Protein profiling of human endometrial tissues in the midsecretory and proliferative phases of the menstrual cycle

Objective: To identify the proteins displaying differential expression in midsecretory phase endometrium as compared with proliferative phase endometrium. Design: Prospective study with two groups of women in the midsecretory or proliferative phase. Setting: Clinical research outpatient department. Patient(s): Healthy, regularly cycling women of proven fertility. Intervention(s): Collection of endometrial biopsy samples. Main Outcome Measure(s): image analysis software was used to compare two-dimensional protein maps of midsecretory phase endometrial tissues (MSE) with maps of proliferative phase endometrial tissues (PROE) and midsecretory phase uterine fluids (MSU). Matrix-assisted laser desorption/ionization time of flight in tandem (MALDI-TOF-TOF) analysis was carried out to identify eight proteins that were differentially expressed between the two phases and also to identify the spots that shared similar coordinates in the two-dimensional maps of MSE and MSU. Result(s): Densitometry analysis and subsequent MALDI-TOF-TOF analysis revealed up-regulation of calreticulin, the beta chain of fibrinogen, adenylate kinase isoenzyme 5, and transferrin in the PROE and of annexin V, alpha 1-antitrypsin, creatine kinase, and peroxidoxin 6 in MSE compared with the other phase. Superimposition of the two-dimensional maps of MSE on those of MSU revealed the presence of heat-shock protein 27, transferrin, and alpha 1-antitrypsin precursor in both endometrial tissues and uterine secretions. Conclusion(s): Differentially expressed proteins identified in the present study could be of relevance in endowing the endometrium with receptivity. (Fertil Steril (R) 2009;92:1091-103. (C)2009 by American Society for Reproductive Medicine.)