Extracellular Vesicles Derived from Ligament Tissue Transport Interleukin‐17A to Mediate Ligament‐To‐Bone Crosstalk in Ankylosing Spondylitis (Adv. Sci. 46/2024)

Pathological New Bone Formation in Ankylosing Spondylitis In article number 2406876, Kaiyang Wang, Yong Qiu, Bang-Ping Qian, and co-workers present a novel mechanism for pathological new bone formation in ankylosing spondylitis (AS). The cover image depicts the spine at the site of this abnormal new bone formation, highlighting the role of extracellular vesicles (EVs) derived from ligament tissue. These EVs, shown in blue, are visualized as attracting stem cells, represented in yellow, to the ligament tissue. A swirling mass of EVs forms a “tornado,” pulling stem cells from surrounding areas to the ligament, where they differentiate into bone cells, ultimately contributing to the formation of pathological new bone in AS.