Researchers identify mechanism by which exercise strengthens bones and immunity
DALLAS (24 Feb 2021) >> Scientists have identified the specialized environment ('niche') in the bone marrow where new bone and immune cells are produced. The study also shows that movement-induced stimulation is required for the maintenance of this niche, as well as the bone and immune-forming cells that it contains.
... forces created from walking or running are transmitted from bone surfaces along arteriolar blood vessels into the marrow inside bones. Bone-forming cells that line the outside of the arterioles sense these forces and are induced to proliferate. This not only allows the formation of new bone cells, which helps to thicken bones, but the bone-forming cells also secrete a growth factor that increases the frequency of cells that form lymphocytes around the arterioles. Lymphocytes are the B and T cells that allow the immune system to fight infections.
In bone-forming cells with mechanical force senses deactivated, the formation of new bone cells and lymphocytes was reduced, causing bones to become thinner and reducing the ability to clear a bacterial infection.
“We think we’ve found an important mechanism by which exercise promotes immunity and strengthens bones, on top of other mechanisms previously identified by others”.