Proteomic patterns in plasma and peritoneal fluid of women with endometriosis.

Objective: Endometriosis is associated with an inflammatory peritoneal environment, where multiple cytokines and growth factors are found at elevated levels. The aim of this study is to identify the proteomic patterns in plasma and peritoneal fluid (PF) of women with endometriosis. Design: Cross-sectional study. Materials and Methods: PF and plasma samples were obtained from 23 women with endometriosis and 4 women with unexplained infertility undergoing laparoscopy. PF and plasma proteins were separated and characterized in terms of their molecular weight (M(r)) and isoelectric point (pI) using two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) to yield protein maps. Protein spots were detected between pH 4 and 7, M(r) 15 kD and 150 kD. Phoretix 2D software was used to digitize and compare the protein spots detected on silver-stained gels. The volume of each was calculated by considering spot area and staining intensity. The quantification of each spot of interest was expressed as normalized percent volume. Results: A mean number of 428 protein spots per gel was detected in the PF of women with endometriosis. Two spots were classified as PF-specific because they were not observed in the plasma. All the protein spots present in PF of women with endometriosis were apparently present in PF of infertile women. Six protein spots had significant increased expres- sion in women with endometriosis when compared with infertile controls. Seven protein spots had significant decreased expression in women with endometriosis when compared with infertile controls. When the patients were grouped according to the Revised American Fertility Society classification of endometriosis, two-dimensional gels showed clear differences between protein patterns of women with different stages. One protein spot was significantly increased in women with stage I/II compared with those with stage III/IV. Five protein spots were significantly increased in women with stage III/IV compared with those with stage I/II. Conclusion: These preliminary data, to our knowledge, define for the first time the proteome of PF and plasma in women with endometriosis. Pathological changes related to different stages of endometriosis seem to be reflected in the proteomic patterns of PF. These findings pave the way for a more detailed characterization of the structure and function of the identified protein spots.