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We retrospectively studied the T2 star (T2*)-weighted magnetic resonance imaging (MRI) of a 40-year-old patient diagnosed with symptomatic early-onset cerebral amyloid angiopathy (CAA), occurring 34 years following childhood neurosurgery using a cadaveric dural patch. Our findings revealed that CAA associated with cadaveric dural transplantation could progress rapidly, sometimes with bilateral bleeding. This microbleed evolution is suggestive of water-soluble amyloid-β transmission via cerebrospinal fluid alongside perivascular drainage pathways with deposition in the cerebral artery walls due to clearance disturbances. Multiple intracerebral hemorrhages associated with CAA with a childhood cadaveric dural graft should be considered a life-threatening medical complication.

Stroke, traumatic brain injuries, and other similar conditions often lead to significant loss of functional brain tissue and associated disruption of neuronal signaling. A common strategy for replacing lost neurons is the injection of dissociated neural stem cells or differentiated neurons. However, this method is unlikely to be suitable for replacing large brain cavities, and the resulting distribution of neurons may lack the necessary architecture to support appropriate brain function. Engineered neural tissues may be a viable alternative. Cell death is a prominent concern in neuronal grafting studies, a problem that could be magnified with the transplantation of engineered neural tissues. Here, we examined the effect of one contributor to cell death, acute cerebral inflammation, on neuronal survival after the transplantation of bioengineered constructs based on silk scaffolds. We found evidence of a high degree of inflammation and poor neuronal survival after introducing engineered constructs into the motor cortex of rats. Integrating a corticosteroid (methylprednisolone) into the constructs resulted in significantly improved neuron survival during the acute phase of inflammation. The improved construct survival was associated with decreased markers of inflammation and an anti-inflammatory state of the immune system due to the steroid treatment., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

Dura mater graft-associated Creutzfeldt-Jakob disease (dCJD) can be divided into two subgroups that exhibit distinct clinical and neuropathological features, with the majority represented by a non-plaque-type of dCJD (np-dCJD) and the minority by a plaque-type of dCJD (p-dCJD). The two distinct phenotypes of dCJD had been considered to be unrelated to the genotype (methionine, M or valine, V) at polymorphic codon 129 of the PRNP gene or type (type 1 or type 2) of abnormal isoform of prion protein (PrPSc) in the brain, while these are major determinants of clinicopathological phenotypes of sporadic CJD (sCJD). The reason for the existence of two distinct subgroups in dCJD had remained elusive. Recent progress in research of the pathogenesis of dCJD has revealed that two distinct subgroups of dCJD are caused by infection with different PrPSc strains from sCJD, i.e., np-dCJD caused by infection with sCJD-MM1/MV1, and p-dCJD caused by infection with sCJD-VV2 or -MV2. These studies have also revealed previously unrecognized problems as follows: (i) the numbers of p-dCJD patients may increase in the future, (ii) the potential risks of secondary infection from dCJD, particularly from p-dCJD, may be considerable, and (iii) the effectiveness of the current PrPSc decontamination procedures against the PrPSc from p-dCJD is uncertain. To prevent secondary infection from p-dCJD, the establishment of effective decontamination procedures is an urgent issue. In this review, we summarize the past and future problems surrounding dCJD.

Huntington's disease (HD) is a fatal autosomal dominant neurodegenerative disease involving progressive motor, cognitive and behavioural decline, leading to death approximately 20 years after motor onset. The disease is characterised pathologically by an early and progressive striatal neuronal cell loss and atrophy, which has provided the rationale for first clinical trials of neural repair using fetal striatal cell transplantation. Between 2000 and 2003, the 'NEST-UK' consortium carried out bilateral striatal transplants of human fetal striatal tissue in five HD patients. This paper describes the long-term follow up over a 3-10-year postoperative period of the patients, grafted and non-grafted, recruited to this cohort using the 'Core assessment program for intracerebral transplantations-HD' assessment protocol. No significant differences were found over time between the patients, grafted and non-grafted, on any subscore of the Unified Huntington's Disease Rating Scale, nor on the Mini Mental State Examination. There was a trend towards a slowing of progression on some timed motor tasks in four of the five patients with transplants, but overall, the trial showed no significant benefit of striatal allografts in comparison with a reference cohort of patients without grafts. Importantly, no significant adverse or placebo effects were seen. Notably, the raclopride positron emission tomography (PET) signal in individuals with transplants, indicated that there was no obvious surviving striatal graft tissue. This study concludes that fetal striatal allografting in HD is safe. While no sustained functional benefit was seen, we conclude that this may relate to the small amount of tissue that was grafted in this safety study compared with other reports of more successful transplants in patients with HD.

There is a major unmet need for therapies for Parkinson's disease (PD) that go beyond treating symptoms and instead modify the course of the disease. The use of neural transplantation to repair the degenerating dopaminergic nigrostriatal pathway is one strategy by which this might be achieved. A series of small, independent open-label studies initially reported beneficial effects in patients treated with cell transplants derived from the fetal ventral mesencephalon. However, this initial promise was subsequently tempered by negative results from two larger, randomized studies, and the emergence of complications related to the procedure. The reason for these discordant results has been debated and this has led to the development of a new, multicenter, collaborative study--TRANSEURO--which will ultimately herald the next generation of clinical trials of cell therapy in PD, including those involving stem cells. In this chapter, we discuss what has been learned from previous studies of neural transplantation and go on to consider how relevant disease-modifying effects could be demonstrated in PD. We then go on to discuss how the design of future trials of transplantation-based therapies might be better conceived and executed., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Recent clinical and preclinical data are shedding greater light on the nuances of transplantation of fetal tissue for the treatment of Parkinson's disease. The field was brought to a halt by the development of abnormal involuntary movements directly linked to the graft at the turn of the century. Since then, there has been further analysis of transplanted patients, the development of an animal model, and extensive preclinical experimentation to clarify the activity of the graft and examine closely its interactions with the host environment and the direct consequences for L-DOPA- and graft-induced dyskinesia. This review brings together the latest clinical and preclinical findings on the impact of transplantation on both L-DOPA- and graft-induced dyskinesia., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Purpose of Review: We identify the major recent advances in sourcing, preparation and delivery of primary and stem cell transplants into the brain, the preclinical studies in animal models and preliminary results on feasibility, safety and efficacy in an increasing range of human neurodegenerative diseases., Recent Findings: After a decade of debate concerning the reliability and safety of foetal cell transplantation in Parkinson's and Huntington's diseases, the conditions for eliminating side-effects and achieving more consistent efficacy are being implemented in renewed trials. In parallel, rapid advances are being made in identifying alternative sources of stem cells for transplantation, establishing the protocols for their reliable differentiation into specific neuronal phenotypes and translating these novel sources to cell therapy for patients in new clinical trials. Objective assessment of efficacy in patients does not always reveal outcomes that are as impressive as claimed - either in the preclinical animal models or by many commercial stem cell clinics - and even when stem cell therapies do appear to have been validated, the mechanisms are not always clear., Summary: In spite of rapid progress, the conditions for reliable, well tolerated and effective cell therapies in brain disease are not yet fully established.

Graft-induced dyskinesias are a serious complication after neural transplantation in Parkinson's disease. One patient with Parkinson's disease, treated with fetal grafts 14 years ago and deep brain stimulation 6 years ago, showed marked improvement of motor symptoms but continued to suffer from OFF-medication graft-induced dyskinesias. The patient received a series of clinical and imaging assessments. Positron emission tomography and single-photon emission computed tomography 14 years posttransplantation revealed an elevated serotonin/dopamine transporter ratio in the grafted striatum compatible with serotonergic hyperinnervation. Inhibition of serotonin neuron activity by systemic administration of a 5-HT(1A) agonist suppressed graft-induced dyskinesias. Our data provide further evidence that serotonergic neurons mediate graft-induced dyskinesias in Parkinson's disease. Achieving a normal striatal serotonin/dopamine transporter ratio following transplantation of fetal tissue or stem cells should be necessary to avoid the development of graft-induced dyskinesias., (Copyright © 2011 Movement Disorder Society.)

Background: This study evaluated surgical outcomes after endonasal septoplasty using caudal septal batten grafting for caudal septal deviation., Methods: Fifty-six patients completed questionnaires to assess nasal obstruction by telephone interviews 8-63 months postoperatively (12.2 months on the average). In addition, patients assessed the severity of nasal symptoms (i.e., mouth breathing, mouth dryness, hyposmia, rhinorrhea, epistaxis, trouble sleeping, snoring, and being concerned about nasal problems) preoperatively and postoperatively using a visual analog scale (VAS). These VAS scores were compared with those of patients who underwent endonasal septoplasty using the cutting and suture technique. Complications were analyzed., Results: Thirty-four (60.7%) patients reported their nasal obstruction was much improved, 17 (30.3%) reported their condition was improved, and 5 (8.9%) reported no change postoperatively. Patients reported a decrease in severity of all nasal symptoms (p < 0.05 for each). Their nasal obstruction improvement was not significantly different from that of patients managed by the cutting and suture technique. Complications after surgery included hyposmia in two cases, small septal perforation in one case, chondritis in one case, and septal abscess in one case, and all were managed successfully. No patient required revision septoplasty due to recurrence during the follow-up period., Conclusion: Endonasal septoplasty using caudal septal batten grafting for caudal septal deviation resulted in improvement in nasal obstruction and nasal symptoms and was associated with an acceptable complication rate.

The use of allogeneic fetal neural precursor cells (NPCs) as a cell replacement therapy in neurodegenerative disorders holds great promise. However, previous studies concerning the possibility of alloimmune rejection of the transplanted cells have been inconclusive. Here, we used flow cytometry to quantify the expression of major histocompatibility complex (MHC) molecules by human NPCs, obtained from the cortex or ventral mesencephalon of fetuses with gestational ages between 7 and 11 weeks. MHC class I was undetectable on the surface of freshly isolated primary fetal tissue from either location, but increased over time in proliferating NPC cultures; after 7days in vitro, MHC class I was detectable on most cells. Following differentiation, MHC class I expression persisted on non-neuronal cells. MHC class II levels remained low at all time points but were inducible by pro-inflammatory cytokines, whereas the co-stimulatory molecules, CD80 and CD86, remained undetectable. Nonetheless, CD4+ and CD8+ T cells proliferated when peripheral blood mononuclear cells (PBMCs) were cultured with allogeneic NPCs. Weaker responses were obtained when NPCs were co-cultured with purified allogeneic responder T cells, suggesting that indirect allorecognition contributed significantly to PBMC responses. In conclusion, differentiating human NPCs are immunogenic in vitro, suggesting that they may trigger immune rejection unless transplant recipients are immunosuppressed., (Copyright © 2010 Elsevier Inc. All rights reserved.)

Clinical trials evaluating transplantation of fetal tissue for the treatment of Parkinson's disease identified the unexpected side effect of abnormal movements in the 'off'l-DOPA state. Termed graft-induced dyskinesia (GID), various hypotheses have been put forward as to their cause but unfortunately the significant differences in clinical trial protocols and lack of a truly representative animal model has hindered the search for a conclusive basis for their appearance. Likely causative factors have been identified through careful examination of patient data and the use of amphetamine-induced dyskinesia in a rodent model of Parkinson's disease. New trials being planned in Europe hope to avoid GID, whilst maximizing on the functional benefit that can be afforded by this treatment approach but questions still remain as to the underlying mechanism., (Copyright © 2011 Elsevier Inc. All rights reserved.)

The treatment of Parkinson's disease with grafts of fetal ventral mesencephalic tissue has shown some success, but can result in graft-induced dyskinesias (GIDs). Recently in Science Translational Medicine, Politis et al. (2010) demonstrate that GIDs may originate from serotoninergic neurons that are cografted in these transplants., (Copyright 2010 Elsevier Inc. All rights reserved.)

Purpose of Review: We review recent experiments conducted using embryonic tissue and stem cell transplants in experimental models of Parkinson's disease. We also highlight the challenges which remain to be met in order for cell therapy to become clinically effective and safe., Recent Findings: The outcome of previous clinical transplantation trials was variable in terms of motor recovery. We discuss whether transplants can mitigate L-3,4-dihydroxyphenylalanine (L-DOPA)-induced dyskinesias and consider the risk factors which predispose to graft-induced dyskinesias. In addition, we introduce Transeuro, a new European Union-funded multicenter consortium which plans to perform transplantation trials.Stem cells have emerged as an alternative source for the generation of dopaminergic precursors. We briefly outline progress made in the use of human embryonic stem cells and focus predominantly on the emerging field of induced pluripotency. We conclude by introducing the exciting and novel method of direct reprogramming which involves the conversion of fibroblasts to neurons without inducing a pluripotent state., Summary: The area of cell transplantation has been revitalized by the identification of parameters which predispose patients to graft-induced dyskinesias and by the emergence of novel methods of generating dopaminergic neurons. Hopefully, the Transeuro clinical trials will give further impetus and act as a stepping stone to future trials employing stem-cell-derived neurons.

Functional imaging has provided objective evidence that human fetal ventral mesencephalic tissue implanted in the striatum of Parkinson's disease patients can survive, grow, release dopamine, normalize brain metabolism, and restore striatal-cortical connections. Open-label clinical trials have shown robust clinical improvement in several PD patients but these results were not replicated in two double-blind sham-surgery controlled clinical trials. Graft-induced dyskinesias are serious adverse effects and a major roadblock for the further development of cell therapies, and functional imaging can help investigate the mechanisms underlying their cause. Functional imaging can also aid future trials by improving patient selection, assessing restoration of brain connectivity, and monitor inflammatory processes. Although functional imaging cannot currently be used as a primary endpoint in clinical transplantation trials, it can provide additional valuable information alongside clinical observations., (Copyright © 2010 Elsevier B.V. All rights reserved.)

The development of neural transplantation as a treatment for Parkinson's disease has been compromised by a lack of functional efficacy and the appearance of transplant-induced motor side-effects in some patients. Since the first reports of these graft-induced dyskinesias (GID), and the realization of their impact on the progress of the field, a great deal of experimental work has been performed to determine the underlying cause(s) of this problematic side-effect. In this review we describe the clinical phenomenon of GID, explore the different representations of GID in rodent models, and examine the various hypotheses that have been postulated to be the cause. Based on the available clinical and preclinical data we outline strategies to avoid GID in future clinical trials using fetal cell transplants or cell preparations derived from stem cells., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Neural transplantation has emerged as a possible therapy for Parkinson's disease (PD). Clinical studies performed during the 1990s, where dopaminergic neurons derived from the human embryonic brain were transplanted into striatum of patients with PD, provided proof-of-principle that long-lasting therapeutic benefits can be achieved. Subsequent studies, in particular two that followed a double-blind, sham surgery, placebo-control design, showed variable and mostly negative results. They also revealed that some patients develop involuntary movements, so called graft-induced dyskinesias, as side effects. Thus, while nigral transplants clearly work well in select PD cases, the technique needs refinement before it can successfully be performed in a large series of patients. In this review, we describe the clinical neural transplantation trials in PD and the likely importance of factors such as patient selection, trial design, preparation of the donor tissue, and surgical techniques for successful outcome and avoiding unwanted side effects. We also highlight that it was recently found that neuropathological signs typical for PD can appear inside some of the grafted neurons over a decade after surgery. Finally, we discuss future possibilities offered by stem cells as potential sources of dopamine neurons that can be used for transplantation in PD., (Copyright © 2010 Elsevier B.V. All rights reserved.)

Treatment-induced motor complications represent a major clinical problem in Parkinson's disease (PD). Pharmacological dopamine (DA) replacement with l-dopa causes motor fluctuations and abnormal involuntary movements (dyskinesia) in the vast majority of the patients. Intrastriatal grafts of embryonic dopaminergic neurons can cause dyskinesia too, as shown by clinical trials of neural transplantation in PD. Animals models of these complications can be produced in rats and mice in which the nigrostriatal DA pathway has been severely damaged. Rodent models allow investigators to explore mechanistic hypotheses at the cellular and molecular level. Moreover, the rat model of L-dopa-induced abnormal involuntary movements shows both face validity and predictive validity relative to the corresponding disorder in primates, and provides a cost effective tool to evaluate novel antidyskinetic interventions. This article reviews the strategies that have been used to reproduce different motor complications of PD treatment in rodents, and comments on their range of applicability., (Copyright 2009 Elsevier Ltd. All rights reserved.)

Up to February 2008, a total of 132 patients with dura mater graft-associated Creutzfeldt-Jakob disease (dCJD) have been identified in Japan, accounting for a majority of the world's patients with dCJD. The patients received dura mater grafts from 1978 to 1993. Lyodura (B. Braun, Melsungen, Germany) was used for all the patients in whom the brand name of the dura mater could be identified. After the incubation period of 1 to 25 years (mean, 11.8 years), CJD appeared from 1985 through to 2006. We analyzed clinical, pathological, and molecular features in 74 patients with dCJD who had been prospectively registered by the CJD Surveillance Committee. The cases of dCJD could be classified into two distinct clinicopathological phenotypes: a non-plaque type, showing typical features identical with those of classic CJD, and a plaque type, characterized by atypical features, including slow progression, lack of or late occurrence of periodic sharp wave complexes on EEG, and plaque formation in the brain. The plaque type accounted for one-third of the pathologically confirmed or clinically diagnosed cases of dCJD. The non-plaque type was associated with methionine homozygosity at codon 129 (129M/M) of the PrP gene in all patients, except for in one patient with the 129M/valine (V) genotype and type 1 protease-resistant PrP (PrP(res)), whereas the plaque type was always associated with the 129M/M genotype and the intermediate type between types 1 and 2 of PrP(res) in all cases. Thus, the clinicopathological and molecular features of the plaque type are distinct from those of the non-plaque type, suggesting contamination of the dura mater grafts with different prion strains.

In some patients, graft-induced dyskinesia develops following intrastriatal transplantation of embryonic neural tissue for the treatment of Parkinson's disease. The mechanisms underlying these involuntary movements need to be clarified before this approach to clinical cell therapy can be developed further. We previously found that rats with 6-OHDA lesions, primed with L-DOPA treatment and that have subsequently undergone intrastriatal graft surgery exhibit involuntary movements when subjected to amphetamine. This model of amphetamine-induced AIMs reflects a pattern of post-graft behaviours that in the absence of robust spontaneous GID in the rat is the closest approximation that we currently have available. We now show that they are associated with the chronic administration of L-DOPA prior to the transplantation surgery. We also demonstrate that neither changes in c-fos nor FosB/DeltaFosB expression in the lateral striatum are associated with the expression of these behaviours. Taken together, these data reveal that the severity of abnormal movements elicited by amphetamine in grafted animals may relate to previous L-DOPA exposure and dyskinesia development, but they develop through mechanisms that are independent of FosB/DeltaFosB upregulation.

Recent studies have found that cellular self-renewal capacity in brain cancer is heterogeneous, with only stem-like cells having this property. A link between adult stem cells and cancer stem cells remains, however, to be shown. Here, we describe the emergence of cancer stem-like cells from in vitro cultured brain stem cells. Adult rat subventricular zone (SVZ) stem cells transformed into tumorigenic cell lines after expansion in vitro. These cell lines maintained characteristic features of stem-like cells expressing Nestin, Musashi-1 and CD133, but continued to proliferate upon differentiation induction. Karyotyping detected multiple acquired chromosomal aberrations, and syngeneic transplantation into the brain of adult rats resulted in malignant tumor formation. Tumors revealed streak necrosis and displayed a neural as well as an undifferentiated phenotype. Deficient downregulation of platelet-derived growth factor (PDGF) receptor alpha was identified as candidate mechanism for tumor cell proliferation, and its knockdown by siRNA resulted in a reduction of cell growth. Our data point to adult brain precursor cells to be transformed in malignancies. Furthermore, in vitro expansion of adult neural stem cells, which will be mandatory for therapeutic strategies in neurological disorders, also harbors the risk for amplifying precursor cells with acquired genetic abnormalities and induction of malignant tumors after transplantation.

The prospect of using cell-based interventions (CBIs) to treat neurological conditions raises several important ethical and policy questions. In this target article, we focus on issues related to the unique constellation of traits that characterize CBIs targeted at the central nervous system. In particular, there is at least a theoretical prospect that these cells will alter the recipients' cognition, mood, and behavior-brain functions that are central to our concept of the self. The potential for such changes, although perhaps remote, is cause for concern and careful ethical analysis. Both to enable better informed consent in the future and as an end in itself, we argue that early human trials of CBIs for neurological conditions must monitor subjects for changes in cognition, mood, and behavior; further, we recommend concrete steps for that monitoring. Such steps will help better characterize the potential risks and benefits of CBIs as they are tested and potentially used for treatment.

A high percentage of patients with temporal lobe epilepsy (TLE) are refractory to conventional pharmacotherapy. The progressive neurodegenerative processes associated with a lifetime of uncontrolled seizures mandate the development of alternative approaches to treat this disease. Transplantation of inhibitory cells has been suggested as a potential therapeutic strategy to achieve seizure suppression in humans with intractable TLE. Preclinical investigations over 20 years have demonstrated that multiple cell types from several sources can produce anticonvulsant, and antiepileptogenic, effects in animal models of TLE. Transplanting GABA-producing cells, in particular, has been shown to reduce seizures in several well-established models. This review addresses experimentation using different sources of transplantable GABAergic cells, highlighting progress with fetal tissue, neural cell lines, and stem cells. Regardless of the source of the GABAergic cells used in seizure studies, common challenges have emerged. Several variables influence the anticonvulsant potential of GABA-producing cells. For example, tissue availability, graft survival, immunogenicity, tumorigenicity, and varying levels of cell migration, differentiation, and integration into functional circuits and the microenvironment provided by sclerotic tissue all contribute to the efficacy of transplanted cells. The challenge of understanding how all of these variables work in concert, in a disease process that has no well-established etiology, suggests that there is still much basic research to be done before rational cell-based therapies can be developed for TLE.

Objective: Iatrogenic Creutzfeldt-Jakob disease (iCJD) is mainly associated with dura mater (DM) grafts and administration of human growth hormones (hGH). Data on disease course in DM-CJD are limited. We describe the clinical and diagnostic findings in this patient group with special emphasis on MRI signal alterations., Methods: Ten DM-CJD patients were studied for their clinical symptoms and diagnostic findings. The MRIs were evaluated for signal increase of the cortical and subcortical structures., Results: DM-CJD patients had a median incubation time of 18 years and median disease duration of 7 months. The majority of patients were MM homozygous at codon 129 of the prion protein gene (PRNP) and presented with gait ataxia and psychiatric symptoms. No correlation between the graft site and the initial disease course was found. The MRI showed cortical and basal ganglia signal increase each in eight out of ten patients and thalamic hyperintensity in five out of ten cases. Of interest, patients with thalamic signal increase were homozygous for methionine., Conclusion: The MRI findings in DM-CJD largely resemble those seen in sporadic CJD, as the cortex and basal ganglia are mainly affected.

The observation that neural grafts can induce dyskinesias has severely hindered the development of a transplantation therapy for Parkinson's disease (PD). We addressed the hypothesis that inflammatory responses within and around an intrastriatal graft containing dopamine neurons can trigger dyskinetic behaviors. We subjected rats to unilateral nigrostriatal lesions with 6-hydroxydopamine (6-OHDA) and treated them with L-DOPA for 21 days in order to induce abnormal involuntary movements (AIMs). Subsequently, we grafted the rats with allogeneic embryonic ventral mesencephalic tissue in the dopamine-denervated striatum. In agreement with earlier studies, the grafted rats developed dyskinesia-like AIMs in response to amphetamine. We then used two experimental approaches to induce an inflammatory response and examined if the amphetamine-induced AIMs worsened or if spontaneous AIMs developed. In one experiment, we challenged the neural graft hosts immunologically with an orthotopic skin allograft of the same genetic origin as the intracerebral neural allograft. In another experiment, we infused the pro-inflammatory cytokine interleukin 2 (IL-2) adjacent to the intrastriatal grafts using osmotic minipumps. The skin allograft induced rapid rejection of the mesencephalic allografts, leading to disappearance of the amphetamine-induced AIMs. Contrary to our hypothesis, the rejection process itself did not elicit AIMs. Likewise, the IL-2 infusion did not induce spontaneous AIMs, nor did it alter L-DOPA-induced AIMs. The IL-2 infusions did, however, elicit the predicted marked striatal inflammation, as evidenced by the presence of activated microglia and IL2Ralpha-positive cells. These results indicate that an inflammatory response in and around grafted dopaminergic neurons is not sufficient to evoke dyskinetic behaviors in experimental models of PD.

Transplantations of olfactory ensheathing cells (OECs) have been reported to promote axonal regeneration and functional recovery after spinal cord injury, but have demonstrated limited growth promotion of rat rubrospinal axons after a cervical dorsolateral funiculus crush. Rubrospinal neurons undergo massive atrophy after cervical axotomy and show only transient expression of regeneration-associated genes. Cell body treatment with brain-derived neurotrophic factor (BDNF) prevents this atrophy, stimulates regeneration-associated gene expression and promotes regeneration of rubrospinal axons into peripheral nerve transplants. Here, we hypothesized that the failure of rubrospinal axons to regenerate through a bridge of OEC transplants was due to this weak intrinsic cell body response. Hence, we combined BDNF treatment of rubrospinal neurons with transplantation of highly enriched OECs derived from the nasal mucosa and assessed axonal regeneration as well as behavioral changes after a cervical dorsolateral funiculus crush. Each treatment alone as well as their combination prevented the dieback of the rubrospinal axons, but none of them promoted rubrospinal regeneration beyond the lesion/transplantation site. Motor performance in a food-pellet reaching test and forelimb usage during vertical exploration (cylinder test) were more impaired after combining transplantation of OECs with BDNF treatment. This impaired motor performance correlated with lowered sensory thresholds in animals receiving the combinatorial therapy - which were not seen with each treatment alone. Only this combinatorial treatment group showed enhanced sprouting of calcitonin gene-related peptide-positive axons rostral to the lesion site. Hence, some combinatorial treatments, such as OECs with BDNF, may have undesired effects in the injured spinal cord.

Neuropathological changes in Parkinson's disease progress slowly and spread according to a characteristic pattern. Recent papers have shed light on this progression of pathology by examining the fate of neurons grafted into the brains of patients with Parkinson's disease. Two of these studies demonstrate that grafted healthy neurons can gradually develop the same pathology as host neurons in the diseased brains. According to these studies, implanted neurons developed alpha-synuclein- and ubiquitin-positive Lewy bodies more than a decade after transplantation. We discuss the possible underlying mechanisms and their implications for how pathology spreads in Parkinson's disease.

Neural transplantation has been investigated experimentally and clinically for the purpose of developing new treatment options for intractable epilepsy. In the present study we assessed the anticonvulsant efficacy and safety of bilateral allotransplantation of genetically engineered striatal GABAergic rat cell lines into the substantia nigra pars reticulata (SNr). Rats with previously-established seizures, induced by amygdala kindling, were used as a model of temporal lobe epilepsy. Three cell lines were transplanted: (1) immortalized GABAergic cells (M213-2O) derived from embryonic rat striatum; (2) M213-2O cells (CL4) transfected with human GAD67 cDNA to obtain higher GABA synthesis than the parent cell line; and (3) control cells (121-1I), also derived from embryonic rat striatum, but which did not show GAD expression. A second control group received injections of medium alone. Transplantation of M213-2O cells into the SNr of kindled rats resulted in significant but transient anticonvulsant effects. Neither control cells nor medium induced anticonvulsant effects. Strong tissue reactions were, however, induced in the host brain of kindled but not of non-kindled rats, and only in animals that received grafts of genetically modified CL4 cells. These tissue reactions included graft rejection, massive infiltration of inflammatory immune cells, and gliosis. The anticonvulsant effect of M213-2O cells emphasizes the feasibility of local manipulations of seizures by intranigral transplantation of GABA-producing cells. On the other hand, the present data suggest that kindling-induced activation of microglia in the SNr can enhance immune reactions to transplanted cells. In this case, under conditions of further immunological stimulation by CL4 cells, transfected with a human cDNA, substantial immune reactions occurred. Thus, it appears that the condition of the host brain and the production of foreign proteins by transplanted cells have to be considered in estimating the risks of rejection of transplants into the brain.

We present five cases of dura mater-associated Creutzfeldt-Jakob disease (dura-CJD) that were analyzed clinicopathologically and review previous reports. The average age at dura mater transplantation was 54.4 +/- 7.3 years, and the average age at CJD onset was 66.0 +/- 8.2 years, with an average latency period of 11.6 +/- 1.1 years. The average age at death was 67.6 +/- 8.7 years, with an average CJD disease duration of 16.8 +/- 10.4 months. Symptoms of CJD onset in four patients who received dura mater transplantation below the cerebellar tent reflected cerebellar or brainstem dysfunction, whereas symptoms of one patient who received transplantation above the cerebellar tent reflected cerebral cortical involvement. All patients showed rapidly progressive cognitive impairment, and both periodic sharp-wave complexes on electroencephalogram and myoclonus were observed in the early disease stage. Neuropathologic evaluation showed one case of subacute spongiform encephalopathy and four cases of panencephalopathic-type CJD. Widespread cerebral neocortical, subcortical gray matter and cerebellar cortical involvement were observed to varying degrees, and severity tended to be associated with CJD disease duration. There were no instances of kuru plaques or florid plaques. Prion protein (PrP) immunostaining showed widespread synaptic-type PrP deposition. No differences between our dura-CJD cases and typical cases of sporadic CJD were found with respect to clinicopathologic findings, except history of dura mater transplantation. Although a specific association between the dura mater graft site and neuropathologic observations was not evaluated in the present study, the initial symptoms appear to be closely related to the graft site, indicating a direct transmission of CJD from the graft site to the adjacent brain.

Parkinson's disease (PD) is a common neurological disorder of the brain which has as a part of its core pathology the progressive degeneration of the dopaminergic nigrostriatal pathway. Therefore, cell therapies that aim to restore this degenerated dopaminergic network represent a promising strategy in helping to cure PD. In this review, the authors start by discussing the progress of research on the use of fetal ventral mesencephalic (VM) tissue in transplantation therapies in PD, both from the clinical and experimental perspectives. Then the issues pertinent to its adoption in the clinic are discussed, including the ethical and practical problems with its use, the varied composition of VM tissue that is implanted with the graft and how this may account for some of the problems seen in the clinical trials using this tissue, especially graft-induced dyskinesia. Finally other promising sources of tissue for PD cell therapy are described, including mesenchymal and embryonic stem cells, before concluding on what is the best approach to the cellular repair of the parkinsonian brain.

Clinical trials in patients with Parkinson's disease have shown that transplants of fetal mesencephalic dopamine neurons can form a new functional innervation of the host striatum, but the clinical benefits have been highly variable: some patients have shown substantial recovery in motor function, whereas others have shown no improvement and even a worsening in the 3,4-dihydroxyphenyl-L-alanine (L-DOPA)-induced dyskinetic side effects. Differences in the composition of the grafted cell preparation may contribute to these discrepancies. In particular, the number of serotonin neurons contained in the graft can vary greatly depending on the dissection of the fetal tissue. Importantly, serotonin neurons have the ability to store and release dopamine, formed from exogenously administered L-DOPA. Here, we have evaluated the effect of transplants containing serotonin neurons, or a mixture of dopamine and serotonin neurons, on L-DOPA-induced dyskinesias in 6-hydroxydopamine-lesioned animals. As expected, dopamine neuron-rich grafts induced functional recovery, accompanied by a 60% reduction in L-DOPA-induced dyskinesia that developed gradually over the first 10 weeks. Rats with serotonin-rich grafts with few dopamine neurons, in contrast, showed a progressive worsening of their L-DOPA-induced dyskinesias over time, and no functional improvement. The antidyskinetic effect of dopamine-rich grafts was independent of the number of serotonin neurons present. We conclude that serotonin neurons in the grafts are likely to have a detrimental effect on L-DOPA-induced dyskinesias in cases in which the grafts contain no or few dopamine neurons.

Background: A subset of patients with dura mater graft-associated Creutzfeldt-Jakob disease (dCJD) demonstrates atypical clinical features and plaque formation in the brain (plaque type)., Objective: To elucidate the frequency and clinical features of plaque type dCJD in comparison with the non-plaque type., Methods: We analyzed clinicopathologic findings of 66 patients who had been registered as having dCJD by the Creutzfeldt-Jakob Disease Surveillance Committee, Japan, between April 1999 and February 2006., Results: 1) Analysis of pathologically confirmed dCJD patients (n = 23) demonstrated plaque type dCJD in 11 patients (48%). In contrast to the non-plaque type with classic CJD features, the plaque type commonly presented with ataxic gait as an initial manifestation, relatively slow progression of neurologic symptoms, and no or late occurrence of periodic sharp-wave complexes (PSWCs) on EEG. MRI, especially diffusion-weighted images, and CSF 14-3-3 protein and neuron specific enolase (NSE) showed high diagnostic sensitivities for plaque as well as non-plaque types. 2) Analysis of clinically diagnosed dCJD patients (n = 34) demonstrated that 7 patients (21%) had atypical clinical features without PSWCs, probably corresponding to plaque type dCJD., Conclusion: The frequency of the plaque type in dura mater graft-associated Creutzfeldt-Jakob disease is apparently higher than previously recognized. For the clinical diagnosis of the plaque type dura mater graft-associated Creutzfeldt-Jakob disease, MRI and CSF markers would be useful, in addition to the core features, i.e., onset with ataxic gait disturbance, relatively slow progression, and no or late occurrence of periodic sharp-wave complexes on EEG.

The therapeutic potential of embryonic stem (ES) cells in neurodegenerative disorders has been widely recognized, and methods are being developed to optimize culture conditions for enriching the cells of interest and to improve graft stability and safety after transplantation. Whereas teratoma formation rarely occurs in xenogeneic transplantation paradigms of ES cell-derived neural progeny, more than 70% of mice that received murine ES cell-derived neural precursor cells develop teratomas, thus posing a major safety problem for allogeneic and syngeneic transplantation paradigms. Here we introduce a new differentiation protocol based on the generation of substrate-adherent ES cell-derived neural aggregates (SENAs) that consist predominantly of neuronally committed precursor cells. Purified SENAs that were differentiated into immature but postmitotic neurons did not form tumors up to four months after syngeneic transplantation into the acutely degenerated striatum and showed robust survival.

Intrastriatal transplants of embryonic ventral mesencephalon can cause dyskinesia in patients with Parkinson's disease (PD). We assessed the impact of transplant size on the development of graft-induced dyskinesia. Rats with unilateral 6-hydroxydopamine lesions were primed to exhibit L-DOPA-induced dyskinesia. They were then intrastriatally grafted with different quantities of embryonic ventral mesencephalic tissue to give small and large grafts. Without drug treatment, discrete dyskinetic-like movements were observed in most rats with large grafts 2-6 weeks after transplantation, but disappeared later. Amphetamine evoked severe abnormal involuntary movements (AIMs) in grafted animals, which were more striking with large grafts. The AIMs coincided with contralateral rotation, but displayed a different temporal profile and pharmacological properties. Thus, selective dopamine uptake blockade elicited rotational behavior, whereas coadministration of both dopamine and serotonin uptake blockers was required to evoke significant orolingual and limb AIMs. In conclusion, robust and reproducible AIMs were evoked in rats with large grafts by blockade of monoamine reuptake. These AIMs may provide a new tool for assessing dyskinetic effects of neural grafting.

In two recent double-blind clinical trials of fetal ventral mesencephalic cell transplants into the striatum in patients with Parkinson's disease (PD), a significant proportion of the grafted patients developed dyskinetic side effects, which were not seen in the sham operated patients. Comparison between dyskinetic and non-dyskinetic grafted patients in one of the trials suggested that an uneven pattern of striatal reinnervation might be the leading cause of the dyskinesias. Here, we studied the importance of graft placement for the development of dyskinesias in parkinsonian rats. Abnormal involuntary movements resembling peak-dose dyskinesias seen in PD patients were induced by daily injections of L-DOPA for 6 weeks. The dyskinetic animals received about 130.000 fetal ventral mesencephalic cells as single grafts placement in the rostral or the caudal aspect of the head of striatum. The results show that grafts placed in the caudal, but not the rostral, part are effective in reducing the L-DOPA-induced limb and orolingual dyskinesia, predominantly seen as hyperkinesia. The same grafts, however, also induced a new type of dyskinetic behavior after activation with amphetamine, which were not seen in non-grafted lesion controls. The severity of these abnormal involuntary movements was significantly correlated with a higher graft-derived dopaminergic reinnervation in the caudal aspect of the head of striatum relative to the rostral part. The results indicate that graft-induced dyskinesias in PD patients may be linked to single, small graft deposits that provide an uneven, patchy reinnervation of the putamen.

A 9-year-old Japanese girl received a cadaveric dura mater graft during surgery following a head injury with brain contusion. She continued to do well, but when she became 19-years-old, she gradually showed a violent character and was treated in a psychiatric hospital. Another 6 years later, 200 months after the procedure, she developed a progressive gait ataxia, which subsequently led to her death within 10 months of onset. An autopsy showed she had CJD. This patient represents an atypical case of dura-associated CJD (dCJD) with unusual clinicopathological features including the late occurrence of myoclonus, an absence of periodic synchronous discharges in the electroencephalogram, and the presence of widespread florid plaques. However, our detection of an asymmetrical increase in the MRI-derived images of pulvinar nuclei has not been previously observed in other atypical cases of dCJD. Because atypical dCJD cases share several clinicopathological features with those of vCJD, and because asymmetrical hyperintense signals in the pulvinar have been observed in some neuropathologically confirmed vCJD cases, we had some difficulty in a differential diagnosis between atypical dCJD and vCJD. This is the first atypical dCJD case showing a pulvinar high signal compared with all other basal ganglia on MRI.

Dyskinesias are a common consequence of dopaminergic therapy in patients with Parkinson's disease. Little is known about the influence of cellular replacement strategies upon drug-induced dyskinesias. In the current study, we employed parkinsonian rats to test whether the distribution of dopamine neuron grafts could differentially alter striatal circuitry and levodopa-induced dyskinesias. Specifically, we compared behavioral and neurochemical consequences of dopamine reinnervation restricted to a focal region of the striatum to innervation encompassing the majority of the striatum by distributing the same number of cells into single locus or multiple locations. Both the single-site and widespread grafts reduced pregraft dyskinesias and normalized FosB/DeltaFosB in the dorsal two-thirds of the lateral striatum. However, single-site DA graft recipients developed a robust, novel forelimb-facial stereotypy and upregulated FosB/DeltaFosB expression in the ventrolateral striatum, an area associated with movements of tongue and forelimbs. The onset of forelimb-facial stereotypy correlated with measures of increased graft function.