Reversal of Dopaminergic Degeneration in a Parkinsonian Rat following Micrografting of Human Bone Marrow-Derived Neural Progenitors

Dopamine promotes osteogenic differentiation of PDLSCs by activating DRD1 and DRD2 during orthodontic tooth movement via ERK1/2 signaling pathway

Introduction

Orthodontic tooth movement (OTM) involves complex interactions between mechanical forces and periodontal tissue adaptation, mainly mediated by periodontal ligament cells, including periodontal ligament stem cells (PDLSCs), osteoblasts, and osteoclasts. Dopamine (DA), a neurotransmitter known for its critical role in bone metabolism, is investigated in this study for its potential to enhance osteogenic differentiation in PDLSCs, which are pivotal in OTM. This study examined the potential of DA to facilitate OTM by binding to DA receptors (D1R and D2R) and activating the ERK1/2 signaling pathway. We propose that DA's interaction with these receptors on PDLSCs could enhance osteogenic differentiation, thereby accelerating bone remodeling and reducing the duration of orthodontic treatments, which offering a novel approach to improve clinical outcomes in orthodontic care.

Methods

This study utilized a rat OTM model, micro-CT, histological analyses, and in vitro assays to investigate dopamine's effect on osteogenesis. PDLSCs were cultured and treated with DA, and cytotoxicity, osteogenic differentiation, gene and protein expression assessed.

Results

Dopamine administration significantly increased trabecular bone density and osteogenic marker expression in an OTM rat model. In vitro, DA at 10 nM optimally promoted human PDLSCs osteogenesis without affecting proliferation. Blocking DA receptors or inhibiting the ERK1/2 pathway attenuated these effects, underscoring the importance of dopaminergic signaling in tension-induced osteogenesis during OTM.

Conclusion

Taken together, our study reveals that local dopamine administration at a concentration of 10 nM not only enhances tension-induced osteogenesis in vivo but also significantly promotes osteogenic differentiation of PDLSCs in vitro through D1 and D2 receptor-mediated ERK1/2 signaling pathway activation.

The potential use of mesenchymal stem cells and their exosomes in Parkinson's disease treatment

Parkinson's disease (PD) is the second most predominant neurodegenerative disease worldwide. It is recognized clinically by severe complications in motor function caused by progressive degeneration of dopaminergic neurons (DAn) and dopamine depletion. As the current standard of treatment is focused on alleviating symptoms through Levodopa, developing neuroprotective techniques is critical for adopting a more pathology-oriented therapeutic approach. Regenerative cell therapy has provided us with an unrivalled platform for evaluating potentially effective novel methods for treating neurodegenerative illnesses over the last two decades. Mesenchymal stem cells (MSCs) are most promising, as they can differentiate into dopaminergic neurons and produce neurotrophic substances. The precise process by which stem cells repair neuronal injury is unknown, and MSC-derived exosomes are suggested to be responsible for a significant portion of such effects. The present review discusses the application of mesenchymal stem cells and MSC-derived exosomes in PD treatment.

Highlighting Immune System and Stress in Major Depressive Disorder, Parkinson's, and Alzheimer's Diseases, with a Connection with Serotonin

There is recognition that both stress and immune responses are important factors in a variety of neurological disorders. Moreover, there is an important role of several neurotransmitters that connect these factors to several neurological diseases, with a special focus in this paper on serotonin. Accordingly, it is known that imbalances in stressors can promote a variety of neuropsychiatric or neurodegenerative pathologies. Here, we discuss some facts that link major depressive disorder, Alzheimer’s, and Parkinson’s to the stress and immune responses, as well as the connection between these responses and serotonergic signaling. These are important topics of investigation which may lead to new or better treatments, improving the life quality of patients that suffer from these conditions.

Allogeneic Bone Marrow-Derived Mesenchymal Stem Cell Safety in Idiopathic Parkinson's Disease

BACKGROUND

Neuroinflammation plays a key role in PD pathogenesis, and allogeneic bone marrow-derived mesenchymal stem cells can be used as an immunomodulatory therapy.

OBJECTIVE

The objective of this study was to prove the safety and tolerability of intravenous allogeneic bone marrow-derived mesenchymal stem cells in PD patients.

METHODS

This was a 12-month single-center open-label dose-escalation phase 1 study of 20 subjects with mild/moderate PD assigned to a single intravenous infusion of 1 of 4 doses: 1, 3, 6, or 10 × 10⁶ allogeneic bone marrow-derived mesenchymal stem cells/kg, evaluated 3, 12, 24, and 52 weeks postinfusion. Primary outcome safety measures included transfusion reaction, study-related adverse events, and immunogenic responses. Secondary outcomes included impact on peripheral markers, PD progression, and changes in brain perfusion.

RESULTS

There were no serious adverse reactions related to the infusion and no responses to donor-specific human leukocyte antigens. Most common treatment-emergent adverse events were dyskinesias (20%, n = 4) with 1 emergent and 3 exacerbations; and hypertension (20%, n = 4) with 3 transient episodes and 1 requiring medical intervention. One possibly related serious adverse event occurred in a patient with a 4-year history of lymphocytosis who developed asymptomatic chronic lymphocytic leukemia. Peripheral inflammation markers appear to be reduced at 52 weeks in the highest dose including, tumor necrosis factor-α (P < 0.05), chemokine (C-C motif) ligand 22 (P < 0.05), whereas brain-derived neurotrophic factor (P < 0.05) increased. The highest dose seems to have demonstrated the most significant effect at 52 weeks, reducing the OFF state UPDRS motor, -14.4 (P < 0.01), and total, -20.8 (P < 0.05), scores.

CONCLUSION

A single intravenous infusion of allogeneic bone marrow-derived mesenchymal stem cells at doses of 1, 3, 6, or 10 × 10⁶ allogeneic bone marrow-derived mesenchymal stem cells/kg is safe, well tolerated, and not immunogenic in mild/moderate PD patients. © 2021 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Inflammatory Pre-Conditioning of Adipose-Derived Stem Cells with Cerebrospinal Fluid from Traumatic Brain Injury Patients Alters the Immunomodulatory Potential of ADSC Secretomes

Immunomodulation by adipose-tissue-derived stem cells (ADSCs) is of special interest for the alleviation of damaging inflammatory responses in central nervous system injuries. The present study explored the effects of cerebrospinal fluid (CSF) from traumatic brain injury (TBI) patients on this immunomodulatory potential of ADSCs. CSF conditioning of ADSCs increased messenger RNA levels of both pro- and anti-inflammatory genes compared to controls. Exposure of phorbol-12-myristate-13-acetate-differentiated THP1 macrophages to the secretome of CSF-conditioned ADSCs downregulated both proinflammatory (cyclooxygenase-2, tumor necrosis factor alpha) and anti-inflammatory (suppressor of cytokine signaling 3, interleukin-1 receptor antagonist, and transforming growth factor beta) genes in these cells. Interleukin-10 expression was elevated in both naïve and conditioned secretomes. ADSC secretome treatment, further, induced macrophage maturation of THP1 cells and increased the percentage of CD11b⁺, CD14⁺, CD86⁺, and, to a lesser extent, CD206⁺ cells. This, moreover, enhanced the phagocytic activity of CD14⁺ and CD86⁺ cells, though independently of pre-conditioning. Secretome exposure, finally, also induced a reduction in the percentage of CD192⁺ adherent cells in cultures of peripheral blood mononuclear cells (PBMCs) from both healthy subjects and TBI patients. This limited efficacy (of both naïve and pre-conditioned secretomes) suggests that the effects of lymphocyte-monocyte paracrine signaling on the fate of cultured PBMCs are strongest upon adherent cell populations.

Trabecular meshwork mesenchymal stem cell transplantation improve motor symptoms of parkinsonian rat model

Stem cell transplantation is a new therapeutic strategy in the treatment of neurodegenerative disorders such as Parkinson's disease (PD). Therefore, in this study, the therapeutic effects of Trabecular Meshwork Mesenchymal Stem Cells (TM-MSCs) transplantation, as a new source of mesenchymal stem cells, were evaluated in the animal model of PD. After the development and confirmation of hemi-parkinsonian rats by administration of 6-hydroxy dopamine (6-OHDA) and apomorphine-induced rotation test, green fluorescent protein (GFP) labeled TM-MSCs (normal and induced cells) were transplanted in the striatum of rats. Next, the rotation test, rotarod test, open field, passive avoidance memory tests and immunohistochemistry for tyrosine hydroxylase (TH) were done. The results showed that the number of turns significantly decreased and the improvement of motor performance was achieved after cell transplantation. However, there was no significant difference in passive avoidance memory of animals documented by shuttle box test. The number of GFP- labeled cells expressing TH significantly is increased compared to the vehicle group. Collectively, it seems that TM-MSCs and induced TM-MSCs cell transplantation have positive effects on some aspects of the animal model of PD. Other studies may reveal the potentially positive aspects of these cells in the laboratory and clinical studies.

Regulation of Noise-Induced Loss of Serotonin Transporters with Resveratrol in a Rat Model Using 4-[18F]-ADAM/Small-Animal Positron Emission Tomography

Serotonin (5-HT) plays a crucial role in modulating the afferent fiber discharge rate in the inferior colliculus, auditory cortex, and other nuclei of the ascending auditory system. Resveratrol, a natural polyphenol phytoalexin, can inhibit serotonin transporters (SERT) to increase synaptic 5-HT levels. In this study, we investigated the effects of resveratrol on noise-induced damage in the serotonergic system. Male Sprague-Dawley rats were anaesthetized and exposed to an 8-kHz tone at 116 dB for 3.5 h. Resveratrol (30 mg/kg, intraperitoneal injection [IP]) and citalopram (20 mg/kg, IP), a specific SERT inhibitor used as a positive control, were administered once a day for four consecutive days, with the first treatment occurring 2 days before noise exposure. Auditory brainstem response testing and positron emission tomography (PET) with N,N-dimethyl-2-(2-amino-4-[¹⁸F]fluorophenylthio)benzylamine (4-[¹⁸F]-ADAM, a specific radioligand for SERT) were used to evaluate functionality of the auditory system and integrity of the serotonergic system, respectively, before and after noise exposure. Finally, immunohistochemistry was performed 1 day after the last PET scan. Our results indicate that noise-induced serotonergic fiber loss occurred in multiple brain regions including the midbrain, thalamus, hypothalamus, striatum, auditory cortex, and frontal cortex. This noise-induced damage to the serotonergic system was ameliorated in response to treatment with resveratrol and citalopram. However, noise exposure increased the hearing threshold in the rats regardless of drug treatment status. We conclude that resveratrol has protective effects against noise-induced loss of SERT.

Pluripotent stem cell-based therapy for Parkinson's disease: Current status and future prospects

Parkinson's disease (PD) is one of the most common neurodegenerative disorders, which affects about 0.3% of the general population. As the population in the developed world ages, this creates an escalating burden on society both in economic terms and in quality of life for these patients and for the families that support them. Although currently available pharmacological or surgical treatments may significantly improve the quality of life of many patients with PD, these are symptomatic treatments that do not slow or stop the progressive course of the disease. Because motor impairments in PD largely result from loss of midbrain dopamine neurons in the substantia nigra pars compacta, PD has long been considered to be one of the most promising target diseases for cell-based therapy. Indeed, numerous clinical and preclinical studies using fetal cell transplantation have provided proof of concept that cell replacement therapy may be a viable therapeutic approach for PD. However, the use of human fetal cells as a standardized therapeutic regimen has been fraught with fundamental ethical, practical, and clinical issues, prompting scientists to explore alternative cell sources. Based on groundbreaking establishments of human embryonic stem cells and induced pluripotent stem cells, these human pluripotent stem cells have been the subject of extensive research, leading to tremendous advancement in our understanding of these novel classes of stem cells and promising great potential for regenerative medicine. In this review, we discuss the prospects and challenges of human pluripotent stem cell-based cell therapy for PD.

Dextran-coated iron oxide nanoparticle-improved therapeutic effects of human mesenchymal stem cells in a mouse model of Parkinson's disease

Parkinson's disease (PD) is a prevalent neurodegenerative disease characterized by the loss of dopaminergic (DA) neurons. With their migration capacity toward the sites of diseased DA neurons in the PD brain, mesenchymal stem cells (MSCs) have the potential to differentiate to DA neurons for the replacement of damaged neurons and to secrete neurotrophic factors for the protection and regeneration of diseased DA neurons; therefore MSCs show promise for the treatment of PD. In this study, for the first time, we demonstrate that dextran-coated iron oxide nanoparticles (Dex-IO NPs) can improve the therapeutic efficacy of human MSCs (hMSCs) in a mouse model of PD induced by a local injection of 6-hydroxydopamine (6-OHDA). In situ examinations not only show that Dex-IO NPs can improve the rescue effect of hMSCs on the loss of host DA neurons but also demonstrate that Dex-IO NPs can promote the migration capacity of hMSCs toward lesioned DA neurons and induce the differentiation of hMSCs to DA-like neurons at the diseased sites. We prove that in vitro Dex-IO NPs can enhance the migration of hMSCs toward 6-OHDA-damaged SH-SY5Y-derived DA-like cells, induce hMSCs to differentiate to DA-like neurons in the conditioned media derived from 6-OHDA-damaged SH-SY5Y-derived DA-like cells and promote the protection/regeneration effects of hMSCs on 6-OHDA-damaged SH-SY5Y-derived DA-like cells. We confirm the potential of MSCs for cell-based therapy for PD. Dex-IO NPs can be used as a tool to accelerate and optimize MSC therapeutics for PD applicable clinically.

Umbilical cord: an unlimited source of cells differentiable towards dopaminergic neurons

Cell replacement therapy utilizing mesenchymal stem cells as its main resource holds great promise for ultimate treatment of human neurological disorders. Parkinson's disease (PD) is a common, chronic neurodegenerative disorder hallmarked by localized degeneration of a specific set of dopaminergic neurons within a midbrain sub-region. The specific cell type and confined location of degenerating neurons make cell replacement therapy ideal for PD treatment since it mainly requires replenishment of lost dopaminergic neurons with fresh and functional ones. Endogenous as well as exogenous cell sources have been identified as candidate targets for cell replacement therapy in PD. In this review, umbilical cord mesenchymal stem cells (UCMSCs) are discussed as they provide an inexpensive unlimited reservoir differentiable towards functional dopaminergic neurons that potentially lead to long-lasting behavioral recovery in PD patients. We also present miRNAs-mediated neuronal differentiation of UCMSCs. The UCMSCs bear a number of outstanding characteristics including their non-tumorigenic, low-immunogenic properties that make them ideal for cell replacement therapy purposes. Nevertheless, more investigations as well as controlled clinical trials are required to thoroughly confirm the efficacy of UCMSCs for therapeutic medical-grade applications in PD.

Ex vivo gene therapy for the treatment of neurological disorders

Ex vivo gene therapy involves the genetic modification of cells outside of the body to produce therapeutic factors and their subsequent transplantation back into patients. Various cell types can be genetically engineered. However, with the explosion in stem cell technologies, neural stem/progenitor cells and mesenchymal stem cells are most often used. The synergy between the effect of the new cell and the additional engineered properties can often provide significant benefits to neurodegenerative changes in the brain. In this review, we cover both preclinical animal studies and clinical human trials that have used ex vivo gene therapy to treat neurological disorders with a focus on Parkinson's disease, Huntington's disease, Alzheimer's disease, ALS, and stroke. We highlight some of the major advances in this field including new autologous sources of pluripotent stem cells, safer ways to introduce therapeutic transgenes, and various methods of gene regulation. We also address some of the remaining hurdles including tunable gene regulation, in vivo cell tracking, and rigorous experimental design. Overall, given the current outcomes from researchers and clinical trials, along with exciting new developments in ex vivo gene and cell therapy, we anticipate that successful treatments for neurological diseases will arise in the near future.

Mesenchymal stem cell therapy in Parkinson's disease animal models

Parkinson's disease is a neurodegenerative disorder characterized by the loss of dopaminergic neurons in the substantia nigra, and as a consequence, by decreased dopamine levels in the striatum. Currently available therapies are not able to stop or reverse the progression of the disease. A novel therapeutic approach is based on cell therapy with stem cells, in order to replace degenerated neurons. Among stem cells, mesenchymal stem cells seemed the most promising thanks to their capacities to differentiate toward dopaminergic neurons and to release neurotrophic factors. Indeed, mesenchymal stem cells are able to produce different molecules with immunomodulatory, neuroprotective, angiogenic, chemotactic effects and that stimulate differentiation of resident stem cells. Mesenchymal stem cells were isolated for the first time from bone marrow, but can be collected also from adipose tissue, umbilical cord and other tissues. In this review, we focused our attention on mesenchymal stem cells derived from different sources and their application in Parkinson's disease animal models.

Dopaminergic-primed fetal liver mesenchymal stromal-like cells can reverse parkinsonian symptoms in 6-hydroxydopamine-lesioned mice

BACKGROUND AIMS

Cell replacement therapy is considered a promising alternative in the treatment of degenerative diseases, and in this context, mesenchymal stromal cells (MSCs) have been proposed for transplantation in Parkinson disease (PD). Thus far, the results of animal studies are found to be inconsistent and inconclusive regarding the therapeutic ability of the cells. This study investigated the efficacy of fetal liver (FL)-MSC-derived dopaminergic (DA) neuronal primed cells for correction of parkinsonian symptoms in mice.

METHODS

FL-MSCs were differentiated for 21 days in the presence of a combination of neurotropic factors. The extent of cellular reprogramming was analyzed by quantitative polymerase chain reaction for DA-specific neuronal gene expressions and protein expressions by immuno-cytochemistry. The functionality of the cells was determined by electrophysiology and dopamine release assays. Ten-day-primed neuron-like cells or unprimed MSCs were transplanted into the 6-hydroxydopamine (6-OHDA)-lesioned striatum using a stereotaxic device. Dopamine-secreting properties and behavioral studies were used to assess improvement of parkinsonian symptoms.

RESULTS

The differentiated cells expressed DA-specific genes and proteins, while exhibiting a high level of voltage-gated potassium current. Furthermore, neuronal primed cells differentiated into tyrosine hydroxylase immunoreactive and dopamine-secreting functional neuron-like cells. Symptomatic correction of PD in the recipient mice within 2 months of transplantation was also observed.

DISCUSSION

FL-MSC-derived primed neuron-like cells integrated into the striatum of PD mice, improving parkinsonian symptoms. This study demonstrates an effective cell-based therapy for PD.

Adipose-derived human mesenchymal stem cells induce long-term neurogenic and anti-inflammatory effects and improve cognitive but not motor performance in a rat model of Parkinson's disease

BACKGROUND

Mesenchymal stem cells (MSC) are easily harvested, and possess anti-inflammatory and trophic properties. Furthermore, MSC promote neuroprotection and neurogenesis, which could greatly benefit neurodegenerative disorders, such as Parkinson's disease.

METHODS

MSC were transplanted one week after 6-hydroxydopamine lesioning and effects were evaluated after 6 months.

RESULTS

MSC localized around the substantia nigra and the arachnoid mater, expressing pericyte and endothelial markers. MSC protected dopamine levels and upregulated peripheral anti-inflammatory cytokines. Furthermore, adipose-derived MSC increased neurogenesis in hippocampal and subventricular regions, and boosted memory functioning.

CONCLUSION

Considering that hyposmia and loss of memory function are two major nonmotor symptoms in Parkinson's disease, transplants with modulatory effects on the hippocampus and subventricular zone could provide a disease-modifying therapy.

Resveratrol augments therapeutic efficiency of mouse bone marrow mesenchymal stem cell-based therapy in experimental autoimmune encephalomyelitis

Experimental autoimmune encephalitis (EAE) is an inflammatory demyelinating disease, which served as a useful model providing considerable insights into the pathogenesis of multiple sclerosis (MS). Mouse bone marrow mesenchymal stem cells (mBM-MSC) were shown to have neuroprotection capabilities in EAE. Resveratrol is a small polyphenolic compound and possess therapeutic activity in various immune-mediated diseases. The sensitivity of mBM-MSCs to resveratrol was determined by an established cell-viability assay. Resveratrol-treated mBM-MSCs were also characterized with flow cytometry using MSC-specific surface markers and analyzed for their multiple differentiation capacities. EAE was induced in C57BL/6 mice by immunization with MOG35-55. Interferon gamma (IFN-γ)/tumor necrosis factor alpha (TNF-α) and interleukin-4 (IL-4)/interleukin-10 (IL-10), the hallmark cytokines that direct T helper type 1 (Th1) and Th2 development, were detected with enzyme-linked immunosorbent assay (ELISA). In vivo efficacy experiments showed that mBM-MSCs or resveratrol alone led to a significant reduction in clinical scores, and combined treatment resulted in even more prominent reduction. The combined treatment with mBM-MSCs and resveratrol enhanced the immunomodulatory effects, showing suppressed proinflammatory cytokines (IFN-γ, TNF-α) and increased anti-inflammatory cytokines (IL-4, IL-10). The combination of mBM-MSCs and resveratrol provides a novel potential experimental protocol for alleviating EAE symptoms.

Stem cell transplantation therapy in Parkinson's disease

Ineffective therapeutic treatments and inadequate repair ability in the central nervous system are disturbing problems for several neurological diseases. Fortunately, the development of clinically applicable populations of stem cells has provided an avenue to overcome the failure of endogenous repair systems and substitute new cells into the damaged brain. However, there are still several existing obstacles to translating into clinical application. Here we review the stem-cell based therapies for Parkinson’s disease and discuss the potential advantages and drawbacks. We hope this review may provide suggestions for viable strategies to overcome the current technical and biological issues associated with the application of stem cells in Parkinson’s disease.

Mesenchymal stromal SB623 cell implantation mitigates nigrostriatal dopaminergic damage in a mouse model of Parkinson's disease

Regenerative medicine for the treatment of motor features in Parkinson's disease (PD) is a promising therapeutic option. Donor cells can simultaneously address multiple pathological mechanisms while responding to the needs of the host tissue. Previous studies have demonstrated that mesenchymal stromal cells (MSCs) promote recovery using various animal models of PD. SanBio Inc. has developed a novel cell type designated SB623, which are adult bone marrow-derived MSCs transfected with Notch intracellular domain. In this preclinical study, SB623 cells protected against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced nigrostriatal injury when transplanted unilaterally into C57BL/6 mouse striatum 3 days prior to toxin exposure. Specifically, mice with the SB623 cell transplants revealed significantly higher levels of striatal dopamine, tyrosine hydroxylase immunoreactivity and stereological nigral cell counts in the ipsilateral hemisphere vs vehicle-treated mice following MPTP administration. Interestingly, improvement in markers of striatal dopaminergic integrity was also noted in the contralateral hemisphere. These data indicate that MSCs transplantation, specifically SB623 cells, may represent a novel therapeutic option to ameliorate damage related to PD, not only at the level of striatal terminals (i.e. the site of implantation) but also at the level of the nigral cell body. Copyright © 2015 John Wiley & Sons, Ltd.

Induced neural stem/precursor cells for fundamental studies and potential application in neurodegenerative diseases

Recent research has shown that defined sets of exogenous factors are sufficient to convert rodent and human somatic cells directly into induced neural stem cells or neural precursor cells (iNSCs/iNPCs). The process of transdifferentiation bypasses the step of a pluripotent state and reduces the risk of tumorigenesis and genetic instability while retaining the self-renewing capacity. This iNSC/iNPC technology has fueled much excitement in regenerative medicine, as these cells can be differentiated into target cells for re placement therapy for neurodegenerative diseases. Patients' somatic cell-derived iNSCs/iNPCs have also been proposed to serve as disease models with potential value in both fundamental studies and clinical applications. This review focuses on the mechanisms, techniques, and app lications of iNSCs/iNPCs from a series of related studies, as well as further efforts in designing novel strategies using iNSC/iNPC technology and its potential applications in neurodegenerative diseases.

Human umbilical cord mesenchymal stem cells infected with adenovirus expressing HGF promote regeneration of damaged neuron cells in a Parkinson's disease model

Parkinson's disease (PD) is a neurodegenerative movement disorder that is characterized by the progressive degeneration of the dopaminergic (DA) pathway. Mesenchymal stem cells derived from human umbilical cord (hUC-MSCs) have great potential for developing a therapeutic agent as such. HGF is a multifunctional mediator originally identified in hepatocytes and has recently been reported to possess various neuroprotective properties. This study was designed to investigate the protective effect of hUC-MSCs infected by an adenovirus carrying the HGF gene on the PD cell model induced by MPP+ on human bone marrow neuroblastoma cells. Our results provide evidence that the cultural supernatant from hUC-MSCs expressing HGF could promote regeneration of damaged PD cells at higher efficacy than the supernatant from hUC-MSCs alone. And intracellular free Ca²⁺ obviously decreased after treatment with cultural supernatant from hUC-MSCs expressing HGF, while the expression of CaBP-D28k, an intracellular calcium binding protein, increased. Therefore our study clearly demonstrated that cultural supernatant of MSC overexpressing HGF was capable of eliciting regeneration of damaged PD model cells. This effect was probably achieved through the regulation of intracellular Ca²⁺ levels by modulating of CaBP-D28k expression.

Stem cells and motor recovery after stroke

In stroke patients with severe persistent neurological deficits, alternative therapeutic modalities are limited. Stem cell therapy might be an opportunity when the safety profile of this approach will be achieved. This review will give possible mechanisms of restoration of function in animals and a statement of clinical trials in humans. The sources of neural stem cells for therapeutic use will be detailed. Potentials mechanisms of transplanted cell-mediated recovery are described with a particular emphasis on ipsilesional post-stroke plasticity. The optimal conditions for cell transplant therapy after stroke are evoked but not yet clearly defined. Finally, since multimodality imaging will be crucial in the post-transplantation patient assessment, the final part describes recent advances in the in vivo monitoring of repair progress.

Transplantation of mesenchymal stem cells: a future therapy for Parkinson’s disease?

ABSTRACT: 

Parkinson’s disease (PD) is a common, progressive neurodegenerative disorder associated with a loss of dopaminergic cells in the substantia nigra pars compacta and a lack of dopamine in the striatum. To halt or reverse this disease, neurorestorative approaches or neuroprotective treatments are urgently needed. Recently, the first clinical trials transplanting mesenchymal stem cells (MSCs) have been performed in PD. MSCs are adult stem cells abundant in several tissues, such as the umbilical cord, the bone marrow, the adipose tissue and other tissues. These cells are multipotent, and able to synthesize and secrete a wide spectrum of biologically active factors. MSCs of various origins have been explored as possible substrates for cell therapy in PD animal models. In this review, we summarize MSC-based experimental transplantation studies in PD, and discuss biological mechanisms that may explain the effects of MSC seen in PD models. Furthermore, we critically evaluate the recent clinical transplantation trials using MSCs in patients with PD.

Comparison of the neuropoietic activity of gene-modified versus parental mesenchymal stromal cells and the identification of soluble and extracellular matrix-related neuropoietic mediators

Introduction

Transplanting mesenchymal stromal cells (MSCs) or their derivatives into a neurodegenerative environment is believed to be beneficial because of the trophic support, migratory guidance, immunosuppression, and neurogenic stimuli they provide. SB623, a cell therapy for the treatment of chronic stroke, currently in a clinical trial, is derived from bone marrow MSCs by using transient transfection with a vector encoding the human Notch1 intracellular domain. This creates a new phenotype, which is effective in experimental stroke, exhibits immunosuppressive and angiogenic activity equal or superior to parental MSCs in vitro, and produces extracellular matrix (ECM) that is exceptionally supportive for neural cell growth. The neuropoietic activity of SB623 and parental MSCs has not been compared, and the SB623-derived neuropoietic mediators have not been identified.

Methods

SB623 or parental MSCs were cocultured with rat embryonic brain cortex cells on cell-derived ECM in a previously characterized quantitative neuropoiesis assay. Changes in expression of rat neural differentiation markers were quantified by using rat-specific qRT-PCR. Human mediators were identified by using expression profiling, an enzymatic crosslinking activity, and functional interference studies by means of blocking antibodies, biologic inhibitors, and siRNA. Cocultures were immunolabeled for presynaptic vesicular transporters to assess neuronal specialization.

Results

Among six MSC/SB623 pairs, SB623 induced expression of rat neural precursor, oligodendrocyte, and astrocyte markers on average 2.6 to 3 times stronger than did their parental MSCs. SB623 expressed significantly higher FGF2, FGF1, and BMP4, and lower FGFR1 and FGFR2 levels; and human FGF1, FGF2, BMPs, and HGF were implicated as neuropoietic mediators. Neural precursors grew faster on SB623- than on MSC-derived ECM. SB623 exhibited higher expression levels and crosslinking activity of tissue transglutaminase (TGM2). TGM2 silencing reduced neural precursor growth on SB623-ECM. SB623 also promoted the induction of GABA-ergic, but not glutamatergic, neurons more effectively than did MSCs.

Conclusions

These data demonstrate that SB623 cells tend to support neural cell growth more effectively than their parental MSCs and identify both soluble and insoluble mediators responsible, at least in part, for enhanced neuropoietic potency of SB623. The neuropoiesis assay is a useful tool for identifying beneficial factors produced by MSCs and their derivatives.

The secretome of mesenchymal stem cells: potential implications for neuroregeneration

Mesenchymal stem cells have shown regenerative properties in many tissues. This feature had originally been ascribed to their multipotency and thus their ability to differentiate into tissue-specific cells. However, many researchers consider the secretome of mesenchymal stem cells the most important player in the observed reparative effects of these cells. In this review, we specifically focus on the potential neuroregenerative effect of mesenchymal stem cells, summarize several possible mechanisms of neuroregeneration and list key factors mediating this effect. We illustrate examples of mesenchymal stem cell treatment in central nervous system disorders including stroke, neurodegenerative disorders (such as Parkinson's disease, Huntington's disease, multiple system atrophy and cerebellar ataxia) and inflammatory disease (such as multiple sclerosis). We specifically highlight studies where mesenchymal stem cells have entered clinical trials.

Quantitative microplate assay for studying mesenchymal stromal cell-induced neuropoiesis

Transplanting mesenchymal stromal cells (MSCs) or their derivatives in a neurodegenerative environment is believed to be beneficial because of the trophic support, migratory guidance, and neurogenic stimuli they provide. There is a growing need for in vitro models of mesenchymal-neural cell interactions to enable identification of mediators of the MSC activity and quantitative assessment of neuropoietic potency of MSC preparations. Here, we characterize a microplate-format coculture system in which primary embryonic rat cortex cells are directly cocultured with human MSCs on cell-derived extracellular matrix (ECM) in the absence of exogenous growth factors. In this system, expression levels of the rat neural stem/early progenitor marker nestin, as well as neuronal and astrocytic markers, directly depended on MSC dose, whereas an oligodendrogenic marker exhibited a biphasic MSC-dose response, as measured using species-specific quantitative reverse transcription-polymerase chain reaction in total cell lysates and confirmed using immunostaining. Both neural cell proliferation and differentiation contributed to the MSC-mediated neuropoiesis. ECM's heparan sulfate proteoglycans were essential for the growth of the nestin-positive cell population. Neutralization studies showed that MSC-derived fibroblast growth factor 2 was a major and diffusible inducer of rat nestin, whereas MSC-derived bone morphogenetic proteins (BMPs), particularly, BMP4, were astrogenesis mediators, predominantly acting in a coculture setting. This system enables analysis of multifactorial MSC-neural cell interactions and can be used for elucidating the neuropoietic potency of MSCs and their derivative preparations.

Tracing synaptic connectivity onto embryonic stem cell-derived neurons

Transsynaptic circuit tracing using genetically modified rabies virus (RV) is an emerging technology for identifying synaptic connections between neurons. Complementing this methodology, it is now possible to assay the basic molecular and cellular properties of neuronal lineages derived from embryonic stem cells (ESCs) in vitro, and these properties are under intense investigation toward devising cell replacement therapies. Here, we report the generation of a novel mouse ESC (mESC) line that harbors the genetic elements to allow RV-mediated transsynaptic circuit tracing in ESC-derived neurons and their synaptic networks. To facilitate transsynaptic tracing, we have engineered a new reporter allele by introducing cDNA encoding tdTomato, the Rabies-G glycoprotein, and the avian TVA receptor into the ROSA26 locus by gene targeting. We demonstrate high-efficiency differentiation of these novel mESCs into functional neurons, show their capacity to synaptically connect with primary neuronal cultures as evidenced by immunohistochemistry and electrophysiological recordings, and show their ability to act as source cells for presynaptic tracing of neuronal networks in vitro and in vivo. Together, our data highlight the potential for using genetically engineered stem cells to investigate fundamental mechanisms of synapse and circuit formation with unambiguous identification of presynaptic inputs onto neuronal populations of interest.

Intranasal Delivery of Neural Stem Cells: A CNS-specific, Non-invasive Cell-based Therapy for Experimental Autoimmune Encephalomyelitis

The therapeutic potential of adult neural stem cells (aNSCs) has been shown in EAE, an animal model of MS, administered by either i.c.v. or i.v. injection. However, i.c.v. is an invasive approach, while the i.v. route of aNSCs is associated with a non-specific immune suppression in the periphery. Here we demonstrate that intranasal (i.n.) delivery of fluorescently labeled aNSCs resulted in their appearance in the olfactory bulb, cortex, hippocampus, striatum, brainstem, and spinal cord. These cells induce functional recovery from ongoing EAE similar to that achieved with i.v. injected aNSCs, with comparable anti-inflammatory and remeylination effects in CNS inflammatory foci. Importantly, unlike the peripheral immune suppression brought about by i.v. NSCs, intranasal delivery did not influence peripheral immune responses. We conclude that aNSCs can be reliably delivered to the CNS via the nasal route to induce functional recovery and confer immunomodulation and remyelination in EAE. Intranasal administration of NSCs provides a highly promising, noninvasive and CNS-specific alternative to current cell-based approaches in treating EAE.

PET imaging of serotonin transporters with 4-[18F]-ADAM in a Parkinsonian rat model

This study was undertaken to address the effects of fetal mesencephalic tissue transplantation on the serotonin system in a rat model of Parkinson's disease (PD) while also investigating the usefulness of 4-[18F]-ADAM (a serotonin transporter imaging agent) coupled with micro-PET for imaging serotonin transporters (SERTs). A PD model was induced by unilateral injection of 6-hydroxydopamine (6-OHDA) into the right medial forebrain bundle of the nigrostriatal pathway, while cell transplantation was performed via intrastriatal injection of mesencephalic brain tissue dissected from embryonic (E14) rats. The 4-[18F]-ADAM/micro-PET scanning was performed following both 6-OHDA lesioning and transplantation. Immunohistochemistry (IHC) studies were also performed following the final PET scan, and the results were compared to show a 17-43% decrease in the specific uptake ratio (SUR) and a 23-52% decrease in serotonin transporter immunoreactivity (SERT-ir) within various brain regions on the lesioned side. The number of methamphetamine-induced rotations also decreased significantly at the 4th week postgraft. In addition, striatal SUR and the SERT-ir levels were restored to 77% and 83% 5 weeks postgraft. These results suggest that Parkinson's disease also affects the serotonergic system, while both the dopaminergic and serotonergic systems can be partially restored in a rat model of PD after E14 mesencephalic tissue transplantation. In addition, we have also determined that 4-[18F]-ADAM/micro-PET can be used to detect serotonergic neuron loss, monitor the progress of Parkinson's disease, and oversee the effectiveness of therapy.

ZNF281 knockdown induced osteogenic differentiation of human multipotent stem cells in vivo and in vitro

ZNF281 is one of the core transcription factors in embryonic stem cells (ESCs) and has activation and repression roles in the transcription of ESC genes. A known target molecule of Zfp281 (the mouse homologue of ZNF281) is Nanog. However, NANOG is not expressed in most human multipotent stem cells (hMSCs). Here, we investigated the roles of ZNF281 with a gain- and loss-of-function study. The knockdown of ZNF281 in vivo and in vitro resulted in spontaneous osteochondrogenic differentiation and reduced the proliferation of hMSCs, as determined by cell morphology and molecular markers. When ZNF281-knockdown hMSCs were subcutaneously implanted into mice along with β-tricalcium phosphate (β-TCP), many cells were converted into osteoblasts within 4 weeks. In contrast, the overexpression of ZNF281 in hMSCs resulted in accelerated proliferation. The expression pattern of ZNF281 correlated well with the expression of β-CATENIN during differentiation and in the gain/loss-of-function study in hMSCs. The binding of ZNF281 to the promoter region of β-CATENIN was observed using a chromatin immunoprecipitation (ChIP) assay. In conclusion, we propose that ZNF281 plays an important role in the maintenance and osteogenic differentiation of stem cells via the transcriptional regulation of genes including β-CATENIN.

Docosahexaenoic Acid Promotes Dopaminergic Differentiation in Induced Pluripotent Stem Cells and Inhibits Teratoma Formation in Rats with Parkinson-Like Pathology

Parkinson's disease (PD) is a neurodegenerative disorder characterized by the degeneration of dopaminergic (DA) neurons in the midbrain. Induced pluripotent stem (iPS) cells have shown potential for differentiation and may become a resource of functional neurons for the treatment of PD. However, teratoma formation is a major concern for transplantation-based therapies. This study examined whether functional neurons could be efficiently generated from iPS cells using a five-step induction procedure combined with docosahexaenoic acid (DHA) treatment. We demonstrated that DHA, a ligand for the RXR/Nurr1 heterodimer, significantly activated expression of the Nurr1 gene and the Nurr1-related pathway in iPS cells. DHA treatment facilitated iPS differentiation into tyrosine hydroxylase (TH)-positive neurons in vitro and in vivo and functionally increased dopamine release in transplanted grafts in PD-like animals. Furthermore, DHA dramatically upregulated the endogenous expression levels of neuroprotective genes ( Bcl-2, Bcl-xl, brain-derived neurotrophic factor, and glial cell-derived neurotrophic factor) and protected against 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced apoptosis in iPS-derived neuronal precursor cells. DHA-treated iPS cells significantly improved the behavior of 6-hydroxydopamine (6-OHDA)-treated PD-like rats compared to control or eicosapentaenoic acid-treated group. Importantly, the in vivo experiment suggests that DHA induces the differentiation of functional dopaminergic precursors and improves the abnormal behavior of 6-OHDA-treated PD-like rats by 4 months after transplantation. Furthermore, we found that DHA treatment in iPS cell-grafted rats significantly downregulated the mRNA expression of embryonic stem cell-specific genes (Oct-4 and c-Myc) in the graft and effectively blocked teratoma formation. Importantly, 3 Tesla-magnetic resonance imaging and ex vivo green fluorescence protein imaging revealed that no teratomas were present in transplanted grafts of DHA-treated iPS-derived DA neurons 4 months after implantation. Therefore, our data suggest that DHA plays a crucial role in iPS differentiation into functional DA neurons and that this approach could provide a novel therapeutic approach for PD treatment.

Comparing the immunosuppressive potency of naïve marrow stromal cells and Notch-transfected marrow stromal cells

Background

SB623 cells are expanded from marrow stromal cells (MSCs) transfected with a Notch intracellular domain (NICD)-expressing plasmid. In stroke-induced animals, these cells reduce infarct size and promote functional recovery. SB623 cells resemble the parental MSCs with respect to morphology and cell surface markers despite having been in extended culture. MSCs are known to have immunosuppressive properties; whether long-term culture of MSCs impact their immunomodulatory activity has not been addressed.

Methods

To assess the possible senescent properties of SB623 cells, we performed cell cycle related assays and beta-galactosidase staining. To assess the immunomodulatory activity of these expanded NICD-transfected MSCs, we performed co-cultures of SB623 cells or MSCs with either enriched human T cells or monocytes and assessed cytokine production by flow cytometry. In addition, we monitored the immunosuppressive activity of SB623 cells in both allogenic and xenogenic mixed lymphocyte reaction (MLR).

Results

Compared to MSCs, we showed that a small number of senescent-like cells appear in each lot of SB623 cells. Nevertheless, we demonstrated that these cells suppress human T cell proliferation in both the allogeneic and xenogeneic mixed lymphocyte reaction (MLR) in a manner comparable to MSCs. IL-10 producing T cells were generated and monocyte-dendritic cell differentiation was dampened by co-culture with SB623 cells. Compared to the parental MSCs, SB623 cells appear to exert a greater inhibitory impact on the maturation of dendritic cells as demonstrated by a greater reduction in the surface expression of the co-stimulatory molecule, CD86.

Conclusion

The results demonstrated that the immunosuppressive activity of the expanded NICD-transfected MSCs is comparable to the parental MSCs, in spite of the appearance of a small number of senescent-like cells.

Human Umbilical Cord Blood-Derived Mesenchymal Stem Cells Protect against Neuronal Cell Death and Ameliorate Motor Deficits in Niemann Pick Type C1 Mice

Niemann Pick disease type C1 (NPC) is an autosomal recessive disease characterized by progressive neurological deterioration leading to premature death. In this study, we hypothesized that human umbilical cord blood-derived mesenchymal stem cells (hUCB-MSCs) have the multifunctional abilities to ameliorate NPC symptoms in the brain. To test this hypothesis, hUCB-MSCs were transplanted into the hippocampus of NPC mice in the early asymptomatic stage. This transplantation resulted in the recovery of motor function in the Rota Rod test and impaired cholesterol homeostasis leading to increased levels of cholesterol efflux-related genes such as LXRα, ABCA1, and ABCG5 while decreased levels of 3-hydroxy-3-methylglutaryl coenzyme A reductase were observed in NPC mice. In the cerebrum, hUCB-MSCs enhanced neuronal cell survival and proliferation, where they directly differentiated into electrically active MAP2-positive neurons as demonstrated by whole-cell patch clamping. In addition, we observed that hUCB-MSCs reduced Purkinje neuronal loss by suppression of inflammatory and apoptotic signaling in the cerebellum as shown by immunohistochemistry. We further investigated how hUCB-MSCs enhance cellular survival and inhibit apoptosis in NPC mice. Neuronal cell survival was associated with increased PI3K/AKT and JAK2/STAT3 signaling; moreover, hUCB-MSCs modulated the levels of GABA/glutamate transporters such as GAT1, EAAT2, EAAT3, and GAD6 in NPC mice as assessed by Western blot analysis. Taken together, our findings suggest that hUCB-MSCs might play multifunctional roles in neuronal cell survival and ameliorating motor deficits of NPC mice.

Strategies for the Development of Cell Lines for Ex Vivo Gene Therapy in the Central Nervous System

Disorders of the central nervous system (CNS) as a result of trauma or ischemic or neurodegenerative processes still pose a challenge for modern medicine. Due to the complexity of the CNS, and in spite of the advances in the knowledge of its anatomy, pharmacology, and molecular and cellular biology, treatments for these diseases are still limited. The development of cell lines as a source for transplantation into the damaged CNS (cell therapy), and more recently their genetic modification to favor the expression and delivery of molecules with therapeutic potential (ex vivo gene therapy), are some of the techniques used in search of novel restorative strategies. This article reviews the different approaches that have been used and perfected during the last decade to generate cell lines and their use in experimental models of neuronal damage, and evaluates the prospects of applying these methods to treat CNS disorders.

Role of mesenchymal stem cells in neurogenesis and nervous system repair

Bone marrow-derived mesenchymal stem cells (MSCs) are attractive candidates for use in regenerative medicine since they are easily accessible and can be readily expanded in vivo, and possess unique immunogenic properties. Moreover, these multipotent cells display intriguing environmental adaptability and secretory capacity. The ability of MSCs to migrate and engraft in a range of tissues has received significant attention. Evidence indicating that MSC transplantation results in functional improvement in animal models of neurological disorders has highlighted exciting potential for their use in neurological cell-based therapies. The manner in which MSCs elicit positive effects in the damaged nervous system remains unclear. Cell fusion and/or 'transdifferentiation' phenomena, by which MSCs have been proposed to adopt neural cell phenotypes, occur at very low frequency and are unlikely to fully account for observed neurological improvement. Alternatively, MSC-mediated neural recovery may result from the release of soluble molecules, with MSC-derived growth factors and extracellular matrix components influencing the activity of endogenous neural cells. This review discusses the potential of MSCs as candidates for use in therapies to treat neurological disorders and the molecular and cellular mechanisms by which they are understood to act.

Recent progress in cell therapy for basal ganglia disorders with emphasis on menstrual blood transplantation in stroke

Cerebrovascular diseases are the third leading cause of death and the primary cause of long-term disability in the United States. The only approved therapy for stroke is tPA, strongly limited by the short therapeutic window and hemorrhagic complications, therefore excluding most patients from its benefits. Parkinson's and Huntington's disease are the other two most studied basal ganglia diseases and, as stroke, have very limited treatment options. Inflammation is a key feature in central nervous system disorders and it plays a dual role, either improving injury in early phases or impairing neural survival at later stages. Stem cells can be opportunely used to modulate inflammation, abrogate cell death and, therefore, preserve neural function. We here discuss the role of stem cells as restorative treatments for basal ganglia disorders, including Parkinson's disease, Huntington's disease and stroke, with special emphasis to the recently investigated menstrual blood stem cells. We highlight the availability, proliferative capacity, pluripotentiality and angiogenic features of these cells and explore their present and future experimental and clinical applications.

Glial cell line-derived neurotrophic factor-secreting genetically modified human bone marrow-derived mesenchymal stem cells promote recovery in a rat model of Parkinson's disease

Parkinson's disease (PD) is a neurodegenerative disease characterized by progressive degeneration of nigrostriatal dopaminergic (DA) neurons. The therapeutic potential of glial cell line-derived neurotrophic factor (GDNF), the most potent neurotrophic factor for DA neurons, has been demonstrated in many experimental models of PD. However, chronic delivery of GDNF to DA neurons in the brain remains an unmet challenge. Here, we report the effects of GDNF-releasing Notch-induced human bone marrow-derived mesenchymal stem cells (MSC) grafted into striatum of the 6-hydroxydopamine (6-OHDA) progressively lesioned rat model of PD. Human MSC, obtained from bone marrow aspirates of young, healthy adult volunteers, were transiently transfected with the intracellular domain of the Notch1 gene (NICD) to generate SB623 cells. SB623 cells expressing GDNF and/or humanized Renilla green fluorescent protein (hrGFP) following lentiviral transduction or nontransduced cells were stereotaxically placed into rat striatum 1 week after a unilateral partial 6-OHDA striatal lesion. At 4 weeks, rats that had received GDNF-transduced SB623 cells had significantly decreased amphetamine-induced rotation compared with control rats, although this effect was not observed in rats that received GFP-transduced or nontransduced SB623 cells. At 5 weeks, rejuvenated tyrosine hydroxylase-immunoreactive (TH-IR) fibers that appeared to be host DA axons were observed in and around grafts. This effect was more prominent in rats that received GDNF-secreting cells and was not observed in controls. These observations suggest that human bone-marrow derived MSC, genetically modified to secrete GDNF, hold potential as an allogeneic or autologous stem cell therapy for PD.

Mesenchymal stem cells at the intersection of cell and gene therapy

IMPORTANCE OF THE FIELD

Mesenchymal stem cells have the ability to differentiate into osteoblasts, chondrocytes and adipocytes. Along with differentiation, MSCs can modulate inflammation, home to damaged tissues and secrete bioactive molecules. These properties can be enhanced through genetic-modification that would combine the best of both cell and gene therapy fields to treat monogenic and multigenic diseases.

AREAS COVERED IN THIS REVIEW

Findings demonstrating the immunomodulation, homing and paracrine activities of MSCs followed by a summary of the current research utilizing MSCs as a vector for gene therapy, focusing on skeletal disorders, but also cardiovascular disease, ischemic damage and cancer.

WHAT THE READER WILL GAIN

MSCs are a possible therapy for many diseases, especially those related to the musculoskeletal system, as a standalone treatment, or in combination with factors that enhance the abilities of these cells to migrate, survive or promote healing through anti-inflammatory and immunomodulatory effects, differentiation, angiogenesis or delivery of cytolytic or anabolic agents.

TAKE HOME MESSAGE

Genetically-modified MSCs are a promising area of research that would be improved by focusing on the biology of MSCs that could lead to identification of the natural and engrafting MSC-niche and a consensus on how to isolate and expand MSCs for therapeutic purposes.

Clinical potential of intravenous neural stem cell delivery for treatment of neuroinflammatory disease in mice?

While neural stem cells (NSCs) are widely expected to become a therapeutic agent for treatment of severe injuries to the central nervous system (CNS), currently there are only few detailed preclinical studies linking cell fate with experimental outcome. In this study, we aimed to validate whether IV administration of allogeneic NSC can improve experimental autoimmune encephalomyelitis (EAE), a well-established animal model for human multiple sclerosis (MS). For this, we cultured adherently growing luciferase-expressing NSCs (NSC-Luc), which displayed a uniform morphology and expression profile of membrane and intracellular markers, and which displayed an in vitro differentiation potential into neurons and astrocytes. Following labeling with green fluorescent micron-sized iron oxide particles (f-MPIO-labeled NSC-Luc) or lentiviral transduction with the enhanced green fluorescent protein (eGFP) reporter gene (NSC-Luc/eGFP), cell implantation experiments demonstrated the intrinsic survival capacity of adherently cultured NSC in the CNS of syngeneic mice, as analyzed by real-time bioluminescence imaging (BLI), magnetic resonance imaging (MRI), and histological analysis. Next, EAE was induced in C57BL/6 mice followed by IV administration of NSC-Luc/eGFP at day 7 postinduction with or without daily immunosuppressive therapy (cyclosporine A, CsA). During a follow-up period of 20 days, the observed clinical benefit could be attributed solely to CsA treatment. In addition, histological analysis demonstrated the absence of NSC-Luc/eGFP at sites of neuroinflammation. In order to investigate the absence of therapeutic potential, BLI biodistribution analysis of IV-administered NSC-Luc/eGFP revealed cell retention in lung capillaries as soon as 1-min postinjection, resulting in massive inflammation and apoptosis in lung tissue. In summary, we conclude that IV administration of NSCs currently has limited or no therapeutic potential for neuroinflammatory disease in mice, and presumably also for human MS. However, given the fact that grafted NSCs have an intrinsic survival capacity in the CNS, their therapeutic exploitation should be further investigated, and-in contrast to several other reports-will most likely be highly complex.

Feasibility of combination allogeneic stem cell therapy for spinal cord injury: a case report

Cellular therapy for spinal cord injury (SCI) is overviewed focusing on bone marrow mononuclear cells, olfactory ensheathing cells, and mesenchymal stem cells. A case is made for the possibility of combining cell types, as well as for allogeneic use. We report the case of 29 year old male who suffered a crush fracture of the L1 vertebral body, lacking lower sensorimotor function, being a score A on the ASIA scale. Stem cell therapy comprised of intrathecal administration of allogeneic umbilical cord blood ex-vivo expanded CD34 and umbilical cord matrix MSC was performed 5 months, 8 months, and 14 months after injury. Cell administration was well tolerated with no adverse effects observed. Neuropathic pain subsided from intermittent 10/10 to once a week 3/10 VAS. Recovery of muscle, bowel and sexual function was noted, along with a decrease in ASIA score to "D". This case supports further investigation into allogeneic-based stem cell therapies for SCI.

Light deprivation induces depression-like behavior and suppresses neurogenesis in diurnal mongolian gerbil (Meriones unguiculatus)

Recent evidence suggests that adult neurogenesis contributes to the pathophysiology of different psychiatric disorders, including depressive disorder, anxiety disorder, and schizophrenia. Seasonal affective disorder (SAD) is a specific form of recurrent depressive disorder that can be induced by shortened light period. It is unclear yet whether neurogenesis is affected in SAD or under altered light/dark cycle. The present study aims at examining whether neurogenesis and dendritic growth of immature neurons are affected in Mongolian gerbils, a mainly diurnal rodent, under light deprivation. Animals were divided into two groups: the control (kept in 12 h light:12 h dark) and the light-deprived groups (kept in 24 h dark). Depression-like behaviors and neurogenesis were assessed after 2 weeks. Compared with the control group, light-deprived gerbils showed increased immobile time in the tail suspension test and forced swimming test, which indicates induction of depression-like behavior. Cell proliferation in both the hippocampal and subventricular zone were significantly decreased in the light-deprived group, which also showed a decreased neuronal differentiation. Dendritic maturation of immature neurons was suppressed by light deprivation, which is revealed by doublecortin staining and Sholl analysis. The results revealed that the light/dark cycle exerts impacts on neurogenesis and maturation of new neurons. Additionally, the current experiment may offer a model for exploring the relationship among daylight exposure, circadian cycles, depressive behavior, and the underlying mechanisms.

Stem cell research in cell transplantation: sources, geopolitical influence, and transplantation

If the rapidly progressing field of stem cell research reaches its full potential, successful treatments and enhanced understanding of many diseases are the likely results. However, the full potential of stem cell science will only be reached if all possible avenues can be explored and on a worldwide scale. Until 2009, the US had a highly restrictive policy on obtaining cells from human embryos and fetal tissue, a policy that pushed research toward the use of adult-derived cells. Currently, US policy is still in flux, and retrospective analysis does show the US lagging behind the rest of the world in the proportional increase in embryonic/fetal stem cell research. The majority of US studies being on either a limited number of cell lines, or on cells derived elsewhere (or funded by other sources than Federal) rather than on freshly isolated embryonic or fetal material. Neural, mesenchymal, and the mixed stem cell mononuclear fraction are the most commonly investigated types, which can generally be classified as adult-derived stem cells, although roughly half of the neural stem cells are fetal derived. Other types, such as embryonic and fat-derived stem cells, are increasing in their prominence, suggesting that new types of stem cells are still being pursued. Sixty percent of the reported stem cell studies involved transplantation, of which over three quarters were allogeneic transplants. A high proportion of the cardiovascular systems articles were on allogeneic transplants in a number of different species, including several autologous studies. A number of pharmaceutical grade stem cell products have also recently been tested and reported on. Stem cell research shows considerable promise for the treatment of a number of disorders, some of which have entered clinical trials; over the next few years it will be interesting to see how these treatments progress in the clinic.

Ageing and neurodegenerative diseases

Ageing, which all creatures must encounter, is a challenge to every living organism. In the human body, it is estimated that cell division and metabolism occurs exuberantly until about 25 years of age. Beyond this age, subsidiary products of metabolism and cell damage accumulate, and the phenotypes of ageing appear, causing disease formation. Among these age-related diseases, neurodegenerative diseases have drawn a lot of attention due to their irreversibility, lack of effective treatment, and accompanied social and economical burdens. In seeking to ameliorate ageing and age-related diseases, the search for anti-ageing drugs has been of much interest. Numerous studies have shown that the plant polyphenol, resveratrol (3,5,4'-trihydroxystilbene), extends the lifespan of several species, prevents age-related diseases, and possesses anti-inflammatory, and anti-cancer properties. The beneficial effects of resveratrol are believed to be associated with the activation of a longevity gene, SirT1. In this review, we discuss the pathogenesis of age-related neurodegenerative diseases including Alzheimer's disease, Parkinson's disease and cerebrovascular disease. The therapeutic potential of resveratrol, diet and the roles of stem cell therapy are discussed to provide a better understanding of the ageing mystery.

Genetic engineering of mesenchymal stem cells and its application in human disease therapy

The use of stem cells for tissue regeneration and repair is advancing both at the bench and bedside. Stem cells isolated from bone marrow are currently being tested for their therapeutic potential in a variety of clinical conditions including cardiovascular injury, kidney failure, cancer, and neurological and bone disorders. Despite the advantages, stem cell therapy is still limited by low survival, engraftment, and homing to damage area as well as inefficiencies in differentiating into fully functional tissues. Genetic engineering of mesenchymal stem cells is being explored as a means to circumvent some of these problems. This review presents the current understanding of the use of genetically engineered mesenchymal stem cells in human disease therapy with emphasis on genetic modifications aimed to improve survival, homing, angiogenesis, and heart function after myocardial infarction. Advancements in other disease areas are also discussed.

Stem cell-based neuroprotective and neurorestorative strategies

Stem cells, a special subset of cells derived from embryo or adult tissues, are known to present the characteristics of self-renewal, multiple lineages of differentiation, high plastic capability, and long-term maintenance. Recent reports have further suggested that neural stem cells (NSCs) derived from the adult hippocampal and subventricular regions possess the utilizing potential to develop the transplantation strategies and to screen the candidate agents for neurogenesis, neuroprotection, and neuroplasticity in neurodegenerative diseases. In this article, we review the roles of NSCs and other stem cells in neuroprotective and neurorestorative therapies for neurological and psychiatric diseases. We show the evidences that NSCs play the key roles involved in the pathogenesis of several neurodegenerative disorders, including depression, stroke and Parkinson’s disease. Moreover, the potential and possible utilities of induced pluripotent stem cells (iPS), reprogramming from adult fibroblasts with ectopic expression of four embryonic genes, are also reviewed and further discussed. An understanding of the biophysiology of stem cells could help us elucidate the pathogenicity and develop new treatments for neurodegenerative disorders. In contrast to cell transplantation therapies, the application of stem cells can further provide a platform for drug discovery and small molecular testing, including Chinese herbal medicines. In addition, the high-throughput stem cell-based systems can be used to elucidate the mechanisms of neuroprotective candidates in translation medical research for neurodegenerative diseases.