异种移植微囊化新生猪胰岛细胞受体感染PERV潜在风险分析

Potential risk of porcine endogenous retrovirus cross-species transmission in neonatal pig islets under xenotransplanted condition

目的:研究新生猪胰岛细胞(neonatal pig islets,NPIs)经微囊化后异种移植到狗体内,受体感染猪内源性逆转录病毒(porcine endogenous retrovirus,PERV)的风险。方法:将10只狗随机分成实验组和对照组,分别移植微囊化猪胰岛细胞和未被微囊化猪胰岛细胞。应用放射免疫的方法检测狗体内血清特异性猪C-肽以判断胰岛移植物活性;采用免疫组织化学技术检测28d后肝移植部位是否有微囊化猪胰岛细胞;PCR和RT-PCR技术分别检测不同时间点狗外周血中PERV及猪mt DNA。结果:移植微囊化猪胰岛细胞2周后,给受体注射葡萄糖,15～30min狗的外周血中猪C-肽表达明显升高,而对照组检测不到猪C-肽;免疫组化结果表明,狗肝脏移植部位周围可检测到少量微囊化猪胰岛细胞,肝组织无明显异常;PCR和RT-PCR结果表明,移植微囊化猪胰岛细胞在不同时间点狗外周血内均未检测到猪mt DNA及PERV表达,而对照组于移植后4d内检测到猪mt DNA及PERV呈微弱表达,10d后均未见表达。结论:微囊化猪胰岛细胞能够在受体肝脏内存活并发挥作用,受体内不存在PERV的感染,提示海藻酸钠微囊可以有效地防止猪mt DNA及PERV的穿越,可能在异种移植中具有较好的应用前景。

Objective To evaluate the potential risk of porcine endogenous retrovirus （PERV） cross-species transmission xenotransplanted with microencapsulated neonatal pig islets （NPIs）. Methods Ten dogs were randomly divided into an experiment group and a control group. The experiment group was transplanted with microencapsulated NPIs, and the control group was trans- planted with non-microencapsulated NPIs. Glucose tolerance test （GTY） was performed to evaluate the function of microencapsulated NPIs after the transplantation;immunity hisochemistry was used to detect the microencapsulated NPIs in the liver of dogs which had been transplanted after 28 days; PCR and RT-PCR were performed to detect PERV and pig mitochondrial （mt） DNA in the blood samples obtained from recipients at various time points after the transplantation. Results The level of serum special porcine C peptide increased significantly after the injection of glucose for 15 - 30 min in dogs which were transplanted with the micro-encapsulated NPIs over 2 weeks, while special porcine C peptide could not be detected in the control group. Immunity hisochemistry showed that a few microencapsulated NPIs were still alive in the liver of the dog, and the liver was not damaged. PCR and RT-PCR showed that pig mt DNA and PERV could not be detected in the experiment group I - 28 days after the transplantation, while very weak expression of that in the control could be detected in the first 4 days and disappeared 10 days after the transplantation. Conclusion Microencapsulated NPIs can survive and have biological function in dogs. There is no evidence of PERV replication, suggesting that the xenotransplantion with microencapsulated NPIs can prevent PERV effectively, and may have great value.