Novel Biomarkers for Ankylosing Spondylitis through Proteomic Profiling of Serum-Derived Extracellular Vesicles

The objective of this study is to analyze the protein composition of extracellular vesicles (EVs) isolated from the serum of ankylosing spondylitis (AS) patients to identify potential biomarkers that could enable the early diagnosis and intervention of this condition. Serum samples were collected from AS patients and healthy controls. EVs were isolated from these samples using ExoQuick® ULTRA solution, and their morphology, size, and concentration were analyzed using transmission electron microscopy and nanoparticle tracking analysis. Proteins within the EVs were identified and quantified through liquid chromatography-mass spectrometry (LC-MS/MS), followed by validation of key proteins using enzyme-linked immunosorbent assay (ELISA). Data were analyzed to identify proteins significantly upregulated in AS patients compared with the levels in controls. Here, through LC-MS/MS analysis, we demonstrated that FBLN1, VWF, CFHR2, and LYZ expression were significantly upregulated in serum-derived EVs from AS patients compared with the levels in healthy controls. These findings were further validated by ELISA, confirming the potential utility of serum-derived EVs as specific biomarkers for AS. The elevated levels of FBLN1, VWF, CFHR2, and LYZ in the EVs of AS patients represent promising candidates for biomarkers in the early diagnosis and treatment of AS. Further research should be performed to validate these findings and explore their clinical applicability.