Seminar über aktuelle Fragen zur Dynamik komplexer Fluide: Relationship between the fluid flow pattern through the lacunocanalicular network and the adaptive mechano-response in bone
Jan 24, 2020
10:15 - 11:15
Alexander van Tol
- Max Planck Institute of Colloids and Interfaces, Potsdam
Max-Planck-Institut für Dynamik und Selbstorganisation (MPIDS)
Osteocytes play an important role in bone mechano-sensation, a process crucial for bone maintenance and adaptation to changing mechanical demands. Their cell bodies and processes reside in a network of cavities and sub-micrometer wide canals called lacunae and canaliculi, respectively. According to the widely supported fluid flow hypothesis mechanical load induces interstitial flow through the lacunocanalicular network (LCN), resulting in shear force on the osteocytes. The mechano-response of bone is site-dependent1. The aim of our study was to analyze and model the fluid flow through the LCN to assess the relationship between LCN topology and local differences in mechano-response in human femur and mouse tibiae.
For our studies we used the femur of a 56 year old woman without any known diseases and mouse tibiae that were loaded in vivo to elicit a bone formation/resorption response. Time-lapse in vivo microCT was used in the mouse study to quantify the mechano-response in the tibiae. The porosity in the bones was stained with rhodamine and the LCN was imaged using 3D confocal scanning laser microscopy. Circuit theory was used to model fluid flow through each canaliculus of the LCN (fig. 1). Both human and mouse bone show a strong heterogeneity in LCN architecture. Our analysis shows that both the LCN topology and vascular porosity have a major influence on interstitial fluid flow patterns, which correlate with local bone formation/resorption data (P < 0.001, R2 = 0.6). In conclusion, our results show that the LCN network topology could either attenuate or amplify interstitial fluid flow, and by doing so considerably influence the local mechano-response in bone.