Bile acids do not modify the effects of pepsin on the fine structure of human oesophageal epithelium.

Oesophageal mucosal specimens (n = 250) were taken from 25 normal subjects (14 females, 11 males; median age 52 years; range 19-63 years) and incubated in physiological saline, pepsin and bile acid solutions to determine whether conjugated bile acids modify the epithelial cytotoxic action of pepsin. Short (5 min) and long (22 min) incubations were carried out and the results were assessed by transmission electron microscopy. Six different parameters of epithelial damage were scored (0-4) by a single 'blinded' pathologist for each of four epithelial layers. The scores after incubation in saline (pH 7 and titrated to pH 2 with HCl) were not different from those of the controls (P = 0.35). Both pepsin and bile acids (pH 2) caused more damage than saline at pH 2 (P less than 0.001) which was similar for the two substances (P = 0.136). Conjugated bile acids in combination with pepsin (pH 2) did not alter the overall extent or pattern of damage caused by pepsin alone (pH 2); P = 0.142). Conjugated bile acids, in concentrations commonly encountered during gastro-oesophageal reflux, did not appear to modify the cytopathic effects of pepsin on oesophageal mucosal cells in vitro. Conjugated bile acids may not be important in the pathogenesis of oesophagitis in patients with acid/peptic gastro-oesophageal reflux.