However, the hCG-induced increase in the VEGF level was reduced in Tie1-silenced SVOG cells compared to mock-silenced cells (Fig. 2d, e), indicative of the importance of VEGF and Ang-Tie signaling pathways in the cellular events of OHSS, which is consistent with the literature29. This evidence concerns the gene TIE1 and ovarian hyperstimulation syndrome.