Cell replacement therapy for central nervous system diseases

Transplantation of Chemical Compound-Induced Cells from Human Fibroblasts Improves Locomotor Recovery in a Spinal Cord Injury Rat Model

The development of regenerative medicine using cell therapy is eagerly awaited for diseases such as spinal cord injury (SCI), for which there has been no radical cure. We previously reported the direct conversion of human fibroblasts into neuronal-like cells using only chemical compounds; however, it is unclear whether chemical compound-induced neuronal-like (CiN) cells are clinically functional. In this study, we partially modified the method of inducing CiN cells (termed immature CiN cells) and examined their therapeutic efficacy, in a rat model of SCI, to investigate whether immature CiN cells are promising for clinical applications. Motor function recovery, after SCI, was assessed using the Basso, Beattie, and Bresnahan (BBB) test, as well as the CatWalk analysis. We found that locomotor recovery, after SCI in the immature CiN cell-transplanted group, was partially improved compared to that in the control group. Consistent with these results, magnetic resonance imaging (MRI) and histopathological analyses revealed that nerve recovery or preservation improved in the immature CiN cell-transplanted group. Furthermore, transcriptome analysis revealed that immature CiN cells highly express hepatocyte growth factor (HGF), which has recently been shown to be a promising therapeutic agent against SCI. Our findings suggest that immature CiN cells may provide an alternative strategy for the regenerative therapy of SCI.

Microfluidic and Microscale Assays to Examine Regenerative Strategies in the Neuro Retina

Bioengineering systems have transformed scientific knowledge of cellular behaviors in the nervous system (NS) and pioneered innovative, regenerative therapies to treat adult neural disorders. Microscale systems with characteristic lengths of single to hundreds of microns have examined the development and specialized behaviors of numerous neuromuscular and neurosensory components of the NS. The visual system is comprised of the eye sensory organ and its connecting pathways to the visual cortex. Significant vision loss arises from dysfunction in the retina, the photosensitive tissue at the eye posterior that achieves phototransduction of light to form images in the brain. Retinal regenerative medicine has embraced microfluidic technologies to manipulate stem-like cells for transplantation therapies, where de/differentiated cells are introduced within adult tissue to replace dysfunctional or damaged neurons. Microfluidic systems coupled with stem cell biology and biomaterials have produced exciting advances to restore vision. The current article reviews contemporary microfluidic technologies and microfluidics-enhanced bioassays, developed to interrogate cellular responses to adult retinal cues. The focus is on applications of microfluidics and microscale assays within mammalian sensory retina, or neuro retina, comprised of five types of retinal neurons (photoreceptors, horizontal, bipolar, amacrine, retinal ganglion) and one neuroglia (Müller), but excludes the non-sensory, retinal pigmented epithelium.

Paths to Successful Translation of New Therapies for Severe Traumatic Brain Injury in the Golden Age of Traumatic Brain Injury Research: A Pittsburgh Vision

New neuroprotective therapies for severe traumatic brain injury (TBI) have not translated from pre-clinical to clinical success. Numerous explanations have been suggested in both the pre-clinical and clinical arenas. Coverage of TBI in the lay press has reinvigorated interest, creating a golden age of TBI research with innovative strategies to circumvent roadblocks. We discuss the need for more robust therapies. We present concepts for traditional and novel approaches to defining therapeutic targets. We review lessons learned from the ongoing work of the pre-clinical drug and biomarker screening consortium Operation Brain Trauma Therapy and suggest ways to further enhance pre-clinical consortia. Biomarkers have emerged that empower choice and assessment of target engagement by candidate therapies. Drug combinations may be needed, and it may require moving beyond conventional drug therapies. Precision medicine may also link the right therapy to the right patient, including new approaches to TBI classification beyond the Glasgow Coma Scale or anatomical phenotyping-incorporating new genetic and physiologic approaches. Therapeutic breakthroughs may also come from alternative approaches in clinical investigation (comparative effectiveness, adaptive trial design, use of the electronic medical record, and big data). The full continuum of care must also be represented in translational studies, given the important clinical role of pre-hospital events, extracerebral insults in the intensive care unit, and rehabilitation. TBI research from concussion to coma can cross-pollinate and further advancement of new therapies. Misconceptions can stifle/misdirect TBI research and deserve special attention. Finally, we synthesize an approach to deliver therapeutic breakthroughs in this golden age of TBI research.

Effects of GDNF-Transfected Marrow Stromal Cells on Rats with Intracerebral Hemorrhage

OBJECTIVE

The present study aimed to investigate the effects of Mesenchymal stem cells/glial cell line derived neurotrophic factor (MSCs/GDNF) transplantation on nerve reconstruction in rats with intracerebral hemorrhage.

METHODS

GDNF transduction to MSCs was using adenovirus vector pAdEasy-1-pAdTrack-CMV prepared. Intracerebral hemorrhage (ICH) was induced by injection of collagenase and heparin into the caudate putamen. At the third day after a collagenase-induced ICH, adult male SD rats were randomly divided into saline group, MSCs group and MSCs/GDNF group. Immunofluorescence and RT-PCR were performed to detect the differentiation of MSCs or MSCs with an adenovirus vector encoding GDNF gene in vivo and in vitro.

RESULT

After 6 hours of induction, both MSCs and MSCs/GDNF expressed neuro or glial specific markers and synaptic-associated proteins (SYN, GAP-43, PSD-95); additionally, they secreted bioactive compounds (BDNF, NGF-β). MSCs/GDNF transplantation, compared to MSCs and saline solution injection, significantly improved neurological functions after ICH. The grafted MSCs or MSCs/GDNF survived in the striatum after 2 weeks of transplantation and expressed the neural cell-specific biomarkers NSE, MAP2, and GFAP.

CONCLUSION

These findings demonstrate that MSCs/GDNF transplantation contributes to improved neurological function in experimental ICH rats. The mechanisms are possibly due to neuronal replacement and enhanced neurotrophic factor secretion.

MRI Tracking of iPS Cells-Induced Neural Stem Cells in Traumatic Brain Injury Rats

Induced pluripotent stem cells (iPS cells) are promising cell source for stem cell replacement strategy applied to brain injury caused by traumatic brain injury (TBI) or stroke. Neural stem cell (NSCs) derived from iPS cells could aid the reconstruction of brain tissue and the restoration of brain function. However, tracing the fate of iPS cells in the host brain is still a challenge. In our study, iPS cells were derived from skin fibroblasts using the four classic factors Oct4, Sox2, Myc, and Klf4. These iPS cells were then induced to differentiate into NSCs, which were incubated with superparamagnetic iron oxides (SPIOs) in vitro. Next, 30 TBI rat models were prepared and divided into three groups (n = 10). One week after brain injury, group A&B rats received implantation of NSCs (labeled with SPIOs), while group C rats received implantation of non-labeled NSCs. After cell implantation, all rats underwent T2*-weighted magnetic resonance imaging (MRI) scan at day 1, and 1 week to 4 weeks, to track the distribution of NSCs in rats' brains. One month after cell implantation, manganese-enhanced MRI (ME-MRI) scan was performed for all rats. In group B, diltiazem was infused during the ME-MRI scan period. We found that (1) iPS cells were successfully derived from skin fibroblasts using the four classic factors Oct4, Sox2, Myc, and Klf4, expressing typical antigens including SSEA4, Oct4, Sox2, and Nanog; (2) iPS cells were induced to differentiate into NSCs, which could express Nestin and differentiate into neural cells and glial cells; (3) NSCs were incubated with SPIOs overnight, and Prussian blue staining showed intracellular particles; (4) after cell implantation, T2*-weighted MRI scan showed these implanted NSCs could migrate to the injury area in chronological order; (5) the subsequent ME-MRI scan detected NSCs function, which could be blocked by diltiazem. In conclusion, using an in vivo MRI tracking technique to trace the fate of iPS cells-induced NSCs in host brain is feasible.

Functional Recovery Following the Transplantation of Olfactory Ensheathing Cells in Rat Spinal Cord Injury Model

Study Design

Olfactory ensheathing cells (OECs) from rat olfactory mucosa were cultured, characterized, and transplanted into a rat model of spinal cord injury (SCI).

Purpose

To evaluate different doses of OECs in a rat model of SCI.

Overview of Literature

SCI causes permanent functional deficit because the central nervous system lacks the ability to perform spontaneous repair. Cell therapy strategies are being explored globally. The clinical use of human embryonic stem cell is hampered by ethical controversies. Alternatively, OECs are a promising cell source for neurotransplantation. This study aimed to evaluate the efficacy of different doses of allogenic OEC transplantation in a rat model of SCI.

Methods

OECs were cultured from the olfactory mucosa of Albino Wistar rats; these cells were characterized using immunohistochemistry and flow cytometry. Rats were divided into five groups (n=6 rats each). In each group, different dosage (2×10⁵, 5×10⁵, 10×10⁵, and >10×10⁵) of cultured cells were transplanted into experimentally injured spinal cords of rat models. However, in the SCI group, only DMEM (Dulbecco’s modified Eagle's medium) was injected. Rats were followed up upto 8 weeks post-transplantation. The outcome of transplantation was assessed using the Basso, Beattie, Bresnahan (BBB) scale; motor-evoked potential studies; and histological examination.

Results

Cultured cells expressed 41% of p75NTR, a marker for OEC, and 35% of anti-fibronectin, a marker for olfactory nerve fibroblast. These cells also expressed S100β and glial fibrillary acid protein of approximately 75% and 83%, respectively. All the transplanted groups showed promising BBB scores for hind-limb motor recovery compared with the SCI group (p<0.05). A motor-evoked potential study showed increased amplitude in all the treated groups compared with the SCI. Green fluorescent protein-labeled cells survived in the injured cord, suggesting their role in the transplantation-mediated repair. Transplantation of 5×10⁵ cells showed the best motor outcomes among all the doses.

Conclusions

OECs demonstrated a therapeutic effect in rat models with the potential for future clinical applications.

Adult Neural Stem Cells: Basic Research and Production Strategies for Neurorestorative Therapy

Over many decades, constructing genetically and phenotypically stable lines of neural stem cells (NSC) for clinical purposes with the aim of restoring irreversibly lost functions of nervous tissue has been one of the major goals for multiple research groups. The unique ability of stem cells to maintain their own pluripotent state even in the adult body has made them into the choice object of study. With the development of the technology for induced pluripotent stem cells (iPSCs) and direct transdifferentiation of somatic cells into the desired cell type, the initial research approaches based on the use of allogeneic NSCs from embryonic or fetal nervous tissue are gradually becoming a thing of the past. This review deals with basic molecular mechanisms for maintaining the pluripotent state of embryonic/induced stem and reprogrammed somatic cells, as well as with currently existing reprogramming strategies. The focus is on performing direct reprogramming while bypassing the stage of iPSCs which is known for genetic instability and an increased risk of tumorigenesis. A detailed description of various protocols for obtaining reprogrammed neural cells used in the therapy of the nervous system pathology is also provided.

Promotion and guidance of neural network formation on SU-8 photoresist microchannels adjusted with multilayer films

Induction of neural stem/progenitor cells (NSPCs) and establishment of neural network are important issues on neural engineering. In this work, a platform was designed to control and evaluate the differentiation of NSPCs, neurite direction, and to promote the neurite outgrowth. Polyelectrolyte multilayer (PEM) films provide surface properties by and have been used to regulate NSPCs differentiation in our previous study. Herein, a culture platform composed of SU-8 microchannel and PEM films was designed to achieve the goal of promoting NSPCs differentiation and to evaluate the effect of PEM films on the guidance of neural network formation. In this culture platform, NSPCs were induced into functional neurons, and neural network formation was accomplished on ITO glass-PEM films successfully.

Neural Progenitor Cells Promote Axonal Growth and Alter Axonal mRNA Localization in Adult Neurons

The inhibitory environment of the spinal cord and the intrinsic properties of neurons prevent regeneration of axons following CNS injury. However, both ascending and descending axons of the injured spinal cord have been shown to regenerate into grafts of embryonic neural progenitor cells (NPCs). Previous studies have shown that grafts composed of glial-restricted progenitors (GRPs) and neural-restricted progenitors (NRPs) can provide a permissive microenvironment for axon growth. We have used cocultures of adult rat dorsal root ganglion (DRG) neurons together with NPCs, which have shown significant enhancement of axon growth by embryonic rat GRP and GRPs/NRPs, both in coculture conditions and when DRGs are exposed to conditioned medium from the NPC cultures. This growth-promoting effect of NPC-conditioned medium was also seen in injury-conditioned neurons. DRGs cocultured with GRPs/NRPs showed altered expression of regeneration-associated genes at transcriptional and post-transcriptional levels. We found that levels of GAP-43 mRNA increased in DRG cell bodies and axons. However, hepcidin antimicrobial peptide (HAMP) mRNA decreased in the cell bodies of DRGs cocultured with GRPs/NRPs, which is distinct from the increase in cell body HAMP mRNA levels seen in DRGs after injury conditioning. Endogenous GAP-43 and β-actin mRNAs as well as reporter RNAs carrying axonally localizing 3'UTRs of these transcripts showed significantly increased levels in distal axons in the DRGs cocultured with GRPs/NRPs. These results indicate that axon growth promoted by NPCs is associated not only with enhanced transcription of growth-associated genes but also can increase localization of some mRNAs into growing axons.

Stem cells for spinal cord injury: Strategies to inform differentiation and transplantation

The complex pathology of spinal cord injury (SCI), involving a cascade of secondary events and the formation of inhibitory barriers, hampers regeneration across the lesion site and often results in irreversible loss of motor function. The limited regenerative capacity of endogenous cells after SCI has led to a focus on the development of cell therapies that can confer both neuroprotective and neuroregenerative benefits. Stem cells have emerged as a candidate cell source because of their ability to self-renew and differentiate into a multitude of specialized cell types. While ethical and safety concerns impeded the use of stem cells in the past, advances in isolation and differentiation methods have largely mitigated these issues. A confluence of work in stem cell biology, genetics, and developmental neurobiology has informed the directed differentiation of specific spinal cell types. After transplantation, these stem cell-derived populations can replace lost cells, provide trophic support, remyelinate surviving axons, and form relay circuits that contribute to functional recovery. Further refinement of stem cell differentiation and transplantation methods, including combinatorial strategies that involve biomaterial scaffolds and drug delivery, is critical as stem cell-based treatments enter clinical trials. Biotechnol. Bioeng. 2017;114: 245-259. © 2016 Wiley Periodicals, Inc.

Globose basal cells for spinal cord regeneration

Spinal cord injury (SCI) is a devastating condition with loss of motor and sensory functions below the injury level. Cell based therapies are experimented in pre-clinical studies around the world. Neural stem cells are located intra-cranially in subventricular zone and hippocampus which are highly invasive sources. The olfactory epithelium is a neurogenic tissue where neurogenesis takes place throughout the adult life by a population of stem/progenitor cells. Easily accessible olfactory neuroepithelial stem/progenitor cells are an attractive cell source for transplantation in SCI. Globose basal cells (GBCs) were isolated from rat olfactory epithelium, characterized by flow cytometry and immunohistochemically. These cells were further studied for neurosphere formation and neuronal induction. T10 laminectomy was done to create drop-weight SCI in rats. On the 9^th day following SCI, 5 × 10⁵ cells were transplanted into injured rat spinal cord. The outcome of transplantation was assessed by the Basso, Beattie and Bresnahan (BBB) locomotor rating scale, motor evoked potential and histological observation. GBCs expressed neural stem cell markers nestin, SOX2, NCAM and also mesenchymal stem cell markers (CD29, CD54, CD90, CD73, CD105). These cells formed neurosphere, a culture characteristics of NSCs and on induction, differentiated cells expressed neuronal markers βIII tubulin, microtubule-associated protein 2, neuronal nuclei, and neurofilament. GBCs transplanted rats exhibited hindlimb motor recovery as confirmed by BBB score and gastrocnemius muscle electromyography amplitude was increased compared to controls. Green fluorescent protein labelled GBCs survived around the injury epicenter and differentiated into βIII tubulin-immunoreactive neuron-like cells. GBCs could be an alternative to NSCs from an accessible source for autologous neurotransplantation after SCI without ethical issues.

Neural differentiation potential of sympathoadrenal progenitors derived from fresh and cryopreserved neonatal porcine adrenal glands

Stem/progenitor cells are thought to have the potential in the treatment of severe neurodegenerative diseases. Recently, sympathoadrenal progenitors expressing specific markers of neural crest derivatives and capable to differentiate into neurons were discovered in adult bovine and human adrenal glands, but there was no reported data on cryopreservation of sympathoadrenal progenitors. The aim of the present study was to examine the neural differentiation potential of sympathoadrenal progenitors derived from fresh and cryopreserved neonatal porcine adrenal glands. Considering impact of various initial state of frozen biomaterial on cell recovery, we carried out a comparative estimation of cryopreservation outcome both for adrenal tissue fragments and isolated primary cells. The estimation consisted of determining cell yield, viability, ability to adhere, proliferate and differentiate in vitro. Cells isolated from the fresh adrenal glands were cultured until confluence. A formation of sympathoadrenal progenitors-embedded spherical cell colonies, whose cells are differentiated then into βIII-tubulin-positive cells with neuron-like morphology, was observed on the monolayer. The colonies were well preserved after cryopreservation of cell culture with a cooling rate of 1 °C/min in the cryoprotectant media containing 5-15% of dimethylsulfoxide. Adrenal tissue fragments were cryopreserved in the presence of 10% dimethylsulfoxide at the cooling rates of 0.3; 1: 5; 40 and > 100 °C/min. Sympathoadrenal progenitors were recovered after cryopreservation with 0.3 °C/min cooling rate but not higher.

The Role of Stem Cells in the Treatment of Cerebral Palsy: a Review

Cerebral palsy (CP) is a neuromuscular disease due to injury in the infant's brain. The CP disorder causes many neurologic dysfunctions in the patient. Various treatment methods have been used for the management of CP disorder. However, there has been no absolute cure for this condition. Furthermore, some of the procedures which are currently used for relief of symptoms in CP cause discomfort or side effects in the patient. Recently, stem cell therapy has attracted a huge interest as a new therapeutic method for treatment of CP. Several investigations in animal and human with CP have demonstrated positive potential of stem cell transplantation for the treatment of CP disorder. The ultimate goal of this therapeutic method is to harness the regenerative capacity of the stem cells causing a formation of new tissues to replace the damaged tissue. During the recent years, there have been many investigations on stem cell therapy. However, there are still many unclear issues regarding this method and high effort is needed to create a technology as a perfect treatment. This review will discuss the scientific background of stem cell therapy for cerebral palsy including evidences from current clinical trials.