腎と骨代謝 Vol.25 No.2(4)


特集名 破骨細胞の機能とその異常
題名 破骨細胞が造る酸性環境と骨痛
発刊年月 2012年 03月
著者 米田 俊之 大阪大学大学院歯学研究科生化学講座
【 要旨 】 骨痛はさまざまな骨疾患に合併するが,がんの骨転移にもっとも高頻度にみられ,患者のQOLを著しく損ない,しばしば死期を早める.骨痛のメカニズムや実体は不明であるが,作用機序の異なる破骨細胞阻害薬が骨痛に対して効果を示すことから,破骨細胞の関与が示唆される.破骨細胞は骨を吸収する際にプロトンを放出するが,骨に終末する痛覚神経にはプロトンを感受する酸感受性受容体が存在し,プロトンによるその活性化とそれに続く神経細胞内シグナルの賦活化が骨痛誘発に関与することが明らかとなりつつある.
Theme Functions of osteoclasts and their abnormality
Title Role of acidic microenvironments created by osteoclasts in bone pain
Author Toshiyuki Yoneda Department of Biochemistry, Osaka University Graduate School of Dentistry
[ Summary ] Bone pain is one of the most frequent complications associated with cancer metastasis to the bones and is a major cause of increased morbidity and mortality. The precise mechanisms related to bone pain are still poorly understood. However, clinical observations that the inhibitors of osteoclastic bone resorption, with distinct mechanisms of action, significantly reduce bone pain strongly suggest that osteoclasts play a critical role in causing bone pain. The acid-sensing receptors expressed on nociceptive sensory neurons innervating bone tissue are activated by protons released from bone-resorbing osteoclasts, followed by propagation of intracellular signaling pathways in sensory neuronal cells, leading to transduction of bone pain signals to the brain. These results suggest that inhibition of these events would be a mechanism-based intervention for the treatment of cancerinduced bone pain.
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