Placental Gene Silencing of sFlt-1 and Soluble Endoglin as a Precision Therapeutic Strategy for Severe Early-Onset Preeclampsia

Abstract

Severe early-onset preeclampsia, defined by disease onset before 34 weeks of gestation, remains one of the most challenging obstetric complications because the only definitive treatment, placental delivery, often necessitates premature birth to safeguard maternal health. Advances in understanding its pathogenesis have identified placental ischemia and maladaptation as key drivers of excessive production of the antiangiogenic factors soluble fms-like tyrosine kinase-1 (sFlt-1) and soluble endoglin (sEng). These circulating mediators disrupt vascular endothelial growth factor, placental growth factor, and transforming growth factor-β signaling, resulting in widespread maternal endothelial dysfunction, hypertension, proteinuria, and multiorgan injury. As the placenta is the principal source of these pathogenic factors and a transient organ, targeting their placental production represents a rational disease-modifying strategy rather than merely alleviating clinical manifestations. This review critically examines the biological and clinical rationale for placental silencing of sFlt-1 and sEng as a therapeutic approach for severe early-onset preeclampsia. We review the evidence that they are causal mediators and biomarkers, the limitations of current management strategies, and the mechanistic basis for correcting the antiangiogenic imbalance at its source. Emerging preclinical studies using rodent and nonhuman primate models show that decreased placental sFlt-1 expression lowers circulating antiangiogenic burden and ameliorates disease phenotypes while highlighting the potential and challenges of concomitant sEng targeting. However, no placental gene-silencing therapy has yet entered routine clinical practice, underscoring that current evidence remains predominantly preclinical. We also cover maternal-fetal safety, therapeutic timing, translational hurdles, and ethical considerations and conclude that placental gene-silencing therapies have moved from theoretical concepts to promising preclinical therapeutic candidates for precision medicine in pregnancy.