Jun Takahashi

Kyoto University, Kioto, Kyōto, Japan

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Publications (147)472.58 Total impact

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    ABSTRACT: Survivors of pediatric brain tumors are often affected by late effects, such as motility disturbance of limb(s), seizure, ocular/visual impairment, endocrine abnormality, and higher brain dysfunction, resulting from the disease and its treatment. Appropriate provision of supportive care will require understanding the effects of these experiences on survivors' health-related quality of life (HRQOL). The aim of this study was to identify the relationships between late effects and specific aspects of the HRQOL of pediatric brain tumor survivors. We distributed questionnaires for measuring HRQOL to 138 survivors and their parents at 8 hospitals and 1 clinic in Japan and simultaneously surveyed late effects using information provided by the survivors' attending physicians. We compared the HRQOL of survivors with and survivors without specific late effects. A total of 106 survivors and their parents returned the questionnaires to the researchers. The HRQOL of survivors 18 years or older was negatively affected by all 5 late effects, indicating that their higher impairment was associated with diminished HRQOL. The HRQOL of survivors aged 12 to 17 years was negatively affected by 2 late effects (ocular/visual impairment and motility disturbance of the limbs). A part of the HRQOL subdomain (motor and cognitive functioning) of survivors aged 12 to 17 years was positively related to ocular/visual impairment. Five late effects influenced the HRQOL of pediatric brain tumor survivors. Nurses and other health professionals should provide specific care designed to support aspects of HRQOL affected by late effects. For example, survivors with ocular/visual impairment may be expected to require additional emotional support, and those with seizures or endocrine abnormalities may be expected to require additional support for sleep disorders.
    Cancer nursing 03/2014; · 1.88 Impact Factor
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    ABSTRACT: Human induced pluripotent stem cells (iPSCs) can provide a promising source of midbrain dopaminergic (DA) neurons for cell replacement therapy for Parkinson's disease. However, iPSC-derived donor cells inevitably contain tumorigenic or inappropriate cells. Here, we show that human iPSC-derived DA progenitor cells can be efficiently isolated by cell sorting using a floor plate marker, CORIN. We induced DA neurons using scalable culture conditions on human laminin fragment, and the sorted CORIN(+) cells expressed the midbrain DA progenitor markers, FOXA2 and LMX1A. When transplanted into 6-OHDA-lesioned rats, the CORIN(+) cells survived and differentiated into midbrain DA neurons in vivo, resulting in significant improvement of the motor behavior, without tumor formation. In particular, the CORIN(+) cells in a NURR1(+) cell-dominant stage exhibited the best survival and function as DA neurons. Our method is a favorable strategy in terms of scalability, safety, and efficiency and may be advantageous for clinical application.
    Stem cell reports. 03/2014; 2(3):337-50.
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    ABSTRACT: In order to apply human embryonic stem cells (hESCs) and induced pluripotent stem cells (hiPSCs) to regenerative medicine, the cells should be produced under restricted conditions conforming to GMP guidelines. Since the conventional culture system has some issues that need to be addressed to achieve this goal, we developed a novel culture system. We found that recombinant laminin-511 E8 fragments are useful matrices for maintaining hESCs and hiPSCs when used in combination with a completely xeno-free (Xf) medium, StemFit™. Using this system, hESCs and hiPSCs can be easily and stably passaged by dissociating the cells into single cells for long periods, without any karyotype abnormalities. Human iPSCs could be generated under feeder-free (Ff) and Xf culture systems from human primary fibroblasts and blood cells, and they possessed differentiation abilities. These results indicate that hiPSCs can be generated and maintained under this novel Ff and Xf culture system.
    Scientific Reports 01/2014; 4:3594. · 5.08 Impact Factor
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    ABSTRACT: We examined the gene expression and DNA methylation of 49 human induced pluripotent stem cells (hiPSCs) and 10 human embryonic stem cells and found overlapped variations in gene expression and DNA methylation in the two types of human pluripotent stem cell lines. Comparisons of the in vitro neural differentiation of 40 hiPSCs and 10 human embryonic stem cells showed that seven hiPSC clones retained a significant number of undifferentiated cells even after neural differentiation culture and formed teratoma when transplanted into mouse brains. These differentiation-defective hiPSC clones were marked by higher expression levels of several genes, including those expressed from long terminal repeats of specific human endogenous retroviruses. These data demonstrated a subset of hiPSC lines that have aberrant gene expression and defective potential in neural differentiation, which need to be identified and eliminated before applications in regenerative medicine.
    Proceedings of the National Academy of Sciences 11/2013; · 9.81 Impact Factor
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    ABSTRACT: Surgical intervention is expected to improve the quality of life in patients with intractable epilepsy by providing adequate seizure control. Although many previous studies showed various rates of seizure freedom, definite conclusions have not yet been made regarding outcomes. In order to clarify the long-term postoperative outcome for a period up to 10 years, a retrospective review of our patients was performed longitudinally by using the survival analysis method. The postoperative state of epilepsy in 76 patients who underwent resection surgery was assessed based on Engel's criteria. In addition, Kaplan-Meier survival analysis was used to calculate the probability of seizure freedom. In this patient group, abnormal lesion were detected by MRI in 70 out of 76 cases, and the ictal onset zone was finally identified within temporal lobe in 51 cases. The most favorable outcome, defined as Engel Class Ia, was observed in 26 (37%), 24 (40%), and 18 (41%) cases at 2, 5, and 10 years after surgery, respectively. The Kaplan-Meier survival curve in the overall group estimated the probability of seizure freedom as 75% (95% confidence interval [CI] 70-80%), 67% (62-72%), and 51% (45-57%) at 2, 5, and 10 years follow up, respectively. Half of all seizure recurrences occurred within the first 2 postoperative years. In this study, we showed that long-term favorable outcome of seizure control following resection surgery can be achieved in more than half of the patients.
    Neurologia medico-chirurgica 10/2013; · 0.49 Impact Factor
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    ABSTRACT: Our work and the study of Bilican et al. highlight the need for complementary assays to detect subtle phenotypic differences between control and mutant induced pluripotent stem cell lines.
    Science translational medicine 06/2013; 5(188):188lr2. · 10.76 Impact Factor
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    ABSTRACT: Aim: The aim of this study was to determine the correlation between the growth hormone (GH)-insulin-like growth factor-1 (IGF-1) axis and glucose intolerance in acromegaly during the early postoperative period. Subjects and Methods: The study included 20 patients with acromegaly caused by GH-secreting pituitary adenoma who received transsphenoidal surgery in our hospital. Glucose tolerance was evaluated with oral glucose tolerance tests (OGTTs) performed pre- and early postoperative periods (9 [7-18] days after surgery). Homeostasis model assessment of insulin resistance (HOMA-R) and insulinogenic index (IGI) were calculated, and correlation analyses were performed between these values and the GH- IGF-1 axis. Patients were divided according to postoperative changes of the axis, and glucose tolerance was compared between the groups. Results: In preoperative OGTTs, nine patients had impaired glucose tolerance and two had diabetes mellitus patterns. Postoperatively, significant reduction was observed both in fasting plasma glucose levels (p < 0.01) and in HOMA-R (p < 0.01), whereas IGI showed no significant change. HOMA-R was significantly correlated with serum IGF-1 levels both before (r = 0.83, p < 0.01) and after (r = 0.57, p < 0.01) surgery, although it was not correlated with serum GH levels. Patients who achieved more than 50% postoperative reduction in serum IGF-1 levels showed significant improvement in OGTTs results (p < 0.05). Conclusions: In patients with acromegaly, serum IGF-1 levels, but not GH levels, were significantly correlated with insulin resistance. Early postoperative improvement of glucose tolerance is observed in patients who achieved postoperative reduction in serum IGF-1 levels.
    Journal of endocrinological investigation 05/2013; · 1.65 Impact Factor
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    ABSTRACT: Animals that possess regenerative abilities are widespread in the animal kingdom. Hydra, planarian, zebrafish, newt and axolotl are known prominent species, and the cellular aspects of the stem cell system for regeneration are well elucidated. However, few animals can be used to investigate the molecular basis of neuronal regeneration, in spite of the presence of prominent regenerative animals, as mentioned above. Planarians, for instance, can regenerate a functional brain after amputation in a few days, even from non-brain tissue. Newts can regenerate several tissues and organs (i.e., lens, limbs, jaws, hearts and tails) with recovery of function and physiology after injury or tissue removal. These animals achieve regeneration of missing nervous system utilizing stem cells. However, it is difficult to regenerate nervous system in mammalians, including human beings, although these animals possess neural stem cells. Therefore, regenerative animals provide unique opportunities to investigate the generation and utilization of stem cells to repair lost or injured tissue in non-regenerative animals. On the other hand, the successful derivation of neural cells from human embryonic stem cells (ESCs) and induced pluripotent stem cells (iPSCs) under in vitro conditions provides a new experimental strategy for clinical translation. In other words, although human beings lack regenerative abilities, the new clinical strategy of “regenerative medicine,” including cell-transplantation therapy, has been developed to recover lost neural functions by using stem cells. This research field has become a greatly advancing scientific field worldwide. In this chapter, we focus on the molecular systems of generation of functional dopaminergic (DA) neurons in vivo and/or in vitro in regenerative and non-regenerative animals. The first topic investigates how regenerative animals recruit new DA neurons from stem cells after injury. The second topic explores how to generate DA neurons from mammalian ESCs and iPSCs under in vitro conditions. The third topic evaluates clinical applications for human neural disease, especially Parkinson’s disease.
    04/2013: pages 271-286; , ISBN: 978-953-51-1069-9
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    ABSTRACT: [This corrects the article on p. 11 in vol. 7, PMID: 23423767.].
    Frontiers in Cellular Neuroscience 01/2013; 7:116. · 4.47 Impact Factor
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    ABSTRACT: Induced pluripotent stem cells (iPSCs) provide the potential for autologous transplantation using cells derived from a patient's own cells. However, the immunogenicity of iPSCs or their derivatives has been a matter of controversy, and up to now there has been no direct comparison of autologous and allogeneic transplantation in the brains of humans or nonhuman primates. Here, using nonhuman primates, we found that the autologous transplantation of iPSC-derived neurons elicited only a minimal immune response in the brain. In contrast, the allografts caused an acquired immune response with the activation of microglia (IBA-1(+)/MHC class II(+)) and the infiltration of leukocytes (CD45(+)/CD3(+)). Consequently, a higher number of dopaminergic neurons survived in the autografts. Our results suggest that the autologous transplantation of iPSC-derived neural cells is advantageous for minimizing the immune response in the brain compared with allogeneic grafts.
    Stem cell reports. 01/2013; 1(4):283-292.
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    Kaneyasu Nishimura, Jun Takahashi
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    ABSTRACT: Parkinson's disease (PD) is one of the candidate diseases for cell transplantation therapy, since successful clinical experiments have accumulated using human fetal tissue grafting for PD patients. Although some grafted PD patients have shown drastic improvements, several issues still remain with regard to using human fetal tissue. This review highlights the recent advances in stem cell technology toward clinical applications using human pluripotent stem cells. In particular, pluripotent stem cells, such as embryonic stem cells and induced pluripotent stem cells (iPSCs), are the focus as a source of cell transplantation therapy that can be used instead of human fetal tissues. Additionally, efficient methods for stem cell maintenance and differentiation have been developed and improved toward the clinical transition. These advances in the basic technologies have helped accelerate the realization of regenerative medicine. We also review the current topics regarding disease modeling and drug screening using iPSC technology. Finally, we also describe the future prospects of these stem cell research fields toward clinical application.
    Biological & Pharmaceutical Bulletin 01/2013; 36(2):171-175. · 1.85 Impact Factor
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    ABSTRACT: We herein report three cases of gonadotroph adenoma in men (36-72 years of age) presenting with visual impairment and suprasellar masses measuring approximately 20 to 30 mm in diameter. Endocrinological examinations were normal, except for slightly increased follicle stimulating hormone (FSH) levels in two cases. Based on the tentative diagnosis of non-functioning pituitary adenoma, transsphenoidal surgery was performed, which revealed that the tumors consisted of FSH- and LH-positive cells. As gonadotroph adenoma is very common among patients with clinically silent pituitary adenoma, it should be diagnosed using pathological examinations.
    Internal Medicine 01/2013; 52(11):1199-1202. · 0.97 Impact Factor
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    ABSTRACT: Figure optionsView in workspaceDownload full-size imageDownload as PowerPoint slide
    01/2013; 1(4):283–292.
  • Asuka Morizane, Daisuke Doi, Jun Takahashi
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    ABSTRACT: Pluripotent stem cells are promising potential sources for cell replacement therapy and are useful research tools for exploring disease mechanisms. Neural cells are one of the cell types that have been most efficiently differentiated through several established protocols. This chapter describes the feeder-free floating aggregation culture system for the induction of dopaminergic neurons. This method is simple and highly efficient for the production of dopaminergic neurons. It has several advantages for application in clinical usage in comparison to the other protocols using either feeder cells or Matrigel.
    Methods in molecular biology (Clifton, N.J.) 01/2013; 1018:11-9. · 1.29 Impact Factor
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    ABSTRACT: PURPOSE: Glioblastoma (GBM) is one of the worst cancers in terms of prognosis. Standard therapy consists of resection with concomitant chemoradiotherapy. Resistance to nimustine hydrochloride (ACNU), an alkylating agent, has been linked to methylguanine DNA methyltransferase (MGMT). Daily administration of procarbazine (PCZ) has been reported to decrease MGMT activity. This study investigated the efficacy of ACNU + PCZ compared to ACNU alone for GBM and anaplastic astrocytoma (AA). METHODS: Patients (20-69 years) who had newly diagnosed AA and GBM were randomly assigned to receive radiotherapy with ACNU alone or with ACNU + PCZ. The primary endpoint was overall survival (OS). This was designed as a phase II/III trial with a total sample size of 310 patients and was registered as UMIN-CTR C000000108. RESULTS: After 111 patients from 19 centers in Japan were enrolled, this study was terminated early because temozolomide was newly approved in Japan. The median OS and median progression-free survival (PFS) with ACNU alone (n = 55) or ACNU + PCZ (n = 56) in the intention-to-treat population were 27.4 and 22.4 months (p = 0.75), and 8.6 and 6.9 months, respectively. The median OS and median PFS of the GBM subgroup treated with ACNU alone (n = 40) or ACNU + PCZ (n = 41) were 19.0 and 19.5 months, and 6.2 and 6.3 months, respectively. Grade 3/4 hematologic adverse events occurred in more than 40 % of patients in both arms, and 27 % of patients discontinued treatment because of adverse events. CONCLUSIONS: The addition of PCZ to ACNU was not beneficial, in comparison with ACNU alone, for patients with newly diagnosed AA and GBM.
    Cancer Chemotherapy and Pharmacology 12/2012; · 2.80 Impact Factor
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    ABSTRACT: Although transplanted pluripotent stem cell-derived neurons can contribute to functional recovery in animal models of Parkinson's disease, the risk of tumor formation hinders clinical applications of this approach. Removing undifferentiated cells from the donor population is critical to reduce tumorigenesis. Moreover, immature neural progenitors in transplants can proliferate unpredictably, resulting in neural overgrowth and long-term risks of compressing the surrounding host tissue. Because Notch signaling plays a role in maintaining the multipotency and proliferative capacity of neural progenitors, we used γ-secretase inhibitors (GSIs) to dampen Notch signaling in human-induced pluripotent stem cell-derived neural progenitors before transplantation and examined the effects on the growth of proliferative grafts. We observed a marked reduction in the percentage of dividing cells and increased neuronal maturation in GSI-treated samples in vitro. Next, grafts were transplanted into the striata of nonobese diabetic/severe combined immune deficiency mice. Histological analyses performed 8 weeks after the operation showed that grafts pretreated with GSIs-N-[N-(3,5-difluorophenacetyl)-l-alanyl]-S-phenylglycine t-butyl ester or compound E-were significantly smaller than control samples. Immunohistologic analyses revealed that briefly treating the donor population with GSIs not only reduced the graft volume, but also altered the composition of the graft; control grafts showed neural overgrowth with numerous PAX6(+) and Ki67(+) neural rosettes, whereas GSI-treated samples developed into mature neuronal grafts containing primarily Tubβ3(+) cells. These results suggest that pretreating potentially proliferative progenitors with GSIs may improve the safety of cell replacement therapies using pluripotent stem cells.
    Stem cells and development 09/2012; · 4.15 Impact Factor
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    ABSTRACT: Amyotrophic lateral sclerosis (ALS) is a late-onset, fatal disorder in which the motor neurons degenerate. The discovery of new drugs for treating ALS has been hampered by a lack of access to motor neurons from ALS patients and appropriate disease models. We generate motor neurons from induced pluripotent stem cells (iPSCs) from familial ALS patients, who carry mutations in Tar DNA binding protein-43 (TDP-43). ALS patient-specific iPSC-derived motor neurons formed cytosolic aggregates similar to those seen in postmortem tissue from ALS patients and exhibited shorter neurites as seen in a zebrafish model of ALS. The ALS motor neurons were characterized by increased mutant TDP-43 protein in a detergent-insoluble form bound to a spliceosomal factor SNRPB2. Expression array analyses detected small increases in the expression of genes involved in RNA metabolism and decreases in the expression of genes encoding cytoskeletal proteins. We examined four chemical compounds and found that a histone acetyltransferase inhibitor called anacardic acid rescued the abnormal ALS motor neuron phenotype. These findings suggest that motor neurons generated from ALS patient-derived iPSCs may provide a useful tool for elucidating ALS disease pathogenesis and for screening drug candidates.
    Science translational medicine 08/2012; 4(145):145ra104. · 10.76 Impact Factor
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    ABSTRACT: Induced pluripotent stem (iPS) cells possess the properties of self-renewal and pluripotency, similar to embryonic stem cells. They are a good candidate as a source of suitable cells for cell replacement therapy. In this study, we transplanted human iPS cell-derived neural progenitors into an ischemic mouse brain. Human iPS cells were differentiated into neuronal progenitors by serum-free culture of embryoid body-like aggregates (SFEBs). Focal cerebral ischemia was induced by occluding the middle cerebral artery using the intraluminal filament technique. Donor cells were transplanted into the ischemic lateral striatum 1 week after ischemia induction. Cells survived at the transplantation site, with migration of a proportion of cells along the external capsule and corpus callosum. Cells that were positive for the basal telencephalon marker, Nkx2.1, migrated into the basal part of the telencephalon. The pallial telencephalon marker, Emx1, was detected in cells that had migrated into the pallial part of the telencephalon. SFEBs differentiated into various types of neurons, and a retrograde tracer labeling study showed that differentiated cells integrated into host neural circuitry. Behavioral recovery was significantly enhanced in the transplanted group. Our results suggest that human iPS cell-derived neuronal progenitors survive and migrate in the ischemic brain, and contribute toward functional recovery via neural circuit reconstitution.
    Brain research 03/2012; 1459:52-60. · 2.46 Impact Factor
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    ABSTRACT: Cerebral ischemia causes neuronal death and disruption of neural circuits in the central nervous system. Various neurological disorders caused by cerebral infarction can severely impair quality of life and are potentially fatal. Functional recovery in the chronic stage mainly depends on physical treatment and rehabilitation. We aim to establish cell therapy for cerebral ischemia using embryonic stem (ES) cells, which have self-renewing and pluripotent capacities. We previously reported that the transplanted monkey and mouse ES cell-derived neural progenitors, by stromal cell-derived inducing activity method, could survive and differentiate into various types of neurons and glial cells, and form the neuronal network in basal ganglia. In this report, we induced the differentiation of the neural progenitors from mouse ES cells using the serum-free suspension culture method and confirmed the expression of various basal ganglial neuronal markers and neurotransmitter-related markers both in vitro and in vivo, which was thought to be suitable for replacing damaged striatum after middle cerebral artery occlusion. This is the first report that used selectively induced telencephalic neural progenitors into ischemia model. Furthermore, we purified the progenitors expressing the neural progenitor marker Sox1 by fluorescence-activated cell sorting and Sox1-positive neural progenitors prevented tumor formation in ischemic brain for 2 months. We also analyzed survival and differentiation of transplanted cells and functional recovery from ischemic damage.
    Laboratory Investigation 02/2012; 92(4):522-31. · 3.96 Impact Factor
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    ABSTRACT: For the safe clinical application of embryonic stem cells (ESCs) for neurological diseases, it is critical to evaluate the tumorigenicity and function of human ESC (hESC)-derived neural cells in primates. We have herein, for the first time, compared the growth and function of hESC-derived cells with different stages of neural differentiation implanted in the brains of primate models of Parkinson's disease. We herein show that residual undifferentiated cells expressing ESC markers present in the cell preparation can induce tumor formation in the monkey brain. In contrast, a cell preparation matured by 42-day culture with brain-derived neurotrophic factor/glial cell line-derived neurotrophic factor (BDNF/GDNF) treatment did not form tumors and survived as primarily dopaminergic (DA) neurons. In addition, the monkeys with such grafts showed behavioral improvement for at least 12 months. These results support the idea that hESCs, if appropriately matured, can serve as a source for DA neurons without forming any tumors in a primate brain.
    Stem Cells 02/2012; 30(5):935-45. · 7.70 Impact Factor

Publication Stats

3k Citations
472.58 Total Impact Points

Institutions

  • 1990–2014
    • Kyoto University
      • • Center for iPS Cell Research and Application (CiRA)
      • • Institute for Frontier Medical Sciences
      • • Graduate School of Pharmaceutical Sciences / Faculty of Pharmaceutical Sciences
      • • Department of Neurosurgery
      • • Department of Brain Pathophysiology
      Kioto, Kyōto, Japan
  • 2010
    • Kyoto Medical Center
      Kioto, Kyōto, Japan
  • 2006–2010
    • Tazuke Kofukai Medical Research Institute, Kitano Hospital
      Ōsaka, Ōsaka, Japan
  • 2007
    • Kishiwada City Hospital
      Kisiwada, Ōsaka, Japan
  • 2006–2007
    • Kanazawa University
      • Department of Neurosurgery
      Kanazawa, Ishikawa, Japan
  • 2005
    • University Hospital Medical Information Network
      • Department of Neurosurgery
      Tokyo, Tokyo-to, Japan
  • 2004
    • National Cerebral and Cardiovascular Center
      Ōsaka, Ōsaka, Japan
  • 2000
    • Osaka City University
      • Graduate School of Medicine
      Ōsaka, Ōsaka, Japan