Circumferentially Aligned Electrospun Vascular Grafts Improves Its Vascular Regeneration and Remodeling in vivo.

Introduction: Despite the rapid development of small diameter vascular graft (SDVG), the ability of synthetic grafts to facilitate tissue remodeling and regeneration remains an important challenge within regenerative medicine. Methods: Based on our previous research work, silk fibroin (SF)/fibrin vascular grafts were successfully fabricated using electrospinning technology, and it was demonstrated that the grafts had superior mechanical strength, good cytocompatibility and histocompatibility. This indicated that the vascular graft was an ideal SDVG. We developed SF/fibrin vascular grafts with circumferentially aligned nanofibers to explore some of its properties in vivo. Results: The graft exhibited randomly arranged microstructure, excellent mechanical properties and compliance properties. These vascular grafts were transplanted into the abdominal aorta of rats, maintaining normal blood flow, vascular patency, and functionality. The M2/M1 ratio value in SF/fibrin grafts increased over time after implantation. Whereas the expression level of inflammatory cytokines initially increased and then eventually reached the normal levels. Moreover, the circumferentially aligned vascular grafts could guide the regeneration of neoarteries, endothelialization formation, enhanced functionality, rapid cellular infiltration and improved extracellular matrix (ECM) deposition, as well as generated more microvessels and fewer calcification. Discussion: Our research focused on the long-term performance in vivo of SF/fibrin tubular grafts, which could become a new type of SDVG and help guide the development of next-generation vascular grafts.