Human embryonic germ cell derivatives facilitate motor recovery of rats with diffuse motor neuron injury

New implications for prion diseases therapy and prophylaxis

Prion diseases are rare, fatal, progressive neurodegenerative disorders that affect both animal and human. Human prion diseases mainly present as Creutzfeldt-Jakob disease (CJD). However, there are no curable therapies, and animal prion diseases may negatively affect the ecosystem and human society. Over the past five decades, scientists are devoting to finding available therapeutic or prophylactic agents for prion diseases. Numerous chemical compounds have been shown to be effective in experimental research on prion diseases, but with the limitations of toxicity, poor efficacy, and low pharmacokinetics. The earliest clinical treatments of CJD were almost carried out with anti-infectious agents that had little amelioration of the course. With the discovery of pathogenic misfolding prion protein (PrPSc) and increasing insights into prion biology, amounts of novel technologies have attempted to eliminate PrPSc. This review presents new perspectives on clinical and experimental prion diseases, including immunotherapy, gene therapy, small-molecule drug, and stem cell therapy. It further explores the prospects and challenge associated with these emerging therapeutic approaches for prion diseases.

Regenerative medicine improve neurodegenerative diseases

Regenerative medicine is a subdivision of medicine that improves methods to regrow, repair or replace unhealthy cells and tissues to return to normal function. Cell therapy, gene therapy, nanomedicine as choices used to cure neurodegenerative disease. Recently, studies related to the treatment of neurodegenerative disorders have been focused on stem cell therapy and Nano-drugs beyond other than regenerative medicine. Hence, by data from experimental models and clinical trials, we review the impact of stem cell therapy, gene therapy, and nanomedicine on the treatment of Alzheimer's disease (AD), Parkinson's disease (PD), and Amyotrophic lateral sclerosis (ALS). Indeed, improved knowledge and continued research on gene therapy and nanomedicine in treating Alzheimer's disease, Parkinson's disease, and Amyotrophic lateral sclerosis lead to advancements in effective and practical treatments for neurodegenerative diseases.

Current Advancement of Immunomodulatory Drugs as Potential Pharmacotherapies for Autoimmunity Based Neurological Diseases

Dramatic advancement has been made in recent decades to understand the basis of autoimmunity-mediated neurological diseases. These diseases create a strong influence on the central nervous system (CNS) and the peripheral nervous system (PNS), leading to various clinical manifestations and numerous symptoms. Multiple sclerosis (MS) is the most prevalent autoimmune neurological disease while NMO spectrum disorder (NMOSD) is less common. Furthermore, evidence supports the presence of autoimmune mechanisms contributing to the pathogenesis of amyotrophic lateral sclerosis (ALS), which is a neurodegenerative disorder characterized by the progressive death of motor neurons. Additionally, autoimmunity is believed to be involved in the basis of Alzheimer’s and Parkinson’s diseases. In recent years, the prevalence of autoimmune-based neurological disorders has been elevated and current findings strongly suggest the role of pharmacotherapies in controlling the progression of autoimmune diseases. Therefore, this review focused on the current advancement of immunomodulatory drugs as novel approaches in the management of autoimmune neurological diseases and their future outlook.

Combination therapy with astaxanthin and epidermal neural crest stem cells improves motor impairments and activates mitochondrial biogenesis in a rat model of spinal cord injury

Spinal cord injury (SCI), a multifactorial disease, can lead to irreversible motor and sensory disabilities. Cell therapy in combination with pharmacological agents can be a promising approach to attenuate SCI damages. Epidermal neural crest stem cells (EPI-NCSCs) extracted from bulge hair follicle in adults are attractive candidates due to the possibility of autologous transplantation. This study evaluated the effect of EPI-NCSCs combined with astaxanthin (Ast), a potent antioxidant, on damages induced by SCI. Male rats were treated with Ast (0.2 mM) and EPI-NCSCs (10⁶/10 μl PBS) alone and combined together after SCI contusion. Motor function was assessed by Basso, Beattie and Bresnahan (BBB) test on days 1, 3, 7, 14, 21, 28, 35 and 42 post-injury. Motor neurons number and myelin level were evaluated on days 14 and 42 using Nissl and Luxol Fast Blue staining. The gene expression of mitochondrial biogenesis involved factors (PGC1α, NRF1 and TFAM) was measured by qPCR. All treatments improved motor function, with the highest BBB score in Ast + Cell compared to Ast and Cell. Decreased motor neurons number and myelin level following SCI, were increased by Ast, Cell and Ast + Cell, but combination therapy significantly had a better effect. We observed reduction in PGC1α, NRF1, and TFAM expression in spinal tissue after SCI, and treatment with Cell and Ast + Cell significantly restored NRF1 and TFAM mRNA levels. These results suggested that Ast in combination with EPI-NCSCs has better effects on behavioral dysfunction, motor neuron loss and demyelination after SCI. These protective effects may be attributed to mitochondrial biogenesis activation.

Non-invasive MRI quantification of cerebrospinal fluid dynamics in amyotrophic lateral sclerosis patients

Background

Developing novel therapeutic agents to treat amyotrophic lateral sclerosis (ALS) has been difficult due to multifactorial pathophysiologic processes at work. Intrathecal drug administration shows promise due to close proximity of cerebrospinal fluid (CSF) to affected tissues. Development of effective intrathecal pharmaceuticals will rely on accurate models of how drugs are dispersed in the CSF. Therefore, a method to quantify these dynamics and a characterization of differences across disease states is needed.

Methods

Complete intrathecal 3D CSF geometry and CSF flow velocities at six axial locations in the spinal canal were collected by T2-weighted and phase-contrast MRI, respectively. Scans were completed for eight people with ALS and ten healthy controls. Manual segmentation of the spinal subarachnoid space was performed and coupled with an interpolated model of CSF flow within the spinal canal. Geometric and hydrodynamic parameters were then generated at 1 mm slice intervals along the entire spine. Temporal analysis of the waveform spectral content and feature points was also completed.

Results

Comparison of ALS and control groups revealed a reduction in CSF flow magnitude and increased flow propagation velocities in the ALS cohort. Other differences in spectral harmonic content and geometric comparisons may support an overall decrease in intrathecal compliance in the ALS group. Notably, there was a high degree of variability between cases, with one ALS patient displaying nearly zero CSF flow along the entire spinal canal.

Conclusion

While our sample size limits statistical confidence about the differences observed in this study, it was possible to measure and quantify inter-individual and cohort variability in a non-invasive manner. Our study also shows the potential for MRI based measurements of CSF geometry and flow to provide information about  the hydrodynamic environment of the spinal subarachnoid space. These dynamics may be studied further to understand the behavior of CSF solute transport in healthy and diseased states.

Nanoparticle technology and stem cell therapy team up against neurodegenerative disorders

The convergence of nanoparticles and stem cell therapy holds great promise for the study, diagnosis, and treatment of neurodegenerative disorders. Researchers aim to harness the power of nanoparticles to regulate cellular microenvironment, improve the efficiency of cell and drug delivery to the brain, and enhance the survival of stem cell transplants. Understanding the various properties of different nanoparticles is key to applying them to clinical therapies; the many distinct types of nanoparticles offer unique capacities for medical imaging, diagnosis, and treatment of neurodegeneration disorders. In this review we introduce the biology of Alzheimer's, Parkinson's Disease, and amyotrophic lateral sclerosis, and discuss the potentials and shortcomings of metal, silica, lipid-based, polymeric, and hydrogel nanoparticles for diagnosis and treatment of neurodegenerative disorders. We then provide an overview of current strategies in stem cell therapies and how they can be combined with nanotechnology to improve clinical outcomes.

Targeting RNA helicase DDX3 in stem cell maintenance and teratoma formation

DDX3 is an RNA helicase that has antiapoptotic properties, and promotes proliferation and transformation. Besides the role of DDX3 in transformed cells, there is evidence to indicate that DDX3 expression is at its highest levels during early embryonic development and is also expressed in germ cells of adults. Even though there is a distinct pattern of DDX3 expression during embryonic development and in adults, very little is known regarding its role in embryonic stem cells and pluripotency. In this work, we examined the relationship between DDX3 and human embryonic stem cells and its differentiated lineages. DDX3 expression was analyzed by immunohistochemistry in human embryonic stem cells and embryonal carcinoma cells. From the data obtained, it was evident that DDX3 was overexpressed in undifferentiated stem cells compared to differentiated cells. Moreover, when DDX3 expression was abrogated in multiple stem cells, proliferation was decreased, but differentiation was facilitated. Importantly, this resulted in reduced potency to induce teratoma formation. Taken together, these findings indicate a distinct role for DDX3 in stem cell maintenance.

Quantification of motor neuron loss and muscular atrophy in ricin-induced focal nerve injury

BACKGROUND

Intrasciatic nerve injection of the Ricinus communis agglutinin (RCA or ricin) causes degeneration of motor neurons (MNs) with functional deficits, such as those that occur in amyotrophic lateral sclerosis (ALS). The objective of this study was to develop a new comprehensive platform for quantitative evaluation of MN loss, muscular atrophy and behavioral deficits using different ricin injection regimens.

NEW METHOD

Fluorogold (FG)-guided stereological quantification of MNs, in vivo magnetic resonance imaging (MRI) of muscular atrophy, and CatWalk behavioral testing were used to evaluate the outcome of rats treated with different ricin regimens (RCA60 0.5 μg, RCA60 3 μg, and RCA120 6 μg) as animal models of MN degeneration.

RESULTS

FG-guided stereological counting of MNs enabled identification, dissection and robust quantification of ricin-induced MN loss. The RCA60 0.5 μg and RCA120 6 μg regimens were found to be best suited as preclinical MN depletion models, with a low mortality and a reproducible MN loss, accompanied by muscle atrophy and functional deficits evaluated by MRI and the CatWalk method, respectively.

COMPARISON WITH EXISTING METHODS

1) Fluorogold neuronal tracing provides a robust and straightforward means for quantifying MN loss in the spinal cord; 2) MRI is well-suited to non-invasively assess muscle atrophy; and 3) The CatWalk method is more flexible than rotarod test for studying motor deficits.

CONCLUSION

Intrasciatic injection of RCA60 or RCA120 induces nerve injury and muscle atrophy, which can be properly evaluated by a comprehensive platform using FG-guided quantitative 3D topographic histological analysis, MRI and the CatWalk behavioral test.

On the Viability and Potential Value of Stem Cells for Repair and Treatment of Central Neurotrauma: Overview and Speculations

Central neurotrauma, such as spinal cord injury or traumatic brain injury, can damage critical axonal pathways and neurons and lead to partial to complete loss of neural function that is difficult to address in the mature central nervous system. Improvement and innovation in the development, manufacture, and delivery of stem-cell based therapies, as well as the continued exploration of newer forms of stem cells, have allowed the professional and public spheres to resolve technical and ethical questions that previously hindered stem cell research for central nervous system injury. Recent in vitro and in vivo models have demonstrated the potential that reprogrammed autologous stem cells, in particular, have to restore functionality and induce regeneration-while potentially mitigating technical issues of immunogenicity, rejection, and ethical issues of embryonic derivation. These newer stem-cell based approaches are not, however, without concerns and problems of safety, efficacy, use and distribution. This review is an assessment of the current state of the science, the potential solutions that have been and are currently being explored, and the problems and questions that arise from what appears to be a promising way forward (i.e., autologous stem cell-based therapies)-for the purpose of advancing the research for much-needed therapeutic interventions for central neurotrauma.

Intrathecal Autologous Bone Marrow-Derived Hematopoietic Stem Cell Therapy in Neurological Diseases

BACKGROUND

Cellular transplantation is a promising treatment strategy for neurological diseases.

OBJECTIVE

To report the results of intrathecal hematopoietic stem cell therapy in different neurological diseases in the past 6 years in a single center.

METHODS

From October 2011 to September 2018, 220 patients with various neurological diseases were transplanted intrathecally by their bone marrow stem cells. To have a longer follow up, we only reported the first 80 patients, transplanted up to July 2015-10 patients had spinal cord injuries and paralysis, 12 had advanced Parkinson's disease, 28 had cerebral palsy, 7 had hypoxic brain damage, 2 had autism, 4 had multiple sclerosis, 5 had progressive cerebellar atrophy, and 12 had other neurological diseases. The patients were admitted to the Bone Marrow Transplant Unit. On the first day, 50-200 (median 100) mL bone marrow was aspirated from the patients' posterior iliac crests, mixed with 120 mL culture media (RPMI), and 12 mL heparin. The samples were then transferred to immunology lab in cold box. Mononuclear cells (MNCs) were separated by a Ficoll-Hypaque gradient, washed, and suspended in ringers. Cell viability was assessed with trypan blue viability test. Transplantation was performed 3-4 hours after bone marrow collection. 5-10 mL of the cerebrospinal fluids were aspirated and about 20 mL MNCs (containing stem cells) in ringers were injected intrathecally (IT). The patients were laid down on their back for 4-5 hours. The median number of MNCs was 4×10⁷ (range 1-450×10⁷). The median viability of the cells was 90% (range 60%-98%). The patients received intravenous ceftriaxone every 12 hours and were discharged from the hospital few days after autologous stem cell therapy.

RESULTS

We noted clinical improvements in 9 of 12 patients with Parkinson's disease, 20 of 28 patients with cerebral palsy, 6 of 7 patients with hypoxic brain damage, 2 of 4 patients with multiple sclerosis, and 4 of 5 patients with cerebellar atrophy. The improvements were noted after 2-4 weeks of cell therapy. There were no improvements in patients with spinal cord injury and complete paralysis and those with autism. There were variable improvements in other patients treated.

CONCLUSION

Most patients with advanced Parkinson's disease, cerebral palsy, hypoxic brain damage, progressive cerebellar atrophy, and kernicterus neuropathy reported clinical effects of this safe intervention resulting in better functioning and an increased quality of life.

Myelin Basic Protein Regulates Primitive and Definitive Neural Stem Cell Proliferation from the Adult Spinal Cord

The adult mammalian forebrain comprises two distinct populations of neural stem cells (NSCs): rare, Oct4 positive, primitive NSCs (pNSCs) and definitive NSC (dNSC) which are more abundant and express GFAP. The pNSCs are upstream of the dNSCs in the neural stem cell lineage. Herein we show that pNSC and dNSC populations can also be isolated from the developing and adult spinal cord. Spinal cord derived pNSCs are similarly rare, Oct4 expressing cells that are responsive to leukemia inhibitory factor and dNSCs are 4-5X more abundant and express GFAP. We demonstrate that myelin basic protein (MBP) is inhibitory to both pNSC and dNSC derived colony formation. Similar to what is seen in the adult forebrain following injury, spinal cord injury results in a significant increase in the size of the dNSC and pNSC pools. Hence, both primitive and definitive neural stem cells can be isolated from along the embryonic and adult neuraxis in vivo and their behavior is regulated by MBP and injury. Stem Cells 2017;35:485-496.

Human Embryonic Stem Cell Therapy in Chronic Spinal Cord Injury: A Retrospective Study

Human embryonic stem cells (hESCs) have a role in treating neurological disorders. The efficacy and safety of hESC in treating spinal cord injury (SCI) was reported in our previous study. In the present study, we have evaluated the efficacy and safety of hESC therapy in 226 patients with SCI. In the first treatment phase (T1), 0.25 mL hESCs were administered intramuscularly twice daily, 1 mL every 10 days i.v., and 1-5 mL every 7 days. Of 153 patients in the American Spinal Injury Association (ASIA) scale A at the beginning of T1, a significant number of patients (n = 80; 52.3%) moved to lower scales at the end of T1 (p = 0.01). At the end of T2, of 32 patients in ASIA scale A, 12 patients (37.5%) moved to scale B (p = 0.01). Of 19 patients, 3 patients (37.5%) moved to scale B at the end of T3 (p = 0.02). No serious adverse events (AEs) were observed. hESC transplantation is safe and effective.

Transplantation of neural stem cells clonally derived from embryonic stem cells promotes recovery after murine spinal cord injury

The pathology of spinal cord injury (SCI) makes it appropriate for cell-based therapies. Treatments using neural stem cells (NSCs) in animal models of SCI have shown positive outcomes, although uncertainty remains regarding the optimal cell source. Pluripotent cell sources such as embryonic stem cells (ESCs) provide a limitless supply of therapeutic cells. NSCs derived using embryoid bodies (EB) from ESCs have shown tumorigenic potential. Clonal neurosphere generation is an alternative method to generate safer and more clinically relevant NSCs without the use of an EB stage for use in cell-based therapies. We generated clonally derived definitive NSCs (dNSCs) from ESC. These cells were transplanted into a mouse thoracic SCI model. Embryonic stem cell-derived definitive neural stem cell (ES-dNSC)-transplanted mice were compared with controls using behavioral measures and histopathological analysis of tissue. In addition, the role of remyelination in injury recovery was investigated using transmission electron microscopy. The SCI group that received ES-dNSC transplantation showed significant improvements in locomotor function compared with controls in open field and gait analysis. The cell treatment group had a significant enhancement of spared neural tissue. Immunohistological assessments showed that dNSCs differentiated primarily to oligodendrocytes. These cells were shown to express myelin basic protein, associate with axons, and support nodal architecture as well as display proper compact, multilayer myelination in electron microscopic analysis. This study provides strong evidence that dNSCs clonally derived from pluripotent cells using the default pathway of neuralization improve motor function after SCI and enhance sparing of neural tissue, while remaining safe and clinically relevant.

Recent Advances and the Future of Stem Cell Therapies in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis is a progressive neurodegenerative disease of the motor neurons without a known cure. Based on the possibility of cellular neuroprotection and early preclinical results, stem cells have gained widespread enthusiasm as a potential treatment strategy. Preclinical models demonstrate a protective role of engrafted stem cells and provided the basis for human trials carried out using various types of stem cells, as well as a range of cell delivery methods. To date, no trial has demonstrated a clear therapeutic benefit; however, results remain encouraging and are the basis for ongoing studies. In addition, stem cell technology continues to improve, and induced pluripotent stem cells may offer additional therapeutic options in the future. Improved disease models and clinical trials will be essential in order to validate stem cells as a beneficial therapy.

Early intervention for spinal cord injury with human induced pluripotent stem cells oligodendrocyte progenitors

Induced pluripotent stem (iPS) cells are at the forefront of research in regenerative medicine and are envisaged as a source for personalized tissue repair and cell replacement therapy. Here, we demonstrate for the first time that oligodendrocyte progenitors (OPs) can be derived from iPS cells generated using either an episomal, non-integrating plasmid approach or standard integrating retroviruses that survive and differentiate into mature oligodendrocytes after early transplantation into the injured spinal cord. The efficiency of OP differentiation in all 3 lines tested ranged from 40% to 60% of total cells, comparable to those derived from human embryonic stem cells. iPS cell lines derived using episomal vectors or retroviruses generated a similar number of early neural progenitors and glial progenitors while the episomal plasmid-derived iPS line generated more OPs expressing late markers O1 and RIP. Moreover, we discovered that iPS-derived OPs (iPS-OPs) engrafted 24 hours following a moderate contusive spinal cord injury (SCI) in rats survived for approximately two months and that more than 70% of the transplanted cells differentiated into mature oligodendrocytes that expressed myelin associated proteins. Transplanted OPs resulted in a significant increase in the number of myelinated axons in animals that received a transplantation 24 h after injury. In addition, nearly a 5-fold reduction in cavity size and reduced glial scarring was seen in iPS-treated groups compared to the control group, which was injected with heat-killed iPS-OPs. Although further investigation is needed to understand the mechanisms involved, these results provide evidence that patient-specific, iPS-derived OPs can survive for three months and improve behavioral assessment (BBB) after acute transplantation into SCI. This is significant as determining the time in which stem cells are injected after SCI may influence their survival and differentiation capacity.

Differentiation of neurons restricts Arbovirus replication and increases expression of the alpha isoform of IRF-7

Susceptibility to alphavirus infection is age dependent, and host maturation is associated with decreased virus replication and less severe encephalitis. To identify factors associated with maturation-dependent restriction of virus replication, we studied AP-7 rat olfactory bulb neuronal cells, which can differentiate in vitro. Differentiation was associated with a 150- to 1,000-fold decrease in replication of the alphaviruses Sindbis virus and Venezuelan equine encephalitis virus, as well as La Crosse bunyavirus. Differentiation delayed synthesis of SINV RNA and protein but did not alter the susceptibility of neurons to infection or virion maturation. Additionally, differentiation slowed virus-induced translation arrest and death of infected cells. Differentiation of uninfected AP-7 neurons was associated with changes in expression of antiviral genes. Expression of key transcription factors was increased, including interferon regulatory factor 3 and 7 (IRF-3 and IRF-7) and STAT-1, suggesting that neuronal maturation may enhance the capacity for antiviral signaling upon infection. IRF-7 produced by undifferentiated AP-7 neurons was exclusively the short dominant negative γ-isoform, while that produced by differentiated neurons was the full-length α-isoform. A similar switch in IRF-7 isoforms also occurred in the brains of maturing C57BL/6J mice. Silencing of IRF expression did not improve virus multiplication in differentiated neurons. Therefore, neuronal differentiation is associated with upregulation of transcription factors that activate antiviral signaling, but this alone does not account for maturation-dependent restriction of virus replication.

IMPORTANCE

Viral encephalomyelitis is an important cause of age-dependent morbidity and mortality. Because mature neurons are not readily regenerated, recovery from encephalitis suggests that mature neurons utilize unique antiviral mechanisms to block infection and/or clear virus. To identify maturational changes in neurons that may improve outcome, we compared immature and mature cultured neurons for susceptibility to three encephalitic arboviruses and found that replication of Old World and New World alphaviruses and a bunyavirus was reduced in mature compared to immature neurons. Neuronal maturation was associated with increased baseline expression of interferon regulatory factor 3 and 7 mRNAs and production of distinct isoforms of interferon regulatory factor 7 protein. Overall, our studies identified maturational changes in neurons that likely contribute to assembly of immunoregulatory factors prior to infection, a more rapid antiviral response, increased resistance to virus infection, and improved survival.

Stem cell transplantation for amyotrophic lateral sclerosis: therapeutic potential and perspectives on clinical translation

Amyotrophic lateral sclerosis (ALS) is a fatal neurological disease characterized by degeneration of upper and lower motor neurons. There are currently no clinically impactful treatments for this disorder. Death occurs 3-5 years after diagnosis, usually due to respiratory failure. ALS pathogenesis seems to involve several pathological mechanisms (i.e., oxidative stress, inflammation, and loss of the glial neurotrophic support, glutamate toxicity) with different contributions from environmental and genetic factors. This multifaceted combination highlights the concept that an effective therapeutic approach should counteract simultaneously different aspects: stem cell therapies are able to maintain or rescue motor neuron function and modulate toxicity in the central nervous system (CNS) at the same time, eventually representing the most comprehensive therapeutic approach for ALS. To achieve an effective cell-mediated therapy suitable for clinical applications, several issues must be addressed, including the identification of the most performing cell source, a feasible administration protocol, and the definition of therapeutic mechanisms. The method of cell delivery represents a major issue in developing cell-mediated approaches since the cells, to be effective, need to be spread across the CNS, targeting both lower and upper motor neurons. On the other hand, there is the need to define a strategy that could provide a whole distribution without being too invasive or burdened by side effects. Here, we review the recent advances regarding the therapeutic potential of stem cells for ALS with a focus on the minimally invasive strategies that could facilitate an extensive translation to their clinical application.

Human motor neurons generated from neural stem cells delay clinical onset and prolong life in ALS mouse model

Amyotrophic lateral sclerosis (ALS) is the most common adult onset motor neuron disease. The etiology and pathogenic mechanisms of the disease remain unknown, and there is no effective treatment. Here we show that intrathecal transplantation of human motor neurons derived from neural stem cells (NSCs) in spinal cord of the SOD1G93A mouse ALS model delayed disease onset and extended life span of the animals. When HB1.F3.Olig2 (F3.Olig2) cells, stable immortalized human NSCs encoding the human Olig2 gene, were treated with sonic hedgehog (Shh) protein for 5–7 days, the cells expressed motor neuron cell type-specific phenotypes Hb9, Isl-1 and choline acetyltransferase (ChAT). These F3.Olig2-Shh human motor neurons were transplanted intrathecally in L5–L6 spinal cord of SOD1G93A mice, and at 4 weeks post-transplantation, transplanted F3.Olig2-Shh motor neurons expressing the neuronal phenotype markers NF, MAP2, Hb9, and ChAT were found in the ventral horn of the spinal cord. Onset of clinical signs in ALS mice with F3.Olig2-Shh motor neuron implants was delayed for 7 days and life span of animals was significantly extended by 20 days. Our results indicate that this treatment modality of intrathecal transplantation of human motor neurons derived from NSCs might be of value in the treatment of ALS patients without significant adverse effects.

Transplantation of Stem Cells Obtained from Murine Dental Pulp Improves Pancreatic Damage, Renal Function, and Painful Diabetic Neuropathy in Diabetic Type 1 Mouse Model

Diabetes mellitus (DM) is one of the most common and serious chronic diseases in the world. Here, we investigated the effects of mouse dental pulp stem cell (mDPSC) transplantation in a streptozotocin (STZ)-induced diabetes type 1 model. C57BL/6 mice were treated intraperitoneally with 80 mg/kg of STZ and transplanted with 1 × 106 mDPSCs or injected with saline, by an endovenous route, after diabetes onset. Blood and urine glucose levels were reduced in hyperglycemic mice treated with mDPSCs when compared to saline-treated controls. This correlated with an increase in pancreatic islets and insulin production 30 days after mDPSC therapy. Moreover, urea and proteinuria levels normalized after mDPSC transplantation in diabetic mice, indicating an improvement of renal function. This was confirmed by a histopathological analysis of kidney sections. We observed the loss of the epithelial brush border and proximal tubule dilatation only in saline-treated diabetic mice, which is indicative of acute renal lesion. STZ-induced thermal hyperalgesia was also reduced after cell therapy. Three days after transplantation, mDPSC-treated diabetic mice exhibited nociceptive thresholds similar to that of nondiabetic mice, an effect maintained throughout the 90-day evaluation period. Immunofluorescence analyses of the pancreas revealed the presence of GFP+ cells in, or surrounding, pancreatic islets. Our results demonstrate that mDPSCs may contribute to pancreatic β-cell renewal, prevent renal damage in diabetic animals, and produce a powerful and long-lasting antinociceptive effect on behavioral neuropathic pain. Our results suggest stem cell therapy as an option for the control of diabetes complications such as intractable diabetic neuropathic pain.

Transplantation of mesenchymal stem cells in ALS

Amyotrophic lateral sclerosis (ALS) is a devastating incurable, neurodegenerative disease that targets motor neurons (MNs) in the primary motor cortex, brainstem, and spinal cord, leading to muscle atrophy, paralysis, and death due to respiratory failure within 2-5 years. Currently, there is no cure for ALS. The development of a therapy that can support or restore MN function and attenuate toxicity in the spinal cord provides the most comprehensive approach for treating ALS. Mesenchymal stem cells might be suitable for cell therapy in ALS because of their immunomodulatory and protective properties. In this review, the authors discuss the major challenges to the translation of in vitro and animal studies of MSCs therapy in the clinical setting.

Transplantation of human adipose tissue-derived stem cells delays clinical onset and prolongs life span in ALS mouse model

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that selectively affects motor neurons in the cortex, brain stem, and spinal cord. The precise pathogenic mechanism remains unknown, and there is currently no effective therapy. We evaluated the therapeutic effects of human adipose tissue-derived stem cells (ASCs) in an animal model of ALS. Human abdominal subcutaneous fat tissues were obtained by simple liposuction from donors, and ASCs were isolated from the fat stromal vascular fraction. ASCs were found to differentiate into adipocytes, chondrocytes, osteocytes, and neurons. SOD1G93A ALS mice were divided into three groups: sham, intravenous (IV), and intracerebroventricular (ICV) groups. Human ASCs were transplanted in the ALS mice at 70 postnatal days before the appearance of clinical symptoms. Behavior of transplanted animals was assessed by rotarod test, paw grip endurance (PaGE), and reflex index. Mice in every group were sacrificed after 4 weeks posttransplantation. Transplanted ASCs were identified in the lumbar spinal cords with an antihuman mitochondria antibody and cell type-specific markers for neurons or astrocytes. Delayed onset of clinical symptoms (26 days) and extended survival of animals (24 days) were observed in ALS mice transplanted with ASCs via ICV route. ASCs were found to secrete high levels of neurotrophic factors such as NGF, BDNF, IGF-1, and VEGF. Reduction of apoptotic cell death by these factors was confirmed in cultured CNS cells and in the ALS spinal cord. These results indicate that transplantation of ASCs in ALS mice provides neuroprotective effects by production of cytokines/growth factors, delays disease progression, and prolongs the life span of ALS mice.

Human marrow stromal cells reduce microglial activation to protect motor neurons in a transgenic mouse model of amyotrophic lateral sclerosis

Background

Human marrow stromal cells (hMSCs) injected intrathecally can effectively increase the lifespan and protect motor neurons in a transgenic mouse model of amyotrophic lateral sclerosis. However, how the transplanted cells exert a neuroprotective effect is still unclear. More recently, the anti-inflammation effect of marrow stromal cells has generated a great deal of interest. In the present study, we sought to investigate whether intrathecally injected hMSCs protect motor neurons through attenuating microglial activation and the secretion of inflammatory factors in Cu/Zn superoxide dismutase 1 (SOD1) transgenic mice. In addition, we also focused on the mode of hMSCs inhibiting microglial activation.

Methods

We transplanted hMSCs into the cisterna magna of SOD1 mice at the age of 8, 10 and 12 weeks. At sacrifice, tissues were harvested for analysis of neuron counts, microglial activation, TNFα secretion and inducible nitric oxide synthase (iNOS) protein expression. In vitro, microglial cells were treated with hMSC co-culture, hMSC transwell culture or hMSC conditioned medium to investigate the mode of hMSCs exerting an anti-inflammation effect.

Results

Intrathecally transplanted hMSCs inhibited inflammatory response in SOD1 transgenic mice, which was evidenced by the decreases in microglial activation, TNFα secretion and iNOS protein expression. In addition, the inhibitory effect on microglial activation of hMSCs was through secretion of diffusible molecules adjusted to environmental cues.

Conclusion

Intrathecally injected hMSCs can attenuate microglial activation through secretion of diffusible molecules to exert a therapeutic effect in SOD1 transgenic mice. Further studies are needed to explore the exact mechanisms by which hMSCs inhibit inflammation for facilitating the therapeutic effect.

Neural stem cell-based treatment for neurodegenerative diseases

Human neurodegenerative diseases such as Parkinson's disease (PD), Huntington's disease (HD), amyotrophic lateral sclerosis (ALS) and Alzheimer's disease (AD) are caused by a loss of neurons and glia in the brain or spinal cord. Neurons and glial cells have successfully been generated from stem cells such as embryonic stem cells (ESCs), mesenchymal stem cells (MSCs) and neural stem cells (NSCs), and stem cell-based cell therapies for neurodegenerative diseases have been developed. A recent advance in generation of a new class of pluripotent stem cells, induced pluripotent stem cells (iPSCs), derived from patients' own skin fibroblasts, opens doors for a totally new field of personalized medicine. Transplantation of NSCs, neurons or glia generated from stem cells in animal models of neurodegenerative diseases, including PD, HD, ALS and AD, demonstrates clinical improvement and also life extension of these animals. Additional therapeutic benefits in these animals can be provided by stem cell-mediated gene transfer of therapeutic genes such as neurotrophic factors and enzymes. Although further research is still needed, cell and gene therapy based on stem cells, particularly using neurons and glia derived from iPSCs, ESCs or NSCs, will become a routine treatment for patients suffering from neurodegenerative diseases and also stroke and spinal cord injury.

Properties of mechano-transduction via simulated microgravity and its effects on intracellular trafficking of VEGFR's

This study emphasizes the dynamical properties of mechanical loading via simulated microgravity, its effect on acute myeloid leukemia proliferation and hematopoietic stem cell (HSPC) growth and its implications in the area of tissue regeneration. Data presented illustrates that mechanical transduction changes the expression of humoral factors by facilitating paracrine/autocrine signalling, therefore modulating intracellular trafficking of tyrosine kinase receptors. Understanding mechano-transduction in the context of cell and tissue morphogenesis is the major focus of this study. The effects of external physiological stresses, such as blood flow, on several cellular subtypes seem to produce very intricate cellular responses. It is well accepted that mechanical loading plays an intrinsic and extrinsic influence on cell survival. This study shows how microgravity effects hematopoietic stem cells, and human leukemic cell proliferation and expression of its receptors that control cell survival, such as the tyrosine kinase vascular endothelial growth factor receptor-1, receptor-2 and receptor-3.

Olfactory ensheathing cell neurorestorotherapy for amyotrophic lateral sclerosis patients: benefits from multiple transplantations

Our previous series of studies have proven that olfactory ensheathing cell (OEC) transplantation appears to be able to slow the rate of clinical progression after OEC transplantation in the first 4 months and cell intracranial (key points for neural network restoration, KPNNR) and/or intraspinal (impaired segments) implants provide benefit for patients (including both the bulbar onset and limb onset subtypes) with amyotrophic lateral sclerosis (ALS). Here we report the results of cell therapy in patients with ALS on the basis of long-term observation following multiple transplants. From March of 2003 to January of 2010, 507 ALS patients received our cellular treatment. Among them, 42 patients underwent further OEC therapy by the route of KPNNR for two or more times (two times in 35 patients, three times in 5 patients, four times in 1 patient, and five times in 1 patient). The time intervals are 13.1 (6-60) months between the first therapy and the second one, 15.2 (8-24) months between the second therapy and the third one, 16 (6-26) months between the third therapy and the fourth one, and 9 months between the fourth therapy and the fifth time. All of the patients exhibited partial neurological functional recovery after each cell-based administration. Firstly, the scores of the ALS Functional Rating Scale (ALS-FRS) and ALS Norris Scale increased by 2.6 + 2.4 (0-8) and 4.9 + 5.2 (0-20) after the first treatment, 1.1 + 1.3 (0-5) and 2.3 + 2.9 (0-13) after the second treatment, 1.1 + 1.5 (0-4), and 3.4 + 6.9 (0-19) after the third treatment, 0.0 + 0.0 (0-0), and 2.5 + 3.5 (0-5) after the fourth treatment, and 1 point after the fifth cellular therapy, which were evaluated by independent neurologists. Secondly, the majority of patients have achieved improvement in electromyogram (EMG) assessments after the first, second, third, and fourth cell transplantation. After the first treatment, among the 42 patients, 36 (85.7%) patients' EMG test results improved, the remaining 6 (14.3%) patients' EMG results showed no remarkable change. After the second treatment, of the 42 patients, 30 (71.4%) patients' EMG results improved, 11 (26.2%) patients showed no remarkable change, and 1 (2.4%) patient became worse. After the third treatment, out of the 7 patients, 4 (57.1%) patients improved, while the remaining 3 (42.9%) patients showed no change. Thirdly, the patients have partially recovered their breathing ability as demonstrated by pulmonary functional tests. After the first treatment, 20 (47.6%) patients' pulmonary function ameliorated. After the second treatment, 18 (42.9%) patients' pulmonary function improved. After the third treatment, 2 (28.6%) patients recovered some pulmonary function. After the fourth and fifth treatment, patients' pulmonary function did not reveal significant change. The results show that multiple doses of cellular therapy definitely serve as a positive role in the treatment of ALS. This repeated and periodic cell-based therapy is strongly recommended for the patients, for better controlling this progressive deterioration disorder.

[Stem cell-based treatment of neurologic diseases]

Therapeutic strategies based on stem cells are being increasingly used to treat a wide range of neurological diseases. Although these strategies were initially designed to replace dead cells in injured tissue, the potential of stem cells to migrate, secrete trophic factors, and immunomodulate allows their therapeutic use as a vehicle for gene therapy, as in Parkinson's disease, or as immunomodulators and neuroprotectors in diseases such as multiple sclerosis. This review will focus on current clinical and experimental evidence on the treatment of neurological disorders with strategies based on stem cells.

Cotransplantation of Human Embryonic Stem Cell-Derived Neural Progenitors and Schwann Cells in a Rat Spinal Cord Contusion Injury Model Elicits a Distinct Neurogenesis and Functional Recovery

Cotransplantation of neural progenitors (NPs) with Schwann cells (SCs) might be a way to overcome low rate of neuronal differentiation of NPs following transplantation in spinal cord injury (SCI) and the improvement of locomotor recovery. In this study, we initially generated NPs from human embryonic stem cells (hESCs) and investigated their potential for neuronal differentiation and functional recovery when cocultured with SCs in vitro and cotransplanted in a rat acute model of contused SCI. Cocultivation results revealed that the presence of SCs provided a consistent status for hESC-NPs and recharged their neural differentiation toward a predominantly neuronal fate. Following transplantation, a significant functional recovery was observed in all engrafted groups (NPs, SCs, NPs + SCs) relative to the vehicle and control groups. We also observed that animals receiving cotransplants established a better state as assessed with the BBB functional test. Immunohistofluorescence evaluation 5 weeks after transplantation showed invigorated neuronal differentiation and limited proliferation in the cotransplanted group when compared to the individual hESC-NP-grafted group. These findings have demonstrated that the cotransplantation of SCs with hESC-NPs could offer a synergistic effect, promoting neuronal differentiation and functional recovery.

A comparison between neurally induced bone marrow derived mesenchymal stem cells and olfactory ensheathing glial cells to repair spinal cord injuries in rat

Cell therapy has proven to be a highly promising method in clinical applications, raising so much hope for the treatment of injured tissues with low, if any, self regeneration potential such as central and peripheral nervous system. Neurally induced bone marrow derived mesenchymal stem cells (NIMSCs) as well as olfactory ensheathing cells (OECs) were transplanted in a rat model of sub-acute spinal cord injury and the behavioral and histological analyses were conducted. A balloon-compression technique was used to produce an injury at T8-T9 level of spinal cord. After a week post injury, rats were injected with either NIMSCs or OECs at the center of developing lesion cavity, 3mm cranial and 3mm caudal to the cavity. Weekly behavioral assessment using BBB score was done over five-week period post transplantation and finally histological assessment was performed to locate labeled cells in the tissue in order to evaluate the reduction of cavity formation and axonal regeneration. Evaluation of locomotor performance showed significant behavioral improvement in NIMSC group over OEC and control groups. The histological analyses revealed the presence of transplanted cells in the spinal cord parenchyma. Volume of injured area that was occupied with syrinx cavity in NIMSC group was significantly less than control group. In addition, meanwhile neurofilament-positive axons significantly showed higher expression in rats receiving NIMSC compared to the other two groups. In conclusion NIMSC caused both behavioral and histological improvement that potentially makes them a promising candidate for cell therapy approaches of spinal cord injuries.

Molecular imaging for stem cell transplantation in neuroregenerative medicine

Stem cell transplantation is a promising new therapeutic option in different neurological diseases. However, it was not yet possible to translate its potential from animal models to clinical application. One of the main problems of applying stem cell transplantation in clinical medium is the difficulty of detection, localization, and examination of the stem cells in vivo at both cellular and molecular levels. State-of-the-art molecular imaging techniques provide new and better means for noninvasive, repeated, and quantitative tracking of stem cell implant or transplant. From initial deposition to the survival, migration, and differentiation of the transplant/implanted stem cells, current molecular imaging methods allow monitoring of the infused cells in the same live recipient over time. The present review briefly summarizes and compares these molecular imaging methods for cell labeling and imaging in animal models as well as in clinical application and sheds light on consecutive new therapeutic options if appropriate.

Achieving stable human stem cell engraftment and survival in the CNS: is the future of regenerative medicine immunodeficient?

There is potential for a variety of stem cell populations to mediate repair in the diseased or injured CNS; in some cases, this theoretical possibility has already transitioned to clinical safety testing. However, careful consideration of preclinical animal models is essential to provide an appropriate assessment of stem cell safety and efficacy, as well as the basic biological mechanisms of stem cell action. This article examines the lessons learned from early tissue, organ and hematopoietic grafting, the early assumptions of the stem cell and CNS fields with regard to immunoprivilege, and the history of success in stem cell transplantation into the CNS. Finally, we discuss strategies in the selection of animal models to maximize the predictive validity of preclinical safety and efficacy studies.

Cell therapy for multiple sclerosis

The spontaneous recovery observed in the early stages of multiple sclerosis (MS) is substituted with a later progressive course and failure of endogenous processes of repair and remyelination. Although this is the basic rationale for cell therapy, it is not clear yet to what degree the MS brain is amenable for repair and whether cell therapy has an advantage in comparison to other strategies to enhance endogenous remyelination. Central to the promise of stem cell therapy is the therapeutic plasticity, by which neural precursors can replace damaged oligodendrocytes and myelin, and also effectively attenuate the autoimmune process in a local, nonsystemic manner to protect brain cells from further injury, as well as facilitate the intrinsic capacity of the brain for recovery. These fundamental immunomodulatory and neurotrophic properties are shared by stem cells of different sources. By using different routes of delivery, cells may target both affected white matter tracts and the perivascular niche where the trafficking of immune cells occur. It is unclear yet whether the therapeutic properties of transplanted cells are maintained with the duration of time. The application of neural stem cell therapy (derived from fetal brain or from human embryonic stem cells) will be realized once their purification, mass generation, and safety are guaranteed. However, previous clinical experience with bone marrow stromal (mesenchymal) stem cells and the relative easy expansion of autologous cells have opened the way to their experimental application in MS. An initial clinical trial has established the probable safety of their intravenous and intrathecal delivery. Short-term follow-up observed immunomodulatory effects and clinical benefit justifying further clinical trials.

Quantitative temporal proteomic analysis of human embryonic stem cell differentiation into oligodendrocyte progenitor cells

Oligodendrocytes (OLs) are glial cells of the central nervous system, which produce myelin. Cultured OLs provide immense therapeutic opportunities for treating a variety of neurological conditions. One of the most promising sources for such therapies is human embryonic stem cells (ESCs) as well as providing a model to study human OL development. For these purposes, an investigation of proteome level changes is critical for understanding the process of OL differentiation. In this report, an iTRAQ-based quantitative proteomic approach was used to study multiple steps during OL differentiation including neural progenitor cells, glial progenitor cells and oligodendrocyte progenitor cells (OPCs) compared to undifferentiated ESCs. Using a 1% false discovery rate cutoff, ∼3145 proteins were quantitated and several demonstrated progressive stage-specific expression. Proteins such as transferrin, neural cell adhesion molecule 1, apolipoprotein E and wingless-related MMTV integration site 5A showed increased expression from the neural progenitor cell to the OPC stage. Several proteins that have demonstrated evidence or been suspected in OL maturation were also found upregulated in OPCs including fatty acid-binding protein 4, THBS1, bone morphogenetic protein 1, CRYAB, transferrin, tenascin C, COL3A1, TGFBI and EPB41L3. Thus, by providing the first extensive proteomic profiling of human ESC differentiation into OPCs, this study provides many novel proteins that are potentially involved in OL development.

Spinal muscular atrophy: advances in research and consensus on care of patients

Spinal muscular atrophy (SMA) is an autosomal recessive disease characterized by degeneration of spinal cord motor neurons and muscular atrophy. Advances in recent research have led to understanding of the molecular genetics of SMA. Therapeutic strategies have been developed according to the unique genomic structure of the SMN genes. Three groups of compounds have been identified as therapeutic candidates. One group was identified before the molecular genetics of SMA was understood, chosen on the basis of their effectiveness in similar neurologic disorders. The second group was identified based on their ability to modify SMN2 gene expression. Several of these agents are currently in clinical trials. A third group, identified by large-scale drug screening, is still under preclinical investigation. In addition, other advances in medical technology have led to the publication of a consensus statement regarding the care of SMA patients.

Emerging treatment options for spinal muscular atrophy

The motor neuron disease spinal muscular atrophy (SMA) is one of the leading genetic killers of infants worldwide. SMA is caused by mutation of the survival motor neuron 1 (SMN1) gene and deficiency of the survival motor neuron (SMN) protein. All patients retain one or more copies of the SMN2 gene, which (by producing a small amount of the SMN protein) rescues embryonic lethality and modifies disease severity. Rapid progress continues in dissecting the cellular functions of the SMN protein, but the mechanisms linking SMN deficiency with dysfunction and loss of functioning motor units remain poorly defined. Clinically, SMA should to be distinguished from other neuromuscular disorders, and the diagnosis can be readily confirmed with genetic testing. Quality of life and survival of SMA patients are improved with aggressive supportive care including optimized respiratory and nutritional care and management of scoliosis and contractures. Because SMA is caused by inadequate amounts of SMN protein, one aim of current SMA therapeutics development is to increase SMN protein levels in SMA patients by activating SMN2 gene expression and/or increasing levels of full-length SMN2 transcripts. Several potential therapeutic compounds are currently being studied in clinical trials in SMA patients.

Modeling spinal muscular atrophy in Drosophila links Smn to FGF signaling

FGF signaling in neurons is regulated by Survival Motor Neuron, a component of a complex that regulates snRNP biogenesis and FGF receptor expression.

Spinal muscular atrophy (SMA), a devastating neurodegenerative disorder characterized by motor neuron loss and muscle atrophy, has been linked to mutations in the Survival Motor Neuron (SMN) gene. Based on an SMA model we developed in Drosophila, which displays features that are analogous to the human pathology and vertebrate SMA models, we functionally linked the fibroblast growth factor (FGF) signaling pathway to the Drosophila homologue of SMN, Smn. Here, we characterize this relationship and demonstrate that Smn activity regulates the expression of FGF signaling components and thus FGF signaling. Furthermore, we show that alterations in FGF signaling activity are able to modify the neuromuscular junction defects caused by loss of Smn function and that muscle-specific activation of FGF is sufficient to rescue Smn-associated abnormalities.

Critical care of traumatic spinal cord injury

Approximately 11 000 people suffer traumatic spinal cord injury (TSCI) in the United States, each year. TSCI incidences vary from 13.1 to 52.2 per million people and the mortality rates ranged from 3.1 to 17.5 per million people. This review examines the critical care of TSCI. The discussion will focus on primary and secondary mechanisms of injury, spine stabilization and immobilization, surgery, intensive care management, airway and respiratory management, cardiovascular complication management, venous thromboembolism, nutrition and glucose control, infection management, pressure ulcers and early rehabilitation, pharmacologic cord protection, and evolving treatment options including the use of pluripotent stem cells and hypothermia.

Embryonic stem cell-derived L1 overexpressing neural aggregates enhance recovery after spinal cord injury in mice

An obstacle to early stem cell transplantation into the acutely injured spinal cord is poor survival of transplanted cells. Transplantation of embryonic stem cells as substrate adherent embryonic stem cell-derived neural aggregates (SENAs) consisting mainly of neurons and radial glial cells has been shown to enhance survival of grafted cells in the injured mouse brain. In the attempt to promote the beneficial function of these SENAs, murine embryonic stem cells constitutively overexpressing the neural cell adhesion molecule L1 which favors axonal growth and survival of grafted and imperiled cells in the inhibitory environment of the adult mammalian central nervous system were differentiated into SENAs and transplanted into the spinal cord three days after compression lesion. Mice transplanted with L1 overexpressing SENAs showed improved locomotor function when compared to mice injected with wild-type SENAs. L1 overexpressing SENAs showed an increased number of surviving cells, enhanced neuronal differentiation and reduced glial differentiation after transplantation when compared to SENAs not engineered to overexpress L1. Furthermore, L1 overexpressing SENAs rescued imperiled host motoneurons and parvalbumin-positive interneurons and increased numbers of catecholaminergic nerve fibers distal to the lesion. In addition to encouraging the use of embryonic stem cells for early therapy after spinal cord injury L1 overexpression in the microenvironment of the lesioned spinal cord is a novel finding in its functions that would make it more attractive for pre-clinical studies in spinal cord regeneration and most likely other diseases of the nervous system.

Development of complete thoracic spinal cord transection model in rats for delayed transplantation of stem cells

STUDY DESIGN

In vivo study of a rat spinal cord injury model.

OBJECTIVES

To develop complete transection model of thoracic spinal cord using a polymer sheet and a microtube relevant for delayed transplantation of stem cells.

SUMMARY OF BACKGROUND DATA

Stem cell transplantation for the regeneration of spinal cord injuries has used animal models. However, current models suffer from inflammation and leakage, which lessens their usefulness in studying delayed stem cell transplantation.

METHODS

Thoracic spinal cord at T9 level of adult Sprague-Dawley rats was exposed and a 50:50 sheet of poly(D,L-lactic-coglycolic acid) was inserted, exposed spinal cord was completely transected, and collagen was filled between the gap between the proximal and distal stumps of transected spinal cord. A microtube was placed and fixed between the polymer surfaces facing each other. Behavior testing, magnetic resonance imaging, and myelography were performed to characterize the new complete transection with a gap formation and polymer insertion (GAP) model and to compare the GAP model with the control models. Human mesenchymal stem cells (hMSCs) were transplanted into 3 models and immunohistochemistry and western blot were performed.

RESULTS

The inserted poly(D,L-lactic-coglycolic acid) sheet was completely disappeared 10 weeks after operation, but the inserted microtube remained firmly fixed in its original position. Myelography of the GAP model showed no leakage of contrast medium around the injured spinal cord, whereas magnetic resonance imaging of the severe contusion and simple transection models showed some leakage of contrast medium. Immunohistochemistry and western blot after hMSCs transplantation indicated that transplanted hMSCs survived and migrated well in the GAP model, and the deposition of inflammatory cells in GAP model was less than a simple transection model or severe contusion model.

CONCLUSION

The developed GAP model is more relevant for delayed transplantation of stem cells for the study of regeneration of spinal cord injury of rats.

Present state and future perspectives of using pluripotent stem cells in toxicology research

The use of novel drugs and chemicals requires reliable data on their potential toxic effects on humans. Current test systems are mainly based on animals or in vitro–cultured animal-derived cells and do not or not sufficiently mirror the situation in humans. Therefore, in vitro models based on human pluripotent stem cells (hPSCs) have become an attractive alternative. The article summarizes the characteristics of pluripotent stem cells, including embryonic carcinoma and embryonic germ cells, and discusses the potential of pluripotent stem cells for safety pharmacology and toxicology. Special attention is directed to the potential application of embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) for the assessment of developmental toxicology as well as cardio- and hepatotoxicology. With respect to embryotoxicology, recent achievements of the embryonic stem cell test (EST) are described and current limitations as well as prospects of embryotoxicity studies using pluripotent stem cells are discussed. Furthermore, recent efforts to establish hPSC-based cell models for testing cardio- and hepatotoxicity are presented. In this context, methods for differentiation and selection of cardiac and hepatic cells from hPSCs are summarized, requirements and implications with respect to the use of these cells in safety pharmacology and toxicology are presented, and future challenges and perspectives of using hPSCs are discussed.

Neurotrophic factors improve muscle reinnervation from embryonic neurons

Motoneurons die in diseases like amyotrophic lateral sclerosis and after spinal cord trauma, inducing muscle denervation. We tested whether transplantation of embryonic cells with neurotrophic factors into peripheral nerve of adult rats improves muscle reinnervation and motor unit function more than cells alone. One week after sciatic nerve section, embryonic ventral spinal cord cells were transplanted into the tibial nerve with or without glial cell line-derived neurotrophic factor, hepatocyte growth factor, and insulin-like growth factor-1. These cells represented the only neuron source for muscle reinnervation. Ten weeks after transplantation, all medial gastrocnemius muscles contracted in response to electrical stimulation of cell transplants with factors. Only 80% of muscles responded with cells alone. Factors and cells resulted in survival of more motoneurons and reinnervation of more muscle fibers for a given axon (motor unit) number. Greater reinnervation from embryonic cells may enhance muscle excitation by patterned electrical stimulation.

NIH-3T3 fibroblast transplants enhance host regeneration and improve spatial learning in ventral subicular lesioned rats

Transplants, besides providing neural replacement, also stimulate host regeneration, which could serve as a powerful means to establish functional recovery in CNS insults. Earlier, we have reported the H3-GFP transplant mediated recovery of cognitive functions in the ventral subicular lesioned rats. In the present study, we demonstrate the efficacy of a non-neural fibroblast transplants in mediating host regeneration and functional recovery in ventral subicular lesioned rats. Adult male Wistar rats were lesioned with ibotenic acid in the ventral subiculum (VSL) and were transplanted with NIH-3T3 fibroblast cells into CA1 region of the hippocampus. Ventral subicular lesioning impaired the spatial task performances in rats and produced considerable degree of dendritic atrophy of the hippocampal pyramidal neurons. Two months following transplantation, the transplants were seen in the dentate gyrus and expressed BDNF and bFGF. Further, the VSL rats with fibroblast transplants showed enhanced expression of BDNF in the hippocampus and enhanced dendritic branching and increased spine density in the CA1 hippocampal pyramidal neurons. Transplantation of fibroblast cells also helped to establish functional recovery and the rats with transplants showed enhanced spatial learning performances. We attribute the recovery of cognitive functions to the graft mediated host regeneration, although the mechanisms of functional recovery remain to be elucidated.

Embryonic stem cells inhibit expression of erythropoietin in the injured spinal cord

Recent observations have demonstrated neuroprotective role of erythropoietin (Epo) and Epo receptor in the central nervous system. Here we examined Epo function in the murine spinal cord after transplantation of pluripotent mouse embryonic stem (ES) cells pre-differentiated towards neuronal type following spinal cord injury. Expression of Epo was measured at both mRNA and protein levels in the ES cells as well as in the spinal cords after 1 and 7 days. Our data demonstrated that expression of Epo mRNA, as well as its protein content, in ES cells was significantly decreased after differentiation procedure. In the spinal cords, analysis showed that Epo mRNA level was significantly decreased after 1 day of ES cell injections in comparison to media-injected control. Epo protein level detected by Western blot was diminished as well. Examination of Epo production in the injured spinal cords after media or ES cells injections by indirect immunofluorescence showed increased Epo-immunopositive staining after media injections 1 day after injection. In contrast, ES cell transplantation did not induce Epo expression. Seven days after ES cell injections, Epo-immunopositive cells' distribution in the ipsilateral side was not changed, while the intensity of immunostaining on the contralateral side was increased, approaching levels in control media-injected tissues. Our data let us to presume that previously described immediate positive effects of ES cells injected into the injured zone of spinal cord are not based on Epo, but on other factors or hormones, which should be elucidated further.

Proliferation and pluripotency of human embryonic stem cells maintained on type I collagen

Human embryonic stem cells (hESC) require a balance of growth factors and signaling molecules to proliferate and retain pluripotency. Conditioned medium (CM) from a human embryonic germ-cell-derived cell culture, SDEC, was observed to support the growth of hESC on type I collagen (COL I) and on Matrigel (MAT) biomatricies. After 1 month, the population doubling of hESC grown in SDEC CM on COL I was equivalent to that of hESC grown in mouse embryonic fibroblast (MEF) CM on MAT. hESC grown in SDEC CM on COL I expressed OCT4, NANOG, SSEA-4, alkaline phosphatase (AP), and TRA-1-60; retained a normal karyotype; and were capable of forming teratomas. DNA microarray analysis was used to compare the transcriptional profiles of SDEC and the less supportive WI38 and Detroit 551 human cell lines. The mRNA level of secreted frizzled-related protein (sFRP-1), a known antagonist of the WNT/β-catenin signaling pathway, was significantly reduced in SDEC as compared with the other 2 cell lines, whereas the mRNA levels of prostaglandin-endoperoxide synthase 2 (PTGS2 or COX-2) and prostaglandin I₂ synthase (PGIS), two prostaglandin biosynthesis genes, were significantly increased in SDEC. The level of sFRP-1 protein was significantly reduced, and levels of 2 prostaglandins that are downstream products of PTGS2 and PGIS, prostaglandin E₂ and 6-keto-prostaglandin F(1α), were significantly elevated in SDEC CM compared with WI38, Detroit 551, and MEF CM. Further, addition of purified sFRP-1 to SDEC CM reduced the proliferation of hESC grown on COL I as well as MAT in a dose-dependent manner.