Proteomic comparison of intact and fetoscopy-induced fetal membrane defect sites

Background: Iatrogenic preterm premature rupture of fetal membranes (iPPROM) following fetoscopic interventions remains a major barrier to the advancement of fetal therapies. The mechanisms underlying iPPROM are poorly understood, but the inability of fetal membrane (FM) defects to heal spontaneously likely plays a key role, contrasting with the regenerative potential of amniotic membranes in other contexts. Methods: To assess the impact of fetoscopic procedures on FMs, tissue samples from patients who underwent laser surgery for twin-to-twin transfusion syndrome (16-27 weeks gestation, n = 8) were collected after cesarean delivery at 29-35 weeks. Samples were categorized by proximity to the trocar site and analyzed using proteomic and histological methods. Results: While differential expression analysis in the amnion revealed no significant changes, pathway enrichment indicated increased collagen deposition at defect sites. In the chorion, seven differentially expressed proteins were identified, largely linked to enhanced intercellular contact stability. These findings suggest the amnion may respond to mechanical stress by reinforcing structural integrity through collagen deposition, while the chorion may attempt to stabilize cell junctions. However, no other signs of tissue regeneration were observed. Conclusion: This study provides molecular and cellular evidence that FMs lack a substantial healing response post-surgery, underscoring the need for biologically informed repair strategies. Impact: By combining untargeted proteomics with histological and qPCR evaluations, this study demonstrates subtle molecular and cellular changes in fetoscopy-induced fetal membrane defects at the time of delivery. This indicates minimal molecular and cellular healing mechanisms in the fetal membranes. This underscores the potential for sealing FM defects after fetoscopy to prevent amniotic fluid leakage, thereby reducing the incidence of intra-amniotic preterm rupture of membranes.