A small-diameter vascular graft promotes rapid and benign remodeling of the neointima through dual release of nitric oxide and hydrogen sulfide

Coronary artery bypass grafting often requires autologous veins as alternatives. The limited source and problem of over-expansion are major obstacles for vein grafts, which could be solved by small-diameter artificial vascular graft. However, their clinical application is limited by thrombosis and restenosis caused by incomplete endothelialization and abnormal smooth muscle cells (SMCs) proliferation. Nitric oxide (NO) and hydrogen sulfide (H2S) are crucial signaling molecules in the cardiovascular system, known to regulate endothelial cells(ECs) and SMCs proliferation, migration, reduce oxidative stress, and inhibit inflammation to prevent intimal hyperplasia. In this study, we developed a new method to prepare a keratin based H2S donor(KAT) complexed with copper ions and electrospun it with PCL to prepare PCL/KAT-Cu small-diameter tissue-engineered vascular graft, which is capable of dual release of NO and H2S. We investigated the effects of NO and H2S release on human umbilical vein endothelial cells (HUVECs) and human umbilical arterial smooth muscle cells(HUASMCs) proliferation and migration, evaluated the graft's selectivity for HUVECs, and assessed its effects on macrophage phenotypic transitions and its protective effect on HUVECs under reactive oxygen species (ROS) conditions. Additionally, we tested the graft's ability to rapidly endothelialize under shear force using an in vitro 3D-perfusion system. After one month of in situ transplantation in rat abdominal aorta, the PCL/KAT-Cu small-diameter tissue-engineered vascular grafts demonstrated satisfactory intimal remodeling, comparable to natural blood vessels. In conclusion, our study presents a promising new strategy for remodeling small-diameter vascular grafts.