Tanaka Makoto, Mori Hiroshi, Kayasuga Ryoji, Kawabata Kazuhito
Research Promotion, Ono Pharmaceutical Co., Ltd, 3-1-1, Sakurai, Shimamoto-cho, Mishima-gun Osaka, 618-8585 Japan.
Discovery Research Laboratories, Ono Pharmaceutical Co., Ltd, Shimamoto-cho, Mishima-gun Osaka, 618-8585 Japan.
Springerplus. 2015 Feb 3;4:59. doi: 10.1186/s40064-015-0848-3. eCollection 2015.
An increase of serum creatine kinase (CK) has been observed in clinical studies of nitrogen-containing aminobisphosphonates (N-BPs). Osteoclasts are thought to be the source of the CK, but there is no clear evidence for the hypothesis. In this study, CK release from rabbit osteoclasts induced by N-BPs was examined in an in vitro culture system. Rabbit bone-derived cells were cultured for 3 days on the N-BPs pretreated cortical bone slices. CK activity in the culture medium was measured at 3 days of culture. The CK activity was increased with all N-BPs at concentrations at which showed antiresorptive activity over 60% inhibition of C-terminal cross-linking telopeptide of type I collagen (CTX-1) release. The maximum induction of CK activity was 2.6 times the control level. The lowest N-BP concentration inducing CK release was 3 times lower than that required to decrease the osteoclast number. Bafilomycin A1, an inhibitor of vacuolar H(+)-ATPase, abrogated all N-BP actions, including CK release. Bone-derived cells except osteoclasts were insensitive to bafilomycin A1, suggesting that osteoclasts were the source of CK. Regarding the time course, CK release occurred after a 1 day lag time and increased steadily until day 3 of culture. These results show that CK release is induced by N-BPs from osteoclasts at concentrations at which N-BPs show antiresorptive activity over 60% inhibition of CTX-1 release in vitro. These findings explain the mechanism of the CK increase induced by clinical use of N-BPs.
在含氮氨基双膦酸盐（N-BPs）的临床研究中，已观察到血清肌酸激酶（CK）升高。破骨细胞被认为是CK的来源，但这一假说尚无明确证据。在本研究中，在体外培养系统中检测了N-BPs诱导兔破骨细胞释放CK的情况。将兔骨来源的细胞在经N-BPs预处理的皮质骨切片上培养3天。在培养3天时测量培养基中的CK活性。所有N-BPs在对I型胶原C端交联端肽（CTX-1）释放具有超过60%抑制作用的抗吸收活性浓度下，CK活性均升高。CK活性的最大诱导倍数为对照水平的2.6倍。诱导CK释放的最低N-BP浓度比减少破骨细胞数量所需的浓度低3倍。液泡H(+)-ATP酶抑制剂巴弗洛霉素A1消除了所有N-BP的作用，包括CK释放。除破骨细胞外的骨来源细胞对巴弗洛霉素A1不敏感，提示破骨细胞是CK的来源。关于时间进程，CK释放在1天的延迟时间后发生，并在培养第3天前稳定增加。这些结果表明，在体外N-BPs对CTX-1释放具有超过60%抑制作用的抗吸收活性浓度下，N-BPs可诱导破骨细胞释放CK。这些发现解释了临床使用N-BPs诱导CK升高的机制。
