State-of-the-art insights into myokines as biomarkers of sarcopenia: a literature review

Sarcopenia is an age-associated progressive deterioration of skeletal muscle, not only affecting the muscle function of elderly individuals but also contributing to various health issues and increased mortality. Current diagnostic tools are faced with limitations, hindering their widespread clinical application. This review examines the potential of myokines, peptides released from contracting muscles, as innovative biomarkers for sarcopenia. We explore the wide range of auto-, para-, and endocrine functions of myokines and the pathways of their physiological action, as well as address ongoing research results on the role of myokines as biomarkers for the timely diagnosis of sarcopenic individuals. Of all myokines, the ones that show the highest potential include irisin, myostatin, follistatin and brain-derived neurotrophic factor (BDNF). Their physiological action is exerted through complex pathways involving multiple molecules. Most studies show that these molecules can be used as biomarkers for the timely diagnosis of sarcopenia, whether by using each one individually or as a panel of biomarkers. However, several studies showed no correlation between the plasma levels of these peptides and a sarcopenia diagnosis. Finally, a number of studies also exhibited gender-affected relationships. While the quality of studies is promising, research on the use of myokines as biomarkers of sarcopenia is needed to more accurately determine the cut-off plasma values of such markers. By overcoming the shortcomings of existing methodologies, utilizing myokines in daily clinical practice could offer a promising path toward more effective prevention, diagnosis, and treatment strategies, ultimately improving outcomes for the aging population.