Pressure and shear stress in trabecular bone marrow during whole bone loading

JOURNAL OF BIOMECHANICS

卷:48

Article

Metzger, Thomas A.¹  Schwaner, Stephen A.²  LaNeve, Anthony J.²  Kreipke, Tyler C.¹  Niebur, Glen L.¹ 

[1] Univ Notre Dame, Bioengn Grad Program, Tissue Mech Lab, Notre Dame, IN 46556 USA

[2] Univ Notre Dame, Dept Aerosp & Mech Engn, Notre Dame, IN 46556 USA

关键词: Bone marrow;    Trabecular bone;    Whole bone loading;    Experimental measurements;    Computational modeling;   

DOI  :  10.1016/j.jbiomech.2015.07.028

来源: Elsevier

【 摘 要 】

Skeletal adaptation to mechanical loading is controlled by mechanobiological signaling. Osteocytes are highly responsive to applied strains, and are the key mechanosensory cells in bone. However, many cells residing in the marrow also respond to mechanical cues such as hydrostatic pressure and shear stress, and hence could play a role in skeletal adaptation. Trabecular bone encapsulates marrow, forming a poroelastic solid. According to the mechanical theory, deformation of the pores induces motion in the fluid-like marrow, resulting in pressure and velocity gradients. The latter results in shear stress acting between the components of the marrow. To characterize the mechanical environment of trabecular bone marrow in situ, pore pressure within the trabecular compartment of whole porcine femurs was measured with miniature pressure transducers during stress-relaxation and cyclic loading. Pressure gradients ranging from 0.013 to 0.46 kPa/mm were measured during loading. This range was consistent with calculated pressure gradients from continuum scale poroelastic models with the same permeability. Micro-scale computational fluid dynamics models created from computed tomography images were used to calculate the micromechanical stress in the marrow using the measured pressure differentials as boundary conditions. The volume averaged shear stress in the marrow ranged from 1.67 to 24.55 Pa during cyclic loading, which exceeds the mechanostimulatory threshold for mesenchymal lineage cells. Thus, the loading of bone through activities of daily living may be an essential component of bone marrow health and mechanobiology. Additional studies of cell-level interactions during loading in healthy and disease conditions will provide further incite into marrow mechanobiology. (C) 2015 Elsevier Ltd. All rights reserved.

【 授权许可】

Free