| Summary: | <p><strong>Introduction:</strong> Preeclampsia (PE) is a complication of pregnancy that affects 2-8% of women worldwide. It is one of the leading causes of maternal deaths and premature birth. PE is characterised by high blood pressure, proteinuria, and/or end-organ damage after 20 weeks of gestation. The placenta is believed to play a crucial role in the development of PE, with altered extracellular vesicle (pEV) being released into the maternal circulation. However, the potential diagnostic utility of pEV for early detection of PE remains unclear. Furthermore, the impact of pEV on renal functions, specifically regarding proteinuria and reduced renal function in PE, is not fully understood. This thesis aims to address these questions and shed light on the involvement of pEV in PE pathogenesis.</p>
<p><strong>Aim:</strong> My research investigates the potential of utilizing pEV as a diagnostic tool for early detection of preeclampsia, while also examining the impact of pEV on renal functions in individuals with normal pregnancy (NP) and PE.</p>
<p><strong>Methodology:</strong> I have investigated the potential diagnostic value of pEV for early detection of PE, using a novel EV characterising device named ExoCounter. Additionally, I conducted comprehensive studies to understand the functional and proteomics effects of pEV derived from NP and PE on podocytes, a type of renal cells.</p>
<p><strong>Results:</strong> The serum of women who developed early onset preeclampsia (WWD-EOPE) during the first trimester showed significantly higher counts of CD10-placental alkaline phosphatase (PLAP) and CD63-PLAP placental small extracellular vesicle (psEV) compared to normal pregnancy (NP). While previous studies have demonstrated that the levels of CD10-PLAP and CD63-PLAP placental extracellular vesicles (pEV) are elevated in PE compared to NP in the third trimester, this is the first study to report that this elevation can also be detected as early as the first trimester. These psEV can serve as biomarkers to identify patients at risk of developing EOPE, allowing for early intervention. Additionally, psEV isolated from ex vivo placental dual-lobe perfusion were found to be internalized by podocytes. Flow cytometry analysis revealed no significant difference in the levels of podocyte-internalized EV from NP psEV and PE psEV. NP psEV induced increased migration ability in podocytes, potentially through mechanisms involving enhanced nephrin expression and strengthened cytoskeleton filamentous F-actin. On the other hand, PE psEV impaired podocyte adhesion ability and did not stimulate migration, potentially due to the formation of stressed F-actin. Subsequent analysis using proteomics analysis and functional enrichment revealed that differentially expressed proteins (DEPs) in podocytes treated with NP psEV were found to be associated with cellular component organization or biogenesis, intracellular transport, and mitochondrial functions. Conversely, DEPs in podocytes treated with PE psEV were potentially involved in metabolic processes, nitrogen compound metabolic processes, and gene expression.</p>
<p><strong>Conclusions:</strong> The findings presented in this thesis have advanced the knowledge of psEV in the context of preeclampsia, offering insights into their diagnostic potential and proposing effective methodologies for their evaluation. Furthermore, the examination of NP and PE psEV’s impact on podocyte functions has provided valuable insights that could guide the development of future therapeutic strategies to enhance maternal and fetal well-being.</p>
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