Development of a VEGF-activated scaffold with enhanced angiogenic and neurogenic properties for chronic wound healing applications - Data

Abstract: Chronic wounds remain in a state of disrupted healing, manifest by impeded neurite outgrowth from injured nerves and poor development of new blood vessels by angiogenesis. Current therapeutic approaches primarily focus on the restoration of vascularization and overlook the need of nerve regeneration for complete healing. Vascular endothelial growth factor (VEGF) is a critical growth factor supporting angiogenesis in wound healing, promoting vascularization and has also demonstrated neuro-protective capabilities in both central, and peripheral nervous system. While the delivery of pro-regenerative recombinant growth factors has shown promise, gene delivery offers greater stability, reduced off-target side effects, diminished cytotoxicity, and lower production costs. In this context, the overarching goal of this study was to develop a VEGF-activated scaffold with the potential to provide a multifaceted response that enhances both angiogenesis and nerve repair in wound healing through the localized delivery of plasmid encoding VEGF (pVEGF) encapsulated within the GET peptide system. Initially, delivery of pVEGF/GET nanoparticles to dermal fibroblasts led to higher VEGF protein expression without a compromise in cell viability. Transfection of dermal fibroblasts and endothelial cells on a gene-activated collagen-GAG scaffold resulted in enhanced VEGF expression, improved endothelial cell migration and organization into vascular-like structures. Finally, the VEGF-activated scaffolds consistently displayed enhanced neurogenic ability through improved neurite outgrowth from neural cells in in vitro and ex vivo models. Taken together, the VEGF-activated scaffold demonstrates multifaceted outcomes through the induction of pro-angiogenic and neurogenic responses from dermal, vascular and neural cells, illustrating the potential of this platform for the healing of chronic wounds.

摘要：慢性伤口始终处于愈合中断的状态，其特征为受损神经的神经突生长受阻，且血管生成过程中新血管发育不良。当前的治疗策略主要聚焦于血管化的恢复，却忽略了实现完全愈合所需的神经再生需求。血管内皮生长因子（Vascular Endothelial Growth Factor, VEGF）是伤口愈合过程中支持血管生成、促进血管化的关键生长因子，同时在中枢及外周神经系统中均展现出神经保护功能。尽管促再生重组生长因子的递送已展现出应用前景，但基因递送具有更高的稳定性、更低的脱靶副作用、更弱的细胞毒性以及更低的生产成本。在此背景下，本研究的总体目标是开发一种VEGF激活支架，该支架可通过封装于GET肽系统中的编码VEGF的质粒（pVEGF）的局部递送，实现多维度应答，从而在伤口愈合过程中同时增强血管生成与神经修复。初始实验中，将pVEGF/GET纳米颗粒递送至皮肤成纤维细胞后，可在不影响细胞活力的前提下，提升VEGF蛋白的表达水平。在基因激活型胶原-糖胺聚糖支架上对皮肤成纤维细胞与内皮细胞进行转染，可提升VEGF表达水平，改善内皮细胞的迁移能力，并促进其组装为血管样结构。最后，在体外与离体模型中，VEGF激活支架可通过促进神经细胞的神经突生长，持续展现出增强的神经生成能力。综上，VEGF激活支架可通过诱导皮肤细胞、血管细胞与神经细胞产生促血管生成及神经生成应答，实现多维度的治疗效果，证明了该平台在慢性伤口愈合中的应用潜力。