In this study, we investigated the implication of oxygen-derived free radicals in reflux esophagitis of humans. For this purpose we assessed oxidative stress in distal esophageal biopsies of controls, patients with various grades of esophagitis, Barrett's esophagus with and without severe associated esophagitis and patients following Nissen fundoplication. The total amount of oxygen-derived free radicals was measured by chemiluminescence. Membrane damage caused by free radicals was assessed by analysis of lipid peroxidation. In addition, we measured esophageal mucosal tissue levels of the free radical scavenger superoxide dismutase.
Results: Chemiluminescence and lipid peroxidation increased with the grade of esophagitis and were highest in patients with Barrett's esophagus. Findings following Nissen fundoplication were similar to controls. Superoxide dismutase decreased as the grade of esophagitis increased being lowest in Barrett's patients with severe associated esophagitis. High superoxide dismutase levels were found in Barrett's mucosa with mild associated esophagitis.
Conclusions: Reflux esophagitis is mediated by free radicals. Barrett's is a severe form of oxidative damage. Antireflux surgery prevents oxidative damage of the esophageal mucosa. Superoxide dismutase is consumed by esophageal damage. In some patients with Barrett's, high superoxide dismutase levels of the esophageal mucosa may prevent severe esophagitis.