Nerve Stem Cells Research Articles

Flavonoids in Combination with Stem Cells for the Treatment of Neurological Disorders.

Neurological disorders are the leading cause of disability and the world's second leading cause of death. Despite the availability of significant knowledge to reduce the burden of some neurological disorders, various studies are exploring more effective treatment options. While the human body can repair and regenerate damaged tissue through stem cell recruitment, nerve regeneration in case of injury is minimal due to the restriction on the location of nerve stem cells. Recently, different types of stem cells extracted from various tissues have been used in combination with natural stimuli to treat neurologic disorders in neuronal tissue engineering. Flavonoids are polyphenolic compounds that can induce the differentiation of stem cells into neurons and stimulate stem cell proliferation, migration, and survival. They can also increase the secretion of nutritional factors from stem cells. In addition to the effects that flavonoids can have on stem cells, they can also have beneficial therapeutic effects on the nervous system alone. Therefore, the simultaneous use of these compounds and stem cells can multiply the therapeutic effect. In this review, we first introduce flavonoid compounds and provide background information on stem cells. We then compile available reports on the effects of flavonoids on stem cells for the treatment of neurological disorders.

Cytomegalovirus infection of brain tumors and CMV immunotherapy

Objective. The article presents the literature of the last ten years and the results of our own research on the importance of cytomegalovirus (CMV) in the development of brain tumors, especially glioblastoma and medulloblastoma. Two alternative views are discussed - the pros and cons of the role of the virus in the induction and stimulation of tumor growth.Materials and methods. 256 samples of biotic material of tissues of various brain tumors were studied. Among them are histologically diagnosed: in 123 cases glial tumors of various grade of malignancy, in 51 cases meningiomas, in 25 cases medulloblastomas, in 16 cases oligodendroastrocytomas of the second grade of malignancy, in 14 cases metastatic tumors. Tumor fragments were obtained from biopsy material 1.5-2.0 hours after surgical removal. To detect the presence of CMV in the tumor tissue real-time polymerase chain reaction (PCR) using "DNA sorb A and B" kits was performed, the company "Amplisens" (Russia), according to the manufacturer’s instructions and BioRal device (USA) with standard DNA detection kits of CMV "DNA Technology" (Russia). Cytological imprints on slides were also made from tumor tissue fragments, which were examined by indirect immunofluorescence method with monoclonal antibodies to CMV pP-65 protein using the "MonoScan CMV" kit.Results. The frequency of detection of CMV antigen or its DNA in brain tissue depends on the research method - the immunofluorescence method detects pP-65 antigen by monoclonal antibodies 2-2.5 times more often than the PCR method of CMV in tumor tissue. In the tissue of different histogenesis of brain tumors both the pP-65 antigen and CMV DNA are detected with different frequencies. CMV was most often detected in tumors of glial origin and medulloblastomas. No CMV DNA was detected in the peripheral blood of patients with brain tumors at the time of admission for examination and surgical treatment, indicating an earlier contamination of the tumor focus with this virus. Data on the mechanisms of CMV induction and stimulation of tumor growth by activating cell proliferation, including nerve stem cells, are presented. Works using specific antiviral therapy and CMV specific cell immunotherapy in the treatment of gliomas have been analyzed in detail.Conclusions. The paper concludes on the important clinical and prognostic value of determining CMV infection in brain tumors and indicates the need for CMV viral and cellular immunotherapy in the combined treatment of malignant brain tumors.

Вплив нейротрофічних факторів на популяцію серотонінергічних нейронів n.raphe в умовах культивування

Актуальність. Молекулярні механізми спеціалізації серотонінергічних нейронів зі стовбурових і прогеніторних нервових клітин вивчені далеко не повністю. Мета дослідження — визначення найбільш ефективних нейроіндукторів, що підтримують життєздатність та функціональну активність серотонінергічних нейронів та їх детермінованих попередників. Як критерії оцінки були обрані: експресія відповідних генів, загальний вміст серотоніну та чисельність серотонінергічних нейронів, візуалізованих за допомогою гістохімічної реакції. Матеріали та методи. Робота була виконана на суспензійній культурі клітин зони n.raphe з використанням гістохімічних методів, імуноферментного аналізу та полімеразної ланцюгової реакції. Результати. Установлено, що BDNF та NGF стимулюють збільшення чисельності серотонінергічних нейронів у дисоційованій культурі в 1,6 та 2 рази порівняно з контрольними зразками. Додавання в культуральне середовище BDNF та ретиноєвої кислоти призводить до зростання вмісту серотоніну в культуральному матеріалі. Експресія гена Nkx 2.2, що є маркером мітотично-активних попередників серотонінергічних нейронів, підтримується за наявності BDNF і збільшується під впливом EGF та FGFb. Експресія гена Pet1, що свідчить про наявність детермінованих прогеніторів серотонінергічних нейронів, підтримується всіма досліджуваними факторами, за виключенням екзогенного серотоніну. Експресія гена Tph1, маркера початку синтезу серотоніну, спостерігається під впливом FGFb, EGF та NGF. Висновки. Таким чином, наші дані показали, що вищевказані нейроіндуктори впливають на різні фази серотонінгенезу і можуть бути використані для його регуляції.

Exosomes Derived from Nerve Stem Cells Loaded with FTY720 Promote the Recovery after Spinal Cord Injury in Rats by PTEN/AKT Signal Pathway.

Background Spinal cord injury (SCI) remains a challenge owing to limited therapies. The exosome of neural stem cells (NSCs-Exos) and FTY720 transplantation could improve SCI effectively. However, the effect and mechanism of NSCs-Exos combined with FTY720 (FTY720-NSCs-Exos) transplantation in the treatment of SCI are not fully understood. Methods Sprague Dawley rats (8-week-old) were used to establish the SCI model, followed by the treatment of NSCs-Exos, FTY720, and FTY720-NSCs-Exos. The effect of FTY720, NSCs-Exos, and FTY720-NSCs-Exos combination treatment on hindlimb function, pathological changes, apoptosis activity, and the expression of spinal edema-related proteins and apoptosis-related proteins in SCI models were investigated by BBB scoring, HE staining, TUNEL staining and immunohistochemistry, and Western blotting. Meanwhile, the effect of these treatments on spinal cord microvascular endothelial cells (SCMECs) was detected under hypoxic circumstance. Results Our results found that FTY720-NSCs-Exos could alleviate pathological alterations and ameliorate the hindlimb function and oxygen insufficiency in model mice after SCI. In addition, exosomes could ameliorate the morphology of neurons, reduce inflammatory infiltration and edema, decrease the expression of Bax and AQP-4, upregulate the expression of claudin-5 and Bcl-2, and inhibit cell apoptosis. At the same time, in vitro experiments showed that FTY720-NSCs-Exos could protect the barrier of SCMECs under hypoxic circumstance, and the mechanism is related to PTEN/AKT pathway. Conclusion FTY720-NSCs-Exos therapy displayed a positive therapeutic effect on SCI by regulating PTEN/AKT pathway and offered a new therapy for SCI.

Edaravone Improves the Post-traumatic Brain Injury Dysfunction in Learning and Memory by Modulating Nrf2/ARE Signal Pathway

OBJECTIVES:To investigate the molecular mechanism of edaravone (EDA) in improving the post-traumatic brain injury (TBI) dysfunction in learning and memory.METHODS:In vitro and in vivo TBI models were established using hydrogen peroxide (H2O2) treatment for hippocampal nerve stem cells (NSCs) and surgery for rats, followed by EDA treatment. WST 1 measurement, methylthiazol tetrazolium assay, and flow cytometry were performed to determine the activity, proliferation, and apoptosis of NSCs, and malondialdehyde (MDA), lactic dehydrogenase (LDH), and reactive oxygen species (ROS) detection kits were used to analyze the oxides in NSCs.RESULTS:Following EDA pretreatment, NSCs presented with promising resistance to H2O2-induced oxidative stress, whereas NSCs manifested significant increases in activity and proliferation and a decrease in apoptosis. Meanwhile, for NSCs, EDA pretreatment reduced the levels of MDA, LDH, and ROS, with a significant upregulation of Nrf2/antioxidant response element (ARE) signaling pathway, whereas for EDA-treated TBI rats, a significant reduction was observed in the trauma area and injury to the hippocampus, with improvement in memory and learning performance and upregulation of Nrf2/ARE signaling pathway.CONCLUSIONS:EDA, by regulating the activity of Nrf2/ARE signal pathway, can improve the TBI-induced injury to NSCs and learning and memory dysfunction in rats.

Nerve Regeneration and Stem Cells

Nerve traumas are very common in the world and complete disruption of the nerve trunks without treatment, would result in partial regeneration and repair, partial or total loss of function [1,2]. .

Nerve Stem Cell Differentiation by a One-step Cold Atmospheric Plasma Treatment <em>In Vitro</em>

As the development of physical plasma technology, cold atmospheric plasmas (CAPs) have been widely investigated in decontamination, cancer treatment, wound healing, root canal treatment, etc., forming a new research field named plasma medicine. Being a mixture of electrical, chemical, and biological reactive species, CAPs have shown their abilities to enhance nerve stem cells differentiation both in vitro and in vivo and are becoming a promising way for neurological disease treatment in the future. The much more exciting news is that using CAPs may realize one-step, and safely directed, differentiation of neural stem cells (NSCs) for tissue transportation. We demonstrate here the detailed experimental protocol of using a self-made CAP jet device to enhance NSC differentiation in C17.2-NSCs and primary rat neural stem cells, as well as observing the cell fate by inverted and fluorescence microscopy. With the help of immunofluorescence staining technology, we found both the NSCs showed an accelerated differential rate than the untreated group, and ~75% of the NSCs selectively differentiated into neurons, which are mainly mature, cholinergic, and motor neurons.

Devising micro/nano-architectures in multi-channel nerve conduits towards a pro-regenerative matrix for the repair of spinal cord injury

Multi-channel nerve conduits have shown significant advantages in guidance of axonal growth and functional restoration after spinal cord injury (SCI). It was realized that the micro/nano-architectures of these implanted conduits can effectively tune the lesion-induced biological responses, including inflammation and scar formation. In this work, two PLLA multi-channel conduits were fabricated with ladder-like porous channel wall (labelled as LNCs) and nano-fibrous channel wall (labelled as NNCs), respectively, and transferred into complete spinal cord transected injury model in rats. The implantation of such two scaffolds significantly alleviated the infiltration of macrophages/microglia and accumulation of astrocyte and collagen scar, especially in the NNCs group. Meanwhile, recruitment of endogenous stem cells and axonal growth was observed in both of the multi-channel conduits. Compared to the LNCs, the extracellular matrix (ECM) – mimicry nanostructures in the NNCs promoted directional nerve fiber growth within the channels. Moreover, a relatively denser nano-architecture in the channel wall confined the nerve fiber extension within the channels. These results from in vivo evaluations suggested that the NNCs implants possess a great potential in future application for SCI treatment and nerve regeneration. Statements of SignificanceThe implantation of biocompatible and degradable polymeric scaffolds holds great potential in clinical treatment and tissue regeneration after spinal cord injury (SCI). In this work, the ladder-like nerve conduits (LNCs) and nano-fibrous nerve conduits (NNCs) were fabricated and implanted into completely spinal cord transected rats, respectively. In vivo characteristics showed significant reduction in post-injury inflammation and scar formation, with elevated nerve stem cells (NSCs) recruitment and nerve fiber growth, hence both conduits resulted in significant functional restoration after implantation. Remarkably, we noticed that not only the multi-channels in the conduits can guide nerve fiber regeneration, their micro-/nano-structured walls also played a critical role in modulating the post-implantation biological responses.

Progress of Experimental Researches on Mechanisms of Acupuncture Underlying Improvement of Ischemic Cerebral Vascular Disease by Regulating Different Intracellular Signaling Pathways

China is in the "high death zone" of the world cerebrovascular disease (CVD) map. The prevention and treatment of ischemic CVD (ICVD) have become the top priority in clinical practice. It has been demonstrated that acupuncture therapy has a positive role in bettering clinical symptoms of ICVD patients. Findings of recent experimental studies displayed that electroacupuncture (EA) intervention is effective in reducing the cerebral infarcted volume and cellular injury, promoting proliferation, migration and differentiation of nerve stem cells, facilitating the regeneration of nerve tissue, bettering dysneuria and limb locomotor ability, etc. in ICVD rats, which are closely associated with its effects in regulating different intracellular signaling pathways. In the present study, we review the progress of recent experimental studies on the underlying mechanisms of EA in improving ICVD from six major signaling pathways including Notch, mitogen-activated protein kinases (MAPK)/ extracellular signal regulated protein kinases (ERK), phosphatidy linositol-3-kinase (PI 3 K)/ protein kinase B (Akt), Janus kinase-signal transducer and activator of transcription (JAK-STAT), erythropoietin-producing hepatocyte receptor (Eph)/Ephrin, nuclear factor of kappa B (NF-κB) and their compositions, which may provide new therapeutic targets for acupuncture treatment of ICVD. More attention should be paid to the comparison of the efficacy of acupuncture of different acupoint combinations (traditional acupoint formulas) in relieving ICVD.

Nano-fibrous and ladder-like multi-channel nerve conduits: Degradation and modification by gelatin

We recently fabricated multi-channel PLLA nerve conduits (NCs, conduits diameter: ~3mm, channels diameter: ~200μm) with nano-fibrous microstructure (NNCs) and ladder-like microstructure (LNCs), and found the nanofibers in the NNCs promote differentiation of nerve stem cells (NSCs) into neurons. In the present study, we evaluated the degradation profile of NNCs and LNCs, and observed that NNCs degraded too fast to implant. To delay the degradation and retain the nano-scale effect of NNCs, we used gelatin to wrap (2% w/v gelatin) or embed (8% w/v gelatin) NNCs and LNCs via vacuum infusion and chemical cross-linking with genipin. NNCs-wrapped maintained their original nano-fibrous microstructure, but NNCs-embedded presented a porous morphology without nanofibers appearing. Incorporation of gelatin did not change their compressive moduli, but increased the creep recovery ratios of LNCs and NNCs. In vitro degradation revealed that integrity was maintained and the mass loss was <5% for NNCs-wrapped after 10weeks, in comparison with 15% mass loss and collapsed structure of the pure NNCs after 4weeks. Meanwhile, there were no obvious changes in the degradation of LNCs with modification. Nerve stem cells (NSCs) were then seeded onto the six NCs represented as: NNCs, NNCs-wrapped, NNCs-embedded, LNCs, LNCs-wrapped, and LNCs-embedded. Immunocytochemistry analysis demonstrated that gelatin coating enhanced the adhesion and proliferation of NSCs, and the NNCs-wrapped scaffold promoted the differentiation proportion of NSCs into neurons from 25.8% (on pure NNCs) to 53.4% after 14days of seeding. On the other hand, only 14.3% of neurons were derived from the differentiation of the seeded NSCs on the NNCs-embedded. NNCs-wrapped would be a good choice for future studies in nerve injury repair in vivo due to its appropriate degradation rate, flexibility, and nano-scale effect.

By up-regulating μ- and δ-opioid receptors, neuron-restrictive silencer factor knockdown promotes neurological recovery after ischemia.

We investigated the effects of neuron-restrictive silencer factor (NRSF) on proliferation of endogenous nerve stem cells (NSCs) and on μ- and δ-opioid receptor (MOR/DOR) expression in rats after cerebral ischemia. Among 100 rats subjected to cerebral ischemia, 20 rats were transfected with NRSF shRNA, and the remaining 80 were randomly assigned to normal, sham, model, and negative control (NC) groups. On days 7, 14, and 28 after ischemia and reperfusion, neurological function scores were assigned and a step-down passive avoidance test was conducted. Nerve function scores, step-down reaction periods, error times and apoptosis rates, as well as levels of B-cell CLL/lymphoma 2 (Bcl-2), BCL2-associated X protein (Bax), and NRSF expression were lower in the NRSF shRNA group than in the model and NC groups. By contrast, step-down latency, numbers of bromodeoxyuridine-positive cells, MOR/DOR expression, and phosphorylation of extracellular signal regulated protein kinase (ERK) and cAMP response element binding protein (CREB) were higher in the NRSF shRNA group than in the model and NC groups. These results suggest that by up-regulating MOR/DOR expression, NRSF knockdown accelerates recovery of neurological function after cerebral ischemia, at least in part by promoting NSC proliferation and inhibiting apoptosis.

Electrospinning of poly(glycerol sebacate)-based nanofibers for nerve tissue engineering

Nerve tissue engineering (TE) requires biomimetic scaffolds providing essential chemical and topographical cues for nerve regeneration. Poly(glycerol sebacate) (PGS) is a biodegradable and elastic polymer that has gained great interest as a TE scaffolding biomaterial. However, uncured PGS is difficult to be electrospun into nanofibers. PGS would, therefore, require the addition of electrospinning agents. In this study, we modified PGS by using atom transfer radical polymerization (ATRP) to synthesize PGS-based copolymers with methyl methacrylate (MMA). The synthesized PGS-PMMA copolymer showed a molecular weight of 82kDa and a glass transition temperature of 115°C. More importantly, the PGS-PMMA could be easily electrospun into nanofiber with a fiber diameter of 167±33nm. Blending gelatin into PGS-PMMA nanofibers was found to increase its hydrophilicity and biocompatibility. Rat PC12 cells were seeded onto the PGS-PMMA/gelatin nanofibers to investigate their potential for nerve regeneration. It was found that gelatin-containing PGS-based nanofibers promoted cell proliferation. The elongated cell morphology observed on such nanofibers indicated that the scaffolds could induce the neurite outgrowth of the nerve stem cells. Overall, our study suggested that the synthesis of PGS-based copolymers might be a promising approach to enhance their processability, and therefore advancing bioscaffold engineering for various TE applications.

Development of Polyvinyl Alcohol Fibrous Biodegradable Scaffolds for Nerve Tissue Engineering Applications: In Vitro Study

In this study, polyvinyl alcohol (PVA) fibers were modified through an effective cross linking method. Adequate porosity and surface area are widely recognized as important parameters in the design of scaffolds for tissue engineering and therefore measurement of porosity is very important. Herein, porosity measurement of various surface layers of scaffold was done through a new method, and image analysis was used for this purpose. Scanning electron microscopy micrographs of nanofibrous scaffolds were converted to binary images using different thresholds and porosity of scaffold was measured in various layers. In addition, for ascertaining of cross linking of the PVA nanofibrous scaffolds, Fourier transform infrared spectroscopy analysis was employed. Also, the in vitro biodegradability of the nanofibrous scaffold was evaluated. The PVA crosslinked nanofibrous scaffold was found to exhibit the most balanced properties to meet all the required specifications for nerve tissue and was used for in vitro culture of nerve stem cells (PC12 cells). Finally, the results of the swelling behavior of the samples revealed that the cross linked PVA scaffold has a strong swelling about 450%.

Fabrication and evaluation of PLLA multichannel conduits with nanofibrous microstructure for the differentiation of NSCs in vitro.

Nerve conduits (NCs) with multiple longitudinally aligned channels, being mimicking the natural nerves anatomical structure, have been attracted more and more attentions. However, some specific structural parameters of a conduit that would be beneficial for further improvement of neural tissue regeneration were not comprehensively considered. Using a systematized device and combining low-pressure injection molding and thermal-induced phase separation, we fabricated 33-channel NCs (outer diameter 3.5 mm, channel diameter 200 μm) with different well-defined microscopic features, including NCs with a nano-fibrous microstructure (NNC), NCs with microspherical pores and nano-fibrous pore walls (MNC), and NCs with a ladder-like microstructure (LNC). The porosities of these NCs were ∼90% and were independent of the fine microstructures, whereas the pore size distributions were clearly distinct. The adsorption of bovine serum albumin for the NNC was a result of having the highest specific surface area, which was 3.5 times that of the LNC. But the mechanical strength of NNC was lower than that of two groups because of a relative high crystallinity and brittle characteristics. In vitro nerve stem cells (NSCs) incubation revealed that 14 days after seeding the NSCs, 31.32% cells were Map2 positive in the NNC group, as opposed to 15.76% in the LNC group and 23.29% in the MNC group. Addition of NGF into the culture medium, being distinctive specific surface area and a high adsorption of proteon for NNC, 81.11% of neurons derived from the differentiation of the seeded NSCs was obtained. As a result of imitating the physical structure of the basement membrane of the neural matrix, the nanofibrous structure of the NCs has facilitated the differentiation of NSCs into neurons.

Biotransformation of Ginsenoside Rb1 into Rd by the Bacterium Lysobacter panaciterrae

Triterpenoid saponins and ginsenosides, the majority of which contain the aglycons protopanaxadiol or protopanaxatriol, are important biologically active compounds of Panax ginseng C. A. Meyer. The principal ginsenoside, the content of which in ginseng root is >20% of the total saponins, is Rb1 (1), which includes -sophorose and -gentiobiose residues (6-O-Dglucopyranosyl-D-glucose) in the C-3 and C-20 positions, respectively, of 20(S)-protopanaxadiol. The minor ginsenoside Rd (2) is a close structural analog of Rb1 and has a glucose instead of -gentiobiose in the C-20 position [1]. Rd has a broader spectrum of biological activity than Rb1, for example, it increases the differentiation of nerve stem cells, protects neurons from neurotoxic substances, and inhibits proliferation of HepG2 liver cancer cells [2]. However, the content of Rd in ginseng root is 4–5 times less than that of Rb1. Therefore, biotransformation of ginsenoside Rb1 into Rd, in particular by using microorganisms, is of practical importance [3].

Coexpression of recombinant adenovirus carrying GDNF and EDNRB genes in neural stem cells in vitro

Gene therapy and nerve stem cells isolated from the developing human enteric nervous system (ENS) are significant. They may open the route for the cell therapy of Hirschsprung's disease (HD). We have constructed the recombinant adenovirus-carrying glial cell line-derived neurotrophic factor (GDNF) and endothelin receptor B (EDNRB) gene, and investigated the exosomatic coexpression in neural stem cells. The recombinant adenovirus Ad-GE coexpressing GDNF and EDNRB gene was constructed by the AdEasy system and confirmed by the reverse transcription polymerase chain reaction (RT-PCR) method. Expression of exogenous genes in neural stem cells after transfection was confirmed by the flow cytometry and real-time fluorescence quantitative PCR. Fragments of pAd Track-CMV-GE were consistent with GDNF and EDNRB. The green fluorescence of the positive cells was followed by fluorescence microscopy at 24 h after NSCs had been transfected, reaching a peak at 72 h after transfection. Flow cytometry showed that the efficiency of transfection was 15.0, 23.6, and 25.4% at 24, 48 and 72 h respectively. Real-time fluorescence quantitative PCR showed the expression levels of mRNA of GDNF and EDNRB in 48 and 72 h groups were obviously higher than that in 24 and 96 h groups. Recombinant adenovirus carrying GDNF and EDNRB genes are coexpressed in neural stem cells, which may offer the possibility of a novel approach to local combination gene therapy for Hirschsprung's disease.

Effect of Danshen aqueous extract on serum hs-CRP, IL-8, IL-10, TNF-α levels, and IL-10 mRNA, TNF-α mRNA expression levels, cerebral TGF-β1 positive expression level and its neuroprotective mechanisms in CIR rats

To observe the effects of Danshen aqueous extract (DSAE) on the cerebral tissue and nerve stem cells in cerebral ischemia reperfusion (CIR) rats. The model rats were prepared by occlusion of the middle cerebral artery for 2 h and then by reperfusion. They were randomly divided into five groups: a control group, an CIR group and three DSAE-treated groups. As compared with the sham control group, there was significant increase (P < 0.05, P < 0.01) in the serum high-sensitivity C-reactive protein (hs-CRP) and interleukin-8 (IL-8) levels, interleukin-10 (IL-10), tumor necrosis factor-alpha (TNF-α) levels, and IL-10 mRNA, TNF-α mRNA expression levels, function score, Infarct size, TUNEL + cell counts, cerebral transforming growth factor beta 1 (TGF-β1) positive expression and cerebral neuron specific enolase (NSE) levels, and decrease in fas-associated protein with death domain (FADD) and death-associated protein (Daxx) positive expression levels in the CIR group. Compared with CIR group, DSAE treatment dose-dependently significantly decreased serum hs-CRP, IL-8, IL-10, TNF-α levels, and IL-10 mRNA, TNF-α mRNA expression levels, function score, Infarct size, TUNEL + cell counts, cerebral TGF-β1 positive expression and cerebral NSE levels, and increase FADD and Daxx positive expression levels in the CIR + DSAE groups. Taken together, these results suggest that DSAE has a neuroprotective role in the CIR rats, which may be related to improvement of immunity function, proteins and genes expression.

Electrospun bio‐composite P(LLA‐CL)/collagen I/collagen III scaffolds for nerve tissue engineering

One of the biggest challenges in peripheral nerve tissue engineering is to create an artificial nerve graft that could mimic the extracellular matrix (ECM) and assist in nerve regeneration. Bio-composite nanofibrous scaffolds made from synthetic and natural polymeric blends provide suitable substrate for tissue engineering and it can be used as nerve guides eliminating the need of autologous nerve grafts. Nanotopography or orientation of the fibers within the scaffolds greatly influences the nerve cell morphology and outgrowth, and the alignment of the fibers ensures better contact guidance of the cells. In this study, poly (L-lactic acid)-co-poly(ε-caprolactone) or P(LLA-CL), collagen I and collagen III are utilized for the fabrication of nanofibers of different compositions and orientations (random and aligned) by electrospinning. The morphology, mechanical, physical, and chemical properties of the electrospun scaffolds along with their biocompatibility using C17.2 nerve stem cells are studied to identify the suitable material compositions and topography of the electrospun scaffolds required for peripheral nerve regeneration. Aligned P(LLA-CL)/collagen I/collagen III nanofibrous scaffolds with average diameter of 253 ± 102 nm were fabricated and characterized with a tensile strength of 11.59 ± 1.68 MPa. Cell proliferation studies showed 22% increase in cell proliferation on aligned P(LLA-CL)/collagen I/collagen III scaffolds compared with aligned pure P(LLA-CL) scaffolds. Results of our in vitro cell proliferation, cell-scaffold interaction, and neurofilament protein expression studies demonstrated that the electrospun aligned P(LLA-CL)/collagen I/collagen III nanofibrous scaffolds mimic more closely towards the ECM of nerve and have great potential as a substrate for accelerated regeneration of the nerve.

Human nerve stem cells in vitro

The expansion of Nest-positive nerve stem cells fraction in the culture of human fetal brain was investigated in this work. Our results demonstrated the valuable increase of the percentage of Nest-positive cells from 44.1 to 62.5% of cell population at the response to the presence of EGF and bFGF and using the heat-inactivated serum in the culture medium. Further differentiation in culture tended to decrease of Nest-positive cell amount. Stimulation of the neuroinduction with retinoic acid resulted in decrease of the percentage of these cells in the population to 14.1%. This data allowed obtaining the nerve cell population more effective for using as a graft material in cell therapy.

Co–transplantation of macaque autologous Schwann cells and human embryonic nerve stem cells in treatment of macaque Parkinson's disease

Objective To investigate the therapeutic effects of co-transplantation with Schwann cells (SCs) and human embryonic nerve stem cells (NSCs) on macaque Parkinson's disease (PD). Methods Macaque autologous SCs and human embryonic NSCs were adopted for the treatment of macaque PD. Results Six months after transplantation, positron emission computerized tomography showed that 18F-FP-β-CIT was significantly concentrated in the injured striatum in the co-transplanted group. Immunohistochemical staining of transplanted area tissue showed migration of tyroxine hydroxylase positive cells from the transplant area to the surrounding area was significantly increased in the co-transplanted group. Conclusions Co-transplantation of SCs and NSCs could effectively cure PD in macaques. SCs harvested from the autologous peripheral nerves can avoid rejection and the ethics problems, so it is expected to be applied clinically.