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ABSTRACT: Increasing evidence has shown that adipose-derived stem cells (ASCs) could transdifferentiate into Schwann cell (SC)-like cells to enhance nerve regeneration, suggesting potential new cell-based transplantation therapy for peripheral nerve injuries and neurodegenerative disorders. For implementation of these results to the clinical setting, it is of great importance to establish the differentiation of human ASCs (hASCs) into a SC phenotype. In this study, we studied hASCs obtained from subcutaneous fat tissue of healthy donors. By a mixture of glial growth factors we differentiated them into Schwann cell-like cells (dhASCs). We then assessed their ability to act as Schwann cells in vitro and in vivo and also compared them with primary human Schwann cells (hSCs). Enzyme-linked immunosorbent assay showed that dhASCs secreted brain-derived neurotrophic factor (BDNF) /nerve growth factor (NGF) at a comparable level, and glial cell-derived neurotrophic factor (GDNF) at a level even higher than hSCs, whereas undifferentiated hASCs (uhASCs) secreted low levels of these neurotrophic factors. In co-culture with NG108-15 neuronal cells we found that both dhASCs and hSCs significantly increased the percentage of cells with neurites, the neurite length, and the number of neurites per neuron, whereas uhASCs increased only the percentage of cells with neurites. Finally, we transplanted GFP-labeled hASCs into the crushed tibial nerve of athymic nude rats. The transplanted hASCs showed a close association with PGP9.5-positive axons and myelin basic protein (MBP)-positive myelin at 8 weeks after transplantation. Quantitative analysis revealed that dhASCs transplantation resulted in significantly improved survival and myelin formation rates (a 7-fold and a 10-fold increase, respectively) as compared with uhASCs transplantation. These findings suggest that hASCs took part in supporting and myelinating regenerating axons, and thus have achieved full glial differentiation in vivo. In conclusion, hASCs can differentiate into SC-like cells that possess a potent capacity to secrete neurotrophic factors as well as to form myelin in vivo. These findings make hASCs an interesting prospect for cell-based transplantation therapy for various peripheral nerve disorders.
Neuroscience 01/2013; · 3.38 Impact Factor
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ABSTRACT: Transplantation of autologous Schwann cells (SCs) is a promising approach for treating various peripheral nerve disorders, including chronic denervation. However, given their drawbacks, such as invasive biopsy and lengthy culture in vitro, alternative cell sources would be needed. Adipose-derived stem cells (ASCs) are a candidate, and in this study rat ASCs transdifferentiated into a SC phenotype (dASC) cocultured with dorsal root ganglion neurons were shown to associate with neurites and to express myelin basic protein (MBP)-positive myelin protein. Furthermore, dASCs transplanted into a chronically denervated rat common peroneal nerve survived for at least for 10 weeks, maintaining their differentiated state. Immunohistochemical analysis revealed that transplanted dASCs associated with regenerating axons, forming MBP-/protein zero-positive myelin sheaths. The cell survival and myelin expression assessed by double labelling with S100 and glial fibrillary acidic protein were similar between the dASC- and SC-transplanted nerves. Importantly, transplantation of dASCs resulted in dramatically improved motor functional recovery and nerve regeneration, with a level comparable to, or even superior to, transplantation of SCs. In conclusion, dASCs are capable of myelinating axons in vivo and enhancing functional outcome after chronic denervation.
Journal of Neuroscience Research 03/2012; 90(7):1392-402. · 2.74 Impact Factor
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ABSTRACT: Activation of the Small GTP-binding protein Rho following the nerve injury contributes to the lack of regeneration in the peripheral nervous system. By elucidating the mechanisms leading to Rho activation, a nonsteroidal anti-inflammatory drug ibuprofen has been identified as a potent inhibitor of Rho activity. In this study we tested the hypothesis, that inhibiting Rho activity by ibuprofen will enhance posttraumatic regeneration after peripheral nerve injury.
In adult female Wistar rats we introduced an experimental injury by excising a 5 mm piece of the tibial nerve and returning it to the injury site as an interpositional graft. The animals then received ibuprofen or phosphate buffered saline through an osmotic pump for a period of 3 weeks. Following the injury we recorded tibial functional index (TFI) on a weekly basis. After 3 months we measured nerve conduction velocity and peak amplitude of action potential (PAAP). Also, the histomorphometric analysis was carried out in the zone distal to the injury site.
We found that the animals receiving ibuprofen recovered the tibial nerve function more rapidly, with the TFI being significantly different 8, 9, 11 and 12 weeks after the injury. We also detected the values of the PAAP, the area of axons and the area of myelin to be significantly greater in the experimental group.
Our results show that ibuprofen significantly enhanced regeneration after tibial nerve axotomy and repair in rats. This study is expected to set a stage for testing the ibuprofen in the human patients.
Journal of Plastic Reconstructive & Aesthetic Surgery 08/2011; 64(12):1641-6. · 1.49 Impact Factor
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Journal of Plastic Reconstructive & Aesthetic Surgery 06/2011; 64(11):1546-8. · 1.49 Impact Factor
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ABSTRACT: The Rho family of small GTPases is responsible for various processes involving actin cytoskeleton in eukaryotic cells, including neurite outgrowth. Several substances found at the peripheral nerve injury site were shown to activate one member of this family, Rho. The activation of Rho leads to neurite outgrowth inhibition and the development of posttraumatic neuropathic pain. The authors used the clinically tested Rho-associated kinase inhibitor fasudil hydrochloride to enhance the functional recovery of the peripheral nerve in the rat.
In the peroneal nerve interpositional graft model, the authors administered fasudil (experimental groups) or saline (control groups) (1) intraperitoneally and (2) directly into the graft by microinjection (n = 6 animals per experimental condition). Neural recovery was assessed during postoperative follow-up lasting 80 days by peroneal functional index, electrophysiologic, and histomorphometric analyses.
The peroneal functional index returned to values not significantly different from preoperative values on days 55 (fasudil injected into the graft) and 60 (fasudil injected intraperitoneally) in the experimental groups. In the control groups, this took 70 (saline injected intraperitoneally) and 75 days (saline injected into the graft). These results are supported by electrophysiologic and histomorphologic assessments.
The authors determined that fasudil hydrochloride was capable of accelerating the functional regeneration after peripheral nerve axotomy, which is consistent with the results of reports about Rho cascade disruption in the central nervous system. Because fasudil hydrochloride is a clinically tested drug, it could be used to enhance neural regeneration in human patients as well.
Plastic and reconstructive surgery 03/2007; 119(2):526-35. · 2.74 Impact Factor
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ABSTRACT: The development of calcium phosphate in cement paste form has made its application simplified and easy. In this study, the authors used an alpha-tricalcium phosphate/dicalcium phosphate dibasic/tetracalcium phosphate monoxide/hydroxyapatite injectable calcium phosphate cement paste to evaluate its potential use in orbital volume augmentation.
Five New Zealand white rabbits were used in this study. In each rabbit, the right orbit was directly implanted with calcium phosphate cement in its injectable paste form, and a prehardened form was placed in the left orbit. The orbital roof was approached through a subciliary skin incision and the implant was placed posterior to the globe of the eyeball to push it outward. Measurement of proptosis and intraocular pressure was monitored before and after implantation. The animals were killed after 3 months, and orbit bone-implant samples were taken for histology and microradiography.
In both groups, proptosis was induced, 4.2 +/- 0.27 mm in the prehardened group and 3.8 +/- 0.22 mm in the injectable group. These values taken 1 week postimplantation were unchanged until the end of the experiment and were maintained without significant intraocular pressure changes. The implants were well tolerated, and no sign of infection, extrusion, or migration was noted. Histologic analysis showed good biocompatibility and osteoconductivity, and microradiography has confirmed a well-set cement with direct bone union to it.
These findings therefore indicate that calcium phosphate cement implant, when used as an injectable paste or in its prehardened form, can be a safe, effective material for orbital volume augmentation.
Plastic and reconstructive surgery 05/2006; 117(4):1186-93. · 2.74 Impact Factor
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ABSTRACT: Recent studies have provided evidence that p21Cip1/WAF1 has not only cell cycle-associated activities but also other biological activities like neurite elongation. To investigate the role of p21Cip1/WAF1 in the in vivo axonal regeneration in the peripheral nervous system, we developed a p21Cip1/WAF1 knockout (KO) mice sciatic nerve injury model. We performed quantitative assessments of the functional, histological, and electrophysiological recoveries after sciatic nerve injury in p21Cip1/WAF1 KO mice and compared the results with those of the wild-type mice. p21Cip1/WAF1 KO mice showed a significant delay of the motor functional recovery between 21 and 42 days after sciatic nerve injury. The values of motor conduction velocity in p21Cip1/WAF1 KO mice were significantly lower than those in the wild-type mice on postoperative day 28. The mean percent neural tissue and the mean nerve axon width of p21Cip1/WAF1 KO mice were significantly less than those of the wild-type mice, which was caused by hyperphosphorylation of neurofilaments. Therefore, p21Cip1/WAF1 was considered to be involved in radial axon growth and to be essential for the motor functional recovery following peripheral nervous system injury.
Brain Research 05/2006; 1081(1):44-52. · 2.73 Impact Factor
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ABSTRACT: The authors describe their method of helix/antihelix creation together with their algorithm of mild conchal type microtia treatment. In mild cases of conchal type microtia, they do not use a platform-based framework but fabricate the helix and the antihelix separately from costal cartilage and anchor them firmly into the corrected remnant concha. A framework created in this way is sufficiently supportive for the new ear, has good aesthetic features, and is fast and easy to fabricate. Moreover, because the procedure does not require a large amount of cartilage, it also decreases the occurrence of donor-site complications. The authors present a group of 45 patients with a total of 47 reconstructed ears and follow-up periods of from 6 months to 6 years.
Journal of Craniofacial Surgery 12/2005; 16(6):1115-20. · 0.82 Impact Factor
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ABSTRACT: Axons of the adult central nervous system have very limited ability to regenerate after injury. This inability may be, at least partly, attributable to myelin-derived proteins, such as myelin-associated glycoprotein, Nogo and oligodendrocyte myelin glycoprotein. Recent evidence suggests that these proteins inhibit neurite outgrowth by activation of Rho through the neurotrophin receptor p75(NTR)/Nogo receptor complex. Despite rapidly growing knowledge on these signals at the molecular level, it remained to be determined whether Rho is activated after injury to the central nervous system. To assess this question, we establish a new method to visualize endogenous Rho activity in situ. After treatment of cerebellar granular neurons with the Nogo peptide in vitro, Rho is spatially activated and colocalizes with p75(NTR). Following spinal cord injury in vivo, massive activation of Rho is observed in the injured neurites. Spatial regulation of Rho activity may be necessary for axonal regulation by the inhibitory cues.
EMBO Reports 05/2004; 5(4):412-7. · 7.36 Impact Factor
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ABSTRACT: Complex processes following peripheral nerve injury integrate a number of various external cues and their intracellular responses resulting in the cytoskeletal remodeling. One of these cues, Slit protein, plays an important role in neuronal migration and axonal guidance through the interaction with Roundabout (Robo) receptor. It was reported that the signal from Robo is transmitted to a specific family of GTPase-activating proteins (GAPs) named Slit-Robo GAPs. The Slit-Robo GAPs (srGAPs) further transmit the signal to the actin cytoskeleton controlling Rho GTPases and thus provide a direct link between Slit-Robo signaling and actin cytoskeleton. We examined the effects of facial nerve transection on srGAP2 mRNA expression in the facial nerve nuclei by in situ hybridization. SrGAP2 mRNA was initially expressed, and its expression increased from 3 to 28 days after transection, with the peak at the seventh day after axotomy. The upregulation was found mostly in the neuronal cells and only to a small extent in the glial cells. Our results suggest that srGAP2, as a part of Slit-Robo pathway, plays an important role in the axonal regeneration after axotomy.
Molecular Brain Research 05/2004; 123(1-2):76-80. · 2.00 Impact Factor
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ABSTRACT: The mature peripheral nervous system has the ability to survive and to regenerate its axons following axonal injury. After nerve injury, the distal axonal and myelin segment undergoes dissolution and absorption by the surrounding cellular environment, a process called Wallerian degeneration. Using cDNA microarrays, we isolated FLRT3 as one of the up-regulated genes expressed in the distal segment of the sciatic nerve 7 days after transection relative to those of the intact sciatic nerve. FLRT3 is a putative type I transmembrane protein containing 10 leucine-rich repeats, a fibronectin type III domain, and an intracellular tail. The neurons plated on CHO cells expressing FLRT3 extended significantly longer neurites than those plated on wild-type CHO cells, demonstrating that FLRT3 promotes neurite outgrowth. FLRT3 mRNA was especially abundant in the basal ganglia, the granular layer of cerebellum, and the hippocampus, except the CA1 region in the adult rat brain. Thus, FLRT3 may contribute to regeneration following axonal injury.
Biochemical and Biophysical Research Communications 02/2004; 313(4):1086-91. · 2.48 Impact Factor
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ABSTRACT: FERM domain including Rho GEF (FIR) belongs to Dbl family of guanine nucleotide exchange factors and specifically activates biochemical pathways specific for Rac1. FIR was shown to regulate neurite remodeling of the embryonic neurons. Here we report a distribution of FIR mRNA in adult rat brain using in situ hybridization. The expression was found all throughout the brain with the most intensive signals in hippocampus, piriform cortex, red nucleus and nuclei of cranial nerves. The signal was predominantly localized in the neuronal cells.
Molecular Brain Research 07/2003; 114(2):163-7. · 2.00 Impact Factor
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Annals of Plastic Surgery 05/2002; 48(4):448-9. · 1.32 Impact Factor
