Celular and molecular characterization of stem cells from pelvic endometriosis

The endometrium contains stem cells that possibly contribute to the regeneration of the functional layer during the mensal cycling. Different kinds of stem cells were isolated from endometrium and endometriotic implants. The monoclonal origin of endometriotic implants indicates that stem cells may have a role in the endometriosis pathogenesis. We isolated a mixed cells pool containing at least one stem cells population from healthy and endometriosis endometrium. These cells presented the markers CD90, CD73, CD105, CD44 and CD146, being able to differentiate into adipogenic, osteogenic and chondrogenic lineages and not responding to progesterone stimulus. The endometriosis stem cells expressed the CD34 naïve stem cells marker, presented higher proliferative rates than healthy ones and were able to form long lasting cells aggregates (spheroids) in tridimensional cultures. The endometrium with endometriosis had a unique stem cell population, reinforcing the hypothesis that stem cells play a key role in the endometriosis pathogenesis. 2. INTRODUCTION Stem cells are undifferentiated cells defined by their functional ability to self-renew and to differentiate into multiple cell lineages, as well as by plasticity and clonogenic potential. They were found abundantly in embryonic and fetal tissues and are also present in small amounts in the majority of the adult tissues; differing between each other only in the clonogenic and differentiation potential. Adult stem cells occur in niches that balance self-renewal with lineage selection and progression during tissue homeostasis