Stem Cells in Myometrial Physiology

Normal adult tissues contain a small subset of tissue-specific stem cells. These stem cells are capable of self-renewing as well as generating daughter cells that are destined to completely differentiate and thereby support tissue remodeling and repair. The human uterus is an example of how such cell populations support the function of an organ. The uterus primarily consists of endometrium and myometrium, and these tissues rapidly enlarge to support the developing fetus during pregnancy. Uterine enlargement and remodeling can occur more than a dozen times during a woman's reproductive life. The expansion of the gravid uterus is achieved mainly through myometrial hyperplasia and hypertrophy, and these processes suggest an important role for stem/progenitor cell systems. Recently, stem/progenitor cells in the myometrium have been identified and their properties characterized. Here, we discuss some of the properties of myometrial stem/progenitor cells. We also suggest a new model of myometrial physiology and how stem cell systems might contribute to pregnancy-associated uterine remodeling.