诱导干细胞向胰岛β样细胞分化的研究进展

β细胞替代治疗可能是目前唯一可以治愈1型糖尿病的方法,但可供移植的胰岛来源严重匮缺,阻碍了此疗法的临床应用。为此,调控干细胞分化为成熟的有功能的胰岛细胞成为近年来的研究热点。本文着重探讨了胰岛细胞发生发育的基因调控及几种生物活性分子体外诱导干细胞向胰岛β细胞分化的作用及其机理。     

干细胞诱导分化为产胰岛素细胞的研究进展

I型糖尿病(胰岛素依赖型糖尿病)主要是由于自身免疫反应导致胰岛β细胞损伤所致。目前,临床上主要通过口服降糖药物和胰岛素替代疗法等内科措施治疗I型糖尿病,但只能延缓疾病的发展,并不能彻底治愈。迄今为止,已有研究报道利用胚胎干细胞和成体干细胞成功诱导分化为产胰岛素细胞(IPCs),这给I型糖尿病的治疗带来了新的希望。从干细胞诱导成IPCs的诱导方法都是多阶段的,因干细胞来源不同,诱导所需时间从几天到几个月差异很大,不同诱导方法中所用诱导因子也有所不同,主要包括表皮生长因子、碱性成纤维细胞生长因子、激活素A、β细胞素、尼克酰胺、Exendin-4、肝细胞生长因子、胃泌素、葡萄糖和胎牛血清等。目前,尚无统一标准诱导方法可大量并稳定的获得IPCs,并使之分泌的胰岛素量可满足临床治疗。因此,在IPCs临床应用前,关于来源干细胞的选择、诱导方法和诱导所需因子的选用仍需进一步深入探讨。本文主要就干细胞诱导分化为产胰岛素细胞的研究进展进行了综述。     

成体干细胞向类许旺细胞诱导分化研究进展

周围神经损伤修复的黄金标准是自体神经移植,但由于遗留供区部位感觉功能障碍及可供移植神经数量有限,致使该项技术在临床上的应用受到限制,组织工程学的发展为此提供了一种新的解决途径.许旺细胞是周围神经组织工程重要的种子细胞,在神经再生过程中发挥重要作用,移植许旺细胞修复周围神经损伤有广阔的应用前景,但异体移植常面临免疫排斥反应,这些均导致了许旺细胞作为周围神经组织工程的种子细胞在临床应用中受到限制.近年来,随着对具有自我更新和多向分化潜能的间充质干细胞的深入研究,为组织工程化人工神经种子细胞的发展提出新的思路,本文将各种成体干细胞作为许旺细胞的替代细胞的研究进展作一综述.     

间充质干细胞诱导分化为胰岛β细胞的研究进展

间充质干细胞是一类具有多向分化潜能的成体干细胞,在体内外不仅可以被诱导分化为中胚层细胞,而且可以分化为内胚层和神经外胚层细胞。间充质干细胞易分离,体外可大量扩增,异体移植不引起免疫排斥反应,在细胞治疗和组织工程中具有广阔的应用前景。经过适当诱导,间充质干细胞可能成为胰岛β细胞的来源之一。就间充质干细胞的生物学性状和优势,以及诱导分化为胰岛β细胞的技术方法和发展趋势进行了综述。     

诱导体外培养的骨髓间充质干细胞向心肌样细胞的分化

选用Wistar大鼠分离骨髓间充质干细胞作体外培养及鉴定其表达抗原CD44、CDw90;采用10μmol／L 5-氮胞苷诱导第1代的骨髓间充质干细胞,于诱导后2、4周进行免疫细胞化学反应检测α-横纹肌肌动蛋白、肌钙蛋白T。证实体外培养的第1代骨髓间充质干细胞经5-氮胞苷诱导可分化为心肌样细胞,为指导体外诱导的心肌细胞应用于。临床提供一定的理论依据和技术手段。     

骨髓间充质干细胞分化为胰岛细胞治疗糖尿病

糖尿病已成为严重危害人类健康的疾病之一。目前,移植胰岛治疗糖尿病已初见疗效,但由于胰岛来源匮乏和免疫排斥反应而受阻。骨髓间充质干细胞(bonemarrowmesenchymalstemcells,BMMSCs)取材方便,容易进行体外分离、培养和纯化,且具有跨越分化潜能。若将自体BMMSCs诱导分化为胰岛细胞,可望解决细胞来源和免疫排除问题,实现糖尿病的自体细胞治疗。现对体外诱导BMMSCs分化为胰岛细胞治疗糖尿病的研究进展进行综述,并指出了存在问题和今后的研究方向。     

体外诱导骨髓间充质干细胞向肝细胞样细胞方向分化

探讨成纤维生长因子-2(FGF-2)在体外定向诱导大鼠骨髓间充质干细胞(BM-MSCs)向肝细胞样细胞分化的作用及量化关系。体外分离培养大鼠BM-MSCs,将第3代BM-MSCs采用不同剂量的FGF-2诱导。诱导后,在显微镜下观察细胞形态学的改变;用免疫细胞化学法检测白蛋白和CK19的分泌;Shiff染色法检测糖原的分泌。诱导后BM-MSCs由梭形向多角形、卵圆形方向变化,白蛋白、CK19和糖原12 d即有阳性表达,以后随着诱导时间的延长阳性率逐渐升高。20 ng/mL FGF-2诱导比10 ng/mL FGF-2诱导细胞白蛋白、CK19和糖原的表达量均多。20 ng/mL FGF-2具有较强的诱导BM-MSCs向肝细胞样细胞分化的能力。     

兔骨髓基质干细胞向血管内皮样细胞的诱导分化

目的:研究血管内皮细胞生长因子(VEGF)联合碱性成纤维细胞生长因子(bFGF)促进兔骨髓基质干细胞向血管内皮样细胞的定向诱导分化,为血管化组织工程骨研究提供实验基础.方法:采集2周龄兔后肢长骨骨髓,用全骨骨髓贴壁法进行原代培养,将获得的第2代骨髓基质干细胞以1× 105/mL密度接种于内皮细胞条件培养基(含10 μg/L VEGF,10 μg/L bFGF,10％胎牛血清的DMEM/F12培养液)进行体外诱导培养,对诱导2周的细胞进行细胞形态观察和表型、功能鉴定.结果:经血管内皮细胞条件培养基诱导2周后的细胞呈扁平形,多边形,表达血管内皮细胞特异性标志CD31、VWF因子,细胞具有吞噬DiI-Ac-LDL和摄取FITC-UEA-1的功能,诱导的细胞可在BD基质胶内形成管腔样结构.结论:血管内皮细胞生长因子联合碱性成纤维细胞生长因子可以成功诱导兔骨髓基质干细胞为血管内皮样细胞,有希望作为组织工程骨的血管化的种子细胞.     

间充质干细胞诱导分化为胰岛分泌细胞治疗1型糖尿病

糖尿病是严重危害人类健康的一类疾病,注射胰岛素和胰岛移植虽能用于治疗糖尿病,但都存在一定的局限性。大量研究表明,间充质干细胞（mesenchymal stem cell,MSC）可以在化学以及生物因子的作用下,或通过基因转染的方式在体外被诱导分化为胰岛素分泌细胞,且移植后对糖尿病鼠模型有一定降血糖效果,因而成为糖尿病治疗领域的研究热点。文章综述了不同来源的MSC诱导分化为胰岛分泌细胞（insulin—producing cells,IPC）的方法及诱导分化后用于治疗1型糖尿病的研究进展。     

干细胞诱导分化为胰岛素分泌细胞的研究现状

胰腺或胰岛细胞移植是目前治疗Ⅰ型糖尿病和部分Ⅱ型糖尿病效果最理想的方法,但因来源组织短缺及需要终生服用免疫抑制剂等问题限制了它的广泛应用.利用胰腺或胰腺外的多能干细胞产生胰岛样细胞有望克服上述问题而用于治疗糖尿病.本文就将干细胞诱导分化为胰岛样细胞中所用的重要的转录因子和可溶性诱导因子及其作用以及胰岛素分泌细胞的来源做一综述.     

胚胎干细胞诱导分化为雄性生殖细胞的研究进展

胚胎干细胞（embryonic stem cells,ES细胞）具有自我更新及无限分化潜能,理论上可以分化为生殖细胞。目前,在人及鼠中已有体外诱导ES细胞分化为成熟精子的报道。系统阐述影响ES细胞分化为雄性生殖细胞的内源性及外源性因素,并结合国内外最新研究进展总结其诱导分化方法,展望应用前景,期望为从事相关研究的学者提供参考。     

肿瘤干细胞研究进展

在过去的十年中,肿瘤干细胞（cancer stem cell／tumor—initiating cell,CSC／TIC）虽然受到广泛重视,但也是争论的焦点。如何正确认识CSCs假说,以及CSCs的生物学特点和CSCs的治疗应用这些问题都存在巨大的争议。该文对CSCS的起源、分离鉴定的方法,以及信号通路、微环境等对cSCS的调控关系,肿瘤的最佳治疗途径等问题进行综述。     

多能干细胞诱导分化为肾脏类器官的研究进展与挑战

用于分化为多种类型细胞的多能干细胞(PSC)体外培养技术已被广泛应用于生物学领域中.由PSC分化而来的肾脏类器官可基本还原生物体内肾脏的组织结构和部分功能,在肾脏疾病模型研究和药物筛选中有重要作用,继续改善肾脏类器官的结构、功能和成熟度将会对肾脏再生治疗提供极大的帮助.研究肾脏类器官的重点在于体外准确模拟体内肾脏的发育...     

成体干细胞及其在再生医学中的应用

成体干细胞研究的最主要目的就是有朝一日将其应用于临床疾病的治疗。随着对成体干细胞可塑性研究的不断深入和临床应用研究的不断扩展,人们对成体干细胞最终走向临床应用抱有越来越大的希望。本文就成体干细胞的可塑性及其在四种疾病中应用的基础研究进行探讨。     

Insulin-producing cells derived from stem cells: recent progress and future directions

Type 1 diabetes is characterized by the selective destruction of pancreatic beta-cells caused by an autoimmune attack. Type 2 diabetes is a more complex pathology which, in addition to beta-cell loss caused by apoptotic programs, includes beta-cell dedifferentiation and peripheric insulin resistance. beta-Cells are responsible for insulin production, storage and secretion in accordance to the demanding concentrations of glucose and fatty acids. The absence of insulin results in death and therefore diabetic patients require daily injections of the hormone for survival. However, they cannot avoid the appearance of secondary complications affecting the peripheral nerves as well as the eyes, kidneys and cardiovascular system. These afflictions are caused by the fact that external insulin injection does not mimic the tight control that pancreatic-derived insulin secretion exerts on the body's glycemia. Restoration of damaged beta-cells by transplantation from exogenous sources or by endocrine pancreas regeneration would be ideal therapeutic options. In this context, stem cells of both embryonic and adult origin (including beta-cell/islet progenitors) offer some interesting alternatives, taking into account the recent data indicating that these cells could be the building blocks from which insulin secreting cells could be generated in vitro under appropriate culture conditions. Although in many cases insulin-producing cells derived from stem cells have been shown to reverse experimentally induced diabetes in animal models, several concerns need to be solved before finding a definite medical application. These refer mainly to the obtainment of a cell population as similar as possible to pancreatic beta-cells, and to the problems related with the immune compatibility and tumor formation. This review will summarize the different approaches that have been used to obtain insulin-producing cells from embryonic and adult stem cells, and the main problems that hamper the clinical applications of this technology.     

干细胞的异常分化与肿瘤发生

干细胞是一类具有自我更新和多向分化潜能的细胞群体。越来越多的研究表明,干细胞异常分化可导致肿瘤。并且在肿瘤组织中存在部分细胞,它们具有干细胞的多种特性,被称为肿瘤干细胞(cancer stem cell,CSC)。肿瘤干细胞理论的提出,为肿瘤的治疗与研究提供了新的方向。本文综述了正常干细胞异常分化、肿瘤干细胞的存在和特性、肿瘤干细胞靶向治疗的前景及所面临的问题等方面的研究进展。     

造血干细胞研究进展

造血干细胞（hematopoietic stem cell,HSC）是成体干细胞研究领域的范式。对造血干细胞自我更新和不对称分裂分子遗传学机制的诠释,将不仅帮助理解成体干细胞“干性”维持的发育遗传学机制,也将对白血病干细胞和其他类型肿瘤干细胞的发育起源及开发针对肿瘤干细胞的靶向治疗模式产生深远的影响。     

Expression of Pdx-1 in bone marrow mesenchymal stem cells promotes differentiation of islet-like cells in vitro

Bone marrow mesenchymal stem cells (BMSCs) have the ability of self-renewal and multi-directional differentiation. Recent reports showed that BMSCs could differentiate into endocrine cells of pancreas. However, the differentiation is not efficient enough to produce insulin-producing cells for the future therapeutic use. Pdx-1 is a crucial regulator for pancreatic development. Therefore we constructed a eukaryotic expression vector containing Pdx-1 to determine the effect of Pdx-1 expression on differentiation of BMSCs in vitro. The results showed that BMSCs could self-assemble to form functional pancreatic islet-like structures after differentiation in vitro. The proportion of insulin-producing cells differentiated from Pdx-1⁺BMSCs was 28.23%±2.56%, higher than that from BMSCs transfected with vacant vector and Pdx-1 ⁻ BMSCs (7.23%±1.56% and 4.08%±2.69% respectively) by flow cytometry. Immunocytochemical examination also testified the expression of multiple β-cells-specific genes such as insulin, glucagons, somatostatin in differentiated BMSCs. The results also revealed that the expressions of genes mentioned above in Pdx-1⁺BMSCs were higher than that in Pdx-1⁻BMSCs, which was confirmed by Western blotting analysis and RT-PCR. Glucose-induced insulin secretion from Pdx-1⁺BMSCs in 5mmol/L and 25mmol/L glocuse was (56.61±4.82) μU/mL and (115.29±2.56) μU/mL respectively, which were much higher than those from Pdx-1⁻BMSCs((25.53±6.49) μU/mL and (53.26±7.56) μU/mL respectively). Grafted animals were able to maintain their body weight and survive for relatively longer periods of time than hyperglycemic sham-grafted controls, which demonstrated an overall beneficial effect of the grafted cells on the health of the animals. These findings thus suggested that exogenous expression of Pdx-1 should provide a promising approach for efficiently producing islet-like cells from BMSCs for the future therapeutic use in diabetic patients.     

基于造血干细胞为靶细胞的基因治疗

在基因治疗中,造血干细胞因为具有自我更新及分化为各种血细胞系的能力而成为一种很有吸引力的靶细胞。将外源目的基因导入造血干细胞,以纠正或补偿因基因缺陷和异常引起的疾病,特别是血液疾病已取得重要进展,例如:腺苷脱氨酶缺陷病、血友病、地中海贫血症及镰状细胞性贫血症等。而慢病毒以其转染效率高,能够感染非分裂期细胞的特点成为转染造血干细胞的最适合载体,本文就造血干细胞的特性、载体的选择及临床应用和基因治疗的安全性等方面作一综述。     

Recovering the osteoblastic differentiation potential of mesenchymal stem cells derived from diabetic rats by photobiomodulation therapy

Autologous cell-based therapy for bone regeneration might be impaired by diabetes mellitus (DM) due to the negative effects on mesenchymal stem cells (MSCs) differentiation. Strategies to recover their osteogenic potential could optimize the results. We aimed to evaluate the effect of photobiomodulation (PBM) therapy on osteoblast differentiation of rats with induced DM. Bone marrow MSCs of healthy and diabetic rats were isolated and differentiated into osteoblasts (OB and dOB, respectively). dOB were treated with PBM therapy every 72 hour (660 nm; 0.14 J; 20 mW; 0.714 W/cm², and 5 J/cm²). Cell morphology, viability, gene and protein expression of osteoblastic markers, alkaline phosphatase (ALP) activity, and the mineralized matrix production of dOB-PBM were compared to dOB. PBM therapy improved viability of dOB, increased the gene and protein expression of bone markers, the ALP activity and the mineralized matrix production. PBM therapy represents an innovative therapeutic approach to optimize the treatment of bone defects in diabetic patients.