A study of metabolic and inflammatory pathways throughout gestation

The effect of metabolic and inflammatory parameters on pregnancy success in terms of implantation, metabolic adaptation to pregnancy and fetal programming is yet to be fully understood. This thesis explores the activity of metabolic and inflammatory pathways in pregnancy, highlighting their importance throughout gestation. In a cell culture study, a model of in vivo blastocyst-uterine adhesion to study the effect of insulin during uterine implantation was explored. JAR spheroid-RL95-2 monolayer adhesion reached 98% by 24 hours in the absence of insulin. A low dose (0.03nM) of added insulin concentrations resulted in 26% adhesion, or 74% inhibition; a high level (0.24nM) inhibited the JAR spheroid-RL95-2 monolayer adhesion by 9%. Therefore insulin did not have a dose-dependent on JAR spheroid-RL95-2 monolayer adhesion in the cell culture model of implantation. Polymerase chain reaction (PCR) studies revealed laminin α1 RNA detection on JAR cells only, CD44 on RL95-2 cells only, no trophinin on both cell types, FBLN-1 and -2 on JAR and FBLN-1 on RL95-2 cells only and an insulin receptor in both cell types. Western blot and immunohistochemistry (IHC) studies showed laminin α1 detection and stains on the JAR cell extracellular matrix. In a prospective human study, the metabolites of lipid and carbohydrate metabolism and inflammatory mediators very early (between day 0 and day 45) in gestation and their link to successful pregnancy in women undergoing natural cycle frozen embryo transfer (FET) in assisted conception, was investigated. Plasma triglyceride (TG), total cholesterol (TC), high-density lipoprotein cholesterol (HDL-C), glucose, c-reactive protein (CRP) and non-esterified fatty acid (NEFA) were measured on routine biochemistry; insulin, interleukin (IL)-6, plasminogen activated inhibitor (PAI)-1 and PAI-2 on ELISA; IL-8 (CXCL8), CCL2, CCL3, CCL4 and CCL11 on BioPlex; and human chronic gonadotrophin (hCG) on an Immulite system. For all 196 FET cycles, participants' demographics and plasma parameters of pregnant (n=36) and non-pregnant (n=106) women were explored. Neither obesity, the plasma parameters nor insulin resistance were predictive of successful pregnancy, but ICSI (predominately associated with male factor infertility) was. Overall, the hCG, insulin, rebound TG and HDL-C (except TC), homeostasis model assessment (HOMA), CRP and PAI-2 levels were higher, whereas CXCL8, CCL2, CCL11 and PAI-1 were significantly lower by day 45. Baseline obesity related to positive changes in plasma insulin, HDL-C and HOMA and negative changes in CXCL8, CCL3 and CCL4. In a cross-sectional study in late pregnancy, offspring's reflection of parameters in women with preeclampsia (PE) (n=29) and intrauterine growth restriction (IUGR) (n=14), compared to BMI-matched healthy groups (n=87) and (n=42), respectively, was explored. Fetal cord was found to be hyperlipidaemic, normoglycaemic and had reduced inflammatory response, while mothers who suffered PE had altered plasma TG, TC, NEFA, glucose, leptin and IL-10 compared to controls. IUGR babies were dyslipidaemic. The role of cholesterol transporters was assessed in PE (n=20) and IUGR (n=9) BMI-matched controls (n=20 and n=9) respectively. Among fifteen steroidogenic acute regulatory protein (STAR)-related lipid transfer domains, only STARD6 and STARD15 were not detected in the placenta via PCR. IHC studies were also explored on the placentae. The real-time PCR (RT-PCR) of messenger RNA of low-density lipoprotein receptor (LDLR), STARD3 and ATP-binding cassette A1 (ABCA1) without protein were higher in PE compared to controls. LDLR, STARD3 and ABCA1 localisation and detection were consistent to placental lipid (cholesterol) transport systems. In summary, all this led to the conclusion of the importance of metabolic and inflammatory pathways in all stages of pregnancy in leading to pregnancy success; these pathways may influence implantation, adaptation to pregnancy and, potentially, fetal programming of offspring.