A Prevascularization Strategy Using Novel Fibrous Porous Silk Scaffolds for Tissue Regeneration in Mice with Spinal Cord Injury

Spinal cord injury (SCI) represents an extremely debilitating condition for which no efficacious treatment is available. Because spinal cord does not have satisfactory capacity for revascularization after injury, it seems to be a promising way to modulate the lesion environment by reperfusion to promote a regenerative phenotype. Although engineered scaffolds provide a platform to deliver therapeutic cells and neurotrophic factors, slow and insufficient vascularization of large tissue constructs negatively impacts the survival and function of these transplanted cells. In this study, we cocultured our fibrous porous silk scaffold (FPSS) with ADAMTS13-overexpressing human umbilical vein endothelial cells (HUVECs) in vitro and transplanted this prevascularized construct into an SCI mouse model. The prevascularized system exhibited a tube-like structure in vitro, promoted vascular infiltration and microvascular network formation after transplantation, and recruited more neural cells to the lesion site. Twenty-eight days later, behavioral analysis showed that locomotor recovery was significantly improved in treated animals compared with control animals. Taken together, our results suggest that the FPSS-HUVECs system promoted neovascularization, guided axon growth at the injury site, and improved the microenvironment. Therefore, this prevascularization system may provide a better therapeutic option for SCI.