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

Wageningen University12 enrolled

Overview

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.

Study Type

INTERVENTIONAL

Allocation

Purpose

BASIC_SCIENCE

Masking

NONE

Enrollment

Conditions

Exercise Muscle

Eligibility

Sex: MALEMin age: 40 YearsMax age: 60 YearsHealthy volunteers:

Medical Language ↔ Plain English

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

Outcomes

Primary Outcomes

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.

Time frame: 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)

Time frame: T = 0, T =1 and T = 3

Secondary Outcomes

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.

Time frame: 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.

Time frame: 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.

Time frame: During the intervention