Studies on the Relationship between Esophageal Acid Exposure, Mucosal Lesions and Heartburn Using an Acid Exposure Sensor

Abstract

Background: In vitro studies of a recently developed acid exposure sensor show that the sensor response (SR) to acid < pH 4 is linearly determined by the duration and degree of acidity. The aim was to determine whether SR correlates with the severity of acid-induced esophageal mucosal lesions and acid-induced heartburn. Methods: HCl pH 1.5 or saline was infused into the feline esophagus for 5-20 min. Simultaneously, sensor measurements were performed below the infusion port. The histological damage was scored by an independent pathologist. In 15 normal subjects, HCl pH 1 was infused into the esophagus and the severity of the heartburn (0-5) was scored at 5-min intervals. In 10 subjects who experienced heartburn during acid perfusion, initial perfusion with HCl was repeated during heartburn induction time minus 5 min, followed by perfusion with the subject's own gastric juice, titrated to pH 2; heartburn severity was again scored at 5-min intervals. Acid exposure sensors positioned below the infusion port were removed at heartburn scores 1, 2 and 3. Results: A good correlation was found between SR and the histological score for mucosal damage in the cat esophagus ( r = 0.64, P < 0.005). There was a good relation between heartburn severity score and acid exposure time ( r = 0.84, P < 0.001), and a significant but weaker relation between heartburn severity and SR. Conclusion: In cats, there is a good relation between the severity of acid-induced esophageal mucosal lesions and SR. In men, there is a significant correlation between the severity of acid-induced heartburn and the simultaneously measured SR. Therefore, SR measurement has the potential of yielding clinically relevant information in the investigation of GERD.