Department of Urology, Shanghai Children's Hospital, Shanghai Jiao Tong University, Shanghai 200062, China.
Department of Urology, Shanghai Jiao Tong University Affiliated Sixth People's Hospital, Shanghai 200233, China.
Theranostics. 2020 Aug 20;10(23):10378-10393. doi: 10.7150/thno.47006. eCollection 2020.
Construction of functional vascularized three-dimensional tissues has been a longstanding objective in the field of tissue engineering. The efficacy of using a tissue expander capsule as an induced vascular bed to prefabricate functional vascularized smooth muscle tissue flaps for bladder reconstruction in a rabbit model was tested. Skin tissue expanders were inserted into the groin to induce vascularized capsule pouch formation. Smooth muscle cells and endothelial progenitor cells were harvested and cocultured to form pre-vascularized smooth muscle cell sheet. Then repeated transplantation of triple-layer cell sheet grafts onto the vascularized capsular tissue was performed at 2-day intervals to prefabricate functional vascularized smooth muscle tissue flaps. Bladder muscular wall defects were created and repaired by six-layer cell sheet graft (sheet only), capsule flap (capsule only) and vascularized capsule prelaminated with smooth muscle cell sheet (sheet plus capsule). The animals were followed for 3 months after implantation and their bladders were explanted serially. Bladder capacity and compliance were maintained in sheet plus capsule group throughout the 3 months. Tissue bath stimulation demonstrated that contractile responses to carbachol and KCl among the three groups revealed a significant difference ( 0.05). Histologically, inflammation was evident in the capsule only group at 1 month and fibrosis was observed in sheet only group at 3 months. The vessel density in capsule only and sheet plus capsule group were significantly higher than in the sheet only group at each time point ( 0.05). Comparison of the smooth muscle content among the three groups revealed a significant difference ( 0.05). These results proved that the capsule may serve as an induced vascular bed for vascularized smooth muscle tissue flap prefabrication. The prefabricated functional vascularized smooth muscle tissue flap has the potential for reliable bladder reconstruction and may create new opportunities for vascularization in 3-D tissue engineering.
构建具有功能的血管化三维组织一直是组织工程领域的一个长期目标。本研究旨在测试使用组织扩张器胶囊作为诱导性血管床预制功能性血管化平滑肌组织皮瓣用于兔模型膀胱重建的效果。将皮肤组织扩张器插入腹股沟以诱导血管化胶囊袋形成。收获平滑肌细胞和内皮祖细胞并共培养以形成预血管化平滑肌细胞片。然后每隔 2 天重复将三层细胞片移植物移植到血管化胶囊组织上，以预制功能性血管化平滑肌组织皮瓣。通过六层细胞片移植物（仅片）、胶囊皮瓣（仅胶囊）和预先用平滑肌细胞片预层压的血管化胶囊（片加胶囊）修复膀胱肌壁缺损。植入后动物随访 3 个月，并连续取出膀胱。在整个 3 个月中，片加胶囊组的膀胱容量和顺应性得以维持。组织浴刺激显示，三组的收缩反应对卡巴胆碱和 KCl 存在显著差异（ 0.05）。组织学上，仅胶囊组在 1 个月时可见炎症，仅片组在 3 个月时可见纤维化。仅胶囊组和片加胶囊组的血管密度在每个时间点均显著高于仅片组（ 0.05）。三组之间的平滑肌含量比较存在显著差异（ 0.05）。这些结果证明胶囊可作为血管化平滑肌组织皮瓣预制的诱导性血管床。预制的功能性血管化平滑肌组织皮瓣具有可靠的膀胱重建潜力，并可能为 3D 组织工程中的血管化创造新的机会。
