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Trial registered on ANZCTR


Registration number
ACTRN12613000758707
Ethics application status
Approved
Date submitted
4/07/2013
Date registered
8/07/2013
Date last updated
8/07/2013
Type of registration
Retrospectively registered

Titles & IDs
Public title
Evaluation of sweet taste receptors, glucose transporters, glucose absorption and gastrointestinal hormones in obesity and after bariatric surgery.
Scientific title
Evaluation of sweet taste receptors, glucose transporters, glucose absorption and gastrointestinal hormones in obesity and after bariatric surgery.
Secondary ID [1] 282775 0
none
Universal Trial Number (UTN)
Trial acronym
STR study
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Obesity 289527 0
Laparoscopic adjustable gastric banding (LAGB) and Roux-en-Y Gastric Bypass (RYGB) surgery 289528 0
Diabetes Mellitus 289529 0
Condition category
Condition code
Diet and Nutrition 289853 289853 0 0
Obesity
Surgery 289854 289854 0 0
Other surgery
Oral and Gastrointestinal 289855 289855 0 0
Normal oral and gastrointestinal development and function

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Arm 1 - Patients who have previously had bariatric surgery
After inserting a thin endoscope through the nose to the duodenum, 3 biopsies will be taken. A glucose solution (30g glucose and 3g #-OMG) will then be infused into the duodenum for 30 minutes. We will collect another 3 biopsies at the end of the infusion. After 30 minutes of glucose infusion, the endoscope will be removed. Blood samples will be taken at various timepoints throughout the study to measure levels of glucose, 3-OMG, and hormones produced in response to glucose.
Arm 2
Obese patients will undergo the same procedure as those in Arm 1, but will have the procedure done twice, once before and once after a two week Optifast diet (Taking one satchet of Optifast dietary supplemement (different flavoured shakes) 3x daily for two weeks) Apart from two cups of low starch vegetables daily and calorie free fluids, this will be all they will consume for the two week period. Optifast products are classified as very low calorie diets (also known as VLEDs or very low energy diets) have been shown to be very effective in the treatment of obesity, with weekly weight losses averaging approximately 2.0kg in the first 4-6 weeks, providing greater initial weight loss than other forms of calorie restriction.

Each 54g satchet of Optifast dietary supplement contains:
Skimmed Milk Powder, Calcium Caseinate, Sodium Caseinate, Inulin, Maltodextrin (Corn), Vegetable Oils (Canola, Sunflower), Fructose, Sugar, Coffee Extract, Minerals (Potassium Citrate, Magnesium Carbonate, Potassium Phosphate, Sodium Chloride, Ferric Pyrophosphate, Zinc Sulphate, Copper Gluconate,Tricalcium Phosphate, Manganese Sulphate, Sodium Fluoride, Chromium Chloride, Sodium Selenite, Sodium Molybdate, Potassium Iodide), Glucose Syrup (Corn, Wheat Or Potato), Medium Chain Triglycerides, Flavour, Fish Oil, Corn Starch, Vegetable Gum (414), Sweeteners (Aspartame, Acesulfame Potassium), Emulsifiers (Soy Lecithin, 472c, 471), Vitamins (Ascorbic Acid, Vitamin E Acetate, Nicotinamide, Calcium Pantothenate, Pyridoxine Hydrochloride, Thiamin Hydrochloride, Riboflavin, Vitamin A Acetate, Folic Acid, Biotin, Phytonadione, Cholecalciferol, Cyanocobalamin), Antioxidants (304, 307). Contains Milk, Soy, Wheat and Fish. Contains Phenylalanine. Made on equipment that also processes products containing Egg and Celery.

To Monitor adherance to the diet a weekly phone call is made to see how they are progressing with their diet, and also weight is measured before and after the two weeks to monitor weight loss.

Arm 3/Healthy control
In the healthy volunteers, the same procedure is performaed as the other arms. After inserting a thin endoscope through the nose to the duodenum, 3 biopsies will be taken. A glucose solution (30g glucose and 3g #-OMG) will then be infused into the duodenum for 30 minutes. We will collect another 3 biopsies at the end of the infusion. After 30 minutes of glucose infusion, the endoscope will be removed. Blood samples will be taken at various timepoints throughout the study to measure levels of glucose, 3-OMG, and hormones produced in response to glucose.
Intervention code [1] 287444 0
Treatment: Other
Intervention code [2] 287445 0
Lifestyle
Comparator / control treatment
Healthy control
In the healthy volunteers, the same procedure is performaed as the other arms. After inserting a thin endoscope through the nose to the duodenum, 3 biopsies will be taken. A glucose solution (30g glucose and 3g #-OMG) will then be infused into the duodenum for 30 minutes. We will collect another 3 biopsies at the end of the infusion. After 30 minutes of glucose infusion, the endoscope will be removed. Blood samples will be taken at various timepoints throughout the study to measure levels of glucose, 3-OMG, and hormones produced in response to glucose.
Control group
Active

Outcomes
Primary outcome [1] 289916 0
Small intestinal sweet taste receptors (T1R2, T1R3, Gagust and TRPM5) during fasting and following 30 minutes of glucose stimulation measured by biopsies taken during endoscopy
Timepoint [1] 289916 0
3 biopsies taken at t=0min and 30min
Primary outcome [2] 289917 0
Small intestinal carbohydrate transporters (SGLT1 and GLUT2) during fasting and following 30 minute of glucose stimulation as measured by biopsies taken at various timpoints during endoscopy.
Timepoint [2] 289917 0
3 biopsies taken at t=0min and 30min
Primary outcome [3] 289918 0
Glucose absorption (measured using 3-OMG concentrations (from blood sample) area under curves 0-240 min)
Timepoint [3] 289918 0
blood samples taken at t = 0, 15, 30, 45, 60, 75, 90, 105, 120, 150, 180, 210, and 240 mins.
Secondary outcome [1] 303567 0
The relationships between sweet taste receptors, carbohydrate transporters, glucose absorption and release of incretin hormones (GLP-1, PYY, CCK and insulin).
Timepoint [1] 303567 0
This is analysed after all data collection is complete

Eligibility
Key inclusion criteria
Obese patients - BMI > 40kg/m2
Bariatric patients - RYGB or LAGB surgery > 12 months ago
Healthy volunteers - BMI < 40kg/m2
Minimum age
18 Years
Maximum age
70 Years
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
History of severe respiratory, cardiovascular, hepatic and/or renal disease, chronic alcohol abuse or epilepsy (excluded by history)
Medication that may influence gastrointestinal function
History of surgery to the gastrointestinal tract apart from the RYGB or LAGB
Female patients not using appropriate contraceptive method (ie oral contraceptive pill, diaphragm, Depo-Provera hormonal contraceptive injection, intrauterine device, Norplant method)
Pregnant and/or breastfeeding mothers

Study design
Purpose of the study
Educational / counselling / training
Allocation to intervention
Non-randomised trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
Masking / blinding
Who is / are masked / blinded?



Intervention assignment
Other design features
Phase
Not Applicable
Type of endpoint(s)
Pharmacokinetics / pharmacodynamics
Statistical methods / analysis

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
Date of last participant enrolment
Anticipated
Actual
Date of last data collection
Anticipated
Actual
Sample size
Target
Accrual to date
Final
Recruitment in Australia
Recruitment state(s)
SA
Recruitment hospital [1] 1195 0
The Royal Adelaide Hospital - Adelaide

Funding & Sponsors
Funding source category [1] 287544 0
Hospital
Name [1] 287544 0
Department of Gastroenterology and Hepatology, Royal Adelaide Hospital
Address [1] 287544 0
Department of Gastroenterology and Hepatology,
Level 7 Q7 North Wing
Royal Adelaide Hospital
North Terrace
Adelaide SA 5000
Country [1] 287544 0
Australia
Primary sponsor type
Individual
Name
Dr. Nam Nguyen
Address
Department of Gastroenterology and Hepatology
Level 7 Q7 North Wing
Royal Adelaide Hospital
North Terrace
Adelaide SA 5000
Country
Australia
Secondary sponsor category [1] 286296 0
Hospital
Name [1] 286296 0
Department of Gastroenterology and Hepatology, Royal Adelaide Hospital
Address [1] 286296 0
Department of Gastroenterology and Hepatology
Level 7 Q7 North Wing
Royal Adelaide Hospital
North Terrace
Adelaide SA 5000
Country [1] 286296 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 289525 0
Royal Adelaide Hospital Reserach Ethics Comittee
Ethics committee address [1] 289525 0
The Royal Adelaide Hospital Research Ethics Committee,
Level 3, Hanson Institute IMVS Building
North Terrace
Adelaide SA 5000

Ethics committee country [1] 289525 0
Australia
Date submitted for ethics approval [1] 289525 0
Approval date [1] 289525 0
02/05/2011
Ethics approval number [1] 289525 0
110427

Summary
Brief summary
The purpose of this study is to explore the importance of gut sweet taste sensors in the regulation of sugar control, appetite and body weight during health, obesity and after bariatric surgery. The findings of the current study may provide further insights into the mechanisms underlying the development of obesity and diabetes mellitus, which, in turn, can have a great potential therapeutic implication.

Hypothesis:
We hypothesise that the number of these sweet taste receptors will be markedly reduced in the small intestine of morbidly obese patients but will be increased after bariatric surgery, leading to increased incretin responses and subsequently, better glucose control and body weight (via high GLP-1). We further hypothesise that the greater release of GLP- 1 (thus, release of insulin) after RYGB over LAGB is related to the higher expression of small intestinal sweet taste receptors, leading to better glucose control and weight loss in these patients.

This study, therefore, aims to evaluate the expression of small intestinal sweet taste receptors before and after a sugar ‘meal’ and its relationship to GLP-1 concentration, glucose control and body weight in morbidly obese subjects and patients who undergo RYGB and LAGB.
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 41182 0
Dr Nam Q Nguyen
Address 41182 0
Department of Gastroenterology and Hepatology,
Q7 Level 7 North Wing
Royal Adelaide Hospital
North Terrace
Adelaide SA 5000
Country 41182 0
Australia
Phone 41182 0
+61 8 8222 2412
Fax 41182 0
Email 41182 0
quoc.nguyen@health.sa.gov.au
Contact person for public queries
Name 41183 0
Dr Nam Q Nguyen
Address 41183 0
Department of Gastroenterology and Hepatology,
Q7 Level 7 North Wing
Royal Adelaide Hospital
North Terrace
Adelaide SA 5000
Country 41183 0
Australia
Phone 41183 0
+61 8 8222 2412
Fax 41183 0
Email 41183 0
quoc.nguyen@health.sa.gov.au
Contact person for scientific queries
Name 41184 0
Dr Nam Q Nguyen
Address 41184 0
Department of Gastroenterology and Hepatology,
Q7 Level 7 North Wing
Royal Adelaide Hospital
North Terrace
Adelaide SA 5000
Country 41184 0
Australia
Phone 41184 0
+61 8 8222 2412
Fax 41184 0
Email 41184 0
quoc.nguyen@health.sa.gov.au

No information has been provided regarding IPD availability
Summary results
No Results