Blood Vessels as a Source of Progenitor Cells in Human Embryonic and Adult Life

Recent experimental results in culture and in vivo are summarized that show the existence of developmental relationships between cells that build up blood vessel walls and some previously unrelated tissues and organs. It was formerly demonstrated, in lower vertebrates as well as mammals, including humans, that discrete subsets of blood-forming endothelial cells play a key role in the emergence of the definitive hematopoietic system. We have also documented the existence in human skeletal muscle of endothelium-borne, extremely potent myogenic progenitor cells. Finally, we have characterized and purified perivascular cells-or pericytes-from human tissues and demonstrated their ability to give rise to mesodermal differentiated derivatives, principally skeletal muscle.