Phosphotidylserine exposure and neutrophil extracellular traps enhance procoagulant activity in patients with inflammatory bowel disease

Abstract

Inflammatory bowel disease (IBD)-associated thromboembolic event often lacks precise aetiology. The aim of this study was to investigate the contribution of phosphatidylserine (PS) exposure and neutrophil extracellular traps (NETs) towards the hypercoagulable state in IBD. We demonstrated that the levels of PS exposed MPs and the sources of MP-origin, platelets, erythrocytes, leukocytes and cultured endothelial cells (ECs) were higher in IBD groups than in healthy controls using flow cytometry and confocal microscopy. Wright-Giemsa and immunofluorescence staining demonstrated that the elevated NETs were released by activated IBD neutrophils or by control neutrophils treated with IBD sera obtained from patients with the active disease. MPs and MP-origin cells in IBD groups, especially in active stage, markedly shortened coagulation time and had increased levels of fibrin, thrombin and FXa production as assessed by coagulation function assays. Importantly, we found that on stimulated ECs, PS rich membranes provided binding sites for FXa and FVa, promoting fibrin formation while TNF blockage or IgG depletion attenuated this effect. Treatment of control neutrophils with TNF and isolated IgG from PR3-ANCA-positive active IBD patients also resulted in the release of NETs. Blockade of PS with lactadherin prolonged coagulation time, decreased fibrin formation to control levels, and inhibited the procoagulant enzymes production in the MPs and MP-origin cells. NET cleavage by DNase I partly decreased PCA in IBD or stimulated neutrophils. Our study reveals a previously unrecognised link between hypercoagulable state and PS exposure or NETs, and may further explain the epidemiological association of thrombosis within IBD patients.

The Dual Role of Neutrophils in Inflammatory Bowel Diseases

“…Recently, it has been demonstrated that neutrophils from IBD patients release more NETs than controls [149]. The authors propose that NETs, and also the elevated phosphatidylserine (PS) exposure on MPs from different cell origins, could be the link between IBD and the hypercoagulable state observed in these conditions.…”

“…ANCAs can indeed be directed against NET components, such as MPO, NE, cathespin G or proteinase 3. Thus, as also observed in systemic lupus erythematous (SLE), ANCAs may trigger the release of NETs from neutrophils and participate in the amplification of ANCA generation by exposing new antigenic proteins [149,151]. …”

Intercellular Interactions as Regulators of NETosis

“…The role of MP in promoting NETosis was also demonstrated in a paper focusing on preeclampsia, in which placenta syncytiotrophoblast-derived MP seem to promote NETosis (117). In inflammatory bowel disease, MP also appear to activate NETosis (118). …”

NETopathies? Unraveling the Dark Side of Old Diseases through Neutrophils

“…Cells of the hematopoietic system, including neutrophils, platelets, and monocytes, have a major role in this process (64). There is increasing evidence implicating NET release with the development of both vein and arterial thrombosis (12, 14, 16, 26, 65, 70–77). Extracellular deposition of DNA co-localized with neutrophil granule proteins has been shown in thrombi from patients with deep vein thrombosis (DVT) (78), especially at the phase of organization of the thrombus (70).…”

“…Besides their role in infectious disorders, studies carried out after 2008 support the role of NETs in the pathophysiology of non-infectious diseases, such as thrombosis (12–16), autoimmune diseases (14, 17–22), genetically driven autoinflammatory (23), and other inflammation-related diseases (24–26), metabolic disorders (27, 28), lung diseases (29–32), fibrosis (33), and cancer (34–36). …”