Title: Do patients with reflux disease have more gastroesophageal reflux episodes than healthy subjects? Acid and non-acid reflux during 24-Hr ambulatory pH-impedance recordings
Abstract: 1.7, reduced R of rabbit EE in lh by 43_+5% while exposure to acid-pepsin, 0.25 mg/ml, 0.5 mg/ml and 1.0 mg/ml reduced R by 61_+3%, 86_+3% and 89_+5%, respectively.After lh at pHs of 1.7, 2.0, 2.25, 2.5, and 3.0, acid-pepsin, 1.0 mg/ml, reduced R by 99_+0.1%,95-+3%, 94_+2%, 83_+5%, and 16_+5% respectively.Exposure to acid alone, pH 1.7, for 15 min decreased R by 18_+5% and on neutralization R returned to baseline compared to acid-pepsin, pH 1.7 + pepsin, 1 mg/ml, which reduced R by 52_+15% with little to no recovery after neutralization.Moreover, the decline in R with acid-pepsin was associated with an increase in mannitol flux in the absence of change on light microscopy.For primary cultured EE cells growing on glass coverslips, the % T.B. uptake was greater with acid-pepein than acid alone at pH 2 and 1 but not pH 3; but this difference in % T.B. uptake was abolished if EE cells were exposed to acid or acid plus pepsin while in suspension.CONCLUSIONS: Pepsin damages the EE at concentrations >0.15 mg/ml and at acidic pH values of < 3. Pepsin enhances the rate and degree of injury to EE at acid pH by irreversibly damaging the intercellular junctional complex so that it increases the rate of acid access to the cell's more acid permeable basolateral membranes.