| 1. |
- Armstrong, Stephanie J, et al.
(författare)
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Laminin activates NF-kappaB in Schwann cells to enhance neurite outgrowth.
- 2008
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Ingår i: Neuroscience Letters. - : Elsevier BV. - 0304-3940 .- 1872-7972. ; 439:1, s. 42-6
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Tidskriftsartikel (refereegranskat)abstract
- Extracellular matrix (ECM) molecules and Schwann cells (SCs) are important components of peripheral nerve regeneration. In this study, the role of the transcription factor nuclear factor kappa B (NF-kappaB) in SC activation in response to laminin and the subsequent effect on in vitro neurite outgrowth was investigated. Immunocytochemistry and Western blot analysis showed that compared with poly-d-lysine (PDL), laminin enhanced the phosphorylation of IkappaB and p65 NF-kappaB signalling proteins in SCs. Phospho NF-kappaB-p65 was localised to the nucleus indicating activation of NF-kappaB. To assess the functional effect of NF-kappaB activation, SCs plated on PDL or laminin were pre-treated with NF-kappaB inhibitors, 6-amino-4-(4-phenoxyphenylethylamino)quinazoline (QNZ) or Z-leu-leu-leu-CHO (MG-132) before NG108-15 neuronal cells were seeded on the SC monolayer. After 24h co-culture in the absence of inhibitors, SCs seeded on laminin enhanced the mean number and length of neurites extended by NG108-15 cells (1.87+/-0.13 neurites; 238.74+/-8.53microm) compared with those cultured in the presence of SCs and PDL (1.26+/-0.07 neurites; 157.57+/-9.80microm). At 72h, neurite length had further increased to 321.83+/-6.60microm in the presence of SCs and laminin. Inhibition of NF-kappaB completely abolished the effect of laminin on SC evoked neurite outgrowth at 24h and reduced the enhancement of neurite length by over 60% at 72h. SC proliferation was unaffected by NF-kappaB inhibition suggesting that the NF-kappaB signalling pathway plays a discrete role in the activation of SCs and their neurotrophic potential.
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| 2. |
- di Summa, Pietro G., et al.
(författare)
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Collagen (NeuraGen(®)) nerve conduits and stem cells for peripheral nerve gap repair
- 2014
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Ingår i: Neuroscience Letters. - : Elsevier. - 0304-3940 .- 1872-7972. ; 572, s. 26-31
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Tidskriftsartikel (refereegranskat)abstract
- Collagen nerve guides are used clinically for peripheral nerve defects, but their use is generally limited to lesions up to 3cm. In this study we combined collagen conduits with cells as an alternative strategy to support nerve regeneration over longer gaps. In vitro cell adherence to collagen conduits (NeuraGen(®) nerve guides) was assessed by scanning electron microscopy. For in vivo experiments, conduits were seeded with either Schwann cells (SC), SC-like differentiated bone marrow-derived mesenchymal stem cells (dMSC), SC-like differentiated adipose-derived stem cells (dASC) or left empty (control group), conduits were used to bridge a 1cm gap in the rat sciatic nerve and after 2-weeks immunohistochemical analysis was performed to assess axonal regeneration and SC infiltration. The regenerative cells showed good adherence to the collagen walls. Primary SC showed significant improvement in distal stump sprouting. No significant differences in proximal regeneration distances were noticed among experimental groups. dMSC and dASC-loaded conduits showed a diffuse sprouting pattern, while SC-loaded showed an enhanced cone pattern and a typical sprouting along the conduits walls, suggesting an increased affinity for the collagen type I fibrillar structure. NeuraGen(®) guides showed high affinity of regenerative cells and could be used as efficient vehicle for cell delivery. However, surface modifications (e.g. with extracellular matrix molecule peptides) of NeuraGen(®) guides could be used in future tissue-engineering applications to better exploit the cell potential.
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| 3. |
- Kingham, Paul J, et al.
(författare)
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Notch independent signalling mediates Schwann cell-like differentiation of adipose derived stem cells
- 2009
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Ingår i: Neuroscience Letters. - : Elsevier. - 0304-3940 .- 1872-7972. ; 467:2, s. 164-168
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Tidskriftsartikel (refereegranskat)abstract
- Adipose derived stem cells (ASC) differentiate into a Schwann cell (SC)-like phenotype but the signalling pathways mediating this are unknown. We hypothesised that notch might be involved, given its important role in regulating SC development. Rat ASC were differentiated using bFGF, PDGF, GGF-2 and forskolin. RT-PCR analysis showed that mRNA for notch-1 and notch-2 receptors and the notch responsive gene, hes-1, were expressed throughout the differentiation process whereas jagged-1 a notch ligand, and the hey-1 gene were markedly down-regulated. In contrast delta-1 was up-regulated with differentiation and was strongly expressed by rat primary SC. Treatment of ASC with N-[N-(3,5-difluorophenacetyl-l-alanyl)]-S-phenylglycine t-butyl ester (DAPT), a gamma-secretase inhibitor which blocks notch signalling, had no effect on up-regulation of SC proteins S100 or GFAP during differentiation. Furthermore, when co-cultured with NG108-15 neurons, differentiated ASC cultures treated in the absence or presence of DAPT enhanced neurite outgrowth to similar levels. Differentiated ASC expressed PMP-22 but P0 was only present when co-cultured with dorsal root ganglia neurons. DAPT did not affect the expression of these myelin proteins. Thus, ASC express components of the notch signalling pathway but our studies suggest notch is unlikely to play a role in the neurotrophic activity and myelination capability of ASC differentiated into SC-like cells.
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| 4. |
- McGrath, Aleksandra M, et al.
(författare)
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Fibrin conduit supplemented with human mesenchymal stem cells and immunosuppressive treatment enhances regeneration after peripheral nerve injury
- 2012
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Ingår i: Neuroscience Letters. - : Elsevier. - 0304-3940 .- 1872-7972. ; 516:2, s. 171-176
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Tidskriftsartikel (refereegranskat)abstract
- To address the need for the development of bioengineered replacement of a nerve graft, a novel two component fibrin glue conduit was combined with human mesenchymal stem cells (MSC) and immunosupressive treatment with cyclosporine A. The effects of MSC on axonal regeneration in the conduit and reaction of activated macrophages were investigated using sciatic nerve injury model. A 10mm gap in the sciatic nerve of a rat was created and repaired either with fibrin glue conduit containing diluted fibrin matrix or fibrin glue conduit containing fibrin matrix with MSC at concentration of 80×10(6)cells/ml. Cells were labeled with PKH26 prior to transplantation. The animals received daily injections of cyclosporine A. After 3 weeks the distance of regeneration and area occupied by regenerating axons and ED1 positives macrophages was measured. MSC survived in the conduit and enhanced axonal regeneration only when transplantation was combined with cyclosporine A treatment. Moreover, addition of cyclosporine A to the conduits with transplanted MSC significantly reduced the ED1 macrophage reaction.
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| 5. |
- Reid, Adam J, et al.
(författare)
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Long term peripheral nerve regeneration using a novel PCL nerve conduit
- 2013
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Ingår i: Neuroscience Letters. - : Elsevier. - 0304-3940 .- 1872-7972. ; 544, s. 125-30
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Tidskriftsartikel (refereegranskat)abstract
- The gold standard in surgical management of a peripheral nerve gap is currently autologous nerve grafting. This confers patient morbidity and increases surgical time therefore innovative experimental strategies towards engineering a synthetic nerve conduit are welcome. We have developed a novel synthetic conduit made of poly ε-caprolactone (PCL) that has demonstrated promising peripheral nerve regeneration in short-term studies. This material has been engineered to permit translation into clinical practice and here we demonstrate that histological outcomes in a long-term in vivo experiment are comparable with that of autologous nerve grafting. A 1cm nerve gap in a rat sciatic nerve injury model was repaired with a PCL nerve conduit or an autologous nerve graft. At 18 weeks post surgical repair, there was a similar volume of regenerating axons within the nerve autograft and PCL conduit repair groups, and similar numbers of myelinated axons in the distal stump of both groups. Furthermore, there was evidence of comparable re-innervation of end organ muscle and skin with the only significant difference the lower wet weight of the muscle from the PCL conduit nerve repair group. This study stimulates further work on the potential use of this synthetic biodegradable PCL nerve conduit in a clinical setting.
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