基于自体血管床培育带蒂膀胱组织瓣的研究

The reconstruction of tissue and organ by tissue engineering is one of the potential treatments for the tissue defect and organ failure. The current main problem that tissue engineering is facing is how to build the blood supply timely after the in vitro engineered tissue is implanted into the body to avoid shrinkage or failed tissue formation. Our previous studies showed that implanting tissue expander subcutaneously followed by expanding could induce the formation of peri-implant capsule which is rich in vascular plexus. And if the expander is set beside the larger blood vessels or their branches, this vascular plexus would connect with them, meaning that the larger blood vessels can serve as the axial vessel for the capsule. Based on the above, we plan to implant a tissue expander subcutaneously beside inferior epigastric vessels on the lower abdominal part of a New Zealand white rabbit to develop a peri-implant capsule as a vascular bed for the tissue formation. The cell sheets composed of SMCs, EPCs and their ECM harvested from temperature-responsive culture surfaces would be transplanted onto the inner surface of the capsule. With the formation of bladder smooth muscle, its vascularization by the capsule proceeds continuously as well, as a result, a vascularized engineered tissue will be generated. After that, with the inferior epigastric vessels as the vascular pedicle, this island capsule tissue flap containing the newly-formed bladder smooth muscle will be raised and transplanted onto bladder wall with a muscular layer defect on supratrigonal area. By investigating the histological features and bladder functions after this process, we will find out the possibility of the tissue expander capsule to work as vascular bed to construct vascularized engineered-tissue with its own axial vessels.

组织工程组织和器官重建是临床治疗组织缺损和脏器功能衰竭的潜在途径之一，但目前面临的主要问题是在体外构建的组织植入体内后不能及时获得血供，故而萎缩、无法成形。在前期研究发现皮肤扩张器植入皮下后，其表面可形成富含血管、并与较大血管分支连接的包膜的基础上，申请者拟在新西兰大白兔下腹部皮下毗邻膀胱的腹壁下动静脉旁埋置皮肤扩张器形成包膜，将温敏培养系统中收获的膀胱平滑肌细胞和内片祖细胞混合复层细胞片置于该包膜形成的血管床上，在体培育具有血管网络的膀胱平滑肌组织瓣；再以腹壁下动静脉为血管蒂将构建的该组织瓣岛状转移至膀胱壁肌层缺损处，根据膀胱修复后的组织学特征和功能情况来探讨扩张器包膜作为组织培养用血管床构建具有血管网络、含轴心血管的组织的可行性，以解决组织工程血管系统构建的难题。

血管系统的构建是组织工程组织发展及应用的关键：没有足够血供，将无法形成真正的功能化组织。本研究在新西兰大白兔腹股沟区皮下靠近旋髂浅动静脉旁埋置皮肤扩张器形成包膜，将通过普通培养皿共培养收获的膀胱平滑肌细胞和内片祖细胞复合细胞片移植于该包膜血管床上，在体培育具有血管网络的膀胱平滑肌组织瓣；再以旋髂浅动静脉为血管蒂将构建的该组织瓣岛状转移至膀胱壁肌层缺损处，观察组织瓣存活情况。首先将皮肤扩张器埋置于旋髂浅动静脉旁并间歇性注水扩张完毕后1周，可得到血管密度最为丰富的轴型包膜血管床，且包膜血供来源于轴心血管。包膜血管床与传统皮下组织相比，更有利于细胞片移植物的孵育和血管化，而且可以在此平台构建带蒂的平滑肌组织瓣。同时，我们对传统温敏培养法进行改良，将膀胱平滑肌细胞和内片祖细胞按6：1比例在普通培养皿中共培养5天时间，即可收获完整的、可分泌血管生成因子的预血管化细胞片，其相比于单纯平滑肌细胞片更有利于工程平滑肌组织的构建。最后，将共培养细胞片多次移植于包膜血管床并孵育，然后带蒂移植至膀胱壁浆肌层缺损区，岛状组织瓣能够成活。综合上述结果，本研究为解决组织工程组织植入受区后缺乏血供的难题提供了新的思路和方法。本项目资助发表SCI论文4篇，核心期刊论文3篇。培养研究生4名，其中博士研究生3名，硕士研究生1名。项目预算经费73万元，支出57.71万元，各项支出基本与预算相符。剩余经费15.29万元，剩余经费计划用于本项目研究的后续支出。