弱亲水性PLA/gelatin纳米纤维管复合种子细胞构建血管化组织工程尿道的实验研究

Long urethral tissue defect repair and functional reconstruction are one of the problems in urological treatment. Although a variety of tissue engineered autologous urethral mucosa have been developed in the animal and clinical studies of urethra reconstruction, there is a shortcoming of slow vascularization process in the internal of theses scaffolds, which limits the transformation of the technology into clinical applications. Applicants' previous studies have shown that weakly hydrophilic scaffolds colud enhance neovascularization, but the mechanism is unknown. Recent pre-experiments have found that weak hydrophilic polylactic acid-gelatin (PLA/gelatin) nanofiber scaffolds can carry sufficient autologous epithelial and smooth muscle cells to rapidly achieve scaffold internal vascularization in vivo. It is suggested that weak hydrophilicity is a key factor for rapid vascularization after tissue engineered scaffold implantation in vivo. Further in vitro biological experiments showed that the weakly hydrophilic PLA/gelatin scaffold can timely recruit macrophages to induce high expression of pro-angiogenic factors in their scaffolds. This project is to explore the mechanism and process of vascularization of the tissue-engineered PLA/gelatin urethra in vivo, and preliminarily elucidated the biological mechanism of its vascularization process in the urethral mucosal reconstruction. To solve the problem of “insufficient vascularization” in the internal of long urethral scaffold in urethral tissue engineering research, a new idea and a new method are provided.

幼儿长段尿道组织缺损修复及功能重建是泌尿外科治疗病例中的难题之一。虽然现行已开发的多种组织工程人造尿道黏膜在尿道重建的动物和临床研究中均取得了一定的成功，但仍存在支架内部血管化进程慢的缺点，限制了该项技术向临床应用的转化。申请人以往研究表明：弱亲水性的支架具有增强的血管化功能，但机制不明。近期预实验发现：弱亲水性聚乳酸-明胶（PLA/gelatin）纳米纤维支架可携带充足的自体上皮和平滑肌细胞在体内快速实现支架内部血管化，提示弱亲水性是组织工程支架植入体内后快速血管化的关键因素。进一步生物学实验结果显示弱亲水的PLA/gelatin支架可适时募集巨噬细胞而引发促血管生成因子在其支架内部高表达。本项目拟探讨该组织工程尿道在体内血管化的机理及过程；并初步阐明其血管化进程在尿道管腔黏膜重建中的生物学机制，为解决尿道组织工程研究中长段尿道支架内部的“血管化不足”难题而提供一种新思路和新方法。

各种原因所引起的婴幼儿长段尿道组织缺损修复和功能重建是泌尿外科治疗病例中的难题之一。虽然现行已开发的多种组织工程尿道支架移植物在尿道重建的动物乃至临床研究中均取得了一定的成功，但这些支架在移植到尿道伤口部位后的血管化进程比较慢，在一些长尿道缺损病例中经常失败，限制了该项技术向临床应用的转化。申请人团队前期研究中发现：支架弱亲水可以影响免疫细胞的招募和随后的免疫反应，但机制未明。基于前期预实验结果，我们较系统研究了本项目开发的弱亲水性聚乳酸（PLA）-明胶（gelatin）（PLA/gelatin）复合多层管状纳米纤维支架如何操纵创伤性尿道伤口中的免疫微环境，以促进组织再生。提出“支架的弱亲水通过调节细胞外微环境促进血管化组织再生”的科学假设。明确了支架弱亲水性在创伤部位与其宿主巨噬细胞互作是调节再生的重要介质，探讨了支架先天免疫细胞互作在尿道再生中的作用，确定了支架巨噬细胞相互作用在推动创伤性尿道损伤的修复中至关重要。本项目的研究结果包含5篇SCI论著（IF>10的一篇，10>IF>6的四篇），一项国内发明专利（已授权）。