Clinical Trial: Comparison of the Colonic Metabolism in Patients With Lactose Intolerance and Healthy Controls

Study Status: Completed
Recruit Status: Completed
Study Type: Observational

Official Title: Comparison of the Colonic Metabolism in Patients With Lactose Intolerance and Healthy Controls

Brief Summary:

Most people are born with the ability to digest lactose, a dissacharide consisting of β-D-glucose and β-D-galactose, because of the presence of lactase at the brush border of the small intestine. In about 75% of the world population the activity of this enzyme decreases after weaning (primary hypolactasia or lactase-nonpersistence), resulting in incomplete digestion of lactose and lactose malabsorption in adulthood (1). Secondary forms of lactose malabsorption may be due to inflammation or functional loss of the intestinal mucosa such as celiac disease, infectious enteritis or Crohn's disease. Very rarely, lactase deficiency is congenital due to an autosomal recessive genetic disorder, preventing lactase expression from birth (2). Whereas some people with lactose malabsorption are asymptomatic, most lactose-nonpersisters experience symptoms like abdominal pain, bloating, excess flatulence or diarrhea. Lactose intolerance refers to the syndrome of having one or more symptoms after consumption of lactose-containing food (3). At present, the origin of the symptoms of lactose-intolerance is not well understood.

Several studies have indicated a poor correlation between lactose maldigestion and symptoms of lactose intolerance (4). In a study by Vonk et al. (2003), lactose intolerant subjects with severe symptoms (diarrhea) and intolerant subjects with only mild symptoms (without diarrhea) did not differ in degree of lactose digestion in the small intestine indicating a similar lactase activity and leading them to the hypothesis of a "colon resistence factor" (5). It was suggested that the colonic processing of maldigested lactose may play a role in the symptoms experienced by lactose intolerant patients. When lactose is malabsorbed and enters the colon, it is rapidly fermented by the resident microbiota into a variety of metabolites including lactate, format

Detailed Summary: In this study we will compare colonic fermentation and parameters of gut health (fecal water cytotoxicity) between patients who are lactose intolerant, patients who have lactose malabsorption and healthy subjects.
Sponsor: Katholieke Universiteit Leuven

Current Primary Outcome: fecal water genotoxicity [ Time Frame: 1 day ]

Fecal water, prepared by ultracentrifugation of fecal samples, will be incubated with HT-29 cells, a colonic adenocarcinoma cell line. Fecal water genotoxicity will be assessed using the Comet Assay, a sensitive method to detect DNA damage at the level of the individual eukaryotic cell. During the Comet Assay, the cells undergo electrophoresis causing movement of the damaged DNA out of the nucleus. The amount of DNA damage will be determined by measuring the extent the DNA has moved out of the nucleus, using fluorescent microcropy and dedicated software.


Original Primary Outcome: Same as current

Current Secondary Outcome: fecal water cytotoxicity [ Time Frame: 1 day ]

Fecal water cytotoxicity will be measured using the WST-1 assay, a colorimetric test based on the conversion of the tetrazolium salt WST-1 by cellular mitochondrial dehydrogenases present in viable cells. The dilution of fecal water at which 50% of the cells survive will be determined. The higher the dilution, the more cytotoxic the sample is.


Original Secondary Outcome: Same as current

Information By: Katholieke Universiteit Leuven

Dates:
Date Received: June 18, 2014
Date Started: June 2014
Date Completion:
Last Updated: July 28, 2015
Last Verified: July 2015