Putative stem cell activity of human endometrial epithelial and stromal cells during the menstrual cycle.

OBJECTIVE: To determine whether menstrual cycle stage or activity has an effect on the clonogenic activity of human endometrial epithelial and stromal cells.
DESIGN: Clonal analysis of human endometrial epithelial and stromal cells derived from full-thickness endometrium.
SETTING: University research laboratory. PATIENT(S): Twenty-six women of varying age and race undergoing hysterectomy for nonendometrial pathologies. INTERVENTION(S): Full-thickness human endometrial tissue was dissociated into single cells. Epithelial and stromal cells were separated using magnetic beads, and cloning assays were performed in serum-containing or growth factor-supplemented serum-free medium. MAIN OUTCOME MEASURE(S): Clonogenic activity of epithelial and stromal cells. RESULT(S): Clonogenicity of epithelial and stromal cells did not vary significantly between proliferative, secretory, and inactive endometrium. However, epithelial and stromal cells did show a trend for greater numbers of clonogenic cells in secretory and proliferative endometrium respectively. A large variation between samples was observed, which may have masked any significant differences. CONCLUSION(S): We found that clonogenicity does not vary from the proliferative to secretory stage of the menstrual cycle, or between active, cycling and inactive endometrium for both epithelial and stromal cells. We have demonstrated for the first time that inactive endometrium contains clonogenic epithelial and stromal cells.