Changes in the Metabolic Footprint of Placental Explant-Conditioned Culture Medium Identifies Metabolic Disturbances Related to Hypoxia and Pre-Eclampsia

Pre-eclampsia (PE) is a multi-system disorder thought to be mediated by circulating factors released from damaged placental villous trophoblast. There is extensive evidence of changes in the villous tissue in PE, some of which may be replicated by culturing villous tissue in hypoxic conditions. Metabolic footprinting offers a hypothesis-generating strategy to investigate factors released from this tissue in vitro. This study investigated differences in the factors released from villous trophoblast from uncomplicated pregnancies (n = 6) and those with PE (n = 6). In both cases, explanted placental villous fragments were cultured for 96 h in 1% O2 (hypoxia) or 6% O2 (placental normoxia). Metabolites consumed from and released into serum-conditioned culture medium were analysed by Ultra Performance Liquid Chromatography-Mass Spectrometry (UPLC-MS). The relative concentration of 154 features of the metabolic footprint were observed to change in culture medium from uncomplicated pregnancies cultured in normoxic and hypoxic conditions (p < 0.00005). 21 and 80 features were also different in culture medium from PE versus uncomplicated pregnancies cultured in hypoxic and normoxic conditions, respectively (p < 0.00005). When comparing all 4 groups, 47 metabolic features showed a similar relative concentration in PE-derived media cultured in normoxic conditions to conditioned media from normal villous tissue cultured in hypoxic conditions. These data suggest that hypoxia may have a role in the placental pathogenesis of PE. Three areas of metabolism were highlighted for systems biology investigation; glutamate and glutamine, tryptophan metabolism and leukotriene or prostaglandin metabolism.