Institute for Osteology and Biomechanics, University Medical Center Hamburg-Eppendorf, Lottestrasse 55a, 22529, Hamburg, Germany.
Laboratory for Anthropology, Institute of Anatomy, Faculty of Medicine, University of Belgrade, Dr Subotica 4/2, 11000, Belgrade, Serbia.
Small. 2017 Jan;13(3). doi: 10.1002/smll.201602215. Epub 2016 Nov 7.
Osteocytes-the central regulators of bone remodeling-are enclosed in a network of microcavities (lacunae) and nanocanals (canaliculi) pervading the mineralized bone. In a hitherto obscure process related to aging and disease, local plugs in the lacuno-canalicular network disrupt cellular communication and impede bone homeostasis. By utilizing a suite of high-resolution imaging and physics-based techniques, it is shown here that the local plugs develop by accumulation and fusion of calcified nanospherites in lacunae and canaliculi (micropetrosis). Two distinctive nanospherites phenotypes are found to originate from different osteocytic elements. A substantial deviation in the spherites' composition in comparison to mineralized bone further suggests a mineralization process unlike regular bone mineralization. Clearly, mineralization of osteocyte lacunae qualifies as a strong marker for degrading bone material quality in skeletal aging. The understanding of micropetrosis may guide future therapeutics toward preserving osteocyte viability to maintain mechanical competence and fracture resistance of bone in elderly individuals.
成骨细胞——骨骼重塑的核心调控者——被包裹在一个由微腔（骨陷窝）和纳米通道（骨小管）组成的网络中，这些微腔和纳米通道贯穿于矿化的骨骼中。在一个与衰老和疾病相关的迄今仍不为人知的过程中，骨陷窝-骨小管网络中的局部堵塞会破坏细胞通讯并阻碍骨骼的动态平衡。通过利用一系列高分辨率成像和基于物理的技术，本文表明，局部堵塞是通过在骨陷窝和骨小管（微孔血栓）中钙化纳米球的积累和融合而形成的。研究发现，两种不同的纳米球表型来源于不同的成骨细胞。与矿化骨骼相比，纳米球的成分有明显的偏差，这进一步表明其矿化过程不同于常规的骨骼矿化。显然，成骨细胞骨陷窝的矿化可作为骨骼老化过程中降解骨材料质量的一个强有力的标志物。对微孔血栓的理解可能为未来的治疗方法提供指导，以保持成骨细胞的活力，从而维持老年人骨骼的机械性能和抗骨折能力。
