Proposal for the regulatory mechanism of Wolff's law

Abstract

Summary:It is currently believed that the trabecular structure in bone is the result of a dynamic remodeling process controlled bÿ mechanical loads. We propose a regulatory mechanism based on the hypothesis that osteocytes located within the bone sense mechanical signals and that these cells mediate osteoclasts and osteoblasts in their vicinity to adapt bone mass. A computer-simulation model based on these assumptions was used to investigate if the adaptation of bone, in the sense of Wolffs law, and remodeling phenomena, as observed in reality, can be explained by such a local control process. The model produced structures resem bling actual trabecular architectures. The architecture transformed after the external loads were changed, aligning the trabeculae with the actual principal stress orientation, in accordance with Wolffs trajectorial hypothesis. As in reality, the relative apparent density of the structure depended on the magnitude of the applied stresses. Osteocyte density influenced the remodeling rate, which also is consistent with experimental findings. Furthermore, the results indicated that the domain of influence of the osteocytes affects the refine ment of the structure as represented by separation and thickness of the struts. We concluded that the trabec ular adaptation to mechanical load, as described by Wolff, can be explained by a relatively simple regulatory model. The model is useful for investigating the effects of physiological parameters on the development, maintenance, and adaptation of bone.

Determination of hip-joint loading patterns of living and extinct mammals using an inverse Wolff’s law approach

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Mechanisms of osteocyte stimulation in osteoporosis

“…Bone lining cells, osteoblasts and osteocytes, have been proposed to act as mechanosensors within bone tissue (Cowin et al 1991;Lanyon 1993;Mullender and Huiskes 1997). Osteocytes are the most widely accepted candidates for sensing mechanical stresses in bone (Ajubi et al 1996;Burger and Veldhuijzen 1993a;Carter and Caler 1985;Cowin et al 1991;Huiskes et al 2000;KleinNulend et al 1995;Lanyon 1993;Mullender and Huiskes 1995;Mullender and Huiskes 1997;Mullender et al 1994;Smit and Burger 2000;Weinbaum et al 1994;Westbroek et al 2000).…”