Randomised clinical study: Aspergillus niger-derived enzyme digests gluten in the stomach of healthy volunteers.

Abstract

SummaryBackground Aspergillus niger prolyl endoprotease (AN‐PEP) efficiently degrades gluten molecules into non‐immunogenic peptides in vitro.AimTo assess the efficacy of AN‐PEP on gluten degradation in a low and high calorie meal in healthy subjects.MethodsIn this randomised, double‐blind, placebo‐controlled, cross‐over study 12 healthy volunteers attended to four test days. A liquid low or high calorie meal (4 g gluten) with AN‐PEP or placebo was administered into the stomach. Via a triple‐lumen catheter gastric and duodenal aspirates were sampled, and polyethylene glycol (PEG)‐3350 was continuously infused. Acetaminophen in the meals tracked gastric emptying time. Gastric and duodenal samples were used to calculate 240‐min area under the curve (AUC 0–240 min) of ?‐gliadin concentrations. Absolute ?‐gliadin AUC 0–240 min was calculated using duodenal PEG‐3350 concentrations.Results AN‐PEP lowered α‐gliadin concentration AUC 0–240 min, compared to placebo, from low and high calorie meals in stomach (low: 35 vs. 389 μg × min/mL; high: 53 vs. 386 μg × min/mL; P < 0.001) and duodenum (low: 7 vs. 168 μg × min/mL; high: 4 vs. 32 μg × min/mL; P < 0.001) and absolute α‐gliadin AUC 0–240 min in the duodenum from low (2813 vs. 31 952 μg × min; P < 0.001) and high (2553 vs. 13 095 μg × min; P = 0.013) calorie meals. In the placebo group, the high compared to low calorie meal slowed gastric emptying and lowered the duodenal α‐gliadin concentration AUC 0–240 min (32 vs. 168 μg × min/mL; P = 0.001).ConclusionsAN‐PEP significantly enhanced gluten digestion in the stomach of healthy volunteers. Increasing caloric density prolonged gastric residence time of the meal. Since AN‐PEP already degraded most gluten from low calorie meals, no incremental effect was observed by increasing meal caloric density. ClinicalTrials.gov, Number: NCT01335503; www.trialregister.nl, Number: NTR2780.