Plasminogen Activator Inhibitor-1 as a Marker of Esophageal Functional Changes in Pediatric Eosinophilic Esophagitis

Background & Aims: Esophageal remodeling in eosinophilic esophagitis (EoE) can lead to esophageal rigidity with eventual luminal compromise and stenoses. Gauging esophageal functional alterations in EoE is challenging. An epithelial marker of functional remodeling would impact EoE management. Methods: Esophageal biopsy specimens from children with and without EoE and primary human esophageal epithelial cells were used for PAI-1 immunohistochemistry, and cell proliferation experiments. PAI-1 immunostaining and basal cell hyperplasia were assessed in the context of concurrently obtained esophageal compliance measures on endoscopic functional lumen imaging probe (EndoFLIP). Results: EndoFLIPs were performed in 45 children (32 with and 13 without EoE). Epithelial PAI-1 was increased in patients with active EoE versus inactive or control patients (P < .01). Esophageal compliance was lower in EoE patients versus controls, particularly in the proximal esophagus (P < .001). Proximal compliance was the strongest predictor of EoE (AUROC 0.88, 95% CI 0.77, 0.98) with esophageal compliance of less than 2.6%mL/mmHg demonstrating 82% sensitivity and 84% specificity for EoE. PAI-1 inhibition significantly diminished esophageal epithelial cell proliferation, suggesting PAI-1 could trigger basal cell hyperplasia. A composite mid-esophageal BZH + PAI-1 score was the strongest predictor of altered compliance (P = .02, AUROC 0.89 (95% CI 0.80, 0.99). Conclusions: PAI-1 is significantly elevated in pediatric EoE and distinguishes altered compliance in children. PAI-1 may be a novel disease marker and therapeutic target.