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Traumatic brain injury (TBI), especially moderate or severe TBI, is one of the most devastating injuries to the nervous system, as the existing therapies for neurological defect repair have difficulty achieving satisfactory results. Neural stem cells (NSCs) therapy is a potentially effective treatment option, especially after specific genetic modifications and when used in combination with biomimetic biological scaffolds. In this study, tussah silk fibroin (TSF) scaffolds with interconnected nanofibrous structures were fabricated using a top-down method. We constructed the apelin-overexpressing NSCs that were cocultured with a TSF nanofiber scaffold (TSFNS) that simulated the extracellular matrix in vitro. To verify the therapeutic efficacy of engineered NSCs in vivo, we constructed TBI models and randomized the C57BL/6 mice into three groups: a control group, an NSC-ctrl group (transplantation of NSCs integrated on TSFNS), and an NSC-apelin group (transplantation of apelin-overexpressing NSCs integrated on TSFNS). The neurological functions of the model mice were evaluated in stages. Specimens were obtained 24 days after transplantation for immunohistochemistry, immunofluorescence, and western blot experiments, and statistical analysis was performed. The results showed that the combination of the TSFNS and apelin overexpression guided extension and elevated the proliferation and differentiation of NSCs both in vivo and in vitro. Moreover, the transplantation of TSFNS-NSCs-Apelin reduced lesion volume, enhanced angiogenesis, inhibited neuronal apoptosis, reduced blood-brain barrier damage, and mitigated neuroinflammation. In summary, TSFNS-NSC-Apelin therapy could build a microenvironment that is more conducive to neural repair to promote the recovery of injured neurological function. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]