Autologous endometrial co-culture (AECC) in patients with IVF failure: correlations of outcome with IGF-1

Abstract

Objective: Co-culture of embryos with monolayers of AECC has been shown to improve outcome for patients with multiple implantation failures after IVF-ET. Presumably, this effect is mediated through the production of trophic factors expressed by these helper cell lines. The endometrial cells elaborate IGF-1. In laboratory animals, IGF-1 expression by endometrial cells has been demonstrated to correlate with embryonic development. The specific aim of this study was to determine if IGF-1 levels as measured in the supernatants of conditioned media (CM) of embryos co-cultured in AECC is predictive of IVF outcome. Design: Prospective trial. CM from the AECC cells exposed or non-exposed to human embryos was collected in 41 patients and assayed for the presence of IGF-1 and correlated with outcome. Materials and Methods: During a luteal phase biopsy (5–10 days after LH surge) made prior to the treatment cycle, glandular (G) and stromal (S) endometrial cells were isolated by enzymatic digestion and separated based on differential sedimentation rates. These cells were cryopreserved, then plated as a 50%/50% combination of G and S cells prior to embryo exposure. The conditioned medium (CM) was changed every 2 days. Embryos were randomly grown on ECC or conventional media if more than 6 oocytes normally fertilized. Otherwise, all embryos were grown on AECC. IGF-1 levels were measured utilizing an immunoenzymetric assay. Background levels of IGF-1 were also determined from media alone (C-2 media supplemented with 15% patient’s serum). Statistics included Wilcoxon signed rank test, Mann-Whitney U test and Chi-square. Results: The pregnancy rate was 65.8% (27/41). The clinical pregnancy rate (Fetal heart activity) was 56.1% (23/41). The mean age of the patients was 36.6 (3.8) years. A total of 10.7 (4.7) mean oocytes were obtained at the retrieval. On average, 3.4 (1.3) embryos were replaced. Exposure or non-exposure to an embryo did not result in differing levels of IGF-1 in the CM. Embryos grown on ECC demonstrated a significant improvement in number of blastomeres and fragmentation (frag) when compared to embryos grown in conventional media without AECC (6.5 + 1.2 vs. 5.4 + 1.2 blastomeres and 14.6 % + 9.3 vs. 26.5% + 9.4 frag; P < 0.05). When IGF-1 was greater than 2ng/mL in the CM, the embryos grown in ECC were of improved quality as compared to the embryos grown only in conventional media. A trend towards a higher level of IGF-1 was found in the CM form embryos that resulted in a clinical pregnancy. Conclusion: We have demonstrated a significant improvement in blastomere number and fragmentation with AECC. IGF-1 is expressed by the cells in the AECC. IGF-1 appears to play an important role in the AECC system.