Tao Li1,2, Chunxu Wang1, Yingmiao Liu3, Baorong Li3, Wujian Zhang4, Lixiu Wang5, Muxin Yu1, Xinyi Zhao6, Jingwen Du1, Jinming Zhang7, Zengxiang Dong5, Tao Jiang4, Rui Xie8, Ruishuang Ma8, Shaohong Fang2, Jin Zhou1, Jialan Shi1,9. 1. Department of Hematology, the First Hospital, Harbin Medical University, Nangang District, Harbin, PR, China. 2. Key Laboratory of Myocardial Ischemia, Ministry of Education, Heilongjiang, China. 3. Department of Stomatology of the First Affiliated Hospital, Harbin Medical University, Heilongjiang, China. 4. Department of General Surgery of the First Hospital, Harbin Medical University, Heilongjiang, China. 5. Department of Cardiology of the First Affiliated Hospital, Harbin Medical University, Heilongjiang, China. 6. Department of Cardiology of the Second Affiliated Hospital, Harbin Medical University, Heilongjiang, China. 7. Department of Gastroenterology of the Fourth Affiliated Hospital, Harbin Medical University, Heilongjiang, China. 8. Department of Oncology of The Third Hospital, Harbin Medical University, Heilongjiang, China. 9. Medicine Departments of Surgery, Brigham and Women's Hospital, VA Boston Healthcare System and Harvard Medical School, Boston, MA, USA.
Abstract
BACKGROUND AND AIMS: Despite the presence of neutrophil extracellular traps [NETs] in inflamed colon having been confirmed, the role of NETs, especially the circulating NETs, in the progression and thrombotic tendency of inflammatory bowel disease [IBD] remains elusive. We extended our previous study to prove that NETs constitute a central component in the progression and prothrombotic state of IBD. METHODS: In all 48 consecutive patients with IBD were studied. Acute colitis was induced by the treatment of C57BL/6 mice with 3.5% dextran sulphate sodium [DSS] in drinking water for 6 days. Peripheral blood neutrophils and sera were collected from IBD patients and murine colitis models. Exposed phosphatidylserine [PS] was analysed with flow cytometry and confocal microscopy. Procoagulant activity was evaluated using clotting time, purified coagulation complex, and fibrin formation assays. RESULTS: We observed higher plasma NET levels and presence of NETs in colon tissue in patients with active IBD. More importantly, NETs were induced in mice with DSS colitis, and inhibition of NET release attenuated colitis as well as colitis-associated tumorigenesis. NET degradation through DNase administration decreased cytokine levels during DSS-induced colitis. In addition, DNase treatment also significantly attenuated the accelerated thrombus formation and platelet activation observed in DSS-induced colitis. NETs triggered PS-positive microparticle release and PS exposure on platelets and endothelial cells partially through TLR2 and TLR4, converting them to a procoagulant phenotype. CONCLUSIONS: NETs exacerbate colon tissue damage and drive thrombotic tendency during active IBD. Strategies directed against NET formation may offer a potential therapeutic approach for the treatment of IBD.
BACKGROUND AND AIMS: Despite the presence of neutrophil extracellular traps [NETs] in inflamed colon having been confirmed, the role of NETs, especially the circulating NETs, in the progression and thrombotic tendency of inflammatory bowel disease [IBD] remains elusive. We extended our previous study to prove that NETs constitute a central component in the progression and prothrombotic state of IBD. METHODS: In all 48 consecutive patients with IBD were studied. Acute colitis was induced by the treatment of C57BL/6 mice with 3.5% dextran sulphate sodium [DSS] in drinking water for 6 days. Peripheral blood neutrophils and sera were collected from IBDpatients and murinecolitis models. Exposed phosphatidylserine [PS] was analysed with flow cytometry and confocal microscopy. Procoagulant activity was evaluated using clotting time, purified coagulation complex, and fibrin formation assays. RESULTS: We observed higher plasma NET levels and presence of NETs in colon tissue in patients with active IBD. More importantly, NETs were induced in mice with DSS colitis, and inhibition of NET release attenuated colitis as well as colitis-associated tumorigenesis. NET degradation through DNase administration decreased cytokine levels during DSS-induced colitis. In addition, DNase treatment also significantly attenuated the accelerated thrombus formation and platelet activation observed in DSS-induced colitis. NETs triggered PS-positive microparticle release and PS exposure on platelets and endothelial cells partially through TLR2 and TLR4, converting them to a procoagulant phenotype. CONCLUSIONS: NETs exacerbate colon tissue damage and drive thrombotic tendency during active IBD. Strategies directed against NET formation may offer a potential therapeutic approach for the treatment of IBD.