Stem Cells in Endometriosis

A growing body of evidence indicates that adult stem/progenitor cells reside in the human endometrium, and it is likely they are responsible for its remarkable capacity to regenerate the functional layer following menstruation. Rare cells with epithelial progenitor or mesenchymal stem activity have recently been discovered, and the mesenchymal stem cell-like cells can be isolated from human endometrium as CD146+PDGFR+ cells. Endometrial epithelial progenitors are postulated to reside in the bases of glands in the basalis layer, while the mesenchymal stem cell-like cells are found in both basalis and functionalis in a perivascular location. Endometrial stem/progenitor cells may be derived from residual fetal stem cells, although emerging evidence suggests that the bone marrow may also contribute to the pool of adult stem cells. The presence of mesenchymal stem cells in menstrual blood indicates that endometrial stem/progenitor cells may be retrogradely shed during menstruation via the fallopian tubes into the peritoneal cavity and give rise to endometriotic lesions.