The Role Of IL-8 On Neutrophils In STEMI Coronary Thrombosis

Background:Inflammation and oxidative stress play key roles in atherosclerotic plaque instability,and plaque rupture/erosion and subsequent thrombus formation constitute the principal mechanisms of total vessel occlusion and acute ST-elevation myocardial infarction(STEMI).Plaque disruption triggers the formation of initial platelet aggregates that grow in association with an increase in fibrin formation,leading to persistent coronary flow obstruction and thrombosis.IL-8 is a cytokine that has been implicated in the pathogenesis of atherosclerosis and acute coronary syndrome.Elevated plasma levels have been reported in patients with acute myocardial infarction.neutrophil extracellular traps(NETs)play an important role in host defense against infection,but NETs can promote thrombus formation by serving as a scaffold that activates platelets and coagulation.Studies have confirmed the presence of NETs in human venous thrombosis,which can promote venous thrombosis.Therefore,we wondered whether NETs were also present in SETMI coronary thrombosis,Whether elevated serum IL-8 is involved in the formation of NETs in patients with acute myocardial infarctionObjectives:To investigate the presence of NETs in STEMI coronary thrombosis,the correlation between IL-8 in the serum of myocardial infarction and the formation of NETs provides new ideas and directions for antithrombotic therapy of STEMIMethods:Serum and intracoronal thrombus were collected from 30 patients admitted to the department of cardiology of the hospital from May 2018 to October 2019 who received emergency PCI and thrombus aspiration within 12h after onset of STEMI,And peripheral blood of 30 volunteers.The specimens of 19 intracoronal thrombus samples were made into frozen sections and stained with HE staining and immunofluorescence staining.The expression of NETs in serum of STEMI patients and volunteers was determined by ELISA.Neutrophils were isolated from peripheral blood of volunteers,and after 3h of STEMI serum stimulation,the expression levels of NETs were detected by flow cytometry and immunofluorescence staining.After the addition of anti-IL-8 monoclonal antibody to STEMI serum,neutrophils were stimulated and the expression of NETs was observed by flow cytometry.When IL-8 was added to normal serum,neutrophils were stimulated and the expression of NETs was observed by flow cytometry.Results:HE staining of coronary thrombus specimens showed scattered neutrophils in the thrombus,Immunofluorescence staining of thrombus specimens confirmed the presence of NETs in coronary thrombus,The ELISA results showed that the concentration of NETs in serum of STEMI patients was significantly higher than that of volunteers.Human neutrophils were separated by human neutrophils separation kit.After rapid staining with diff,microscopic examination showed that a large number of cells containing segmented nuclei were observed,indicating the successful separation of neutrophils.The neutrophils were cultured in serum medium of 20%STEMI patients for 3h and the supernatant and neutrophils were collected,The collected supernatant was detected by ELISA and the concentration of NETs was significantly increased after STEMI serum stimulation,Neutrophils were detected by immunofluorescence staining and flow cytometry.The results showed that the STEMI serum could stimulate neutrophils to produce NETsAfter the addition of anti-il-8 monoclonal antibody to serum medium of STEMI patients,neutrophils were cultured for 3h,and the neutrophils were collected for flow cytometry detection.The results showed that anti-il-8 antibody could inhibit the production of NETs.After IL-8 was added to normal serum medium,neutrophils were cultured for 3h,and neutrophils were collected for flow cytometry detection.The results showed that IL-8 could promote the production of NETs.Conclusion:Neutrophils and NETs are present in coronary thrombosis,Serum levels of NETs were significantly higher in STEMI patients than in healthy volunteers.Serum IL-8 in STEMI patients is a major factor in stimulating neutrophils to produce NETs,and inhibition of IL-8 significantly reduces the formation of NETs.