Promotion of endothelialization of silk functionalized with IKVAV peptide and production of silk containing IKVAV-REDV sequence by transgenic silkworms

Early endothelialization and the prevention of platelet adhesion are crucial in the development of small-diameter vascular grafts to prevent thrombus formation and intimal thickening. Silk fibroin (SF) from Bombyx mori is commonly used for such grafts. In our previous study, we found that silk vascular grafts coated with sponge-like transgenic (TG) silk incorporating the arginine-glutamic acid-aspartate-valine (REDV) peptide and transplanted into rats yielded favorable results. In this study, we aimed to achieve even better results by incorporating additional peptides into TG silk containing REDV and coating silk vascular grafts with this sponge. Initially, we sought to identify such peptides. We attempted to immobilize several peptides containing REDV onto silk using cyanuric chloride. Cell culture experiments with normal human umbilical vein endothelial cells (HUVECs) were performed on SF, SF+REDV, SF + arginine-glycine- aspartate (RGD), SF+cysteine-alanine-glycine (CAG), and SF + isoleucine-lysine- valine- alanine-valine (IKVAV) films to assess adhesion, proliferation, and extensibility; SF+RGD and SF+IKVAV films demonstrated high adhesion behavior of HUVECs. In addition, platelet adhesion on these SF+peptide films was evaluated. Platelet adhesion strength was much higher on SF+RGD films than on other SF+peptide films. These results suggest that IKVAV may be the most suitable peptide for coating SF vascular grafts. Subsequently, we successfully produced TG silk incorporating IKVAV+REDV. We then coated small-diameter silk vascular grafts with sponge-like TG silk incorporating IKVAV+REDV and measured its physical properties.