Endometrial endothelial cells are derived from donor stem cells in a bone marrow transplant recipient

Abstract

The endometrium is a dynamic, cyclically regenerating tissue: a unique model of physiological angiogenesis in adults. However, the source of new endothelial cells (ECs) for vessel regrowth is obscure. We studied if male EC could be detected in the endometrial blood vessels of female human or mouse recipients of haematological stem cells from male donors. Endometrial biopsies, obtained from one patient after non-myeloablative allogeneic bone marrow transplantation and two controls, were analysed by immunohistochemistry of CD34 and VEGFR2 antibodies for the immunophenotyping of EC, and FISH probes for the detection of donor cells. Chimerism was analysed using real-time PCR. The same experiment was also applied on the animal model. At the time of a Caesarean section in a female bone marrow transplanted patient, an average 14% of her endometrial EC were donor-derived. One year later, that figure was 10%. In contrast, none of two non-transplanted females demonstrated a mismatch in endometria at Caesarean section. In samples from female mice, harvested 40 days after a haematological stem cell transplant, a 6% average of donor-derived EC was detected. Bone marrow-derived endothelial progenitors contribute to the formation of new blood vessels in the endometrium.