Osteocyte pericellular and perilacunar matrices as markers of bone-implant mechanical integrity

To develop durable bone healing strategies through improved control of bone repair,it is of critical importance to understand the mechanisms of bone mechanical integrity when in contact with biomaterials and implants.Bone mechanical integrity is defined here as the adaptation of structural properties of remodeled bone in regard to an applied mechanical loading.Accordingly,the authors present why future investigations in bone repair and regeneration should emphasize on the matrix surrounding the osteocytes.Osteocytes are mechanosensitive cells considered as the orchestrators of bone remodeling,which is the biological process involved in bone homeostasis.These bone cells are trapped in an interconnected porous network,the lacunocanalicular network,which is embedded in a bone mineralized extracellular matrix.As a consequence of an applied mechanical loading,the bone deformation results in the deformation of this lacunocanalicular network inducing a shift in interstitial fluid pressure and velocity,thus resulting in osteocyte stimulation.The material environment surrounding each osteocyte,the so called perilacunar and pericellular matrices properties,define its mechanosensitivity.While this mechanical stimulation pathway is well known,the laws used to predict bone remodeling are based on strains developing at a tissue scale,suggesting that these strains are related to the shift in fluid pressure and velocity at the lacunocanalicular scale.While this relationship has been validated through observation in healthy bone,the fluid behavior at the bone-implant interface is more complex.The presence of the implant modifies fluid behavior,so that for the same strain at a tissue scale,the shift in fluid pressure and velocity will be different than in a healthy bone tissue.In that context,new markers for bone mechanical integrity,considering fluid behavior,have to be defined.The viewpoint exposed by the authors indicates that the properties of the pericellular and the perilacunar matrices have to be systematically investigated and used as structural markers of fluid behavior in the course of bone biomaterial development.

Nanostructure and mechanical properties of the osteocyte lacunar-canalicular network-associated bone matrix revealed by quantitative nanomechanical mapping

Osteocytes 是在他们形成称为 lacunar-canalicular 网络(LCN ) 的一个大表面区域网络的骨头矩阵嵌入的主要骨头房间，互连他们有由 canaliculi 的过失的居民空格。增加的证据向在维持骨头质量起一个枢轴的作用的 osteocytes 指。在一方面， osteocytes 通过 LCN 播送机械紧张和 microenvironmental 信号调整造骨细胞和骨破折的活动；在另一方面， osteocytes 被建议能改变联系 LCN 的骨头矩阵。由于涉及对联系 LCN 的骨头矩阵的评价和描述的挑战，然而，很少对它的结构和相应机械性质被知道。在这个工作，我们使用了量的 nanomechanical 印射， backscattered 电子成像，和 nanoindentation 描绘联系 LCN 的骨头矩阵。结果证明这些技术能被用来探查联系 LCN 的骨头矩阵。Nanoindentation 并且量的机械印射揭示与 osteocyte 过失和 canaliculi 联系的骨头矩阵的空间地不同类的机械性质。获得的 nano 地形学和相应 nano 机械的地图在 osteocyte 过失和 canaliculi 的立即的附近揭示改变的机械性质，它不能完全被地志的变化解释。