Immunological localization of syndecan-1 in human endometrium throughout the menstrual cycle

Objective: To examine the expression of syndecan-1 in the endometrium during the menstrual cycle. Design: The expression of syndecan-1 was determined by tissue microarray and immunohistochemistry. Setting: Academic clinical and research laboratories. Patient(s): Seventy-one regularly cycling women who underwent endometrial biopsy. Intervention(s): Endometrial samples representing five stages of the menstrual cycle were used for the study. Main Outcome Measure(s): Semiquantitative analysis by evaluating the intensity of immunohistochemical reactivity of syndecan-1 by using a modified HSCORE. Result(s): Endometrial syndecan-1 was expressed in the luminal and glandular epithelium as well as in the stroma throughout the menstrual cycle in a nonsynchronized fashion. In the luminal epithelium, the expression of syndecan-1 was statistically significantly higher in the mid-secretory phase when compared with the proliferative phase. In the stroma, however, the expression of syndecan-1 was down-regulated after ovulation and remained at a low level through the secretory phases. Differences between the proliferative and mid secretory, as well as between the ovulatory and the early, mid, and late secretory phases, all were statistically significant. Conclusion(s): Syndecan-1 is up-regulated in luminal epithelial cells during the mid-secretory phase and is down-regulated in the stroma during the early to late secretory phases. The differential expression of syndecan-1 coincides with the endometrial remodeling throughout the menstrual cycle.