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Chiono V, Descrovi E, Sartori S, Gentile P, Ballarini M, Giorgis F, Ciardelli G. Biomimetic Tailoring of the Surface Properties of Polymers at the Nanoscale: Medical Applications. SCANNING PROBE MICROSCOPY IN NANOSCIENCE AND NANOTECHNOLOGY 2 2011. [DOI: 10.1007/978-3-642-10497-8_22] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
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152
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Gu X, Ding F, Yang Y, Liu J. Construction of tissue engineered nerve grafts and their application in peripheral nerve regeneration. Prog Neurobiol 2010; 93:204-30. [PMID: 21130136 DOI: 10.1016/j.pneurobio.2010.11.002] [Citation(s) in RCA: 416] [Impact Index Per Article: 29.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2010] [Revised: 11/02/2010] [Accepted: 11/23/2010] [Indexed: 01/01/2023]
Abstract
Surgical repair of severe peripheral nerve injuries represents not only a pressing medical need, but also a great clinical challenge. Autologous nerve grafting remains a golden standard for bridging an extended gap in transected nerves. The formidable limitations related to this approach, however, have evoked the development of tissue engineered nerve grafts as a promising alternative to autologous nerve grafts. A tissue engineered nerve graft is typically constructed through a combination of a neural scaffold and a variety of cellular and molecular components. The initial and basic structure of the neural scaffold that serves to provide mechanical guidance and optimal environment for nerve regeneration was a single hollow nerve guidance conduit. Later there have been several improvements to the basic structure, especially introduction of physical fillers into the lumen of a hollow nerve guidance conduit. Up to now, a diverse array of biomaterials, either of natural or of synthetic origin, together with well-defined fabrication techniques, has been employed to prepare neural scaffolds with different structures and properties. Meanwhile different types of support cells and/or growth factors have been incorporated into the neural scaffold, producing unique biochemical effects on nerve regeneration and function restoration. This review attempts to summarize different nerve grafts used for peripheral nerve repair, to highlight various basic components of tissue engineered nerve grafts in terms of their structures, features, and nerve regeneration-promoting actions, and finally to discuss current clinical applications and future perspectives of tissue engineered nerve grafts.
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Affiliation(s)
- Xiaosong Gu
- Jiangsu Key Laboratory of Neuroregeneration, Nantong University, 19 Qixiu Road, Nantong, JS 226001, PR China.
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153
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Controlled delivery of glial cell line-derived neurotrophic factor enhances motor nerve regeneration. J Hand Surg Am 2010; 35:2008-17. [PMID: 21035963 DOI: 10.1016/j.jhsa.2010.08.016] [Citation(s) in RCA: 39] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2010] [Revised: 08/13/2010] [Accepted: 08/18/2010] [Indexed: 02/02/2023]
Abstract
PURPOSE To determine the effect of a motor-specific neurotrophic factor, glial-derived neurotrophic factor (GDNF) on motor nerve regeneration. METHODS We used a nerve conduit filled with a fibrin-based delivery system that provided controlled release of GDNF during nerve regeneration. The motor branch of the rat femoral nerve was used to assess motor nerve regeneration across a 5-mm gap. Four experimental groups (n = 4 to n = 8) were evaluated. These included GDNF with the fibrin-based delivery system (GDNF-DS), fibrin alone, empty conduit (negative control), and nerve isograft (positive control). Nerves were harvested at 5 weeks for analysis by histomorphometry and electron microscopy. RESULTS At 5 mm distal to the conduit or isografts, the GDNF-DS group was not significantly different from the nerve isograft group in the following histomorphometric measures: total nerve fibers, percentage of neural tissue, and nerve density. Both the GDNF-DS and isograft groups had significantly more fibers and a higher percentage of neural tissue than fibrin alone and empty conduit groups. There were no differences in fiber width among all groups. By electron microscopy, the GDNF-DS and isograft groups also demonstrated more organized nerve architecture than the fibrin alone and empty conduit groups. CONCLUSIONS The delivery of GDNF from the fibrin-based delivery system promotes motor nerve regeneration at a level similar to an isograft in the femoral motor nerve model. This study gives insight into the potential beneficial role of GDNF in the treatment of motor nerve injuries.
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154
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Abstract
In the body, cells encounter a complex milieu of signals, including topographical cues, in the form of the physical features of their surrounding environment. Imposed topography can affect cells on surfaces by promoting adhesion, spreading, alignment, morphological changes, and changes in gene expression. Neural response to topography is complex, and it depends on the dimensions and shapes of physical features. Looking toward repair of nerve injuries, strategies are being explored to engineer guidance conduits with precise surface topographies. How neurons and other cell types sense and interpret topography remains to be fully elucidated. Studies reviewed here include those of topography on cellular organization and function as well as potential cellular mechanisms of response.
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Affiliation(s)
- Diane Hoffman-Kim
- Center for Biomedical Engineering and Department of Molecular Pharmacology, Physiology, and Biotechnology, Brown University, Providence, Rhode Island 02912, USA.
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155
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Deumens R, Bozkurt A, Meek MF, Marcus MAE, Joosten EAJ, Weis J, Brook GA. Repairing injured peripheral nerves: Bridging the gap. Prog Neurobiol 2010; 92:245-76. [PMID: 20950667 DOI: 10.1016/j.pneurobio.2010.10.002] [Citation(s) in RCA: 358] [Impact Index Per Article: 25.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/31/2010] [Revised: 09/30/2010] [Accepted: 10/05/2010] [Indexed: 02/06/2023]
Abstract
Peripheral nerve injuries that induce gaps larger than 1-2 cm require bridging strategies for repair. Autologous nerve grafts are still the gold standard for such interventions, although alternative treatments, as well as treatments to improve the therapeutic efficacy of autologous nerve grafting are generating increasing interest. Investigations are still mostly experimental, although some clinical studies have been undertaken. In this review, we aim to describe the developments in bridging technology which aim to replace the autograft. A multi-disciplinary approach is of utmost importance to develop and optimise treatments of the most challenging peripheral nerve injuries.
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Affiliation(s)
- Ronald Deumens
- Department of Anesthesiology, Maastricht University Medical Center, Maastricht, The Netherlands.
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156
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Haastert-Talini K, Schaper-Rinkel J, Schmitte R, Bastian R, Mühlenhoff M, Schwarzer D, Draeger G, Su Y, Scheper T, Gerardy-Schahn R, Grothe C. In Vivo Evaluation of Polysialic Acid as Part of Tissue-Engineered Nerve Transplants. Tissue Eng Part A 2010; 16:3085-98. [DOI: 10.1089/ten.tea.2010.0180] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Affiliation(s)
- Kirsten Haastert-Talini
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neurosciences (ZSN), Hannover, Germany
| | - Janett Schaper-Rinkel
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neurosciences (ZSN), Hannover, Germany
| | - Ruth Schmitte
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
| | - Rode Bastian
- Institute of Technical Chemistry, University of Hannover, Hannover, Germany
| | - Martina Mühlenhoff
- Institute for Cellular Chemistry, Hannover Medical School, Hannover, Germany
| | - David Schwarzer
- Institute for Cellular Chemistry, Hannover Medical School, Hannover, Germany
| | - Gerald Draeger
- Institute of Organic Chemistry, University of Hannover, Hannover, Germany
| | - Yi Su
- Institute of Organic Chemistry, University of Hannover, Hannover, Germany
| | - Thomas Scheper
- Institute of Technical Chemistry, University of Hannover, Hannover, Germany
| | - Rita Gerardy-Schahn
- Center for Systems Neurosciences (ZSN), Hannover, Germany
- Institute for Cellular Chemistry, Hannover Medical School, Hannover, Germany
| | - Claudia Grothe
- Institute of Neuroanatomy, Hannover Medical School, Hannover, Germany
- Center for Systems Neurosciences (ZSN), Hannover, Germany
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157
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Repair of Whole Rabbit Facial Nerve Defects Using Facial Nerve Allografts. J Oral Maxillofac Surg 2010; 68:2196-206. [DOI: 10.1016/j.joms.2009.11.012] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2009] [Revised: 11/06/2009] [Accepted: 11/10/2009] [Indexed: 12/11/2022]
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158
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Lopes-Filho JD, Caldas HC, Santos FCA, Mazzer N, Simões GF, Kawasaki-Oyama RS, Abbud-Filho M, Oliveira AR, Toboga SR, Chueire AG. Microscopic evidences that bone marrow mononuclear cell treatment improves sciatic nerve regeneration after neurorrhaphy. Microsc Res Tech 2010; 74:355-63. [PMID: 20734409 DOI: 10.1002/jemt.20916] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2010] [Accepted: 07/01/2010] [Indexed: 11/10/2022]
Abstract
Cell therapy constitutes a possibility for improving nerve regeneration, increasing the success of nerve repair. We evaluate the use of mononuclear cells in the regeneration of the sciatic nerve after axotomy followed by end-to-end neurorrhaphy. Forty adult male Wistar rats (250-300 g) were divided into four groups: (1) sham, (2) neurorrhaphy: the sciatic nerve was sectioned and repaired using epineural sutures, (3) culture medium: after the suture, received an injection of 10 μL of culture medium into the nerve, and (4) mononuclear cell: after the suture, a concentration of 3 × 10(6) of mononuclear cell was injected in epineurium region. Mononuclear cells were obtained from the bone marrow aspirates and separated by Ficoll-Hypaque method. The histological analyses were performed at the 4th postoperative day. The sciatic functional index, histological, and morphometric analyzes were used to evaluate nerve regeneration at the 6th postoperative week. Six rats were used for immunohistochemical analysis on the 4th postoperative day. In the group 4, on the fourth day, the histological analysis demonstrated a more accelerated degenerative process and an increase of the neurotrophic factors was observed. In the 6th week, all the morphometric results of the group 4 were statistically better compared with groups 2 and 3. There was a statistically significant improvement in the sciatic functional index for group 4 compared with groups 2 and 3. Mononuclear cells stimulated nerve regeneration, most probably by speeding up the Wallerian degeneration process as well as stimulating the synthesis of neurotrophic factors.
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Affiliation(s)
- João D Lopes-Filho
- Department of Orthopaedics and Traumatology, Famerp/Funfarme, São José Rio Preto, SP, Brazil
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159
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BD™ PuraMatrix™ peptide hydrogel seeded with Schwann cells for peripheral nerve regeneration. Brain Res Bull 2010; 83:207-13. [PMID: 20633614 DOI: 10.1016/j.brainresbull.2010.07.001] [Citation(s) in RCA: 47] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2010] [Revised: 05/13/2010] [Accepted: 07/02/2010] [Indexed: 01/25/2023]
Abstract
This study investigated the effects of a membrane conduit filled with a synthetic matrix BD™ PuraMatrix™ peptide (BD) hydrogel and cultured Schwann cells on regeneration after peripheral nerve injury in adult rats. After sciatic axotomy, a 10mm gap between the nerve stumps was bridged using ultrafiltration membrane conduits filled with BD hydrogel or BD hydrogel containing Schwann cells. In control experiments, the nerve defect was bridged using either membrane conduits with alginate/fibronectin hydrogel or autologous nerve graft. Axonal regeneration within the conduit was assessed at 3 weeks and regeneration of spinal motoneurons and recovery of muscle weight evaluated at 16 weeks postoperatively. Schwann cells survived in the BD hydrogel both in culture and after transplantation into the nerve defect. Regenerating axons grew significantly longer distances within the conduits filled with BD hydrogel when compared with the alginate/fibronectin hydrogel and alginate/fibronectin with Schwann cells. Addition of Schwann cells to the BD hydrogel considerably increased regeneration distance with axons crossing the injury gap and entering into the distal nerve stump. The conduits with BD hydrogel showed a linear alignment of nerve fibers and Schwann cells. The number of regenerating motoneurons and recovery of the weight of the gastrocnemius muscle was inferior in BD hydrogel and alginate/fibronectin groups compared with nerve grafting. Addition of Schwann cells did not improve regeneration of motoneurons or muscle recovery. The present results suggest that BD hydrogel with Schwann cells could be used within biosynthetic conduits to increase the rate of axonal regeneration across a nerve defect.
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160
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161
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Sun W, Lin H, Chen B, Zhao W, Zhao Y, Xiao Z, Dai J. Collagen scaffolds loaded with collagen-binding NGF-beta accelerate ulcer healing. J Biomed Mater Res A 2010; 92:887-95. [PMID: 19283824 DOI: 10.1002/jbm.a.32445] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Studies have shown that exogenous nerve growth factor (NGF) accelerates ulcer healing, but the inefficient growth factor delivery system limits its clinical application. In this report, we found that the native human NGF-beta fused with a collagen-binding domain (CBD) could form a collagen-based NGF targeting delivery system, and the CBD-fused NGF-beta could bind to collagen membranes efficiently. Using the rabbit dermal ischemic ulcer model, we have found that this targeting delivery system maintains a higher concentration and stronger bioactivity of NGF-beta on the collagen membranes by promoting peripheral nerve growth. Furthermore, it enhances the rate of ulcer healing through accelerating the re-epithelialization of dermal ulcer wounds and the formation of capillary lumens within the newly formed tissue area. Thus, collagen membranes loaded with collagen-targeting human NGF-beta accelerate ulcer healing efficiently.
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Affiliation(s)
- Wenjie Sun
- Key Laboratory of Molecular Developmental Biology, Institute of Genetics and Developmental Biology, Chinese Academy of Sciences, Beijing, China
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162
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Amado S, Rodrigues JM, Luís AL, Armada-da-Silva PAS, Vieira M, Gartner A, Simões MJ, Veloso AP, Fornaro M, Raimondo S, Varejão ASP, Geuna S, Maurício AC. Effects of collagen membranes enriched with in vitro-differentiated N1E-115 cells on rat sciatic nerve regeneration after end-to-end repair. J Neuroeng Rehabil 2010; 7:7. [PMID: 20149260 PMCID: PMC2829579 DOI: 10.1186/1743-0003-7-7] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2009] [Accepted: 02/11/2010] [Indexed: 01/09/2023] Open
Abstract
Peripheral nerves possess the capacity of self-regeneration after traumatic injury but the extent of regeneration is often poor and may benefit from exogenous factors that enhance growth. The use of cellular systems is a rational approach for delivering neurotrophic factors at the nerve lesion site, and in the present study we investigated the effects of enwrapping the site of end-to-end rat sciatic nerve repair with an equine type III collagen membrane enriched or not with N1E-115 pre-differentiated neural cells. After neurotmesis, the sciatic nerve was repaired by end-to-end suture (End-to-End group), end-to-end suture enwrapped with an equine collagen type III membrane (End-to-EndMemb group); and end-to-end suture enwrapped with an equine collagen type III membrane previously covered with neural cells pre-differentiated in vitro from N1E-115 cells (End-to-EndMembCell group). Along the postoperative, motor and sensory functional recovery was evaluated using extensor postural thrust (EPT), withdrawal reflex latency (WRL) and ankle kinematics. After 20 weeks animals were sacrificed and the repaired sciatic nerves were processed for histological and stereological analysis. Results showed that enwrapment of the rapair site with a collagen membrane, with or without neural cell enrichment, did not lead to any significant improvement in most of functional and stereological predictors of nerve regeneration that we have assessed, with the exception of EPT which recovered significantly better after neural cell enriched membrane employment. It can thus be concluded that this particular type of nerve tissue engineering approach has very limited effects on nerve regeneration after sciatic end-to-end nerve reconstruction in the rat.
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Affiliation(s)
- Sandra Amado
- Centro de Estudos de Ciência Animal (CECA), Instituto de Ciências e Tecnologias Agrárias e Agro-Alimentares (ICETA), Universidade do Porto (UP), Portugal
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163
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Schmitte R, Tipold A, Stein VM, Schenk H, Flieshardt C, Grothe C, Haastert K. Genetically modified canine Schwann cells—In vitro and in vivo evaluation of their suitability for peripheral nerve tissue engineering. J Neurosci Methods 2010; 186:202-8. [DOI: 10.1016/j.jneumeth.2009.11.023] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2009] [Revised: 11/25/2009] [Accepted: 11/26/2009] [Indexed: 10/20/2022]
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164
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Abstract
Peripheral nerve regeneration is a complicated and long-term medical challenge that requires suitable guides for bridging nerve injury gaps and restoring nerve functions. Many natural and synthetic polymers have been used to fabricate nerve conduits as well as luminal fillers for achieving desired nerve regenerative functions. It is important to understand the intrinsic properties of these polymers and techniques that have been used for fabricating nerve conduits. Previously extensive reviews have been focused on the biological functions and in vivo performance of polymeric nerve conduits. In this paper, we emphasize on the structures, thermal and mechanical properties of these naturally derived synthetic polymers, and their fabrication methods. These aspects are critical for the performance of fabricated nerve conduits. By learning from the existing candidates, we can advance the strategies for designing novel polymeric systems with better properties for nerve regeneration.
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165
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Tissue Engineering. Plast Reconstr Surg 2010. [DOI: 10.1007/978-1-84882-513-0_12] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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166
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Kemp SWP, Syed S, Walsh W, Zochodne DW, Midha R. Collagen nerve conduits promote enhanced axonal regeneration, schwann cell association, and neovascularization compared to silicone conduits. Tissue Eng Part A 2009; 15:1975-88. [PMID: 19196132 DOI: 10.1089/ten.tea.2008.0338] [Citation(s) in RCA: 61] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/01/2023] Open
Abstract
Peripheral nerve regeneration within guidance conduits involves a critical association between regenerating axons, Schwann cells (SCs), and neovascularization. However, it is currently unknown if there is a greater association between these factors in nonpermeable versus semipermeable nerve guide conduits. We therefore examined this collaboration in both silicone- and collagen-based nerve conduits in both 5- and 10-mm-injury gaps in rat sciatic nerves. Results indicate that collagen conduits promoted enhanced axonal and SC regeneration and association when compared to silicone conduits in the shorter 5-mm-gap model. In addition, collagen tubes displayed enhanced neovascularization over silicone conduits, suggesting that these three factors are intimately related in successful peripheral nerve regeneration. At later time points (1- and 2-month analysis) in a 10-mm-gap model, collagen tubes displayed enhanced axonal regeneration, myelination, and vascularization when compared to silicone-based conduits. Results from these studies suggest that regenerating cables within collagen-based conduits are revascularized earlier and more completely, which in turn enhances peripheral nerve regeneration through these nerve guides as compared to silicone conduits.
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Affiliation(s)
- Stephen W P Kemp
- Department of Clinical Neuroscience, Faculty of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Canada.
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167
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Schwann cells overexpressing FGF-2 alone or combined with manual stimulation do not promote functional recovery after facial nerve injury. J Biomed Biotechnol 2009; 2009:408794. [PMID: 19830246 PMCID: PMC2760319 DOI: 10.1155/2009/408794] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2009] [Accepted: 07/08/2009] [Indexed: 12/29/2022] Open
Abstract
PURPOSE To determine whether transplantation of Schwann cells (SCs) overexpressing different isoforms of fibroblast growth factor 2 (FGF-2) combined with manual stimulation (MS) of vibrissal muscles improves recovery after facial nerve transection in adult rat. PROCEDURES Transected facial nerves were entubulated with collagen alone or collagen plus naïve SCs or transfected SCs. Half of the rats received daily MS. Collateral branching was quantified from motoneuron counts after retrograde labeling from 3 facial nerve branches. Quality assessment of endplate reinnervation was combined with video-based vibrissal function analysis. RESULTS There was no difference in the extent of collateral axonal branching. The proportion of polyinnervated motor endplates for either naïve SCs or FGF-2 over-expressing SCs was identical. Postoperative MS also failed to improve recovery. CONCLUSIONS Neither FGF-2 isoform changed the extent of collateral branching or polyinnervation of motor endplates; furthermore, this motoneuron response could not be overridden by MS.
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168
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Abstract
Bridging nerve gaps with suitable grafts is a major clinical problem. The autologous nerve graft is considered to be the gold standard, providing the best functional results; however, donor site morbidity is still a major disadvantage. Various attempts have been made to overcome the problems of autologous nerve grafts with artificial nerve tubes, which are “ready-to-use” in almost every situation. A wide range of materials have been used in animal models but only few have been applied to date clinically, where biocompatibility is an inevitable prerequisite. This review gives an idea about artificial nerve tubes with special focus on their biocompatibility in animals and humans.
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Affiliation(s)
- Felix Stang
- Department of Plastic, Reconstructive and Hand Surgery, University of Luebeck, 23538 Luebeck, Germany
- Author to whom correspondence should be addressed; E-Mail: ; Tel.: +49-451-5002061; Fax: +49-451-5002190
| | - Gerburg Keilhoff
- Institute of Biochemistry and Cell Biology, University of Magdeburg, 39120 Magdeburg, Germany; E-Mail:
| | - Hisham Fansa
- Department of Plastic, Reconstructive and Aesthetic Surgery, Hand Surgery, Klinikum Bielefeld-Mitte, 33604 Bielefeld, Germany; E-Mail:
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169
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The synaptic remodeling between regenerated perforant pathway and granule cells in slice culture. Cell Mol Neurobiol 2009; 30:309-16. [PMID: 19757022 DOI: 10.1007/s10571-009-9454-7] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/09/2009] [Accepted: 08/28/2009] [Indexed: 10/20/2022]
Abstract
In order to understand the synaptic remodeling in the course of axonal regeneration, the synaptic remodeling of the perforant path in hippocampus was investigated in the present study with entorhino-hippocampal coculture, DiI DiOlistic assay and transmission electron microscopy. The results showed that the regeneration of the perforant pathway occurred in entorhino-hippocampal slice coculture, and putative synaptic contacts formed between the regenerated fibers and dendritic spines of granule cells. Ultrastructural analysis confirmed the formation of new synaptic contacts. In conclusion, the synaptic formation implicated in the neuroregeneration could integrate into the network in CNS.
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170
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Walsh S, Biernaskie J, Kemp SWP, Midha R. Supplementation of acellular nerve grafts with skin derived precursor cells promotes peripheral nerve regeneration. Neuroscience 2009; 164:1097-107. [PMID: 19737602 DOI: 10.1016/j.neuroscience.2009.08.072] [Citation(s) in RCA: 95] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2009] [Revised: 08/04/2009] [Accepted: 08/28/2009] [Indexed: 12/17/2022]
Abstract
Introduction of autologous stem cells into the site of a nerve injury presents a promising therapy to promote axonal regeneration and remyelination following peripheral nerve damage. Given their documented ability to differentiate into Schwann cells (SCs) in vitro, we hypothesized that skin-derived precursor cells (SKPs) could represent a clinically-relevant source of transplantable cells that would enhance nerve regeneration following peripheral nerve injury. In this study, we examined the potential for SKP-derived Schwann cells (SKP-SCs) or nerve-derived SCs to improve nerve regeneration across a 12 mm gap created in the sciatic nerve of Lewis rats bridged by a freeze-thawed nerve graft. Immunohistology after 4 weeks showed survival of both cell types and early regeneration in SKP seeded grafts was comparable to those seeded with SCs. Histomorphometrical and electrophysiological measurements of cell-treated nerve segments after 8 weeks survival all showed significant improvement as compared to diluent controls. A possible mechanistic explanation for the observed results of improved regenerative outcomes lies in SKP-SCs' ability to secrete bioactive neurotrophins. We therefore conclude that SKPs represent an easily accessible, autologous source of stem cells for transplantation therapies which act as functional Schwann cells and show great promise in improving regeneration following nerve injury.
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Affiliation(s)
- S Walsh
- Department of Clinical Neuroscience and Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Heritage Medical Research Building 109-3330 Hospital Drive NW, Calgary, AB, Canada T2N 4N1.
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171
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Kokai LE, Lin YC, Oyster NM, Marra KG. Diffusion of soluble factors through degradable polymer nerve guides: Controlling manufacturing parameters. Acta Biomater 2009; 5:2540-50. [PMID: 19369123 DOI: 10.1016/j.actbio.2009.03.009] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2008] [Revised: 02/09/2009] [Accepted: 03/09/2009] [Indexed: 11/30/2022]
Abstract
Nerve guides are cylindrical conduits of either biologically based or synthetic materials that are used to bridge nerve defects. While it is well known that a critical aspect of nerve regeneration is the delivery of oxygen and nutrients to the surviving nerve tissue, several guide parameters that determine the permeability of nerve guides to nutrients are often overlooked. We have reproducibly manufactured poly(caprolactone) (PCL) nerve guides of tailored porosity percentage, wall thickness and pore diameter through a dip-coating/salt-leaching technique. In this study, these three parameters were varied to measure the response of glucose and lysozyme diffusion through the guide wall. In addition, nerve guide permeability following protein fouling studies was examined. Based on the results from this study, it was determined that at high porosity percentages (80%), decreasing the pore diameter (10-38microm) was a measurable method of decreasing the lysozyme permeability of PCL nerve guides while not creating a loss of glucose permeability. PCL fouling studies were used to fine-tune the desirable nerve guide wall thickness. Results indicated that nerve guides 0.6mm thick decreased the loss of lysozyme to almost 10% without significantly diminishing glucose (nutrient) permeability. These results will be utilized to optimize nerve guide parameters for future in vivo applications.
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Affiliation(s)
- Lauren E Kokai
- Department of Bioengineering, University of Pittsburgh, Pittsburgh, PA 15261, USA
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172
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Chang JY, Ho TY, Lee HC, Lai YL, Lu MC, Yao CH, Chen YS. Highly Permeable Genipin-Cross-linked Gelatin Conduits Enhance Peripheral Nerve Regeneration. Artif Organs 2009; 33:1075-85. [DOI: 10.1111/j.1525-1594.2009.00818.x] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/11/2023]
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173
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Preparation and Integration of Human Amnion Nerve Conduits Using a Light-Activated Technique. Plast Reconstr Surg 2009; 124:428-437. [DOI: 10.1097/prs.0b013e3181af010c] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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174
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Whitlock EL, Tuffaha SH, Luciano JP, Yan Y, Hunter DA, Magill CK, Moore AM, Tong AY, Mackinnon SE, Borschel GH. Processed allografts and type I collagen conduits for repair of peripheral nerve gaps. Muscle Nerve 2009; 39:787-99. [DOI: 10.1002/mus.21220] [Citation(s) in RCA: 311] [Impact Index Per Article: 20.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
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175
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Chiono V, Vozzi G, Vozzi F, Salvadori C, Dini F, Carlucci F, Arispici M, Burchielli S, Di Scipio F, Geuna S, Fornaro M, Tos P, Nicolino S, Audisio C, Perroteau I, Chiaravalloti A, Domenici C, Giusti P, Ciardelli G. Melt-extruded guides for peripheral nerve regeneration. Part I: Poly(ε-caprolactone). Biomed Microdevices 2009; 11:1037-50. [DOI: 10.1007/s10544-009-9321-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023]
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176
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Abstract
OBJECTIVE This review will describe the novel contributions to the field of nerve repair from the emerging disciplines of microtechnology and nanotechnology. METHOD This broad review will cover the advances described in the literature of the medical and biological fields and the engineering and physical sciences. The authors have also included their own work in this field. DISCUSSION Microtechnology and nanotechnology are providing two fundamentally different pathways for pursuing nerve repair: (1) microstructured scaffolds to promote regeneration and (2) direct repair by reconnecting axons. In the first instance, many of the traditional techniques for microfabrication of microelectronics have been applied to the development of implantable tissue scaffolds with precisely formed architectures. Combined with nanotechnological capabilities to control their surface chemistries, these tissue constructs have been designed to create a microenvironment within nerve tissue to optimally promote the outgrowth of neurites. With some initial successes in animal models, these next generation tissue scaffolds may provide a marked improvement over traditional nerve grafts in the ability to overcome nerve degenerative processes and to coax nerve regeneration leading to restoration of at least some nerve function. A second, completely different repair strategy aims to directly repair nerves at the microscale by acutely reconnecting severed or damaged axons immediately after injury and potentially forestalling the usual downstream degenerative processes. This strategy will take advantage of the traditional capabilities of microfabrication to create microelectromechanical systems that will serve as ultramicrosurgical tools that can operate at the micron scale and reliably manipulate individual axons without incurring damage. To bring about some restoration of a nerve's function, axon repair will have to be performed repetitively on a large scale and soon after injury. Development work is currently underway to bring about the feasibility of this technique. CONCLUSION With the emergence of microtechnology and nanotechnology, new methods for repairing nerves are being explored and developed. There have been two fundamental benefits from the technologies of the ultrasmall scale: (1) enhancement of regeneration using new tissue scaffold materials and architecture; (2) direct repair of nerves at the scale of single neurons and axons.
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Affiliation(s)
- Wesley C Chang
- Department of Ophthalmology, University of California, San Francisco, CA 94143, USA.
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177
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Kemp SWP, Walsh SK, Midha R. Growth factor and stem cell enhanced conduits in peripheral nerve regeneration and repair. Neurol Res 2009; 30:1030-8. [PMID: 19079977 DOI: 10.1179/174313208x362505] [Citation(s) in RCA: 67] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
OBJECTIVE Despite the capacity for spontaneous axonal regeneration, recovery after severe peripheral nerve injury remains variable and often very poor. In addition, autologous nerve grafts, considered to be the 'gold standard' in nerve repair technique, are plagued by restricted donor tissue availability and donor site morbidity. Our primary objective is to highlight new and emerging methods of nerve repair, which have the potential to significantly improve both the functional and behavioral outcome after clinical nerve injury. METHODS A critical analysis of nerve injury and regeneration literature concentrating on outcome measures from both immediate and chronically denervated experimental works was conducted. RESULTS Results of numerous works employing both growth factor and stem cell enhanced nerve guidance conduits have shown encouraging results. However, further research is needed to optimize guidance conduit dynamics, bioavailability and delivery of both growth factors and stem cells to enhance peripheral nerve regeneration and functional recovery. DISCUSSION This review discusses current animal and clinical growth factor and stem cell studies, specifically focusing on future bio-engineering approaches in developing a nerve guidance conduit in the future.
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Affiliation(s)
- Stephen W P Kemp
- Department of Clinical Neuroscience, Faculty of Medicine, Hotchkiss Brain Institute, University of Calgary, Calgary, Alta, Canada.
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178
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Luís AL, Rodrigues JM, Geuna S, Amado S, Shirosaki Y, Lee JM, Fregnan F, Lopes MA, Veloso AP, Ferreira AJ, Santos JD, Armada-Da-silva PAS, Varejão ASP, Maurício AC. Use of PLGA 90:10 scaffolds enriched with in vitro-differentiated neural cells for repairing rat sciatic nerve defects. Tissue Eng Part A 2009; 14:979-93. [PMID: 18447635 DOI: 10.1089/ten.tea.2007.0273] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Poly(lactic-co-glycolic acid) (PLGA) nerve tube guides, made of a novel proportion (90:10) of the two polymers, poly(L-lactide): poly(glycolide) and covered with a neural cell line differentiated in vitro, were tested in vivo for promoting nerve regeneration across a 10-mm gap of the rat sciatic nerve. Before in vivo testing, the PLGA 90:10 tubes were tested in vitro for water uptake and mass loss and compared with collagen sheets. The water uptake of the PLGA tubes was lower, and the mass loss was more rapid and higher than those of the collagen sheets when immersed in phosphate-buffered saline (PBS) solution. The pH values of immersing PBS did not change after soaking the collagen sheets and showed to be around 7.4. On the other hand, the pH values of PBS after soaking PLGA tubes decreased gradually during 10 days reaching values around 3.5. For the in vivo testing, 22 Sasco Sprague adult rats were divided into four groups--group 1: gap not reconstructed; group 2: gap reconstructed using an autologous nerve graft; group 3: gap reconstructed with PLGA 90:10 tube guides; group 4: gap reconstructed with PLGA 90:10 tube guides covered with neural cells differentiated in vitro. Motor and sensory functional recovery was evaluated throughout a healing period of 20 weeks using sciatic functional index, static sciatic index, extensor postural thrust, withdrawal reflex latency, and ankle kinematics. Stereological analysis was carried out on regenerated nerve fibers. Both motor and sensory functions improved significantly in the three experimental nerve repair groups, although the rate and extent of recovery was significantly higher in the group where the gap was reconstructed using the autologous graft. The presence of neural cells covering the inside of the PLGA tube guides did not make any difference in the functional recovery. By contrast, morphometric analysis showed that the introduction of N1E-115 cells inside PLGA 90:10 tube guides led to a significant lower number and size of regenerated nerve fibers, suggesting thus that this approach is not adequate for promoting peripheral nerve repair. Further studies are warranted to assess the role of other cellular systems as a foreseeable therapeutic strategy in peripheral nerve regeneration.
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Affiliation(s)
- Ana L Luís
- Centro de Estudos de Ciência Animal (CECA), Instituto de Ciências e Tecnologias Agrárias e Agro-Alimentares (ICETA), Universidade do Porto, Vairão, Portugal
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179
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Kempton LB, Gonzalez MH, Leven RM, Hughes WF, Beddow S, Santhiraj Y, Archibald SJ, El Hassan B, Shott S, Kerns JM. Assessment of Axonal Growth into Collagen Nerve Guides Containing VEGF-Transfected Stem Cells in Matrigel. Anat Rec (Hoboken) 2009; 292:214-24. [DOI: 10.1002/ar.20844] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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180
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Characterisation of human mesenchymal stem cells following differentiation into Schwann cell-like cells. Neurosci Res 2009; 64:41-9. [PMID: 19428682 DOI: 10.1016/j.neures.2009.01.010] [Citation(s) in RCA: 79] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2008] [Revised: 01/07/2009] [Accepted: 01/16/2009] [Indexed: 11/22/2022]
Abstract
Cell-based therapies provide a clinically applicable and available alternative to nerve autografts. Our previous studies have characterised rat-derived mesenchymal stem cells (MSC) and here we have investigated the phenotypic, molecular and functional characteristics of human-derived MSC (hMSC) differentiated along a Schwann cell lineage. The hMSC were isolated from healthy human donors and the identity of the undifferentiated hMSC was confirmed by the detection of MSC specific cells surface markers. The hMSC were differentiated along a glial cell lineage using an established cocktail of growth factors including glial growth factor-2. Following differentiation, the hMSC expressed the key Schwann cell (SC) markers at both the transcriptional and translational level. More importantly, we show the functional effect of hMSC on neurite outgrowth using an in vitro co-culture model system with rat-derived primary sensory neurons. The number of DRG sprouting neurites was significantly enhanced in the presence of differentiated hMSC; neurite length and density (branching) were also increased. These results provide evidence that hMSC can undergo molecular, morphological and functional changes to adopt a SC-like behaviour and, therefore, could be suitable as SC substitutes for nerve repair in clinical applications.
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181
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Ronchi G, Nicolino S, Raimondo S, Tos P, Battiston B, Papalia I, Varejão ASP, Giacobini-Robecchi MG, Perroteau I, Geuna S. Functional and morphological assessment of a standardized crush injury of the rat median nerve. J Neurosci Methods 2009; 179:51-7. [PMID: 19428511 DOI: 10.1016/j.jneumeth.2009.01.011] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/14/2008] [Revised: 01/10/2009] [Accepted: 01/13/2009] [Indexed: 12/25/2022]
Abstract
The availability of effective experimental models for investigating nerve regeneration and designing new strategies for promoting this unique repair process is important. The aim of this study was to standardize a rat median nerve crush injury model using a non-serrated clamp exerting a compression force of 17.02 MPa for a duration of 30s. Results showed that functional recovery, evaluated by grasping test, was already detectable at day-12 and progressively increased until day-28 after which animal performance plateaued until the end of testing (day-42), reaching a range of 75-80% of pre-operative values. Morphological analysis on the median nerve segments, distal to the crush lesion, which were withdrawn at the end of the experiment showed that regenerated nerve fibers are significantly more numerous and densely packed; they are also smaller and have a thinner myelin sheath compared to controls. Together, these results provide a baseline characterization of the crush median nerve injury experimental model for its employment in the investigation of nerve regeneration research, especially when a reproducible regeneration process is required, such as for the study of biological mechanisms of peripheral nerve fiber regeneration or development of new therapeutic agents for promoting posttraumatic nerve repair.
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Affiliation(s)
- G Ronchi
- Department of Animal and Human Biology, University of Turin, Italy
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182
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Chiono V, Tonda-Turo C, Ciardelli G. Chapter 9: Artificial scaffolds for peripheral nerve reconstruction. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2009; 87:173-98. [PMID: 19682638 DOI: 10.1016/s0074-7742(09)87009-8] [Citation(s) in RCA: 54] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Posttraumatic peripheral nerve repair is one of the major challenges in restorative medicine and microsurgery. Despite the recent progresses in the field of tissue engineering, functional recovery after severe nerve lesions is generally partial and unsatisfactory. Autograft is still the best method to treat peripheral nerve lesions, although it has several drawbacks and does not allow complete functional recovery. Full recovery of nerve functionality could ideally be achieved by proper guiding axon regeneration toward the original target tissues, through the use of purposely engineered artificial nerve guidance channels (NGCs). In the last decade, artificial NGCs have been produced using a variety of both natural and synthetic, biodegradable and nonbiodegradable polymers. Several techniques have been developed to obtain porous and nonporous NGCs and to realize and incorporate bioactive fillers for NGCs. Some of the developed products have been approved for clinical applications. Many other NGC typologies have been object of interest and are currently under investigation. The current trend of nerve tissue engineering is the realization of biomimetic NGCs, providing chemotactic, topological, and haptotactic signalling to cells, respectively by surface functionalization with cell binding domains, the use of internal-oriented matrices/fibres and the sustained release of neurotrophic factors. The present contribution provides a balanced integration of the most recent achievements of tissue engineering in the field of peripheral nerve repair. By an accurate evaluation of the status of research, the review delineates the most promising directions to which research should address for consistent progress in the field of peripheral nerve repair.
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Affiliation(s)
- Valeria Chiono
- Department of Mechanics, Politecnico di Torino, Torino, Italy
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183
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Merolli A, Rocchi L, Catalano F, Planell J, Engel E, Martinez E, Sbernardori MC, Marceddu S, Tranquilli Leali P. In vivo regeneration of rat sciatic nerve in a double-halved stitch-less guide: A pilot-study. Microsurgery 2009; 29:310-8. [DOI: 10.1002/micr.20622] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/29/2022]
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184
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Kofron CM, Fong VJ, Hoffman-Kim D. Neurite outgrowth at the interface of 2D and 3D growth environments. J Neural Eng 2008; 6:016002. [DOI: 10.1088/1741-2560/6/1/016002] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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185
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Functional recovery after peripheral nerve injury and implantation of a collagen guide. Biomaterials 2008; 30:363-73. [PMID: 18929405 DOI: 10.1016/j.biomaterials.2008.09.043] [Citation(s) in RCA: 115] [Impact Index Per Article: 7.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2008] [Accepted: 09/10/2008] [Indexed: 11/21/2022]
Abstract
Although surgery techniques improved over the years, the clinical results of peripheral nerve repair remain unsatisfactory. In the present study, we compare the results of a collagen nerve guide conduit to the standard clinical procedure of nerve autografting to promote repair of transected peripheral nerves. We assessed behavioral and functional sensori-motor recovery in a rat model of peroneal nerve transection. A 1cm segment of the peroneal nerve innervating the Tibialis anterior muscle was removed and immediately replaced by a new biodegradable nerve guide fabricated from highly purified type I+III collagens derived from porcine skin. Four groups of animals were included: control animals (C, n=12), transected animals grafted with either an autologous nerve graft (Gold Standard; GS, n=12) or a collagen tube filled with an acellular skeletal muscle matrix (Tube-Muscle; TM, n=12) or an empty collagen tube (Collagen-Tube; CT, n=12). We observed that 1) the locomotor recovery pattern, analyzed with kinetic parameters and peroneal functional index, was superior in the GS and CT groups; 2) a muscle contraction was obtained in all groups after stimulation of the proximal nerve but the mechanical muscle properties (twitch and tetanus threshold) parameters indicated a fast to slow fiber transition in all operated groups; 3) the muscular atrophy was greater in animals from TM group; 4) the metabosensitive afferent responses to electrically induced fatigue and to two chemical agents (KCl and lactic acid) was altered in GS, CT and TM groups; 5) the empty collagen tube supported motor axonal regeneration. Altogether, these data indicate that motor axonal regeneration and locomotor recovery can be obtained with the insertion of the collagen tube RevolNerv. Future studies may include engineered conduits that mimic as closely as possible the internal organization of uninjured nerve.
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186
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Casha S, Yong VW, Midha R. Minocycline for axonal regeneration after nerve injury: A double-edged sword. Exp Neurol 2008; 213:245-8. [DOI: 10.1016/j.expneurol.2008.06.016] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2008] [Revised: 06/26/2008] [Accepted: 06/27/2008] [Indexed: 10/21/2022]
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187
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O'Toole M, Latham R, Baqri RM, Miller KE. Modeling mitochondrial dynamics during in vivo axonal elongation. J Theor Biol 2008; 255:369-77. [PMID: 18845167 DOI: 10.1016/j.jtbi.2008.09.009] [Citation(s) in RCA: 48] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2008] [Revised: 09/03/2008] [Accepted: 09/04/2008] [Indexed: 01/05/2023]
Abstract
Many models of axonal elongation are based on the assumption that the rate of lengthening is driven by the production of cellular materials in the soma. These models make specific predictions about transport and concentration gradients of proteins both over time and along the length of the axon. In vivo, it is well accepted that for a particular neuron the length and rate of growth are controlled by the body size and rate of growth of the animal. In terms of modeling axonal elongation this radically changes the relationships between key variables. It raises fundamental questions. For example, during in vivo lengthening is the production of material constant or does it change over time? What is the density profile of material along the nerve during in vivo elongation? Does density change over time or vary along the nerve? To answer these questions we measured the length, mitochondrial density, and estimated the half-life of mitochondria in the axons of the medial segmental nerves of 1st, 2nd, and 3rd instar Drosophila larvae. The nerves were found to linearly increase in length at an average rate of 9.24 microm h(-1) over the 96 h period of larval life. Further, mitochondrial density increases over this period at an average rate of 4.49x10(-3) (mitochondria microm(-1))h(-1). Mitochondria in the nerves had a half-life of 35.2h. To account for the distribution of the mitochondria we observe, we derived a mathematical model which suggests that cellular production of mitochondria increases quadratically over time and that a homeostatic mechanism maintains a constant density of mitochondria along the nerve. These data suggest a complex relationship between axonal length and mass production and that the neuron may have an "axonal length sensor."
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Affiliation(s)
- Matthew O'Toole
- Department of Mathematics, Michigan State University, A-106 Wells Hall, East Lansing, MI 48824-1115, USA
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188
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Bozkurt A, Deumens R, Scheffel J, O’Dey D, Weis J, Joosten E, Führmann T, Brook G, Pallua N. CatWalk gait analysis in assessment of functional recovery after sciatic nerve injury. J Neurosci Methods 2008; 173:91-8. [DOI: 10.1016/j.jneumeth.2008.05.020] [Citation(s) in RCA: 123] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2008] [Revised: 05/23/2008] [Accepted: 05/27/2008] [Indexed: 11/16/2022]
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189
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de Ruiter GC, Spinner RJ, Malessy MJ, Moore MJ, Sorenson EJ, Currier BL, Yaszemski MJ, Windebank AJ. ACCURACY OF MOTOR AXON REGENERATION ACROSS AUTOGRAFT, SINGLE-LUMEN, AND MULTICHANNEL POLY(LACTIC-CO-GLYCOLIC ACID) NERVE TUBES. Neurosurgery 2008. [DOI: 10.1227/01.neu.0000319521.28683.75] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022] Open
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190
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Pfister LA, Alther E, Papaloïzos M, Merkle HP, Gander B. Controlled nerve growth factor release from multi-ply alginate/chitosan-based nerve conduits. Eur J Pharm Biopharm 2008; 69:563-72. [DOI: 10.1016/j.ejpb.2008.01.014] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2007] [Revised: 12/21/2007] [Accepted: 01/15/2008] [Indexed: 11/28/2022]
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191
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Tos P, Ronchi G, Nicolino S, Audisio C, Raimondo S, Fornaro M, Battiston B, Graziani A, Perroteau I, Geuna S. Employment of the mouse median nerve model for the experimental assessment of peripheral nerve regeneration. J Neurosci Methods 2008; 169:119-27. [DOI: 10.1016/j.jneumeth.2007.11.030] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2007] [Revised: 11/26/2007] [Accepted: 11/28/2007] [Indexed: 01/27/2023]
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