NETs and active caspase-1 colocalize both in vitro and in vivo, and inhibition of caspase-1 reduces DVT. (A) Immunofluorescent staining for activated caspase-1 on NETs formed by human neutrophils stimulated with either PMA or glucose oxidase (FLICA, green; ASC, red; myeloperoxidase, blue). Scale bar = 15 μm. Quantification of the percentage of active caspase-1–containing cells that simultaneously release NETs (B) and the percentage of NETotic cells containing active caspase-1 (C) (n = 3). (D) Z-projection of the murine IVC wall 2 hours after stenosis obtained by intravital microscopy (FLICA/active caspase-1, green; SYTOX Orange, red; CD41, blue). Asterisk depicts the site of stenosis; arrow shows the direction of blood flow. Scale bar = 100 μm, n = 3. (E) Thrombus weight and length, and thrombosis incidence in ac-yvad-cmk (n = 12) and vehicle control-treated mice (n = 12). **P ≤ .01; weight and length, Mann-Whitney U test; incidence, Fisher’s exact test. (F) Citrullinated histone 3 (green) and DNA (blue) immunofluorescence staining of control thrombi and of thrombi developed in mice treated with ac-yvad-cmk. Scale bar = 25 μm, n = 4.