Silk fibroin-based vascular repairing sheet with angiogenic-promoting activity of SVVYGLR peptide regenerated the damaged vascular in rats

Medical sheets are useful in surgically repair vascular disease. To avoid long-term side effects, they are to be replaced with regenerated tissue after implantation. Silk fibroin is a fibrous protein secreted by silkworm. The advantage of silk fibroin is its biocompatibility and has been used as regenerative artificial materials. The problem of its biodegradability is that the effect is time consuming. In this study, SVVYGLR peptide was used to expect promoting cell migration and accelerating the biodegradation of silk fibroin. Silk fibroin and polyurethane-based medical sheets with or without SVVYGLR peptide were implanted in rat abdominal aorta (silk fibroin/polyurethane/SVVYGLR peptide versus silk fibroin/polyurethane). The result of histological evaluation indicated that the new cell layer created under both sheets was composed of endothelial cells, smooth muscle, and fibroin in both sheets and similar to a native vessel. Both sheets did not show any excessive inflammation or calcification, and moderate biodegradability was observed. The decrease of silk fibroin indicated the biodegradability of all sheets. Silk fibroin/polyurethane/SVVYGLR peptide had many small vessels in the regenerated tissue than silk fibroin/polyurethane. This appearance indicated that SVVYGLR peptide promoted the angiogenesis in the regenerative tissue. This study suggested that SVVYGLR peptide could give the angiogenic-promoting activity to silk fibroin-based vascular repairing sheet.