Bone marrow-derived stem cells in the human endometrium

The human endometrium is one of the most dynamic structures in the human body. The remarkable tissue remodeling that occurs in the endometrium is unparallelled in any other organ. Under the influence of the ovarian steroids hormones – estrogen and progesterone – the uterus undergoes dramatic changes in order to prepare for embryo implantation every 28 days. These modifications occur in multiple cells types, including the epithelium, the underlying stroma and the vasculature. The molecular and cellular modifications that occur during the period of these structural changes result in a functional window of receptivity for a human embryo to attach to the endometrium.1