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Trial registered on ANZCTR


Registration number
ACTRN12619001666112
Ethics application status
Approved
Date submitted
7/11/2019
Date registered
28/11/2019
Date last updated
28/11/2019
Date data sharing statement initially provided
28/11/2019
Type of registration
Prospectively registered

Titles & IDs
Public title
Effects of combined administration of L-tryptophan and lauric acid on gut functions, and blood glucose control in healthy humans
Scientific title
Effects of combined administration of L-tryptophan and lauric acid on gut functions, including gastric emptying, and gut hormone release, and blood glucose control in healthy humans
Secondary ID [1] 299739 0
Nil known
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Type 2 diabetes 315090 0
Obesity 315091 0
Healthy Human Gastrointestinal Physiology 315092 0
Condition category
Condition code
Diet and Nutrition 313424 313424 0 0
Obesity
Oral and Gastrointestinal 313425 313425 0 0
Normal oral and gastrointestinal development and function
Metabolic and Endocrine 313426 313426 0 0
Diabetes

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
We will investigate the effects of a combination of intraduodenally administered L-tryptophan and lauric acid on gut motor functions (including antropyloroduodenal motility and gastric emptying), gut hormone release and blood glucose in response to a mixed-nutrient drink in healthy volunteers.

Each volunteer will be studied on four occasions, separated by at least 3 (and up to 7) days. On each occasion, participants will receive, in randomised, double-blind fashion, a 45-min intraduodenal infusion of:
(i) L-tryptophan at 0.10 kcal/min (1.1 g/45 min),
(ii) lauric acid at 0.3 kcal/min (1.5 g/45 min),
(iii) combination of (i) and (ii), or
(iv) saline (control)

On each study occasion, participants will attend the laboratory at ~ 08:00 hr, after fasting overnight, and will be intubated, via an anaesthetised nostril, with a small-diameter nasoduodenal manometric catheter consisting of 16 channels plus an infusion port. The catheter will be allowed to pass through the stomach and into the duodenum. Once the catheter is positioned correctly, with the sleeve sensor straddling the pylorus, fasting motility will be observed until a phase III of the interdigestive migrating motor complex occurs. Immediately following the cessation of phase III, and during phase I, an intravenous cannula will be inserted for blood sampling (to measure gut hormones and blood glucose).
At t = -10 min, participants will complete a VAS questionnaire, then at t = 0 min, a baseline blood sample and breath sample (to measure gastric emptying), will be taken, and participants will complete another VAS questionnaire. At t = 0 min, the infusion will commence, and continue until t = 45 min. At t = 30 min, participants will be given a mixed-nutrient drink (containing 500 kcal, 74 g carbohydrates) to consume within 2 min, which will be marked with carbon-13 acetate to facilitate the measurement of gastric emptying using 13C-breath test.

- Blood samples will be taken at the following time points:
t = 0, 15, 30, 40, 50, 60, 75, 90, 120, 150 min.
- Breath samples will be taken at the following time points:
t = 0, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, 210 min.
- VAS questionnaires will be complete at the following time points:
t = -10, 0, 15, 30, 40, 50, 60, 75, 90, 105, 120, 135, 150 min.
- Antropyloroduodenal motility will be continuously measured from t = -10 to 150 min.

At t = 150 min, the intraduodenal tube will be removed and breath testing will continue until t = 210 min. Participants will then be served a light lunch, consisting of a sandwich, fruit/museli bar, and water, and then allowed to leave the laboratory.
Intervention code [1] 316002 0
Treatment: Other
Comparator / control treatment
Saline
Control group
Placebo

Outcomes
Primary outcome [1] 321902 0
Changes in plasma glucose concentration
Timepoint [1] 321902 0
Plasma will be obtained from blood samples taken at t = 0, 15, 30, 40 , 50, 60, 75, 90, 120, and 150 min.
Primary outcome [2] 321977 0
Changes in C-peptide, and other gut hormone concentrations, including cholecystokinin, GLP-1 and GIP, This outcome is of an exploratory nature so that other gut hormones to be measured may be decided upon based on the effects of this intervention on plasma glucose, and other outcomes.
Timepoint [2] 321977 0
Plasma will be obtained from blood samples taken at t = 0, 15, 30, 40 , 50, 60, 75, 90, 120, and 150 min.
Primary outcome [3] 321978 0
Gastric emptying will be measured using breath samples
Timepoint [3] 321978 0
Breath samples will be collected at t = -10, 30, 35. 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, 190, 200, and 210 min.
Secondary outcome [1] 376632 0
Antropyloroduodenal motility measured by nasoduodenal manometric catheter
Timepoint [1] 376632 0
Continuous measurement from t = - 10 to 150 min.
Secondary outcome [2] 376633 0
Hunger sensation will be measured using a VAS questionnaire
Timepoint [2] 376633 0
VAS questionnaires will be completed at t = -10, 0, 15, 30, 40 , 50, 60, 75, 90, 105, 120, 135 and 150 min.
Secondary outcome [3] 376634 0
Fullness sensation will be measured using a VAS questionnaire
Timepoint [3] 376634 0
VAS questionnaires will be completed at t = -10, 0, 15, 30, 40 , 50, 60, 75, 90, 105, 120, 135 and 150 min.
Secondary outcome [4] 376635 0
Desire to eat will be measured using a VAS questionnaire
Timepoint [4] 376635 0
VAS questionnaires will be completed at t = -10, 0, 15, 30, 40 , 50, 60, 75, 90, 105, 120, 135 and 150 min.
Secondary outcome [5] 377144 0
Prospective consumption will be measured using a VAS questionnaire
Timepoint [5] 377144 0
VAS questionnaires will be completed at t = -10, 0, 15, 30, 40 , 50, 60, 75, 90, 105, 120, 135 and 150 min.
Secondary outcome [6] 377145 0
Nausea will be measured using a VAS questionnaire
Timepoint [6] 377145 0
VAS questionnaires will be completed at t = -10, 0, 15, 30, 40 , 50, 60, 75, 90, 105, 120, 135 and 150 min.

Eligibility
Key inclusion criteria
Healthy lean (BMI 19 - 25 kg/m2) male volunteers aged between 18-55 years, non-smokers, and without significant illness will be included in the study.
Minimum age
18 Years
Maximum age
55 Years
Gender
Males
Can healthy volunteers participate?
Yes
Key exclusion criteria
Significant upper GI symptoms or history of GI disease or surgery
Current gallbladder or pancreatic disease
Cardiovascular or respiratory disease
Any other illnesses as assessed by the investigator (including chronic illnesses not explicitly listed above)
Use of prescribed or non-prescribed medications (including vitamins and herbal supplements) which may affect energy metabolism, gastrointestinal function, body weight or appetite (e.g. domperidone and cisapride, anticholinergic drugs (e.g. atropine), metoclopramide, erythromycin, hyoscine, orlistat, green tea extracts, Astragalus, St Johns Wort etc.)
Lactose intolerance/ other food allergy(ies)
Individuals with low ferritin levels (males <30 ng/mL), or who have donated blood in the 12 weeks prior to taking part in the study
High performance athletes
Current intake of > 2 standard drinks on > 5 days per week (>140g/week)
Current smokers of cigarettes/cigars/marijuana
Current intake of any illicit substance
Vegetarians
Inability to comprehend study protocol
Restrained eaters (score > 12 on the three factor eating questionnaire)

Study design
Purpose of the study
Treatment
Allocation to intervention
Randomised controlled trial
Procedure for enrolling a subject and allocating the treatment (allocation concealment procedures)
Eligible volunteers are assigned a participant number and randomised treatment for each study visit. Randomisation will involve contacting the holder (study assistant) of the randomisation table to inform them of participants details and study dates. The unblinded study assistant is therefore, responsible for allocating a random treatment to the participant and preparing the study treatment on each study day.
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
The randomisation will be generated using a randomisation plan generator available at www.randomization.com
Masking / blinding
Blinded (masking used)
Who is / are masked / blinded?
The people receiving the treatment/s
The people administering the treatment/s
The people assessing the outcomes
The people analysing the results/data
Intervention assignment
Crossover
Other design features
Phase
Not Applicable
Type of endpoint(s)
Pharmacokinetics / pharmacodynamics
Statistical methods / analysis

Recruitment
Recruitment status
Not yet 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

Funding & Sponsors
Funding source category [1] 304214 0
Government body
Name [1] 304214 0
National Health and Medical Research Council (NHMRC)
Address [1] 304214 0
National Health and Medical Research Council
GPO Box 1421
Canberra ACT 2601
Country [1] 304214 0
Australia
Primary sponsor type
Individual
Name
Professor Christine Feinle-Bisset
Address
School of Medicine, University of Adelaide
Level 5, Adelaide Health and Medical Sciences Building
4 North Terrace
Adelaide SA 5005
Country
Australia
Secondary sponsor category [1] 304446 0
Individual
Name [1] 304446 0
Professor Michael Horowitz
Address [1] 304446 0
School of Medicine, University of Adelaide
Level 5, Adelaide Health and Medical Sciences Building
4 North Terrace
Adelaide SA 5005
Country [1] 304446 0
Australia

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 304676 0
Central Adelaide Local Health Network Human Research Ethics Committee
Ethics committee address [1] 304676 0
Level 3, Roma Mitchell House
North Tce
Adelaide, SA 5000
Ethics committee country [1] 304676 0
Australia
Date submitted for ethics approval [1] 304676 0
06/06/2019
Approval date [1] 304676 0
18/06/2019
Ethics approval number [1] 304676 0
R20130611

Summary
Brief summary
Recent studies have demonstrated that specific nutrients, including lauric acid and L-tryptophan, have energy intake-suppressant and blood glucose-regulatory effects via several pathways, including stimulation of gut hormones and motility, and the slowing of gastric emptying.

We aim to investigate the hypothesis that the combined intraduodenal administration of lauric acid and tryptophan, compared with the individual nutrients, will more potently stimulate gut functions, including gut hormones, and gastric emptying, associated with reduced postprandial blood glucose
Trial website
Trial related presentations / publications
Public notes

Contacts
Principal investigator
Name 97822 0
Prof Christine Feinle-Bisset
Address 97822 0
School of Medicine, University of Adelaide
Level 5, AHMS Building
4 North Terrance
Adelaide SA 5005
Country 97822 0
Australia
Phone 97822 0
+61 8 83136053
Fax 97822 0
Email 97822 0
christine.feinle@adelaide.edu.au
Contact person for public queries
Name 97823 0
Ms Penelope Fitzgerald
Address 97823 0
School of Medicine, University of Adelaide
Level 5, AHMS Building
4 North Terrance
Adelaide SA 5005
Country 97823 0
Australia
Phone 97823 0
+61 8 83136278
Fax 97823 0
Email 97823 0
penelope.fitzgerald@adelaide.edu.au
Contact person for scientific queries
Name 97824 0
Prof Christine Feinle-Bisset
Address 97824 0
School of Medicine, University of Adelaide
Level 5, AHMS Building
4 North Terrance
Adelaide SA 5005
Country 97824 0
Australia
Phone 97824 0
+61 8 83136053
Fax 97824 0
Email 97824 0
christine.feinle@adelaide.edu.au

Data sharing statement
Will individual participant data (IPD) for this trial be available (including data dictionaries)?
No
No/undecided IPD sharing reason/comment
In line with intellectual property agreement
What supporting documents are/will be available?
No other documents available
Summary results
No Results