A Small-Diameter Artificial Vascular Graft: Biocompatibility Evaluation and Regulatory Mechanisms of Vascular Remodeling at the Cellular and Molecular Levels

The increasing prevalence of cardiovascular diseases highlights the urgent demand for small-diameter artificial vascular grafts (SD-AVGs). However, the clinical application of current SD-AVGs is limited by complications such as thrombosis and proliferative stenosis. We first designed and fabricated a triple-layered SD-AVG (TL-SD-AVG) composed of polycarbonate polyurethane and polyethylene terephthalate using electrospinning and mixed weaving techniques. Then, we characterized its mechanical properties through standard mechanical testing. Cytotoxicity, cell adhesion assay hemolysis, and blood clotting assays were subsequently performed to preliminarily evaluate its cytocompatibility and hemocompatibility in vitro. Next, we assessed the TL-SD-AVG's tissue compatibility and biosafety using a porcine carotid artery replacement model. Finally, we employed both bulk RNA sequencing (RNA-seq) and single-nucleus RNA sequencing (snRNA-seq) to investigate the cellular and molecular mechanisms involved in vascular remodeling. Our results showed that the TL-SD-AVG exhibited adequate mechanical strength, low cytotoxicity, and a hemolysis rate below 5%, and its anticoagulant performance was better than the expanded polytetrafluoroethylene control graft. In vivo, the grafts maintained structural integrity and patency over a 4-week period, with no thrombus formation or pathological stenosis. Histopathological analyses revealed endothelial coverage of 34.66 ± 4.47% at 1 week, increasing to 72.14 ± 4.01% by 4 weeks. RNA-seq and snRNA-seq identified six key cell types involved in vascular regeneration, with no significant aberrations in pathways related to vascular remodeling. Both in vitro and in vivo experiments demonstrated that TL-SD-AVG had low cytotoxicity, good hemocompatibility, favorable histocompatibility, and overall biosafety. Moreover, it supported effective vascular remodeling, providing a robust theoretical and experimental foundation for its future clinical translation.