Assessment of the human bone lacuno-canalicular network at the nanoscale and impact of spatial resolution

Abstract

cécile olivier 1,2 , peter cloetens 2 & françoise peyrin 1,2* Recently, increasing attention has been given to the study of osteocytes, the cells that are thought to play an important role in bone remodeling and in the mechanisms of bone fragility. the interconnected osteocyte system is deeply embedded inside the mineralized bone matrix and lies within a closely fitted porosity known as the lacuno-canalicular network. However, quantitative data on human samples remain scarce, mostly measured in 2D, and there are gaps to be filled in terms of spatial resolution. In this work, we present data on femoral samples from female donors imaged with isotropic 3D spatial resolution by magnified X-ray phase nano computerized-tomography. We report quantitative results on the 3D structure of canaliculi in human femoral bone imaged with a voxel size of 30 nm. We found that the lacuno-canalicular porosity occupies on average 1.45% of the total tissue volume, the ratio of the canalicular versus lacunar porosity is about 37.7%, and the primary number of canaliculi stemming from each lacuna is 79 on average. The examination of this number at different distances from the surface of the lacunae demonstrates branching in the canaliculi network. We analyzed the impact of spatial resolution on quantification by comparing parameters extracted from the same samples imaged with 120 nm and 30 nm voxel sizes. To avoid any bias related to the analysis region, the volumes at 120 nm and 30 nm were registered and cropped to the same field of view. Our results show that the measurements at 120 and 30 nm are strongly correlated in our data set but that the highest spatial resolution provides more accurate information on the canaliculi network and its branching properties.

Mechanisms of Antibiotic Failure During Staphylococcus aureus Osteomyelitis

“…Osteocytes, the major cell type embedded within the bone matrix (77), create a threedimensional network in which osteocytes directly connect individual lacunae via canaliculi (78). Lacunae are the spaces containing the individual osteocytes, whereas the canaliculi are the channels containing the osteocyte cytoplasmic processes (79). Recently, S. aureus was found to invade the OLCN in a murine model of osteomyelitis (80).…”

Closing the osteon: Do osteocytes sense strain rate rather than fluid flow?

“…[ 53 ] A more recent study estimates this to be as low as 1.45%. [ 103 ] While this difference presents a large quantitative discrepancy, the qualitative effects on stable fluid flow and declining shear strain rate are rather limited, because also matrix permeability was calculated assuming 5% porosity; [ 52 ] assuming a lower porosity would result in higher permeability and essentially the same fluid flow. In other words: lacuno‐canalicular porosity is not an independent magnitude in the FE model.…”

Maxillary Sinus in Dental Implantology

“…The general existence and micro-anatomy of the LCN have been known for a long time. The connections of the osteocyte network with other regions of the body [16] and its importance for phosphate metabolism [13,15] were debated in recent research [17,18]. As endocrine cells, osteocytes have an impact on many organs [16].…”