Adult Peripheral Nerve Research Articles

Cultivation of Schwann cells from fresh and non-fresh adult equine peripheral nerves

BackgroundOver the past 25 years, acquired equine polyneuropathy (AEP) has emerged as a neurological disease in Scandinavian horses. This condition is characterized by histopathological features including the presence of Schwann cell (SC) inclusions. Cultivated equine SCs would serve as a valuable resource for investigations of factors triggering this Schwannopathy. Ideally, cells should be sampled for cultivation from fresh nerves immediately after death of the animal, however the availability of fresh material is limited, due to the inconsistent case load and the inherent technical and practical challenges to collection of samples in the field. This study aimed to cultivate SCs from adult equine peripheral nerves and assess their ability to survive in sampled nerve material over time to simulate harvesting of SCs in field situations. New methodsPeripheral nerves from five non-neurological horses were used. After euthanasia, both fresh and non-fresh nerve samples were harvested from each horse. Flow cytometry was employed to confirm the cellular identity and to determine the SC purity. ResultsThe results revealed successful establishment of SC cultures from adult equine peripheral nerves, with the potential to achieve high SC purity from both fresh and non-fresh nerve samples. Comparison with existing methodWhile most SC isolation methods focus on harvest of cells from fresh nerve materials from laboratory animals, our approach highlights the possibility of utilizing SC cultures from field-harvested and transported nerve samples from horses. ConclusionsWe describe a method for isolating SCs with high purity from both fresh and non-fresh peripheral nerves of adult horses.

Schwann cells and myelin in human peripheral nerve: Major protein components vary with age, axon size and pathology.

We examined major protein components of Schwann cells (SCs) and myelin in normal and diseased human peripheral nerves. We evaluated distributions of neural cell adhesion molecule (NCAM), P0 protein (P0) and myelin basic protein (MBP) in frozen sections of 98 sural nerves. Non-myelinating SC in normal adults contained NCAM, but not P0 or MBP. With chronic axon loss, SC without associated axons (Büngner band cells) often co-stained for both NCAM and P0. Onion bulb cells also co-stained for both P0 and NCAM. Infants had many SC with MBP but no P0. All myelin sheaths contained P0. Myelin around large, and some intermediate-sized, axons co-stained for both MBP and P0. Myelin on other intermediate-sized axons had P0, but no MBP. Regenerated axons often had sheaths with MBP, P0 and some NCAM. During active axon degeneration, myelin ovoids often co-stained for MBP, P0 and NCAM. Demyelinating neuropathy patterns included SC (NCAM) loss, and myelin with abnormally distributed, or reduced, P0. Peripheral nerve SC and myelin have varied molecular phenotypes, related to age, axon size and nerve pathology. In normal adult peripheral nerve, myelin has two different patterns of molecular composition. MBP is mostly absent from myelin around a population of intermediate-sized axons, whereas P0 is present in myelin around all axons. Denervated SCs have a molecular signature that differs from normal SC types. With acute denervation, SCs may stain for both NCAM and MBP. Chronically denervated SCs often stain for both NCAM and P0.

Sonographic peripheral nerve cross-sectional area in adults, excluding median and ulnar nerves: A systematic review and meta-analysis.

Although electromyography remains the "gold standard" for assessing and diagnosing peripheral nerve disorders, ultrasound has emerged as a useful adjunct, providing valuable anatomic information. The objective of this study was to conduct a systematic review and meta-analysis evaluating the normative sonographic values for adult peripheral nerve cross-sectional area (CSA). Medline and Cochrane Library databases were systematically searched for healthy adult peripheral nerve CSA, excluding the median and ulnar nerves. Data were meta-analyzed, using a random-effects model, to calculate the mean nerve CSA and its 95% confidence interval (CI) for each nerve at a specific anatomical location (= group). Thirty groups were identified and meta-analyzed, which comprised 16 from the upper extremity and 15 from the lower extremity. The tibial nerve (n=2916 nerves) was reported most commonly, followed by the common fibular nerve (n=2580 nerves) and the radial nerve (n=2326 nerves). Means and 95% confidence interval (CIs) of nerve CSA for the largest number of combined nerves were: radial nerve assessed at the spiral groove (n=1810; mean,5.14 mm2 ; 95% CI,4.33 to 5.96); common fibular nerve assessed at the fibular head (n=1460; mean,10.18 mm2 ; 95% CI,8.91 to 11.45); and common fibular nerve assessed at the popliteal fossa (n=1120; mean,12.90 mm2 ; 95% CI,9.12 to 16.68). Publication bias was suspected, but its influence on the results was minimal. Two hundred thirty mean CSAs from 15 857 adult nerves are included in the meta-analysis. These are further categorized into 30 groups, based on anatomical location, providing a comprehensive reference for the clinician and researcher investigating adult peripheral nerve anatomy.

JNK1-Dependent Phosphorylation of GAP-43 Serine 142 is a Novel Molecular Marker for Axonal Growth.

Mammalian axon growth has mechanistic similarities with axon regeneration. The growth cone is an important structure that is involved in both processes, and GAP-43 (growth associated protein-43kDa) is believed to be the classical molecular marker. Previously, we used growth cone phosphoproteomics to demonstrate that S96 and T172 of GAP-43 in rodents are highly phosphorylated sites that are phosphorylated by c-jun N-terminal protein kinase (JNK). We also revealed that phosphorylated (p)S96 and pT172 antibodies recognize growing axons in the developing brain and regenerating axons in adult peripheral nerves. In rodents, S142 is another putative JNK-dependent phosphorylation site that is modified at a lower frequency than S96 and T172. Here, we characterized this site using a pS142-specific antibody. We confirmed that pS142 was detected by co-expressing mouse GAP-43 and JNK1. pS142 antibody labeled growth cones and growing axons in developing mouse neurons. pS142 was sustained until at least nine weeks after birth in mouse brains. The pS142 antibody could detect regenerating axons following sciatic nerve injury in adult mice. Comparison of amino acid sequences indicated that rodent S142 corresponds to human S151, which is predicted to be a substrate of the MAPK family, which includes JNK. Thus, we confirmed that the pS142 antibody recognized human phospho-GAP-43 using activated JNK1, and also that its immunostaining pattern in neurons differentiated from human induced pluripotent cells was similar to those observed in mice. These results indicate that the S142 residue is phosphorylated by JNK1 and that the pS142 antibody is a new candidate molecular marker for axonal growth in both rodents and human.

Single-Cell Regulatory Network Inference and Clustering Identifies Cell-Type Specific Expression Pattern of Transcription Factors in Mouse Sciatic Nerve.

Advances in single-cell RNA sequencing technologies and bioinformatics methods allow for both the identification of cell types in a complex tissue and the large-scale gene expression profiling of various cell types in a mixture. In this report, we analyzed a single-cell RNA sequencing (scRNA-seq) dataset for the intact adult mouse sciatic nerve and examined cell-type specific transcription factor expression and activity during peripheral nerve homeostasis. In total, we identified 238 transcription factors expressed in nine different cell types of intact mouse sciatic nerve. Vascular smooth muscle cells have the lowest number of transcription factors expressed with 17 transcription factors identified. Myelinating Schwann cells (mSCs) have the highest number of transcription factors expressed, with 61 transcription factors identified. We created a cell-type specific expression map for the identified 238 transcription factors. Our results not only provide valuable information about the expression pattern of transcription factors in different cell types of adult peripheral nerves but also facilitate future studies to understand the function of key transcription factors in the peripheral nerve homeostasis and disease.

Peripheral Nerve-Derived Stem Cell Spheroids Induce Functional Recovery and Repair after Spinal Cord Injury in Rodents.

Stem cell therapy is one of the most promising candidate treatments for spinal cord injury. Research has shown optimistic results for this therapy, but clinical limitations remain, including poor viability, engraftment, and differentiation. Here, we isolated novel peripheral nerve-derived stem cells (PNSCs) from adult peripheral nerves with similar characteristics to neural-crest stem cells. These PNSCs expressed neural-crest specific markers and showed multilineage differentiation potential into Schwann cells, neuroglia, neurons, and mesodermal cells. In addition, PNSCs showed therapeutic potential by releasing the neurotrophic factors, including glial cell-line-derived neurotrophic factor, insulin-like growth factor, nerve growth factor, and neurotrophin-3. PNSC abilities were also enhanced by their development into spheroids which secreted neurotrophic factors several times more than non-spheroid PNSCs and expressed several types of extra cellular matrix. These features suggest that the potential for these PNSC spheroids can overcome their limitations. In an animal spinal cord injury (SCI) model, these PNSC spheroids induced functional recovery and neuronal regeneration. These PNSC spheroids also reduced the neuropathic pain which accompanies SCI after remyelination. These PNSC spheroids may represent a new therapeutic approach for patients suffering from SCI.

Variation in pediatric local anesthetic dosing for peripheral nerve blocks: an analysis from the Pediatric Regional Anesthesia Network (PRAN)

BackgroundVariation of local anesthetic dosing has been reported for adult peripheral nerve blocks (PNBs) and infant caudal blocks. As higher doses of local anesthetics (LA) are potentially associated with increased...

Satellite glial cells promote regenerative growth in sensory neurons

Peripheral sensory neurons regenerate their axon after nerve injury to enable functional recovery. Intrinsic mechanisms operating in sensory neurons are known to regulate nerve repair, but whether satellite glial cells (SGC), which completely envelop the neuronal soma, contribute to nerve regeneration remains unexplored. Using a single cell RNAseq approach, we reveal that SGC are distinct from Schwann cells and share similarities with astrocytes. Nerve injury elicits changes in the expression of genes related to fatty acid synthesis and peroxisome proliferator-activated receptor (PPARα) signaling. Conditional deletion of fatty acid synthase (Fasn) in SGC impairs axon regeneration. The PPARα agonist fenofibrate rescues the impaired axon regeneration in mice lacking Fasn in SGC. These results indicate that PPARα activity downstream of FASN in SGC contributes to promote axon regeneration in adult peripheral nerves and highlight that the sensory neuron and its surrounding glial coat form a functional unit that orchestrates nerve repair.

The maintenance of adult peripheral adult nerve and microvascular networks in the rat mesentery culture model

BackgroundNeurovascular patterning is an emerging area of microvascular research. While overlapping molecular signals highlight links between angiogenesis and neurogenesis, advancing our understanding is limited by a lack of in vitro models containing both systems. One potential model is the rat mesentery culture model, which our laboratory has recently introduced as an ex vivo tool to investigate cellular dynamics during angiogenesis in a microvascular network scenario. The objective of this study was to demonstrate the use of the rat mesentery culture model as an ex vivo platform for maintaining the spatiotemporal relationship between blood vessels and peripheral nerves during angiogenesis in adult microvascular networks. MethodsAdult male Wistar rat mesenteric tissue windows were harvested, rinsed in sterile DPBS and medium and then cultured per group: 1) MEM alone and 2) NBM with NGF and 20 % FBS (nerve culture medium). On day 3 post culture tissues were labeled for endothelial (PECAM) and neural (class III β-tubulin, NG2, tyrosine hydroxylase, CGRP) markers. ResultsIn MEM alone tissues nerve segment degeneration was supported by discontinuous nerve or absence of nerve marker labeling. Nerve presence at the arteriole level and capillary level was maintained for the nerve culture medium group compared to day 0, non-cultured control group (unstimulated). Comparison with existing methods and conclusionsThe results support the use of specific medium types to maintain nerve presence across cultured microvascular networks and implicates the rat mesentery culture model as a novel ex vivo tool for investigating neurovascular patterning in adult tissues.

P75 and neural cell adhesion molecule 1 can identify pathologic Schwann cells in peripheral neuropathies.

ObjectiveMyelinated Schwann cells (SCs) in adult peripheral nerves dedifferentiate into immature cells in demyelinating neuropathies and Wallerian degeneration. This plastic SC change is actively involved in the myelin destruction and clearance as demyelinating SCs (DSCs). In inherited demyelinating neuropathy, pathologically differentiated and dysmyelinated SCs constitute the main nerve pathology.MethodsWe investigated whether this SC plastic status in human neuropathic nerves could be determined by patient sera to develop disease‐relevant serum biomarkers. Based on proteomics analysis of the secreted exosomes from immature SCs, we traced p75 neurotrophin receptor (p75) and neural cell adhesion molecule 1 (NCAM) in the sera of patients with peripheral neuropathy.ResultsEnzyme‐linked immunosorbent assay (ELISA) revealed that p75 and NCAM were subtype‐specifically expressed in the sera of patients with peripheral neuropathy. In conjunction with these ELISA data, pathological analyses of animal models and human specimens suggested that the presence of DSCs in inflammatory neuropathy and of supernumerary nonmyelinating or dysmyelinating SCs in inherited neuropathy could potentially be distinguished by comparing the expression profiles of p75 and NCAM.InterpretationThis study indicates that the identification of disease‐specific pathological SC stages might be a valuable tool for differential diagnosis of peripheral neuropathies.

In situ molecular characterization of endoneurial microvessels that form the blood-nerve barrier in normal human adult peripheral nerves.

The blood-nerve barrier (BNB) formed by tight junction-forming endoneurial microvessels located in the innermost compartment of peripheral nerves, and the perineurium serve to maintain the internal microenvironment required for normal signal transduction. The specific molecular components that define the normal adult human BNB are not fully known. Guided by data derived from the adult human BNB transcriptome, we evaluated the in situ expression of 25 junctional complex, transporter, cell membrane, and cytoskeletal proteins in four histologically normal adult sural nerves by indirect fluorescent immunohistochemistry to determine proteins specifically expressed by restrictive endoneurial microvascular endothelium. Using Ulex Europaeus Agglutinin-1 expression to detect endothelial cells, we ascertained that the selected proteins were uniformly expressed in ≥90% of endoneurial microvessels. P-glycoprotein (also known as adenosine triphosphate-binding cassette subfamily B member 1) and solute carrier family 1 member 1 demonstrated restricted expression by endoneurial endothelium only, with classic tight junction protein claudin-5 also expressed on fenestrated epineurial macrovessels, and vascular-specific adherens junction protein cadherin-5 also expressed by the perineurium. The expression profiles of the selected proteins provide significant insight into the molecular composition of normal adult peripheral nerves. Further work is required to elucidate the human adult BNB molecular signature in order to better understand its development and devise strategies to restore function in peripheral neuropathies.

Myelination key factor krox-20 is downregulated in Schwann cells and murine sciatic nerves infected by Mycobacterium leprae.

Schwann cells (SCs) critically maintain the plasticity of the peripheral nervous system. Peripheral nerve injuries and infections stimulate SCs in order to retrieve homeostasis in neural tissues. Previous studies indicate that Mycobacterium leprae (ML) regulates the expression of key factors related to SC identity, suggesting that alterations in cell phenotype may be involved in the pathogenesis of neural damage in leprosy. To better understand whether ML restricts the plasticity of peripheral nerves, the present study sought to determine the expression of Krox-20, Sox-10, c-Jun and p75NTR in SC culture and mice sciatic nerves, both infected by ML Thai-53 strain. Primary SC cultures were stimulated with two different multiplicities of infection (MOI 100:1; MOI 50:1) and assessed after 7 and 14days. Sciatic nerves of nude mice (NU-Foxn1nu ) infected with ML were evaluated after 6 and 9months. In vitro results demonstrate downregulation of Krox-20 and Sox-10 along with the increase in p75NTR-immunolabelled cells. Concurrently, sciatic nerves of infected mice showed a significant decrease in Krox-20 and increase in p75NTR. Our results corroborate previous findings on the interference of ML in the expression of factors involved in cell maturation, favouring the maintenance of a non-myelinating phenotype in SCs, with possible implications for the repair of adult peripheral nerves.

The regulation of the homeostasis and regeneration of peripheral nerve is distinct from the CNS and independent of a stem cell population.

ABSTRACTPeripheral nerves are highly regenerative, in contrast to the poor regenerative capabilities of the central nervous system (CNS). Here, we show that adult peripheral nerve is a more quiescent tissue than the CNS, yet all cell types within a peripheral nerve proliferate efficiently following injury. Moreover, whereas oligodendrocytes are produced throughout life from a precursor pool, we find that the corresponding cell of the peripheral nervous system, the myelinating Schwann cell (mSC), does not turn over in the adult. However, following injury, all mSCs can dedifferentiate to the proliferating progenitor-like Schwann cells (SCs) that orchestrate the regenerative response. Lineage analysis shows that these newly migratory, progenitor-like cells redifferentiate to form new tissue at the injury site and maintain their lineage, but can switch to become a non-myelinating SC. In contrast, increased plasticity is observed during tumourigenesis. These findings show that peripheral nerves have a distinct mechanism for maintaining homeostasis and can regenerate without the need for an additional stem cell population.This article has an associated ‘The people behind the papers’ interview.

Tonic ATP-mediated growth suppression in peripheral nerve glia requires arrestin-PP2 and is evaded in NF1

Normal Schwann cells (SCs) are quiescent in adult nerves, when ATP is released from the nerve in an activity dependent manner. We find that suppressing nerve activity in adult nerves causes SC to enter the cell cycle. In vitro, ATP activates the SC G-protein coupled receptor (GPCR) P2Y2. Downstream of P2Y2, β-arrestin-mediated signaling results in PP2-mediated de-phosphorylation of AKT, and PP2 activity is required for SC growth suppression. NF1 deficient SC show reduced growth suppression by ATP, and are resistant to the effects of β-arrestin-mediated signaling, including PP2-mediated de-phosphorylation of AKT. In patients with the disorder Neurofibromatosis type 1, NF1 mutant SCs proliferate and form SC tumors called neurofibromas. Elevating ATP levels in vivo reduced neurofibroma cell proliferation. Thus, the low proliferation characteristic of differentiated adult peripheral nerve may require ongoing, nerve activity-dependent, ATP. Additionally, we identify a mechanism through which NF1 SCs may evade growth suppression in nerve tumors.

A longitudinal survey of adult spine and peripheral nerve case entries during neurosurgery residency training.

Currently, there is a lack of research assessing residents' operative experience and caseload variability. The current study utilizes data from the Accreditation Council for Graduate Medical Education (ACGME) case log system to analyze national trends in neurosurgical residents' exposure to adult spinal procedures. Prospectively populated ACGME resident case logs from 2013 to 2017 were retrospectively reviewed. The reported number of spinal procedures was compared to the ACGME minimum requirements for each surgical category pertaining to adult spine surgery. A linear regression analysis was conducted to identify changes in operative caseload by residents graduating during the study period, as well as a one-sample t-test using IBM SPSS software to compare the mean number of procedures in each surgical category to the ACGME required minimums. A mean of 427.42 total spinal procedures were performed throughout residency training for each of the 877 residents graduating between 2013 and 2017. The mean number of procedures completed by graduating residents increased by 19.96 (r2 = 0.95) cases per year. The number of cases in every procedural subspecialty, besides peripheral nerve operations, significantly increased during this time. The two procedural categories with the largest changes were anterior and posterior cervical approaches for decompression/stabilization, which increased by 8.78% per year (r2 = 0.95) and 9.04% per year (r2 = 0.95), respectively. There was also a trend of increasing cases logged for lead resident surgeons and a decline in cases logged for senior resident surgeons. Residents' mean caseloads during residency were found to be vastly greater than the ACGME required minimums: residents performed at least twice as many procedures as the required minimums in every surgical category. Graduating neurosurgical residents reported increasing case volumes for adult spinal cases during this 5-year interval. An increase in logged cases for lead resident surgeons as opposed to senior resident surgeons indicates that residents were logging more cases in which they had a more critical role in the procedure. Moreover, the average resident was noted to perform more than twice the number of procedures required by the ACGME in every surgical category, indicating that neurosurgical residents are getting greater exposure to spine surgery than expected. Given the known correlation between case volume and improved surgical outcomes, this data demonstrates each graduating neurosurgical residency class experiences an augmented training in spine surgery.

Establishment of a myelinating co-culture system with a motor neuron-like cell line NSC-34 and an adult rat Schwann cell line IFRS1.

Co-culture models of neurons and Schwann cells have been utilized for the study of myelination and demyelination in the peripheral nervous system; in most of the previous studies, however, these cells were obtained by primary culture with embryonic or neonatal animals. A spontaneously immortalized Schwann cell line IFRS1 from long-term cultures of adult Fischer rat peripheral nerves has been shown to retain fundamental ability to myelinate neurites in co-cultures with adult rat dorsal root ganglion neurons and nerve growth factor-primed PC12 cells. Our current investigation focuses on the establishment of stable co-culture system with IFRS1 cells and NSC-34 motor neuron-like cells. NSC-34 cells were seeded at a low density (2 × 103/cm2) and maintained for 5-7 days in serum-containing medium supplemented with non-essential amino acids and brain-derived neurotrophic factor (BDNF; 10ng/mL). Upon observation of neurite outgrowth under a phase-contrast microscope, the NSC-34 cells were exposed to an anti-mitotic agent mitomycin C (1 µg/mL) for 12-16h, then co-cultured with IFRS1 cells (2 × 104/cm2), and maintained in serum-containing medium supplemented with ascorbic acid (50µg/mL), BDNF (10ng/mL), and ciliary neurotrophic factor (10ng/mL). Double immunofluorescence staining carried out at day 28 of the co-culture showed myelin protein (P0 or PMP22)-immunoreactive IFRS1 cells surrounding the βIII tubulin-immunoreactive neurites. This co-culture system can be a beneficial tool to study the pathogenesis of motor neuron diseases (e.g., amyotrophic lateral sclerosis, Charcot-Marie-Tooth diseases, and immune-mediated demyelinating neuropathies) and novel therapeutic approaches against them.

Culture and Expansion of Rodent and Porcine Schwann Cells for Preclinical Animal Studies.

Cell-based therapies have become a major focus in preclinical research that leads to clinical application of a therapeutic product. Since 1990, scientists at the Miami Project to Cure Paralysis have generated extensive data demonstrating that Schwann cell (SC) transplantation supports spinal cord repair in animals with spinal cord injury. After preclinical efforts in SC transplantation strategies, efficient methods for procuring large, essentially pure populations of SCs from the adult peripheral nerve were developed for rodent and pig studies. This chapter describes a series of simple procedures to obtain and cryopreserve large cultures of highly purified adult nerve-derived SCs without the need for additional purification steps. This protocol permits the derivation of ≥90% pure rodent and porcine SCs within 2-4weeks of culture.

Viral Transduction of Schwann Cells for Peripheral Nerve Repair.

Schwann cells are the primary inducers of regeneration of the peripheral nervous system. Schwann cells can be isolated from adult peripheral nerves, expanded in large numbers, and genetically transduced by viral vectors in vitro prior to their use in vivo. Here we describe how to use lentiviral vectors to transduce primary Schwann cells in vitro. We also describe how cultured Schwann cells can be used in conjunction with decellularized peripheral nerve sheaths prepared by multiple freeze thawing of peripheral nerve tissue. This process depletes all native cells from the nerve sheath but maintains basal lamina integrity and flexibility. A major advantage of using these decellularized nerve sheaths in repair strategies is that they can be obtained from cadaveric tissue and therefore do not require patient matching because the immune response is generated from the intrinsic cells and not the sheath itself. The patient's own cells can then be used to repopulate the decellularized peripheral nerve sheath. Our technique described in this chapter uses decellularized nerve sheaths which are repopulated with extrinsic Schwann cells previously grown in vitro. The Schwann cells can also be engineered in multiple ways, for example, to secrete bioactive proteins beneficial to axonal regeneration.

Schwann cell Myc-interacting zinc-finger protein 1 without pox virus and zinc finger: epigenetic implications in a peripheral neuropathy.

Functionality of adult peripheral nerves essentially relies on differentiation of Schwann cells during postnatal development, as well as fine-tuned re- and transdifferentiation in response to peripheral nerve injury. Epigenetic histone modifications play a major role during the differentiation of embryonic stem cells and diverse organ specific progenitor cells, yet only little is known about the epigenetic regulation of Schwann cells. Just recently, Fuhrmann et al. reported how the transcription factor Myc-interacting zinc-finger protein 1 (Miz1) might contribute to Schwann cell differentiation through repression of the histone demethylase Kdm8. Here, we discuss the potential novel role of Miz1 in Schwann cell differentiation and give a short overview about previously reported histone modifications underlying peripheral nerve development and response to injury.

Dual Contribution of Mesenchymal Stem Cells Employed for Tissue Engineering of Peripheral Nerves: Trophic Activity and Differentiation into Connective-Tissue Cells.

Adult peripheral nerves in vertebrates can regrow their axons and re-establish function after crush lesion. However, when there is extensive loss of a nerve segment, due to an accident or compressive damage caused by tumors, regeneration is strongly impaired. In order to overcome this problem, bioengineering strategies have been employed, using biomaterials formed by key cell types combined with biodegradable polymers. Many of these strategies are successful, and regenerated nerve tissue can be observed 12 weeks after the implantation. Mesenchymal stem cells (MSCs) are one of the key cell types and the main stem-cell population experimentally employed for cell therapy and tissue engineering of peripheral nerves. The ability of these cells to release a range of different small molecules, such as neurotrophins, growth factors and interleukins, has been widely described and is a feasible explanation for the improvement of nerve regeneration. Moreover, the multipotent capacity of MSCs has been very often challenged with demonstrations of pluripotency, which includes differentiation into any neural cell type. In this study, we generated a biomaterial formed by EGFP-MSCs, constitutively covering microstructured filaments made of poly-ε-caprolactone. This biomaterial was implanted in the sciatic nerve of adult rats, replacing a 12-mm segment, inside a silicon tube. Our results showed that six weeks after implantation, the MSCs had differentiated into connective-tissue cells, but not into neural crest-derived cells such as Schwann cells. Together, present findings demonstrated that MSCs can contribute to nerve-tissue regeneration, producing trophic factors and differentiating into fibroblasts, endothelial and smooth-muscle cells, which compose the connective tissue.