Isolation, culture and chondrogenic differentiation of canine adipose tissue- and bone marrow-derived mesenchymal stem cells–a comparative study

In the dog, mesenchymal stem cells (MSCs) have been shown to reside in the bone marrow (bone marrow-derived mesenchymal stem cells: BM-MSCs) as well as in the adipose tissue (adipose tissue-derived stem cells: ADSCs). Potential application fields for these multipotent MSCs in small animal practice are joint diseases as MSCs of both sources have shown to possess chondrogenic differentiation ability. However, it is not clear whether the chondrogenic differentiation potential of cells of these two distinct tissues is truly equal. Therefore, we compared MSCs of both origins in this study in terms of their chondrogenic differentiation ability and suitability for clinical application. BM-MSCs harvested from the femoral neck and ADSCs from intra-abdominal fat tissue were examined for their morphology, population doubling time (PDT) and CD90 surface antigen expression. RT-PCR served to assess expression of pluripotency marker Oct4 and early differentiation marker genes. Chondrogenic differentiation ability was compared and validated using histochemistry, transmission electron microscopy (TEM) and quantitative RT-PCR. Both cell populations presented a highly similar morphology and marker expression in an undifferentiated stage except that freshly isolated ADSCs demonstrated a significantly faster PDT than BM-MSCs. In contrast, BM-MSCs revealed a morphological superior cartilage formation by the production of a more abundant and structured hyaline matrix and higher expression of lineage specific genes under the applied standard differentiation protocol. However, further investigations are necessary in order to find out if chondrogenic differentiation can be improved in canine ADSCs using different protocols and/or supplements.     

Impact of source tissue and ex vivo expansion on the characterization of goat mesenchymal stem cells

Background: There is considerable interest in using goats as models for genetically engineering dairy animals and also for using stem cells as therapeutics for bone and cartilage repair. Mesenchymal stem cells(MSCs) have been isolated and characterized from various species, but are poorly characterized in goats.Results: Goat MSCs isolated from bone marrow(BM-MSCs) and adipose tissue(ASCs) have the ability to undergo osteogenic, adipogenic and chondrogenic differentiation. Cytochemical staining and gene expression analysis show that ASCs have a greater capacity for adipogenic differentiation compared to BM-MSCs and fibroblasts. Different methods of inducing adipogenesis also affect the extent and profile of adipogenic differentiation in MSCs. Goat fibroblasts were not capable of osteogenesis, hence distinguishing them from the MSCs. Goat MSCs and fibroblasts express CD90, CD105, CD73 but not CD45, and exhibit cytoplasmic localization of OCT4 protein. Goat MSCs can be stably transfected by Nucleofection, but, as evidenced by colony-forming efficiency(CFE), yield significantly different levels of progenitor cells that are robust enough to proliferate into colonies of integrants following G418 selection.BM-MSCs expanded over increasing passages in vitro maintained karyotypic stability up to 20 passages in culture,exhibited an increase in adipogenic differentiation and CFE, but showed altered morphology and amenability to genetic modification by selection.Conclusions: Our findings provide characterization information on goat MSCs, and show that there can be significant differences between MSCs isolated from different tissues and from within the same tissue. Fibroblasts do not exhibit trilineage differentiation potential at the same capacity as MSCs, making it a more reliable method for distinguishing MSCs from fibroblasts, compared to cell surface marker expression.     

Spontaneous differentiation of adult rat marrow stromal cells in a long-term culture

It is well recognized that bone marrow stromal cells (MSCs) can differentiate into neuron-like cells when supplemented with growth factors and/or chemical treatments. We demonstrated that primary MSCs obtained from adult rats could spontaneously differentiate into neural precursor cells after long-term culture. During the outset of in vitro culture, less than 0.1% of adult rat primary MSCs expressed nestin, the common protein of neural precursors. These MSCs didn't show neuronal morphology nor express neuronal antigens. In contrast, after continuous maintenance for 6 weeks, a significant subpopulation of MSCs formed cellular clumps and expressed nestin (32.3 +/- 6.3%). Less than 0.1% of cells expressing immature neuron marker betaIII-tubulin could be detected in these prolonged cultured MSCs. After serum deprivation and growth factor supplement, these nestin-positive cells could express neuron-like morphology and neuron-specific markers NF-H, betaIII-tubulin, tau, and neurotransmitter GABA. In contrast, the MSCs without prolonged culture didn't show neuronal morphology nor neuronal markers even after serum withdrawal and growth factors stimulation. These results demonstrated that neural precursors could be obtained from long-term cultured MSCs, and suggested that MSCs should be useful as a potential source for treatment of neurological disease.     

体外诱导牛骨髓间充质干细胞向乳腺样上皮细胞分化的初步研究

为培育转基因肉牛提供种子细胞及进一步丰富牛骨髓间充质干细胞(bone marrow mesenchymal stem cells,BMSC)的多向分化潜能,本试验利用细胞免疫荧光染色方法和分子生物学方法初步探讨在表皮生长因子、胰岛素、催产素和孕酮等条件下,体外诱导牛BMSC向乳腺样上皮细胞分化的可能性。利用不同浓度的诱导液对纯化稳定的P4、P8和P12代牛BMSC进行体外诱导,并对诱导后的细胞进行细胞免疫荧光观察和RT-PCR鉴定。结果显示,诱导后部分BMSC细胞呈多角形,而不再呈明显的梭形和纺锤形,经细胞角蛋白18免疫荧光染色后出现明显的荧光。P4代牛BMSC在诱导液Ⅱ的诱导作用下分化效果显著。RT-PCR结果显示,诱导分化后细胞角蛋白19基因、β-酪蛋白基因及αs1-酪蛋白基因在细胞中表达。因此,在体外,多因子联合诱导可使牛BMSC初步分化为乳腺样上皮细胞并且在诱导液Ⅱ的联合诱导下分化作用最明显。     

Differential patterns of nestin and glial fibrillary acidic protein expression in mouse hippocampus during postnatal development

Intermediate filaments, including nestin and glial fibrillary acidic protein (GFAP), are important for the brain to accommodate neural activities and changes during development. The present study examined the temporal changes of nestin and GFAP protein levels in the postnatal development of the mouse hippocampus. Mouse hippocampi were sampled on postnatal day (PND) 1, 3, 6, 18, and 48. Western blot analysis showed that nestin expression was high at PND 1 and markedly decreased until PND 18. Conversely, GFAP expression was acutely increased in the early phase of postnatal development. Nestin immunoreactivity was localized mainly in the processes of ramified cells at PND 1, but expression subsequently decreased. In contrast, GFAP was evident mainly in the marginal cells of the hippocampus at PND 1, but immunoreactivity revealed satellite, radial, or ramified shapes of the cells from PND 6-48. This study demonstrates that the opposing pattern of nestin and GFAP expressions in mouse hippocampus during postnatal development occur in the early development stage (PND 1-18), suggesting that the opposing change of nestin and GFAP in early postnatal development is important for neural differentiation and positioning in the mouse hippocampus.     

Bone Marrow Mesenchymal Stem Cells: From Characterization of Neural Differentiation to a Possible Therapeutic Use in Neurodegeneration

Bone marrow derived stromal cells are of mesenchymal origin and precursor cells for skeletal tissue components such as chondroblasts and osteoblasts. Furthermore, under experimental conditions, a differentiation potency into myogenic and neuronal cells could be demonstrated. Because of their multipotency these cells represent a population of non-haematogen stem cells that can be regarded as an alternative to human embryonic stem cells for future autologous cell replacement therapies. For a closer look at the differentiation capacity of these cells, rat and human bone marrow stromal cells were isolated from the femur bone and kept in the cell culture applying different cultivation protocols. In a cultivation medium with a serum content of 20%, the majority of these cells express a variety of neuronal markers such as ß-III Tubulin and NeuN as well as the astrocyte marker GFAP, while a minority of about 20% express the marker for neural precursor cells nestin. Cultivation in a chemically defined serum free medium results in the differentiation of a markedly higher percentage of nestin positive neural precursor-like cells. Using bFGF in combination with B27 these cells can be forced to form three dimensionally organized spheres. In order to elucidate a possible therapeutical potency of the bone marrow derived cells the synthesis of neurotrophic factors such as BDNF and NGF were analysed using the ELISA technique. Furthermore, they can be infected using a third generation adenoviral vector with high efficiency and show migratory activity in vitro . After injection of bone marrow derived mesenchymal stem cells into the lateral ventricle of adult rats they adhere to the ependymocytes and pass the ependymal barrier in order to settle in the subventricular space.     

崂山奶山羊胎儿骨髓间充质干细胞（BMSCs）的分离培养及成神经诱导分化

旨在建立崂山奶山羊胎儿骨髓间充质干细胞（BMSCs）体外分离培养方法,并研究其生物学特性和成神经分化的能力。取怀孕3个月的崂山奶山羊胎儿股骨,分离培养骨髓间充质干细胞,并进行传代培养,测定其细胞倍增时间,利用RT-PCR技术检测Oct4、Nanog、Sox2基因的表达;取P3 BMSCs分别向成神经细胞进行诱导分化,并从组织学水平和基因水平进行鉴定。结果表明,分离得到的胎儿骨髓间充质干细胞大小较为均匀,呈梭形的成纤维细胞样,可表达Oct4、Nanog、Sox2基因;传代接种后第4天进入指数生长期,第8天进入平台期,前10代BMSCs的平均倍增时间为29.7 h;P3 BMSCs成神经诱导后,尼氏体经甲苯胺蓝染色后可见紫蓝色,其特异性表达基因ENO2和GFAP表达呈阳性。获得的崂山奶山羊BMSCs具有成神经分化潜能。     

New Insights into the Neural Differentiation Potential of Canine Adipose Tissue‐Derived Mesenchymal Stem Cells

Adipose tissue‐derived stem cells (ASCs) can be obtained from different adipose tissue sources within the body. It is an abundant cell pool, easily accessible, suitable for cultivation and expansion in vitro and preparation for therapeutic approaches. Amongst these therapeutic approaches are tissue engineering and nervous system disorders such as spinal cord injuries. For such treatment, ASCs have to be reliably differentiated in to the neuronal direction. Therefore, we investigated the neural differentiation potential of ASCs using protocols with neurogenic inductors such as valproic acid and forskolin, while dog brain tissue served as control. Morphological changes could already be noticed 1 h after neuronal induction. Gene expression analysis revealed that the neuronal markers nestin and βIII‐tubulin as well as MAP2 were expressed after induction of neuronal differentiation. Additionally, the expression of the neurotrophic factors NGF, BDNF and GDNF was determined. Some of the neuronal markers and neurotrophic factors were already expressed in undifferentiated cells. Our findings point out that ASCs can reliably be differentiated into the neuronal lineage; therefore, these cells are a suitable cell source for cell transplantation in disorders of the central nervous system. Follow‐up studies would show the clinical benefit of these cells after transplantation.     

Generation of neuronal-like cells from umbilical cord blood-derived mesenchymal stem cells of a RFP-transgenic cloned cat

Umbilical cord blood (UCB)-derived mesenchymal stem cells (MSCs) are multipotent adult stem cells, which can differentiation into cells of connective tissue and neural lineages. This study investigated the potential for neuronal differentiation of red fluorescent protein (RFP)-transgenic cat UCB-derived MSCs. The cells were cultured in pre-induction medium for 24 hr and in neuronal-induction medium for 72 hr. Immunofluorescent staining showed that 6.85% of the total cells were beta III-tubulin-positive, 3.37% were neurofilament light (NF-L)-positive and 7.04% were neurofilament medium (NF-M)-positive. A beta III-tubulin band was detected by western blot analysis. Our results demonstrate that RFP-transgenic UCB-derived MSCs can be differentiated into neuronal cells in vitro. Thus, RFP-transgenic MSCs could provide alternative tracing material for stem cell transplantation.     

Characterization of neuron-like cells derived from canine bone marrow stromal cells

Regenerative therapy using bone marrow stromal cells (BMSCs) has begun to be clinically applied in humans and dogs for neurological disorders such as spinal cord injury. Under appropriate conditions in vitro, BMSCs differentiate into neuronal cells, which may improve the effects of regenerative therapy. In this study, we evaluated canine neuron-like cells (NLCs) derived from BMSCs. We speculated on their suitability for neuro-transplantation from the point of view of their morphological features, long-term viability, abundant availability, and ability to be subcultured. Canine NLCs were differentiated as follows: third-passage BMSCs were maintained in pre-induction medium containing 2-mercaptoethanol and dimethylsulfoxide for 5 h, and then cells were transferred to neuronal induction medium containing fetal bovine serum, basic fibroblast growth factor, epidermal growth factor, dibutyryl cyclic AMP, and isobutylmethylxanthine for 7 or 14 days. Canine NLCs fulfilled the transplantation criteria and expressed markers of both immature neurons (nestin, 84.7 %) and mature neuronal cells (microtubule-associated protein-2, 95.7 %; βIII-tubulin protein, 12.9 %; glial fibrillary acidic protein, 9.2 %). These results suggest that canine BMSCs can be induced to differentiate into neuronal cells and may be suitable for neuro-transplantation. This study may provide information for improving cellular therapy for neurological diseases.     

Impact of source tissue and ex vivo expansion on the characterization of goat mesenchymal stem cells

Background

There is considerable interest in using goats as models for genetically engineering dairy animals and also for using stem cells as therapeutics for bone and cartilage repair. Mesenchymal stem cells (MSCs) have been isolated and characterized from various species, but are poorly characterized in goats.

Results

Goat MSCs isolated from bone marrow (BM-MSCs) and adipose tissue (ASCs) have the ability to undergo osteogenic, adipogenic and chondrogenic differentiation. Cytochemical staining and gene expression analysis show that ASCs have a greater capacity for adipogenic differentiation compared to BM-MSCs and fibroblasts. Different methods of inducing adipogenesis also affect the extent and profile of adipogenic differentiation in MSCs. Goat fibroblasts were not capable of osteogenesis, hence distinguishing them from the MSCs. Goat MSCs and fibroblasts express CD90, CD105, CD73 but not CD45, and exhibit cytoplasmic localization of OCT4 protein. Goat MSCs can be stably transfected by Nucleofection, but, as evidenced by colony-forming efficiency (CFE), yield significantly different levels of progenitor cells that are robust enough to proliferate into colonies of integrants following G418 selection. BM-MSCs expanded over increasing passages in vitro maintained karyotypic stability up to 20 passages in culture, exhibited an increase in adipogenic differentiation and CFE, but showed altered morphology and amenability to genetic modification by selection.

Conclusions

Our findings provide characterization information on goat MSCs, and show that there can be significant differences between MSCs isolated from different tissues and from within the same tissue. Fibroblasts do not exhibit trilineage differentiation potential at the same capacity as MSCs, making it a more reliable method for distinguishing MSCs from fibroblasts, compared to cell surface marker expression.

Electronic supplementary material

The online version of this article (doi:10.1186/2049-1891-6-1) contains supplementary material, which is available to authorized users.     

Isolation,Culture and Multiple Differentiation Induction of Nanyang Bovine Bone Marrow Mesenchymal Stem Cells

The study aimed to build the method of Nanyang bovine bone marrow-derived mesenchymal stem cells (BMSCs) separation culture in vitro, and study its bionomics and the ability of multiple differentiation induction on this basis. Using bone marrow puncture to take rib bone marrow of 3 months calf, isolation and culture BMSCs, subcultured and determined its curve of growth, detected Oct4, Nanog, Sox2 genes expression by RT-PCR technique, then took P3 BMSCs into neural and fat cells to carry out induction differentiation, and took the use of histology staining technique and RT-PCR technique to detect. The results of the BMSCs were uniform sindleshaped in appearance; RT-PCR could dectect the expression of stem cell factor Oct4, Nanog, Sox2. The results showed that an "S" shape growth curve of cell at different generations times, it entered exponential growth stage at the 3rd day generally, and entered plateau after then the 7th day. Into nerve after induction, stained with toluidine blue was apparent throughout the structure of Nissl substance, ENO2 and GFAP genes showed a positive expression. After adipogenic differentiation of ASCs was assessed by oil Red O staining which showed a large number of lipiddroplet, RT-PCR dectected Leptin and PPAR genes showing a positive expression. The tests showed that had successfully isolated from Nanyang bovine BMSCs and it had the potential of multidirectional differentiation.     

南阳牛骨髓间充质干细胞的分离培养及多向分化

本研究旨在建立南阳牛骨髓间充质干细胞(bone marrow-derived mesenchymal stem cells,BMSCs)体外分离培养方法,在此基础上研究其生物学特性和多向分化的能力。采用骨髓穿刺法取3月龄小牛的肋骨骨髓,分离培养BMSCs,传代培养并测定其生长曲线,RT-PCR检测Oct4、Nanog、Sox2基因的表达,然后取P3 BMSCs分别向神经和脂肪细胞进行诱导分化,并利用组织学染色技术和RT-PCR技术进行鉴定。结果表明,分离得到的BMSCs大小均匀,多呈梭形的成纤维细胞样生长;RT-PCR可检测到干细胞因子Oct4、Nanog、Sox2的表达;不同代次细胞生长曲线呈S型,一般在第3天时进入指数生长期,第7天后进入平台期;成神经诱导后,甲苯胺蓝染色可见明显的尼氏体结构,RT-PCR检测ENO2和GFAP基因表达呈阳性;成脂肪诱导后,油红O染色后可见大量的脂滴存在,RT-PCR检测Leptin和PPAR基因表达呈阳性。试验证明,成功分离得到了南阳牛BMSCs,且其具有多向诱导分化潜能。     

Expression of neural markers on bone marrow-derived canine mesenchymal stem cells

OBJECTIVE: To evaluate cell surface markers of bone marrow-derived canine mesenchymal stem cells (MSCs) by use of flow cytometric analysis and determine whether canine MSCs express proteins specific to neuronal and glial cells. SAMPLE POPULATION: Bone marrow aspirates collected from iliac crests of 5 cadavers of young adult dogs. PROCEDURES: Flow cytometric analysis was performed to evaluate cell surface markers and homogeneity of third-passage MSCs. Neural differentiation of canine MSCs was induced by use of dibutyryl cAMP and methyl-isobutylxanthine. Expressions of neuronal (beta III-tubulin) and glial (glial fibrillary acidic protein [GFAP] and myelin basic protein) proteins were evaluated by use of immunocytochemical and western blot analyses before and after neural differentiation. RESULTS: Third-passage canine MSCs appeared morphologically homogeneous and shared phenotypic characteristics with human and rodent MSCs. Immunocytochemical and western blot analyses revealed that canine MSCs constitutively expressed beta III-tubulin and GFAP. After induction of neural differentiation, increased expression of GFAP was found in all samples, whereas such change was inconsistent in beta III-tubulin expression. Myelin basic protein remained undetectable on canine MSCs for these culture conditions. CONCLUSIONS AND CLINICAL RELEVANCE: Canine bone marrow-derived mononuclear cells yielded an apparently homogeneous population of MSCs after expansion in culture. Expanded canine MSCs constitutively expressed neuron or astrocyte specific proteins. Furthermore, increases of intracellular cAMP concentrations induced increased expression of GFAP on canine MSCs, which suggests that these cells may have the capacity to respond to external signals. Canine MSCs may hold therapeutic potential for treatment of dogs with neurologic disorders.     

佐剂性关节炎大鼠成纤维样滑膜细胞的体外培养与鉴定

探讨佐剂性关节炎(AA)大鼠成纤维样滑膜细胞(FLS)的体外培养及鉴定方法,制备AA大鼠模型,采用组织块培养法培养AA大鼠FLS,并通过形态学、透射电镜及RT-PCR方法对FLS进行鉴定.结果表明,培养的滑膜细胞具有成纤维细胞的形态和特征,呈长梭形板向生长,RT-PCR方法检测波形蛋白表达较高.本研究成功地培养出了AA...     

Phenotype and function of murine peritoneal cavity macrophage derived-dendritic cells

The accessory activity was reported in murine peritoneal cavity macrophage derived dendritic cells (PEC-DC) in a mixed lymphocyte reaction (MLR). Here we continue the characterization of the generated PEC-DC using the criteria of morphology, phenotype and other accessory function. We have demonstrated that murine peritoneal cavity macrophages can be induced to differentiate in vitro into cells exhibiting typical dendritic cell (DC) morphology, phenotype and function. The proliferative capacity of the progenitors was amplified in the first step of the culture (day 0-7) using a combination of early cytokines: interleukin 4 and granulocyte-macrophage colony-stimulating factor. The second step of the culture started at day 7 with the removal of early growth factors to allow differentiation and final maturation of DC during 2 days of culture with interferon gamma plus either Toxoplasma lysate antigen (TLA) or lipopolysaccharide (LPS), a bacterial agent as a DC maturing agent. The resulting DC population exhibited typical DC morphology and expressed higher levels of MHC class II and the co-stimulatory molecules CD80 and CD86 compared to the untreated peritoneal cells. The generated DC cells efficiently presented soluble protein antigen to CD3(+) spleen T cells.     

Influence of an autologous serum-supplemented medium on the proliferation and differentiation into neurons of canine bone marrow stromal cells

We investigated the influence of autologous serum (AS)-supplemented medium on the proliferation and differentiation into neurons of canine bone marrow stromal cells (BMSCs). Canine BMSCs were cultured using α-MEM only, α-MEM with 10% fetal bovine serum (FBS), and 5, 10 and 20% AS-supplemented α-MEM. Growth of canine BMSCs was observed in all AS groups. The proliferation capacity of canine BMSCs in the AS groups was similar to that in the FBS group. No significant differences between the FBS and AS groups were observed in the percentage of the cells that changed to the neuron-like morphology and neuron-specific enolase-positive ratio after neuronal differentiation. Canine BMSCs cultured using AS-supplemented medium were able to proliferate and showed neuronal differentiation potency.     

Further insights into the characterization of equine adipose tissue-derived mesenchymal stem cells

Adipose tissue-derived stem cells (ADSCs) represent a promising subpopulation of adult stem cells for tissue engineering applications in veterinary medicine. In this study we focused on the morphological and molecular biological properties of the ADSCs. The expression of stem cell markers Oct4, Nanog and the surface markers CD90 and CD105 were detected using RT-PCR. ADSCs showed a proliferative potential and were capable of adipogenic and osteogenic differentiation. Expression of Alkaline phosphatase (AP), phosphoprotein (SPP1), Runx2 and osteocalcin (OC) mRNA were positive in osteogenic lineages and peroxisome proliferator activated receptor (Pparγ2) mRNA was positive in adipogenic lineages. ADSCs show stem cell and surface marker profiles and differentiation characteristics that are similar to but distinct from other adult stem cells, such as bone marrow-derived mesenchymal stem cells (BM-MSCs). The availability of an easily accessible and reproducible cell source may greatly facilitate the development of stem cell based tissue engineering and therapies for regenerative equine medicine.     

猪胎儿神经干细胞的分离培养和分化

本研究旨在从猪胎儿脑组织中分离培养神经干细胞,观察神经干细胞生长特性和体外增殖、分化特点.利用神经干细胞培养体系,从胎龄30 d的猪胎儿脑组织中分离培养神经干细胞并诱导神经干细胞贴壁分化,采用RT-PCR技术检测干细胞和分化细胞表面标志或相关基因.结果成功分离培养出神经干细胞,神经干细胞具有分化潜能.神经干细胞中Nestin表达强阳性,β-actin、DCX、Hesl、Oct4、Desmin、CD-90、Nanog和Sox2表达阳性;体外诱导的神经干细胞可以分化为星形胶质细胞(表达GFAP)、少突胶质细胞(表达GalC)和神经元细胞(表达NF、NSE和MAP2).结果提示,从猪胎儿脑组织分离神经干细胞具有可行性和有效性,神经干细胞具有自我更新、增殖和分化潜能.     

西门塔尔牛表皮干细胞的分离培养与生物学特性研究

旨在建立西门塔尔牛表皮干细胞(epidermal stem cell, EpSCs)分离培养体系,探究其生物学特性,为西门塔尔牛种质资源保存提供新方法,为干细胞治疗研究提供种子细胞。采用3～4月龄西门塔尔牛背部表皮,通过酶消化法和组织贴壁法两种方法分离培养西门塔尔牛EpSCs,绘制EpSCs生长曲线探讨其增殖能力。通过免疫荧光鉴定EpSCs表面标记物(ITG β1、P63和CD71),通过RT-PCR分析EpSCs特异性基因(ITG β1、KRT19和ITG α6)表达情况。通过体外诱导EpSCs分化为脂肪细胞、成骨细胞和软骨细胞检测其分化潜能。结果显示,组织块贴壁法获得的EpSCs纯度较低,酶消法获得的EpSCs纯度较高,细胞传代至P28代时开始逐渐老化。EpSCs细胞生长曲线呈“S”型。免疫荧光结果显示EpSCs表面特异性标记物ITG β1、P63和CD71呈阳性表达,RT-PCR结果显示EpSCs高度表达ITG β1、KRT19和ITG α6,不表达CD31基因。EpSCs诱导分化脂肪细胞时,产生可被油红O着色的脂滴,经鉴定细胞阳性表达脂肪细胞PPAR-γ和LPL特异性基因。Ep...