Ingestion of saccharides (mannitol (regular, 12C) 100 mg, lactulose 1 g and (non-radioactive) 13C labeled mannitol, 100 mg and sucralose, 50 mg) in 250ml of water Esophagogastroduodenoscopy Flexible sigmoidoscopy

Esophagogastroduodenoscopy: Duodenal biopsies will be collected from Healthy Volunteers.

Flexible sigmoidoscopy: Colonic biopsies will be collected from Healthy Volunteers.

Ingestion of saccharides (mannitol (regular, 12C) 100 mg, lactulose 1 g and (non-radioactive) 13C labeled mannitol, 100 mg and sucralose, 50 mg) in 250ml of water Esophagogastroduodenoscopy Flexible sigmoidoscopy

Esophagogastroduodenoscopy: Duodenal biopsies will be collected from IBS - C cases.

Flexible sigmoidoscopy: Colonic biopsies will be collected from IBS - C cases.

Four biopsies from duodenum from the Healthy Volunteers were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured.Average TMR and Isc across 3-4 biopsies/subject were calculated.Paracellular flux across biopsies was measured using 4 kDa FITC-Dextran administered on the mucosal side (1 mg/mL chamber concentration). Cumulative flux at the end of three hours and rate of flux was calculated for FITC-Dextran.

Four biopsies from duodenum from the IBS - C cases were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured.Average TMR and Isc across 3-4 biopsies/subject were calculated.Paracellular flux across biopsies was measured using 4 kDa FITC-Dextran administered on the mucosal side (1 mg/mL chamber concentration). Cumulative flux at the end of three hours and rate of flux was calculated for FITC-Dextran

Four biopsies from each site from the Healthy Volunteers were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured.Average TMR and Isc across 3-4 biopsies/subject were calculated.Paracellular flux across biopsies was measured using 4 kDa FITC-Dextran administered on the mucosal side (1 mg/mL chamber concentration). Cumulative flux at the end of three hours and rate of flux was calculated for FITC-Dextran.

Four biopsies from each site from the IBS - C cases were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured.Average TMR and Isc across 3-4 biopsies/subject were calculated.Paracellular flux across biopsies was measured using 4 kDa FITC-Dextran administered on the mucosal side (1 mg/mL chamber concentration). Cumulative flux at the end of three hours and rate of flux was calculated for FITC-Dextran

Four biopsies from each site from the Healthy Volunteers were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured.Average TMR and Isc across 3-4 biopsies/subject were calculated.Paracellular flux across biopsies was measured using 4 kDa FITC-Dextran administered on the mucosal side (1 mg/mL chamber concentration). Cumulative flux at the end of three hours and rate of flux was calculated for FITC-Dextran.

Four biopsies from each site from the IBS - C cases were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured.Average TMR and Isc across 3-4 biopsies/subject were calculated.Paracellular flux across biopsies was measured using 4 kDa FITC-Dextran administered on the mucosal side (1 mg/mL chamber concentration). Cumulative flux at the end of three hours and rate of flux was calculated for FITC-Dextran

Four biopsies from colon from the Healthy Volunteers were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured.Average TMR and Isc across 3-4 biopsies/subject were calculated.Paracellular flux across biopsies was measured using 4 kDa FITC-Dextran administered on the mucosal side (1 mg/mL chamber concentration). Cumulative flux at the end of three hours and rate of flux was calculated for FITC-Dextran.

Four biopsies from colon from the IBS - C cases were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured.Average TMR and Isc across 3-4 biopsies/subject were calculated.Paracellular flux across biopsies was measured using 4 kDa FITC-Dextran administered on the mucosal side (1 mg/mL chamber concentration). Cumulative flux at the end of three hours and rate of flux was calculated for FITC-Dextran

Four biopsies from colon from the Healthy Volunteers were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured.Average TMR and Isc across 3-4 biopsies/subject were calculated.Paracellular flux across biopsies was measured using 4 kDa FITC-Dextran administered on the mucosal side (1 mg/mL chamber concentration). Cumulative flux at the end of three hours and rate of flux was calculated for FITC-Dextran.

Four biopsies from colon from the IBS - C cases were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured.Average TMR and Isc across 3-4 biopsies/subject were calculated.Paracellular flux across biopsies was measured using 4 kDa FITC-Dextran administered on the mucosal side (1 mg/mL chamber concentration). Cumulative flux at the end of three hours and rate of flux was calculated for FITC-Dextran

Four biopsies from colon from the Healthy Volunteers were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured.Average TMR and Isc across 3-4 biopsies/subject were calculated.Paracellular flux across biopsies was measured using 4 kDa FITC-Dextran administered on the mucosal side (1 mg/mL chamber concentration). Cumulative flux at the end of three hours and rate of flux was calculated for FITC-Dextran.

Four biopsies from colon from the IBS - C cases were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured.Average TMR and Isc across 3-4 biopsies/subject were calculated.Paracellular flux across biopsies was measured using 4 kDa FITC-Dextran administered on the mucosal side (1 mg/mL chamber concentration). Cumulative flux at the end of three hours and rate of flux was calculated for FITC-Dextran

Four biopsies from duodenum from the Healthy Volunteers were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured. Average TMR and Isc across 3-4 biopsies/subject were calculated. Transcellular transport was studied by using translocation of the fluorescently labeled E. coli K-12 Bio-Particles was measured using a 107 CFU/mL chamber concentration on the mucosal side. Cumulative flux at the end of three hours and rate of flux was calculated for E. coli K-12 Bio-Particles.

Four biopsies from duodenum from the IBS - C cases were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured. Average TMR and Isc across 3-4 biopsies/subject were calculated. Transcellular transport was studied by using translocation of the fluorescently labeled E. coli K-12 Bio-Particles was measured using a 107 CFU/mL chamber concentration on the mucosal side. Cumulative flux at the end of three hours and rate of flux was calculated for E. coli K-12 Bio-Particles.

Four biopsies from duodenum from the Healthy Volunteers were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured. Average TMR and Isc across 3-4 biopsies/subject were calculated. Transcellular transport was studied by using translocation of the fluorescently labeled E. coli K-12 Bio-Particles was measured using a 107 CFU/mL chamber concentration on the mucosal side. Cumulative flux at the end of three hours and rate of flux was calculated for E. coli K-12 Bio-Particles.

Four biopsies from duodenum from the IBS - C cases were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured. Average TMR and Isc across 3-4 biopsies/subject were calculated. Transcellular transport was studied by using translocation of the fluorescently labeled E. coli K-12 Bio-Particles was measured using a 107 CFU/mL chamber concentration on the mucosal side. Cumulative flux at the end of three hours and rate of flux was calculated for E. coli K-12 Bio-Particles.

Four biopsies from colon from the Healthy Volunteers were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured. Average TMR and Isc across 3-4 biopsies/subject were calculated. Transcellular transport was studied by using translocation of the fluorescently labeled E. coli K-12 Bio-Particles was measured using a 107 CFU/mL chamber concentration on the mucosal side. Cumulative flux at the end of three hours and rate of flux was calculated for E. coli K-12 Bio-Particles.

Four biopsies from colon from the IBS - C cases were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured. Average TMR and Isc across 3-4 biopsies/subject were calculated. Transcellular transport was studied by using translocation of the fluorescently labeled E. coli K-12 Bio-Particles was measured using a 107 CFU/mL chamber concentration on the mucosal side. Cumulative flux at the end of three hours and rate of flux was calculated for E. coli K-12 Bio-Particles.

Four biopsies from colon from the Healthy Volunteers were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured. Average TMR and Isc across 3-4 biopsies/subject were calculated. Transcellular transport was studied by using translocation of the fluorescently labeled E. coli K-12 Bio-Particles was measured using a 107 CFU/mL chamber concentration on the mucosal side. Cumulative flux at the end of three hours and rate of flux was calculated for E. coli K-12 Bio-Particles.

Four biopsies from colon from the IBS - C cases were mounted in 4 mL Ussing chambers (Physiologic Instruments, San Diego, CA, USA) exposing 0.031 sq.cm area, within 45 min of collection. Chambers were filled with Krebs with 10 mM mannitol (mucosal side) and Krebs with 10 mM glucose (submucosal side).Baseline transmucosal resistance (TMR) and short circuit current (Isc) of each tissue was measured. Average TMR and Isc across 3-4 biopsies/subject were calculated. Transcellular transport was studied by using translocation of the fluorescently labeled E. coli K-12 Bio-Particles was measured using a 107 CFU/mL chamber concentration on the mucosal side. Cumulative flux at the end of three hours and rate of flux was calculated for E. coli K-12 Bio-Particles.

Volunteers fasted for eight hours and underwent sedated esophagogastroduodenoscopy. Duodenal impedance measurements were performed using a endoscopically passed catheter that measures electrical impedance of the duodenal epithelium by mucosal contact under direct visualization. A 2 mm diameter catheter was used with two 360° circumferential sensors placed at a separation of 2mm with the end of the distal ring being 1mm away from the catheter tip. The electrodes were connected to an impedance voltage transducer via thin wires, which ran the length of the catheter traversing through the working channel of the upper endoscope. The voltage generated by the transducer was limited to produce 10µA current at a frequency of 2 kHz. Impedance was measured every 90° in duodenal circumference with a decompressed lumen after suctioning of all fluid from the lumen. The catheter was embedded in the mucosa parallel to the two sensors and measurements were taken from a steady baseline for >10s.

IBS - C cases fasted for eight hours and underwent sedated esophagogastroduodenoscopy. Duodenal impedance measurements were performed using a endoscopically passed catheter that measures electrical impedance of the duodenal epithelium by mucosal contact under direct visualization. A 2 mm diameter catheter was used with two 360° circumferential sensors placed at a separation of 2mm with the end of the distal ring being 1mm away from the catheter tip. The electrodes were connected to an impedance voltage transducer via thin wires, which ran the length of the catheter traversing through the working channel of the upper endoscope. The voltage generated by the transducer was limited to produce 10µA current at a frequency of 2 kHz. Impedance was measured every 90° in duodenal circumference with a decompressed lumen after suctioning of all fluid from the lumen. The catheter was embedded in the mucosa parallel to the two sensors and measurements were taken from a steady baseline for >10s.

Fasting, EDTA anti-coagulated, whole blood was collected from Healthy Volunteers. Samples were analyzed using an EAA kit (Spectral Diagnostic Inc, Toronto, Ontario, Canada) that utilizes a monoclonal IgM antibody specific for gram-negative bacterial lipopolysaccharide (LPS). Samples were tested in duplicate within one hour of collection using a Berthold SmartLine luminometer (photon-counting). The endotoxin activity level was calculated as follows: chemiluminescence (test sample-negative control)/chemiluminescence (positive-negative control). Average values for each participant were expressed as absolute units.

Fasting, EDTA anti-coagulated, whole blood was collected from IBS - C cases. Samples were analyzed using an EAA kit (Spectral Diagnostic Inc, Toronto, Ontario, Canada) that utilizes a monoclonal IgM antibody specific for gram-negative bacterial lipopolysaccharide (LPS). Samples were tested in duplicate within one hour of collection using a Berthold SmartLine luminometer (photon-counting). The endotoxin activity level was calculated as follows: chemiluminescence (test sample-negative control)/chemiluminescence (positive-negative control). Average values for each participant were expressed as absolute units.