Myokines are small proteins produced and released by skeletal muscle cells, specifically in response to muscular contractions. These proteins act as signaling molecules, allowing muscles to communicate with various other organs throughout the body. Their general role involves influencing a wide range of physiological processes beyond just muscle movement.
Muscles as Endocrine Organs
The understanding of muscles has evolved from viewing them solely as mechanical movers to recognizing them as active endocrine organs. This shift in perspective highlights the ability of muscles to produce and secrete substances that exert effects on distant tissues and organs. Myokines serve as the primary messengers in this systemic communication, linking muscle activity to the health and function of the entire body.
Myokines Impact on Body Systems
Myokines play diverse physiological roles across various body systems, contributing significantly to overall health. Regarding metabolic health, myokines like Interleukin-6 (IL-6) enhance glucose uptake and lipolysis, which is the breakdown of fats. Irisin, another myokine, helps improve insulin sensitivity and promotes the “browning” of white fat cells, increasing energy expenditure. Myokines also regulate lipid metabolism and can help prevent fat accumulation in the liver.
In the brain, myokines influence neurogenesis, which is the formation of new neurons, and support cognitive function. Brain-derived neurotrophic factor (BDNF), a myokine, is important for promoting neuron growth and maintenance, supporting neuroplasticity, memory, and learning. Myokines may also offer protection against neurodegenerative diseases like Alzheimer’s and Parkinson’s disease.
Myokines contribute to immune regulation through their anti-inflammatory effects. For instance, IL-6 acts as an anti-inflammatory myokine, reducing chronic inflammation. This modulation of immune responses helps the body maintain a balanced inflammatory state.
Concerning bone health, myokines influence bone density and remodeling. Myostatin, a myokine, also affects bone remodeling by accelerating osteoclast formation, which are cells that break down bone. Irisin also plays a role in bone maintenance by modulating osteogenesis-stimulating factors.
Myokines contribute to cardiovascular health by supporting heart function and vascular health. For example, Follistatin-like 1 (FSTL1) is associated with improved vascular health and function. Myokines like myostatin are also being investigated for their role in cardiac conditions such as heart failure, where increased levels are often observed.
Myokines also show potential anti-cancer effects. They can suppress tumor growth and metastasis by influencing cancer cell proliferation, apoptosis, and the tumor microenvironment. Studies have shown that a single session of exercise can elevate anti-cancer myokines, suppressing tumor growth.
Boosting Myokines Through Exercise
Physical activity is a primary stimulus for myokine production and release. Different types of exercise, including endurance and resistance training, can stimulate the release of various myokines. For example, running may lead to a greater release of IL-6 compared to cycling.
Resistance training is effective in enhancing myokine release, contributing to maintaining and gaining muscle mass and strength. Regular movement is linked to myokine activity, highlighting its importance for overall health benefits. The specific myokines released can vary depending on the mode and intensity of the exercise.
Therapeutic Potential of Myokines
Ongoing research explores the potential of myokines as therapeutic targets for chronic diseases. By understanding how myokines communicate with different organs, scientists aim to develop new treatments that harness or mimic their actions. This could lead to novel pharmacological approaches for conditions like type 2 diabetes, where myokines have shown promise in improving insulin sensitivity and adipose tissue function. Myokines are also being investigated for their role in alleviating muscle wasting associated with various diseases and aging.