Architecture of the osteocyte network correlates with bone material quality

Abstract

In biological tissues such as bone, cell function and activity crucially depend on the physical properties of the extracellular matrix which the cells synthesize and condition. During bone formation and remodeling, osteoblasts get embedded into the matrix they deposit and differentiate to osteocytes. These cells form a dense network throughout the entire bone material. Osteocytes are known to orchestrate bone remodeling. However, the precise role of osteocytes during mineral homeostasis and their potential influence on bone material quality remains unclear. To understand the mutual influence of osteocytes and extracellular matrix, it is crucial to reveal their network organization in relation to the properties of their surrounding material. Here we visualize and topologically quantify the osteocyte network in mineralized bone sections with confocal laser scanning microscopy. At the same region of the sample, synchrotron smallangle X-ray scattering is used to determine nanoscopic bone mineral particle size and arrangement relative to the cell network. Major findings are that most of the mineral particles reside within less than a micrometer from the nearest cell network channel and that mineral particle characteristics depend on the distance from the cell network. The architecture of the network reveals optimization with respect to transport costs between cells and to blood vessels. In conclusion, these findings quantitatively show that the osteocyte network provides access to a huge mineral reservoir in bone due to its dense organization. The observed correlation between the architecture of osteocyte networks and bone material properties supports the hypothesis that osteocytes interact with their mineralized vicinity and thus, participate in bone mineral homeostasis.

Airbrushed Composite Polymer Zr-ACP Nanofiber Scaffolds with Improved Cell Penetration for Bone Tissue Regeneration

“…17 It is also known that cells in osteocyte networks within lacunar and canalicular cavities are highly aligned and feature extensive cell-cell interconnectivity on a microscale. 18 In another study, ECM fiber alignment was shown to impact cell length order at lengths greater than a few hundred microns; in addition, it also indicated that the extent of cell order can correspond to bone type and quality. 19 These studies underscore the importance of the material morphology on cell arrangement and interconnectivity within native and 3D scaffolds.…”

Structural properties of the mastoid using image analysis and visualization

“…7.13(left). Compared to the skeleton scheme from [42,49], the medial axis from this study does not seems to fully represent the topology at the first impression, as shown in Fig. 7.13 when comparing both schemes.…”

“…Moreover, near the ossicular chain at the superior part of the bone in Fig. 7.13, the skeleton from [42,49] form blobs frequently observed along the complete mastoid air cell system skeletonization, as highlighted in Fig. 7.7.…”

“…7.13 when comparing both schemes. However, the medial axis implemented in this study has several advantages over the scheme from [42,49]. Many air cells in Fig.…”

“…7.13(left), where the medial axis from the current study does not show any spur branches. The time to process the medial axis using this analysis was considered faster compared to the scheme from [42,49].…”