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Trial registered on ANZCTR


Registration number
ACTRN12615000088549
Ethics application status
Approved
Date submitted
20/01/2015
Date registered
3/02/2015
Date last updated
3/02/2015
Type of registration
Retrospectively registered

Titles & IDs
Public title
Effects of Hydroxycitrate (HCA) on intestinal glucose absorption and incretin release
Scientific title
A randomised placebo controlled crossover trial to evaluate the effects of hydroxycitrate (HCA) on blood glucose concentrations, glucose absorption, and plasma GIP and GLP-1 secretion, in response to intraduodenal glucose infusion, in healthy humans and patients with type 2 diabetes mellitus
Secondary ID [1] 286016 0
Nil
Universal Trial Number (UTN)
Trial acronym
Linked study record

Health condition
Health condition(s) or problem(s) studied:
Type 2 diabetes mellitus 293978 0
Condition category
Condition code
Metabolic and Endocrine 294278 294278 0 0
Diabetes

Intervention/exposure
Study type
Interventional
Description of intervention(s) / exposure
Subjects will be studied twice in crossover fashion, with at least 5 days between study days. On each day, the subject will arrive at the Royal Adelaide Hospital at approximately 0830. An intraduodenal catheter (diameter 3.5 mm; Dentsleeve, Ontario, Canada) will be inserted through an anaesthetised nostril and allowed to pass through the stomach and into the duodenum by peristalsis. The assembly will contain an infusion channel, located about 12 cm distally from the pylorus. The correct positioning of the catheter will be maintained by continuous measurement of the transmucosal potential difference (TMPD) from manometry side holes in the antrum and duodenum. For this purpose, a cannula filled with sterile saline will be placed subcutaneously in the left forearm and used as a reference electrode. The antral and duodenal channels will be perfused with degassed 0.9 % saline at 0.15 ml/minute. An intravenous cannula will be also be inserted to facilitate subsequent blood sampling.

At T = -60, 4667mg of SuperCitriMax (Registered Trademark, InterHealth Nutraceuticals Incorporated) containing 2800mg of HCA, dissolved in 420 ml water or placebo (saline matched for osmolality) will be administered intraduodenally over 60 minutes. Then, at T = 0, intraduodenal glucose will be administered at a rate of 2 ml/min of 25% glucose (2 kcal/minute) for 120 minutes along with (in healthy subjects only) 5 g of 3-O-methylglcuose to facilitate measurement of exogenous glucose absorption.
Intervention code [1] 290995 0
Treatment: Other
Comparator / control treatment
Water
Control group
Placebo

Outcomes
Primary outcome [1] 294073 0
Blood glucose concentrations
Timepoint [1] 294073 0
Concentrations measured from venous blood taken at T = -60, 0, 15, 30, 45, 60, 90, 120, 150, 180, 210 and 240 minutes
Secondary outcome [1] 312470 0
Serum 3-O-methylglucose concentrations
Timepoint [1] 312470 0
Concentrations measured from venous blood taken at T = 0, 15, 30, 45, 60, 90, 120, 150, 180, 210 and 240 minutes
Secondary outcome [2] 312471 0
Plasma total GLP-1 concentrations
Timepoint [2] 312471 0
Concentrations measured from venous blood taken at T = -60, 0, 15, 30, 45, 60, 90, 120, 150, 180, 210 and 240 minutes
Secondary outcome [3] 312472 0
Plasma total GIP concentrations
Timepoint [3] 312472 0
Concentrations measured from venous blood taken at T = -60, 0, 15, 30, 45, 60, 90, 120, 150, 180, 210 and 240 minutes
Secondary outcome [4] 312473 0
Plasma insulin concentrations
Timepoint [4] 312473 0
Concentrations measured from venous blood taken at T = -60, 0, 15, 30, 45, 60, 90, 120, 150, 180, 210 and 240 minutes
Secondary outcome [5] 312474 0
Plasma glucagon concentrations
Timepoint [5] 312474 0
Concentrations measured from venous blood taken at T = -60, 0, 15, 30, 45, 60, 90, 120, 150, 180, 210 and 240 minutes
Secondary outcome [6] 312475 0
Gastrointestinal sensations of hunger, fullness and nausea.
Timepoint [6] 312475 0
Assessed by visual analogue questionnaire completed at T = -60, 0, 15, 30, 45, 60, 90, 120, 150, 180, 210 and 240 minutes

Eligibility
Key inclusion criteria
Healthy subjects:
- Males or females aged 18 – 70 years
- Body mass index (BMI) 19 - 30 kg/m2

Type 2 diabetes patients:
Patients with type 2 diabetes
- Patients with a diagnosis of type 2 diabetes by WHO criteria (plasma glucose greater than or equal to 7 mmol/L fasting, or greater than or equal to 11.1 mmol/L two hours after a glucose challenge) or with a history of HbA1c greater than or equal to 6.5%.
- Managed by diet alone.
- HbA1c between 6.0 and 8.5%
- Body mass index (BMI) 20 - 35 kg/m2
- Age 18 – 70 years
Minimum age
18 Years
Maximum age
70 Years
Gender
Both males and females
Can healthy volunteers participate?
Yes
Key exclusion criteria
- Use of any medication that may influence gastrointestinal motor function within 48 hours or 5 half lives of the study, specifically: opiates, anticholinergics, levodopa, calcium-channel antagonists, beta blockers, clonidine, nitrates, tricyclic antidepressants, selective serotonin re-uptake inhibitors, phosphodiesterase type 5 inhibitors, sumatriptan, metoclopramide, domperidone, cisapride, tegaserod, erythromycin
- Intake of >20 g alcohol on a daily basis, or >10 cigarettes per day
- History of gastrointestinal disease, including significant upper or lower gastrointestinal symptoms, or previous gastrointestinal surgery (other than uncomplicated appendicectomy)
- Impaired renal or liver function (as assessed by calculated creatinine clearance < 90 mL/min or abnormal liver function tests)
- Donation of blood within the previous 3 months
- Participation of other studies within the previous 3 months

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)
numbered envelopes
Methods used to generate the sequence in which subjects will be randomised (sequence generation)
computer-generated random number table
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
Phase 2
Type of endpoint(s)
Efficacy
Statistical methods / analysis

Recruitment
Recruitment status
Completed
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] 290608 0
Government body
Name [1] 290608 0
National Health and Medical Research Council of Australia
Address [1] 290608 0
GPO Box 1421
Canberra ACT 2601
Country [1] 290608 0
Australia
Primary sponsor type
University
Name
University of Adelaide
Address
North Terrace
Adelaide SA 5000
Country
Australia
Secondary sponsor category [1] 289294 0
None
Name [1] 289294 0
Address [1] 289294 0
Country [1] 289294 0

Ethics approval
Ethics application status
Approved
Ethics committee name [1] 292239 0
Royal Adelaide Hospital Human Research Ethics Committee
Ethics committee address [1] 292239 0
Royal Adelaide Hospital North Terrace
Adelaide SA 5000
Ethics committee country [1] 292239 0
Australia
Date submitted for ethics approval [1] 292239 0
Approval date [1] 292239 0
13/08/2012
Ethics approval number [1] 292239 0
120714

Summary
Brief summary
Hydroxycitric acid (HCA), derived from the fruit Garcinia cambogia, reduces the rate of glucose absorption and decreases postprandial glycaemia in rodents, but its effects in humans are unknown. We aim to investigate the effects of small intestinal perfusion with HCA on glucose absorption, incretin (GIP and GLP-1) release and glycaemia in response to a subsequent intraduodenal glucose infusion in both health and type 2 diabetes.

Healthy subjects and patients with type 2 diabetes will received an intraduodenal infusion of HCA (2800mg in water) or control (water alone) over 60min, followed by 60g glucose infused over 120min, in a double blind randomized crossover design. In the healthy subjects, 5g 3-O-methylglucose (3-OMG) will be co-infused with glucose as a marker of glucose absorption. Blood will be sampled frequently for subsequent assays.
Trial website
Trial related presentations / publications
Data presented in part at Australian Gastroenterology Week, Melbourne, October 2013, and accompanying abstract published:
Thazhath SS, Bound M, Jones K, Horowitz M, Rayner C. Effect of hydroxycitric acid on the glycaemic response to a small intestinal glucose load in healthy humans (Abstract). Journal of Gastroenterology and Hepatology 2013; 28 (Suppl. 2): 135
Public notes

Contacts
Principal investigator
Name 54262 0
Prof Chris Rayner
Address 54262 0
Discipline of Medicine Royal Adelaide Hospital North Terrace Adelaide SA 5000
Country 54262 0
Australia
Phone 54262 0
+61 8 82222916
Fax 54262 0
Email 54262 0
chris.rayner@adelaide.edu.au
Contact person for public queries
Name 54263 0
Prof Chris Rayner
Address 54263 0
Discipline of Medicine Royal Adelaide Hospital North Terrace Adelaide SA 5000
Country 54263 0
Australia
Phone 54263 0
+61 8 82222916
Fax 54263 0
Email 54263 0
chris.rayner@adelaide.edu.au
Contact person for scientific queries
Name 54264 0
Prof Chris Rayner
Address 54264 0
Discipline of Medicine Royal Adelaide Hospital North Terrace Adelaide SA 5000
Country 54264 0
Australia
Phone 54264 0
+61 8 82222916
Fax 54264 0
Email 54264 0
chris.rayner@adelaide.edu.au

No information has been provided regarding IPD availability
Summary results
Have study results been published in a peer-reviewed journal?
Other publications
Have study results been made publicly available in another format?
Results – basic reporting
Results – plain English summary