Performance of 13C Mannitol for in Vivo Measurement of Small Intestinal Permeability

An impaired intestinal permeability is implicated in the pathophysiology of a number of disorders such as celiac disease, environmental enteropathy, inflammatory bowel disease, obesity, and HIV. Current measurements of intestinal permeability rely on urinary excretion of naturally available, orally ingested, non-absorbable sugars (e.g. lactulose, mannitol). However, dietary intake of these sugars limits interpretation from these assays.

Subjects will have an esophagogastroduodenoscopy (EGD) with biopsies and provide a baseline urine sample. They will be asked to ingest 3 saccharides (12C mannitol 100 mg,13C mannitol 100 mg and lactulose 1 g) in 250 ml of water. Urine samples will be obtained every 30 min. in the Clinical Research and Trials Unit (CRTU) for 0-2 hours. Subjects will collect 2-8 hour sample in provided container. Another container will be provided to collect the 8-24 hour urine which will be returned the following morning. Subjects will undergo an Indomethacin challenge intervention. They will be instructed to take three 25 mg capsules 8 hours before their next visit (just before fasting). They will take 3 additional 25 mg capsules 30 min. before the repeat in vivo permeability testing. Repeat EGD with duodenal biopsies will be done. Long term follow-up will be done within 4-6 weeks of previous testing, where subjects will once again be asked to complete the in vivo permeability testing.

Healthy Volunteers

Inclusion criteria

• Age (yr) 18 to 65
• No abdominal surgery (except appendectomy and cholecystectomy, others may be considered)

Exclusion criteria

• History of irritable bowel syndrome (IBS), inflammatory bowel disease (IBD) (Crohn's disease or ulcerative colitis), microscopic colitis or celiac disease.
• Use of tobacco products within the past 6 months (since nicotine may affect intestinal permeability)
• Use of nonsteroidal anti-inflammatory drugs (NSAIDs) or aspirin within seven days of first permeability test (as NSAIDs affect intestinal permeability) and second permeability test (except those administered for the study)
• Use of oral corticosteroids within the previous 6 weeks
• Ingestion of artificial sweeteners such as Splenda® (sucralose), NutraSweet® (aspartame), lactulose or mannitol within two (2) days of each permeability test and endoscopy procedure date, e.g., foods to be avoided are sugarless gums or mints and diet soda
• Ingestion of any prescription, over the counter, or herbal medications which can affect gastrointestinal transit within 7 days each permeability test and endoscopy procedure date. This includes drugs such as serotonin (5-HT) agents, narcotics, anticholinergics, anti-nausea medications, any medications for diarrhea or constipation.
• Antibiotics within 7 days each permeability test and endoscopy procedure date
• Bleeding disorders or medications that increase risk of bleeding from mucosal biopsies.
• Score > 8 for anxiety or depression on Hospital Anxiety and Depression scale.
• Pregnancy