iPSCs来源的血细胞在血液系统疾病中的应用与发展

骨髓（BM）移植已在许多血液病中成功应用多年,主要依赖于成人BM和外周血（PB）中的造血干细胞（HSCs）。然而,合适配型HSCs的稀缺限制了其临床应用,难以满足更多有需要的患者。诱导多能干细胞（iPSCs）的出现,有望解决这一难题。iPSCs具有分化成所有血细胞的潜能,使得HSCs和其他血细胞在血液病中的广泛应用成为可能。然而,临床应用iPSCs治疗血液病仍障碍重重。本文主要回顾了iPSCs在血液病中的应用和发展以及面临的问题和挑战。     

Embryoid body formation from embryonic and induced pluripotent stem cells: Benefits of bioreactors

Embryonic stem (ES) cells have the ability to differentiate into all germ layers, holding great promise not only for a model of early embryonic development but also for a robust cell source for cell-replacement therapies and for drug screening. Embryoid body (EB) formation from ES cells is a common method for producing different cell lineages for further applications. However, conventional techniques such as hanging drop or static suspension culture are either inherently incapable of large scale production or exhibit limited control over cell aggregation during EB formation and subsequent EB aggregation. For standardized mass EB production, a well defined scale-up platform is necessary. Recently, novel scenario methods of EB formation in hydrodynamic conditions created by bioreactor culture systems using stirred suspension systems (spinner flasks), rotating cell culture system and rotary orbital culture have allowed large-scale EB formation. Their use allows for continuous monitoring and control of the physical and chemical environment which is difficult to achieve by traditional methods. This review summarizes the current state of production of EBs derived from pluripotent cells in various culture systems. Furthermore, an overview of high quality EB formation strategies coupled with systems for in vitro differentiation into various cell types to be applied in cell replacement therapy is provided in this review. Recently, new insights in induced pluripotent stem (iPS) cell technology showed that differentiation and lineage commitment are not irreversible processes and this has opened new avenues in stem cell research. These cells are equivalent to ES cells in terms of both self-renewal and differentiation capacity. Hence, culture systems for expansion and differentiation of iPS cells can also apply methodologies developed with ES cells, although direct evidence of their use for iPS cells is still limited.     

人诱导多能干细胞与人胚胎干细胞分化过程中Oct4/Nanog基因表达的比较

目的：比较通过慢病毒方法获得的人诱导多能性干细胞（iPSCs）与人胚胎干细胞（hESCs）分化过程中全能性基因Oct4、Nanog的表达变化。方法：收集分化不同时间点的拟胚体（EBs）,检测三胚层分化基因以及全能性基因Oct4/Nanog的表达,并通过畸胎瘤组织切片的荧光染色分析Oct4的表达。结果：iPSCs获得的EB中内外三胚层分化基因表达的出现明显晚于hESCs来源的EB。不同于hESCs,iPSCs悬浮培养获得的EBs在体外培养18天未见内源性Oct4、Nanog基因表达的下调。未分化的iPSCs注射严重联合免疫缺陷（SCID）小鼠培养10周后获得的畸胎瘤中仍存在Oct4阳性的细胞,但iPS-#2中明显少于iPS-#5。结论：通过慢病毒方法获得的iPSCs虽然具有向三胚层分化的能力,但在分化过程中仍维持较高水平的全能性基因Oct4、Nanog的表达。     

人诱导多能干细胞与人胚胎干细胞分化过程中Oct4/Nanog 基因表达的比较

目的:比较通过慢病毒方法获得的人诱导多能性干细胞(iPSCs)与人胚胎干细胞(hESCs)分化过程中全能性基因Oct4、Nanog的表达变化。方法:收集分化不同时间点的拟胚体(EBs),检测三胚层分化基因以及全能性基因Oct4/Nanog的表达,并通过畸胎瘤组织切片的荧光染色分析Oct4的表达。结果:iPSCs获得的EB中内外三胚层分化基因表达的出现明显晚于hESCs来源的EB。不同于hESCs,iPSCs悬浮培养获得的EBs在体外培养18天未见内源性Oct4、Nanog基因表达的下调。未分化的iPSCs注射严重联合免疫缺陷(SCID)小鼠培养10周后获得的畸胎瘤中仍存在Oct4阳性的细胞,但iPS-#2中明显少于iPS-#5。结论:通过慢病毒方法获得的iPSCs虽然具有向三胚层分化的能力,但在分化过程中仍维持较高水平的全能性基因Oct4、Nanog的表达。     

Could co‐transplantation of iPS cells derived hepatocytes and MSCs cure end‐stage liver disease?

Orthotopic liver transplantation is, to date, the only proven effective treatment for end-stage liver disease. However, it suffers from lack of donors and immunorejection. Here, we speculate that co-transplantation of induced pluripotent stem (iPS) cells derived hepatocytes and mesenchymal stem cells (MSCs) may offer an alternative way to treat patients with end-stage liver disease. Recently, progress on iPS cells, homogeneous differentiation of hepatocyte-like cells from embryonic stem cells (ESCs), and paracrine effects by MSCs highlight the possibility. Safe, efficient and rapid generation of iPS cells has been reliably produced by several experimental laboratories. Methods for highly efficient and homogeneous differentiation of ESCs into functional hepatocytes have been established as well. Moreover, paracrine effects by MSCs have been proven to play an important role in liver regeneration and repair, and the effects can be used as an enhancer for engraftment. All of these remarkable developments lead to this hypothesis which may offer a novel therapeutic strategy for treatment of patients with end-stage liver disease, though some issues about safety and efficacy need to be further guaranteed.     

Artificial niche substrates for embryonic and induced pluripotent stem cell cultures

Stem cells possess the ability to self-renew and differentiate into other cell types. In vivo, stem cells reside in their own anatomic niches in a defined physiological environment, from which they are released to differentiate into a required cell type when deemed appropriate. While a resident within the niche, the stem cell receives signals that in turn maintain the cell in a pluripotent state. In addition, the niche also provides nourishment to the cell. Physically, the niche also serves to anchor the cell via various ECM components and cell-adhesion molecules. Therefore, in vitro models that replicate the in vivo niche will lead to a better understanding of stem cell fate and turnover. In turn, this will help inform attempts to culture stem cells in vitro on artificial niche-like substrates. In this review, we have highlighted recent studies describing artificial niche-like substrates used to culture embryonic and induced pluripotent stem cells in vitro.     

对比不同类型干细胞对于缺血性脑卒中治疗的研究进展

成人中枢神经系统存在着一定量的神经干细胞,其具有两大关键能力;自我更新和多向分化潜能。缺血性脑卒中是一种由于由脑血流的缺失或减少引起的脑动脉闭塞,进而导致脑组织梗死的脑血管疾病。虽然对于脑损伤的药物治疗已经取得了一定的成果,但目前以干细胞为基础的治疗方法仍成为了研究热点。无论是内源性神经干细胞还是外源性神经干细胞移植均可在脑损伤后向远端损伤区迁移并分化成新的神经细胞,从而在中枢神经系统疾病尤其是脑梗死后进行组织修复和功能恢复。因此在这篇综述中,我们主要探讨不同类型的干细胞对脑梗死介导的脑损伤的应用潜能,对比不同类型干细胞对缺血性脑卒中的治疗优缺点。