Biomedical Engineering Reference
In-Depth Information
Fig. 1 Simplified chain of the mechano-transduction of bone remodelling (reproduced with
permission from [ 75 ])
In particular, the understanding of the transduction of physical signal is still in
debate [ 19 ]. The current trend consists in considering that the central role in the
mechano-reception is played by the osteocytes [ 18 , 64 , 66 , 159 ].
These are bone cells embedded in the bone matrix volume. Their bodies are
located in ellipsoidal cavities of 10-30 lm called the lacunae. These lacunae are
connected thanks to canaliculi whose diameters are on the order of magnitude if
0 : 1 lm : Cytoplasmic osteocyte cell processes that develop from the cell body
occupy the central zone of the canaliculi so that the interstitial fluid pathway
roughly corresponds to an annular geometry. Thus, the stellar osteocytes form a
network in the bone volume and communicate one to the other through the gap
junctions. This particular configuration of the couple osteocytes/lacuno-canalicular
porosity (OCY/PLC) explains that it is often considered as the mechano-sensitive
organ of bone.
In summary, if it is commonly accepted that the effector cells are the osteoclasts
and osteoblasts and the mechano-sensitive cells are the osteocytes [ 92 ], the
understanding of the nature of the triggering signals for the different cellular
activities is much debated. The following section proposes a brief review of the
classical hypotheses related to the mechanism by which bone cells sense their
mechanical environment and initiate the deposition or resorption of bone tissue.
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