Circulating Insulin-Like Growth Factor Binding Protein-5 Levels and Promoter Variation Are Associated with In Vitro Fertilization and Embryo Transfer Outcome (IVF-ET) in An Iranian Population

Background: Infertility is a global social and economic con-cern. Successful implantation requires an appropriate interac-tion between the embryo and the endometrium. In vitro fer-tilization (IVF) outcome depends on the completion of three successive steps: ovarian stimulation, embryo quality and most importantly, embryo implantation in the endometrium. Insulin-like growth factor (IGF) was shown to improve the clinical pregnancy rate. IGF is recognized as a potent growth factor because of its ability to promote the proliferation endometrial and trophoblastic cells and embryo implantation. The IGF axis includes two homologues IGFs (IGF-1 and -2), at least six high affinity IGF binding proteins (IGFBPs) including IGFBP-1 to IGFBP-6, and two membrane bound IGF receptors (IGFR1 and 2). IGFs in circulation and other physiological fluids are asso-ciated with IGFBPs.The aim of this study was to examine the association of IGFBP-5 circulation levels and gene polymor-phisms with IVF-ET outcome in an Iranian population.Materials and Methods: In this case–control study, 100 infer-tile women who had unsuccessful IVF (IVF–) history and 110 infertile women who had successful IVF outcome (IVF+) as controls were included. The samples were collected from Mehr fertility institute, Rasht, Iran. Genomic DNA was extracted from peripheral blood. Genotying was performed by polymer-ase chain reaction-restriction fragment length polymorphism (RFLP- PCR). The circulating concentration of IGFBP-5 was measured by enzyme-linked immunosorbent assay (ELISA).Results: Statistical analysis was performed using the χ² test and the Med Calc version 12.1.4. The results from allele and geno-type frequencies showed that there are significant differences between (IVF+) and (IVF-) groups. Furthermore, we showed that there is a significant change in serum IGFBP-5 levels in IVF– as compared to IVF+ (P<0.001).Conclusion: It is thus concluded that IGFBP-5 serum levels and promoter polymorphism are associated with IVF-ET out-come in our population. Further studies are needed to confirm the role of IGFBP-5 in IVF-ET outcome.

Keywords:

IGFBP-5 , Genetic Polymorphism , Serum , IVF-ET Outcome