Downhill running exercise increases circulating level of myokine meteorin-like hormone in humans

Meteorin-like hormone (Metrnl) is a myokine with immunoregulatory traits. This study aimed at evaluating the response of the plasma levels of Metrnl to a downhill running exercise (DHRE) in humans.Twenty active male college students (aged: 22±1.5 years, BMI: 23.50±2.91 kg/m2) completed this study. They performed a skeletal muscle-damaging exercise protocol e.g., downhill running exercise (DHRE) on treadmill. Blood samples were drawn before and after the exercise protocol to measure plasmatic values of Metrnl, eosinophil count, creatine kinase (CK), and lactate dehydrogenase (LDH).Plasma Metrnl level showed a significantly increased level in response to the DHRE (P=0.007). CK (P=0.004), LDH (P=0.001) and the number of plasma eosinophils (P=0.002) also showed significantly increased values following DHRE. Additionally, we found a significant and positive correlation between changes of plasma Metrnl level with those of the number of eosinophils (P<0.05).Downhill running exercise associated with noticeable skeletal muscle damage is accompanied by significantly increased plasma Metrnl level as well as eosinophils' number in sedentary humans.