补肾方胚胎期干预预防子代成年大鼠IGT及其脂联素异常的实验研究

目的:研究中医补肾方在胚胎发育期干预能否对高脂饮食诱发的子代成年大鼠糖耐量低减(IGT)起到预防作用及其对血清脂联素的影响。方法:将孕鼠分为正常对照组、模型组、左归丸组、右归丸组、八珍汤组,于孕1 d¹9 d,正常对照组和模型组分别以生理盐水灌胃,各用药组分别以左归丸、右归丸、八珍汤灌胃。除正常对照组外,其余各组子鼠均于6 w龄开始高脂饮食。12 w后测各组子鼠空腹血糖(FBG)、糖负荷后2 h血糖(2 h BG)、血脂、血清脂联素(APN)。结果:与模型组比较,左归丸组2 h BG明显降低(P<0.05);3个用药组高密度脂蛋白水平均较模型组显著升高(P<0.01);左归丸组脂联素水平较模型组显著升高(P<0.01)。结论:大鼠胚胎期予补肾阴方左归丸干预有预防高脂饮食引发子代成年大鼠IGT的作用,可能与其对抗脂联素降低的作用有关。     

The therapeutic potential of phiC31 integrase as a gene therapy system

Introduction: The φC31 integrase system is a phage-derived system that offers the ability to integrate plasmid DNA into the chromosomes at a subset of endogenous preferred locations associated with robust gene expression. Recent progress highlights the unique advantages of this system for in vivo gene therapy and for use in stem cells.

Areas covered: The φC31 integrase system has been under development for ten years and has been demonstrated to be effective for integration of plasmids in a variety of tissues and organs for gene therapy in animal systems, as well as in isolated human cells. We focus on work with the φC31 integrase system during the past 12 – 18 months. This work has centered on a series of papers involving in vivo delivery of the integrase system to the liver and a variety of studies demonstrating the utility of the integrase system in stem cells.

Expert opinion: We conclude that the φC31 integrase system has significant potential for liver gene therapy, if effective DNA delivery methods for large mammals become available. The φC31 integrase system displays an outstanding fit for use in pluripotent stem cells, and this area is expected to be the subject of intense development.     

Embryonic stem cells as a treatment for macular degeneration

Introduction: Retinal degenerations are typically characterized by loss of highly differentiated cell types within the neurosensory retina, such as photoreceptors, or retinal pigment epithelium (RPE). RPE loss is the final common pathway in a number of degenerations including the leading cause of new blindness in the developed world: age-related macular degeneration (AMD).

Areas covered: This paper presents the pathophysiologic case for RPE transplantation with stem cell (SC)-derived tissue, a review of the preclinical data substantiating the hypothesis and the initial clinical trials safety data from early human trials.

Expert opinion: Targeting the RPE for transplantation with SC-derived tissue presents a reasonable therapeutic opportunity in a variety of important, otherwise untreatable, blinding conditions. Success of cellular replacement strategies is contingent on finding a viable source of replacement cells, establishing a safe technique for delivery and survival of transplanted cells within the host, restoration of normal retinal architecture and stabilization or improvement of vision.     

Feeder-free culture of human embryonic stem cell line BG01V/hOG using magnetic field-magnetic nanoparticles system

Purpose

Human embryonic stem (hES) cells are useful tools for regenerative medicine. Maintaining hES cells for research and clinical purposes remains a challenge. The hES cells have typically been grown on a mouse or human cell feeder layer, but these methods harbor potential health problems for the recipient. A culture system using magnetic field and iron oxide nanoparticles were previously demonstrated to sustain mouse embryonic stem cells in vitro. Now, by using the BG01v/hOG cell line, we could assess the effect of this culture system on the stemness of an embryonic stem cell of human origin.

Methods

Using a variant hES cell line, BG01V/hOG, expressing an emerald green fluorescent protein (EmGFP), we grown these cells in the presence of serum-free medium supplemented with magnetic nanoparticles functionalized with citrate. The cells were positioned over a circular magnet (4000 Gauss) and monitored daily by fluorescence microscopy.

Results

We discovered that hES cells can proliferate when labeled with magnetic nanoparticles and in the presence of a magnetic field without losing pluripotency.

Conclusion

These results establish an alternative method for maintaining hES cells which would minimize health concerns as well as label cells for subsequent clinical tracking.     

Human embryonic stem cells: Possibilities for human cell transplantation

Human embryonic stem (ES) cells serve as a potentially unlimited renewable source for cell transplantation targeted to treat several diseases. One advantage of embryonic stem (ES) cells over other stem cells under research is their apparently indefinite self‐renewal capacity if cultured appropriately, and their ready differentiation into various cell phenotypes of all three germ layers. To date, a number of studies have reported the derivation of specific functional derivatives from human ES cells in vitro. While there have been clinical trials of human embryonal carcinoma (EC) cell‐derived neurons in humans there has been no attempt as yet using human ES cell derivatives. However, the latter have been transplanted into recipient animals. In some cases ES‐derived cells were shown to undergo further maturation, displayed integration with host tissue and even ameliorated the disease condition in the animal model. Recently, it has been reported that human ES cells can be genetically manipulated. Such procedures could be used to direct differentiation to a specific cell type or to reduce graft rejections by the modification of immune responses. This review highlights some of the recent advances in the field and the challenges that lie ahead before clinical trials using ES‐derived cells can be contemplated.     

The safety of human pluripotent stem cells in clinical treatment

Abstract

Human pluripotent stem cells (hPSCs) have practically unlimited proliferation potential and a capability to differentiate into any cell type in the human body. Since the first derivation in 1998, they have been an attractive source of cells for regenerative medicine. Numerous ethical, technological, and regulatory complications have been hampering hPSC use in clinical applications. Human embryonic stem cells (ESCs), parthenogenetic human ESCs, human nuclear transfer ESCs, and induced pluripotent stem cells are four types of hPSCs that are different in many clinically relevant features such as propensity to epigenetic abnormalities, generation methods, and ability for development of autologous cell lines. Propensity to genetic mutations and tumorigenicity are common features of all pluripotent cells that complicate hPSC-based therapies. Several recent advances in methods of derivation, culturing, and monitoring of hPSCs have addressed many ethical concerns and technological challenges in development of clinical-grade hPSC lines. Generation of banks of such lines may be useful to minimize immune rejection of hPSC-derived allografts. In this review, we discuss different sources of hPSCs available at the moment, various safety risks associated with them, and possible solutions for successful use of hPSCs in the clinic. We also discuss ongoing clinical trials of hPSC-based treatments.     

A bioassay for Lafora disease and laforin glucan phosphatase activity

Objectives

Lafora disease is a rare yet invariably fatal form of progressive neurodegenerative epilepsy resulting from mutations in the phosphatase laforin. Several therapeutic options for Lafora disease patients are currently being explored, and these therapies would benefit from a biochemical means of assessing functional laforin activity following treatment. To date, only clinical outcomes such as decreases in seizure frequency and severity have been used to indicate success of epilepsy treatment. However, these qualitative measures exhibit variability and must be assessed over long periods of time. In this work, we detail a simple and sensitive bioassay that can be used for the detection of functional endogenous laforin from human and mouse tissue.

Design and methods

We generated antibodies capable of detecting and immunoprecipitating endogenous laforin. Following laforin immunoprecipitation, laforin activity was assessed via phosphatase assays using para-nitrophenylphosphate (pNPP) and a malachite green-based assay specific for glucan phosphatase activity.

Results

We found that antibody binding to laforin does not impede laforin activity. Furthermore, the malachite green-based glucan phosphatase assay used in conjunction with a rabbit polyclonal laforin antibody was capable of detecting endogenous laforin activity from human and mouse tissues. Importantly, this assay discriminated between laforin activity and other phosphatases.

Conclusions

The bioassay that we have developed utilizing laforin antibodies and an assay specific for glucan phosphatase activity could prove valuable in the rapid detection of functional laforin in patients to which novel Lafora disease therapies have been administered.     

酸性成纤维细胞生长因子与胚胎干细胞的造血分化

背景：有研究表明,在卵黄囊造血、胎肝造血和胚胎干细胞向造血干细胞分化过程中,酸性成纤维细胞生长因子可强烈表达。目的：探讨酸性成纤维细胞生长因子对小鼠胚胎干细胞造血分化的作用,在拟胚体培养阶段施加酸性成纤维细胞生长因子,验证酸性成纤维细胞生长因子对造血形成细胞产生的调控作用。方法：培养小鼠胚胎干细胞,将饲养层上生长状态良好的小鼠胚胎干细胞用胰酶消化成单个细胞后,利用悬滴法制备拟胚体,拟胚体继续悬浮培养,以1,2和50g／L酸性成纤维细胞生长因子分别培养3,5,7,9d,通过免疫荧光法检测胚胎干细胞与拟胚体中酸性成纤维细胞生长因子的表达,流式细胞术检测FIk-1^＋与CD133^＋阳性细胞率。结果与结论：酸性成纤维细胞生长因子在拟胚体中呈阳性表达。在5μg／L酸性成纤维细胞生长因子作用下,FIk-1^＋细胞随时间增加表达增加,CD133^＋细胞表达模式与FIk-1^＋细胞类似。在1μg／L时,FIk-1^＋细胞在7d时表达达到高峰,随后下降。CD133^＋细胞表达结果类似。而在2pg／L时,5d时FIk-1^＋细胞表达升高,随后下降,在9d时表达又增高。而CD133^＋细胞则总体呈现升高趋势。酸性成纤维细胞生长因子可促进FIk-1^＋与CD133^＋细胞的产生,证明酸性成纤维细胞生长因子能够有效促进拟胚体的扩增以及成血管血液干细胞的产生与增殖。