Evaluation of suboptimal health status and prospective levels of oxidative stress biomarkers and angiogenic growth mediators with placental anatomy and pathology in normotensive and preeclamptic births

Preeclampsia (PE) is the leading cause of poor maternal and perinatal outcomes in both developed and developing countries. Even though the condition is treatable in the developed world, mothers from developing countries still suffer dramatic events due to limited resources. There is the need to identify readily available measures in addition to existing biomarkers that can predict PE. Thus, this thesis evaluated suboptimal health status (SHS) and prospective levels of oxidative stress (OS) biomarkers and angiogenic growth mediators (AGMs) with placental anatomy and pathology in normotensive and preeclamptic births in a Ghanaian Population. This longitudinal nested case-control study was based on the Ghanaian Suboptimal Health Status Cohort Study (GHOACS) that recruited 593 normotensive pregnant women (NTN-PW) at baseline (10-20 weeks gestation) from the Komfo Anokye Teaching Hospital between June 2017 and May 2019. Suboptimal health status, a subjective health measure was evaluated using the Suboptimal Health Status Questionnaire-25 (SHSQ-25) at baseline, and participants were subsequently classified into suboptimal health status (SHS) and optimal health status (OHS). Baseline participants were followed at 21-31 weeks, 32-42 weeks of pregnancy and 48 hours-2 weeks postpartum. Of the 593, 488 pregnant mothers aged 18-45 years completed the study and 105 were lost to follow-up. Data on sociodemographic, clinical, obstetric and anthropometric characteristics were collected from participants in addition to urine and venous blood samples. The panel of objective biomarkers of AGMs (placental growth factor [PIGF], vascular endothelial growth factor-A [VEGF-A], soluble endoglin [sEng] and soluble VEGF receptor-1 also known as soluble fms-like tyrosine kinase [sFlt-1]) in addition to OS biomarkers (8-epiprostaglandinF2 alpha [8-epi-PGF2α], 8-hydroxy-2-deoxyguanosine [8-OHdG] and total antioxidant capacity [TAC]) were evaluated across the 4-time sampling periods (10-20, 21-31, 32-42 weeks, and 48 hours-2 weeks postpartum) using ELISA. Placenta tissues were collected after delivery and examined for macroscopical, histopathological and immunohistochemical analyses. Data were analysed using SPSS, GraphPad Prism, XLSTAT and R Core. There were significant associations between SHS and imbalances in AGMs and OS (Study I: cross-sectional). The incidence of PE was high among SHS pregnant women (30.7%) compared to OHS pregnant women (8.8%), and SHS was an independent risk indicator for PE (Study II: longitudinal nested case-control). Compared to using the biomarkers alone, combining biomarkers of AGMs and OS, particularly 8- OHdG/PlGF ratio measured at 21-31 weeks (mid-pregnancy) yielded the best area under the curve, sensitivity, specificity, positive and negative predicted values for predicting the likelihood of SHS and OHS pregnant women developing PE (Study III: longitudinal nested case-control). Placental abnormalities and imbalance in the expression of AGMs and OS were associated more with SHS pregnant mothers who developed PE, particularly early-onset PE than late-onset PE (Study IV: case-control). In contrast to normotensive pregnancy, longitudinal profiling of AGMs and OS showed different patterns across the 4-time sampling periods with significant imbalance among SHS more than OHS mothers who later developed PE. Unlike, the single biomarkers, combined AGMs and OS ratios measured at mid-pregnancy yielded more significant hazard ratios in association with PE development (Study V: longitudinal cohort). Thus, combined evaluation of SHS, biomarkers of AGMs and OS together with placental examination increased the understanding of the aetiology, diagnosis and prognosis of PE, and created a window of opportunity for developing potentially predictive, preventive and personalised medicine in both high-and low-resource maternal and child health settings