Title: Determination of urinary collection timeframes to enhance measurement of gastrointestinal (GI) site specific permeability in adults and children Authors
|Mcomber, Mark - BAYLOR COLLEGE MED|
Submitted to: Gastroenterology
Publication Type: Abstract Only
Publication Acceptance Date: February 1, 2008
Publication Date: April 1, 2008
Citation: McOmber, M.A., Shulman, R.J. 2008. Determination of urinary collection timeframes to enhance measurement of gastrointestinal (GI) site specific permeability in adults and children [abstract]. Gastroenterology. 134(Suppl.1):A-138. Technical Abstract: GI permeability testing using urinary recovery of orally administered mono- and disaccharides is used commonly. Combinations of sugars are used to measure permeability in different areas of the GI tract (i.e., site-specific permeability). However, human studies have not been published describing optimal collection timeframes for site specific permeability testing. This study was done to establish collection timeframes that would allow for simultaneous permeability comparisons at different gastrointestinal sites in both adults and children. Twelve adults (median age 34 yr; range 21-57) and 11 children (median age 11 yr; 5-17 yr old) were studied. Each subject drank 127.5 mL of a solution containing sucrose (10 g/dL), lactulose (5 g/dL), mannitol (1 g/dL), and sucralose (1 g/dL). Urine was collected over 24 hr. The first 12 hr of collection were performed while fasting, followed by another 12 hr of modified diet (i.e., avoiding artificial sweeteners). Sugar concentrations were measured using high-performance liquid chromatography. At each time point we calculated the ratios of the various sugars as well as the percent of the total amount of sugar ultimately recovered (% total recovered). Gastric Permeability: In adults median (range) Sucrose % total recovered at 30 min was 12% (4-36) and at 90 min was 33% (6-100). Corresponding values in children were 11% (4-34) and 31% (15-75). Small Intestinal Permeability: In adults Lactulose/Mannitol ratio peaked at a median of 11 hr (range 7-20) and Lactulose % total recovered was > 95% at a median of 14 hr (range 8-20). Corresponding values in children were 12 hr (range 9-20) and 15 hr (range 10-24). Colonic Permeability: In adults Sucralose/Lactulose ratio peaked at a median of 17 hr (range 2-26) and Sucralose % total recovered was > 95% at a median of 20 hr (range 10-24). Corresponding values in children were 17 hr (range 1-23) and 22 hr (range 14-24). 1) Urinary collection timeframes are comparable between adults and children; 2) Gastric permeability can be assessed in 90 min of collection but optimally longer; 3) Small intestinal permeability optimally requires 12 hr of collection; 4) Colonic permeability optimally requires 17 hr of collection; 5) The relative timing of L and SL urinary recovery (i.e., Lactulose preceding Sucralose) supports the evidence that they measure small intestinal and colonic permeability, respectively.