Department of Biologic and Materials Sciences, School of Dentistry, University of Michigan, MI, USA.
Department of Biomedical Engineering, College of Engineering, University of Michigan, MI, USA.
Acta Biomater. 2024 Oct 1;187:409-421. doi: 10.1016/j.actbio.2024.08.042. Epub 2024 Aug 28.
Currently, principles of tissue engineering and implantology are uniformly applied to all bone sites, disregarding inherent differences in collagen, mineral composition, and healing rates between craniofacial and long bones. These differences could potentially influence bone quality during the healing process. Evaluating bone quality during healing is crucial for understanding local mechanical properties in regeneration and implant osseointegration. However, site-specific changes in bone quality during healing remain poorly understood. In this study, we assessed newly formed bone quality in sub-critical defects in the maxilla and femur, while impairing collagen cross-linking using β-aminopropionitrile (BAPN). Our findings revealed that femoral healing bone exhibited a 73 % increase in bone volume but showed significantly greater viscoelastic and collagen changes compared to surrounding bone, leading to increased deformation during long-term loading and poorer bone quality in early healing. In contrast, the healing maxilla maintained equivalent hardness and viscoelastic constants compared to surrounding bone, with minimal new bone formation and consistent bone quality. However, BAPN-impaired collagen cross-linking induced viscoelastic changes in the healing maxilla, with no further changes observed in the femur. These results challenge the conventional belief that increased bone volume correlates with enhanced tissue-level bone quality, providing crucial insights for tissue engineering and site-specific implant strategies. The observed differences in bone quality between sites underscore the need for a nuanced approach in assessing the success of regeneration and implant designs and emphasize the importance of exploring site-specific tissue engineering interventions. STATEMENT OF SIGNIFICANCE: Accurate measurement of bone quality is crucial for tissue engineering and implant therapies. Bone quality varies between craniofacial and long bones, yet it's often overlooked in the healing process. Our study is the first to comprehensively analyze bone quality during healing in both the maxilla and femur. Surprisingly, despite significant volume increase, femur healing bone had poorer quality compared to the surrounding bone. Conversely, maxilla healing bone maintained consistent quality despite minimal bone formation. Impaired collagen diminished maxillary healing bone quality, but had no further effect on femur bone quality. These findings challenge the notion that more bone volume equals better quality, offering insights for improving tissue engineering and implant strategies for different bone sites.
目前，组织工程学和植入物学的原则被统一应用于所有骨部位，而忽略了颅面骨和长骨之间胶原、矿物质组成和愈合速度的固有差异。这些差异可能会影响愈合过程中的骨质量。评估愈合过程中的骨质量对于理解再生和植入物骨整合中的局部机械性能至关重要。然而，愈合过程中骨质量的特定部位变化仍知之甚少。在这项研究中，我们使用β-氨基丙腈（BAPN）抑制胶原交联，评估了上颌骨和股骨亚临界缺损中新形成骨的质量。我们的研究结果表明，股骨愈合骨的骨体积增加了 73%，但与周围骨相比，表现出更大的粘弹性和胶原变化，导致长期加载时变形增加，早期愈合时骨质量较差。相比之下，愈合的上颌骨与周围骨相比保持了相当的硬度和粘弹性常数，新骨形成较少，骨质量一致。然而，BAPN 抑制胶原交联会引起愈合上颌骨的粘弹性变化，但股骨无进一步变化。这些结果挑战了骨体积增加与增强组织水平骨质量相关的传统观念，为组织工程学和特定部位植入策略提供了重要的见解。不同部位之间骨质量的差异突显了在评估再生和植入物设计的成功时需要采取细致入微的方法，并强调了探索特定部位组织工程干预的重要性。
