RESUMEN

Background: Small-diameter vascular grafts have become the focus of attention in tissue engineering. Thrombosis and aneurysmal dilatation are the two major complications of the loss of vascular access after surgery. Therefore, we focused on fabricating 3D printed electrospun vascular grafts loaded with tetramethylpyrazine (TMP) to overcome these limitations. Methods: Based on electrospinning and 3D printing, 3D-printed electrospun vascular grafts loaded with TMP were fabricated. The inner layer of the graft was composed of electrospun poly(L-lactic-co-caprolactone) (PLCL) nanofibers and the outer layer consisted of 3D printed polycaprolactone (PCL) microfibers. The characterization and mechanical properties were tested. The blood compatibility and in vitro cytocompatibility of the grafts were also evaluated. Additionally, rat abdominal aortas were replaced with these 3D-printed electrospun grafts to evaluate their biosafety. Results: Mechanical tests demonstrated that the addition of PCL microfibers could improve the mechanical properties. In vitro experimental data proved that the introduction of TMP effectively inhibited platelet adhesion. Afterwards, rat abdominal aorta was replaced with 3D-printed electrospun grafts. The 3D-printed electrospun graft loaded with TMP showed good biocompatibility and mechanical strength within 6 months and maintained substantial patency without the occurrence of acute thrombosis. Moreover, no obvious aneurysmal dilatation was observed. Conclusions: The study demonstrated that 3D-printed electrospun vascular grafts loaded with TMP may have the potential for injured vascular healing.

RESUMEN

Vascular complications caused by diabetes impair the activities of endothelial nitric oxide synthase (eNOS) and cystathionine γ-lyase (CSE), resulting in decreased physiological levels of nitric oxide (NO) and hydrogen sulfide (H2S). The low bioavailability of NO and H2S hinders the endothelialization of vascular grafts. In this study, endothelium-mimicking bilayer vascular grafts were designed with spatiotemporally controlled dual releases of NO and H2S for in situ endothelialization and angiogenesis. Keratin-based H2S donor was synthesized and electrospun with poly(l-lactide-co-ε-caprolactone) (PLCL) as the outer layer of the graft to release H2S. Hyaluronic acid, one of the major glycosaminoglycans in endothelial glycocalyx, was complexed with Cu ions as the inner layer to mimic glutathione peroxidase (GPx) and maintain long-term physiological NO flux. The synergistic effects of NO and H2S of bilayer grafts selectively promoted the regeneration and migration of human umbilical vascular endothelial cells (HUVECs), while inhibiting the overproliferation of human umbilical artery smooth muscle cells (HUASMCs). Bilayer grafts could effectively prevent vascular calcification, reduce inflammation, and alleviate endothelial dysfunction. The in vivo study in a rat abdominal aorta replacement model for 1 month showed that the graft had a good patency rate and had potential for vascular remodeling in situ.

Asunto(s)

Células Endoteliales , Sulfuro de Hidrógeno , Ratas , Humanos , Animales , Óxido Nítrico/farmacología , Sulfuro de Hidrógeno/farmacología , Prótesis Vascular , Endotelio

RESUMEN

Delayed chest closure (DSC) is widely performed during the treatment of congenital heart diseases. However, the high prevalence of surgical site infection (SSI) in patients undergoing DSC affects prognosis negatively. Herein, we designed a suturable poly (vinyl alcohol)/keratin film loaded with silver nanoparticles (AgNPs) as an alternative material for DSC, which was named PVA/Keratin/AgNPs. The PVA/Keratin/AgNPs films exhibited significantly enhanced mechanical strength after crosslinking by sodium trimetaphosphate (STMP). These films were non-toxic, and cells proliferated with good morphology after 1 week of culture. In addition, PVA/Keratin/AgNPs films provided superior antibacterial ability, as evidenced by the eradication and lower growth rate of Staphylococcus aureus and Escherichia coli. Finally, the PVA/Keratin/AgNPs films were demonstrated to successfully cover the chest cavity temporarily and protect the chest cavity from bacterial infection. These results indicated that the PVA/Keratin/AgNPs films have great prospects to be further exploited for clinical applications in DSC.