Miranda S R, Erlich S, Friedrich V L, Gatt S, Schuchman E H
Department of Human Genetics, Mount Sinai School of Medicine, New York, NY 10029, USA.
Gene Ther. 2000 Oct;7(20):1768-76. doi: 10.1038/sj.gt.3301300.
Types A and B Niemann-Pick disease (NPD) result from the deficient activity of acid sphingomyelinase (ASM). Currently, no treatment is available for either form of NPD. Using the ASM knockout (ASMKO) mouse model, we evaluated the effects of ex vivo hematopoietic stem cell gene therapy on the NPD phenotype. Thirty-two newborn ASMKO mice were preconditioned with low dose radiation (200 cGy) and transplanted with ASMKO bone marrow cells which had been transduced with an ecotropic retroviral vector encoding human ASM. Engraftment of donor-derived cells ranged from 15 to 60% based on Y-chromosome in situ hybridization analysis of peripheral white blood cells, and was achieved in 92% of the transplanted animals. High levels of ASM activity (up to five-fold above normal) were found in the engrafted animals for up to 10 months after transplantation, and their life-span was extended from a mean of 5 to 9 months by the gene therapy procedure. Biochemical and histological analysis of tissues obtained 4-5 months after transplantation indicated that the ASM activities were increased and the sphingomyelin storage was significantly reduced in the spleens, livers and lungs of the treated mice, major sites of pathology in type B NPD. The presence of Purkinje cell neurons was also markedly increased in the treatment group as compared with non-treated animals at 5 months after transplantation, and a reduction of storage in spinal cord neurons was observed. However, all of the transplanted mice eventually developed ataxia and died earlier than normal mice. Overall, these results indicated that hematopoietic stem cell gene therapy should be effective for the treatment of non-neurological type B NPD, but improved techniques for targeting the transplanted cells and/or expressed enzyme to specific sites of pathology in the central nervous system must be developed in order to achieve effective treatment for type A NPD.
A型和B型尼曼-匹克病（NPD）是由酸性鞘磷脂酶（ASM）活性不足引起的。目前，这两种形式的NPD均无可用的治疗方法。我们使用ASM基因敲除（ASMKO）小鼠模型，评估了体外造血干细胞基因治疗对NPD表型的影响。32只新生ASMKO小鼠接受低剂量辐射（200 cGy）预处理，然后移植用编码人ASM的嗜亲性逆转录病毒载体转导的ASMKO骨髓细胞。根据外周血白细胞的Y染色体原位杂交分析，供体来源细胞的植入率为15%至60%，92%的移植动物实现了植入。移植后长达10个月的时间里，在植入的动物中发现了高水平的ASM活性（比正常水平高五倍），并且通过基因治疗程序，它们的寿命从平均5个月延长到了9个月。移植后4至5个月获得的组织的生化和组织学分析表明，治疗小鼠的脾脏、肝脏和肺（B型NPD的主要病理部位）中的ASM活性增加，鞘磷脂蓄积显著减少。与未治疗的动物相比，移植后5个月时治疗组中浦肯野细胞神经元的数量也明显增加，并且观察到脊髓神经元中的蓄积减少。然而，所有移植小鼠最终都出现共济失调，并且比正常小鼠更早死亡。总体而言，这些结果表明造血干细胞基因治疗对于治疗非神经型B型NPD应该是有效的，但是必须开发改进的技术，以便将移植细胞和/或表达的酶靶向中枢神经系统中的特定病理部位，从而实现对A型NPD的有效治疗。
