The degree of mineralization is a determinant of bone strength: a study on human calcanei
The degree of mineralization is a determinant of bone strength: a study on human calcanei
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DOI：
10.1016/j.bone.2003.12.012
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发表时间：
2004-05-01
期刊：
影响因子：
4.1
通讯作者：
Meunier, PJ
中科院分区：
文献类型：
--
作者：
Follet, H;Boivin, G;Meunier, PJ
骨的强度取决于骨基质体积（BMV）、骨微结构以及骨的矿化程度（DMB）。我们最近在接受阿仑膦酸钠治疗的骨质疏松患者中发现，骨折风险降低，骨密度增加，由于延长的继发性矿化而导致DMB平行增加，但没有改变BMV或骨微结构。在组织水平上测量了20名受试者（年龄78 ± 8岁，8名女性，12名男性）尸检时采集的跟骨骨样本的DMB和强度，这些受试者突然死亡，无明显的骨病。在显微放射照片上测量的DMB参数（平均DMB、DMB分布、最常见的最大DMB值和半峰宽，反映DMB均匀性的指标）与43例人骨髂骨松质骨样本中报告的参数进行比较。还测量了微结构参数（TbTh，TbN和TbSp）的组织形态学测量。在通用螺钉驱动机器（Schenck RSA 250）上对相同跟骨的连续样本进行压缩测试。使用5000 N测力传感器（TME，F 501 TC）测量压缩载荷。使用由表观杨氏模量（E）、最大强度（σ max）和直至失效的功（W）开发的特定位移传感器直接在样品上测量位移。在人体松质骨组织中，跟骨的平均DMB（+/-SD）（1.135 +/- 0.147 g/cm（3））高于髂嵴（1.098 +/- 0.077 g/cm（3））。平均最频繁最大DMB值（平均DMB频率最大值）跟骨为1.118 +/- 0.175 g/cm（3），髂骨样本为1.108 +/- 0.095 g/cm（3），跟骨的DMB比髂骨样本更不均匀（半峰平均宽度分别为0.270 +/- 0.127和0.227 +/- 0.056 g/cm（3））。压缩试验表明，DMB与弹性模量（r（2）= 0.69）和最大强度（r（2）= 0.69）呈显著的正线性相关。即使调整了钙化骨体积、杨氏模量（E）、最大强度（σ（max））（r（2）分别为0.44和0.41）和微结构参数（0.50 < r（2）< 0.56，P < 0.001），与DMB的相关性仍然存在（P <0.003）。骨折前功（W）的变化与骨折前功（W）的变化趋势一致（0.23 < r（2）< 0.46，P < 0.045）。我们的结论是松质骨组织矿化越多，其刚度和抗压强度越高。这可以解释当DMB在生理范围内被修改而不需要改变BMV和骨微结构时骨强度的增加。这些修改对骨折风险的影响和这些数据的治疗意义仍有待分析。(C)2003年爱思唯尔公司All rights reserved.
Strength of bones depends on bone matrix volume (BMV), bone microarchitecture, and also on the degree of mineralization of bone (DMB). We have recently shown in osteoporotic patients treated with alendronate that fracture risk decreased and bone mineral density increased with a parallel increase of the DMB due to prolonged secondary mineralization but without modifications of BMV or bone microarchitecture. DMB and strength were both measured at the tissue level in calcaneus bone samples taken at autopsy from 20 subjects (aged 78 +/- 8 years, 8 women, 12 men) who died suddenly without apparent bone disease. DMB parameters measured on microradiographs (mean DMB, distribution of DMB, most frequent maximum DMB value, and width at half maximum, an index reflecting the homogeneity of DMB) were compared with those reported in iliac cancellous bone samples of 43 human bones. Histomorphometric measurements of microarchitectural parameters (TbTh, TbN, and TbSp) were also measured. Compression tests were performed on contiguous samples of the same calcaneus on a universal screw-driven machine (Schenck RSA 250). A 5000-N load cell (TME, F 501 TC) measured the compressive load. The displacement was measured directly on the sample using a specific displacement transducer developed by the The apparent Young's modulus (E), the maximal strength (sigmamax), and the work (W) until failure were measured. In human cancellous bone tissue, mean DMB (+/-SD) was higher in calcaneus (1.135 +/- 0.147 g/cm(3)) than in iliac crest (1.098 +/- 0.077 g/cm(3)). The mean most frequent maximum DMB values (mean DMB freq. max.) were 1.118 +/- 0.175 g/cm(3) in calcaneus and 1.108 +/- 0.095 g/cm(3) in iliac samples, and DMB was more heterogeneous in calcaneus than in iliac samples (mean width at half maximum were 0.270 +/- 0.127 versus 0.227 +/- 0.056 g/cm(3), respectively). Compression tests revealed significant positive linear correlations between DMB and both elastic modulus (r(2) = 0.69) and maximal strength (r(2) = 0.69). Correlations with DMB persisted (P < 0.003) even after adjustment for both calcified bone volume, for the Young's modulus (E), the maximal strength (sigma(max)) (r(2) = 0.44 and 0.41, respectively), and microarchitectural parameters (0.50 < r(2) < 0.56, P < 0.001). The same results were obtained with the work to fracture (W) (0.23 < r(2) < 0.46, P < 0.045). We conclude that the more the cancellous tissue was mineralized, the higher was its stiffness and compressive strength. This may explain the increase in bone strength when DMB is modified in a physiological range without necessary changes of BMV and bone microarchitecture. The impact of such modifications on fracture risk and the therapeutic implications of these data remain to be analyzed. (C) 2003 Elsevier Inc. All rights reserved.