根据一份新的报告，干细胞疗法可能是治疗血友病A的新疗法的关键。血友病是一种遗传病，其患者的血液不能正常凝结。Yupo Ma及其同事培育了一种改造的干细胞，它可以让血友病小鼠产生血友病A患者缺失的蛋白质，这可以让这些小鼠在受伤后停止出血。此前用基因疗法治疗血友病的尝试因为各种原因而失败了，包括被免疫系统排斥。

这组科学家使用了能制造第八因子蛋白质的小鼠纤维原细胞，然后把这些改造后的细胞注射进了血友病小鼠的肝脏。在注射的7天后，接受治疗的小鼠产生了当它们的尾巴被切掉时足以制止出血的第八因子，而未经治疗的小鼠在几小时之后就死亡了。接受治疗的小鼠产生的第八因子只有健康小鼠的大约16%，然而，这种治疗看上去足够防止大量出血，并可以逆转血友病A的主要症状。这组作者提出，这种类型的干细胞疗法还可能被证明对于治疗其他遗传病有用。

推荐原始出处：

PNAS January 12, 2009, doi: 10.1073/pnas.0812090106

Phenotypic correction of murine hemophilia A using an iPS cell-based therapy

Dan Xua, Zaida Alipioa, Louis M. Finka, Dorothy M. Adcockb, Jianchang Yanga, David C. Warda,1 and Yupo Maa,1

aDivision of Laboratory Medicine, Nevada Cancer Institute, Las Vegas, NV 89135; and
bEsoterix Coagulation, Englewood, CO 80112

Abstract

Hemophilia A is caused by mutations within the Factor VIII (FVIII) gene that lead to depleted protein production and inefficient blood clotting. Several attempts at gene therapy have failed for various reasons—including immune rejection. The recent generation of induced pluripotent stem (iPS) cells from somatic cells by the ectopic expression of 3 transcription factors, Oct4, Sox2, and Klf4, provides a means of circumventing the immune rejection barrier. To date, iPS cells appear to be indistinguishable from ES cells and thus provide tremendous therapeutic potential. Here we prepared murine iPS cells from tail-tip fibroblasts and differentiated them to both endothelial cells and endothelial progenitor cells by using the embryoid body differentiation method. These iPS cells express major ES cell markers such as Oct4, Nanog, SSEA-1, alkaline phosphatase, and SALL4. Endothelial/endothelial progenitor cells derived from iPS cells expressed cell-specific markers such as CD31, CD34, and Flk1 and secreted FVIII protein. These iPS-derived cells were injected directly into the liver of irradiated hemophilia A mice. At various times after transplantation (7–90 days) hemophilia A mice and their control mice counterparts were challenged by a tail-clip bleeding assay. Nontransplanted hemophilia A mice died within a few hours, whereas transplanted mice survived for more than 3 months. Plasma FVIII levels increased in transplanted hemophilia A mice during this period to 8% to 12% of wild type and corrected the hemophilia A phenotype. Our studies provide additional evidence that iPS cell therapy may be able to treat human monogenetic disorders in the future.