Brown Adipose Tissue Activation: Effect of Exercise Training and Irisin

Study Overview
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Brief Summary
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This study investigates the brown adipose tissue (BAT) activation and metabolism using positron emission tomography (PET) imaging before and after exercise training intervention at fasting state under normal room temperature and during cold stimulation.The investigators hypothesize that BAT glucose uptake is increased after exercise and BAT becomes metabolically more active. Understanding the mechanisms of BAT activation and the role of exercise in humans is crucial to combat epidemic of obesity and diabetes.

Detailed Description
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Exercise training has been suggested to activate and recruit human BAT through the activation of sympathetic nervous system and contracting skeletal muscles by the release of myokines such as lactate and irisin that signal WAT to induce expression of beige adipocytes. It has been also suggested that exercise training could enhance the metabolism of already existed functional BAT by increasing uncoupling protein-1 (UCP-1) gene transcription, mitochondrial biogenesis and hyperplasia. This is of clinical relevance because brown fat activation has been found to improve metabolic factors linked to obesity and diabetes. In this study the investigators use a PET radiotracer 2-[18F] flouro-2-deoxy-D-glucose (FDG) to quantify the glucose uptake in BAT, whie adipose tissue and the muscle.The participants are scanned thrice at fast in this study once at room temperature, second at cold exposure and third after six weeks of exercise at cold exposure. This study will provide an insight about the role of exercise in activation of BAT metabolism.

Official Title
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Brown Adipose Tissue Activation: Effect of Exercise Training and Irisin

Conditions
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Physical Activity

Intervention / Treatment
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* Other: Exercise


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Healthy sedentary volunteer BMI 20-25 kg/m2 Age: 18-45 years No chronic diseases Exclusion Criteria: BMI < 20 kg/m2 or BMI > 25 kg/m2 Mental disorder or poor compliance Eating disorder or excessive use of alcohol or tobacco smoking Any chronic disease Past dose of radiation Presence of any ferromagnetic objects that would make MR imaging contraindicated Physically disability which rule out the physical fitness tests or participation in the exercise training intervention Any other condition that in the opinion of the investigator could create a hazard to the subject safety, endanger the study procedures or interfere with the interpretation of study results

Ages Eligible for Study
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Minimum Age: 18 Years
Maximum Age: 45 Years

Sexes Eligible for Study
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Male

Accepts Healthy Volunteers
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Accepts Healthy Volunteers

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Basic Science
Intervention Model: Single Group Assignment
Masking: None (Open Label)


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Other: Exercise<br>Arm: Exercise: Combination of moderate intensity continuous training, high intensity interval training and endurance training 5 times per week for a total of 6 weeks. Out of 5 sessions three were supervised by trainer and two sessions were performed by subjects on their own.The duration of the exercise was increased progressively. The first two weeks was 30 minutes that increased to 45 minutes in the third and fourth week. It was 60 minutes for the last two weeks. | Other: Exercise<br> <br> |

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Cold-induced glucose uptake in BAT after exercise | Glucose uptake of brown adipose tissue acquired with PET under cold exposure after exercise intervention. PET imaging is used to quantify glucose uptake in tissues | Within one study day | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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exercise, brown adipose tissue