Reproduction Abstracts

Introduction: Our previous 2D-DIGE studies of uterine fluid, identified differing isoform distributions of the serine protease inhibitor α-2-macroglobulin (A2M) resulting from post-translational modification (PTM’s), among fertile and infertile women. Carbohydrate side chains are a key PTM, often conferring recognition between protein partners, e.g. enzyme and inhibitor. Altered PTM’s may potentially change the interactions of A2M with proteases, effectively altering the proteolytic environment of the uterine cavity and impacting embryo-endometrium interaction.

We hypothesised that specific A2M glycoforms may be expressed during the phases of the menstrual cycle and serve as markers of endometrial receptivity. Our aim was to identify A2M glycoforms that may discriminate between fertile and infertile, receptive and non-receptive endometrium.

Materials and methods: A2M glycoform distribution was determined in uterine lavage from proliferative and secretory phases of fertile and infertile women using 21 lectins in arrays with an A2M specific antibody. For the most promising lectins, assays were developed on Luminex and a cohort of fertile and infertile women assayed.

Results and discussion: DBA and GSLI binding glycoforms were significantly elevated in the secretory phase compared to proliferative phase of fertile women; however infertile women showed significantly lower secretory phase concentrations. LEL binding forms were significantly reduced among the infertile cohort during the proliferative phase.

Thus, specific glycoforms of A2M may be useful as markers of endometrial receptivity since changes with cycle phase and with fertility status were demonstrated.