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

Abstract

Objective. Trehalose intolerance due to α,α-trehalase deficiency has scarcely been studied. The purpose of this study was to measure α,α-trehalase activity in intestinal biopsy samples from 200 consecutive patients over a period of 6 months, and to characterize α,α-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. α,α-trehalase from S. boulardii was immunoprecipitated and Western blotted using an IgG purified antibody raised against a 23 amino acid peptide of α,α-trehalase of S. cerevisiae. Results. Among 200 patients, most of whom complained of abdominal symptoms and diarrhoea, 18 (9%) had total α,α-trehalase deficiency (0–12 U/g mucosa) and 39 had partial deficiency (3–12 U/g mucosa). Only 4 patients (2%) presented selective α,α-trehalase deficiency with otherwise normal disaccharidases. Expressed per gram of powder, α,α-trehalase from S. boulardii delivered in vitro an activity 175 times higher than that of human trehalase per gram of intestinal mucosa. V_max (22±0.43 µmol) and K_m (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 α,α-trehalase activities of 25 to 45% (p<0.01) in endoluminal fluid and intestinal mucosa compared with in controls. Conclusions. Our data suggest that α,α-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.

• α,α-Trehalase
• human small intestine
• probiotic
• rat small intestine
• Saccharomyces boulardii