EP18.04: Placental villous structure in pre‐eclampsia shows increased syncytial knot density using multiphoton microscopy

Pre-eclampsia (PE) remains an obstetric challenge due to our limited understanding of its pathogenesis. Abnormal placental villous structure is suggested to play a role. Syncytial knots (SKs) are clusters of villous cytotrophoblasts nuclei containing anti-angiogenic factors. This pilot study aimed to study placental villous vasculature in PE using advanced 3D imaging. We used novel multiphoton microscopy (MPM) to image placental villous structure and analyse 3D morphology from normal (N = 4) and pre-eclamptic (N = 4) pregnancies. Using inherent signal (cytoplasm) and fluorescent staining (nuclei and blood vessels) and optical tissue clearing, we visualised large volumes of placental villous tissue with subcellular resolution. Semi-automated analysis was assisted by AI-assisted segmentation for vascular network tracing analysis. There was no difference in gestational age between controls and PE [257 vs. 259 days, p = 0.89]. Significant differences were found between controls and PE for: knot density (N /µL) [1682 vs. 2910, p = 0.04], vascular branch depth [17.77 vs. 5.68, p = 0.02] and vascular branch angle (°) [20.1 vs. 40.8, p = 0.001], respectively. There was no significant difference in knot volume (µm3 × 1000) [Ctrl: 12.4 vs. PE: 15.8], vessel length (µm) [Ctrl: 28.9 vs. PE: 34.8] and vessel diameter (µm) [Ctrl: 9.2 vs. PE: 13.4]. MPM allows for 3D-imaging of placental villi at subcellular resolution, revealing differences in knot density and vascular branch depth in pre-eclampsia. This provides evidence of aberrant vascularisation and a mechanism of abnormal production of antiangiogenic factors in pre-eclampsia. Please note: The publisher is not responsible for the content or functionality of any supporting information supplied by the authors. Any queries (other than missing content) should be directed to the corresponding author for the article.