Xian Bikun, Huang Bing
State Key Laboratory of Ophthalmology, Zhongshan Ophthalmic Center, Sun Yat-sen University, Guangzhou, 510060, Guangdong Province, China.
Stem Cell Res Ther. 2015 Sep 14;6:161. doi: 10.1186/s13287-015-0167-1.
Stem cell transplantation is a potential curative treatment for degenerative diseases of the retina. Among cell injection sites, the subretinal space (SRS) is particularly advantageous as it is maintained as an immune privileged site by the retinal pigment epithelium (RPE) layer. Thus, the success of subretinal transplantation depends on maintenance of RPE integrity. Moreover, both embryonic stem cells (ESCs) and mesenchymal stem cells (MSCs) have negligible immunogenicity and in fact are immunosuppressive. Indeed, many studies have demonstrated that immunosuppressive drugs are not necessary for subretinal transplantation of stem cells if the blood-retinal barrier is not breached during surgery. The immunogenicity of induced pluripotent stem cells (iPSCs) appears more complex, and requires careful study before clinical application. Despite low rates of graft rejection in animal models, survival rates for ESCs, MSCs, and iPSCs in retina are generally poor, possibly due to resident microglia activated by cell transplantation. To improve graft survival in SRS transplantation, damage to the blood-retinal barrier must be minimized using appropriate surgical techniques. In addition, agents that inhibit microglial activation may be required. Finally, immunosuppressants may be required, at least temporarily, until the blood-retinal barrier heals. We review surgical methods and drug regimens to enhance the likelihood of graft survival after SRS transplantation.
干细胞移植是视网膜退行性疾病的一种潜在治愈性治疗方法。在细胞注射部位中,视网膜下间隙(SRS)具有特别的优势,因为视网膜色素上皮(RPE)层将其维持为一个免疫豁免部位。因此,视网膜下移植的成功取决于RPE完整性的维持。此外,胚胎干细胞(ESC)和间充质干细胞(MSC)的免疫原性都可忽略不计,实际上还具有免疫抑制作用。确实,许多研究表明,如果手术过程中血视网膜屏障未被破坏,干细胞视网膜下移植无需使用免疫抑制药物。诱导多能干细胞(iPSC)的免疫原性似乎更为复杂,在临床应用前需要仔细研究。尽管在动物模型中移植物排斥率较低,但ESC、MSC和iPSC在视网膜中的存活率通常较差,这可能是由于细胞移植激活了视网膜中的常驻小胶质细胞。为提高SRS移植中的移植物存活率,必须使用适当的手术技术将血视网膜屏障的损伤降至最低。此外,可能需要抑制小胶质细胞激活的药物。最后,可能至少在血视网膜屏障愈合之前需要暂时使用免疫抑制剂。我们综述了提高SRS移植后移植物存活可能性的手术方法和药物方案。