Insulin Resistance
Conditions
Keywords
Microvascular, Insulin resistance, Mixed Meal, Glucose tolerance
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.
Interventions
OTHERMixed Meal Challenge
Liquid mixed meal (300 calories - fat, carbohydrate, and protein).
OTHERGlucose Challenge
Glucose drink (50g glucose)
Sponsors
Deakin University
Menzies Institute for Medical Research
Study design
Allocation
RANDOMIZED
Intervention model
CROSSOVER
Primary purpose
SCREENING
Masking
NONE
Eligibility
Sex/Gender
ALL
Age
18 Years to 70 Years
Healthy volunteers
Yes
Inclusion criteria
* 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
Exclusion criteria
* 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.
Design outcomes
Primary
| Measure | Time frame | Description |
|---|---|---|
| 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
| Measure | Time frame | Description |
|---|---|---|
| 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. |
Countries
Australia
Outcome results
None listed