A nanofiber-hydrogel composite plug for perianal fistula repair

摘要 肛周瘘(PAF)发生在30-40%的克罗恩病患者中，他们的并发症导致 生活质量严重受损。目前的治疗方法在不到50%的病例中有效。整体而言 本研究的目的是开发一种生物刺激纳米纤维-水凝胶复合材料(NHC)塞子，以 促进组织愈合，并在临床相关动物模型上测试其修复PAF的效果。以前的工作 为这项研究奠定了基础。具体地说，我们已经建立了新型啮齿动物 和猪的PAF模型，忠实地概括了PAF患者的生物学特性。与此同时，我们已经开发出 聚己内酯(PCL)第一代可注射生物降解纳米纤维-水凝胶复合材料 纳米纤维共价连接到透明质酸(HA)水凝胶上；并证明了其输送脂肪的能力 干细胞(ADSCs)和修复PAF，通过调节炎症反应，允许宿主细胞渗透，以及 促进血管生成和进行性重塑。在这些初步结果的基础上，我们计划 第二代NHC插头具有增强的机械强度和完整性，作为现成设备和 优化其生物刺激活性，以诱导对瘘管愈合更有利的细胞反应。我们 假设这种具有结构、机械和生物功能优化特征的NHC插头将 有效促进血管生成和软组织修复；作为ADSCs和ADSC的载体- 衍生的外切体进一步改善了PAF的组织愈合。要检验这一假设并证明其 翻译潜力，我们将追求三个具体目标(1)开发一种基于胶原纳米纤维的NHC插头 最佳的机械性能和多孔结构，便于植入以支持肛周瘘愈合， (2)利用大鼠模型评价单独或与ADSCs联合应用对PAF愈合的影响 ADSC来源的外切体，并通过评估细胞渗透来阐明促进再生的机制。 血管生成、细胞外基质沉积和组织重建，以及(3)利用猪模型 通过将优化的NHC插头与ADSC衍生产品相结合，展示组织重塑中的协同效应 外显体。这项研究将提供一种可翻译的现成的仿生NHC微孔塞子用于交付 ADSC来源的外体能够促进软组织重塑和愈合以修复PAF。

SUMMARY Perianal fistulas (PAF) occur in 30-40% of Crohn’s disease patients and their complications lead to a significant impairment in quality of life. Current treatments are effective in less than 50% of cases. The overall objective of this proposed study is to develop a biostimulatory nanofiber-hydrogel composite (NHC) plug to promote tissue healing and to test its efficacy to repair PAF in clinically relevant animal models. Previous work from the Mao and Selaru labs laid the foundation for this study. Specifically, we have established novel rodent and swine models of PAF that faithfully recapitulate the biology of PAF in patients. In parallel, we have developed a first-generation injectable biodegradable nanofiber-hydrogel composite (NHC) from poly(e-caprolactone) (PCL) nanofibers covalently bonded to hyaluronic acid (HA) hydrogel; and demonstrated its ability to deliver adipose stem cells (ADSCs) and repair PAF by conditioning inflammatory responses, permitting host cell infiltration, and facilitating angiogenesis and progressive remodeling. Building on these preliminary results, we plan to engineer a second generation NHC plug with enhanced mechanical strength and integrity as an off-the-shelf device and optimize its biostimulatory activities to induce more favorable cellular responses governing fistula healing. We hypothesize that this NHC plug with structurally, mechanically, and biofunctionally optimized features will effectively promote angiogenesis and soft tissue restoration; and serve as a carrier for ADSCs and ADSC- derived exosomes to further improve the PAF tissue healing. To test this hypothesis and demonstrate its translational potential, we will pursue three specific aims (1) develop a collagen nanofiber-based NHC plug with optimal mechanical properties and porous structure for ease of implantation to support perianal fistula healing, (2) utilize a rat model to evaluate the efficacy for PAF healing when used alone or in conjunction with ADSCs or ADSC-derived exosomes, and elucidate the pro-regenerative mechanism by assessing cell infiltration, angiogenesis, extracellular matrix deposition, and tissue remodeling, and (3) utilize a swine model to demonstrate the synergistic effect in tissue remodeling by combining the optimized NHC plug with ADSC-derived exosomes. This study will deliver a translatable off-the-shelf biomimetic NHC microporous plugs for the delivery of ADSC-derived exosomes capable of promoting soft tissue remodeling and healing for PAF repair.