Small-diameter hybrid vascular grafts composed of polycaprolactone and polydioxanone fibers

Yiwa Pan,Yongzhen Wei,Deling Kong,Wen Li,Qiuying Zhang,Meifeng Zhu,Qiang Zhao,Guanwei Fan,Rui Huang,Ting Wang,Jingrui Chen,Kai Wang,Ruming Liu,Xin Zhou

doi:10.1038/s41598-017-03851-1

Yiwa Pan, Yongzhen Wei + Show 12 more

Open Access

https://doi.org/10.1038/s41598-017-03851-1

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Abstract

Electrospun polycaprolactone (PCL) vascular grafts showed good mechanical properties and patency. However, the slow degradation of PCL limited vascular regeneration in the graft. Polydioxanone (PDS) is a biodegradable polymer with high mechanical strength and moderate degradation rate in vivo. In this study, a small-diameter hybrid vascular graft was prepared by co-electrospinning PCL and PDS fibers. The incorporation of PDS improves mechanical properties, hydrophilicity of the hybrid grafts compared to PCL grafts. The in vitro/vivo degradation assay showed that PDS fibers completely degraded within 12 weeks, which resulted in the increased pore size of PCL/PDS grafts. The healing characteristics of the hybrid grafts were evaluated by implantation in rat abdominal aorta replacement model for 1 and 3 months. Color Doppler ultrasound demonstrated PCL/PDS grafts had good patency, and did not show aneurysmal dilatation. Immunofluorescence staining showed the coverage of endothelial cells (ECs) was significantly enhanced in PCL/PDS grafts due to the improved surface hydrophilicity. The degradation of PDS fibers provided extra space, which facilitated vascular smooth muscle regeneration within PCL/PDS grafts. These results suggest that the hybrid PCL/PDS graft may be a promising candidate for the small-diameter vascular grafts.

Highlights

Electrospun polycaprolactone (PCL) vascular grafts showed good mechanical properties and patency
The grafts have much better effects in vascular regeneration and remodeling compared to thin fiber PCL grafts, the slow degradation of PCL is still a problem
We planned to fabricate a series of vascular grafts over a wide range of ratios by adjusting electrospun PDS parameters (Table S1)

Summary

Results and Discussion

The optimized PCL fibers were selected to prepared PCL/PDS vascular grafts. After completely leaching PCL, the hybrid graft still maintained a good tubular structure (Supplementary Fig. S1), which indicated that the distribution of the two kinds of fibers was randomly and uniformly. After the incorporation of hydrophilic PDS component (11.54 ± 0.60°), the hydrophicity was improved, that is, the mean WCA of PCL/PDS decreased to 78.06 ± 2.20° (Fig. 1E) This was in agreement with our previous study that co-electrospun PCL and hydrophilic gelatin increased the hydrophicity of hybrid scaffolds[19]. The mechanical properties of PCL/PDS grafts were further lowered with increasing implantation time, and they were very close to native abdominal aorta without significant difference after 3 months (Supplementary Fig. S9). Evaluation of the patency and luminal diameter of explanted grafts at 3 months after implantation. (A) The patency was measured by color Doppler ultrasound. (B) The patency rates of the PCL and PCL/ PDS grafts at both time points. (C) The lumen of the explanted grafts was smooth and free of thrombus under stereomicroscope. (D) Cross sections were stained with H&E to identify the neointima formation. (E) Representative H&E staining of longitudinal sections of explanted grafts. (F) The luminal diameter of explanted grafts was calculated based on the cross sections with H&E staining. (L) lumen; Red arrows: suture site. *p < 0.05

Abdominal aorta

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