Human adult stem cells from menstrual blood and endometrial tissue

Abstract

The article “Plasticity of human menstrual blood stem cells derived from the endometrium” by Lin et al. (2011), published in Journal of Zhejiang University-SCIENCE B (Biomedicine & Biotechnology), described a newly identified mesenchymal-like stem cell (MSC) from human menstrual blood known as MenSC. Here we describe the latest findings in this area and clarify the difference between human adult stem cells from menstrual blood and endometrial tissue. MenSCs express pluripotent markers such as octamer-binding transcription factor 4 (Oct-4), stage-specific embryonic antigen 4 (SSEA-4), Nanog, and c-kit, in addition to typical MSC surface markers including cluster of differentiation 9 (CD9), CD29, CD44, CD49f, CD90, CD105, and CD166 (Patel et al., 2008; Borlongan et al., 2010). MenSCs have the ability to differentiate into mesoderm tissues such as cartilage (40%–50%), adipose (60%–70%), and bone (45%), with the degree of differentiation similar to or better than bone marrow-derived MSCs. MenSCs also have the capacity to differentiate into neural and cardiac lineages (Patel et al., 2008). Our animal studies show that the human menstrual blood stem cells can repair several types of damaged cells in vivo (unpublished data). Meng et al. (2007) and Murphy et al. (2008) described the cells from menstrual blood termed endometrial regenerative cells (ERCs) that express CD9, CD29, CD44, CD59, CD73, CD90, CD105, and Oct-4, but lack SSEA-4, Nanog, and c-kit. These cells have been demonstrated to differentiate into nine different cell lineages (cardiomyocytic, respiratory epithelial, neurocytic, myocytic, endothelial, pancreatic, hepatic, adipocytic, and osteogenic). Another source of human adult stem cell from endometrial tissue called eMSC expresses similar MSC markers (Gargett and Masuda, 2010). Both MenSC and eMSC are negative for hematopoietic and endothelial markers such as CD34, CD38, CD45, and CD133 (Patel et al., 2008; Gargett and Masuda, 2010). Major differences between the cells include the invasive process required to retrieve the eMSC as well as the growth properties identified in vitro where eMSC but not MenSC requires growth factors and an extracellular matrix. Independent studies comparing eMSC to MenSC demonstrated 57 significant and differentially expressed genes (unpublished data). Both MenSC and eMSC are similar to bone marrow-derived MSC; however, stromal-derived factor-1 (STRO-1), a marker used to prospectively isolate bone marrow-derived MSC (Gronthos et al., 2003), has not been found in cells from the endometrial tissue (Gargett and Masuda, 2010) or in MenSCs, although decidual cells are known to express STRO-1 (Garcia-Pacheco et al., 2001). MenSCs recapitulate pluripotency properties as an alternative adult stem cell source that circumvents ethical and logistical limitations of embryonic stem (ES) cells. Recent studies reveal great potential of MenSCs for treating stroke (Borlongan et al., 2010) and liver damage (unpublished data).