[Increased circulating level of fatty acid-binding protein 3 (FABP3): a potential biomarker of muscle damage in inflammatory myopathies patients].

Inflammatory myopathies (IM) are autoimmune diseases characterized by chronic inflammation of skeletal muscle and muscle weakness. Despite immunomodulatory treatments, a high proportion of IM patients who reach low disease activity still suffer sustained disability. This condition, termed "damage", is frequent, and correlates with handicap and mortality. Our study aimed to investigate the association between various myokines imbalance, assessed at the time of inclusion, and the "total damages" in extension and severity, assessed using IMACS (International Myositis Assessment and Clinical Studies) scores, and the "global damage" as assessed by a physician. For this purpose, 40 adult IM patients with disease duration of 12 months or more, low disease activity for at least 6 months, and 30 healthy volunteers (HV) were included. Serum level of fatty acid-binding protein 3 [FABP-3] was 1.8-fold higher in IM patients as compared to HV, and positively correlated with total damage (extension and severity) and global damage scores. Among the IMACS damage domains, the strongest associations were found with gastrointestinal, cardiovascular and muscle scores. In conclusion, increased circulating level of FABP-3 is a candidate biomarker of damage in IM. Knowing the role of FABP-3 in muscle energy metabolism and trophicity, it may also represent an actor of IM damage pathophysiology. Thus, these results may impact the quantification and the development of pharmacological treatment for IM damage.