Mesenchymal progenitor cells derived from traumatized human muscle

Mesenchymal stem cells (MSCs) derived from adult tissues are an important candidate cell type for cell‐based tissue engineering and regenerative medicine. Currently, clinical applications for MSCs require additional surgical procedures to harvest the autologous MSCs (i.e. from bone marrow) or commercial allogeneic alternatives. We have recently identified a population of mesenchymal progenitor cells (MPCs) in traumatized muscle tissue that has been surgically debrided from traumatic orthopaedic extremity wounds. The purpose of this study was to evaluate whether MPCs derived from traumatized muscle may provide a clinical alternative to bone‐marrow MSCs, by comparing their morphology, proliferation capacity, cell surface epitope profile and differentiation capacity. After digesting the muscle tissue with collagenase, the MPCs were enriched by a direct plating technique. The morphology and proliferation rate of the muscle‐derived MPCs was similar to bone‐marrow derived MSCs. Both populations expressed cell surface markers characteristic for MSCs (CD 73, CD 90 and CD105), and did not express markers typically absent on MSCs (CD14, CD34 and CD45). After 21 days in specific differentiation media, the histological staining and gene expression of the MPCs and MSCs was characteristic for differentiation into osteoblasts, chondrocytes and adipocytes, but not into myoblasts. Our findings demonstrate that traumatized muscle‐derived MPCs exhibit a similar phenotype and resemble MSCs derived from the bone marrow. MPCs harvested from traumatized muscle tissue may be considered for applications in tissue engineering and regenerative medicine following orthopaedic trauma requiring circumferential debridement. Copyright © 2009 John Wiley & Sons, Ltd.     

Traumatized muscle‐derived multipotent progenitor cells recruit endothelial cells through vascular endothelial growth factor‐A action

Traumatized muscle, such as that debrided from blast injury sites, is considered a promising and convenient tissue source for multipotent progenitor cells (MPCs), a population of adult mesenchymal stem cell (MSC)‐like cells. The present study aimed to assess the regenerative therapeutic potential of human traumatized muscle‐derived MPCs, e.g., for injury repair in the blast‐traumatized extremity, by comparing their pro‐angiogenic potential in vitro and capillary recruitment activity in vivo to those of MSCs isolated from human bone marrow, a widely‐used tissue source. MPCs were tested for their direct and indirect effects on human microvascular endothelial cells (ECs) in vitro. The findings reported here showed that MPC‐conditioned culture medium (MPC‐CM), like MSC‐CM, promoted EC‐cord network branching. Silent (si)RNA‐mediated silencing of vascular endothelial growth factor‐A (VEGF‐A) expression in MPCs attenuated this effect. In a chick embryonic chorioallantoic membrane in vivo angiogenesis assay, MPCs encapsulated in photocrosslinked gelatin scaffold recruited blood vessels more efficiently than either MSCs or human foreskin fibroblasts. Together, these findings support the potential application of traumatized muscle‐derived MPCs in cell‐based regenerative medicine therapies as a result of their influence on EC organization. Copyright © 2017 John Wiley & Sons, Ltd.     

GDNF 基因诱导大鼠骨髓间充质干细胞促周围神经再生的实验研究

目的：探讨胶质细胞源性神经营养因子（GDNF）诱导骨髓间充质干细胞（BMSCs）促周围神经再生。方法建立大鼠坐骨神经损伤模型,实验分为2组：对照组为未经诱导 BMSCs 组,实验组为 GDNF 基因诱导后 BMSCs组。每组20只 SD 大鼠。①术后4周和8周观察坐骨神经指数和腓肠肌湿质量恢复率。②术后8周测量再生神经纤维轴突直径、髓鞘厚度及有髓神经纤维计数。③术后4周腓肠肌肌细胞行 DAPI 染色。④术后8周坐骨神经扫面电镜观察神经丝再生交联情况。结果经 GDNF 基因诱导 BMSCs 组各方面检测指标均较对照组为好,其中诱导后实验组扫描电镜下观察周围神经再生更加明显。结论GDNF 基因诱导的间充质干细胞对周围神经再生有着显著的疗效。     

Effect of platelet‐rich plasma (PRP) concentration on proliferation,neurotrophic function and migration of Schwann cells in vitro

Platelet‐rich plasma (PRP) contains various growth factors and appears to have the potential to promote peripheral nerve regeneration, but evidence is lacking regarding its biological effect on Schwann cells (SCs). The present study was designed to investigate the effect of PRP concentration on SCs in order to determine the plausibility of using this plasma‐derived therapy for peripheral nerve injury. PRP was obtained from rats by double‐step centrifugation and was characterized by determining platelet numbers and growth factor concentrations. Primary cultures of rat SCs were exposed to various concentrations of PRP (40%, 20%, 10%, 5% and 2.5%). Cell proliferation assays and flow cytometry were performed to study to assess SC proliferation. Quantitative real‐time PCR and ELISA analysis were performed to determine the ability of PRP to induce SCs to produce nerve growth factor (NGF) and glial cell line‐derived neurotrophic factor (GDNF). Microchemotaxis assay was used to analyse the cell migration capacity. The results obtained indicated that the platelet concentration and growth factors in our PRP preparations were significantly higher than in whole blood. Cell culture experiments showed that 2.5–20% PRP significantly stimulated SC proliferation and migration compared to untreated controls in a dose‐dependent manner. In addition, the expression and secretion of NGF and GDNF were significantly increased. However, the above effects of SCs were suppressed by high PRP concentrations (40%). In conclusion, the appropriate concentration of PRP had the potency to stimulate cell proliferation, induced the synthesis of neurotrophic factors and significantly increased migration of SCs dose‐dependently. Copyright © 2013 John Wiley & Sons, Ltd.     

Functional collagen conduits combined with human mesenchymal stem cells promote regeneration after sciatic nerve transection in dogs

Numerous studies have focused on the development of novel and innovative approaches for the treatment of peripheral nerve injury using artificial nerve guide conduits. In this study, we attempted to bridge 3.5‐cm defects of the sciatic nerve with a longitudinally oriented collagen conduit (LOCC) loaded with human umbilical cord mesenchymal stem cells (hUC‐MSCs). The LOCC contains a bundle of longitudinally aligned collagenous fibres enclosed in a hollow collagen tube. Our previous studies showed that an LOCC combined with neurotrophic factors enhances peripheral nerve regeneration. However, it remained unknown whether an LOCC seeded with hUC‐MSCs could also promote regeneration. In this study, using various histological and electrophysiological analyses, we found that an LOCC provides mechanical support to newly growing nerves and functions as a structural scaffold for cells, thereby stimulating sciatic nerve regeneration. The LOCC and hUC‐MSCs synergistically promoted regeneration and improved the functional recovery in a dog model of sciatic nerve injury. Therefore, the combined use of an LOCC and hUC‐MSCs might have therapeutic potential for the treatment of peripheral nerve injury.     

Glial cell‐derived neurotrophic factor promotes dental pulp stem cell migration

Preserving the vitality of the teeth is critical in maintaining the function and aesthetics of teeth during dental treatment. Dental pulp stem cells (DPSCs) are mesenchymal cells that are demonstrated to possess stem cell properties, such as self‐renewal, proliferation, and pluripotency. DPSCs can be obtained through non‐invasive procedure from the dental pulp and become potential resources for tissue regeneration. Neurotrophic factors are known to promote survival and growth of neurons. In the present study, we examined the expression of the glial cell‐derived neurotrophic factor (GDNF) family ligands and receptors and characterized the intracellular localization of them in DPSCs. GDNF increased the migration of the DPSCs. In addition, we found that the AKT and MAPK pathways were downstream of GDNF in regulating the DPSC wound healing and migration. Our results indicate that neurotrophic factors play a role in dental pulp regeneration and may be potential novel therapies for post pulpotomy treatment in adult teeth.     

Cultured cell‐derived extracellular matrices to enhance the osteogenic differentiation and angiogenic properties of human mesenchymal stem/stromal cells

Cell‐derived extracellular matrix (ECM) consists of a complex assembly of fibrillary proteins, matrix macromolecules, and associated growth factors that mimic the composition and organization of native ECM micro‐environment. Therefore, cultured cell‐derived ECM has been used as a scaffold for tissue engineering settings to create a biomimetic micro‐environment, providing physical, chemical, and mechanical cues to cells, and support cell adhesion, proliferation, migration, and differentiation. Here, we present a new strategy to produce different combinations of decellularized cultured cell‐derived ECM (dECM) obtained from different cultured cell types, namely, mesenchymal stem/stromal cells (MSCs) and human umbilical vein endothelial cells (HUVECs), as well as the coculture of MSC:HUVEC and investigate the effects of its various compositions on cell metabolic activity, osteogenic differentiation, and angiogenic properties of human bone marrow (BM)‐derived MSCs, vital features for adult bone tissue regeneration and repair. Our findings demonstrate that dECM presented higher cell metabolic activity compared with tissue culture polystyrene. More importantly, we show that MSC:HUVEC ECM enhanced the osteogenic and angiogenic potential of BM MSCs, as assessed by in vitro assays. Interestingly, MSC:HUVEC (1:3) ECM demonstrated the best angiogenic response of MSCs in the conditions tested. To the best of our knowledge, this is the first study that demonstrates that dECM derived from a coculture of MSC:HUVEC impacts the osteogenic and angiogenic capabilities of BM MSCs, suggesting the potential use of MSC:HUVEC ECM as a therapeutic product to improve clinical outcomes in bone regeneration.     

Delivery of chondroitinase ABC and glial cell line‐derived neurotrophic factor from silk fibroin conduits enhances peripheral nerve regeneration

Nerve conduits are a proven strategy for guiding axon regrowth following injury. This study compares degradable silk–trehalose films containing chondroitinase ABC (ChABC) and/or glial cell line‐derived neurotrophic factor (GDNF) loaded within a silk fibroin‐based nerve conduit in a rat sciatic nerve defect model. Four groups of silk conduits were prepared, with the following silk–trehalose films inserted into the conduit: (a) empty; (b) 1 µg GDNF; (3) 2 U ChABC; and (4) 1 µg GDNF/2 U ChABC. Drug release studies demonstrated 20% recovery of GDNF and ChABC at 6 weeks and 24 h, respectively. Six conduits of each type were implanted into 15 mm sciatic nerve defects in Lewis rats; conduits were explanted for histological analysis at 6 weeks. Tissues stained with Schwann cell S‐100 antibody demonstrated an increased density of cells in both GDNF‐ and ChABC‐treated groups compared to empty control conduits (p < 0.05). Conduits loaded with GDNF and ChABC also demonstrated higher levels of neuron‐specific PGP 9.5 protein when compared to controls (p < 0.05). In this study we demonstrated a method to enhance Schwann cell migration and proliferation and also foster axonal regeneration when repairing peripheral nerve gap defects. Silk fibroin‐based nerve conduits possess favourable mechanical and degradative properties and are further enhanced when loaded with ChABC and GDNF. Copyright © 2014 John Wiley & Sons, Ltd.     

骨髓间充质细胞构建组织工程神经修复坐骨神经缺损

背景:许旺细胞是周围神经组织工程的种子细胞,但体外分离、培养、纯化许旺细胞较困难.脱细胞同种异体神经移植物具有较强的修复外周神经缺损的能力,且可诱导骨髓间充质细胞分化为类许旺细胞,理论上骨髓间充质细胞可替代许旺细胞作为种子细胞应用于周围神经组织工程.目的:观察骨髓间充质细胞构建组织工程神经修复坐骨神经缺损的效果,评估骨髓间充质细胞作为种子细胞修复周围神经缺损的可行性.设计、时间及地点:随机对照动物实验,于2008-07/12在大理学院基础医学院实验室完成.材料:将30只SD大鼠按随机数字表法分为3组,每组10只.骨髓间充质细胞+异体移植组将骨髓间充质细胞复合脱细胞同种异体神经移植物培养的组织工程神经与两断端用10/0无创线端端吻合;异体移植组将脱细胞同种异体神经移植物桥接;自体移植组将切断的坐骨神经旋转180°端端吻合.方法:运用骨髓间充质细胞构建的组织工程神经修复大鼠10 mm坐骨神经缺损,移植后12周通过坐骨神经功能指数、腓肠肌湿质量恢复率、S-100免疫组织化学染色、电镜等方法观察移植物修复效果.主要观察指标:复合物培养时观察细胞形态的变化;移植后观察坐骨神经功能指数及腓肠肌湿质量恢复率;通过甲苯胺蓝染色观察新生髓鞘形成和轴突生长及神经纤维的分布情况,结合透射电镜及S-100蛋白免疫组织化学染色,观察许旺细胞生长和神经纤维再生情况.结果:坐骨神经功能指数及腓肠肌湿质量恢复率的检测结果显示骨髓间充质细胞+异体移植组优于异体移植组(P<0.05).骨髓间充质细胞+异体移植组复合物中S-100的表达明显高于异体移植组,有髓神经纤维数量、有髓纤维直径和髓鞘厚度均大于异体移植组(P< 0.05),修复效果接近自体移植组.结论:骨髓间充质细胞构建的组织工程神经修复周围神经缺损的效果优于单纯的脱细胞同种异体神经移植物,骨髓间充质细胞作为种子细胞在周围神经组织工程中具有较强的应用价值.     

Angiogenic potential of human mesenchymal stromal cell and circulating mononuclear cell cocultures is reflected in the expression profiles of proangiogenic factors leading to endothelial cell and pericyte differentiation

Endothelial progenitors found among the peripheral blood (PB) mononuclear cells (MNCs) are interesting cells for their angiogenic properties. Mesenchymal stromal cells (MSCs) in turn can produce proangiogenic factors as well as differentiate into mural pericytes, making MSCs and MNCs an attractive coculture setup for regenerative medicine. In this study, human bone marrow‐derived MSCs and PB‐derived MNCs were cocultured in basal or osteoblastic medium without exogenously supplied growth factors to demonstrate endothelial cell, pericyte and osteoblastic differentiation. The expression levels of various proangiogenic factors, as well as endothelial cell, pericyte and osteoblast markers in cocultures were determined by quantitative polymerase chain reaction. Immunocytochemistry for vascular endothelial growth factor receptor‐1 and α‐smooth muscle actin as well as staining for alkaline phosphatase were performed after 10 and 14 days. Messenger ribonucleic acid expression of endothelial cell markers was highly upregulated in both basal and osteoblastic conditions after 5 days of coculture, indicating an endothelial cell differentiation, which was supported by immunocytochemistry for vascular endothelial growth factor receptor‐1. Stromal derived factor‐1 and vascular endothelial growth factor were highly expressed in MSC‐MNC coculture in basal medium but not in osteoblastic medium. On the contrary, the expression levels of bone morphogenetic protein‐2 and angiopoietin‐1 were significantly higher in osteoblastic medium. Pericyte markers were highly expressed in both cocultures after 5 days. In conclusion, it was demonstrated endothelial cell and pericyte differentiation in MSC‐MNC cocultures both in basal and osteoblastic medium indicating a potential for neovascularization for tissue engineering applications.     

Poly‐3‐hydroxybutyrate strips seeded with regenerative cells are effective promoters of peripheral nerve repair

Peripheral nerve injuries are often associated with loss of nerve tissue and require a graft to bridge the gap. Autologous nerve grafts are still the 'gold standard' in reconstructive surgery but have several disadvantages, such as sacrifice of a functional nerve, neuroma formation and loss of sensation at the donor site. Bioengineered grafts represent a promising approach to address this problem. In this study, poly‐3‐hydroxybutyrate (PHB) strips were used to bridge a 10 mm rat sciatic nerve gap and their effects on long‐term (12 weeks) nerve regeneration were compared. PHB strips were seeded with different cell types, either primary Schwann cells (SCs) or SC‐like differentiated adipose‐derived stem cells (dASCs) suspended in a fibrin glue matrix. The control group was PHB and fibrin matrix without cells. Functional and morphological properties of the regenerated nerve were assessed using walking track analysis, EMGs, muscle weight ratios and muscle and nerve histology. The animals treated with PHB strips seeded with SCs or dASCs showed significantly better functional ability than the control group. This correlated with less muscle atrophy and greater axon myelination in the cell groups. These findings suggest that the PHB strip seeded with cells provides a beneficial environment for nerve regeneration. Furthermore, dASCs, which are abundant and easily accessible, constitute an attractive cell source for future applications of cell therapy for the clinical repair of traumatic nerve injuries. Copyright © 2015 John Wiley & Sons, Ltd.     

联合应用NGF、CNTF和GDNF对大鼠坐骨神经结构和功能恢复的影响

目的：探讨联合应用NGF、CNTF和GDNF对大鼠坐骨神经结构和功能恢复的影响。方法：采用大鼠坐骨神经离断模型，实验动物按NGF、CNTF、GDNF单独使用，两两组合使用，三种因子同时应用以及对照组共分为8组。测量各组坐骨神经功能指数、神经电生理参数、腓肠肌湿重恢复率、再生神经纤维形态参数。结果：三种因子联合治疗组坐骨神经功能指数、神经传导速度、动作电位波幅、腓肠肌湿重恢复最佳；除髓鞘厚度略小于NGF和CNTF联合治疗组外．神经纤维直径、再生轴突数量及神经组织面积均大于其他各组。结论：联合应用NGF、CNTF和GDNF对再生神经结构和功能恢复的作用优于其中一种因子单独使用或两种因子联合应用。     

Conditioned media derived from mesenchymal stem cell cultures: The next generation for regenerative medicine

Recent studies suggest that the main driving force behind the therapeutic activity observed in mesenchymal stem cells (MSCs) are the paracrine factors secreted by these cells. These biomolecules also trigger antiapoptotic events to prevent further degeneration of the diseased organ through paracrine signalling mechanisms. In comparison with the normal physiological conditions, an increased paracrine gradient is observed within the peripheral system of diseased organs that enhances the migration of tissue‐specific MSCs towards the site of infection or injury to promote healing. Thus, upon administration of conditioned media derived from mesenchymal stem cell cultures (MSC‐CM) could contribute in maintaining the increased paracrine factor gradient between the diseased organ and the stem cell niche in order to speed up the process of recovery. Based on the principle of the paracrine signalling mechanism, MSC‐CM, also referred as the secretome of the MSCs, is a rich source of the paracrine factors and are being studied extensively for a wide range of regenerative therapies such as myocardial infarction, stroke, bone regeneration, hair growth, and wound healing. This article highlights the current technological applications and advances of MSC‐CM with the aim to appraise its future potential as a regenerative therapeutic agent.     

Mesenchymal stem cells from the Wharton's jelly of umbilical cord segments provide stromal support for the maintenance of cord blood hematopoietic stem cells during long-term ex vivo culture

BACKGROUND: Hematopoietic stem cells (HSCs) are routinely obtained from marrow, mobilized peripheral blood, and umbilical cord blood. Mesenchymal stem cells (MSCs) are traditionally isolated from marrow. Bone marrow–derived MSCs (BM‐MSCs) have previously demonstrated their ability to act as a feeder layer in support of ex vivo cord blood expansion. However, the use of BM‐MSCs to support the growth, differentiation, and engraftment of cord blood may not be ideal for transplant purposes. Therefore, the potential of MSCs from a novel source, the Wharton's jelly of umbilical cords, to act as stromal support for the long‐term culture of cord blood HSC was evaluated. STUDY DESIGN AND METHODS: Umbilical cord–derived MSCs (UC‐MSCs) were cultured from the Wharton's jelly of umbilical cord segments. The UC‐MSCs were then profiled for expression of 12 cell surface receptors and tested for their ability to support cord blood HSCs in a long‐term culture‐initiating cell (LTC‐IC) assay. RESULTS: Upon culture, UC‐MSCs express a defined set of cell surface markers (CD29, CD44, CD73, CD90, CD105, CD166, and HLA‐A) and lack other markers (CD45, CD34, CD38, CD117, and HLA‐DR) similar to BM‐MSCs. Like BM‐MSCs, UC‐MSCs effectively support the growth of CD34+ cord blood cells in LTC‐IC assays. CONCLUSION: These data suggest the potential therapeutic application of Wharton's jelly–derived UC‐MSCs to provide stromal support structure for the long‐term culture of cord blood HSCs as well as the possibility of cotransplantation of genetically identical, HLA‐matched, or unmatched cord blood HSCs and UC‐MSCs in the setting of HSC transplantation.     

自体肋间神经联合酸性成纤维细胞生长因子移植治疗高位脊髓损伤

背景:酸性成纤维细胞生长因子具有调节细胞增殖、移行、分化和生存的作用,也可以下调已知轴突再生的抑制因子如蛋白聚糖等,帮助轴突克服这些抑制因子,对神经纤维再生有重要作用.目的:观察酸性成纤维细胞生长因子联合周围神经移植治疗大鼠高位脊髓损伤的可行性及效果.方法:健康成年雌性SD大鼠108只随机抽签法分为自体神经组、自体神经联合生长因子组、高位脊髓横断组.咬除大鼠T_(8-10)棘突、椎板,显露硬膜囊,水平切断高位脊髓并切除3 mm,显微镜下确认无神经纤维相连.自体神经组、自体神经联合生长因子组取双侧第8～10对肋间神经各2 cm,将肋间神经交叉移植入高位脊髓缺损处(近端白质与远端灰质、远端白质与近端灰质),分别以纤维蛋白凝胶、含有酸性成纤维细胞生长因子的纤维蛋白凝胶固定植入的肋间神经,缝合硬膜.高位脊髓横断组断端间旷置.术后90 d,行体感诱发电位及运动诱发电位检测观察神经电生理恢复情况.术后76 d,生物素葡聚糖胺顺行神经示踪观察运动传导束恢复情况.术后60 d,后肢BBB运动功能评分观察肢体运动恢复情况.结果与结论:高位脊髓横断组大鼠均未引出体感及运动诱发电位波形.自体神经组、自体神经联合生长因子组均可引出体感及运动诱发电位,自体神经联合生长因子组体感诱发电位及运动诱发电位的平均潜伏期和波幅、BBB评分均明显优自体神经组(P＜0.01).自体神经组和自体神经联合生长因子组在损伤区有较多生物素葡聚糖胺标记阳性神经纤维通过,明显多于高位脊髓横断组(P＜0.01),自体神经联合生长因子组多于自体神.经组(P＜0.01).示自体周围神经移植酸性成纤维细胞生长因子能更好地恢复高位脊髓损伤后大鼠肢体运动功能.     

Cell–cell interaction between vocal fold fibroblasts and bone marrow mesenchymal stromal cells in three‐dimensional hyaluronan hydrogel

Mesenchymal stromal cells (MSCs) are multipotential adult cells present in all tissues. Paracrine effects and differentiating ability make MSCs an ideal cell source for tissue regeneration. However, little is known about how interactions between implanted MSCs and native cells influence cellular growth, proliferation, and behaviour. By using an in vitro three‐dimensional (3D) co‐culture assay of normal or scarred human vocal fold fibroblasts (VFFs) and bone marrow‐derived MSCs (BM‐MSCs) in a uniquely suited hyaluronan hydrogel (HyStem–VF), we investigated cell morphology, survival rate, proliferation and protein and gene expression of VFFs and BM‐MSCs. BM‐MSCs inhibited cell proliferation of both normal and scarred VFFs without changes in VFF morphology or viability. BM‐MSCs demonstrated decreased proliferation and survival rate after 7 days of co‐culture with VFFs. Interactions between BM‐MSCs and VFFs led to a significant increase in protein secretion of collagen I and hepatocyte growth factor (HGF) and a decrease of vascular endothelial growth factor (VEGF), monocyte chemotactic protein‐1 (MCP‐1) and interleukin‐6 (IL‐6). In particular, BM‐MSCs significantly upregulated matrix metalloproteinase 1 (MMP1) and HGF gene expression for scarred VFFs compared to normal VFFs, indicating the potential for increases in extracellular matrix remodelling and tissue regeneration. Application of BM‐MSCs‐hydrogels may play a significant role in tissue regeneration, providing a therapeutic approach for vocal fold scarring. Copyright © 2013 John Wiley & Sons, Ltd.     

Micropatterned three‐dimensional hydrogel system to study human endothelial–mesenchymal stem cell interactions

The creation of vascularized engineered tissues of clinically relevant size is a major challenge of tissue engineering. While it is known that endothelial and mural vascular cells are integral to the formation of stable blood vessels, the specific cell types and optimal conditions for engineered vascular networks are poorly understood. To this end, we investigated the vasculogenic potential of human mesenchymal stem cell (MSC) populations derived from three different sources: (a) bone marrow aspirates; (b) perivascular cells from the umbilical cord vein; and (c) perivascular cells from the umbilical cord artery. Cell populations were isolated and identified as MSCs according to their phenotypes and differentiation potential. Human umbilical vein endothelial cells (HUVECs) were used as a standard for endothelial cells. A novel co‐culture system was developed to study cell–cell interactions in a spatially controlled three‐dimensional (3D) fibrin hydrogel model. Using microfluidic patterning, it was possible to localize hydrogel‐encapsulated HUVECs and MSCs within separate channels spaced at 500, 1000 or 2000 µm. All three MSC populations had similar expression profiles of mesenchymal cell markers and similar capacity for osteogenic and adipogenic differentiation. However, bone marrow‐derived MSCs (but not umbilical vein or artery derived MSCs) showed strong distance‐dependent migration toward HUVECs and supported the formation of stable vascular networks resembling capillary‐like vasculature. The presented approach provides a simple and robust model to study the cell–cell communication of relevance to engineering vascularized tissues. Copyright © 2009 John Wiley & Sons, Ltd.     

心肌条件培养液与5-氮胞苷诱导骨髓基质干细胞向心肌样细胞的分化

背景:骨髓基质干细胞可以明显改善心肌缺血时的心脏功能,但其直接分化为心肌细胞并参与心功能恢复的机制尚不明确.目的:探讨心肌条件培养液与5-氮胞苷诱导骨髓基质干细胞分化为心肌样细胞的作用.方法:全骨髓贴壁法分离培养骨髓基质干细胞,将第6代骨髓基质干细胞随机分为4组:5-氮胞苷+心肌条件培养液联合诱导组;5-氮胞苷组;心肌条件培养液组;基础培养基组(空白组).用心肌条件培养液和5-氮胞苷诱导3周后用免疫组化法测定各组心肌肌钙蛋白表达,并采用单因素方差分析检验进行统计学分析.结果与结论:在体外心肌条件培养液可以诱导骨髓基质干细胞向心肌细胞分化,提示其中细胞因子可能起关键作用,但心肌条件培养液的这种作用要弱于化学诱导剂5-氮胞苷的诱导作用,且联合诱导作用更强.     

Decellularized nerve matrix hydrogel and glial‐derived neurotrophic factor modifications assisted nerve repair with decellularized nerve matrix scaffolds

Nerve defects are challenging to address clinically without satisfactory treatments. As a reliable alternative to autografts, decellularized nerve matrix scaffolds (DNM‐S) have been widely used in clinics for surgical nerve repair. However, DNM‐S remain inferior to autografts in their ability to support nerve regeneration for long nerve defects. In this study, we systematically and clearly presented the nano‐architecture of nerve‐specific structures, including the endoneurium, basement membrane and perineurium/epineurium in DNM‐S. Furthermore, we modified the DNM‐S by supplementing decellularized nerve matrix hydrogel (DNMG) and glial‐derived neurotrophic factor (GDNF) and then bridged a 50‐mm sciatic nerve defect in a beagle model. Fifteen beagles were randomly divided into three groups (five per group): an autograft group, DNM‐S group and GDNF‐DNMG‐modified DNM‐S (DNM‐S/GDNF@DNMG) group. DNM‐S/GDNF@DNMG, as optimized nerve grafts, were used to bridge nerve defects in the same manner as in the DNM‐S group. The repair outcome was evaluated by behavioural observations, electrophysiological assessments, regenerated nerve tissue histology and reinnervated target muscle examinations. Compared with the DNM‐S group, limb function, electrophysiological responses and histological findings were improved in the DNM‐S/GDNF@DNMG group 6 months after grafting, reflecting a narrower gap between the effects of DNM‐S and autografts. In conclusion, modification of DNM‐S with DNMG and GDNF enhanced nerve regeneration and functional recovery, indicating that noncellular modification of DNM‐S is a promising method for treating long nerve defects.     

周围神经再生及其影响因素

周围神经损伤的形态结构重建和功能恢复,是相当复杂的生物学问题之一,其影响因素众多。此文概述了周围神经损伤后的再生过程;着重综述了雪旺细胞、神经营养因子以及神经基质各种成分对周围神经再生和功能恢复的影响。