A team of researchers led by Dr. Xiaolong Meng at the Bio-Communications Research Institute in Wichita have identified a potentially rich source of stem cells – the uterine endometrial lining. Meng and colleagues demonstrated that these ‘Endometrial Regenerative Cells’ (ERC) can be grown into at least 9 different types of cell lines, including cardiac, hepatic, pleural, respiratory epithelial, adipocytic, osteogenic, pancreatic, and neurocytic cells.
The Endometrial Regenerative Cells which can be isolated from the menstrual blood of a healthy woman, doubled every 19.4 hours, which was faster than the replication rate of the control umbilical cord blood and bone marrow stem cells used in the study. These cells could be cultured for more than 68 doublings without any karyotypic or functional abnormalities. In addition to the high replication rate, the ERC produced growth factors such as Granulocyte-Macrophage Colony-Stimulating Factor (GM-CSF), angiopoietin-2, and Platelet-Derived Growth Factor (PDGF-BB) at a rate of about 10-100,000 times more than the control mesenchymal cell lines derived from umbilical cord blood.
In a study conducted by Wolff et al at the Yale University School of Medicine (Reproductive Sciences; September, 2007), the endometrial stromal cell pellets derived from women of reproductive age cultured on a chondrogenic defined media were found to develop into chondrocytes, indicating the presence of multipotent stem cells in the endometrial tissue.
In another study done to compare the proliferative potential of endometrial stem/ progenitor cells, Gargett et al (Human Reproduction, 2005) purified the epithelial and stromal cells and cultured them separately in limiting dilutions. They concluded that the rare epithelial and stromal high proliferative potential-colony forming units (HPP-CFU) have self-renewal capacity and a high proliferative potential. They also found that the stromal HPP-CFU differentiated into 4 cell lineages- adipocytes, smooth muscles, osteocytes, and chondrocytes when cultured in appropriate differentiating media.
Stem cells are undifferentiated cells with the unique capability of dividing mitotically and the potential to differentiate into any specialized cell like the muscle cells, hepatic cells, or blood cells when required. The current sources of stem cells include embryonic stem cells, and adult stem cells from umbilical cord blood and the bone marrow.
The use of embryonic or adult stem cells is fraught with controversies and disadvantages. Limitations of adult stem cells include the inadequate harvest of cells and multipotency, giving rise to only certain cell lines, unlike the pluripotent embryonic stem cells which can be obtained in large quantities and can differentiate into any specialized cell lines. However embryonic stem cells are associated with serious ethical concerns and host rejections.
With the new study, which was funded by Medistem Laboratories, Arizona, USA, researchers expect that the ERC will help in overcoming the disadvantages like host rejections in currently used bone marrow or umbilical cord stem cell therapy. The advantages of ERC over other stem cells include ease of isolation, high rate of proliferation and high levels of matrix metalloproteases. The pluripotency and the lack of ethical dilemmas associated with embryonic cells make it a good alternative for use in stem cell therapy.
About Medistem – Medistem Laboratories is a biotechnology company focused on the development of non-controversial adult stem cell therapies. The company is sponsoring research targetted at the development of Endometrial Regenerative cells for therapeutic purposes.
References
1. Meng X, Ichem T E, Zhong J, et al. Endometrial regenerative cells: A novel stem cell population. Journal of Translational Medicine. 2007 Nov 15;5(1):57.
2. Wolff EF, Wolff AB, Hongling Du and Taylor HS. Demonstration Of Multipotent Stem Cells In The Adult Human Endometrium By In Vitro Chondrogenesis. Reproductive Sciences. 2007 September; 14(6):524-33.
3. Gargett C, Zillwood R and Schwab K. Characterizing The Stem Cell Activity Of Human Endometrial Cells. Human Reproduction. 2005; 20: i95-i97.
4. Bongaerts G P, Severijnen R S. Stem cells from residual IVF-embryos – Continuation of life justifies isolation. Medical Hypotheses. 2007; 69(3):478-80.
5. Musina R A, Bekchanova E S, Belyavskii A V, Grinenko T S, Sukhikh G T. Umbilical Cord Blood Mesenchymal Stem Cells. Bulletin of Experimental Biology And Medicine. 2007 January; 143(1):127-31.
