Department of Biomedical Sciences, Texas A&M University College of Dentistry, Dallas, Texas, USA.
Tissue Eng Part B Rev. 2022 Apr;28(2):261-278. doi: 10.1089/ten.TEB.2020.0322. Epub 2021 Mar 8.
Bone is composed of dense and solid cortical bone and honeycomb-like trabecular bone. Although cortical bone provides the majority of mechanical strength for a bone, there are few studies focusing on cortical bone repair or regeneration. Osteons (the Haversian system) form structural and functional units of cortical bone. In recent years, emerging evidences have shown that the osteon structure (including osteocytes, lamellae, lacunocanalicular network, and Haversian canals) plays critical roles in bone mechanics and turnover. Therefore, reconstruction of the osteon structure is crucial for cortical bone regeneration. This article provides a systematic summary of recent advances in osteons, including the structure, function, turnover, and regenerative strategies. First, the hierarchical structure of osteons is illustrated and the critical functions of osteons in bone dynamics are introduced. Next, the modeling and remodeling processes of osteons at a cellular level and the turnover of osteons in response to mechanical loading and aging are emphasized. Furthermore, several bioengineering approaches that were recently developed to recapitulate the osteon structure are highlighted. Impact statement This review provides a comprehensive summary of recent advances in osteons, especially the roles in bone formation, remodeling, and regeneration. Besides introducing the hierarchical structure and critical functions of osteons, we elucidate the modeling and remodeling of osteons at a cellular level. Specifically, we highlight the bioengineering approaches that were recently developed to mimic the hierarchical structure of osteons. We expect that this review will provide informative insights and attract increasing attentions in orthopedic community, shedding light on cortical bone regeneration in the future.
骨由致密而坚实的皮质骨和蜂窝状的小梁骨组成。虽然皮质骨为骨骼提供了大部分的机械强度，但很少有研究关注皮质骨的修复或再生。骨单位（哈弗斯系统）构成了皮质骨的结构和功能单位。近年来，新出现的证据表明，骨单位结构（包括骨细胞、板层、骨陷窝和骨小管网络以及哈弗斯管）在骨骼力学和转换中起着关键作用。因此，重建骨单位结构对于皮质骨再生至关重要。本文系统总结了骨单位的最新研究进展，包括骨单位的结构、功能、转换和再生策略。首先，本文阐述了骨单位的层次结构，并介绍了骨单位在骨骼动力学中的关键作用。接下来，强调了骨单位在细胞水平上的建模和重塑过程以及骨单位对机械加载和衰老的反应性转换。此外，还重点介绍了最近开发的几种用于再现骨单位结构的生物工程方法。影响评估 本综述全面总结了骨单位的最新研究进展，特别是骨单位在骨形成、重塑和再生中的作用。除了介绍骨单位的层次结构和关键功能外，我们还阐明了骨单位在细胞水平上的建模和重塑。具体而言，我们强调了最近开发的几种用于模拟骨单位层次结构的生物工程方法。我们希望本综述将提供有价值的见解，并在骨科领域引起越来越多的关注，为未来的皮质骨再生提供新的思路。
