Released during necrosis, apoptosis, and neutrophil extracellular trap (NET) formation, histones act as damage-associated molecular patterns (DAMPs), engaging receptors such as Toll-like receptors (TLR2, TLR4, TLR9) to trigger endothelial dysfunction, platelet activation, and cytokine release. Here, TLR9 is linked to endothelial dysfunction.