Placental vascular remodeling in preeclampsia: A three-dimensional analysis of microvascular alterations across disease severity.

INTRODUCTION

This study aimed to characterize placental vascular morphological alterations across different severities of preeclampsia (PE) using advanced three-dimensional (3D) imaging and histological techniques, exploring correlations between placental microvascular changes and disease severity.

METHODS

A prospective observational study included 122 singleton pregnancies, categorized as normal (n = 45), mild PE (n = 51), or severe PE (n = 26). Placental vascular casts were created through modified resin casting, followed by 3D computed tomography (CT) reconstruction, scanning electron microscopy (SEM), and histopathological analysis. Vascular morphometry, volume, density, and microstructural features were quantitatively assessed.

RESULTS

Significant intergroup differences in placental vascular characteristics were identified. Compared with normal placentas, mild PE exhibited compensatory increases in total vascular volume, primarily due to venous expansion, while severe PE demonstrated significantly reduced vascular volumes and grades (P < 0.01). Morphometric analysis indicated progressive narrowing of distal venous (V3-V5: 24.9-32.5 %) and arterial branches (A3-A4: 19.7-23.2 %) correlating with PE severity. Vascular density analysis showed a marked stepwise reduction from normal to severe PE groups, with venous networks being most affected (31.1 % decrease, P < 0.001). SEM and histopathological examinations confirmed severe vascular rarefaction, abnormal vessel morphology, and hallmark pathological changes in severe PE. Further correlation analysis demonstrated that total placental vascular density was positively associated with neonatal birth weight (ρ = 0.523, P < 0.001), MCA peak systolic velocity (ρ = 0.218, P = 0.042), and 1-min Apgar score (ρ = 0.344, P = 0.005), while showing significant negative correlations with umbilical artery PI (ρ = -0.387, P = 0.003), NICU admission (ρ = -0.297, P = 0.011), maternal serum creatinine (ρ = -0.262, P = 0.027), and maternal ALT levels (ρ = -0.233, P = 0.038).

DISCUSSION: Placental microvascular alterations correlate significantly with preeclampsia severity. Our findings highlight distinct vascular remodeling patterns in PE and provide essential morphological evidence supporting microcirculatory dysfunction as a key pathological mechanism in preeclampsia progression.