Department of Anatomy & Cell Biology, Indiana University School of Medicine, Indianapolis, 46202, USA.
Bone. 2011 Jul;49(1):56-65. doi: 10.1016/j.bone.2010.10.159. Epub 2010 Oct 16.
The bisphosphonates (BPs) have been useful tools in our understanding of the role that bone remodeling plays in skeletal health. The purpose of this paper is to outline what we know, and what is still unknown, about the role that BPs play in modulating bone turnover, how this affects microdamage accumulation, and ultimately what the effects of these changes elicited by BPs are to the structural and the material biomechanical properties of the skeleton. We know that BPs suppress remodeling site-specifically, probably do not have a direct effect on formation, and that the individual BPs vary with respect to speed of onset, duration of effect and magnitude of suppression. However, we do not know if these differences are meaningful in a clinical sense, how much remodeling is sufficient, the optimal duration of treatment, or how long it takes to restore remodeling to pre-treatment levels following withdrawal. We also know that suppression is intimately tied to microdamage accumulation, which is also site-specific, that BPs impair targeted repair of damage, and that they can reduce the energy absorption capacity of bone at the tissue level. However, the BPs are clearly effective at preventing fracture, and generally increase bone mineral density and whole bone strength, so we do not know whether these changes in damage accumulation and repair, or the mechanical effects at the tissue level, are clinically meaningful. The mechanical effects of BPs on the fatigue life of bone, or BP effects on bone subject to an impact, are entirely unknown. This paper reviews the literature on these topics, and identifies gaps in knowledge that can be addressed with further research.
双膦酸盐 (BPs) 在我们理解骨骼重塑在骨骼健康中的作用方面是非常有用的工具。本文旨在概述我们对 BPs 在调节骨转换中的作用、这如何影响微损伤积累以及最终 BPs 引起的这些变化对骨骼结构和材料生物力学特性的影响所了解和未知的内容。我们知道 BPs 特异性地抑制重塑,可能对形成没有直接影响,并且个体 BPs 在起始速度、作用持续时间和抑制程度方面存在差异。然而,我们不知道这些差异在临床意义上是否有意义,多少重塑是足够的,最佳治疗持续时间,或者在停止治疗后需要多长时间才能使重塑恢复到治疗前水平。我们还知道,抑制与微损伤积累密切相关,微损伤积累也是特异性的,BPs 会损害损伤的靶向修复,并且它们可以降低组织水平的骨能量吸收能力。然而,BPs 显然有效地预防骨折,并且通常会增加骨矿物质密度和整体骨强度,因此我们不知道在损伤积累和修复方面的这些变化,或者在组织水平上的机械影响,是否具有临床意义。BPs 对骨的疲劳寿命的机械影响,或 BPs 对受冲击的骨的影响,目前尚完全未知。本文回顾了这些主题的文献,并确定了可以通过进一步研究解决的知识空白。