Table 1.

Summary of Stem Cell Populations Described in the Human Endometrium

Description	Stem cell type	Niche	Differentiation	Properties	Markers	Ref.
Endometrial-myometrial junction stem cells	Resident stem cells	Endometrial-myometrial junction and endometrial basalis	Myometrial smooth muscle cells Endometrial cells (epithelium, stroma, microvasculature)	Proliferation is hormone independent	Tritiated thymidine slow cycling cells.	3,4,10,11
Side population endometrial stem cells	Mesenchymal stem cells Epithelial stem cells Endothelial progenitor cells	Endometrial basalis and functionalis, and vessel locations	Endometrial cells (epithelium and stroma) Decidualization-in vitro mesodermal differentiation In vivo tissue reconstitution.	Telomerase activity Telomere length Cloning efficiency Quiescent cell population and side population not from bone marrow origin	CD105, CD146, CD31, CD34, CD144, CD90, BCRP1, MDR1, c-kit, and Oct-4.	13,21–24,51
Endometrial stromal/mesenchymal stem cells	Mesenchymal stem cells Endothelial progenitor cells	Endometrial perivascular located in the basalis and functionalis	In vitro mesodermal differentiation In vivo tissue reconstitution.	Colony-forming assays Angiogenic properties Immunoregulatory properties	CD146, PDGFRB, W5C5-SUSD2, CD31, CD29, CD44, CD73, CD90. and CD105.	12–15
Endometrial epithelial stem cells	Epithelial stem cells	Glands in the basalis	Gland-like structures	Methylation patterns and quiescent cell population	SSEA-1, Nanog, Oct-4, SOX9, N-cadherin and Lgr5.	16–19
Menstrual blood stem cells	Mesenchymal stem cells Epithelial stem cells Endothelial progenitor cells	Endometrial functionalis	Multilineage differentiation (mesodermal, neuronal, and cardiac lineage)	High proliferative capacity and cloning efficiency	CD44, CD90, Oct-4, Nanog, SOX2, SSEA-4, c-kit, CD29, CD73, CD34 and CD105.	25,92–94