Stem cells in the blood vessel wall can regulate bone repair
While stopping short of re-growing entire limbs like some animals, our bodies have a great capacity to recover from injury, including fixing broken bones. Guiding these repairs around the body are perivascular stem cells (PSCs), located in the lining of blood vessels. Rather than make bone tissue themselves, PSCs act as organisers, encouraging other stem cells to produce bone. To communicate this message, PSCs secrete extracellular vesicles, tiny membrane spheres which deliver packages of proteins and RNA to immature bone cells. Contact with these vesicles in the laboratory causes recipient cells to multiply, move and become bone cells, as expected after a real breakage. In mice with defects in bones in their skull, injections with PSC-derived extracellular vesicles boost numbers of immature bone cells in the injured area (pictured, in green, lower panel) and accelerate healing compared to no treatment (top), suggesting potential as a therapeutic tool to enhance recovery.
Written by Emmanuelle Briolat
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