Toward the use of endometrial and menstrual blood mesenchymal stem cells for cell-based therapies.

INTRODUCTION: Bone marrow is a widely used source of mesenchymal stem cells (MSCs) for cell-based therapies. Recently, endometrium - the highly regenerative lining of the uterus - and menstrual blood have been identified as more accessible sources of MSCs. These uterine MSCs include two related cell types: endometrial MSCs (eMSCs) and endometrial regenerative cells (ERCs). AREAS COVERED: The properties of eMSCs and ERCs and their application in preclinical in vitro and in vivo studies for pelvic organ prolapse, heart disorders and ischemic conditions are reviewed. Details of the first clinical Phase I and Phase II studies will be provided. EXPERT OPINION: The authors report that eMSCs and ERCs are a readily available source of adult stem cells. Both eMSCs and ERCs fulfill the key MSC criteria and have been successfully used in preclinical models to treat various diseases. Data on clinical trials are sparse. More research is needed to determine the mechanism of action of eMSCs and ERCs in these regenerative medicine models and to determine the long-term benefits and any adverse effects after their administration.