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Trial registered on ANZCTR


Registration number
ACTRN12623000233628
Ethics application status
Approved
Date submitted
13/02/2023
Date registered
6/03/2023
Date last updated
6/03/2023
Date data sharing statement initially provided
6/03/2023
Type of registration
Retrospectively registered

Titles & IDs
Public title
Examining the role of gut taste receptors in food preferences, weight loss, and metabolic improvements after bariatric surgery.
Scientific title
Examining the role of gut taste receptors in food preferences, weight loss, and metabolic improvements after bariatric surgery.
Secondary ID [1] 308939 0
None
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
obesity 328948 0
bariatric surgery 329059 0
Condition category
Condition code
Metabolic and Endocrine 325937 325937 0 0
Metabolic disorders
Surgery 326041 326041 0 0
Other surgery

Intervention/exposure
Study type
Observational
Patient registry
False
Target follow-up duration
Target follow-up type
Description of intervention(s) / exposure
Exposure is bariatric surgery (sleeve gastrectomy or Roux-en-Y gastric bypass). Observation period is during the pre-operative work-up period until 12-months post surgery.

Observation involves food and alcohol preference questionnaires, blood tests, weight record, and gastrointestinal biopsies at 3 timepoints: pre-operative work-up, bariatric surgery, and approximately 12 months (range 6-18 months) post-surgical follow-up.
Intervention code [1] 325386 0
Not applicable
Comparator / control treatment
No control group. Study observes within-person changes over time.
Control group
Uncontrolled

Outcomes
Primary outcome [1] 333783 0
Preference for highly palatable fatty foods before vs 12 months after bariatric surgery

This will be assessed by the Fat Preference Questionnaire.
Timepoint [1] 333783 0
Pre-operatively
Day of surgery (after pre-operative very low energy diet [VLED])
12-months post-surgery
Primary outcome [2] 333784 0
Changes in gastrointestinal expression of taste-related genes before vs 12 months after bariatric surgery

This will be assessed through quantitative PCR and protein analysis of taste receptor and taste-related genes in the stomach and small bowel mucosal biopsies.
Timepoint [2] 333784 0
Pre-operatively
Day of surgery (after pre-operative very low energy diet [VLED])
12-months post-surgery
Primary outcome [3] 334048 0
Preference for highly palatable sweet foods before vs 12 months after bariatric surgery

This will be assessed by the Sweet Taste Questionnaire.
Timepoint [3] 334048 0
Pre-operatively
Day of surgery (after pre-operative very low energy diet [VLED])
12-months post-surgery
Secondary outcome [1] 418293 0
Alcohol consumption and drinking preferences.

Assessed via The Drinking Behaviour Questionnaire
Timepoint [1] 418293 0
Pre-operatively
Day of surgery (after pre-operative very low energy diet [VLED])
12-months post-surgery
Secondary outcome [2] 418294 0
Body weight

Measured on calibrated medical weighing scales in kilograms and change from pre-operative to day-of-surgery to post-operative follow-up calculated as percentage of total weight loss.
Timepoint [2] 418294 0
Pre-operatively
Day of surgery (after pre-operative very low energy diet [VLED])
12-months post-surgery
Secondary outcome [3] 418295 0
Fasting blood glucose
Timepoint [3] 418295 0
Pre-operatively
Day of surgery (after pre-operative very low energy diet [VLED])
12-months post-surgery
Secondary outcome [4] 418296 0
Fasting lipid profile

Assessed via serum analysis.
Timepoint [4] 418296 0
Pre-operatively
Day of surgery (after pre-operative very low energy diet [VLED])
12-months post-surgery

Eligibility
Key inclusion criteria
1. Adults (age 18 years or over)
2. Waiting to undergo sleeve gastrectomy or Roux-en-Y gastric bypass
Minimum age
18 Years
Maximum age
No limit
Sex
Both males and females
Can healthy volunteers participate?
No
Key exclusion criteria
1. Using medication for the treatment of diabetes and/or obesity
2. Waiting to undergo revisional surgery
3. Previous intestinal surgery that has resulted in alteration to stomach or small bowel anatomy
4. Unable to provide informed consent

Study design
Purpose
Natural history
Duration
Longitudinal
Selection
Defined population
Timing
Prospective
Statistical methods / analysis
Differences in the expression of taste-related genes after (vs before) surgery will be compared with paired Student’s T-tests or Wilcoxon-matched pair tests. Relationships will be examined between changes in gene expression and food preferences, weight loss, blood glucose and lipids using correlation coefficients and regression analyses.

Recruitment
Recruitment status
Recruiting
Date of first participant enrolment
Anticipated
Actual
31/01/2023
Date of last participant enrolment
Anticipated
31/01/2024
Actual
Date of last data collection
Anticipated
31/01/2025
Actual
Sample size
Target
50
Accrual to date
1
Final
Recruitment in Australia
Recruitment state(s)
VIC

Funding & Sponsors
Funding source category [1] 313151 0
Government body
Name [1] 313151 0
National Health and Medical Research Council
Country [1] 313151 0
Australia
Primary sponsor type
Hospital
Name
St Vincent's Hospital Melbourne
Address
41 Victoria Parade, Fitzroy, Victoria, 3065
Country
Australia
Secondary sponsor category [1] 314864 0
None
Name [1] 314864 0
Address [1] 314864 0
Country [1] 314864 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 312391 0
St Vincent's Hospital Melbourne
Ethics committee address [1] 312391 0
41 Victoria Parade, Fitzroy, Victoria, 3065
Ethics committee country [1] 312391 0
Australia
Date submitted for ethics approval [1] 312391 0
Approval date [1] 312391 0
24/11/2022
Ethics approval number [1] 312391 0

Summary
Brief summary
An unintended but common outcome of bariatric surgeries is reduced preference for sweet and fatty foods. It is not known why this occurs. This study will examine whether changes in food preferences after bariatric surgery are related to changes in taste receptors in the gut.

In volunteers undergoing sleeve gastrectomy or gastric bypass, food preferences and gut taste receptors will be examined and compared before and 12 months after surgery. Relationships between food preferences, gut taste receptors, weight loss, blood glucose and lipid profile will be examined. This will indicate whether changes in gut taste receptors are related to the effects of bariatric surgery.

Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 124498 0
Dr Michael Hii
Address 124498 0
St Vincent's Hospital Melbourne
41 Victoria Parade, Fitzroy, Victoria 3065

Melbourne Gastro Oesophageal Surgery
100 Victoria Parade, East Melbourne, Victoria, 3002
Country 124498 0
Australia
Phone 124498 0
+61 3 9416 4418
Fax 124498 0
Email 124498 0
mhii@mgos.com.au
Contact person for public queries
Name 124499 0
Dr Rosalind Walmsley
Address 124499 0
St Vincent's Hospital Melbourne
41 Victoria Parade, Fitzroy, Victoria 3065
Country 124499 0
Australia
Phone 124499 0
+61 03 9906 5625
Fax 124499 0
Email 124499 0
rosalind.walmsley@student.unimelb.edu.au
Contact person for scientific queries
Name 124500 0
A/Prof Priya Sumithran
Address 124500 0
Department of Medicine, University of Melbourne, St Vincent's Hospital Melbourne
Clinical Sciences Building, Level 4 / 29 Regent Street, Fitzroy, Victoria, 3065
Country 124500 0
Australia
Phone 124500 0
+61 03 9231 2592
Fax 124500 0
Email 124500 0
priyas@unimelb.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
Yes
What data in particular will be shared?
individual participant data underlying published results will be shared after de-identification
When will data be available (start and end dates)?
beginning immediately following publication and ending 5 years after main results publication
Available to whom?
to researchers who provide a methodologically sound proposal
Available for what types of analyses?
for investigator-initated research
How or where can data be obtained?
access subject to approval by investigating team (email priyas@unimelb.edu.au)


What supporting documents are/will be available?

No Supporting Document Provided



Results publications and other study-related documents

Documents added manually
No documents have been uploaded by study researchers.

Documents added automatically
No additional documents have been identified.