The Significance of Selected Myokines in Predicting the Length of Rehabilitation of Patients after COVID-19 Infection.

In the context of the global COVID-19 pandemic, understanding the intricate mechanisms of the body's response to infection and inflammation has become a priority for the medical and research communities. It has been proven that during COVID-19 infection, molecules are secreted-namely organokines, which may directly or indirectly play a role in the pathophysiology of COVID-19. The objective of this study was to scrutinize the potential correlation between the levels of selected myokines (myostatin, agrin, irisin, and myonectin) and the duration of rehabilitation in post-COVID-19 patients. Additionally, the study aimed to investigate whether there is a correlation between the levels of these myokines and the length of hospitalization during COVID-19 treatment. The study was conducted at the Rehabilitation Hospital in Szczecin (Poland). Patients in the study participated in a comprehensive rehabilitation program following COVID-19 treatment. In order to assess the effectiveness of rehabilitation, the following tests were performed: a 6 min walk test with an assessment of exercise tolerance (Borg scale), an assessment of dyspnea severity (mMRC scale), a spirometric assessment of respiratory function, a measurement of arm strength, and an assessment of fatigue using the Fatigue Assessment Scale (FAS). Myokine levels were measured using commercially available enzyme-linked immunosorbent assays (ELISA) according to the manufacturer's instructions. Statistical analysis was performed using Statistica 13.1 software. Lower concentrations of irisin and myonectin and higher concentrations of myostatin correlated with longer rehabilitation time. Baseline levels of specific myokines in post-COVID-19 patients could play a crucial role in anticipating the duration of rehabilitation. The duration of hospitalization for the infection may influence myokine levels in patients recovering from COVID-19.