人脂肪源性干细胞多潜能分化特性

目的原代分离培养人脂肪干细胞(ADSCs),探讨细胞增殖及多向分化,间充质干细胞相关特性。方法取人吸脂术的脂肪组织通过酶消化法分离培养ADSCs,观察细胞形态,MTT法检测细胞增殖活性,流式细胞术检测细胞周期和表面抗原的表达,用茜素红、甲苯胺蓝和油红O染色鉴定向骨、软骨及脂肪诱导分化。结果人ADSCs呈长梭形、旋涡状生长,传至第15代的ADSCs仍具较强的增殖能力,ADSCs具有干细胞特性,高表达标记CD90和CD44的间充质干细胞,不表达内皮细胞标记CD31,而CD49d低表达,CD106阴性。成骨诱导后可见钙结节形成并被茜素红染成紫红色,软骨诱导后分泌大量蛋白多糖,被甲苯胺蓝染成蓝色,成脂诱导后细胞内可见大量脂滴被油红O染色红色。结论人脂肪干细胞可分化成间充质干细胞,具有稳定增殖和成骨、成软骨和成脂等多向分化潜能。     

不同部位脂肪源性干细胞的生物学特性比较

背景：大鼠不同部位来源的脂肪源性干细胞在体外培养时的特性是否存在差异目前尚无定论。 目的：比较同一只大鼠不同部位来源的脂肪源性干细胞在体外培养时的生长特性和成脂诱导分化能力的差异。 方法：无菌操作下取F344大鼠腹股沟及腹腔大网膜脂肪组织各5 mL,Ⅰ型胶原酶酶解法分离出脂肪源性干细胞,细胞计数后进行体外培养,观察其形态特征和生长状态,MTT法测定不同部位细胞的倍增时间。取不同部位来源的第2代脂肪源性干细胞进行成脂诱导,诱导14 d进行油红O染色,观察不同部位来源的脂肪源性干细胞的成脂分化能力。 结果与结论：在同一只大鼠内脏大网膜脂肪获得的脂肪源性干细胞数目为(281±10)×107 L-1,明显多于腹股沟皮下脂肪的(85±5)×107 L-1(P < 0.01)。从内脏大网膜脂肪与腹股沟皮下脂肪获得的脂肪源性干细胞分别于第5,6天进入指数增长期;第9,10天到达平台期;倍增时间为50 h和60 h左右。传代后的细胞生长分化活跃,呈成纤维细胞样,成脂诱导后,大网膜组织来源的脂肪源性干细胞的成脂诱导分化率明显高于腹股沟组织来源的脂肪源性干细胞[(38.90±2.86)%,(35.30±3.29)%,P < 0.01]。可见同一只大鼠不同部位脂肪组织分离得到的脂肪源性干细胞数目不同,体外成脂诱导分化能力亦存在差异。     

脂肪基质干细胞和骨髓基质干细胞的体外分化能力

背景：脂肪基质干细胞和骨髓基质干细胞具有很多相似的生物学特性。 目的：比较脂肪基质干细胞和骨髓基质干细胞与受损PC12细胞分别共培养后定向分化能力的差异。 方法：分别分离培养脂肪组织来源和骨髓组织来源的基质干细胞,取第5代细胞进行实验,2种细胞分别与正常或受损PC12细胞培养上清液共培养,或仅单独培养。 结果与结论：脂肪基质干细胞和骨髓基质干细胞均表达较高水平的CD44和CD29,而后者表达的CD45、CD56在前者几乎未检测到。单独培养的2种细胞均表达较高水平的Nanog、Oct4、Sox2,不表达神经元特异性烯醇酶。其中经受损PC12细胞干预的2种细胞Nanog、Oct4、Sox2表达水平显著降低,而脂肪基质干细胞中神经元特异性烯醇酶阳性细胞数更多,提示受损PC12细胞对于脂肪基质干细胞可能具有更强的诱导分化作用。     

脂肪间充质干细胞神经向分化能力的应用及潜能

背景：近年来,大量文献证实脂肪间充质干细胞与骨髓间充质干细胞具有相同的特性、细胞表面标志,包括向成骨细胞、软骨细胞、成肌细胞、脂肪细胞和神经元样细胞分化的能力。 目的：综述脂肪间充质干细胞分离培养,分化等生物学特性及其治疗神经系统疾病的临床应用情况。 方法：由第一作者检索1989年1月至2012年1月 PubMed数据库中有关脂肪间充质干细胞的神经向分化能力及治疗神经系统疾病的文献,检索词为“mesenchymal stem cells, nervous system disease,stem cell therapy”。共检索到733篇文献,最终保留26篇进行归纳总结。 结果与结论：脂肪组织在人体内含量丰富,获得率高,且提取纯化后的细胞纯度高,活性大,扩增能力强,使脂肪间充质干细胞成为再生医学应用的理想种子细胞。最近研究指出脂肪间充质干细胞明显促进了神经损伤后的功能修复。但是,至今脂肪间充质干细胞发挥疗效的各种机制尚停留在探索性研究阶段,且其用于治疗神经系统疾病的有效性和安全性尚缺乏大量临床病例资料,从而制约其在临床的大力开展。     

脂肪干细胞诱导分化的现状及前景

背景：脂肪干细胞是由中胚层发育而来的多能干细胞,在特殊的生长因子和环境等诱导培养条件下,可以向不同的谱系分化。 目的：详细阐述脂肪干细胞诱导分化的条件及鉴定方法。 方法：应用计算机检索万方数据库及PubMed数据库2005至2014年10年间的文献,中文检索词为“脂肪干细胞,诱导,分化”;英文检索词为“adipose derived stem cells,differentiation”。依据纳入排除标准选择37篇文献进行归纳总结。 结果与结论：脂肪干细胞在抗坏血酸、胰岛素、地塞米松、转化生长因子β作用下可向软骨细胞分化;成脂诱导液的配方包括3-异丁基-1-甲基黄嘌呤(IBMX)、胰岛素、地塞米松、吲哚美辛;成骨分化常用的诱导剂包含地塞米松或维生素D3、抗坏血酸,β-甘油磷酸钠;碱性成纤维细胞生长因子、表皮生长因子及维生素B27可联合应用诱导脂肪干细胞成神经分化;向心肌细胞分化普遍应用的诱导因子是5-氮杂胞苷;血管内皮生长因子和碱性成纤维细胞生长因子共同作用可以诱导脂肪干细胞向血管内皮细胞分化。随着分子生物学和细胞生物学的迅速发展,脂肪干细胞的分化研究也会更加深入,在目前对脂肪干细胞诱导分化现象观察的基础上,应加强对其内在的分子机制及调控脂肪干细胞可塑性的基因和蛋白的研究。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

The effect of serial passaging on the proliferation and differentiation of bovine adipose-derived stem cells

Adipose-derived stem cells (ASCs) represent an excellent cell source for the development of regenerative therapies for a broad variety of tissue disorders. Commonly, in vitro expansion is necessary to obtain sufficient cell populations for research purposes and clinical applications. Although it has been demonstrated that human ASCs can maintain their adipogenic, chondrogenic and osteogenic potential in long-term culture (up to 15 passages), it is not guaranteed that a satisfactory level of differentiation is achievable in later passages. In this study, we investigated the self-renewal and multilineage differentiation capacity of bovine ASCs, isolated from the interdigital fat pad, and explored how serial passaging influences the cells. A proliferation study examined the changes in growth kinetics from passage 1 to 5, and multilineage (adipogenesis, chondrogenesis and osteogenesis) differentiation studies were conducted to compare the potential between passage 2 (P2) and passage 5 (P5). From the proliferation study, a statistically significant change in the doubling time did not appear until P5. In the differentiation study, both P2 and P5 ASCs could be stimulated to undergo multilineage differentiation under specific culturing conditions. However, adipogenic and chondrogenic cultures showed significantly lower levels of differentiation in the P5-induced cultures. In contrast, P5-induced osteogenic cultures had higher alkaline phosphatase enzyme activity than P2-induced cultures, suggesting an increase in the osteogenic response with serial passaging. Overall, bovine ASCs are capable of self-renewal and multilineage differentiation; however, long-term in vitro expansion has a negative effect on adipogenic and chondrogenic differentiation, while potentially favoring osteogenesis.     

人参皂苷Rb1对体外培养人脂肪干细胞增殖与成骨分化的影响

背景：脂肪干细胞成骨分化受多种因素的影响,中药成骨诱导活性因子在脂肪干细胞研究中有重要意义。 目的：观察人参皂苷Rb1在体外培养条件下对人脂肪干细胞增殖和成骨分化的影响。 方法：体外分离培养人脂肪干细胞,传至第3代后,按2×10³/孔接种至96孔板,分别加入0.5,1.0,2.0,4.0,6.0 μmol/L人参皂苷Rb1培养基200 μL进行培养;设立对照组,仅加入等量普通DMEM培养基。采用XTT比色法测定大鼠脂肪干细胞的生长增殖曲线。通过碱性磷酸酶试剂盒测定细胞碱性磷酸酶活性,放射免疫法检测骨钙素含量,茜素红染色观察钙化结节形成能力。 结果与结论：0.5 μmol/L人参皂苷Rb1可明显促进人脂肪干细胞增殖;随着人参皂苷Rb1浓度的增加,促细胞增殖活性降低,6.0 μmol/L人参皂苷Rb1表现为明显的抑制细胞增殖作用。人参皂苷Rb1呈剂量依赖性促进人脂肪干细胞碱性磷酸酶活性和骨钙素表达。4.0,6.0 μmol/L人参皂苷Rb1诱导钙化结节形成能力优于0.5,1.0和2.0 μmol/L人参皂苷Rb1,对照组人脂肪干细胞未见钙化结节形成。提示人参皂苷Rb1在一定浓度范围内对体外培养条件下的人脂肪干细胞具有促生长增殖作用,但在高浓度时,人参皂苷Rb1对人脂肪干细胞的成骨分化具有促进作用,因此可作为一种良好的成骨诱导活性因子。     

低氧时脂肪间充质干细胞如何向跟腱细胞分化

背景：脂肪间充质干细胞在跟腱组织工程再生领域越来越受到重视,研究其诱导分化的有利环境(氧体积分数)尤为必要。 目的：将脂肪间充质干细胞与跟腱细胞在不同氧体积分数条件下间接共培养,比较氧体积分数对脂肪间充质干细胞向跟腱细胞分化能力的影响。 方法：无菌条件下获取SD大鼠跟腱细胞。SD大鼠脂肪间充质干细胞直接购买,经培养传至第1代后,与跟腱细胞一起在常氧(体积分数20%)和低氧(体积分数2%)条件下经Transwell间接共培养体系共培养。在培养7,14和21 d,实时荧光定量PCR检测跟腱细胞的特异指标胶原蛋白Ⅰ、胶原蛋白Ⅲ,Tenomodulin,Thrombospondin-4,Scleraxis基因相对表达量,免疫荧光染色法检测胶原蛋白Ⅰ和Thrombospondin-4蛋白表达量。 结果与结论：脂肪间充质干细胞与跟腱细胞经间接共培养后,低氧组检测到的跟腱细胞的相关特异指标在基因和蛋白水平上表达水平均高于常氧组。提示氧体积分数可显著影响脂肪间充质干细胞向跟腱细胞分化的潜能,低氧是脂肪间充质干细胞向跟腱细胞分化的有利条件之一。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

人脂肪源干细胞分离培养及向成骨细胞的诱导分化

背景：脂肪源干细胞可分泌众多的免疫调节因子,不引起T细胞的细胞毒作用,并可通过调整T淋巴细胞的种类和数量。 目的：探讨人脂肪源干细胞在体外分离培养扩增的方法及向成骨细胞诱导分化的能力。 方法：以0.1%的Ⅰ型胶原酶通过组织消化的方法分离人脂肪组织中的干细胞,体外扩增培养至第2代后检测其表面抗原的表达,并在成骨诱导液中促进其向成骨细胞的分化,通过碱性磷酸酶染色、茜素红染色及对碱性磷酸酶的RT-PCR检测来明确其分化能力。 结果与结论：体外分离培养的脂肪源干细胞生长稳定,扩增速度快。流式细胞仪检测结果显示其高表达干细胞相关抗原。向成骨细胞诱导后经免疫组化染色可见矿化结节形成,RT-PCR检测发现碱性磷酸酶表达阳性。提示脂肪源干细胞在体外分离培养方法简单,扩增速度快,并具有定向分化的能力,是可靠的组织修复和细胞治疗的种子细胞来源。     

大鼠腹腔脂肪干细胞的分离培养及诱导成骨

背景：脂肪干细胞取材方便、增殖旺盛、具有多向分化潜能,有望取代骨髓间充质干细胞而成为新一代组织工程的种子细胞。然而,脂肪干细胞的分离培养仍存在诸多困难与不足。 目的：优化脂肪干细胞的分离培养方法,并鉴定其成骨分化潜能。 方法：选取200 g成年雌性大鼠1只,无菌环境下切取大鼠肾脏、子宫周围及腹后外侧白色脂肪组织,多次胶原酶消化法分离消化,低糖培养基培养脂肪干细胞,倒置显微镜下观察脂肪干细胞的形态变化及增殖能力。采用成骨诱导培养液对第3代细胞进行成骨诱导,并采用碱性磷酸酶、茜素红染色方法进行鉴定。 结果与结论：脂肪干细胞形态以长梭形为主,增殖活跃呈旋涡状生长。经成骨诱导10 d后,碱性磷酸酶染色为阳性;成骨诱导28 d后,茜素红染色阳性。提示采用多次酶消化法得到的大鼠腹腔源性脂肪干细胞在体外易于分离培养,可以稳定传代。在一定条件诱导下,可以向成骨细胞分化。采用以上方法进行脂肪干细胞的分离培养可以为组织工程提供大量、优质的种子细胞。     

脂肪干细胞的体外诱导与分化

背景：应用脂肪干细胞来作为组织工程的种子细胞是近年来组织工程研究中的一个活跃领域,大量的研究表明在不同的条件下脂肪干细胞可以向机体的不同组织分化。 目的：对国内外脂肪干细胞体外诱导分化的现状及新进展作一综述。 方法：应用计算机检索CNKI和PubMed数据库中2000-01/2010-10关于脂肪干细胞的文章,在标题和摘要中以“脂肪干细胞,体外分化潜能,种子细胞,转基因”或“Adipose-derived stem cells,cell differentiation in vitro,seeded cell,gene transfaction”为检索词进行检索。选择文章内容与脂肪干细胞体外分化有关者,同一领域文献则选择近期发表或发表在权威杂志文章。初检得到112篇文献,最终入选28篇文献进行综述。 结果与结论：脂肪干细胞是存在于脂肪组织中的具有高度自我更新能力和多向分化潜能的干细胞群体。它具有多向系分化潜能,除可以分化为间充质来源的脂肪、骨、软骨以及骨骼肌、心肌等细胞,也可诱导分化为来源于外胚层的神经细胞以及具有功能性的血管内皮细胞。此外脂肪干细胞还具有造血支持作用以及可被腺病毒等高度转染等优点,可以作为基因转移良好的靶细胞。     

脂肪源性干细胞向成纤维细胞的分化

目的 探讨脂肪源性干细胞（ADSCs）向成纤维细胞分化的可能,为解决皮肤组织工程种子细胞提供有效途径。方法 取健康成年SD大鼠10只,体重280～320 g,雌雄不限,麻醉、脱毛、消毒,于腹股沟处获取脂肪后进行ADSCs的体外分离、培养和传代,观察原代细胞的生长特点;取第3代细胞,成骨诱导后第16天行碱性磷酸酶（ALP）检测,成骨诱导后第23天行茜素红染色,成脂诱导后第12天行油红O染色;流式细胞术检测细胞表面标志;加入条件培养基向成纤维细胞诱导分化,于诱导后第2天、第4天、第6天、第8天摄片记录细胞形态变化过程,MTT检测各时相点的细胞活性;诱导后第6天和第8天行扫描电子显微镜检测;诱导后第8天行免疫细胞化学染色,检测成纤维细胞主要标志物波形蛋白（vimentin）的表达。结果 原代ADSCs呈长梭形贴壁生长,成骨诱导后可见ALP强阳性表达,茜素红染色可见红色矿化结节;成脂诱导后可见胞内红染脂滴聚集;流式细胞术检测显示,间充质干细胞相关标志物CD90阳性表达,造血干细胞标记物CD45呈阴性表达;ADSCs向成纤维细胞诱导后第2天可见形态开始改变,部分细胞漂浮;诱导后第4天细胞呈水滴形或短棒状;诱导后第6天细胞呈有突起的多边形或三角形混杂;诱导后第8天细胞拥挤并铺满瓶底,呈细长纤维状; MTT检测表明,诱导后第2天的细胞活性要显著低于对照组（P<0.01）;诱导后第4天、第6天和第8天细胞活性与对照组均无明显差异（P>0.05）;扫描电子显微镜检测可见,诱导后第6天细胞呈三角形,表面纤毛较多;诱导后第8天细胞呈细长纤维状,有小突起,表面纤毛密集;诱导后第8天绝大多数细胞vimentin呈阳性表达。结论 ADSCs在体外经诱导分化后可以具备成纤维细胞的形态特征;能表达成纤维细胞的标志蛋白。     

Endothelial differentiation of adipose-derived stem cells from elderly patients with cardiovascular disease

Adipose-derived stem cells (ASCs) possess significant therapeutic potential for tissue engineering and regeneration. This study investigates the endothelial differentiation and functional capacity of ASCs isolated from elderly patients. Isolation of ASCs from 53 patients (50-89 years) revealed that advanced age or comorbidity did not negatively impact stem cell harvest; rather, higher numbers were observed in older donors (>70 years) than in younger. ASCs cultured in endothelial growth medium-2 for up to 3 weeks formed cords upon Matrigel and demonstrated acetylated-low-density lipoprotein and lectin uptake. Further stimulation with vascular endothelial growth factor and shear stress upregulated endothelial cell-specific markers (CD31, von Willebrand factor, endothelial nitric oxide synthase, and VE-cadherin). Inhibition of the PI(3)K but not mitogen-activated protein kinase pathway blocked the observed endothelial differentiation. Shear stress promoted an anti-thrombogenic phenotype as demonstrated by production of tissue-plasminogen activator and nitric oxide, and inhibition of plasminogen activator inhibitor-1. Shear stress augmented integrin α(5)β(1) expression and subsequently increased attachment of differentiated ASCs to basement membrane components. Finally, ASCs seeded onto a decellularized vein graft resisted detachment despite application of shear force up to 9 dynes. These results suggest that (1) advanced age and comorbidity do not negatively impact isolation of ASCs, and (2) these stem cells retain significant capacity to acquire key endothelial cell traits throughout life. As such, adipose tissue is a practical source of autologous stem cells for vascular tissue engineering.     

A comparative study of proliferation and osteogenic differentiation of adipose-derived stem cells on akermanite and beta-TCP ceramics

This study investigated the in vitro effects of akermanite, a new kind of Ca-, Mg-, Si-containing bioceramic, on the attachment, proliferation and osteogenic differentiation of human adipose-derived stem cells (hASCs). Parallel comparison of the cellular behaviors of hASCs on the akermanite was made with those on beta-tricalcium phosphate (beta-TCP). Scanning electron microscope (SEM) observation and fluorescent DiO labeling were carried out to reveal the attachment and growth of hASCs on the two ceramic surfaces, while the quantitative assay of cell proliferation with time was detected by DNA assay. Osteogenic differentiation of hASCs cultured on the akermanite and beta-TCP was assayed by ALP expression and osteocalcin (OCN) deposition, which was further confirmed by Real-time PCR analysis for markers of osteogenic differentiation. It was shown that hASCs attached and spread well on the akermanite as those on beta-TCP, and similar proliferation behaviors of hASCs were observed on the two ceramics. Both of them exhibited good compatibility to hASCs with only minor cytotoxicity as compared with the tissue culture plates. Interestingly, the osteogenic differentiation of hASCs could be enhanced on the akermanite compared with that on the beta-TCP when the culture time was extended to approximately 10 days. Thus, it can be ascertained that akermanite ceramics may serve as a potential scaffold for bone tissue engineering.     

3种组织来源的间充质干细胞体外成骨能力的比较

目的比较成人骨髓间充质干细胞(BMSCs)、人脐带间充质干细胞(UC-MSCs)和人胎盘间充质干细胞(P-MSCs)的成骨能力。方法用含10%胎牛血清的DMEM/Ham's F-12培养液培养3种MSCs,CCK8法检测增殖能力,流式细胞仪鉴定3种细胞。碱性磷酸酶(ALP)和茜素红染色观察细胞经成骨诱导后成骨分化蛋白-ALP的分泌和矿化钙结节的沉积。实时荧光定量PCR(RT-q PCR)法检测MSCs骨再生相关基因的表达。Western blot方法检测MSCs成骨再生相关基因的蛋白表达。结果 MSCs在第3天进入对数增殖期。3种细胞的表面标志物阳性率:CD44、CD90和CD105均高于98%。3种MSCs成骨诱导9 d时,3种MSCs的实验组均表达大量成骨分化蛋白-ALP,成骨诱导18 d时3种MSCs均呈现较好的矿化能力;3种MSCs成骨诱导9 d时,实验组RUNX2和ALP基因显著性高表达(P0.05),成骨诱导18 d时,实验组RUNX2和骨钙素(OCN)亦显著性高表达(P0.05);3种MSCs成骨诱导9 d时,实验组均检测到RUNX2和ALP的蛋白表达;成骨诱导18 d时,实验组细胞亦检测到RUNX2和OCN的蛋白表达。结论 UC-MSCs和P-MSCs具有良好的成骨分化能力,有望作为骨组织工程的种子细胞用于治疗骨缺损。     

Neuronal differentiation potential of human adipose-derived mesenchymal stem cells

Adult mesenchymal stem cells derived from adipose tissue (A-MSC) have the capacity to differentiate in vitro into mesenchymal as well as endodermal and ectodermal cell lineages. We investigated the neuronal differentiation potential of human A-MSC with a protocol which included sphere formation and sequential culture in brain-derived neurotrophic factor (BDNF) and retinoic acid (RA). After 30 days, about 57% A-MSC showed morphological, immunocytochemical and electrophysiological evidence of initial neuronal differentiation. In fact, A-MSC displayed elongated shape with protrusion of two or three cellular processes, selectively expressed nestin and neuronal molecules (including GABA receptor and tyroxine hydroxilase) in the absence of glial phenotypic markers. Differentiated cells showed negative membrane potential (-60 mV), delayed rectifier potassium currents and TTX-sensitive sodium currents. Such changes were stable for at least 7 days after removal of differentiation medium. In view of these results and the easy availability of adipose tissue, A-MSC may be a ready source of adult MSC with neuronal differentiation potential, an useful tool to treat neurodegenerative diseases.     

Chondrogenic differentiation of adipose-derived adult stem cells in agarose, alginate, and gelatin scaffolds

The differentiation and growth of adult stem cells within engineered tissue constructs are hypothesized to be influenced by cell-biomaterial interactions. In this study, we compared the chondrogenic differentiation of human adipose-derived adult stem (hADAS) cells seeded in alginate and agarose hydrogels, and porous gelatin scaffolds (Surgifoam), as well as the functional properties of tissue engineered cartilage constructs. Chondrogenic media containing transforming growth factor beta 1 significantly increased the rates of protein and proteoglycan synthesis as well as the content of DNA, sulfated glycosaminoglycans, and hydroxyproline of engineered constructs as compared to control conditions. Furthermore, chondrogenic culture conditions resulted in 86%, and 160% increases ( p < 0.05 ) in the equilibrium compressive and shear moduli of the gelatin scaffolds, although they did not affect the mechanical properties of the hydrogels over 28 days in culture. Cells encapsulated in the hydrogels exhibited a spherical cellular morphology, while cells in the gelatin scaffolds showed a more polygonal shape; however, this difference did not appear to hinder the chondrogenic differentiation of the cells. Furthermore, the equilibrium compressive and shear moduli of the gelatin scaffolds were comparable to agarose by day 28. Our results also indicated that increases in the shear moduli were significantly associated with increases in S-GAG content ( R2 = 0.36, p < 0.05 ) and with the interaction between S-GAG and hydroxyproline ( R2 = 0.34, p < 0.05 ). The findings of this study suggest that various biomaterials support the chondrogenic differentiation of hADAS cells, and that manipulating the composition of these tissue engineered constructs may have significant effects on their mechanical properties.     

The differentiation capacity of Clara cells isolated from the lungs of rabbits

The purpose of our studies was to determine the growth and differentiation potential of Clara cells isolated from rabbit lungs. The Clara cell preparations were enriched (80 to 85%) by density gradient-elutriation procedures and then were inoculated into rat tracheas denuded of their own epithelium. These tracheas then were transplanted subcutaneously on the backs of nude mice. For purposes of comparison, other denuded tracheas were inoculated with mixed epithelial cells obtained from rabbit tracheas by enzymatic procedures. Control tracheas were inoculated with cell-free media. At 2, 4, and 14 weeks after transplantation, the tracheal grafts were removed from the recipient nude mice and examined by light and electron microscopy. Tracheal grafts not receiving cell inocula contained no epithelial lining, and the tracheal lumens were filled with loose connective tissue. Tracheas inoculated with 2 X 10(4) mixed tracheal cells showed a columnar, pseudostratified epithelium composed of five cell types: (a) poorly-differentiated cells, (b) ciliated cells, (c) mucous cells, (d) Clara-like cells, and (e) typical basal cells. A very different epithelium was established in tracheas repopulated with Clara cell isolates. This epithelium, at all time points examined, was cuboidal, single layered (never pseudostratified), and lacked basal cells. The tracheal lumens were lined with ciliated and nonciliated cells. The latter showed typical features of mature Clara cells (i.e., electron dense granules and smooth endoplasmic reticulum). At 14 weeks, the same two cell types were present, and often they were located on ridges and furrows of the tracheal walls. Mixed tracheal cells inoculated into denuded tracheas gave rise to a normal-appearing pseudostratified mucociliary epithelium, whereas the Clara cells inoculated under identical conditions gave rise to a low cuboidal epithelium resembling that seen in normal bronchioles. Establishment of these two types of epithelial linings occurred in the presence of the same mesenchymal components. Thus, we conclude that Clara cells have considerable self-renewal capacity, and their differentiation potential appears to be quite narrow.     

不同代次大鼠脂肪间充质干细胞增殖及成神经球的能力比较

背景：脂肪间充质干细胞是一组具有多向分化潜能的干细胞,体外在一定条件下可分化为神经干细胞。 目的：观察不同代次大鼠脂肪间充质干细胞体外培养增殖能力及诱导成神经球的潜力。 方法：取SD大鼠脂肪体外分离培养出脂肪间充质干细胞并传代扩增,分别在P3、P6、P10、P20时观察其形态学变化、测定增殖速度。流式细胞仪检测定不同代次细胞表型及细胞周期。将脂肪间充质干细胞诱导为神经球,计数成神经球率。 结果与结论：脂肪间充质干细胞主要呈长梭形,不同代次的脂肪间充质干细胞均具有很强的体外增殖能力;除P3细胞其他代次细胞均高表达CD29、CD44、CD73,低表达CD45、CD34。细胞周期中G0/G1期细胞所占比例P3为93.4%、P6为92.7%、P10为92.4%、P20为86.0%。P6、P10诱导成神经球率均显著高于P20(P < 0.05),P3细胞较难诱导成神经球。提示以脂肪间充质干细胞作为种子细胞时,应注意选择适宜的扩增代数,以便在获得足够纯度细胞的同时保留细胞最佳的分化潜力。中国组织工程研究杂志出版内容重点：干细胞;骨髓干细胞;造血干细胞;脂肪干细胞;肿瘤干细胞;胚胎干细胞;脐带脐血干细胞;干细胞诱导;干细胞分化;组织工程全文链接：     

Chondrocytic differentiation of human adipose-derived adult stem cells in elastin-like polypeptide

Human adipose derived adult stem (hADAS) cells have the ability to differentiate into a chondrogenic phenotype in three-dimensional culture and media containing dexamethasone and TGF-beta. The current study examined the potential of a genetically engineered elastin-like polypeptide (ELP) to promote the chondrocytic differentiation of hADAS cells without exogenous chondrogenic supplements. hADAS cells were cultured in ELP hydrogels in either chondrogenic or standard medium at 5% O2 for up to 2 weeks. By day 14, constructs cultured in either medium exhibited significant increases in sulfated glycosaminoglycan (up to 100%) and collagen contents (up to 420%). Immunolabeling confirmed that the matrix formed consisted mainly of type II and not type I collagen. The composition of the constructs cultured in either medium did not differ significantly. To assess the effect of oxygen tension on the differentiation of the above constructs, samples were cultured in standard medium at either 5% or 20% O2 for 7 days and their gene expression profile was evaluated using real time RT-PCR. In both cases, the hADAS-ELP constructs upregulated SOX9 and type II collagen gene expression, while type I collagen was downregulated. However, constructs cultured in 20% O2 highly upregulated type X collagen, which was not detected in the 5% O2 cultures. The study suggests that ELP can promote chondrogenesis for hADAS cells in the absence of exogenous TGF-beta1 and dexamethasone, especially under low oxygen tension conditions.