Increased calcium content and inhomogeneity of mineralization render bone toughness in osteoporosis: Mineralization, morphology and biomechanics of human single trabeculae
Increased calcium content and inhomogeneity of mineralization render bone toughness in osteoporosis: Mineralization, morphology and biomechanics of human single trabeculae
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DOI：
10.1016/j.bone.2009.08.002
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发表时间：
2009-12-01
期刊：
影响因子：
4.1
通讯作者：
Amling, Michael
中科院分区：
文献类型：
--
作者：
Busse, Bjoern;Hahn, Michael;Amling, Michael
矿物质含量和/或形态对骨质量的影响的差异和程度在很大程度上仍然没有答案，这是由于空间测量领域中的几种微结构特性（例如，力传递、轨迹、微愈伤组织）。因此，作为松质骨的最小基本成分，我们专注于单个骨小梁，以研究矿化和结构的影响，包括独立和叠加。在尸检时从20名女性中获得经髂骨Bordier骨芯和T12椎骨用于标本制备，从而能够进行X线摄影分析、组织形态测定、骨矿物质密度分布（BMDD）分析和小梁单一化。根据骨折外观和骨体积（BV/TV），评价了椎体骨折病例的接触X线和组织形态学限值，产生了两个亚类，椎体骨折（n=12，空组78岁）和非椎体骨折（n=8，空组49岁）病例。测量小梁数量（Tb.N.），小梁分离（Tb.Sp.），骨小梁厚度（Tb.Th.），进行骨小梁模式因子（TBPf）和侵蚀表面（ES/BS）以提供所研究组的详细结构特性。通过三点弯曲评估的400个杆状单椎体小梁的力学性能与通过横截面杆状和板状小梁的BMDD分析量化的矿物性能相匹配，无论是叠加还是独立。非骨质疏松的髂嵴和椎骨表现出对结构参数的线性依赖性，而骨质疏松的隔间被证明与骨结构无关。独立于骨小梁厚度，钙化棒状骨小梁显示杨氏模量、断裂载荷、屈服强度、极限应力、失效功和弯曲刚度降低，沿着平均钙含量和钙宽度显著增加。非骨化性骨小梁由于矿化结构均匀而表现出生物力学有益特性，而骨化性骨小梁主要表现出各种矿化骨包、侵蚀表面、高矿化骨水泥线和微裂纹。单个骨小梁的杨氏模量与骨小梁厚度呈显著负相关。由于钙含量增加，但分布不均匀，骨质疏松小梁可能会受到剪切应力，使骨变得脆弱，超出由于裂缝和腔隙引起的结构损伤。(C)2009 Elsevier Inc. All rights reserved.
The differentiation and degree of the effects of mineral content and/or morphology on bone quality remain, to a large extent, unanswered due to several microarchitectural particularities in spatial measuring fields (e.g., force transfer, trajectories, microcalli). Therefore, as the smallest basic component of cancellous bone, we focused on single trabeculae to investigate the effects of mineralization and structure, both independently and in superposition. Transiliac Bordier bone cores and T12 vertebrae were obtained from 20 females at autopsy for specimen preparation, enabling radiographical analyses, histomorphometry, Bone Mineral Density Distribution (BMDD) analyses, and trabecular singularization to be performed. Evaluated contact X-rays and histomorphometric limits from cases with osteoporotic vertebral fractures generated two subdivisions, osteoporotic (n=12, empty set 78 years) and non-osteoporotic (n=8, empty set 49 years) cases, based on fracture appearance and bone volume (BV/TV). Measurements of trabecular number (Tb.N.), trabecular separation (Tb.Sp.), trabecular thickness (Tb.Th.), trabecular bone pattern factor (TBPf) and eroded surface (ES/BS) were carried out to provide detailed structural properties of the investigated groups. The mechanical properties of 400 rod-like single vertebral trabeculae, assessed by three-point bending, were matched with mineral properties as quantified by BMDD analyses of cross-sectioned rod-like and plate-like trabeculae, both in superposition and independently. Non-osteoporotic iliac crests and vertebrae displayed linear dependency on structure parameters, whereas osteoporotic compartments proved to be non-correlated with bone structure. Independent of trabecular thickness, osteoporotic rod-like trabeculae showed decreases in Young's modulus, fracture load, yield strength, ultimate stress, work to failure and bending stiffness, along with significantly increased mean calcium content and calcium width. Non-osteoporotic trabeculae showed biomechanically beneficial properties due to a homogeneous mineralization configuration, whereas osteoporotic trabeculae predominantly demonstrated various mineralized bone packets, eroded surfaces, highly mineralized cement lines and microcracks. The Young's moduli of single trabeculae exhibited significantly negative linear correlations with trabecular thickness. Because of increased, but inhomogeneously distributed, calcium content, osteoporotic trabeculae may be subject to shear stresses that render bone fragile beyond structure impairment due to cracks and lacunae. (C) 2009 Elsevier Inc. All rights reserved.