Role of myokines in exercise and metabolism

• Published in: Journal of applied physiology (1985) 2007-09, Vol.103 (3), p.1093-1098
• Main Authors: Pedersen, Bente Klarlund, Akerstrom, Thorbjorn C. A, Nielsen, Anders R, Fischer, Christian P
• Format: Article
• Language: English
• Subjects: Biological and medical sciences; Cytokines; Cytokines - metabolism; Endocrine system; Exercise; Exercise - physiology; Fundamental and applied biological sciences. Psychology; Humans; Interleukin-15 - metabolism; Interleukin-6 - metabolism; Interleukin-8 - metabolism; Metabolism; Muscle, Skeletal - metabolism; Physical fitness
• ISSN: 8750-7587; 1522-1601
• DOI: 10.1152/japplphysiol.00080.2007

Centre of Inflammation and Metabolism, Department of Infectious Diseases and Copenhagen Muscle Research Centre, Rigshospitalet, University of Copenhagen, Faculty of Health Sciences, Denmark During the past 20 yr, it has been well documented that exercise has a profound effect on the immune system. With the discovery that exercise provokes an increase in a number of cytokines, a possible link between skeletal muscle contractile activity and immune changes was established. For most of the last century, researchers sought a link between muscle contraction and humoral changes in the form of an "exercise factor," which could mediate some of the exercise-induced metabolic changes in other organs such as the liver and the adipose tissue. We suggest that cytokines and other peptides that are produced, expressed, and released by muscle fibers and exert either paracrine or endocrine effects should be classified as "myokines." Since the discovery of interleukin (IL)-6 release from contracting skeletal muscle, evidence has accumulated that supports an effect of IL-6 on metabolism. We suggested that muscle-derived IL-6 fulfils the criteria of an exercise factor and that such classes of cytokines should be named "myokines." Interestingly, recent research demonstrates that skeletal muscles can produce and express cytokines belonging to distinctly different families. Thus skeletal muscle has the capacity to express several myokines. To date the list includes IL-6, IL-8, and IL-15, and contractile activity plays a role in regulating the expression of these cytokines in skeletal muscle. The present review focuses on muscle-derived cytokines, their regulation by exercise, and their possible roles in metabolism and skeletal muscle function and it discusses which cytokines should be classified as true myokines. cytokines; interleukins; muscle; physical activity; endocrine Address for reprint requests and other correspondence: B. K. Pedersen, Centre of Inflammation and Metabolism, 7641, Rigshospitalet, Blegdamsvej 9, DK-2100 Copenhagen, Denmark (e-mail: bkp{at}rh.dk )