Mediators of mechanotransduction between bone cells

Abstract

Mechanical forces are known to regulate the function of tissues in the body, including bone. Bone adapts to its mechanical environment by altering its shape and increasing its size in response to increases in mechanical load associated with exercise, and by decreasing its size in response to decreases in mechanical load associated with microgravity or prolonged bed rest. Changes in bone size and shape are produced by a cooperative action of two main types of the bone cells - osteoclasts that destroy bone and osteoblasts that build bone. These cell types come from different developmental origins, and vary greatly in their characteristics, such as size, shape, and expression of receptor subtypes, which potentially may affect their responses to mechanical stimuli. The objective of this study is to compare the responses of osteoclasts and osteoblasts to mechanical stimulation.

This study has allowed us to conclude the following:
1. A mediator is released from a single source cell.
2. The response to the mediator changes with distance.
3. The value of the apparent diffusion coeficient increases with distance.
4. A plausible proposed mechanism is that ATP is released and degrades to ADP.
5. Future experiments are required to confim that ATP is the mediator as suggested.