Review
Copyright ©The Author(s) 2015.
World J Stem Cells. Jan 26, 2015; 7(1): 11-26
Published online Jan 26, 2015. doi: 10.4252/wjsc.v7.i1.11
Table 1 Summary of current evidence assessing the efficacy of different types of stem cell on peripheral nerve regeneration
Stem cell sourceAuthorExperimental modelStemcell Diff.ScaffoldDelivery systemOutcome
EmbryonicCui et al[71]Rat sciatic transection (10 mm gap)DCulture mediumEpineurium natural conduitCell survival and differentiation into SCs after 3-mo; superior regeneration of myelinated axons in comparison to culture media alone
Lee et al[75]Mouse sciatic transection (2 mm gap)UMatrigelDirect injection of microspheresESC-derived MSC sphere-treated nerves recovered significantly greater CMAP, SFI and histological parameters than ESC-MSC single cell suspension
Kubo et al[77]Mouse tibialDPBSDirect injection into gastrocnemius muscles following nerve transection and repairCo-culture identified formation of new NMJs; muscle transplanted with stem cells experienced less atrophy 7 and 21-d post injury; cells transplanted after 2-wk were unable to provide any protective effect; motor recovery following repair superior in those muscles receiving stem cells
Craff et al[76]Rat sciatic + gastrocnemius muscleDPBSDirect injection into gastrocnemius muscles following nerve transectionMuscles injected with stem cells retained muscle weight preservation and myocyte cross sectional area in comparison to control muscle after 7-d post injury. New NMJs observed. Benefits lost after 21 d
NeuralFu et al[15]Rat sciatic transection (15 mm gap; gene transfection)U (gene therapy)Culture medium (cells seeded directly onto conduit wall)Poly(D,L-Lactide) conduitEnhanced expression of BDGF and GDNF in transfected cells; conduits with transfected cells led to larger myelinated axons and improved functional and electrophysiological outcome
Zhang et al[62]Rabbit facial nerve transection (5 mm gap)UCollagen mediumHA-collagen composite conduitConduits with NSCs and NT-3 experienced superior outcomes in comparison to NSC alone; results equivalent to normal nerves after 12-wk
Murakami et al[86]Rat sciatic transection (15 mm gap)UCollagen gelSilicone conduitNSCs differentiated into astrocytes, oligodendrocytes and schwann cell-like cells; dNCSs implanted into 15 mm defects; Improved axon number, diameter and myelination compared with controls; labeled cells present after 10-wk; expressed markers of SC phenotype
Guo et al[87]Rabbit facial nerve transection (10 mm gap)UCollagen spongeChitosan conduitElectrophysiological and histological outcomes and immunohistochemistry superior in chitosan conduits seeded with NSCs and NGF in comparison to conduit+NGF alone. Results comparable to standard autograft
Liard et al[88]Pig nervis cruralis transection (30 mm gap)UNeurosphere in culture mediumAutologous vein graftGrafts containing NSCs recovered superior EMG recording and immunohistochemistry profiles in comparison to empty conduits; NSCs identifiable after 240 d follow-up.
Johnson et al[89]Rat sciatic crush, transection, (10 mm gap)U (C17.2)Culture mediumDirect injection12/45 rodents developed neuroblastomas
Bone marrowZhao et al[160]Rat sciatic transection (15 mm gap)UFibrin glueANASurvival of BMSCs within fibrin glue; growth factor secretion preserved (NGF, BDNF); equivalent results when cells injected directly into nerve compared with around nerve
Hu et al[165]Monkey median transection (50 mm gap)UCulture mediumChitosan conduit with longitudinally aligned PGLA fibersFunctional and electrophysiological recovery and FG retrograde tracing after 1-year with BMSC-laden conduits equivalent to autograft and superior to empty conduits
Dezawa et al[19]Rat sciatic transection (15 mm gap)U + DMatrigelMatrigel graftSuccessful differentiation into SC phenotype; Axon number and elongation superior with dBMSCs
Jia et al[32]Rat sciatic transection (10 mm gap)UGelatinAcellular xenograftNeurotrophic factor expression elevated in BMSC xenografts; regeneration and functional recovery significantly better than empty xenografts and equivalent to autograft
Mohammadi et al[34]Rat sciatic transection (10 mm gap)UCulture mediumVein graftVeins filled with uBMSCs had significantly improved functional, histological and immunohistochemical outcomes compared with veins filled with PBS
Nijhuis et al[36]Rat sciatic transection (15 mm gap)UCulture mediumVein graft +/- muscleBMSC identifiable after 6 and 12-wk follow-up; vein graft + muscle + BMSCs outperformed vein graft+muscle but inferior to autograft
Salomone et al[39]Rat facial nerve transection (3 mm gap)U + DMatrigelSilicone conduitHistological outcomes superior in conduits containing uBMSCs and dBMSCs compared to empty and matrigel containing conduits; functional outcomes superior using uBMSCs
Wang et al[41]Rat sciatic transection (15 mm gap)UCulture mediumDirect injection into ANABMSC produced NGF and BDNF; CSPGs reduced in grafts treated with ChABC Allograft containing BMSCs and ChABC resulted in superior functional, electrophysiological and histological outcome compared with BMSC alone
Adiposedi Summa et al[28]Rat sciatic transection (10 mm gap)DCulture mediumFibrin glue conduitReduced muscle atrophy in autograft, dADSC and dBMSC groups in comparison to empty conduits; dADSCs recovered greatest axon and fiber diameter, evoked potentials and regeneration of motorneurons; results comparable to autograft
Tomita et al[21]Rat common peroneal nerve transection (no gap)DCulture mediumDirect injection into distal nervedADSCs survived for at least 10 wk in vivo; dADSCs associated with axons and participated in re-myelination; dADSCs resulted in regeneration superior to cultured SCs
Zhang et al[31]Rat sciatic transection (10 mm gap)DCollagen gelXenogeneic acellular graftdADSCs formed columns resembling bands of Büngner and expressed NGF, BDNF and GDNF; axon regeneration, retrograde labeling and electrophysiology were similar between dADSCs and SC supplemented grafts, superior to empty grafts but inferior to standard autograft
Mohammadi et al[33]Rat sciatic transection (10 mm gap)UCulture mediumVein graftNo difference in functional, morphometric or immunohistochemistry between ADSCs and BMSCs
Erba et al[45]Rat sciatic transection (10 mm gap)UFibrinPHB conduitLack of sufficient quantities of viable cells 14-d after transplantation; conclusion that regenerative effect due to initial growth factor boost or paracrine effect on resident cells
Sun et al[51]Rat facial transection (8 mm gap)DMatrigelDecellularized allogeneic arterydADSCs persisted at repair site and integrated with regenerated tissue; conduits containing dADSCs achieved results comparable to those of SC-containing conduits and superior to matrigel-containing conduits alone; results inferior to autograft
FetalPan et al[106]Rat sciatic crushUFibrin glueDirect injection at siteHigh expression of BDNF, CNTF, NGF and NT-3 found in AFMSCs; motor function, CMAP and conduction velocity improved in those nerves augmented with AFMSCs; high levels of S-100 and GFAP and reduced fibrosis found at repair site
Pan et al[111]Rat sciatic crushUFibrin glueDirect injection at siteHBO therapy reduced production of inflammatory cytokines and macrophage chemokines following crush injury; when administered with AFMSCs, HBO reduced apoptosis of AFMSCs in comparison to AFMSCs alone; myelination and motor recovery superior in HBO + AFMSC group
Pan et al[110]Rat sciatic crushUFibrin glueDirect injection at siteAnti-apoptotic, anti-inflammatory agent G-CSF, when administered with AFMSCs, reduced crush-induced inflammation, and apoptosis in comparison to AFMSCs alone; myelination and motor function superior with AFMSCs + G-CSF in comparison to AFMSCs alone
Matsuse et al[109]Rat sciatic nerve transection (8 mm gap)U + DMatrigel“Transpermeable” tubeDifferentiated UC-MSCs regenerated greater number of myelinated axons and thicker nerve fibers compared with undifferentiated UC-MSCs; number of labeled cells greater in dUC-MSC nerves; results comparable to SC group
Cheng et al[113]Rat sciatic crushUMatrigelDirect injection at siteAFMSCs successfully transfected; high expression of GDNF detected for 4 wk before subsiding; GDNF-modified AFMSCs recovered greatest SFI, conduction velocity, CMAP and muscle weight in comparison to AFMSCs alone
Gärtner et al[108]Rat sciatic crushDCulture mediumCells seeded onto PLC wrapWraps seeded with UC-MSCs resulted in superior increased myelin thickness, motor and sensory function in comparison to unseeded wraps
SkinMcKenzie et al[120]Mouse sciatic crushD/UCulture mediumDirect injection at siteSKPs successfully induced into SKP-SCs; SKP and SKP-SCs associated with and myelinated axons
Marchesi et al[123]Rat sciatic transection (16 mm gap)DPBS(1) Synthetic co-polymer L-lactide and trimethylene carbonate; and (2) collagen conduitSFI and CMAPs were significantly better in conduits filled with SDSCs; number of regenerated myelinated axons significantly greater in SDSC conduits; no significant difference in neurotrophic factor expression
Walsh et al[124]Rat sciatic transection (12 mm gap)DCulture mediumDirect injection into acellular freeze-thawed nerve graftSKP-SCs maintained differentiation up to 8-wk; outcomes significantly improved in comparison to cell free grafts and comparable to cultured SCs; neurotrophic factor release greater in SKP-SCs
Walsh et al[121]Rat CP/tibial (Immediate vs chronic repair; no gap)DCulture mediumDirect injection into distal nerveMuscle weight and CMAPs superior in SKP-SC group in comparison to media injected controls; significantly higher counts of axon regeneration in SKP-SC group equivalent to immediate suture group
Walsh et al[22]Rat sciatic transection [acute vs chronic vs ANA (12 mm gap)]U/DCulture mediumDirect injection into nerve ends and ANASKP-SCs maintained in vivo viability and differentiation better than uSKP; viability poorest in normal nerve, best in acutely injured nerve; SKP-SCs remain differentiated over time and myelinate axons; neuregulin able to prevent apoptosis following transplantation
Khuong et al[122]Rat sciatic and tibial (12 mm gap)DCulture mediumDirect injection into ANASKP-SCs containing allografts resulted in superior functional and histological outcomes in both acute and delayed injury models compared with SCs and media controls
Hair follicleAmoh et al[135]Mouse sciatic and tibial transection (no gap)UCulture mediumDirect injection at siteHFSC transplanted nerves recovered significantly greater function compared with untreated nerves; GFP-labeled cells differentiated into GFAP positive schwann cells and were involved with myelination
Amoh et al[133]Mouse sciatic crushUCulture mediumDirect injection at siteHFSCs transplanted around crushed nerve differentiated into SC-like cells and participated in myelination; gastrocnemius muscle contraction significantly greater compared with untreated crushed nerves
Amoh et al[134]Mouse sciatic transection (2 mm gap)UCulture mediumDirect injection at siteHFSCs differentiated into GFAP expressing SCs and were able to myelinate axons; gastrocnemius muscle contraction significantly greater compared with untreated nerves
Lin et al[136]Rat sciatic transection (40 mm gap)DPBSDirect injection into acellular xenograftDifferentiation into neurons and SCs maintained for 52-wk; number of regenerated axons, myelin thickness and ratio of myelinated axons to total nerve count significantly higher in dHFSCs compared with acellular grafts; conduction velocity slower in dHFSC nerves
Induced pluripotent stem cellIkeda et al[146]Mouse sciatic nerve (5 mm gap)DMicrosphere seeded into conduitMixed PLA/PCL conduit +/- iPSC microspheres +/- bFGFRegeneration was accelerated by combination of iPSCs + bFGF within conduits in comparison to iPSCs and bFGF alone; outcomes remained inferior to autograft controls; empty conduits performed least well
Uemura et al[148]Mouse sciatic nerve (5 mm gap)DMicrosphere seeded into conduitMixed PLA/PCL conduit +/- iPSC microspheresMotor and sensory recovery was superior in iPSC group at 4, 8 and 12 wk in comparison to empty conduits. Axonal regeneration superior in iPSC group. Conduit structurally stable after 12 wk
Wang et al[149]Rat sciatic nerve (12 mm gap)DMatrigelPLCL/PPG/sodium acetate copolymer electrospun nanofiber conduitConduits filled with either (1) matrigel; (2) matrigel + NCSCs differentiated from ESCs; and (3) matrigel + NCSCs differentiated from iPSCs; NCSC differentiated into SCs and integrated into myelin sheaths; electrophysiology and histology showed equivalent regeneration in all NCSC containing conduits; no teratoma formation observed after 1-yr