Clinical Trial: L-cysteine Prevents Stomach Exposure to Carcinogenic Acetaldehyde

Study Status: Completed
Recruit Status: Completed
Study Type: Interventional

Official Title: Slow-release L-cysteine Capsule Prevents Carcinogenic Gastric Acetaldehyde Exposure in Helicobacter-associated Atrophic Gastritis

Brief Summary:

Atrophic gastritis with hypochlorhydric milieu is a risk factor for gastric cancer. Microbes colonizing the acid-free stomach oxidize ethanol into acetaldehyde, a group 1 carcinogen. The aim is to assess gastric production of acetaldehyde and its inert condensation product, non-toxic 4-methyltiazolidine-2-carboxylic acid (MTCA), after alcohol intake under treatment with slow-release L-cysteine or placebo.

Patients with biopsy-confirmed atrophic gastritis, low serum pepsinogen and high gastrin-17 are studied. On separate days, patients will be randomly assigned to receive 200 mg slow-release L-cysteine or placebo, then have intragastric instillation of 15% (0.3 g/kg) ethanol. After intake, gastric concentrations of acetaldehyde, ethanol, L-cysteine and MTCA are analysed for 4 hours.

Expected results show mitigated exposure of the gastric mucosa to acetaldehyde.


Detailed Summary:

Gastric infection with Helicobacter pylori induces chronic active gastritis which over the years develop atrophic gastritis with a hypochlorhydric milieu which is a risk factor for gastric cancer. Microbes colonizing acid-free stomach oxidize ethanol into acetaldehyde, considered a group 1 carcinogen.

The aim of the study is to assess the gastric production of acetaldehyde and its inert condensation product, non-toxic 4-methyltiazolidine-2-carboxylic acid (MTCA), after alcohol intake under treatment with slow-release L-cysteine. Identical placebo tablets will be used for comparison.

Patients with biopsy-confirmed atrophic gastritis, low serum pepsinogen and high gastrin-17 will be studied with case-control design. All subjects will be their own control. On separate days, patients are randomly assigned to receive 200 mg slow-release L-cysteine or placebo, then have intragastric instillation of 15% (0.3 g/kg) ethanol (corresponding to two glasses of wine). After intake, gastric sampling of fluid for a period of four hours is done and concentrations of acetaldehyde, ethanol, L-cysteine and MTCA are analysed.

L-cysteine is expected to decrease gastric acetaldehyde concentrations and increase the MTCA level. Gastric L-cysteine and MTCA concentrations are expected to be maintained over the study period. With placebo, acetaldehyde is expected to be elevated along with ethanol concentrations.

Based on these assumptions slow-release L-cysteine binds acetaldehyde to form inactive MTCA, which remains in gastric juice resulting in reduced local exposure of the gastric mucosa to carcinogenic acetaldehyde.


Sponsor: Per Hellström

Current Primary Outcome: Acetaldehyde concentrations in the stomach [ Time Frame: 4 hours ]

Binding of acetaldehyde to L-cysteine


Original Primary Outcome: Same as current

Current Secondary Outcome: 4-methyltiazolidine-2-carboxylic acid concentration in the stomach [ Time Frame: 4 hours ]

Production of inert 4-methyltiazolidine-2-carboxylic acid after binding to L-cysteine


Original Secondary Outcome: Same as current

Information By: Uppsala University

Dates:
Date Received: August 13, 2015
Date Started: December 2012
Date Completion:
Last Updated: January 21, 2016
Last Verified: January 2016