Circulating MMP-7 and VEGF as potential predictive biomarkers for recurrent implantation failures.

Recurrent implantation failure (RIF) is considered to be one of the major limiting factors of assisted reproductive technology (ART) programme success. The current study focused on the investigation of matrix metalloproteinases (MMPs), tissue inhibitors of MMPs (TIMPs), cytokines and cell adhesion molecules in peripheral blood (PB) and follicular fluid (FF) obtained from 44 women aged between 25 and 39 years old and undergoing intracytoplasmic sperm injection (ICSI). These women were divided into two groups: 22 RIF women with embryo implantation failures after the transfer of at least four fresh or frozen-thawed good quality embryos in a minimum of three ICSI cycles, and 22 ICSI success women (controls) who achieved a clinical pregnancy at their first ICSI attempt. The PB and FF samples were obtained from each patient on the day of oocyte retrieval. MMP-1, -2, -3, -7, -9, TIMP-1, -2, vascular endothelial growth factor (VEGF), leukaemia inhibitory factor (LIF), vascular cell adhesion molecule 1 (VCAM1) and intercellular adhesion molecules 1 (ICAM1) were analyzed using enzyme-linked immunosorbent assay of PB and FF. Our results showed significant decreases in PB MMP-7 and PB VEGF in the RIF group compared with controls [281.11 (33-614) pg/ml vs 119.92 (27-441) pg/ml; P-value = 0.030] and [82.54 (25.94-210.20) pg/ml vs 30.93 (13.62-193.33) pg/ml; P-value = 0.022; respectively]. Receiver operating characteristic (ROC) curve analysis showed informative area under the curve values for PB MMP-7, as well as for PB VEGF, making them able to be proposed as biomarkers of the RIF. Therefore, circulating MMP-7 and VEGF seem to play an interesting role in embryo implantation in in vitro fertilization (IVF)/ICSI cycles and could be proposed as circulating biomarkers of the RIF. These results could be helpful for clinicians and patients to choose the best rescue strategy and treatment to minimize implantation failure in women undergoing IVF/ICSI procedures after the first attempt.