脂肪干细胞在软骨组织工程中的应用

软骨是最早应用组织工程技术成功构建的组织之一,但由于缺乏合适的软骨构建种子细胞,因此其发展相对落后。随着干细胞研究的兴起,脂肪干细胞（ASC）因其具有分布广泛、可利用细胞量大、取材容易等优点,为ASC作为种子细胞应用于组织工程研究提供了可能;但是ASC构建软骨组织的效果却不如骨髓间充质干细胞（BMSC）理想。因此ASC在软骨组织工程中的应用仍面临着诸多问题与挑战,其中最核心的问题是如何提高ASC成软骨的效率。为此从如何纯化脂肪来源细胞、尽可能保持其中干细胞的生物学特性并优化软骨诱导方案3个方面予以综述,为提高ASC成软骨的效率提供参考。     

骨髓间充质干细胞及其在骨/软骨缺损修复中的应用进展

间充质干细胞是一类多能干细胞，在胚胎形成过程中分化为骨、软骨、肌腱、肌肉、脂肪和髓基质等多种间充质组织。近年，研究者成功地分离到人和多种动物骨髓间充质干细胞并发现其在体外仍保持干细胞特性，能够诱导分化为成骨细胞、软骨细胞、成肌细胞和脂肪细胞等细胞系。动物实验表明，骨髓间充质干细胞能够修复具有临床意义的软骨缺损。其在肌腱缺损修复中的应用价值与巳初步得到证实。此外，由于具有多能性，间充质干细胞还是很好的基因载体。在创伤修复的基因治疗中有广阔的应用前景。     

脂肪干细胞在骨科基础研究中的新进展

背景：自脂肪来源干细胞被发现以来,培养传代及在支架材料上的生长能力就越来越受到骨科相关研究的关注。 目的：探讨脂肪来源干细胞的生物学特性及在骨科基础研究中的进展。 方法：由第一作者检索2001/2010 ISI Web of knowledge 数据库(网址http://www.isiknowledge.com)和PubMed 数据库(网址 http://www.ncbi.nlm.nih.gov/PubMed)有关脂肪来源干细胞培养特性和组织修复的相关文献并进行综合分析,检索词为“adipose derived stem cells,orthopaedic”。 结果与结论：脂肪来源干细胞具有与骨髓间充质干细胞相似的生物学特性及分化潜能,并且在骨骼、软骨、椎间盘、肌腱和韧带等组织的修复方面表现出良好的治疗效果。同时,脂肪来源干细胞在体内广泛分布,获取容易,为其在骨科相关疾病的修复治疗中奠定了良好的应用前景。     

腺病毒携带骨形态发生蛋白14基因转染脂肪干细胞修复损伤关节软骨

背景：关节软骨损伤后自我修复能力较弱,主要是由于其缺乏滋养血管并且细胞代谢缓慢等组织特性,目前的治疗方法都不能恢复软骨组织的原有功能,近年来软骨组织工程已引起了越来越多的关注。 目的：观察Ⅰ型胶原海绵支架搭载骨形态发生蛋白14基因转染脂肪干细胞修复兔膝关节软骨损伤的效果。 方法：取兔皮下脂肪组织分离培养脂肪干细胞,用腺病毒真核表达载体Ad-CMV-BMP-14-IRES-hrGFP-1转染脂肪干细胞。Ⅰ型胶原海绵支架搭载转染后的脂肪干细胞,待细胞吸附后对兔膝关节全层软骨缺损进行修复。术后12周取手术关节,从大体方面、组织学方面综合评估缺损修复状况。 结果与结论：骨形态发生蛋白14转染后的脂肪干细胞骨形态发生蛋白14和Ⅱ型胶原蛋白表达及Sox-9基因表达明显高于普通脂肪干细胞。术后12周,支架搭载经骨形态发生蛋白14转染的脂肪干细胞组软骨组织修复良好,平整光滑,光洁度、质地及颜色良好,交界区整合良好。支架搭载脂肪干细胞组软骨组织部分修复,有正常软骨光泽,质地与颜色接近正常,修复组织与正常软骨组织界限明显。单纯支架组几乎崩解塌陷,未见透明样软骨结构形成。结果可见腺病毒携带骨形态发生蛋白14基因转染后脂肪干细胞修复软骨缺损的能力有大幅提升。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：     

不同来源间充质干细胞生物学特性差异

背景：间充质干细胞在体内或体外特定的诱导条件下,可分化为软骨、肌肉、肌腱等。间充质干细胞进行的临床试验主要包括组织损伤修复,如骨、软骨、关节损伤的修复,心脏、肝脏、脊髓损伤和神经系统疾病的治疗。 目的：比较各种来源的间充质干细胞的生物学特性。 方法：检索1987到2015年PubMed数据库和中国知网数据库收录的与间充质干细胞来源,间充质干细胞生物学特性相关的文献。从细胞表面标记物,增殖、分化、迁移能力,以及功能方面进行分析总结,探讨了各种来源的间充质干细胞的优缺点。 结果与结论：不同来源的间充质干细胞的增殖潜力和表面标记物存在差异。不同组织来源的间充质干细胞免疫活性可能与间充质干细胞处于不同组织中的活化状态、种属差异、组织来源和培养条件的不同有关,从而导致不同源性间充干细胞免疫活性也不完全相同。深入认识影响不同组织来源间充质干细胞迁移的因素和机制,可以增强不同源性间充质干细胞靶向迁移的能力,提高其在创伤愈合、组织修复和再生中的治疗效率。  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     

骨软骨缺损修复中骨形态发生蛋白2的作用与应用

背景:骨软骨的缺损修复是目前骨科医生面对的一大挑战,当前的治疗手段达不到令人满意的效果,组织工程的发展为骨软骨缺损修复带来了新的希望。骨形态发生蛋白2是参与骨骼生长发育和修复的重要因子,具有良好的骨诱导作用,近些年研究发现骨形态发生蛋白2对软骨发育也有影响。目的:从骨形态发生蛋白2对骨和软骨2个方面的影响,探讨近年来骨形态发生蛋白2在骨软骨缺损修复中的研究进展。并通过总结骨形态发生蛋白2在各类骨缺损修复中的应用情况,为治疗骨软骨的缺损提供新的思路和策略。方法:在万方数据库和中国知网以“骨形态发生蛋白2,软骨细胞,软骨缺损,骨缺损,间充质干细胞,信号通路”为检索词;在PubMed数据库以“Bone morphogenetic protein 2,Chondrocytes,Cartilage injury,Bone injury,MSC,Signaling pathways”为检索词,检索2012-01-01/2022-07-01收录的有关骨软骨缺损修复中骨形态发生蛋白2的作用机制及在骨软骨组织工程中的应用研究。结果与结论:(1)骨形态发生蛋白2促进间充质干细胞软骨分化,并且能够维持软骨细...     

多孔丝素蛋白/羟基磷灰石复合脂肪间充质干细胞修复兔关节软骨及软骨下骨缺损

背景：丝素蛋白/羟基磷灰石是细胞立体培养的良好支架,是临床常用的骨缺损修复材料,具有良好的生物相容性。脂肪干细胞具有向骨及软骨细胞分化的潜能,适合骨软骨缺损修复。 目的：观察转化生长因子β1和胰岛素样生长因子1联合成软骨诱导脂肪干细胞与丝素蛋白/羟基磷灰石复合后修复兔关节软骨及软骨下骨缺损的效果。 方法：取新西兰大白兔56只,2只用于传代培养脂肪间充质干细胞,以3×109 L-1浓度接种到丝素蛋白/羟基磷灰石。其余54只新西兰大白兔,在股骨髁间制备软骨缺损模型,随机分为细胞复合材料组、单纯材料组和空白对照组,细胞复合材料组植入复合脂肪间充质干细胞的丝素蛋白/羟基磷灰石;单纯材料组植入丝素蛋白/羟基磷灰石;空白对照组不作任何植入。从大体、影像学、组织学观察比较缺损的修复情况。 结果与结论：12周时大体观察、CT、磁共振和组织学检查细胞材料复合组软骨及软骨下骨缺损区完全被软骨组织修复,修复组织与周围软骨色泽相近,支架材料基本吸收,未见明显退变和白细胞浸润,所有标本均未见丝素蛋白残留。单纯材料组缺损区缩小、部分修复,且呈纤维软骨样修复。空白对照组缺损无明显修复。提示复合脂肪间充质干细胞的丝素蛋白/羟基磷灰石修复兔关节软骨及软骨下骨缺损能力优于单纯丝素蛋白/羟基磷灰石材料。丝素蛋白/羟基磷灰石复合脂肪间充质干细胞可形成透明软骨修复动物膝关节全层软骨缺损,重建关节的解剖结构和功能,可作为新型骨软骨组织工程支架。     

骨形态发生蛋白2诱导慢性腱病大鼠肌腱干细胞体外成骨、成软骨分化

背景：目前临床对于慢性腱病缺乏有效的治疗手段,原因在于其发病机制至今尚未阐明。 目的：研究体外骨形态发生蛋白2对胶原酶诱导的大鼠慢性腱病模型髌腱来源肌腱干细胞的成骨、成软骨分化的作用。 方法：从大鼠慢性腱病模型的髌腱中分离培养出原代肌腱干细胞,传代培养至第3代细胞,行成骨、成脂、成软骨诱导分化鉴定其干细胞的特性。将肌腱干细胞(P3)单层培养至细胞融合,用重组人骨形态发生蛋白2干预。7 d后分别行茜素红染色,并行茜素红染色定量分析。将肌腱干细胞体外三维微球培养后分为2组,诱导组用重组人骨形态发生蛋白2干预,对照组不进行干预。21 d后三维微球行苏木精-伊红染色,阿利辛蓝染色以及Sox9和Ⅱ型胶原免疫组织化学染色。 结果与结论：慢性腱病大鼠来源原代肌腱干细胞体外培养呈克隆样集落生长,传代后细胞主要表现为多突的纺锤形和星形的扁平细胞,具有成纤维细胞样的特征。肌腱干细胞(P3)成脂诱导10 d,油红O染色阳性;成骨诱导7 d,茜素红染色阳性;成软骨诱导14 d,苏木精-伊红染色阳性可见软骨样细胞,Ⅱ型胶原免疫组化染色阳性。单层培养的肌腱干细胞用重组人骨形态发生蛋白2诱导7 d茜素红染色阳性,对照组为阴性,茜素红染色定量检测显示差异有显著性意义。重组人骨形态发生蛋白2诱导肌腱干细胞21 d,苏木精-伊红染色可见软骨样细胞形成、阿利辛蓝染色可见细胞内糖胺多糖沉积、Sox9和Ⅱ型胶原免疫组织化学染色均呈阳性。可见体外重组人骨形态发生蛋白2可以诱导慢性腱病来源的肌腱干细胞成骨、成软骨分化。这为进一步研究慢性腱病的发病机制提供了细胞生物学依据。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：     

自体脂肪间充质干细胞复合人脐带Wharton胶支架修复兔膝关节软骨缺损****◇

背景：脐带Wharton胶富含透明质酸,糖胺多糖及胶原等,成分与天然软骨细胞外基质类似,因此由人脐带提取的Wharton胶很可能是一种较为理想的软骨组织工程支架材料。 目的：评价自体脂肪间充质干细胞复合人脐带Wharton胶支架修复兔膝关节软骨缺损的效果。 方法：将终浓度为1010 L -1、成软骨方向诱导后的兔自体脂肪间充质干细胞与人脐带Wharton胶支架复合,继续培养1周构建组织工程软骨,对兔膝关节全层软骨缺损进行修复(实验组),并与单纯支架修复的对照组及空白组进行比较。术后3个月对修复组织行大体观察、组织学检测、糖胺多糖、总胶原定量检测及生物力学测定。 结果与结论：实验组的缺损多为透明软骨修复,对照组以纤维组织修复为主,空白组无明显组织修复。提示脂肪间充质干细胞作为软骨组织工程种子细胞具有可行性;实验构建的组织工程软骨能有效的修复关节软骨缺损,人脐带Wharton胶可作为软骨组织工程良好的支架材料。     

Stem-cell-capturing collagen scaffold promotes cardiac tissue regeneration

Stem cell based therapy is coming of age. Besides stem cell transplantation, it has been a goal to use native autologous stem cells for tissue regeneration. However, the recruitment of native autologous stem cells at the targeting site has not been sufficient which limits the clinical application of autologous stem cells. Biomaterials have been increasingly used in tissue repair. They not only serve as scaffolds for cell proliferation, differentiation, and also provide guidance for 3-D reestablishment. In this study, we have attempted to enrich autologous stem cells at the wound site through a stem-cell-capturing collagen scaffold by conjugating with a stem cell specific antibody. Sca-1 is a common surface marker of hematopoietic, cardiac and skeletal muscle stem cells. Due to the interaction of antibody and antigen, Sca-1 positive cells could be enriched to the functional collagen scaffold both in vitro and in vivo. When the functional collagen scaffold is transplanted into C57/BL6 mouse as a patch to repair a surgical heart defect, the regeneration of cardiomyocytes has been observed. Thus, the collagen scaffolds covalently conjugated with stem cell specific antibody could be an effective approach to promote tissue regeneration.     

组织工程种子细胞的研究进展

组织工程学近年来研究进展很快 ,目前采用组织工程技术建造的部分组织或器官已经开始进入或即将进入临床应用 ,如组织工程化皮肤已经实现商品化 ,软骨组织工程产品也已经进入临床前期实验阶段 ,在近年内即可进入临床应用[1～ 3 ,12 ] 。组织工程研究成功与否主要取决于以下三个关键性制约因素 :种子细胞、支架材料以及有助于细胞生长、分化的外在环境。其中获得足够数量、不引起免疫排斥反应且具有再生活力的种子细胞是开展组织工程研究的前提和基础。尽管目前种子细胞的研究仍面临众多挑战 ,但令人欣喜的是 ,随着干细胞体外分离、培养和扩…     

Adipose stromal cells-secreted neuroprotective media against neuronal apoptosis

Transplantation of pluripotent adipose stem/stromal cells (ASC) alleviates tissue damage and improves functional deficits in both stroke and cardiovascular disease animal models. Recent studies indicate that the primary mechanism of ASC-induced repair may not be directly related to tissue regeneration through differentiation, but rather through paracrine mechanisms provided by secreted pro-survival and repair-inducing trophic factors. In this study, we have found that ASC-conditioned medium (ASC-CM) potently protected cerebellar granule neurons (CGN) from apoptosis induced by serum and potassium deprivation. Neural cell protection was mostly attributable to activated caspase-3 and Akt-mediated neuroprotective pathway signaling. Specific neutralization of neurotrophic factor activity demonstrated that serum and potassium deprivation-induced Akt-mediated neuroprotection and caspase-3-dependent apoptosis were mainly modulated by IGF-1. These data suggest that of the many neuroprotective factors secreted by ASC, IGF-1 is the major factor that mediates protection against serum and potassium deprivation-induced CGN apoptosis. This study establishes a mechanistic basis supporting the therapeutic application of ASC for neurological disorders, specifically through paracrine support provided by trophic factor secretion.     

Therapeutic Application of Adipose Derived Stem Cells in Acute Myocardial Infarction: Lessons from Animal Models

The majority of patients survive an acute myocardial infarction (AMI). Their outcome is negatively influenced by post-AMI events, such as loss of viable cardiomyocytes due to a post-AMI inflammatory response, eventually resulting in heart failure and/or death. Recent pre-clinical animal studies indicate that mesenchymal stem cells derived from adipose tissue (ASC) are new promising candidates that may facilitate cardiovascular regeneration in the infarcted myocardium. In this review we have compared all animal studies in which ASC were used as a therapy post-AMI and have focused on aspects that might be important for future successful clinical application of ASC.     

Mesenchymal Stem/Progenitor Cells Derived from Articular Cartilage,Synovial Membrane and Synovial Fluid for Cartilage Regeneration: Current Status and Future Perspectives

Large articular cartilage defects remain an immense challenge in the field of regenerative medicine because of their poor intrinsic repair capacity. Currently, the available medical interventions can relieve clinical symptoms to some extent, but fail to repair the cartilaginous injuries with authentic hyaline cartilage. There has been a surge of interest in developing cell-based therapies, focused particularly on the use of mesenchymal stem/progenitor cells with or without scaffolds. Mesenchymal stem/progenitor cells are promising graft cells for tissue regeneration, but the most suitable source of cells for cartilage repair remains controversial. The tissue origin of mesenchymal stem/progenitor cells notably influences the biological properties and therapeutic potential. It is well known that mesenchymal stem/progenitor cells derived from synovial joint tissues exhibit superior chondrogenic ability compared with those derived from non-joint tissues; thus, these cell populations are considered ideal sources for cartilage regeneration. In addition to the progress in research and promising preclinical results, many important research questions must be answered before widespread success in cartilage regeneration is achieved. This review outlines the biology of stem/progenitor cells derived from the articular cartilage, the synovial membrane, and the synovial fluid, including their tissue distribution, function and biological characteristics. Furthermore, preclinical and clinical trials focusing on their applications for cartilage regeneration are summarized, and future research perspectives are discussed.     

Can hematopoietic stem cells be an alternative source for skin regeneration?

In the past few years, the plasticity of adult cells in several post-natal tissues has attracted special attention in regenerative medicine. Skin is the largest organ in the body. Adult skin consists of epidermis, dermis and appendages such as hair and glands that are linked to the epidermis but project deep into the dermal layer. Stem cell biology of skin has been a focus of increasing interest in current life science. Committed stem cells with a limited differentiation potential for regeneration and repair of epidermis have been known for decades. Recent studies further found that adult skin tissues contain cell populations with pluripotent characteristics. Multipotent stem cells from skin with and without hair follicles, both in epidermal and dermal tissues, can differentiate and generate multiple cell lineages. Especially, the hematopoietic system in epidermal and dermal tissue, like skin, may be a local, acceptable reservoir of various adult stem cell populations. Given their easy accessibility, such stem cells can provide an experimental model not only for skin biology but also for studying the epithelial–mesenchymal cell interactions of organs other than the skin. This review presents an overview of recent advances in research into skin repair and regeneration involving stem cells from epidermis, dermis, and bone marrow. In particular, we focus on the possible use of blood stem cells as an alternative resource for research advances in skin biology.     

Advances in Mesenchymal Stem Cell-based Strategies for Cartilage Repair and Regeneration

Significant research efforts have been undertaken in the last decade in the development of stem cell-based therapies for cartilage repair. Among the various stem cell sources, mesenchymal stem cells (MSCs) demonstrate great promise and clinical efficacy in cartilage regeneration. With a deeper understanding of stem cell biology, new therapeutics and new bioengineering approaches have emerged and showed potential for further developments. Of note, there has been a paradigm shift in applying MSCs for tissue regeneration from the use of stem cells for transplantation to the use of stem cell-derived matrix and secretome components as therapeutic tools and agents for cartilage regeneration. In this review, we will discuss the emerging role of MSCs in cartilage regeneration and the most recent advances in development of stem cell-based therapeutics for cartilage regeneration.     

Gene therapy for dentin regeneration with bone morphogenetic proteins

Recent advances in stem cell biology and gene therapy technology have provided the great potential of adult stem cells for therapeutic use in regeneration of lost tissue due to diseases including cancer, trauma, and even caries. Dental pulp tissues harbor mesenchymal stem/progenitor cells and have potential to regenerate and/or repair dentin-pulp complex after injury such as caries. There are two main methods, in vivo and ex vivo gene therapy. In in vivo gene therapy the healing potential of pulp tissue is enhanced by genes inducing dentin directly applied on the exposed/amputated dental pulp. In ex vivo gene therapy, pulp stem/progenitor cells transfected with some therapeutically proven genes to induce differentiation into odontoblasts which are transplanted on the exposed/amputated pulp. In the inflamed pulp under deep caries or trauma, possibly due to the limited supply of pulp stem/progenitor cells, it might be useful to apply cell-based ex vivo gene therapy compared to in vivo gene therapy. Before clinical use of ex vivo gene therapy for dentin regeneration in endodontics, there is a need for establishment of isolation, identification and expansion of the pulp stem cells. A safe and efficient gene delivery system also needs to be optimized. In this review we provide an overview of our current knowledge in the biology and function of adult pulp stem cells. This is followed by a discussion of the challenges of translating basic cellular and molecular biology of differentiation of pulp stem cells to safe and efficient gene therapy for dentin regeneration.     

Homing of endogenous stem/progenitor cells for in situ tissue regeneration: Promises, strategies, and translational perspectives

Stem cell-based therapy has been one of the best documented approaches in regenerative medicine, promising cures for a multitude of diseases and disorders. However, the ex vivo expansion of stem cells and their in vivo delivery are restricted by the limited availability of stem cell sources, the excessive cost of commercialization, and the anticipated difficulties of clinical translation and regulatory approval. An alternative to adoptively transferred stem cells are cell populations already present in a patient's body, including stem/progenitor cells, which can be actively attracted to sites of injury. This technique, known as endogenous cell homing, has the potential to provide new therapeutic options for in situ tissue regeneration. Such options would be less costly and complex than approaches that require substantial ex vivo cell manipulation and that use artificial vehicles for cell delivery. Tissue regeneration methods that rely on endogenous stem/progenitor cell homing, local tissue responses, and functional stimulation thus offer new insights into in vivo tissue engineering and hold great promise for the future of translational medicine. Although such methods that take advantage of the latent endogenous regenerative potential of the patient are promising for the repair of damaged tissue, they are in need of further experimental support before application in late-stage diseases or severe tissue injury. This review is not meant to be exhaustive but gives a brief outlook on the promises, strategies, and current applications of endogenous stem cell homing for in situ tissue regeneration, with particular emphasis placed upon pharmacological means based on cell-instructive scaffolds and release technology to direct cell mobilization and recruitment. In the future these exciting paradigms are likely to help reconcile the clinical and commercial pressures in regenerative medicine.