Toxic bile acids in gastro-oesophageal reflux disease: influence of gastric acidity

Background-Bile acid toxicity has been shown in the gastric, colonic, and h epatic tissues; the effect on oesophageal mucosa is less well known. Aims-To determine the spectrum of bile acids refluxing in patients with gas trooesophageal reflux disease and its relation to oesophageal pH using a ne w technique of combined oesophageal aspiration and pH monitoring. Methods-Ten asymptomatic subjects and 30 patients with symptoms of gastrooe sophageal reflux disease (minimal mucosal injury, erosive oesophagitis (gra de 2 or 3 Savary-Miller), Barrett's oesophagus/stricture; n=10 in each grou p) underwent 15 hour continuous oesophageal aspiration with simultaneous pH monitoring. Bile acid assay of the oesophageal samples was performed using modified high performance liquid chromatography. Results-The peak bile acid concentration and DeMeester acid scores were sig nificantly higher in the patients with oesophagitis (median bile acid conce ntration 124 mu mol/l; acid score 20.2) and Barrett's oesophagus/stricture (181 mu mol/l; 43.3) than patients with minimal injury (14 mu mol/l; 12.5) or controls (0 mu mol/l; 11.1). The predominant bile acids detected were ch olic, taurocholic, and glycocholic acids but there was a significantly grea ter proportion of secondary bile acids, deoxycholic and taurodeoxycholic ac ids, in patients with erosive oesophagitis and Barrett's oesophagus/strictu re. Although bile acid reflux episodes occurred at variable pH, a temporal relation existed between reflux of taurine conjugates and oesophageal acid exposure (r=0.58, p=0.009). Conclusion-Toxic secondary bile acid fractions have been detected in patien ts with extensive mucosal damage. Mixed reflux is more harmful than acid re flux alone with possible toxic synergism existing between the taurine conju gates and acid.