MyoGene: Effects of Acute Exercise on (Myokine) Gene Expression in Human Skeletal Muscle

Study Overview
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Brief Summary
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Rationale: Proteins released from muscle during and shortly after exercise, often referred to as myokines, may be central to our understanding of the cross-talk during and after exercise between skeletal muscles and other organs, in particular the liver. So far only a few myokines are identified (e.g. IL-6, IL-8, IL-15, TNF-alpha). Taking into account the role of these several known myokines in developing insulin resistance, revealing new putative myokines might provide valuable information and a direction for future research on the pathogenesis and treatment of type 2 diabetes mellitus. Objective: The objective of the present study is to identify novel myokines, expression of which is altered in skeletal muscle after a single bout of exercise. Study design: experimental study. Study population: Ten healthy, male subjects between 40 and 60 years of age and BMI < 30 kg/m2, will participate in this study. Intervention: A single exercise bout that consists of one hour one-legged cycling on a adapted recumbent cycle ergometer at a submaximal rate. The non-exercising leg will serve as control for the exercising leg. Main study outcomes: Main study outcomes include upregulation of genes in skeletal muscle after exercise (with a focus on genes encoding myokines) and changes of blood plasma levels of selected proteins after exercise.

Official Title
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Effects of Acute Exercise on (Myokine) Gene Expression in Human Skeletal Muscle

Conditions
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Muscle, Exercise, Gene Expression, Myokine

Intervention / Treatment
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* Other: Single legged exercise


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Age 40-60 years Male gender BMI < 30 kg/m2 Exclusion Criteria: Exercising regularly (> 2 times a week, > 3 hour in total per week) Unstable body weight (weight gain or loss > 3 kg in the past three months) Following, or have recently followed a (weight-loss) diet Donated or intended to donate blood 2 months before until two months after the study Medical condition that can interfere with the study outcome (i.e. cardiovascular disease, pulmonary disease) Systolic blood pressure >160 mmHg and/or diastolic blood pressure >100 mmHg Use of medications known to interfere with gene expression in the muscles (i.e. statins, fenofibrate). Use of antithrombotic therapy (marcoumar, sintromitis). Diagnosed diabetes mellitus type 1 or 2. Drugs or alcohol abuse ( > 3 glasses of alcoholic beverages a day). (Chronic) injuries of the locomotor system that can interfere with the intervention Participated in another study within the last six months

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 60 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 |
| --- | --- |
| Experimental: Exercise<br> | Other: Single legged exercise<br>* A single exercise bout that consists of one hour one-legged cycling on a adapted recumbent cycle ergometer at a submaximal rate. The non-exercising leg will serve as control for the exercising leg.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Gene expression changes in skeletal muscle from baseline to after exercise | Gene expression is measured using whole genome Affymatrix microarrays Muscle tissue will be collected at time points T = 0 (before exercise) and T = 1 (directly after exercise). Special focus is on the changes in genes coding for myokines. Up to 5 genes will be selected for follow-up analysis. | T = 0 and T =1 | 
| Changes in plasma levels of selected proteins | Selected proteins will be analyzed by ELISA assays or western blot analysis, depending on ELISA availability at T = 0, T = 1 and T = 3 (2 hours post-exercise). The selection of the proteins is based on significance, the robustness of induction (>80% of subjects showing induction) and the magnitude of the induction ( mean fold change > 2) | T = 0, T =1 and T = 3 | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| PBMC gene expression changes before and after exercise | Gene expression changes in the blood will be assessed using whole genome Affymetrix microarrays for the samples at T = 0, 1 and 3. | T = 0, T = 1 and T =3 | 
| Routine plasma level changes before and after exercise | At all three time point (T = 0, 1 and 3) plasma levels of glucose, insulin, fatty acids, triglycerides, cortisol, adrenalin and lactate will be determined. | T = 0, 1 and 3 | 
| Heart rate changes, baseline compared with exercise | Heart rate will be measured during the maximum work load test and the experimental exercise period. | During the intervention |