Imaging the Effect of Experimental Stress on Small and Large Bowel Water During Fructose Absorption

Study Overview
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Brief Summary
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The investigators have been developing new, non-invasive magnetic resonance imaging (MRI) techniques to image the small bowel. Building on those studies the investigators want to study, in healthy volunteers, the effects of stress on the water content of the small bowel following ingestion of fructose. This is important because in Irritable Bowel Syndrome (IBS), there seems to be a strong association of stress and anxiety with the severity of the disease. Many IBS patients complain of food intolerances and recent studies have suggested that food with high content of fructose can worsen symptoms of IBS. The investigators will carry out a study in which the investigators will induce a moderate state of stress in healthy volunteers using an injection of corticotrophin release hormone, feed them a drink containing fructose and image their bowel at intervals using MRI. Improving our understanding of the effects of stress and fructose on small bowel physiology will help us to understand better some aspects of the symptoms such as bloating, altered bowel habit and abdominal discomfort, experienced by the IBS patients and to guide therapy. The investigators hypothesize that the effect of CRH will cause significant decrease in small bowel water content (SBWC) and a faster small bowel transit with increased malabsorption following consumption of fructose.

Detailed Description
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A single centre, randomized cross over study consisting a screening visit and 2 test days which will be approximately 7 days apart. The participants will receive 1g unlabelled lactose ureide in a glass of water 3 times a day on the day before the study day to induce the enzyme activity in the colonic bacteria. The participants (20 healthy volunteers) will have a baseline scan in a 1.5T MRI scanner before having a small intravenous needle inserted into their forearm. Following this procedure, the participant will have another scan before being given either a saline (0.9% NaCl) or 100microgram of CRH intravenous injection. 40g of fructose and 500mg of labeled C-13 lactose ureide dissolved in water with pure lime juice as flavorant made up to 500mL will be given to the participants. They will then have a serial scanning of the abdomen at 30-60 minutes interval for 5 hours post prandially. Salivary cortisol will be collected after every MRI scans. Participants will also be asked to blow into the hydrogen breath machine and to fill in symptom questionnaire following each MRI scans. Further breath collections for orocaecal transit time will be collected initially every 10 minutes for the first hour and 15 mins until the end of the study day. Mouthwash will be used before initial breath test collection. This procedure will be repeated again on the 2nd test day with either a saline or 100microgram of CRH.

Official Title
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Imaging the Effect of Experimental Stress on Small and Large Bowel Water During Fructose Absorption

Conditions
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Healthy

Intervention / Treatment
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* Drug: CRH
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Male or female healthy volunteers who are 18-60 years old Age ≥ 18 and ≤ 60 year at pre-study investigation. Body mass index (BMI) ≥ 18.0 and ≤ 30.0 kg/m2 Able to give voluntary informed consent to participate in the study Able to understand the requirements of the study including anonymous publication and free to cooperate with the study procedures Exclusion Criteria: Lactose intolerance Any history of serious acute or chronic illness especially gastrointestinal Any history of Raynaud's syndrome or impairment of circulation Any history of heart or lung disease Pregnancy or breastfeeding Smoking Unsuitable for MRI scanning (i.e. have metal implants or pacemaker) Regular medication interfering with gastrointestinal function, opiates or constipating drugs Substance abuse Have taken part in any other clinical study within the previous 3 months Previous gastrointestinal surgery Use of medication which interferes with study measurements or bowel motility (as judged by the study physician) such as antibiotics in the 2 weeks before pre-study examination or probiotics.

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 60 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Allocation: Randomized
Intervention Model: Crossover Assignment
Masking: Single


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Active Comparator: CRH<br>100 microgram bolus of Cortisol Releasing Hormone intravenous injection given at a 20 minutes prior to Fructose drink during one of the two visits. The placebo comparator will be 0.9% saline (1ml) bolus injection given intravenously at the same time point during one of the two visits | Drug: CRH<br> <br> * Other names: Proprietary name: CRH Ferring;|
| Placebo Comparator: Normal Saline (0.9%)<br>100 microgram bolus of Cortisol Releasing Hormone intravenous injection given at a 20 minutes prior to Fructose drink during one of the two visits. The placebo comparator will be 0.9% saline (1ml) bolus injection given intravenously at the same time point during one of the two visits | Drug: Placebo<br> <br> * Other names: Normal Saline (0.9%);|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Effect of CRF on area under curve volume versus time curve for small bowel water | Magnetic Resonance Imaging will be used to measure small bowel water at 30-60 minutes intervals for a total of 430 minutes | 430 minutes in total | 
| Effect of CRF on increase in volume of gas in colon at 255 minutes | Magnetic resonance imaging will be used to assess colonic gas at 255 minute time point | 15 minutes | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Gastric Emptying | Magnetic Resonance Imaging will be used to assess gastric emptying at 30-60 minute intervals for a total of 430 minutes | 430 minutes | 
| small bowel transit time using lactose C-13 ureide | Unlabelled lactose ureide 1g x3/day will be given 24 hours prior to study day. They will then be given 500mg 13C labelled lactose ureide on the study day and breath collections every 10 minutes initially for 1 hour and every 15 minute for subsequent hours | 430 minutes | 
| Ascending colon volume | Ascending colon volumes will be assessed using the Magnetic Resonance Imaging technique at 30-60 minute intervals | 430 minutes | 
| Volume of gas in colon | Volume of gas in colon will be assessed using the Magnetic Resonance Imaging technique at 30-60 minute intervals | 430 minutes | 
| salivary cortisol level versus small bowel water content | Saliva samples will be collected at the 30-60 minute intervals (as per the magnetic resonance imaging scans for small bowel water content) | 430 minutes | 
| Correlating symptom scores on the study day and Bristol Stool diary | Stool diary to be collected for a week | 7 days |