Do cytokine levels in the supernatant from conditioned media (CM) of embryos grown in autologous endometrial coculture (AECC) correlate with pregnancy outcomes after in vitro fertilization (IVF)?

Abstract

AECC has been shown to improve outcomes in patients with multiple failures after IVF. AECC works to enhance in vitro conditions in several ways including the elaboration of cytokines by endometrial cells. IL-2, IL-12p70, IL-4, IL-5 are known to be produced by the endometrium. The aim of this study was to determine the association of these cytokines with IVF outcomes. In 92 IVF patients, supernatant from AECC was tested for the presence of IL-2, IL-12p70, IL-4 and IL-5. From a luteal endometrial biopsy performed prior to IVF, glandular and stromal cells were isolated, separated, then plated in a 50/50 combination. After one week in which the culture medium was changed every 2–3 days, the cells were cryopreserved to be thawed 3 days prior to embryo placement. If more than 6 oocytes fertilized normally, embryos were randomly grown on AECC cells (75%) and conventional media (25%), otherwise, all embryos were grown on AECC. Immediately after embryo removal before transfer, the CM was collected and cryopreserved. Only CM after embryo exposure was tested as previous research has shown that the presence of embryos does not alter cytokine levels from CM with AECC. Cytokine levels were measured utilizing commercially available enzyme linked immunoassays. The average age of the patients was 37.2 ± 4.4 years. Mean numbers of MIIs, 2PNs, and embryos transferred were 12.0 ± 6.6, 7.3 ± 4.8, and 3.3 ± 1.4 respectively. The clinical pregnancy rate was 44.6% and implantation rate was 22.9%. Embryos grown on AECC demonstrated a significant improvement in the mean number of blastomeres and mean fragmentation rate when compared to embryos grown in conventional media (5.8 ± 1.2 vs. 5.0 ± 1.9; 10.5% ± 7.1 vs. 17.6% ± 13.8; P<0.01). The presence of IL-2, IL-12p70, IL-4 and IL-5 was detected in 84.8%, 94.6%, 98.9%, and 95.7% of samples, respectively. Although cytokine levels in the CM did not correlate with either mean number of blastomeres or mean fragmentation rate, IL-12p70 levels were decreased in CM from embryos of good quality in comparison to levels in embryos of poor quality (1.0 ± 1.0 vs. 2.0 ± 3.1; P<0.05). No association was found between cytokine levels and pregnancy outcomes. Significant improvement in blastomere number and fragmentation rate was achieved with AECC. All of the evaluated cytokines were expressed by cells in the AECC. Cytokine levels did not correlate with pregnancy outcomes. However, IL-12p70 levels were decreased in CM from good quality embryos.