The potential of nestin-expressing hair follicle stem cells in regenerative medicine

The hair follicle bulge area is an abundant, easily accessible source of actively growing pluripotent adult stem cells. Nestin, a protein marker for neural stem cells, is also expressed in follicle stem cells and their immediate, differentiated progeny. Green fluorescent protein (GFP), whose expression is driven by the nestin regulatory element in transgenic mice, serves to mark hair follicle stem cells. The pluripotent nestin-driven GFP stem cells are positive for the stem cell marker CD34, but negative for keratinocyte marker keratin 15, suggesting their relatively undifferentiated state. These cells can differentiate into neurons, glia, keratinocytes, smooth muscle cells and melanocytes in vitro. In vivo studies show that nestin-driven GFP hair follicle stem cells can differentiate into blood vessels and neural tissue after transplantation to the subcutis of nude mice. Hair follicle stem cells implanted into the gap region of a severed sciatic or tibial nerve greatly enhance the rate of nerve regeneration and the restoration of nerve function. The follicle cells transdifferentiate largely into Schwann cells, which are known to support neuron regrowth. The transplanted mice regain the ability to walk normally. Thus, hair follicle stem cells provide an effective, accessible, autologous source of stem cells for treatment of peripheral nerve injury.     

Accelerated outgrowth in cross‐facial nerve grafts wrapped with adipose‐derived stem cell sheets

In this study, we devised a novel cross‐facial nerve grafting (CFNG) procedure using an autologous nerve graft wrapped in an adipose‐derived stem cell (ADSC) sheet that was formed on a temperature‐responsive dish and examined its therapeutic effect in a rat model of facial palsy. The rat model of facial paralysis was prepared by ligating and transecting the main trunk of the left facial nerve. The sciatic nerve was used for CFNG, connecting the marginal mandibular branch of the left facial nerve and the marginal mandibular branch of the right facial nerve. CFNG alone, CFNG coated with an ADSC suspension, and CFNG wrapped in an ADSC sheet were transplanted in eight rats each, designated the CFNG, suspension, and sheet group, respectively. Nerve regeneration was compared histologically and physiologically. The time to reinnervation, assessed by a facial palsy scoring system, was significantly shorter in the sheet group than in the other two groups. Evoked compound electromyography showed a significantly higher amplitude in the sheet group (4.2 ± 1.3 mV) than in the suspension (1.7 ± 1.2 mV) or CFNG group (1.6 ± 0.8 mV; p < .01). Toluidine blue staining showed that the number of myelinated fibers was significantly higher in the sheet group (2,450 ± 687) than in the suspension (1,645 ± 659) or CFNG group (1,049 ± 307; p < .05). CFNG in combination with ADSC sheets, prepared using temperature‐responsive dishes, promoted axonal outgrowth in autologous nerve grafts and reduced the time to reinnervation.     

Electrospun silk fibroin‐based neural scaffold for bridging a long sciatic nerve gap in dogs

Silk fibroin (SF)‐derived silkworms represent a type of highly biocompatible biomaterial for tissue engineering. We have previously investigated biocompatibility of SF with neural cells isolated from the central nervous system or peripheral nerve system in vitro, and also developed a SF‐based nerve graft conduit or tissue‐engineered nerve grafts by introducing bone marrow mesenchymal stem cells, as support cells, into SF‐based scaffold and evaluated the outcomes of peripheral nerve repair in a rat model. As an extension of the previous study, the electrospun technique was performed here to fabricate SF‐based neural scaffold inserted with silk fibres for bridging a 30‐mm‐long sciatic nerve gap in dogs. Assessments including functional, histological and morphometrical analyses were applied 12 months after surgery. All the results indicated that the SF‐based neural scaffold group achieved satisfactory regenerative outcomes, which were close to those achieved by autologous nerve grafts as the golden‐standard for peripheral nerve repair. Overall, our results raise a potential possibility for the translation of SF‐based electrospun neural scaffolds as an alternative to nerve autografts into the clinic.     

Regenerative effect of adipose tissue‐derived stem cells transplantation using nerve conduit therapy on sciatic nerve injury in rats

This study proposed a biodegradable GGT nerve conduit containing genipin crosslinked gelatin annexed with tricalcium phosphate (TCP) ceramic particles for the regeneration of peripheral nerves. Cytotoxicity tests revealed that GGT‐extracts were non‐toxic and promoted proliferation and neuronal differentiation in the induction of stem cells (i‐ASCs) derived from adipose tissue. Furthermore, the study confirmed the effectiveness of a GGT/i‐ASCs nerve conduit as a guidance channel in the repair of a 10‐mm gap in the sciatic nerve of rats. At eight weeks post‐implantation, walking track analysis showed a significantly higher sciatic function index (SFI) (P < 0.05) in the GGT/i‐ASC group than in the autograft group. Furthermore, the mean recovery index of compound muscle action potential (CMAP) differed significantly between GGT/i‐ASCs and autograft groups (P < 0.05), both of which were significantly superior to the GGT group (P < 0.05). No severe inflammatory reaction in the peripheral nerve tissue at the site of implantation was observed in either group. Histological observation and immunohistochemistry revealed that the morphology and distribution patterns of nerve fibers in the GGT/i‐ASCs nerve conduits were similar to those of the autografts. These promising results achieved through a combination of regenerative cells and GGT nerve conduits suggest the potential value in the future development of clinical applications for the treatment of peripheral nerve injury. Copyright © 2012 John Wiley & Sons, Ltd.     

PLGA artificial nerve conduits with dental pulp cells promote facial nerve regeneration

A number of recent studies have shown the effectiveness of tubulation, using neural progenitor cells or Schwann cells, for promoting nerve regeneration. However, the use of neural cells from other neural donor tissues has potentially serious clinical complications. Therefore, we focused on dental pulp as a new cell source for use in such artificial conditions. Previously, we showed that silicone tubes filled with dental pulp cells (DPCs) promoted facial nerve regeneration in rats. However, the use of silicone tubes requires a secondary removal operation because they may give rise to chronic inflammation and pain. Therefore, to avoid this procedure, a new artificial device was prepared from a degradable poly-DL-lactide-co-glycolide (PLGA) tube containing DPCs, and its effectiveness for repairing gaps in the facial nerves of rats was investigated. A PLGA tube containing rat DPCs embedded in a collagen gel was transplanted into a gap in a rat facial nerve. Five days after transplantation, the facial nerves connected by the PLGA tubes containing DPCs were repaired more quickly than the control nerves. The PLGA tubes were resorbed in vivo and nerve regeneration was observed 2 months after the transplantation. Immunostaining showed that Tuj1-positive axons were present in the regenerated nerves 2 months after transplantation, and osmium-toluidine blue staining showed no mineralization of the regenerated nerves in those tubes containing myelinated fibres after 9 weeks. PLGA tubes filled with DPCs promoted nerve regeneration and were readily resorbed in vivo.     

How chondrogenic are human umbilical cord matrix cells? A comparison to adipose‐derived stem cells

The umbilical cord matrix as well as liposuction material have been demonstrated to contain cells capable of differentiating towards the mesodermal lineage. High availability and low donor site morbidity appear promising for the use of human umbilical cord matrix cells (HUCMs) and adipose‐derived stem cells (ASCs) in cell‐based therapies. In the present study we focused on cartilage regeneration and compared HUCMs and ASCs regarding their potential to differentiate towards the chondrogenic lineage. Cells were isolated by explantation culture or enzymatic digestion, phenotypically characterized by flow cytometry and differentiated as 3D micromass pellets for up to 35 days. Under tested conditions, ASCs demonstrated significantly higher glycosaminoglycan synthesis compared to HUCMs. qRT–PCR data gave evidence that chondrogenic genes are expressed by both ASCs and HUCMs. However, higher expression levels of ASCs suggest that this cell type has higher potential for differentiation towards a cartilage‐like phenotype than HUCMs. In conclusion, both cell types, HUCMs and ASCs, are easily available, possess typical properties of mesenchymal stem cells and are thus promising for cell‐based therapies. However, in terms of cartilage regeneration, ASCs might be more suitable than HUCMs. Copyright © 2009 John Wiley & Sons, Ltd.     

壳聚糖复合导管与人脐带间充质干细胞对神经侧芽分化生长的作用

背景：人脐带间充质干细胞与骨髓间充质干细胞相类似,在特定环境下可以定向分化成神经样细胞,可以按需分泌各种因子,提供神经再生的基质和基础细胞。 目的：研究桥接人脐带间充质干细胞壳聚糖复合神经导管在神经端侧吻合中的作用。 方法：将30只大耳白兔随机均分为3组,切断右后侧腓总神经中部分支,近端结扎,翻转缝合于肌肉内,对照组将腓总神经远断端与胫神经以30°-45°夹角行传统端侧吻合,支架组以同等间隙及夹角桥接壳聚糖导管于胫神经-腓总神经端侧吻合口间,细胞-支架组以同等间隙及夹角桥接填充人脐带间充质干细胞的壳聚糖复合导管于胫神经-腓总神经端侧吻合口间。术后12周行大体观察、神经电生理和抗S-100免疫组织化学检测。 结果与结论：术后12周,细胞-支架组壳聚糖复合神经导管完全降解,神经直径接近正常腓神经,运动神经传导速度快于对照组与支架组（P ＜0.01）;抗S-100免疫组织化学显示,细胞-支架组可见大量棕红色增殖的许旺细胞排列在再生神经纤维周围,支架组与对照组棕红色物质少而稀疏,许旺细胞生长情况较差。表明人脐带间充质干细胞在神经端侧吻合中对神经再生有明显促进作用,对诱导轴芽生长,加快再生纤维生长速度,促进许旺细胞生长及成熟有显著意义。     

无细胞神经移植物复合骨髓间充质干细胞修复大鼠坐骨神经缺损

背景:作者前期试验已成功制备了天然可生物降解的无细胞神经移植物并证明其可促进周围神经再生.目的:无细胞神经移植物复合骨髓间充质干细胞构建组织工程人工神经并观察其修复大鼠坐骨神经缺损促进运动功能恢复的效果.设计、时间及地点:随机对照动物实验,于2008-06/2009-02在辽宁医学院附属第一医院医学组织工程实验室完成.材料:180～200 g成年健康雄性Wistar大鼠,用于制备无细胞神经移植物,100～120 g成年健康雄性Wistar大鼠,用于制备骨髓间充质干细胞,将骨髓间充质干细胞植入并与无细胞神经支架联合培养构建组织工程人工神经.方法:180～200 g成年健康雄性SD大鼠60只构建坐骨神经15 mm缺损模型,随机分成3组,每组20只.①实验组采用组织工程人工神经桥接大鼠坐骨神经缺损.②空白对照组采用组织工程神经支架桥接大鼠坐骨神经缺损.③自体神经对照组采用自体神经移植桥接大鼠坐骨神经缺损.主要观察指标:术后12周通过大体观察、电生理检测、组织学和小腿三头肌湿质量等方法分析评价运动功能恢复情况.结果:①术后12周,实验组大鼠手术侧足趾可以分开,并且可以支撑着地;实验组大鼠再生神经传导速度与自体神经对照组相比,差异无显著性意义.②术后12周,实验组组织化学染色可见腓肠肌内有呈AchE阳性的运动终板整齐地排列于腓肠肌的中上部形成终板带,经结合镀银染色后可见再生的神经束及发出的分支与运动终板相连.③实验组与自体神经对照组胫骨前肌湿质量比差异无显著性意义.结论:无细胞神经移植物复合骨髓间充质干细胞桥接大鼠坐骨神经缺损具有促进其运动功能恢复的作用.     

A laminin‐2‐derived peptide promotes early‐stage peripheral nerve regeneration in a dual‐component artificial nerve graft

The DLTIDDSYWYRI motif (Ln2‐P3) of human laminin‐2 has been reported to promote PC12 cell attachment through syndecan‐1; however, the in vivo effects of Ln2‐P3 have not been studied. In Schwann cells differentiated from skin‐derived precursors, the peptide was effective in promoting cell attachment and spreading in vitro. To examine the effects of Ln2‐P3 in peripheral nerve regeneration in vivo, we developed a dual‐component poly(p‐dioxanone) (PPD)/poly(lactic‐co‐glycolic acid) (PLGA) artificial nerve graft. The novel graft was coated with scrambled peptide or Ln2‐P3 and used to bridge a 10 mm defect in rat sciatic nerves. The dual‐component nerve grafts provided tensile strength comparable to that of a real rat nerve trunk. The Ln2‐P3‐treated grafts promoted early‐stage peripheral nerve regeneration by enhancing the nerve regeneration rate and significantly increased the myelinated fibre density compared with scrambled peptide‐treated controls. These findings indicate that Ln2‐P3, combined with tissue‐engineering scaffolds, has potential biomedical applications in peripheral nerve injury repair. Copyright © 2012 John Wiley & Sons, Ltd.     

Human dental pulp stem cells expressing STRO‐1, c‐kit and CD34 markers in peripheral nerve regeneration

Peripheral nerve injuries are a commonly encountered clinical problem and often result in long‐term functional defects. The application of stem cells able to differentiate in Schwann cell‐like cells in vitro and in vivo, could represent an attractive therapeutic approach for the treatment of nerve injuries. Further, stem cells sources sharing the same embryological origin as Schwann cells might be considered a suitable tool. The aim of this study was to demonstrate the ability of a neuroectodermal subpopulation of human STRO‐1⁺/c‐Kit⁺/CD34⁺ DPSCs, expressing P75^NTR, nestin and SOX‐10, to differentiate into Schwann cell‐like cells in vitro and to promote axonal regeneration in vivo, which led to functional recovery as measured by sustained gait improvement, in animal rat model of peripheral nerve injury. Transplanted human dental pulp stem cells (hDPSCs) engrafted into sciatic nerve defect, as revealed by the positive staining against human nuclei, showed the expression of typical Schwann cells markers, S100b and, noteworthy, a significant number of myelinated axons was detected. Moreover, hDPSCs promoted axonal regeneration from proximal to distal stumps 1 month after transplantation. This study demonstrates that STRO‐1⁺/c‐Kit⁺/CD34⁺ hDPSCs, associated with neural crest derivation, represent a promising source of stem cells for the treatment of demyelinating disorders and might provide a valid alternative tool for future clinical applications to achieve functional recovery after injury or peripheral neuropathies besides minimizing ethical issues. Copyright © 2016 John Wiley & Sons, Ltd.     

神经干细胞与自体筋膜联合修复家兔面神经损伤

目的观察应用神经干细胞和自体筋膜修复面神经损伤的效果。方法 2 2只健康新西兰日系大耳白兔 ,随机分为对照组 (单纯自体筋膜移植 )和治疗组 (自体筋膜 神经干细胞移植 ) ,对照组 8只 ,共 15侧 ;治疗组 14只 ,共 2 0侧。分别于术前、术中(切断前后 )、术后 6周以阈刺激记录其潜伏期。术后 6周取桥接处的再生面神经 ,脱水、石蜡包埋 ,连续切片 (厚度 5 μm ) ,MBP髓鞘染色。半薄和超薄切片 ,分别观察髓鞘的数目和厚度。结果电生理阈刺激下 ,神经潜伏期术前、术中切断前无显著性差异。与术后 6周比较有显著性差异 (P <0 0 5 )。术后 6周取桥接处的再生神经 ,BrdU免疫荧光染色显示 :治疗组有大量BrdU阳性细胞。对照组未见BrdU阳性细胞。MBP免疫组织化学染色显示 :邻片与大量BrdU阳性细胞相对应区有大量MBP阳性细胞 ,横断面为环形或半环形 ,纵断面为连续或不连续的条索状。对照组MBP阳性细胞数目显著减少。半薄和超薄切片显示治疗组的再生纤维以有髓神经纤维为主 ,髓鞘板层结构明暗相间 ,结构清晰 ,轴浆内细胞器丰富。对照组的再生纤维髓鞘发育差 ,但能看到典型的髓鞘板层结构 ,轴浆内细胞器较少。结论神经干细胞和自体筋膜联合应用能显著提高面神经损伤后修复的效果。     

A comparative study of induced pluripotent stem cells generated from frozen, stocked bone marrow- and adipose tissue-derived mesenchymal stem cells

Bone marrow-derived mesenchymal stem cells (BMSCs) and adipose tissue-derived mesenchymal stem cells (AMSCs) have been used clinically for tissue regeneration; however, their proliferation/differentiation potentials are limited. Recently, induced pluripotent stem cells (iPSCs), known to have nearly unlimited potential to proliferate and differentiate into cells of all three germ layers, have gained wide interest in regenerative medicine. Here, we generated iPSCs from frozen-stocked AMSCs and BMSCs and examined their biological characteristics by comparative analyses. Although the iPSCs were more challenging to generate from the BMSCs than the AMSCs, both iPSC populations expressed pluripotent markers, such as stage-specific embryonic antigen (SSEA)-3, SSEA-4, tumour-related antigens (TRAs) TRA-1-60 and TRA-1-81, OCT3/4 and NANOG. Furthermore, both cell populations differentiated well into three germ layer-derived cells, both in vitro and in vivo. These results indicate that iPSCs derived from frozen AMSCs/BMSCs exhibit equally acceptable iPSC characteristics and have potential in clinical applications as an alternative source of autogenous stem cells.     

Engineered neural tissue with Schwann cell differentiated human dental pulp stem cells: potential for peripheral nerve repair?

Despite the spontaneous regenerative capacity of the peripheral nervous system, large gap peripheral nerve injuries (PNIs) require bridging strategies. The limitations and suboptimal results obtained with autografts or hollow nerve conduits in the clinic urge the need for alternative treatments. Recently, we have described promising neuroregenerative capacities of Schwann cells derived from differentiated human dental pulp stem cells (d‐hDPSCs) in vitro . Here, we extended the in vitro assays to show the pro‐angiogenic effects of d‐hDPSCs, such as enhanced endothelial cell proliferation, migration and differentiation. In addition, for the first time we evaluated the performance of d‐hDPSCs in an in vivo rat model of PNI. Eight weeks after transplantation of NeuraWrap? conduits filled with engineered neural tissue (EngNT) containing aligned d‐hDPSCs in 15‐mm rat sciatic nerve defects, immunohistochemistry and ultrastructural analysis revealed ingrowing neurites, myelinated nerve fibres and blood vessels along the construct. Although further research is required to optimize the delivery of this EngNT, our findings suggest that d‐hDPSCs are able to exert a positive effect in the regeneration of nerve tissue in vivo . Copyright © 2017 John Wiley & Sons, Ltd.     

Bone marrow stromal and Schwann cells from adult rats can interact synergistically to aid in peripheral nerve repair even without intercellular contact in vitro

To better understand the use of Schwann cells (SCs) and bone marrow stromal cells (BMSCs) together for nerve repair, we studied whether interactions between these two cell types by diffusible molecules can enhance their utility. In the present study, a co‐culture system was established to allow BMSCs and SCs grow in the same culture medium but without physical contact. Before co‐culture, the adult SCs were expanded until confluent. The adult BMSCs were cultured until P10 with CD29 and CD44 positive but CD45 negative. After 4 days in culture, > 80% of the BMSCs in the co‐culture system showed both GFAP‐ and S‐100‐positive, but < 6% of the BMSCs in control culture system showed both GFAP‐ and S‐100‐positive. Meanwhile, 68.76% of the SCs in co‐culture system showed S‐100‐positive, which was > 42.03% of the SCs in control culture system. Furthermore, the in vivo study also confirmed that differentiated BMSCs exert a more beneficial effect on repairing injured sciatic nerve function and axonal regeneration than undifferentiated BMSCs. These results indicate that the two most widely used cell types for promoting peripheral nerve regeneration may interact synergistically to aid their roles in peripheral nerve repair. Copyright © 2011 John Wiley & Sons, Ltd.     

The effect of age on osteogenic,adipogenic and proliferative potential of female adipose‐derived stem cells

Human adipose tissue is an ideal source of autologous cells that is both plentiful and easily obtainable in large quantities through the simple surgical procedure of liposuction. The stromal vascular fraction of adipose tissue contains a stem cell population, adipose‐derived stem cells (ASCs), capable of adipogenic, osteogenic, myogenic and chondrogenic differentiation. These cells have already been recognized to possess great therapeutic potential in tissue engineering and regeneration. In this study, we sought to determine the effect of donor age on the growth kinetics and differentiation potential of ASCs. For this, ASCs were isolated from liposuctioned adipose tissue obtained from female patients in the age range 20–58 years. Population doubling time was calculated over 2 weeks and differentiation potential was determined by assaying for adipogenesis and osteogenesis. ASCs obtained from older donors appeared to have a slower rate of proliferation, but this relationship was not significant. While adipogenic potential was unrelated to donor age, a distinct relationship between donor age and osteogenic potential was observed. The aetiology of this age‐dependent change in osteogenic potential was not due to any changes in the number of precursors with osteogenic capacity in the adipose sample. These findings have important implications for emerging cell‐based therapeutic strategies, such as tissue engineering, in addition to treatment of various metabolic bone disorders including osteoporosis. Copyright © 2009 John Wiley & Sons, Ltd.     

Effect of adiponectin secreted from adipose‐derived stem cells on bone‐fat balance and bone defect healing

The efficacy of adiponectin (APN) in regulating bone metabolism remains controversial. This study aimed to investigate the role of APN secreted from adipose‐derived stem cells on adipogenesis and osteogenesis. Human APN gene was transfected via recombinant adenovirus into adipose derived stem cells (ASCs) in vitro and were cocultured with bone marrow mesenchymal stem cells (BMSCs) in using a transwell chamber. Adipogenesis was inhibited in APN‐transfected ASCs; in BMSCs, adipogenesis was inhibited, but osteogenesis was promoted in coculture with APN‐transfected ASCs. Next, the same adenovirus construct was transfected into the abdominal adipose tissue of a Sprague Dawley rat in vivo, and then a tibia defect was established in the same rat. We confirmed there was higher gene and protein expression of APN in ASCs and the abdominal adipose tissue of these rat models. Development of adipocytes in abdominal adipose tissue was suppressed, and less new bone was formed in the bone defect area. In conclusion, APN secreted from ASCs could directly inhibit adipogenesis in ASCs and BMSCs and promote osteogenesis in the latter. However, APN overexpression in adipose tissue was inversely associated with bone formation in tibia defects potentially due to decreased levels of circulating bone‐activating hormones.     

Electrophysiological assessment of a peptide amphiphile nanofiber nerve graft for facial nerve repair

Facial nerve injury can cause severe long‐term physical and psychological morbidity. There are limited repair options for an acutely transected facial nerve not amenable to primary neurorrhaphy. We hypothesize that a peptide amphiphile nanofiber neurograft may provide the nanostructure necessary to guide organized neural regeneration. Five experimental groups were compared, animals with (1) an intact nerve, (2) following resection of a nerve segment, and following resection and immediate repair with either a (3) autograft (using the resected nerve segment), (4) neurograft, or (5) empty conduit. The buccal branch of the rat facial nerve was directly stimulated with charge balanced biphasic electrical current pulses at different current amplitudes whereas nerve compound action potentials (nCAPs) and electromygraphic responses were recorded. After 8 weeks, the proximal buccal branch was surgically reexposed and electrically evoked nCAPs were recorded for groups 1–5. As expected, the intact nerves required significantly lower current amplitudes to evoke an nCAP than those repaired with the neurograft and autograft nerves. For other electrophysiologic parameters such as latency and maximum nCAP, there was no significant difference between the intact, autograft, and neurograft groups. The resected group had variable responses to electrical stimulation, and the empty tube group was electrically silent. Immunohistochemical analysis and transmission electron microscopy confirmed myelinated neural regeneration. This study demonstrates that the neuroregenerative capability of peptide amphiphile nanofiber neurografts is similar to the current clinical gold standard method of repair and holds potential as an off‐the‐shelf solution for facial reanimation and potentially peripheral nerve repair.     

Regenerative effects of human embryonic stem cell‐derived neural crest cells for treatment of peripheral nerve injury

Surgical intervention is the current gold standard treatment following peripheral nerve injury. However, this approach has limitations, and full recovery of both motor and sensory modalities often remains incomplete. The development of artificial nerve grafts that either complement or replace current surgical procedures is therefore of paramount importance. An essential component of artificial grafts is biodegradable conduits and transplanted cells that provide trophic support during the regenerative process. Neural crest cells are promising support cell candidates because they are the parent population to many peripheral nervous system lineages. In this study, neural crest cells were differentiated from human embryonic stem cells. The differentiated cells exhibited typical stellate morphology and protein expression signatures that were comparable with native neural crest. Conditioned media harvested from the differentiated cells contained a range of biologically active trophic factors and was able to stimulate in vitro neurite outgrowth. Differentiated neural crest cells were seeded into a biodegradable nerve conduit, and their regeneration potential was assessed in a rat sciatic nerve injury model. A robust regeneration front was observed across the entire width of the conduit seeded with the differentiated neural crest cells. Moreover, the up‐regulation of several regeneration‐related genes was observed within the dorsal root ganglion and spinal cord segments harvested from transplanted animals. Our results demonstrate that the differentiated neural crest cells are biologically active and provide trophic support to stimulate peripheral nerve regeneration. Differentiated neural crest cells are therefore promising supporting cell candidates to aid in peripheral nerve repair.     

Application of marrow mesenchymal stem cell‐derived extracellular matrix in peripheral nerve tissue engineering

To advance molecular and cellular therapy into the clinic for peripheral nerve injury, modification of neural scaffolds with the extracellular matrix (ECM) of peripheral nerves has been established as a promising alternative to direct inclusion of support cells and/or growth factors within a neural scaffold, while cell‐derived ECM proves to be superior to tissue‐derived ECM in the modification of neural scaffolds. Based on the fact that bone marrow mesenchymal stem cells (BMSCs), just like Schwann cells, are adopted as support cells within a neural scaffold, in this study we used BMSCs as parent cells to generate ECM for application in peripheral nerve tissue engineering. A chitosan nerve guidance conduit (NGC) and silk fibroin filamentous fillers were respectively prepared for co‐culture with purified BMSCs, followed by decellularization to stimulate ECM deposition. The ECM‐modified NGC and lumen fillers were then assembled into a chitosan–silk fibroin‐based, BMSC‐derived, ECM‐modified neural scaffold, which was implanted into rats to bridge a 10 mm‐long sciatic nerve gap. Histological and functional assessments after implantation showed that regenerative outcomes achieved by our engineered neural scaffold were better than those achieved by a plain chitosan–silk fibroin scaffold, and suggested the benefits of BMSC‐derived ECM for peripheral nerve repair. Copyright © 2016 John Wiley & Sons, Ltd.