Microvascular Insulin Resistance and Mixed Meal Challenge
- Conditions
- Insulin Resistance
- Interventions
- Other: Mixed Meal ChallengeOther: Glucose Challenge
- Registration Number
- NCT02708875
- Lead Sponsor
- Menzies Institute for Medical Research
- Brief Summary
Insulin resistance (or pre-diabetes) is diagnosed using the oral glucose tolerance test. However, high blood glucose levels during this test may adversely impact on microvascular function. Investigators will determine whether a liquid mixed meal challenge (from carbohydrate, protein and fat) is a more appropriate test for assessing microvascular-derived insulin resistance.
- Detailed Description
After consuming a meal, 80% of glucose is disposed in skeletal muscle. Our research group has demonstrated that microvascular blood flow in skeletal muscle plays an integral role in this process. Physiological doses of insulin stimulate microvascular blood flow, and that this increase is associated with enhanced glucose uptake by muscle. This microvascular action of insulin is lost during insulin resistance and type 2 diabetes.
The oral glucose tolerance test (GTT) is the gold standard for assessing insulin resistance and pre-diabetes and is used world-wide. However high blood glucose levels following a glucose load may adversely impact on microvascular function. The aim of this project is to determine whether a mixed meal challenge (liquid drink consisting of carbohydrate, fat and protein) is a better test for assessing microvascular-derived insulin resistance.
Recruitment & Eligibility
- Status
- UNKNOWN
- Sex
- All
- Target Recruitment
- 45
- Aged 18-70 years.
- Normal to overweight (BMI 19-35 kg/m2).
- Normotensive (Seated brachial blood pressure <160/100 mmHg).
- Considered healthy (HbA1c <6.5 %) or have clinically diagnosed type 2 diabetes.
- Either have a parent with T2D, or no family history of type 2 diabetes for two generations.
- Have given signed informed consent to participate in the study
- Age <18 yrs or >70 yrs
- Morbidly obese with a BMI ≥36 kg/m2
- History of myocardial infarction or stroke
- History of malignancy within past 5 years (except for non-melanoma skin cancers)
- Current smoker
- History of severe liver disease
- History of drug or alcohol abuse
- Elective major surgery during the course of the study
- Pregnancy/lactation
- Participation or intention to participate in another clinical research study during the study period.
Study & Design
- Study Type
- INTERVENTIONAL
- Study Design
- CROSSOVER
- Arm && Interventions
Group Intervention Description Mixed Meal Challenge Mixed Meal Challenge Participants will consume a liquid mixed meal (\~300 calories - fat, carbohydrate, and protein) for monitoring changes in glucose metabolism, plasma insulin and microvascular responses in skeletal muscle over 2 hours. Glucose Challenge Glucose Challenge Participants will consume a glucose challenge (50g glucose) for monitoring changes in glucose metabolism, plasma insulin and microvascular responses in skeletal muscle over 2 hours.
- Primary Outcome Measures
Name Time Method Change from baseline in muscle microvascular blood flow 1 hr Microvascular responses will be measured by contrast enhanced ultrasound before and 1hr after each challenge.
- Secondary Outcome Measures
Name Time Method Changes in blood glucose levels 2 hr Blood glucose levels will be measured at 0, 15, 30, 60, 90 and 120 min following each challenge.
Changes in plasma insulin levels 2hr Plasma insulin levels will be measured at 0, 15, 30, 60, 90 and 120 min following each challenge.
Changes in the respiratory exchange ratio (RER) 1 hr Changes in RER will be measured by metabolic cart during each challenge.
Trial Locations
- Locations (2)
Deakin University
🇦🇺Burwood, Victoria, Australia
Menzies Institute for Medical Research
🇦🇺Hobart, Tasmania, Australia