脂肪组织工程的新视角——脂肪间充质干细胞

文章对脂肪组织的来源，细胞的分离、纯化、培养及分子调控，细胞外基质的作用，细胞外微环境的影响进行综述。种子细胞的最佳来源是胚胎干细胞。研究表明过氧化物酶增殖体复合物在成脂分化中起主要调控作用，CCAT增强结合蛋白与ADD-1可启动和维持向脂肪方向分化作用，PPAR与配体结合激活脂肪发育过程中关键基因的转录，而AhR基因起负向调节作用。体外微环境培养中，起作用的是氧分压、pH值和黏附因子。     

人胎盘来源间充质干细胞移植促进肌腱移植物在骨隧道内的愈合

背景：研究表明,人胎盘来源间充质干细胞来源广泛,增殖能力强,其移植对腱-骨愈合有明显的促进作用。 目的：进一步验证人胎盘来源间充质干细胞对骨-肌腱结合处愈合的影响。 方法：采用贴壁分离筛选法获取人胎盘来源间充质干细胞。30只雄性SD大鼠随机分为2组各15只。建立大鼠骨-肌腱损伤模型,实验组在骨-肌腱结合面注入人胎盘来源间充质干细胞,对照组只注入生理盐水。 结果与结论：实验组人胎盘间充质干细胞移植后2,4,6周显微镜观察在腱骨界面有干细胞存在并有较多血管组织再生,并且有部分纤维软骨增生。在移植后4,6周实验组最大拔出载荷显著高于对照组(P < 0.05)。说明人胎盘来源充质干细胞可以促进骨-肌腱结合部的早期愈合,提高其生物力学强度。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：     

基底膜基质胶携带人脂肪组织来源间充质干细胞移植改善心肌梗死大鼠心脏功能

目的:应用基底膜基质胶(matrigel)携带人脂肪组织来源间充质干细胞(ADMSCs)在大鼠的心肌梗死部位注射,观察其对细胞存活的影响及改善心梗模型大鼠心脏功能的能力。方法:分离、培养、扩增人ADM-SCs,左冠状动脉前降支结扎法建立大鼠急性心肌梗死模型。将大鼠急性心肌梗死模型随机分为4组,对照组(PBS组)、matrigel组、PBS+ADMSCs组、matrigel+ADMSCs组,对移植4周后细胞的存活及心梗局部新生血管的密度进行测量,并利用心脏超声检测大鼠心脏功能。结果:与其它各组相比,matrigel+ADMSCs组的细胞4周存活细胞数量以及心肌梗死区域新生血管密度均显著提高,心脏超声结果也表明该组大鼠的心脏功能改善最为显著。结论:基底膜基质胶能够提高人脂肪组织来源间充质干细胞在大鼠心肌梗死部位的存活,有助于提高心肌梗死部位微血管生成并改善心肌梗死大鼠的心脏功能。     

血管内皮生长因子165基因促进人脂肪间充质干细胞的增殖

背景：目前自体脂肪移植已广泛运用于美容整形和修复创伤导致的软组织缺损的修复,有研究表明,移植后1年移植脂肪存活率为20%-80%,因此,在移植后的早期及时、充分的血供建立,对于移植脂肪的存活是非常重要的。目的：观察血管内皮生长因子165转染人脂肪间充质干细胞的增殖情况。方法：体外传代培养人脂肪间充质干细胞,将重组血管内皮生长因子165基因入腺病毒液和空病毒液转染至脂肪间充质干细胞内,分别设为实验组和对照组,另设正常培养的细胞为空白组。结果与结论：RT-PCR,Western blot,MTT检测显示,与对照组和空白组相比,实验组血管内皮生长因子165 mRNA和蛋白的表达及细胞增殖均增高(P < 0.05)。结果证实,腺病毒承载的血管内皮生长因子165基因转染脂肪间充质干细胞后不仅可以持续的表达目的蛋白,同时也能显著促进脂肪间充质干细胞的增殖。 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     

同种异体脂肪组织源性间质干细胞移植治疗大鼠急性心肌梗死

目的：建立体外分离扩增脂肪组织源性间质干细胞方法，并探讨同种异体脂肪干细胞移植治疗大鼠心肌梗死的效果及可行性。方法: 18只雄性SD大鼠随机分为假手术组、急性心肌梗死对照组（AMI组）及AMI+细胞移植组。分离大鼠腹部脂肪组织干细胞，体外扩增，BrdU标记后于结扎左冠状动脉前降支后1h移植入梗死心肌，移植后4周进行血流动力学检测心功能并取出心脏进行病理切片观察和免疫组织化学染色检测移植细胞在梗死心脏中的定居、存活情况。结果: 大鼠腹部脂肪组织可分离培养出大量间质干细胞。细胞移植治疗组左心室收缩压高于AMI对照组（P＜0.01），舒张末压显著降低（P＜0.01），左心室内压最大上升、下降速率明显加快（P＜0.05）；病理组织切片显示梗死边缘区心肌面毛细血管计数明显增加，梗死区心肌组织内及毛细血管壁中均可见移植标记细胞。结论: 脂肪组织可作为干细胞又一新的来源，同种异体脂肪干细胞移植治疗AMI有效、可行。     

不同部位来源的神经干细胞的研究进展

神经干细胞体外分离培养的成功,为神经系统疾病的细胞移植治疗提供了广阔的细胞来源。目前,从脑、脊髓、骨髓、脐血、脂肪组织和脐带等均可分离得到神经干细胞,并可诱导分化为其他细胞。但是,神经干细胞来源部位不同,其分离培养的方法及其特性均不同。本文就近年来不同部位来源的神经干细胞的研究进展作一综述。     

脂肪来源干细胞辅助下的面部年轻化治疗

背景：有研究表明脂肪来源干细胞具有组织修复能力,但将其应用于面部年轻化治疗中的报道较少。 目的：将原代脂肪来源干细胞辅助颗粒脂肪移植,联合颞部小切口除皱术应用于接受面部年轻化治疗的患者,观察该治疗方法的临床效果。 方法：回顾分析解放军沈阳军区总医院整形外在2009年6月至2011年8月的20例来院接受面部除皱治疗女性患者的资料。其中接受自体脂肪来源干细胞辅助治疗的患者10例设为治疗组,单纯接受除皱术患者10例设为对照组。采用皱纹评分的方法,结合VISIA专业皮肤图像分析系统对患者治疗后的斑点、毛孔、皱纹、纹理进行检测,对所得数据进行比较分析。 结果与结论：治疗后随访3-15个月,两组治疗前后皱纹评分差异无显著性意义,说明两组治疗患者在皱纹的改善方面效果没有明显区别。治疗前、后的VISIA皮肤检测结果显示,治疗组的毛孔和斑点改善率优于对照组(P < 0.05),纹理和皱纹改善率差异无显著性意义(P > 0.05)。证实,脂肪来源干细胞辅助下的面部年轻化治疗与单纯除皱疗法在面部年轻化治疗的除皱效果基本一致,但治疗后患者的皮肤毛孔、斑点改善效果明显更好。     

脂肪组织来源干细胞构建皮肤复合组织修复创面缺损

BACKGROUND: There is no clear understanding on the effects of subcutaneous fat and stem cells on wound healing. OBJECTIVE: To explore the therapeutic effects of skin composite prepared with adipose tissue-derived stem cells on skin defects. METHODS: Epidermal cells, fibroblasts, adipose tissue-derived stem cells as seed cells and bovine collagen gel as a scaffold were used to build a complex with a variety of cells. A 6-mm diameter circular skin defect was made on the both sides of the rat back. The right side as experimental side was implanted with an 8-mm diameter multilayer skin composite, and the left side (control side) was only treated with a simple dressing. RESULTS AND CONCLUSION: For the constructed multi-layer skin composite, the epidermal layer was continuously merged into the multi-layer, the fibroblasts evenly distributed in the corium layer, and lipid droplets existed in the fat layer in which the cells distributed uniformly. Cell aggregation was obviously observed at the junction of different layers. In the experimental side, the rate of wound healing, granulation tissue thickness, the thickness of dermis and the capillary density were significantly higher than those in the control side. Taken together, we can construct multilayer skin composites with a variety of cells as seed cells, such as epidermal cells, fibroblasts and adipose tissue-derived stem cells, and bovine collagen gel as a scaffold, which promote wound healing and increase the thickness of dermis.        

缺氧诱导因子1α基因转染脂肪干细胞与自体脂肪移植

背景：自体颗粒脂肪组织作为理想的填充材料用于美容与重建修复领域,但因其移植后组织大量被吸收,严重影响了远期效果。 目的：观察缺氧诱导因子1α基因转染脂肪干细胞对自体移植脂肪组织存活率的影响。 方法：取健康成年人吸脂术后的脂肪组织分离脂肪干细胞并行原代及传代培养,传至第3代,调整细胞浓度为1×109 L-1,经缺氧诱导因子1α基因转染后调整细胞浓度为1×1011 L-1备移植时使用;同时选用同一抽脂术后的脂肪组织颗粒并进行纯化,利用纤维蛋白胶的物理特性制备不同成分脂肪组织复合移植物,在20只裸鼠背部皮下随机分离3个腔隙,实验分为3组：基因修饰组移植经缺氧诱导因子1α基因修饰的脂肪干细胞+脂肪组织+纤维蛋白胶;基因未修饰组移植单纯脂肪干细胞+脂肪组织+纤维蛋白;生理盐水组移植生理盐水+脂肪组织+纤维蛋白。 结果与结论：移植后3个月和6个月,各组移植物血管密度比较,基因修饰组>基因未修饰组>生理盐水组,组间比较差异有显著性意义(P < 0.05);各组移植物脂肪细胞纤维坏死率比较,基因修饰组<基因未修饰组<生理盐水组,组间比较差异有显著性意义( P < 0.05);各组移植物脂肪质量保持率比较,基因修饰组>基因未修饰组>生理盐水组,组间比较差异有显著性意义(P < 0.05)。结果证实,缺氧诱导因子1α基因转染脂肪干细胞可促进移植脂肪组织局部的血管再生,促进脂肪细胞的成活,增加脂肪组织的质量保持率,减少脂肪移植术后的纤维坏死程度。     

人脂肪干细胞促进小鼠随意型皮瓣血管的新生

背景：脂肪干细胞是从脂肪组织中分离提取的一种具有多向分化潜能的干细胞,对缺血性疾病的治疗有积极作用。 目的：观察局部移植人来源脂肪干细胞对小鼠随意型皮瓣成活能力及血管新生效应的影响。 方法：体外经分离、培养及传代健康成人脂肪干细胞。于SPF小鼠背部设计蒂在头侧的随意型皮瓣设为实验组,随后于皮瓣蒂部、中部、远端分3次注射脂肪干细胞悬液、并设置以同法注射等量PBS的小鼠作对照组。移植后7 d,计算各组皮瓣成活率。移植后14 d,取皮瓣组织,随机作冰冻切片CD31免疫荧光染色,荧光显微镜下观察皮瓣组织微血管分布情况,并对CM-Dil标记的脂肪干细胞示踪;ELISA法检测皮瓣组织中血管内皮生长因子水平;Western blot法检测皮瓣组织中基质细胞衍生因子1蛋白的表达。 结果与结论：与对照组相比,实验组小鼠背部随意皮瓣成活率明显提高,皮瓣组织中微血管数目明显增多,血管内皮生长因子分泌水平明显升高,基质细胞衍生因子1蛋白表达明显增多(P < 0.05)。结果证实,人脂肪干细胞局部移植到随意型皮瓣后,可上调血管内皮生长因子和基质细胞衍生因子1的表达,促进皮瓣的血管新生。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：     

Adipose tissue engineering with naturally derived scaffolds and adipose-derived stem cells

A tissue-engineered adipose substitute would have numerous applications in plastic and reconstructive surgery. This work involves the characterization of the in vitro cellular response of primary human adipose-derived stem cells (ASC) to three dimensional, naturally derived scaffolds. To establish a more thorough understanding of the influence of the scaffold environment on ASC, we have designed several different soft tissue scaffolds composed of decellularized human placenta and crosslinked hyaluronan (XLHA). The cellular organization within the scaffolds was characterized using confocal microscopy. Adipogenic differentiation was induced and the ASC response was characterized in terms of glycerol-3-phosphate dehydrogenase (GPDH) activity and intracellular lipid accumulation. The results indicate that the scaffold environment impacts the ASC response and that the adipogenic differentiation of the ASC was augmented in the non-adhesive XLHA gels.     

Adipose tissue engineering in vivo with adipose-derived stem cells on naturally derived scaffolds

Placental decellular matrix (PDM) and PDM combined with cross-linked hyaluronan (XLHA) scaffolds, seeded with primary human adipose-derived stem cells (ASC), were investigated in a subcutaneous athymic mouse model. The in vivo response at 3 and 8 weeks was characterized using histological and immunohistochemical staining. Fibrous capsule formation was assessed and the relative number of adipocytes in each scaffold was quantified. Undifferentiated ASC were localized using immunostaining for human vimentin. Unilocular and multilocular adipocytes were identified by intracellular lipid accumulation. Staining for murine CD31 assessed implant vascularization. Both scaffolds macroscopically maintained their three-dimensional volume and supported mature adipocyte populations in vivo. There was evidence of implant integration and a host contribution to the adipogenic response. The results suggested that incorporating the XLHA had a positive effect in terms of angiogenesis and adipogenesis. Overall, the PDM and PDM with XLHA scaffolds showed great promise for adipose tissue regeneration.     

Protective effect of human adipose-derived stem cells transplanted to fat grafts against high-power laser therapy mediated fat tissue damage

Introduction

High Power Laser therapy (HPLT) can damage tissues due to its high skin absorption and side effects. The objective of this study was to determine the protective effect of human adipose-derived stem cells (hADSCs) against HPLT-mediated fat tissue damage after fat grafts in an in vivo study.

Clinical use of Dieletrophoresis separation for live Adipose derived stem cells

ABSTRACT: BACKGROUND: Microelectrode dieletrophoresis capture of live cells has been explored in animal and cellular models ex-vivo. Currently there is no clinical data available regarding the safety and efficacy of dielectrophoresis (DEP) buffers and microcurrent manipulation in humans, despite copious pre-clinical studies suggesting its safety. The purpose of this study was to determine if DEP isolation of SVF using minimal manipulation methods is safe and efficacious for use in humans using the hand lipotransfer model. METHODS: Autologous stromal vascular fraction cells (SVF) were obtained from lipoaspirate by collagenase digestion and centrifugation. The final mixture of live and dead cells was further processed using a custom DEP microelectrode array and microcurrent generator to isolate only live nucleated cells. Lipotransfer was completed using fat graft enhanced with either standard processed SVF (control) versus DEP filtered SVF (experimental). Spectral photography, ultrasound and biometric measurements were obtained at post operatively days 1, 4, 7, 14, 30, 60 and 90. RESULTS: The DEP filter was capable of increasing SVF viability counts from 74.3 +/- 2.0% to 94.7 +/- 2.1%. Surrogate markers of inflammation (temperature, soft tissue swelling, pain and diminished range of motion) were more profound on the control hand. Clinical improvement in hand appearance was appreciated in both hands, though the control hand exclusively sustained late phase erosive skin breaks on post operative day 7. No skin breaks were appreciated on the DEP-SVF treated hand. Early fat engraftment failure was noted on the control hand thenar web space at 3 months post surgery. DISCUSSION: No immediate hypersensitivity or adverse reaction was appreciated with the DEP-SVF treated hand. In fact, the control hand experienced skin disruption and mild superficial cellulitis, whereas the DEP-SVF hand did not experience this complication, suggesting a possible "protective" effect with DEP filtered SVF. Late ultrasound survey also revealed more frequent formation of oil cysts in the control hand, also suggesting greater risk of engraftment failure with standard lipotransfer. CONCLUSION: Clinical DEP appears safe and efficacious for human use. The DEP microelectrode array was found to be versatile and robust in efficiently isolating live SVF cells from dead cells and cellular debris in a time sensitive clinical setting.     

Amniotic fluid stem cells increase embryo survival following injury

Although amniotic fluid cells can differentiate into several mesenchymal lineages and have been proposed as a valuable therapeutic cell source, their ability to undergo terminal neuronal differentiation remains a cause of controversy. The aim of this study was to investigate the neuronal differentiation ability of the c-Kit-positive population from GFP-transgenic rat amniotic fluid, amniotic fluid stem (AFS) cells, and to assess how they affected injury response in avian embryos. AFS cells were found to express several neural stem/progenitor cell markers. However, no overt neuronal differentiation was apparent after either treatment with small molecules known to stimulate neuronal differentiation, attempts to differentiate AFS cell-derived embryoid body-like structures, or grafting AFS cells into environments known to support neuronal differentiation (organotypic rat hippocampal cultures, embryonic chick nervous system). Nonetheless, AFS cells significantly reduced hemorrhage and increased survival when grafted at the site of an extensive thoracic crush injury in E2.5 chick embryos. Increased embryo survival was induced neither by desmopressin treatment, which also reduced hemorrhage, nor by grafting other mesenchymal or neural cells, indicating a specific effect of AFS cells. This was found to be mediated by soluble factors in a transwell coculture model. Altogether, this study shows that AFS cells reduce tissue damage and increase survival in injured embryos, providing a potentially valuable tool as therapeutic agents for tissue repair, particularly prenatal/perinatal repair of defects diagnosed during gestation, but this effect is mediated via paracrine mechanisms rather than the ability of AFS cells to fully differentiate into neuronal cells.     

Adipose tissue engineering using mesenchymal stem cells attached to injectable PLGA spheres

The reconstruction of soft tissue defects remains a challenge in plastic and reconstructive surgery, and a real clinical need exists for an adequate solution. This study was undertaken in order to differentiate mesenchymal stem cells (MSCs) into adipocytes, and to then assess the possibility of constructing adipose tissue via the attachment of MSCs to injectable PLGA spheres. We also designed injectable PLGA spheres for scar-free transplantation. In this study, MSCs and adipo-MSCs (MSCs cultured in adipogenic medium for 7 days) were attached to PLGA spheres and cultured for 7 days, followed by injection into nude mice for 2 weeks. As a result, the difference between lipid accumulation in adipo-MSCs at 1 and 7 days was much higher in vitro than in the MSCs. Two weeks after injection, a massive amount of new tissue was formed in the APLGA group, whereas only a small amount was formed in the MPLGA group. We verified that the newly formed tissue originated from the injected MSCs via GFP testing, and confirmed that the created tissue was actual adipose tissue by oil red O staining and Western blot (PPAR(gamma) and C/EBP(alpha) were expressed only in APLGA groups). Therefore, this study presents an efficient model of adipose tissue engineering using MSCs and injectable PLGA spheres.     

脂肪间充质干细胞分化为内皮细胞并体外构建组织工程心脏瓣膜

背景：组织工程心脏瓣膜是利用组织工程技术将种子细胞种植于瓣膜支架上所构建的一种人工瓣膜,目前国内外研究主要集中于种子细胞来源及支架选择上。 目的：探讨人脂肪间充质干细胞体外向内皮细胞诱导分化后的细胞作为种子细胞,脱细胞猪主动脉瓣膜作为支架体外构建组织工程心脏瓣膜的可行性。 方法：利用吸脂术采集脂肪组织,分离、培养脂肪间充质干细胞,流式细胞仪鉴定细胞表型;免疫细胞化学方法及RT-PCR检测细胞分化标志物;应用Triton X-100联合胰蛋白酶的方法制备脱细胞猪主动脉瓣支架,将体外培养扩增的诱导分化后的内皮细胞种植于支架上构建组织工程心脏瓣膜,光镜及电镜下观察组织工程心脏瓣膜的组织学结构。 结果与结论：脂肪组织分离培养的脂肪间充质干细胞向内皮细胞诱导分化后表达CD31、CD34、CD144、Ⅷ因子和内皮型一氧化氮合成酶等内皮细胞特异性抗原;脱细胞猪主动脉瓣膜支架脱细胞完全,弹力纤维及胶原纤维保持完整;构建的组织工程心脏瓣膜可见支架上排列连续的单细胞层。提示脂肪间充质干细胞在体外向内皮细胞诱导分化后已初步具有内皮细胞功能,在脱细胞猪主动脉瓣膜支架上生长良好,可以在体外初步构建组织工程心脏瓣膜。     

Reconstruction of epidural fat with engineered adipose tissue from adipose derived stem cells and PLGA in the rabbit dorsal laminectomy model

Epidural fibrosis resulted from epidural fat destruction following laminectomy operation is regarded as a main cause of failed back surgery syndrome, which represents one of the most common complications in spine surgery. Up to now, the effectiveness of currently available treatments to prevent such a syndrome is quite limited. In the present study, we aimed to restore epidural fat using adipose tissue engineered from adipose derived stem cells (ASCs) in a rabbit dorsal laminectomy model. ASCs isolated from subcutaneous fat were first expanded to passage 3, seeded on porous poly(lactic-co-glycolic acid, PLGA) scaffold and then adipogenically induced for 7 days in?vitro to form cell-scaffold complex. Laminectomy sites were created at T13-L1 level in each animal. The laminectomy defect was implanted either with cell-scaffold complex or PLGA scaffold alone. Non-treated defect was also included as a control. The animals were subjected to MRI evaluation at 1, 12 and 24 weeks post-surgery, and sacrificed at 24 weeks for gross and histological observation. It was demonstrated by MRI evaluation that scar tissue of coarse and high density was formed within laminectomy site in PLGA alone and non-treated groups as early as 12 weeks. However, the defect implanted with engineered adipose had formed a continuous linear adipose tissue regenerated along the spinal cord at 24 weeks. Histologically, a distinct area of adipose tissue just overlaying the dura mater could be identified in cell-scaffold complex treated group at 24 weeks post-operation. Regeneration of epidural fat was further confirmed by positive Oil Red O staining. As to the defect treated with PLGA alone or left untreated, either fine or dense scar tissue adhering to the dura mater was observed. Moreover, we could track the implanted ASCs labeled by magnetic nanoparticles within epidural area for as long as four weeks by MRI detection. Thus, adipose tissue engineered from ASCs exhibited great potential in restoration of epidural fat to prevent formation of epidural fibrosis.