Pro-coagulant effect of phosphodiesterase exposed to extracellular vesicles, blood cells and endothelial cells in patients with aortic stenosis

Background The mechanism of thrombotic complications in patients with aortic stenosis (AS) is unknown. Our aim was to evaluate the levels of phosphodiesterase (PS) in blood cells, endothelial cells (ECs), and extracellular vesicles (EVs) and its procoagulant activity (PCA) in different degrees of AS. Methods Exposed PS in blood cells, ECs and EVs were analyzed by flow cytometry. PCA was evaluated by clotting time (CT), intrinsic factor Xa (FXa), extrinsic FXa, thrombin and fibrin formation assays. We also evaluated the inhibitory effects of lactadherin (Lact) and anti-tissue factor (anti-TF) on PCA in severe AS patients. Results Our results demonstrated that positive phosphatedylserin (PS+) with total EVs, platelet EVs (PEVs), positive tissue factor EVs (TF+EVs), and endothelial-derived EVs (EEVs) levels were significantly higher in mild to severe AS than controls. Patients with AS had significantly higher percentages of PS+ red blood cells (RBCs), white blood cells (WBCs), platelets (PLTs) and ECs compared to controls. In addition, we further confirmed that PS+ blood cells, ECs and EVs significantly contributed to shortened CT and dramatically increased FXa, thrombin and final fibrin generation in mild to severe AS compared to controls. Furthermore, in severe AS, lactadherin significantly inhibited PCA of PS exposure in blood cells, ECs and EVs, whereas anti-TF had no effect. Conclusion Our study revealed a previously unrecognized association between exposed PS levels on blood cells, ECs and EVs and PCA in AS. Lactadherin promises to be a new therapy by blocking PS to prevent thrombosis in AS patients. ### Competing Interest Statement The authors have declared no competing interest. ### Clinical Trial ChicTR 2200062724 ### Funding Statement This study was funded by Technological Benefits to the Public by Qingdao Municipal Government ### Author Declarations I confirm all relevant ethical guidelines have been followed, and any necessary IRB and/or ethics committee approvals have been obtained. Yes The details of the IRB/oversight body that provided approval or exemption for the research described are given below: IRB of Qingdao Municipal Hospital gave approval for this work I confirm that all necessary patient/participant consent has been obtained and the appropriate institutional forms have been archived, and that any patient/participant/sample identifiers included were not known to anyone (e.g., hospital staff, patients or participants themselves) outside the research group so cannot be used to identify individuals. Yes I understand that all clinical trials and any other prospective interventional studies must be registered with an ICMJE-approved registry, such as ClinicalTrials.gov. I confirm that any such study reported in the manuscript has been registered and the trial registration ID is provided (note: if posting a prospective study registered retrospectively, please provide a statement in the trial ID field explaining why the study was not registered in advance). Yes I have followed all appropriate research reporting guidelines, such as any relevant EQUATOR Network research reporting checklist(s) and other pertinent material, if applicable. Yes All data produced in the present study are available upon reasonable request to the authors