Intracerebral Transplantation Research Articles

Efficacy of the new therapeutic approach in curing malignant neoplasms on the model of human glioblastoma.

Objective:Glioma is a highly invasive tumor, frequently disposed in essential areas of the brain, which makes its surgical excision extremely difficult; meanwhile adjuvant therapy remains quite ineffective.Methods:In the current report, a new therapeutic approach in curing malignant neoplasms has been performed on the U87 human glioblastoma model. This approach, termed “Karanahan”, is aimed at the eradication of cancer stem cells (CSCs), which were recently shown to be capable of internalizing fragments of extracellular double-stranded DNA. After being internalized, these fragments interfere in the process of repairing interstrand cross-links caused by exposure to appropriate cytostatics, and such an interference results either in elimination of CSCs or in the loss of their tumorigenic potency. Implementation of the approach requires a scheduled administration of cytostatic and complex composite double-stranded DNA preparation.Results:U87 cells treated in vitro in accordance with the Karanahan approach completely lost their tumorigenicity and produced no grafts upon intracerebral transplantation into immunodeficient mice. In SCID mice with developed subcutaneous grafts, the treatment resulted in reliable slowing down of tumor growth rate (P < 0.05). In the experiment with intracerebral transplantation of U87 cells followed by surgical excision of the developed graft and subsequent therapeutic treatment, the Karanahan approach was shown to reliably slow down the tumor growth rate and increase the median survival of the mice twofold relative to the control.Conclusions:The effectiveness of the Karanahan approach has been demonstrated both in vitro and in vivo in treating developed subcutaneous grafts as well as orthotopic grafts after surgical excision of the tumor.

Intracerebral Transplantation of Neural Stem Cells Restores Manganese-Induced Cognitive Deficits in Mice.

Manganese (Mn) is a potent neurotoxin known to cause long-lasting structural damage and progressive cognitive deficits in the brain. However, new therapeutic approaches are urgently needed since current treatments only target symptoms of Mn exposure. Recent studies have suggested a potential role for multipotent neural stem cells (NSCs) in the etiology of Mn-induced cognitive deficits. In this study, we evaluated the effect of direct intracerebral transplantation of NSCs on cognitive function of mice chronically exposed to MnCl2, and further explored the distribution of transplanted NSCs in brain tissues. NSCs were isolated and bilaterally injected into the hippocampal regions or lateral ventricles of Mn-exposed mice. The results showed that many transplanted cells migrated far away from the injection sites and survived in vivo in the Mn-exposed mouse brain, implying enhanced neurogenesis in the host brain. We found that NSCs transplanted into either the hippocampal regions or the lateral ventricles significantly improved spatial learning and memory function of the Mn-exposed mice in the Morris water maze. Immunofluorescence analyses indicated that some surviving NSCs differentiated into neurons or glial cells, which may have become functionally integrated into the impaired local circuits, providing a possible cellular basis for the improvement of cognitive function in NSC-transplanted mice. Taken together, our findings confirm the Mn-induced impairment of neurogenesis in the brain and underscore the potential of treating Mn exposure by NSC transplantation, providing a practical therapeutic strategy against this type of neurotoxicity.

Cell therapy for ischemic stroke

Stroke is the second, and in some countries the third cause of mortality in the population and one of the causes of disability in the adult population. According to statistics, in 2018, 15 million cases of stroke and 6 million deaths were diagnosed,The only currently approved treatments for acute stroke are intravenous tissue plasminogen activator (rtPA) and intra-arterial thrombectomy, which are used in less than 10% and 1% of patients, respectively.The literature review is devoted to the pathophysiology and molecular mechanisms of damage in cerebral ischemia. The modern concept of two strategies of cell therapy is discussed: neuroprotection and remodeling; the role of stem cells in reducing local and systemic inflammation, neurogenesis and angiogenesis, increasing neuronal plasticity, and protecting the blood-brain barrier, the role of paracrine factors and extracellular vesicles is shown.Methods of stem cell delivery are described: direct intracerebral transplantation, intraventricular and intrathecal, intravenous and intraarterial; the number of cells, their type and optimal delivery time depending on the acute, subacute and chronic periods of stroke. We also described recently designed the radially branched deployment (RBD) device and Cleveland multiport catheter for convection-enhanced delivery in which a cell-delivery catheter can be deployed at various angles and depths from a single longitudinal cannula. Finally, data on the completed 15 clinical trials from 2015 to the present, in which 513 patients took part, are presented. A detailed analysis of the efficacy and safety of cell therapy has been carried out.

Cell therapy in Huntington's disease: Taking stock of past studies to move the field forward.

Huntington's disease (HD) is a rare inherited neurodegenerative disease that manifests mostly in adulthood with progressive cognitive, behavioral, and motor dysfunction. Neuronal loss occurs predominantly in the striatum but also extends to other brain regions, notably the cortex. Most patients die around 20 years after motor onset, although there is variability in the rate of progression and some phenotypic heterogeneity. The most advanced experimental therapies currently are huntingtin-lowering strategies, some of which are in stage 3 clinical trials. However, even if these approaches are successful, it is unlikely that they will be applicable to all patients or will completely halt continued loss of neural cells in all cases. On the other hand, cellular therapies have the potential to restore atrophied tissues and may therefore provide an important complementary therapeutic avenue. Pilot studies of fetal cell grafts in the 2000s reported the most dramatic clinical improvements yet achieved for this disease, but subsequent studies have so far failed to identify methodology to reliably reproduce these results. Moving forward, a major challenge will be to generate suitable donor cells from (nonfetal) cell sources, but in parallel there are a host of procedural and trial design issues that will be important for improving reliability of transplants and so urgently need attention. Here, we consider findings that have emerged from clinical transplant studies in HD to date, in particular new findings emerging from the recent multicenter intracerebral transplant HD study, and consider how these data may be used to inform future cell therapy trials.

Intracerebral Transplants of GMP-Grade Human Umbilical Cord-Derived Mesenchymal Stromal Cells Effectively Treat Subacute-Phase Ischemic Stroke in a Rodent Model.

In subacute and chronic phases of the stroke, there are no therapeutics available at present to promote functional recovery. Human umbilical cord-derived mesenchymal stromal cells (hUC-MSCs) are one of the candidate cell types for treating subacute-phase stroke. The benefits of cell-based therapy largely depend on the migratory capacity of products administered, as well as their potential for engraftment in targeted tissues and paracrine activities. Timing and delivery modes may also influence the outcomes of stem-cell therapy. Still, the functional recuperative effects of differing hUC-MSC delivery modes, about cell replacement and cell-to-cell paracrine activity levels, have yet to be clarified in subacute phases of stroke.This study was conducted to compare the therapeutic effects of various delivery routes when administering Good Manufacturing Practice (GMP)-grade hUC-MSCs in a rodent model of subacute-phase stroke. Cell aliquots (1 × 106) were given to rats as intravenous (IV) injections or intracerebral (IC) transplants 1 week after middle cerebral artery occlusion (MCAo). Transplanted rats were examined up to 7 weeks later using various behavioral tests and immunohistochemical analyses. Most IC-transplanted cells survived for short periods (i.e., <4 weeks after receipt) and gradually disappeared, whereas IV-injected cells were undetectable in the brain at the same time points (i.e., 3 days, 4 weeks, or 7 weeks after injection). Although short-lived, IC-transplanted cells effectively improved behavioral deficits, serving to reduce infarct volumes and glial scar formation, increase subventricular counts of proliferating neuroblasts, and promote cerebrovascular ingrowth in ischemic penumbra regions. IV injection, however, failed to improve behavioral function or histologic parameters during the same 7-week time frame. These findings overall suggest that IC transplantation is preferable to IV injection for delivery of hUC-MSCs during subacute phases of stroke.

Intracerebral transplantation of HLA-homozygous human iPSC-derived neural precursors ameliorates the behavioural and pathological deficits in a rodent model of ischaemic stroke.

ObjectivesHuman‐induced pluripotent stem cells (hiPSCs) are a promising cell source for treating ischaemic stroke. Although autologous hiPSCs provide the advantage of avoiding immune rejection, their practical limitations, such as substantial amount of time and costs to generate individual iPSC lines, have hampered their widespread application in clinical settings. In this study, we investigated the therapeutic potential of neural precursor cells derived from human HLA‐homozygous induced pluripotent stem cells (hiPSC‐NPCs) following intracerebral transplantation into a rodent model of middle cerebral artery occlusion (MCAo).Materials and MethodsWe differentiated a GMP‐grade HLA‐homozygous hiPSC line (CMC‐hiPSC‐004) into neural precursor cells for transplantation into rats at the subacute stage of ischaemic stroke (ie at 7 days after the induction of MCAo). To investigate functional recovery, the transplanted animals were subjected to five behavioural tests, namely the rotarod, stepping, mNSS, staircase and apomorphine‐induced rotation tests, for up to 12 weeks, followed by histological analyses.ResultsWe observed that the hiPSC‐NPC transplantation produced significant behavioural improvements. At 12 weeks post‐transplantation, a high proportion of transplanted cells survived and had differentiated into MAP2+ mature neurons, GABAergic neurons and DARPP32+ medium spiny neurons. The transplanted cells formed neuronal connections with striatal neurons in the host brain. In addition, hiPSC‐NPC transplantation gave rise to enhanced endogenous repair processes, including decreases of post‐stroke neuroinflammation and glial scar formation and an increase of proliferating endogenous neural stem cells in the subventricular zone as well as the perilesional capillary networks.ConclusionsThese results strongly suggest that HLA‐homozygous hiPSC‐NPCs may be useful for treating ischaemic stroke patients.

Adipose-Derived Stem Cells Reduce Lipopolysaccharide-Induced Myelin Degradation and Neuroinflammatory Responses of Glial Cells in Mice.

Brain inflammation is a key event triggering the pathological process associated with many neurodegenerative diseases. Current personalized medicine and translational research in neurodegenerative diseases focus on adipose-derived stem cells (ASCs), because they are patient-specific, thereby reducing the risk of immune rejection. ASCs have been shown to exert a therapeutic effect following transplantation in animal models of neuroinflammation. However, the mechanisms by which transplanted ASCs promote cell survival and/or functional recovery are not fully understood. We investigated the effects of ASCs in in vivo and in vitro lipopolysaccharide (LPS)-induced neuroinflammatory models. Brain damage was evaluated immunohistochemically using specific antibody markers of microglia, astroglia and oligodendrocytes. ASCs were used for intracerebral transplantation, as well as for non-contact co-culture with brain slices. In both in vivo and in vitro models, we found that LPS caused micro- and astroglial activation and oligodendrocyte degradation, whereas the presence of ASCs significantly reduced the damaging effects. It should be noted that the observed ASCs protection in a non-contact co-culture suggested that this effect was due to humoral factors via ASC-released biomodulatory molecules. However, further clinical studies are required to establish the therapeutic mechanisms of ASCs, and optimize their use as a part of a personalized medicine strategy.

Intracerebral Transplantation of BDNF-overexpressing Human Neural Stem Cells (HB1.F3.BDNF) Promotes Migration, Differentiation and Functional Recovery in a Rodent Model of Huntington's Disease.

Huntington’s disease (HD) is a dominantly inherited neurodegenerative disorder caused by abnormally expanded CAG repeats in the huntingtin gene. The huntingtin gene mutation leads to the progressive degeneration of striatal GABAergic medium spiny neurons (MSN) and reduces the level of brain-derived neurotrophic factor (BDNF) in HD patient’s brain. BDNF is an essential neurotrophic factor for the cortico-striatal synaptic activity and the survival of GABAergic neurons. In this study, we transplanted BDNF-overexpressing human neural stem cells (HB1.F3.BDNF) into the contra-lateral side of unilateral quinolinic acid (QA)-lesioned striatum of HD rat model. The results of in vivo transplantation were monitored using various behavioral tests, 4.7 T animal magnetic resonance imaging (MRI) and immunohistochemical staining. We observed that the QA-lesioned rats receiving HB1.F3.BDNF cells exhibited significant behavioral improvements in the stepping, rotarod and apomorphine-induced rotation tests. Interestingly, contralaterally transplanted cells were migrated to the QA-lesioned striatum and the size of lateral ventricle was reduced. Histological analyses further revealed that the transplanted cells, which had migrated to the QA lesion site, were differentiated into the cells of GABAergic, MSN-type neurons expressing DARPP-32, and neural networks were established between the transplanted cells and the host brain, as revealed by retrograde tracing. Finally, there was a significant reduction of inflammatory response in HB1.F3.BDNF-transplanted HD animal model, compared with vehicle-transplanted group. Taken together, these results suggest that HB1.F3.BDNF can be an effective therapeutic strategy to treat HD patients in the future.

Multimodal Therapeutic Effects of Neural Precursor Cells Derived from Human-Induced Pluripotent Stem Cells through Episomal Plasmid-Based Reprogramming in a Rodent Model of Ischemic Stroke.

Stem cell therapy is a promising option for treating functional deficits in the stroke-damaged brain. Induced pluripotent stem cells (iPSCs) are attractive sources for cell therapy as they can be efficiently differentiated into neural lineages. Episomal plasmids (EPs) containing reprogramming factors can induce nonviral, integration-free iPSCs. Thus, iPSCs generated by an EP-based reprogramming technique (ep-iPSCs) have an advantage over gene-integrating iPSCs for clinical applications. However, there are few studies regarding the in vivo efficacy of ep-iPSCs. In this study, we investigated the therapeutic potential of intracerebral transplantation of neural precursor cells differentiated from ep-iPSCs (ep-iPSC-NPCs) in a rodent stroke model. The ep-iPSC-NPCs were transplanted intracerebrally in a peri-infarct area in a rodent stroke model. Rats transplanted with fibroblasts and vehicle were used as controls. The ep-iPSC-NPC-transplanted animals exhibited functional improvements in behavioral and electrophysiological tests. A small proportion of ep-iPSC-NPCs were detected up to 12 weeks after transplantation and were differentiated into both neuronal and glial lineages. In addition, transplanted cells promoted endogenous brain repair, presumably via increased subventricular zone neurogenesis, and reduced poststroke inflammation and glial scar formation. Taken together, these results strongly suggest that intracerebral transplantation of ep-iPSC-NPCs is a useful therapeutic option to treat clinical stroke through multimodal therapeutic mechanisms.

Abstract 45: Intracerebral Transplantation of Autologous Bone Marrow Stem Cell (BMSC) Against Acute Ischemic Stroke, Preliminary Data of Phase 1 Clinical Trial (RAINBOW Project)

Background: Recent breakthrough in cell therapy is expected to reverse the neurological sequelae of stroke. Prior studies have demonstrated that bone marrow stromal cells (BMSC) have therapeutic potential against stroke. In this study, we investigated the use of autologous BMSC transplantation for acute ischemic stroke through direct transplantation route with several new aspects including cell labeling and tracking, socioecomonic analysis using QALY, and the use of human platelet lysate (PL) instead of fetal bovine serum. This study is called the Research on Advanced Intervention using Novel Bone marrOW stem cell (RAINBOW, UNIN ID: UMIN000026130). Methods/Design: RAINBOW is a phase 1, open-label, uncontrolled, dose-response study, with the primary aim to determine the safety of the autologous BMSC administered to the patients with acute ischemic stroke. Estimated enrollment is 7 patients suffering severe neurological deficits. Approximately 50 mL of the bone marrow is extracted from the iliac bone of each patient 15 days or later from the onset, and BMSCs are cultured with allogeneic PL and are labeled with superparamagnetic iron oxide for cell tracking using magnetic resonance imaging (MRI). BMSCs are stereotactically administered around the area of infarction in the subacute phase. Each patient will be administered a dose of 20 or 50 million cells. Neurological scoring, MRI for cell tracking, 18 F-fuorodeoxyglucose positron emission tomography, and 123 I-Iomazenil single photon emission computed tomography will be performed throughout 1 year after the administration. Results: 6 patients have successfully finished cell transplantation, and there was no severe adverse event in any of the patient during surgical and follow-up period. Favorable motor recoveries are seen in 5 of 6 patients, and cell engraftment and migration to ischemic site was also observed by magnetic resonance imaging. Discussion: This is a first-in-human trial to use labelled BMSC to the patients with acute ischemic stroke. Intracerebral transplantation of autologous BMSC is safe and well tolerated. Moreover, it is expected that the bio-imaging techniques can clarify the therapeutic mechanisms.

Effect of Transplantation of Neural Stem and Progenitor Cells on Memory in Animals with Alzheimer's Type Neurodegeneration.

The effects of systemic and intracerebral transplantation of human fetal neural stem and progenitor cells were studied on the model of olfactory bulbectomy in mice with developing signs of sporadic Alzheimer's disease. It was found that transplantation of these cells at certain stages of disease development contributed to improvement of spatial memory and preservation of hippocampal neurons in these animals.

Glial cells in intracerebral transplantation for Parkinson's disease.

In the last few decades, intracerebral transplantation has grown from a dubious neuroscientific topic to a plausible modality for treatment of neurological disorders. The possibility for cell replacement opens a new field of perspectives in the therapy of neurodegenerative disorders, ischemia, and neurotrauma, with the most lessons learned from intracerebral transplantation in Parkinson’s disease. Multiple animal studies and a few small-scale clinical trials have proven the concept of intracerebral grafting, but still have to provide a uniform and highly efficient approach to the procedure, suitable for clinical application. The success of intracerebral transplantation is highly dependent on the integration of the grafted cells with the host brain. In this process, glial cells are clearly more than passive bystanders. They provide transplanted cells with mechanical support, trophics, mediate synapse formation, and participate in graft vascularization. At the same time, glial cells mediate scarring, graft rejection, and neuroinflammation, which can be detrimental. We can use this information to try to understand the mechanisms behind the glial reaction to intracerebral transplantation. Recognizing and utilizing glial reactivity can move translational research forward and provide an insight not only to post-transplantation events but also to mechanisms of neuronal death and degeneration. Knowledge about glial reactivity to transplanted cells could also be a key for optimization of transplantation protocols, which ultimately should contribute to greater patient benefit.

Transplantation of Adipose-Derived Stem Cells Alleviates Striatal Degeneration in a Transgenic Mouse Model for Multiple System Atrophy

Patients with multiple system atrophy (MSA), a progressive neurodegenerative disorder of adult onset, were found less than 9 years of life expectancy after onset. The disorders include bradykinesia and rigidity commonly seen in Parkinsonism disease and additional signs such as autonomic dysfunction, ataxia, or dementia. In clinical treatments, MSA poorly responds to levodopa, the drug used to remedy Parkinsonism disease. The exact cause of MSA is still unknown, and exploring a therapeutic solution to MSA remains critical. A transgenic mouse model was established to study the feasibility of human adipose-derived stem cell (ADSC) therapy in vivo. The human ADSCs were transplanted into the striatum of transgenic mice via intracerebral injection. As compared with sham control, we reported significantly enhanced rotarod performance of transgenic mice treated with ADSC at an effective dose, 2 × 105 ADSCs/mouse. Our ex vivo feasibility study supported that intracerebral transplantation of ADSC might alleviate striatal degeneration in MSA transgenic mouse model by improving the nigrostriatal pathway for dopamine, activating autophagy for α-synuclein clearance, decreasing inflammatory signal, and further cell apoptosis, improving myelination and cell survival at caudate-putamen.

Olfactory ensheathing cells improve the survival of porcine neural xenografts in a Parkinsonian rat model.

Parkinson's disease (PD) features the motor control deficits resulting from irreversible, progressive degeneration of dopaminergic (DA) neurons of the nigrostriatal pathway. Although intracerebral transplantation of human fetal ventral mesencephalon (hfVM) has been proven effective at reviving DA function in the PD patients, this treatment isclinically limited by availability of hfVMand the relatedethical issues. Homologous tissuesto hfVM, such as porcine fetal ventral mesencephalon (pfVM) thus present a strong clinical potential if immune response following xenotransplantation could be tamed. Olfactory ensheathing cells (OECs) are glial cells showing immunomodulatory properties. It is unclear but intriuging whether these properties can be applied to reducing immune response following neural xenotransplantation of PD. To determine whether OECs may benefit neural xenografts for PD, different compositions of grafting cellswere transplanted into striatum of the PD model rats. We used apomorphine-induced rotational behavior to evaluate effectiveness of the neural grafts on reviving DA function. Immunohistochemistry was applied to investigate the effect of OECs on the survival of neuroxenografts and underlyingmechanisms ofthis effect. Four weeks following the xenotransplantation, we found that the PD rats receiving pfVM+OECs co-graft exhibited a better improvement in apomorphine-induced rotational behavior compared with those receiving only pfVM cells. This result can be explained by higher survival of DA neurons (tyrosine hydroxylase immunoreactivity) in grafted striatum of pfVM+OECs group. Furthermore, pfVM+OECs group has less immune response (CD3+ T cells and OX-6+ microglia) around the grafted area compared with pfVM only group. These results suggest that OECs may enhance the survival of the striatal xenograftsvia dampeningtheimmune responseat the grafted sites. Using allogeneic OECs as a co-graft material for xenogeneic neural grafts could be a feasible therapeutic strategy to enhance results and applicability of the cell replacement therapy for PD.

Stable Intracerebral Transplantation of Neural Stem Cells for the Treatment of Paralysis Due to Ischemic Stroke.

NSI‐566 is a stable, primary adherent neural stem cell line derived from a single human fetal spinal cord and expanded epigenetically with no genetic modification. This cell line is being tested in clinical trials in the U.S. for treatment of amyotrophic lateral sclerosis and spinal cord injury. In a single‐site, phase I study, we evaluated the feasibility and safety of NSI‐566 transplantation for the treatment of hemiparesis due to chronic motor stroke and determined the maximum tolerated dose for future trials. Three cohorts (n = 3 per cohort) were transplanted with one‐time intracerebral injections of 1.2 × 107, 2.4 × 107, or 7.2 × 107 cells. Immunosuppression therapy with tacrolimus was maintained for 28 days. All subjects had sustained chronic motor strokes, verified by magnetic resonance imaging (MRI), initiated between 5 and 24 months prior to surgery with modified Rankin Scores [MRSs] of 2, 3, or 4 and Fugl‐Meyer Motor Scores of 55 or less. At the 12‐month visit, the mean Fugl‐Meyer Motor Score (FMMS, total score of 100) for the nine participants showed 16 points of improvement (p = .0078), the mean MRS showed 0.8 points of improvement (p = .031), and the mean National Institutes of Health Stroke Scale showed 3.1 points of improvement (p = .020). For six participants who were followed up for 24 months, these mean changes remained stable. The treatment was well tolerated at all doses. Longitudinal MRI studies showed evidence indicating cavity‐filling by new neural tissue formation in all nine patients. Although this was a small, one‐arm study of feasibility, the results are encouraging to warrant further studies. stem cells translational medicine 2019;8:999–1007

Roscovitine, an experimental CDK5 inhibitor, causes delayed suppression of microglial, but not astroglial recruitment around intracerebral dopaminergic grafts

Inhibitors of cell cycle proteins are known to reduce glial activation and to be neuroprotective in a number of settings. In the context of intracerebral grafting, glial activation is documented to correlate with graft rejection. However, the effects of modification of glial reactivity following grafting in the CNS are poorly understood. Moreover, it is not completely clear if the glial cells themselves trigger the rejection process, or are they secondarily activated.The present study investigated the effect of microglial inhibition by the cyclin-dependant kinase 5 (CDK5) inhibitor roscovitine following intracerebral transplantation in the rodent model of Parkinson's disease. Single cell suspension of rat E14 ventral mesencephalic tissue was transplanted to the dopamine-depleted striatum of unilaterally 6-hydroxydopamine (6-OHDA) lesioned male Sprague-Dawley rats. Experimental animals received injections of roscovitine (20 mg/kg) or a vehicle solution three times following the procedure. Immunohistochemistry was carried out on Day 7 and Day 28 to quantitatively describe the glial reaction adjacent to grafts.The data confirm that systemic roscovitine treatment significantly reduced microglial recruitment adjacent to the grafts on Day 28, without exhibiting significant effects on astroglia. However, this was not found to correlate with elevated numbers of neurons in the grafts. Moreover, microglial reaction surrounding grafts was less pronounced compared to control animals, subjected to the mechanical influence only, even without roscovitine treatment.Our results are the first to show the effect of cell cycle inhibition in the context of neuronal transplantation. The findings suggest that microglial activation around intracerebral grafts can be modified pharmacologically. However, the results do not confirm direct neuroprotective effects of cell cycle inhibition after intracerebral transplantation. Reducing microglial recruitment around grafts could be beneficial by reducing inflammation-related degenerative processes. Sparing astrocytes in the same time provides transplanted cells with essential trophics and support. We consider microglial inhibition to be a possible approach for reducing later graft-related complications.

Intracerebral transplantation of erythropoietin-producing fibroblasts facilitates neurogenesis and functional recovery in an ischemic stroke model.

IntroductionErythropoietin (EPO) can enhance neurogenesis and fibroblasts can secrete growth factors; together, they may benefit ischemic stroke. We transplanted EPO‐producing fibroblasts into the rodent infarcted brain to test their effect on neurogenesis and functional recovery.MethodsA total of 106 cells of EPO‐producing NIH/3T3 fibroblasts (EPO/EGFP/3T3) or enhanced green fluorescence protein (EGFP)‐expressing fibroblasts (EGFP/3T3) were stereotaxically injected into the infarcted striatum of adult rats that received transient middle cerebral artery occlusion (MCAO) surgery 1 day poststroke. On day 14 after MCAO, the animals were euthanized for the evaluation of neurogenesis via immunohistochemistry and of the expression of growth factors using enzyme‐linked immunosorbent assay. The infarct volume was analyzed using magnetic resonance imaging and the neurological behavior was assessed using the neurological severity scoring performed within 14 days after MCAO.ResultsThe MCAO rats with EPO/EGFP/3T3 treatment showed high EPO expression in the infarcted brain for at least 1 week. The concentration of brain‐derived neurotrophic factor was higher in both hemispheres of MCAO rats with either EGFP/3T3 or EPO/EGFP/3T3 treatment at 14 days poststroke compared with untreated MCAO rats. The number of Ki‐67‐, nestin‐, or doublecortin‐immunoreactive cells in bilateral subventricular zones was higher in EPO/EGFP/3T3‐treated MCAO rats than it was in untreated MCAO control animals, indicating the enhancement of neurogenesis after EPO/EGFP/3T3 treatment. Notably, post‐MCAO EPO/EGFP/3T3 treatment significantly reduced infarct size and improved functional recovery.ConclusionThe intracerebral transplantation of EPO‐producing fibroblasts benefited an ischemic stroke model probably via the enhancement of neurogenesis.

Cerebral Blood Flow in SHR Rats after Transplantation of Mesenchymal Stem Cells.

Intracerebral transplantation of mesenchymal stem cells to 6- and 12-month-old SHR rats induced angiogenesis in the pia mater. In 6-months-old SHR rats, perfusion in the brain tissue after cell transplantation considerably increased, while in 12-month-old rats it remained practically unchanged. We also observed marked activation of regulatory processes in the cerebral vascular system, most pronounced in 12-month-old rats. Neurogenic and myogenic tone of cerebral vessels increased significantly, while endothelium-dependent tone slightly decreased. The increase in neurogenic and myogenic tone of blood vessels in SHR rats at the age of 6 and 12 months after transplantation of stem cells can be explained by the formation of new smooth muscle cells in the pre-existing arteries walls. Greater muscle mass developed stronger force and contributed to narrowing of the arterial lumen, as a result, there was no increase in blood flow despite the downstream angiogenesis. A slight decrease in endothelium-dependent tone can be explained by increased production of vasodilators by newly formed endothelial cells.

Genetically engineered stem cell‐derived neurons can be rendered resistant to alpha‐synuclein aggregate pathology

Genetically engineered stem cell‐derived neurons can be rendered resistant to alpha‐synuclein aggregate pathology

Nonhypoxic pharmacological stabilization of Hypoxia Inducible Factor 1α: Effects on dopaminergic differentiation of human neural stem cells.

Parkinson's disease is a neurodegenerative disease resulting in degeneration of midbrain dopaminergic neurons. Exploratory studies using human foetal tissue or predifferentiated stem cells have suggested that intracerebral transplantation of dopaminergic precursor cells may become an effective treatment for patients with Parkinson's disease. However, strategies for dopaminergic stem cell differentiation vary widely in efficiency, and better methods still need to be developed. Hypoxia Inducible Factor 1 (HIF-1) is a transcription factor involved in the regulation of genes important for cellular adaption to hypoxia and low glucose supply. HIF-1 is to a large degree regulated by the availability of oxygen as in its presence, the subunit HIF-1α is degraded by HIF prolyl hydroxylase enzymes (HPHs). Stabilization of HIF-1α through inhibition of HPHs has been shown to increase dopaminergic differentiation of stem cells and to protect dopaminergic neurons against neurotoxins. This study investigated the effects of noncompetitive (FG-0041) and competitive (Compound A and JNJ-42041935) HIF-1α stabilizing compounds on the dopaminergic differentiation of human neural stem cells. Treatment with all HPH inhibitors at high oxygen tension (20%) resulted in HIF-1α stabilization as assessed by immunocytochemistry for HIF-1α and detection of increased levels of vascular endothelial growth factor in the conditioned culture medium. Following 10days of HIF-1α stabilization, the cultures displayed a slightly reduced proliferative activity and significantly increased relative levels of tyrosine hydroxylase-positive dopaminergic neurons. In conclusion, HIF-1α stabilization may represent a promising strategy for the generation of dopaminergic neurons intended for use in experimental in vitro studies and cell replacement therapies.