2 and 3 weeks (for real-time PCR) and 3 and 4 weeks (for ELISA). (2) The real-time PCR protocol for M-CSF, OPG, and glyceraldehyde 3-phosphate dehydrogenase (GAPDH) consist of 40 cycles. (3) Enzyme-linked immunosorbent assay (ELISA): the amounts of M-CSF and OPG in the culture medium were determined using commercially available ELISA kits for M-CSF and OPG. Treatment of differentiating cells with alendronate or pamidronate, nitrogen-containing BPs increase the expression of OPG, which suppresses osteoclastogenesis, whereas it decreases the expression of M-CSF, which enhances preosteoclast formation. These results suggest a new mechanism by which BPs inhibit osteoclastogenesis. Results support hypothesis that progressive accumulation of bisphosphonate in jaws causes imbalance in osteogenesis and bone absorption and collateral osteoclast-osteoblast interaction. Bisphosphonate-related osteonecrosis of jaw (BPONJ) is one of the most serious complications of bisphosphonate (BP) therapy. However, the mechanism behind the this process of BPONJ is still unclear and there are so many hypotheses. Among many hypotheses, we focused on osteoclast-osteoblast interaction in this study. The findings of this study show new light on the present BPONJ occurrence theory based on the osteoclastic activity of BPs. Also, a more advanced and developed theory for BRONJ occurrence may be obtained by combining the osteoclast inhibition mechanism and the effects on osteoblastic differentiation by BPs.
双膦酸盐已知可抑制破骨细胞的活性、存活和募集。在这项研究中，我们测试了双膦酸盐对人骨髓间充质干细胞成骨分化过程中两个关键破骨细胞生成基因（M-CSF 和 OPG）表达的影响。（1）细胞在成骨诱导培养基中培养，同时加入 0（对照组）和 10-8 M 阿伦膦酸盐、帕米膦酸盐，培养 2 和 3 周（用于实时 PCR）和 3 和 4 周（用于 ELISA）。（2）M-CSF、OPG 和甘油醛 3-磷酸脱氢酶（GAPDH）的实时 PCR 方案包括 40 个循环。（3）酶联免疫吸附测定（ELISA）：使用市售的 M-CSF 和 OPG ELISA 试剂盒测定培养基中 M-CSF 和 OPG 的含量。用阿伦膦酸盐或帕米膦酸盐处理分化细胞，氮双膦酸盐增加了抑制破骨细胞生成的 OPG 的表达，而降低了促进前破骨细胞形成的 M-CSF 的表达。这些结果提示了双膦酸盐抑制破骨细胞生成的新机制。结果支持这样一种假说，即双膦酸盐在颌骨中的逐渐积累导致成骨和骨吸收失衡，并产生破骨细胞-成骨细胞的相互作用。双膦酸盐相关性颌骨坏死（BPONJ）是双膦酸盐（BP）治疗最严重的并发症之一。然而，BPONJ 发生的机制仍不清楚，有很多假说。在众多假说中，我们在这项研究中专注于破骨细胞-成骨细胞的相互作用。这项研究的发现为基于双膦酸盐的破骨细胞活性的现有 BPONJ 发生理论提供了新的启示。此外，通过结合双膦酸盐对成骨细胞分化的抑制机制和对其的影响，可能获得更先进和完善的 BRONJ 发生理论。
