Ulvan Mediated VE-cadherin Antibody And REDV Peptide Co-modification To Improve Endothelialization Potential Of Decellularized Bioprosthetic Heart Valves

BackgroundCalcified aortic valvular disease(CAVD)is a common valve disease worldwide.As the population ages,the incidence rate is increasing year by year.Currently,there are no especially effective drug therapies to this kind of diseases,and the main treatment for severe aortic stenosis patients is arterial valve replacement(AVR).Bioprosthetic heart valve(BHV)is the most commonly used replacement valve which is mainly made of porcine pericardium.Due to the presence of xenogenic cells in the porcine pericardium and its traditional cross-linking method with certain toxicity,this kind of valves are easily calcification and have poor durability.Decellularization can reduce calcification partially by removal of xenogenic cells,but it also bring new problems such as thrombosis,which raise the necessity of further surface modification.As a natural sulfated polysaccharide,ulvan possesses antithrombotic and anti-inflammatory properties and behaviors as a heparinoid to immobilize proteins through their heparin binding sites.VE cadherin antibody and REDV can facilitate selective endothelial cell attachment,adhesion and proliferation.In this study,we designed a ulvan mediated decellularized biological valve functionally modified with endothelial cell cadherin antibody and REDV polypeptide to promote the endothelialization of the decellularized biological valve and improve its durability.Methods:After the porcine pericardium is decellularized and cross-linked with glutaraldehyde,ulvan is covalently grafted,and then antibodies and polypeptides are grafted through its active groups to prepare a functional decellularized biological valve.Then,XPS,fluorescence,and FTIR were conducted to comfirm successfully modification on valve scaffold.After it,we assessed the affinity of the bioprosthesis to endothelial cells by measuring the adhesion,migration and proliferation of HUVECs,and verified the biocompatibility and antiplatelet ability of the valve scaffolds in vitro via hemolysis test and platelet adhesion test.ELISA assays were conducted to measure the level of inflammatory factors released by RAW macrophages on the surface of the valve to evaluate the anti-inflammatory ability of the valve scaffolds.The anti-calcification ability of the valve scaffold in vitro was evaluated by measuring the calcium content after alternating immersion in the calcificated solution.Rat subcutaneous implantation was conducted to evaluate regeneration and biocompatibility of valve scaffolds in vivo.Results:In the biological valve characterization experiment,FTIR and XPS proved the group changes and the successful grafting of Ulvan on the surface of the biological valve,and the fluorescence imaging proved the successful grafting of antibodies and peptides.In the biological function experiment of the valve scaffolds,we found that compared with the control group(unmodified group),Ulva polysaccharide,REDV polypeptide and VEcadherin antibody modified decellularized biological valve can selectively promote endothelialization in vitro(Adhesion,proliferation and growth of cells(HUVECs)and endothelialization(promoting the infiltration of CD31-positive endothelial cells)in vivo,which can effectively reduce platelet adhesion,anti-calcification in vitro and antiinflammatory in vivo/in vitro.Conclusions:Ulvan,REDV polypeptide and VE-cadherin antibody modified decellularized bioprostheses have good anti-thrombosis,anti-inflammatory and endothelialization potential,and have potential for clinical application.