The Effect of Exercise on Serum Irisin Levels and Clinical Parameters in Patients With Axial Spondyloarthritis.

Axial spondyloarthritis (axSpA) is a chronic inflammatory rheumatic disease affecting young individuals, with a prevalence of 0.3-1.4%. The main features of the disease include inflammatory back pain, reduced joint mobility, and functional disability. In addition, accumulating evidence over recent years has demonstrated that inflammatory rheumatic diseases are associated with an increased risk of cardiovascular disease. Exercise constitutes an important component of the management of inflammatory rheumatic diseases and is widely used to reduce pain and improve joint mobility. Irisin is a myokine secreted by skeletal muscle through the cleavage of the membrane protein fibronectin type III domain-containing protein 5 (FNDC-5). Irisin is considered a mediator of exercise-induced metabolic benefits and has been shown to exert protective effects in several non-metabolic diseases. At the molecular level, irisin contributes to increased energy expenditure and metabolic regulation by promoting the browning of white adipose tissue. Previous studies have demonstrated that serum irisin levels increase following exercise. Studies evaluating the role of irisin in ankylosing spondylitis have reported lower serum irisin levels in patients with more severe disease manifestations. However, no studies investigating the effects of exercise therapy on serum irisin levels in patients with axial spondyloarthritis have been identified in the literature. Previous research has focused on the relationship between disease severity and serum irisin levels, as well as the association between serum irisin levels and cardiovascular disease in patients with ankylosing spondylitis. Overall, low serum irisin levels are thought to be indicative of subclinical atherosclerosis, increased cardiovascular risk, and more severe disease. Evaluating the relationship between serum irisin levels and exercise in patients with axial spondyloarthritis may provide important contributions to disease management and follow-up. Therefore, the present study aimed to investigate the effects of high-intensity intermittent exercise and moderate-intensity continuous exercise on serum irisin levels, disease activity, functional status, and quality of life in patients with axial spondyloarthritis.