Objective: To explore the possibility that endometrial injury modulates the expression of specific genes that may increase uterine receptivity.
Design: Controlled clinical study.
Setting: Clinical IVF unit and academic research center.
Patient(s): IVF patients with 28- to 30-day menstrual cycles.
Intervention(s): Endometrial biopsies from two groups of patients were collected on days 20-21 of their spontaneous menstrual cycle. The experimental, but not the control, group underwent biopsies on days 11-13 and 21-24 of their preceding cycle.
Main outcome measure(s): Global endometrial gene expression and specific analysis of uroplakin Ib (UPIb) mRNA level throughout the menstrual cycle.
Result(s): Local injury modulated the expression of a wide variety of genes. One of the prominently up-regulated genes was the bladder transmembranal protein, UPIb, whose expression by the endometrium is shown here for the first time. Endometrial UPIb mRNA increases after biopsy in the same cycle wct 2with an additional elevation in the following cycle. Immunohistochemical analysis localized the UPIb protein to the glandular-epithelial cells. Genes encoding other membrane proteins such as adipose differentiation-related protein and mucin 1, transmembrane, were also up-regulated.
Conclusion(s): The biopsy-induced increase in the expression of UPIb and other genes encoding membrane proteins supports the possible importance of the membrane structure and stability during implantation. The specific role of UPIb in uterine receptivity should be elucidated.