三维培养诱导人脂肪间充质干细胞微球的成软骨分化能力

背景：关节软骨损伤后修复结果不满意,需要新的手段,而脂肪间充质干细胞较适宜做种子细胞诱导软骨,然而怎么能够使诱导的软骨具有功能需要研究。 目的：采用三维培养体系诱导人脂肪间充质干细胞微球向软骨分化。 方法：无菌切取吸脂术后脂肪组织,分离培养人脂肪间充质干细胞,传至第3代进行流式细胞术分析,成骨成脂肪诱导等鉴定,同时也给予合适的培养条件用三维培养的方式向软骨细胞诱导,并行阿利辛蓝染色鉴定糖胺多糖的合成,苏木精-伊红染色进行组织学分析,免疫荧光检测Ⅱ型胶原表达,称质量测量软骨硬度。 结果与结论：分离的人脂肪间充质干细胞CD105,CD44,CD29均高表达,而 CD45,CD34低表达,并且成骨成脂诱导后细胞茜素红染色和油红O染色均为阳性。三维培养法诱导的软骨细胞可表达大量糖胺多糖及Ⅱ型胶原。结果证实,三维培养法诱导人脂肪间充质细胞向软骨分化后,具有软骨细胞的特性。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：     

大鼠来源滑膜间充质干细胞的成软骨分化

背景:相比其他组织来源的间充质干细胞,滑膜间充质干细胞有着较强的成软骨特性和克隆能力,因此将是软骨组织工程中最有前景的种子细胞之一。目的:培养及体外扩增SD大鼠滑膜间充质干细胞,鉴定其多向分化潜能及在添加生长因子后三维立体培养条件下的成软骨能力。方法:无菌条件下获取SD大鼠滑膜组织,Ⅰ型胶原酶消化法分离大鼠滑膜间充质干细胞。体外扩增、培养,取第3代滑膜间充质干细胞进行吉姆萨、生长曲线测定、成脂诱导、成骨诱导和三维条件下成软骨诱导,成软骨诱导21 d后通过甲苯胺蓝染色、Ⅱ型胶原免疫组化染色及RT-PCR对成软骨诱导后产物进行检测。结果与结论:获取的大鼠滑膜细胞具有间充质干细胞的特性,滑膜间充质干细胞在体外培养呈成纤维样形态,并维持着多向分化的能力。使用生长因子诱导软骨细胞21 d后,可见软骨样组织,蛋白聚糖和Ⅱ型胶原可以在甲苯胺蓝染色和Ⅱ型胶原免疫组化染色后被检测到。RT-PCR检测结果显示软骨诱导分化后细胞中Ⅱ型胶原和蛋白聚糖mRNA呈阳性表达。提示大鼠来源的滑膜间充质干细胞具有成软骨能力。     

三维动态培养构建注射型组织工程软骨远期修复效果的实验研究

目的三维诱导自体细胞软骨分化构建注射型组织工程软骨，探讨动物模型的远期修复效果。方法 分离培养兔自体骨髓间充质干细胞，分别三维动态诱导及二维平面培养诱导，诱导软骨细胞分化并鉴定，比较分化效果。分别收获两种方法诱导后的细胞，与蛋白胶混合制备注射型组织工程软骨，注射修复兔关节软骨缺损。随机设定三维动态培养组、二维平面培养组及空白对照组3组，24、48周后，观察大体和组织学形态，组织学评分比较远期效果。结果二维平面培养诱导后只有低水平的蛋白多糖沉积和Ⅱ型胶原等标志物表达，三维动态培养后的分化质量明显提高，大量表达蛋白多糖及Ⅱ型胶原。在动物模型中，三维动态培养组：24、48周后缺损基本修复，表面光滑坚韧，修复组织与周围软骨无界限，仍保持类透明软骨形态。二维平面培养组：24、48周后明显退化，失去软骨组织形态。空白对照组：无明显修复，缺损长期残留。结论三维动态培养显著改善自体MSC注射型组织工程软骨的修复效果，为提高关节软骨的微创修复提供新思路。     

骨髓间充质干细胞向软骨细胞分化过程中miR130α的表达

目的诱导骨髓间充质干细胞向软骨细胞分化,初步探索miR130a在骨髓间充质干细胞向软骨细胞分化过程中的调控作用。方法体外TGF-β1诱导骨髓间充质干细胞向软骨细胞分化,免疫荧光法和免疫组化染色鉴定Ⅱ型胶原,阿辛兰染色鉴定氨基葡聚糖。用Real-time PCR法检测细胞miR130a的表达。结果骨髓间充质干细胞在TGF-β1诱导下可分化为软骨细胞。培养7 d后,诱导培养组细胞miR130a表达的水平显著低于培养前的水平(P<0.05)。结论骨髓间充质干细胞体外诱导可以分化为软骨细胞,在向软骨细胞分化的早期,miR130a表达降低伴随着软骨细胞的分化,提示与软骨形成的过程有关。     

Ⅰ型胶原修饰聚乳酸聚乙醇酸微球支架上骨髓间充质干细胞的黏附和成骨分化

背景：组织工程骨成骨功能终末细胞需要骨髓间充质干细胞在体外加以诱导或在体内以基因转染等技术加以诱导。 目的：研究Ⅰ型胶原修饰的聚乳酸聚乙醇酸微球支架上骨髓间充质干细胞黏附和成骨分化的能力。 方法：制备聚乳酸聚乙醇酸微球支架,分离纯化雌性SD大鼠骨髓间充质干细胞。将培养至第3代骨髓间充质干细胞与未经处理的聚乳酸聚乙醇酸微球及Ⅰ型胶原修饰的聚乳酸聚乙醇酸微球共同培养14 d,观察细胞在不同支架表面的黏附生长。 结果：扫描电镜及FDA-PI染色发现,骨髓间充质干细胞可在聚乳酸聚乙醇酸微球支架上生长,而与未修饰的聚乳酸聚乙醇酸微球相比骨髓间充质干细胞更容易在Ⅰ型胶原修饰的聚乳酸聚乙醇酸微球上黏附增殖。Ⅰ型胶原修饰的聚乳酸聚乙醇酸微球有利于骨髓间充质干细胞的黏附、增殖,并且有一定诱导干细胞成骨分化的能力。     

以海藻酸盐及异种骨复合技术制备组织工程化骨及体内成骨(英文)

背景:海藻酸有相对温和的凝胶条件与良好的生物相容性,已广泛应用于生物组织工程。目的:采用海藻酸钠凝胶复合异种骨的方法,构建骨组织工程载体,观察载体中细胞的生物性能及体内成骨能力。方法:取2只2周龄新西兰兔的骨髓,以1×10-8mol/L重组人骨形态发生蛋白2诱导骨髓间充质干细胞。取诱导后第2代骨髓间充质干细胞接种于1%海藻酸钠凝胶中,培养4d苏木精-伊红染色观察凝胶中细胞形态。将第2代骨髓间充质干细胞分为单纯DMEM凝胶组和含1%海藻酸钠的DMEM凝胶组,分别培养7d后行骨形态发生蛋白2免疫组织化学染色观察。取24只裸鼠,随机分为2组,于两侧股部肌袋中分别植入骨髓间充质干细胞/海藻酸钠凝胶/牛松质骨复合体作为实验组,骨髓间充质干细胞/牛松质骨复合体作为对照组。术后2,4周后组织学观察复合体成骨情况,图像分析系统分析各组成骨或软骨的面积百分比。结果与结论:海藻酸钠凝胶中骨髓间充质干细胞形态饱满,细胞悬浮于凝胶中,可见细胞分裂和核分裂相。单纯DMEM凝胶组和含1%海藻酸钠的DMEM凝胶组免疫组织化学观察,细胞分裂增殖正常,伸出多种形态的突起,胞核大,核仁清晰。单纯DMEM凝胶组和含1%海藻酸钠的DMEM凝胶组的骨形态发生蛋白2表达阳性率差异无显著性意义(P0.05)。扫描电镜观察海藻酸钠凝胶均匀地复合于牛松质骨微孔中,不同平面均有细胞生长。动物实验显示术后2,4周实验组和对照组的成骨或软骨的面积百分比差异有显著性意义(P0.05)。提示以海藻酸钠凝胶/牛松质骨构建骨组织工程载体,合乎组织工程载体的超结构原理,能最大限度地承载细胞,生物性能好,对骨髓间充质干细胞增殖和成骨表型及相关的生物性能无不良影响,在体内成骨效率较高。     

骨髓间充质干细胞定向分化为软骨细胞

目的:体外定向诱导成人骨髓间充质干细胞(MSC)分化为单一的软骨细胞,探索体外成软骨的必要条件。方法: 采用淋巴细胞分离液密度梯度离心法分离骨髓,体外培养扩增,在较高的细胞密度下加入转化生长因子β1(TGF-β1),以微团培养(micromass culture)方式,诱导MSC分化为软骨细胞。HE染色观察细胞形态,阿新蓝、甲苯氨蓝染色检测软骨基质的分泌,免疫组织化学检测软骨特异性Ⅱ型胶原表达。结果: HE染色呈典型的细胞性软骨结构;阿新蓝染色阳性、甲苯氨蓝异染性;Ⅱ型胶原免疫组织化学检测阳性。结论: 成人骨髓MSC在体外分化为单一的软骨细胞需要高细胞密度、诱导因子TGF-β1及合适的培养条件。     

与软骨细胞共培养和条件培养液诱导骨髓间充质干细胞向软骨细胞分化的比较

背景：骨髓间充质干细胞体外转化很大程度上依赖于合适的培养条件。 目的：比较与软骨细胞共培养和条件培养液2种不同的诱导方案诱导骨髓间充质干细胞向软骨细胞分化的特点。 方法：分离培养大鼠骨髓间充质干细胞和耳软骨细胞,采用骨髓间充质干细胞与软骨细胞共培养及条件培养液诱导成软骨的方法,诱导骨髓间充质干细胞向软骨细胞分化。以MTT法及流式细胞仪检测细胞活性及周期,糖胺多糖、甲苯胺蓝以及免疫组化染色检测细胞生物学特性,以RT-PCR法检测诱导后的软骨细胞Ⅱ型胶原RNA表达情况。 结果与结论：采用共培养方式诱导的软骨细胞,其生物学特性与采用条件培养液诱导的软骨细胞相比,前者优于后者,如分泌糖胺多糖的能力以及基质分泌量均较高。提示共培养方式诱导的软骨细胞更接近正常软骨细胞,更有利于作为组织工程软骨的种子细胞。     

玻璃酸钠及胎盘间充质干细胞和诱导的软骨细胞膝关节腔内注射:修复膝骨关节炎

背景:胎盘间充质干细胞已被证实具有较强的增殖能力,能向神经细胞、血管内皮细胞、表皮细胞以及胰岛样细胞等诱导分化,但向软骨细胞诱导分化并修复膝骨关节的研究不多。目的:人胎盘间充质干细胞体外诱导软骨细胞膝关节腔内注射修复兔膝骨关节炎,并比较璃酸钠和胎盘间充质干细胞膝关节腔内注射的修复效果。方法:1选新西兰大白兔制作骨关节炎模型,左后肢膝关节炎造模后石膏固定5.5周,镜下观察关节软骨情况。2利用Ⅳ型胶原酶消化分离培养人胎盘间充质干细胞,流式细胞仪检测细胞表面标志物,证实为胎盘间充质干细胞。取第3代胎盘间充质干细胞进行实验,将胎盘间充质干细胞加入软骨诱导培养基向软骨细胞分化,倒置显微镜观察结果。3将大白兔随机分成玻璃酸钠膝关节腔内注射组、胎盘来源间充质干细胞膝关节腔内注射组和诱导软骨细胞膝关节腔内注射组,分别给予膝关节腔内注射,连续5周取膝关节软骨镜下观察,比较软骨修复情况。结果与结论:体外诱导培养的人胎盘间充质干细胞增殖形成大量贴壁细胞,贴壁细胞具有典型的间充质细胞形态;应用软骨诱导培养基培养后,细胞只保持微团,不继续增殖形成贴壁细胞,微团基部无贴壁细胞,显示人胎盘间充质干细胞可以分化为软骨细胞。苏木精-伊红染色镜下观察发现,各组兔膝关节软骨细胞均有修复,诱导软骨细胞膝关节腔内注射后兔膝关节软骨修复情况较好,优于玻璃酸钠和胎盘间充质干细胞膝关节腔内注射组。     

软骨细胞上清液诱导滑膜间充质干细胞微团培养成软骨

背景：滑膜间充质干细胞在体外具有多向分化的能力,有望成为软骨组织工程中治疗软骨缺损的种子细胞,在其向软骨细胞分化过程中,合适的生长因子起了重要作用。 目的：利用富含生长因子的软骨细胞上清液诱导滑膜间充质干细胞向软骨细胞分化,并对其鉴定。 方法：采用消化法分别获得SD大鼠滑膜间充质干细胞、软骨细胞。收集软骨细胞上清液离心、过滤冻存备用。培养滑膜间充质干细胞至第3代后离心成微团,并用软骨细胞上清液进行成软骨诱导分化,通过形态学观察、免疫组织化学法、RT-PCR检测进行鉴定。 结果与结论：滑膜间充质干细胞使用软骨细胞上清液成软骨诱导21 d后,微团可见似软骨样组织。免疫组化法进行Ⅱ型胶原鉴定,基质能被Ⅱ型胶原染色,细胞染色呈现棕黄色。RT-PCR结果显示诱导后的微团表达软骨特异性基因Ⅱ型胶原和蛋白聚糖。证实软骨细胞分泌的可溶性因子可以诱导大鼠滑膜间充质干细胞向软骨方向分化。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：     

Conditioned Media Enhance Osteogenic Differentiation on Poly(L-lactide-co-ε-caprolactone)/Hydroxyapatite Scaffolds and Chondrogenic Differentiation in Alginate

The biochemical factors that regulate cell proliferation and differentiation can provide a means of optimizing culture conditions to develop a tissue-engineered osteochondral construct. Thus, the objectives of this study were to determine the effects of chondrocyte conditioned medium (CM) on the osteogenic differentiation of mesenchymal stem cells (MSCs) cultured on poly(L-lactide-co-ε-caprolactone)/hydroxyapatite (PLA/PCL/HAP) scaffolds and to determine the effect of osteoblast CM on the chondrogenic differentiation of MSCs cultured in alginate. In addition, the biomaterial's effect on MSC differentiation was also investigated. MSCs were grown in two groups: (1) on porous PLA/PCL/HAP scaffolds in osteogenic differentiation medium or (2) encapsulated in alginate in chondrogenic differentiation medium. CM was taken from one group and administered to the 'opposite' group in volumetric concentrations of 25% or 50% at each medium change. The osteogenic group samples that were administered chondrocyte CM showed higher alkaline phosphatase activity than the controls that were not administered CM. Additionally, the cells that were given chondrocyte CM had higher osteocalcin and sialoprotein expression than the controls. Samples in the chondrogenic group that were administered osteoblast CM at a volumetric concentration of 50% produced more sGAG than the controls. The aggrecan and Sox9 expression was significantly higher in the samples given 50% CM as compared to the controls. The study also showed that culturing cells in alginate, without differentiation medium, can produce similar levels of differentiation as cells that were administered differentiation medium.     

Behavior of Human Mesenchymal Stem Cells in Fibrin-Based Vascular Tissue Engineering Constructs

A limitation of current tissue engineering vascular graft technology is the provision of an expandable, autologous cell source. By harnessing the multipotency of mesenchymal stem cells (MSC), it is hoped that functional vascular cells can be produced. To date, a range of 2D and 3D environments have been investigated for the manipulation of MSC differentiation pathways. To this end, this study aims to test the hypothesis that MSC seeded in various fibrin gel environments will exhibit evidence of a smooth muscle cell (SMC) phenotype. Initially, a range of cell-seeding densities were screened for 2D and 3D fibrin constructs, where it was observed that a seeding densities of 500,000 cells/mL facilitated gel compaction without degradation or loss in cell viability. Additionally, positive expression of CD49, CD73, CD105 markers and negative expression of hemopoietic stem cell-associated CD34 and CD45 indicated that MSC phenotype was retained within the fibrin gel. Nonetheless, a decrease in the gene expression of α-smooth cell actin and calponin was observed for MSC cultured in static 3D fibrin gels. Although a slight recovery was observed after 24 h mechanical stimulation, the fold-change remained significantly lower than that observed for cells cultured on 2D tissue culture plastic. While MSC differentiation toward a SMC appears possible in both 2D and 3D environments, scaffold architecture and mechanical stimulation undoubtedly play an important role in the creation of a functional SMC phenotype.     

Chondrocytes culture in three-dimensional porous alginate scaffolds enhanced cell proliferation, matrix synthesis and gene expression

For the limited availability of autologous chondrocytes, a cultured system for expansion in vitro until sufficient cells are obtained must be developed. These cells must maintain their chondrocyte phenotype in vitro as well as in vivo, following implantation to ensure that differentiated chondrocytes synthesize a normal hyaline cartilage matrix and not a fibro-cartilage matrix. This study uses porous three-dimensional (3-D) alginate scaffolds within a perfusion system to culture low-density (5 x 10(5) cells) primary porcine chondrocytes for 1-4 weeks to study their proliferation and differentiation. The results of RT-PCR reveal that most cells could maintain their differentiation state for up to 4 weeks of culturing. Chondrocytes proliferated to 3 x 10(7) cells after 4 weeks in culture. Alginate scaffolds induced the formation of chondrocyte clusters and stimulated the synthesis of matrix, which effects were evaluated using histology and electron microscopy. These findings demonstrate that culturing chondrocytes in alginate scaffolds may effectively prevent the dedifferentiation and improve autologous chondrocyte transplantation.     

成人骨髓间充质干细胞对造血干细胞体外增殖的影响

目的研究骨髓间充质干细胞（MSC）对脐带血（CB）CD34^＋细胞体外增殖和造血重建能力的影响。方法取人骨髓单个核细胞贴壁培养．梭形细胞完全融合后传代，用流式细胞仪检测免疫表型；将CBCD34^＋细胞接种到MSC或其他培养液中．比较不同培养条件对造血干细胞扩增能力、集落形成能力及黏附分子表达的影响。结果在加入IL-3的培养体系中．在MSC和细胞因子作用下，CD34^＋细胞扩增7d和14d后，有核细胞（NC）、CD34^＋细胞和CDl33^＋细胞数，实验组均显著多于对照组。CD34＋细胞在未加入IL-3的培养体系中培养8d后，实验组NC、CD34^＋细胞、CD34^＋CD38-细胞和造血祖细胞集落扩增倍数均显著高于对照组。扩增后CD34^＋细胞的ALCAM、VLA-α4、VLA-α5、VLA-β1、HCAM、PECAM和LFA-1表达较扩增前无显著变化。结论MSC可为造血干细胞（HSC）体外扩增提供适宜的微环境，有助于CD34^＋细胞体外增殖并抑制HSC分化，保持其造血重建潜能和归巢能力。     

Effect of 3D scaffold and dynamic culture condition on the global gene expression profile of mouse embryonic stem cells

We have previously demonstrated that mouse embryonic stem (ES) cells differentiated on three-dimensional (3D), highly porous, tantalum-based scaffolds (Cytomatrix™) have significantly higher hematopoietic differentiation efficiency than those cultured under conventional two-dimensional (2D) tissue culture conditions. In addition, ES cell-seeded scaffolds cultured inside spinner bioreactors showed further enhancement in hematopoiesis compared to static conditions. In the present study, we evaluated how these various biomaterial-based culture conditions, e.g. 2D vs. 3D scaffolds and static vs. dynamic, influence the global gene expression profile of differentiated ES cells. We report that compared to 2D tissue culture plates, cells differentiated on porous, Cytomatrix™ scaffolds possess significantly higher expression levels of extracellular matrix (ECM)-related genes, as well as genes that regulate cell growth, proliferation and differentiation. In addition, these differences in gene expression were more pronounced in 3D dynamic culture compared to 3D static culture. We report specific genes that are either uniquely expressed under each condition or are quantitatively regulated, i.e. over expressed or inhibited by a specific culture environment. We conclude that that biomaterial-based 3D cultures, especially under dynamic conditions, might favor efficient hematopoietic differentiation of ES cells by stimulating increased expression of specific ECM proteins, growth factors and cell adhesion related genes while significantly down-regulating genes that act to inhibit expression of these molecules.     

Matrix-mixed culture: new methodology for chondrocyte culture and preparation of cartilage transplants

For cartilage engineering a variety of biomaterials were applied for 3-dimensional chondrocyte embedding and transplantation. In order to find a suitable carrier for the in vitro culture of chondrocytes and the subsequent preparation of cartilage transplants we investigated the feasibility of a combination of the well-established matrices fibrin and alginate. In this work human articular chondrocytes were embedded and cultured either in alginate, a mixture of alginate and fibrin, or in a fibrin gel after the extraction of the alginate component (porous fibrin gel) over a period of 30 days. Histomorphological analysis, electron microscopy, and immunohistochemistry were performed to evaluate the phenotypic changes of the chondrocytes, as well as the quality of the newly formed cartilaginous matrix. Our experiments showed that a mixture of 0.6% alginate with 4.5% fibrin promoted sufficient chondrocyte proliferation and differentiation, resulting in the formation of a specific cartilage matrix. Alginate served as a temporary supportive matrix component during in vitro culture and can be easily removed prior to transplantation. The presented tissue engineering method on the basis of a mixed alginate-fibrin carrier offers the opportunity to create stable cartilage transplants for reconstructive surgery.     

降钙素基因相关肽诱导藻酸钙凝胶复合脂肪干细胞的成骨细胞分化

背景：降钙素基因相关肽已被证实具有诱导成骨细胞分化作用,但其是否可使三维培养下的脂肪干细胞向成骨细胞分化构建组织工程骨的相关报道少见。 目的：探讨外源性降钙素基因相关肽诱导兔脂肪干细胞复合藻酸钙凝胶三维培养成骨分化的可行性。 方法：取新西兰兔双侧腹股沟区皮下脂肪垫,Ⅰ型胶原酶消化离心贴壁法分离培养脂肪干细胞,取第3代与海藻酸钠混合制备凝胶,于24孔板分组培养：对照组加入含10^-2 mol/L β-甘油磷酸钠、10^-7 mol/L地塞米松、50 mg/L抗坏血酸、体积分数10%胎牛血清的DMEM/F-12骨诱导培养基,实验组在此基础上再加入1.5 µg/L降钙素基因相关肽进行诱导培养。于诱导不同时间点MTT法检测细胞增殖,RT-PCR法检测诱导细胞Ⅰ型胶原和骨钙素mRNA的表达,并检测碱性磷酸酶及钙离子浓度。 结果与结论：兔脂肪干细胞的增殖曲线呈“S”型,实验组诱导1,3,5,7,14,21 d的A值高于对照组(P < 0.05);诱导2周后两组细胞碱性磷酸酶、茜素红染色均阳性,但实验组钙结节较对照组明显增多。实验组诱导7,14 d的Ⅰ型胶原和骨钙素mRNA表达均强于对照组。实验组诱导1,2,3,4周的碱性磷酸酶活性及钙离子浓度均高于对照组(P< 0.05)。结果表明降钙素基因相关肽能诱导复合藻酸钙凝胶的脂肪干细胞向成骨细胞分化。     

The influence of physical structure and charge on neurite extension in a 3D hydrogel scaffold

Understanding neural cell differentiation and neurite extension in three-dimensional scaffolds is critical for neural tissue engineering. This study explores the structure-function relationship between a 3D hydrogel scaffold and neural cell process extension and examines the role of ambient charge on neurite extension in 3D scaffolds. A range of agarose hydrogel concentrations was used to generate varied gel physical structures and the corresponding neurite extension was examined. Agarose gel concentration and the corresponding pore radius are important physical properties that influence neural cell function. The average pore radii of the gels were determined while the gel was in the hydrated state and in two different dehydrated states. As the gel concentration was increased, the average pore radius decreased exponentially. Similarly, the length of neurites extended by E9 chick DRGs cultured in agarose gels depends on gel concentration. The polycationic polysaccharide chitosan and the polyanionic polysaccharide alginate were used to incorporate charge into the 3D hydrogel scaffold, and neural cell response to charge was studied. Chitosan and alginate were covalently bound to the agarose hydrogel backbone using the bi-functional coupling agent 1,1'carbonyldiimldazole. DRGs cultured in chitosan-coupled agarose gel exhibited a significant increase in neurite length compared to the unmodified agarose control. Conversely, the alginate-coupled agarose gels significantly inhibited neurite extension. This study demonstrates a strong, correlation between the ability of sensory ganglia to extend neurites in 3D gels and the hydrogel pore radius. In addition, our results demonstrate that charged biopolymers influence neurite extension in a polarity dependent manner.     

Cultured cell-derived extracellular matrix scaffolds for tissue engineering

Cell-derived extracellular matrix (ECM) scaffolds have received considerable interest for tissue engineering applications. In this study, ECM scaffolds derived from mesenchymal stem cell (MSC), chondrocyte, and fibroblast were prepared by culturing cells in a selectively removable poly(lactic-co-glycolic acid) (PLGA) template. These three types of ECM scaffolds were used for in vitro cultures of MSC and fibroblasts to examine their potential as scaffolds for cartilage and skin tissue engineering. The MSC were cultured in MSC- and chondrocyte-derived ECM scaffolds. The ECM scaffolds supported cell adhesion, promoted both cell proliferation and the production of ECM and demonstrated a stronger stimulatory effect on the chondrogenesis of MSC compared with a conventional pellet culture method. Histological and immunohistochemical staining indicated that cartilage-like tissues were regenerated after the MSC were cultured in ECM scaffolds. Fibroblasts were cultured in the fibroblast-derived ECM scaffolds. Fibroblasts proliferated and produced ECM to fill the pores and spaces in the scaffold. After 2 weeks of culture, a uniform multilayered tissue was generated with homogenously distributed fibroblasts. Cell-derived ECM scaffolds have been demonstrated to facilitate tissue regeneration and will be a useful tool for tissue engineering.