组织工程预血管化处理对胰岛移植的影响

Effects of pre-vascularization of tissue-engineered constructs on the survival of transplanted pancreatic islets

背景:临床门静脉系统胰岛移植后局部缺氧导致大量胰岛细胞凋亡,影响移植效果。目的:分析组织工程方法预先在局部形成微血管网络化对移植胰岛存活的影响以及异种胰岛移植的可行性。方法:将5 mm长圆柱形中空硅胶管置入糖尿病小鼠腹股沟区,中央包绕腹壁血管,注入MatrigelTM细胞培养基。分别于预血管化处理0,14以及28 d在硅胶管小室中移植同基因300个胰岛当量(IEQ)小鼠胰岛细胞,观察血糖恢复至正常时间。另在28 d于硅胶管小室内分别移植100 IEQ、200 IEQ以及300 IEQ小鼠胰岛细胞,检测血糖变化。最后将1 000 IEQ人胰岛细胞分别移植到已血管化的硅胶管小室或小鼠肾脏包膜下,并用抗CD45RB或/和抗CD40L(MR-1)抗体治疗,比较人胰岛细胞在两者中的生存情况。结果与结论:(1)硅胶管小室在构建28 d后可建立丰富的微血管网。(2)糖尿病小鼠血糖恢复至正常水平所需的时间与预血管化处理时间以及植入的胰岛数量均呈负相关。(3)移植至硅胶管小室的人胰岛细胞经抗CD45RB抗体治疗后无一例长期存活,加用MR-1抗体后7只中有1只长期存活,与肾包膜下移植组(n=8,平均生存时间>71 d)比较生存时间差异无显著性意义(P>0.05)。在胰岛移植之前通过组织工程方法预血管化处理可显著延长移植物的存活时间。将异种胰岛移植在血管化的硅胶管小室内或为以后的临床应用提供有意义的探索。

BACKGROUND：Pancreatic islet transplantation via portal vein system leads to the apoptsis of a number of islet cells due to local hypoxia,thereby affecting transplant outcomes.OBJECTIVE：To explore the effect of pre-micrvascularization network of tissue-engineered constructs on the survival of transplanted islets and the feasibility of xenogenic islet transplantation.METHODS：A 5-mm-long cylindrical silicone tube filled with Matrigel TM matrix surrounding the superficial epigastric vessel was placed in the groin of diabetic mice.After the syngeneic islets with 300 islet equivalents（IEQ） were transplanted into the silicone chamber on days 0,14 and 28 post-chamber implantation,respectively,the recovery time of blood glucose was observed.The islets with the quantity of 100 IEQ,200 IEQ and 300 IEQ,respectively,were transplanted on day 28 post-implantation and then the blood glucose level was determined.Moreover,the survival of human pancreatic islets with 1 000 IEQ transplanted into the pre-vascularizated chamber or under the renal capsule of diabetic mice,followed by the treatment of anti-CD45 RB and/or anti-CD40L（MR-1） was analyzed.RESULTS AND CONCLUSION：An abundant micro-vascularized network was established in the silicone chamber on day 28 post-implantation.The time of the blood glucose returning to normal level in diabetic mice was negatively correlated with the time required for pre-vascularization and the number of implanted islets.No islet grafts implanted in the silicone chamber and treated by anti-CD45 RB survived for long term.However,one of seven（14.3%） grafts survived for long term,which was not significantly different from the transplantation under the renal capsule group（n=8,MST 71 days,P 0.05）.The tissue-engineered pre-vascularization network markedly extends the survival time of the islet grafts before transplantation.The transplantation of the xenogenic pancreatic islets into the vascularized silicone chamber might be a promising method in the future clinical application.