Page 31 - Physico-Chemical Niche Conditions for Bone Cells

Chapter 2
Figure 1. Schematic showing how mechanical stimulation affects osteocytes and myoblasts within their native niche. Bone and muscle mass are regulated by many factors that include growth factors, hormones, nutrition, genetics and, in particular, mechanical stimulation, e.g. tensile stress and shear stress upper panel shows the early and late-osteocytes in their lacuna making contact with each other via their lamipodia extending through the canaliculi making contact with each other and with osteoblasts at the endosteum, Note that the late-osteocyte is embedded within its calcified matrix while the matrix of the early osteocyte matrix is in a premature state of calcification. Due to the differences in calcification and stiffness, early osteocytes are likely subjected to pressure as well as tensile and shear deformations, while late-osteocytes are subjected to fluid shear stress causing mechanical loading of transmembrane complexes and glycocalyx and presumably small local deformations within the plasmamembrance at the cell body and lamipodia. MuSCs are enclosed between the sarcolemma of the host myofiber and the basal lamina and have transmembrane complexes via which the MuSC is connected to these structures. Upon shortening of the myofibers, MuSCs will be subjected to pressure and when myofibers fibers are stretched these cells will be strained and subjected to shear forces.
short-lived FAPs [30]. Stimulated FAPs also affect the MuSCs as they communicate with these cells via producing paracrine factors [30]. In addition, MuSCs are associated to neuromuscular junction (NMJ) degeneration and regeneration in response to denervation [31]. Possibly
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