The Rote Of ADAMTS13 In The Progress Of Pancreatic Necrosis In Severe Acute Pancreatitis

Pancreatic necrosis(PN)is one of the most common local complications of acute pancreatitis(AP),and it is also the foundation of subsequent disease progression,which seriously affects the prognosis of AP patients.In recent years,more and more studies have shown that PN may be associated with pancreatic microcirculatory thrombosis.A large number of studies have attempted to elucidate the relationship between von Willebrand factor(vWF)polymer and ADAMTS13(a disintegrin and metalloproteinase with a thrombospondin type 1 motif,member 13)and microcirculatory thrombosis.In particular,UL-VWF(Ultra Large-von Willebrand factor),the active form of vWF,plays a vital role in thrombosis formation and could directly lead to spontaneous platelet adhesion and thrombosis formation.However,UL-VWF can be degraded into small molecules by ADAMTS13 and become a less adherent plasma morphology.Therefore,decreased ADAMTS13 activity is a potential independent risk factor for microcirculatory thrombosis,and vWF is considered as a new potential target for anti-thrombosis therapy.However,there is still lack of relevant research focusing on vWF and ADAMTS13 in AP.Hence,in this study,we aimed to explore the role and underlying mechanism of vWF and ADAMTS13 in the pathogenesis of AP through the following two parts:PART1vWF and AD AMTS 13 in acute pancreatitis:early indicators for pancreatic necrosis and clinical prognosisObjective:To evaluate the relationship between vWF and ADAMTS13 and pancreatic necrosis as well as AP severity by analyzing the distribution of vWF polymers and the activity of ADAMTS13 in AP patients.Methods:All adult AP patients admitted to our hospital within 7 days from November 2018 to January 2019 were included in this study.At admission,the blood samples of the patients were collected,and the relevant clinical data of the patients were collected until discharge.The serum ADAMTS13 activity,vWF and endothelial protein C receptor(EPCR)levels were detected by enzyme-linked immunosorbent assay and agarose gel electrophoresis,and compared with major AP severity indicators to explore the relationship between these indexes and PN and the clinical prognosis of AP.Results:Fifty patients were eventually included in the study,including 20(40%)with severe acute pancreatitis(SAP).Vertical electrophoresis of vWF polymer of plasma of AP patients showed that the content of vWF polymer increased significantly along with the increasing severity of the disease.Especially,UL-vWF,the active form of vWF,was detected in some SAP patients.The activity of ADAMTS13 was negatively correlated with the severity of AP and the computed tomography severity index(CTSI)score.Multivariate logistic regression analysis showed that the decreased ADAMTS13 activity and antithrombin Ⅲ(AT-Ⅲ)were independent risk factors for extensive pancreatic necrosis(pancreatic necrosis extent>30%).The receiver operating characteristic(ROC)curve analysis showed that the area under the ROC curve of ADAMTS13 activity in predicting PN extent>30%was 0.899.Conclusions:ADAMTS13 activity was significantly related to the development of SAP and pancreatic necrosis in AP patients.vWF and its cleaving protein ADAMTS13 may directly participate in the formation of pancreatic microcirculatory thrombosis,thus accelerating the development of PN.PART 2The effects of recombinant AD AMTS13 on mice of severe acute pancreatitis model and mechanism researchObjective:Current studies have shown that vWF and its cleaving protein ADAMTS13 may directly participate in the formation of pancreatic microcirculatory thrombosis,thus accelerating the development of PN.The aim of this study was to explore the mechanism of vWF and ADAMTS13 on pancreatic necrosis by administering recombinant human ADAMTS13(rhADAMTS13)to SAP mice.Methods:Eighteen C57BL/6 mice aged about 8-10 weeks were randomly divided into three groups:Control group,SAP group,SAP+rhADAMTS13(250ug/kg)group,6 mice in each group.SAP model was established by intraperitoneal injection of cerulein combined with lipopolysaccharide.The mice were sacrificed 48 hours after the SAP model induction,and the corresponding blood and tissue samples were collected.The levels of serum amylase,vWF,ADAMTS13 and other related indicators of endothelial injury were detected using blood samples.Pancreatic tissue section was stained with hematoxylin&eosin and fibrin immunohistochemical staining to observe the pathological damage and local microthrombosis formation of pancreratic tissue.Results:The serum levels of ADAMTS13 of mice after SAP induction significantly decreased,and the levels of vWF increased significantly.The polyacrylamide gel electrophoresis showed that UL-vWF appeared in SAP mice.After administration of rhADAMTS 13,UL-vWF disappeared in plasma of SAP mice,accompanied by a significant decrease in vWF expression,and significantly alleviated pancreatic necrosis and reduced pancreatic nicrocirculatory thrombosis in SAP mice.In addition,rhADAMTS13 could also down-regulate the levels of EPCR and P-selectin in plasma of SAP mice,and up-regulate the level of nitric oxide.Western blotting analysis indicated that ADAMTS13 could increase the phosphorylation expressions of Akt and endothelial nitric oxide synthase(eNOS),suggesting that ADAMTS13 might mitigate endothelial injury through activating Akt pathway.Conclusions:Studies have shown that rhADAMTS13 could reduce local microcirculatory thrombosis formation of pancreas by cleaving vWF and reducing endothelial injury,thus reducing pancreatic necrosis.