Perivascular Progenitor Cells for Bone Regeneration

Perivascular progenitor cells are of growing interest in the field of bone tissue engineering. Perivascular progenitor cells have mesenchymal stem/stromal cell (MSC) characteristics, including multipotentiality, self-renewal, immunomodulatory functions, and diverse roles in tissue repair. From human tissue, the purification of perivascular progenitor cells is most common from subcutaneous white adipose tissue, although all vascularized organs studied to date have a perivascular progenitor cell population. Microvascular pericytes are commonly isolated as a CD146+CD34−CD31−CD45− cell population, while adventitial progenitor cells are more commonly identified as a CD146−CD34+CD31−CD45− population. Perivascular progenitor cells have been applied in diverse orthopedic conditions, including both ectopic and orthotopic models of bone formation/regeneration. This review covers studies to date in bone tissue engineering as well as several emerging areas of study, including the concept of regional specification within the perivascular niche.