HMGB1 and triple-A syndrome: While macrophages play a key role in AAA formation through HMGB1 production [153], single-cell RNA sequencing (scRNA-seq) revealed that HMGB1 is highly enriched in adipocyte, neurons, mesothelial cells (form a thin protective layer called “mesothelium”, covering the whole serous cavities and the entire surface of internal organs), and VSMC within the AAA aorta [154].