Dynamic changes of systemic and local myokines in burn patients undergoing physiotherapy: A pilot prospective study

Myokines, important signalling molecules in regulation of homeostasis in a post-injury state, have not been studied in burn patients. Here, we aimed to analyse dynamic changes in systemic and local concentrations of myokines and evaluated their associations with the mode of physiotherapy in burn patients. In this pilot study, 20 burn patients underwent repeated functional proprioceptive stimulation and conventional physiotherapy. Plasma, skeletal muscle, and fatty tissue biopsies were obtained before and after physiotherapy and selected myokines were analysed by multiplex assays. There was no significant difference in myokine expression in relation to the mode of physiotherapy (p > 0.05); both modes were associated with a pattern of decreasing brain-derived neurotrophic factor (BDNF) plasma concentrations immediately after exercise. While BDNF plasma concentrations and follistatin-like 1 (FSTL1) muscle concentrations significantly increased over the 40-day post-injury hospitalization, plasma concentrations of FSTL1, fatty acid-binding protein 3 (FABP3), and interleukin 6 (IL6) decreased. In addition, FSTL1 in skeletal muscle increased during hospitalization in burn patients regardless of the physiotherapy mode. Significant positive correlations among FABP3, FSTL1, and IL6 in plasma were observed (r > 0.55); moreover, BDNF plasma concentrations significantly negatively correlated with those of FABP3 and FSTL1 (r = -0.53 and -0.45, respectively). In conclusion, we have identified a range of myokines potentially associated with rehabilitation and recovery in burn injury patients, which could help in further study of muscle wasting prevention in critically ill patients. We demonstrated the suitability of the panel for studying dynamic changes in concentrations of multiple myokines. BDNF, FABP3, and FSTL1 were shown to be the most promising myokines for further research in this area.