The Protease Inhibitor Darunavir Prevents Esophagitis and Impairments in Esophageal Barrier Function in a Mouse Model of GERD

Gastric reflux induces esophageal mucosal inflammation, partially mediated by the activation of hypoxia inducible factor 2α (HIF-2α). Pepsin, present in the refluxate, amplifies this inflammatory process and exacerbates tissue injury. Therefore, pepsin inhibition represents a promising strategy to reduce inflammation and preserve esophageal mucosal integrity. In this study, we evaluated the effects of darunavir, a protease inhibitor presently used to treat human immunodeficiency virus infection, in a gastroesophageal reflux disease (GERD) model in Swiss mice. Animals were anesthetized (ketamine and xylazine) and subjected to partial pyloric ligation and total ligation of the gastric fundus. Four experimental groups were established: sham (control), Sham+darunavir, GERD and GERD+darunavir. After three days, animals were euthanized, and the esophagus was collected to measure wet weight (edema), myeloperoxidase (MPO) activity, and keratinocyte-derived cytokines (KC). Western blot was performed for HIF-2α and tight junction proteins zonula occludens-1 (ZO-1) and occludin (OCLD). Histology with analysis of dilation of the intercellular space (DIS). Esophageal barrier function was assessed by transepithelial electrical resistance and fluorescein as an index of paracellular permeability. Darunavir’s anti-peptic activity was also demonstrated in vitro. GERD induced inflammation, with significant increases in edema, MPO, KC, DIS, histological changes and HIF-2α, and disrupted barrier function, reducing ZO-1 and OCLD levels. All these alterations were significantly reversed in darunavir-treated animals. These findings demonstrate that darunavir, a clinically available drug with anti-pepsin properties, inhibits GERD-induced inflammation and HIF-2α activation, preserving tight junction proteins and mucosal integrity. Thus, darunavir could be repurposed as a novel therapeutic option for GERD.