Proteomic Profiling of Serum-Derived Extracellular Vesicles in Diffuse Idiopathic Skeletal Hyperostosis Patients

This study focuses on the proteomic profiles of serum-derived EVs in diffuse idiopathic skeletal hyperostosis (DISH), aiming to identify the potential diagnostic biomarkers for DISH. Serum-EVs were separated using a differential centrifugation technique. Then, label-free-liquid chromatography mass spectrometry (LC-MS/MS) was utilized to identify differentially expressed proteins (DEPs) highly associated with DISH. DEPs' expression levels were tested using enzyme-linked immunosorbent assay (ELISA) and bioinformatic analyses were performed. According to ectopic ossification severity, DISH cohort was stratified into T-DISH and L-DISH subtypes. Serum-EVs' AHSG level was also compared between T-DISH and L-DISH subgroups. Additionally, the number of ossified segments of all DISH patients was assessed and its correlation with serum-EVs' AHSG was analyzed. LC-MS/MS proteomic analyses demonstrated 24 up-regulated and 6 down-regulated proteins in the DISH group. ELISA results showed that AHSG level in serum-EVs was significantly higher in the DISH group. Interestingly, serum-EVs' AHSG was found significantly higher in the L-DISH subgroup compared to the T-DISH subgroup and a strong positive correlation was demonstrated between the quantified ossified segments and serum-EVs' AHSG. Hence, serum-EVs' AHSG may be a promising biomarker for DISH and participate in the pathogenesis of heterotopic bone formation in DISH.