Demonstration of multipotent stem cells in the adult human endometrium by in vitro chondrogenesis.

Stem cells are defined by their unique capacity for self-renewal and multilineage differentiation. Stem cells have been obtained from multiple extramedullary tissues. Recently, a population of progenitor cells have been identified in the endometrium. However, multilineage differentiation of endometrial stem cells has not been reported. Endometrial tissue was obtained from reproductive-aged women undergoing surgery for benign disease, from which monolayer endometrial stromal cell (ESC), myometrial, fibroid, fallopian tube, and uterosacral ligament tissue cultures were generated. Once confluent, cells were trypsinized and centrifuged in conical tubes to form a cell pellet. Cell pellets were cultured in a defined chondrogenic media (CM) containing dexamethasone and transforming growth factor (TGF)-beta2 or TGF-beta 3 for 3 to 21 days. Samples were analyzed for markers of human articular cartilage, including sulfated glycosaminoglycans and expression of type II collagen. ESC pellets cultured in CM were found to contain cells that resemble chondrocytes. These cells expressed sulfated glycosaminoglycans and type II collagen typical of human articular cartilage. Myometrial, fibroid, fallopian tube, and uterosacral ligament cells were unable to undergo chondrogenic differentiation using the pellet culture method. Cells derived from the endometrium were able to differentiate into a heterologous cell type: chondrocytes, thus demonstrating the presence of multipotent stem cells. Endometrium is a potential source of multipotent stem cells.