Microvascular Insulin Resistance and Mixed Meal Challenge

Menzies Institute for Medical Research

Status: Unknown

Conditions: Insulin Resistance

Treatments: Other: Glucose Challenge; Other: Mixed Meal Challenge

Study type: Interventional

Funder types: Other

Identifiers

NCT02708875

H14086

Details and patient eligibility

About

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.

Full 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.

Enrollment: 45 estimated patients

Sex: All

Ages: 18 to 70 years old

Volunteers: Accepts Healthy Volunteers

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.

Trial design

Primary purpose: Screening

Allocation: Randomized

Interventional model: Crossover Assignment

Masking: None (Open label)

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45 participants in 2 patient groups

Mixed Meal Challenge

Experimental group

Description:

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.

Treatment:

Other: Mixed Meal Challenge

Glucose Challenge

Active Comparator group

Description:

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.

Treatment:

Other: Glucose Challenge