Context Regeneration of the endometrium in each menstrual cycle is required
for reproduction. Endogenous endometrial stem cells reside in the basalis
layer and serve as a source of cells that differentiate to form the endometrium.
Bone marrow–derived cells have been shown to take on functions outside
the hematopoietic system.
Objective To investigate the possibility that cells of extrauterine origin could
repopulate the endometrium.
Design, Setting, and Patients Endometrium from 4 HLA-mismatched bone marrow transplant recipients
(1998-2002) was evaluated for donor HLA expression. Each recipient had a bone
marrow donor with an HLA type that enabled determination of the origin of
any cell. Endometrial biopsies also were obtained from 4 healthy control women.
Main Outcome Measure HLA type was determined by immunohistochemistry and by reverse transcription–polymerase
Results Donor-derived endometrial cells were detected in endometrial biopsy
samples from all bone marrow recipients and accounted for 0.2% to 48% of epithelial
cells and 0.3% to 52% of stromal cells. None of the controls demonstrated
HLA mismatch in endometrial samples.
Conclusion These findings demonstrate that endometrial cells can originate from
donor-derived bone marrow cells and suggest that nonuterine stem cells contribute
to the regeneration of endometrial tissue.