Mo1257 Crosstalk Between Carbon Monoxide (CO) Released From Tricarbonyldichlororuthenium (II) Dimer (Corm-2) and Endogenous Nitric Oxide (NO) in Gastroprotection Against Stress-Induced Gastric Lesions

of injury was based on H&E histologic sections, and immunohistochemistry for SOX9 (progenitor) and CK7 was performed.Phospho-histone H3 (PHH3) mitotic staining was used to compare proliferation in the ESMG-containing proximal area of the esophagus to the ESMG-lacking area of the distal esophagus.Results: The RFA method provided consistent and reproducible mucosal injury: inflammatory response began 18 hours post-RFA, and peaked at 72 hours.Epithelial restitution began at 5 days with more complete repair at 7 days.The ductular phenotype was increased in the ESMGs at 7 days (5-fold increase).There was a 2-fold increase in CK7 positive cells in ESMGs after injury at 5 and 7 days in proximal esophagus.SOX9, which is not expressed in normal porcine squamous epithelium, was expressed in neosquamous epithelium at 5 and 7 days.As expected, based on PHH3 staining, proliferation was evident in basal epithelial squamous cells as well as in ESMGs and ducts.Total positive PHH3 nuclei were increased 5-fold at 5 and 7 days regardless of esophageal region.Conclusions: In accordance with our hypothesis, increased CK7 expression in ESMGs indicates a ductular response post-injury and is accompanied by increased proliferation as well as increased expression of the progenitor marker SOX9.The similarities between the porcine ESMGs after injury and human ADM support the use of this model for additional mechanistic study of esophageal epithelial repair. Mo1254Superior Healing Efficacy of a New Potassium-Competitive Acid Blocker Vonoprazan (TK-438) Than That of Proton Pump Inhibitors for Post Gastric Endoscopic Submucosal Dissection Artificial Ulcers