Clinical trial NCT02708875: Microvascular Insulin Resistance and Mixed Meal Challenge
Official title: Microvascular Insulin Resistance and Mixed Meal Challenge
Study type: INTERVENTIONAL
Overall status: UNKNOWN
Phase: NA
Conditions: Insulin Resistance
Keywords: Microvascular
Insulin resistance
Mixed Meal
Glucose tolerance
Lead sponsor: Menzies Institute for Medical Research
Sponsor class: OTHER
Collaborators: name: Deakin University
First posted: 2016-03-15
Enrollment: 45
Sex: ALL
Minimum age (years): 18
Maximum age (years): 70
Standard ages: ADULT
OLDER_ADULT
Accepts healthy volunteers: yes
Allocation: RANDOMIZED
Intervention model: CROSSOVER
Primary purpose: SCREENING

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.

Eligibility criteria: 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.

Primary outcomes:
measure: Change from baseline in muscle microvascular blood flow
timeFrame: 1 hr
Secondary outcomes:
measure: Changes in blood glucose levels
timeFrame: 2 hr
measure: Changes in plasma insulin levels
timeFrame: 2hr
measure: Changes in the respiratory exchange ratio (RER)
timeFrame: 1 hr
Other outcomes:
Locations:
city: Hobart
country: Australia
facility: Menzies Institute for Medical Research
state: Tasmania
city: Burwood
country: Australia
facility: Deakin University
state: Victoria
Study officials:
affiliation: Menzies Institute for Medical Research
name: Michelle A Keske, PhD
role: PRINCIPAL_INVESTIGATOR
References: