Characterization of ,-trehalase released in the intestinal lumen by the probiotic Saccharomyces boulardii

Objective. Trehalose intolerance due to ,-trehalase deficiency has scarcely been studied. The purpose of this study was to measure ,-trehalase activity in intestinal biopsy samples from 200 consecutive patients over a period of 6 months, and to characterize ,-trehalase released by the probiotic Saccharomyces boulardii (S. boulardii). Material and methods. Enzyme activities were measured in human and rat intestinal mucosal samples using the micromethod of Messer Dalqvist. ,-trehalase from S. boulardii was immunoprecipitated and Western blotted using an IgG purified antibody raised against a 23 amino acid peptide of ,-trehalase of S. cerevisiae. Results. Among 200 patients, most of whom complained of abdominal symptoms and diarrhoea, 18 (9%) had total ,-trehalase deficiency (0-12 U/g mucosa) and 39 had partial deficiency (3-12 U/g mucosa). Only 4 patients (2%) presented selective ,-trehalase deficiency with otherwise normal disaccharidases. Expressed per gram of powder, ,-trehalase from S. boulardii delivered in vitro an activity 175 times higher than that of human trehalase per gram of intestinal mucosa. Vmax (220.43 mol) and Km (5 mM) were close to that of the human enzyme, whereas Western blot revealed a signal of two subunits of 82 kDa. Finally, treatment of rats with S. boulardii resulted in increases in ,-trehalase activities of 25 to 45% (p0.01) in endoluminal fluid and intestinal mucosa compared with in controls. Conclusions. Our data suggest that ,-trehalase deficiency is more common than is believed and that oral administration of S. boulardii could be beneficial in patients with digestive symptoms caused by trehalose intolerance.