Assisted reproductive technologies impair the expression and methylation of insulin-induced gene 1 and sterol regulatory element-binding factor 1 in the fetus and placenta

Abstract

To evaluate the cholesterol metabolism linked to assisted reproductive technology (ART) by analyzing the expression levels and DNA methylation patterns of the insulin-induced gene (INSIG), sterol regulatory element-binding protein (SREBP), and SREBP cleavage-activating protein in the fetus and placenta. Experimental research study. An IVF center, university-affiliated teaching hospital. Four patients groups were recruited: pregnancies after IVF/intracytoplasmic sperm injection (ICSI) (n = 55), natural pregnancies (n = 40), multifetal reduction after IVF/ICSI (n = 56), and multifetal reduction after controlled ovarian hyperstimulation (COH) (n = 42). Expression and DNA methylation of INSIG-SREBP- SREBP cleavage-activating protein in the fetus and placenta samples were determined. The expression and DNA methylation patterns were tested by real-time quantitative polymerase chain reaction (PCR) and pyrosequencing. In the ICSI treatment group, significantly higher levels of triglycerides and apolipoprotein-B were observed in cord blood compared with controls. Meanwhile, in ICSI-conceived fetuses, the expression of INSIG1 was significantly higher, and methylation rates were lower, than in the IVF and control groups. Furthermore, in the placenta, the INSIG1 and SREBF1 transcripts were also significantly higher with lower methylation rates in the ICSI group than in the IVF and control groups. Our results indicated that the dysregulation of INSIG1 and SREBF1 caused by ART were observed not only in the fetus but also in the placenta, primarily in the ICSI group. However, the long-term sequelae of this dysregulation should be closely followed.