Details of a Researcher - Nakamura, Masaya

Papers - Nakamura, Masaya

Division display 1 - 20 of about 305 ／ All the affair displays >>

Generation and characterization of a novel shoulder contracture mouse model

Oki Satoshi, Shirasawa Hideyuki, Yoda Masaki, Matsumura Noboru, Tohmonda Takahide, Yuasa Kazuki, Nakamura Masaya, Matsumoto Morio, Horiuchi Keisuke

Journal of Orthopaedic Research 33 ( 11 ) 1732 - 1738 2015.11

ISSN 0736-0266

Frozen shoulder is a relatively common disorder that leads to severe pain and stiffness in the shoulder joint. Although this disorder is self-limiting in nature, the symptoms often persist for years, resulting in severe disability. Recent studies using human specimens and animal models have shown distinct changes in the gene expression patterns in frozen shoulder tissue, indicating that novel therapeutic intervention could be achieved by controlling the genes that are potentially involved in the development of frozen shoulder. To achieve this goal, it is imperative to develop a reliable animal joint contracture model in which gene expression can be manipulated by gene targeting and transgenic technologies. Here, we describe a novel shoulder contracture mouse model. We found that this model mimics the clinical presentation of human frozen shoulder and recapitulates the changes in the gene expression pattern and the histology of frozen shoulder and joint contracture in humans and other larger animal models. The model is highly reproducible, without any major complications. Therefore, the present model may serve as a useful tool for investigating frozen shoulder etiology and for identifying its potential target genes.

Access to Document (DOI)

A Novel Percutaneous Guide Wire (S-Wire) for Percutaneous Pedicle Screw Insertion

Ishii Ken, Kaneko Yasuhito, Funao Haruki, Ishihara Shinichi, Shinohara Akira, Nakanishi Kazuo, Hikata Tomohiro, Fujita Nobuyuki, Iwanami Akio, Hosogane Naobumi, Watanabe Kota, Nagura Takeo, Nakamura Masaya, Toyama Yoshiaki, Matsumoto Morio

Surgical Innovation 22 ( 5 ) 469 - 473 2015.10

ISSN 1553-3506

Purpose. Minimally invasive spine stabilization (MISt) procedures, including MIS-transforaminal lumbar interbody fusion (MIS-TLIF), rely on precise placement of percutaneous pedicle screws (PPS). Serious intraoperative complications associated with PPS placement include great vessel and bowel injuries due to the guide-wire's anterior migration and penetration through the anterior aspect of the vertebral body. To address this issue, we developed a novel percutaneous guide wire (S-wire) and compared the biomechanical characteristics of S-wire and conventional wire in cadaveric spines, and to evaluate the S-wire's efficacy and safety in a clinical trial. Methods. The S-wire is hollow, with braided wires extending at one tip. We compared the push-out and penetration forces of the S-wire and conventional wire in fresh cadaveric lumbar spines, from L1 to L5. Results. Push-out forces caused the braided tip of the S-wire to bend or spread, and thus to resist anterior migration. The mean push-out forces for the S-wire and conventional wire were 15.5 ± 1.9 and 5.7 ± 0.8 N, respectively (P <.0001); the mean penetration forces were 69.1 ± 4.2 and 37.1± 4.8 N, respectively (P <.0005). There was no wire breakage or anterior-wall penetration in a clinical trial of 922 S-wires; interestingly, the pull-out force increased in 780 (84.6%) S-wires after placement. Conclusions. The mean push-out and penetration forces for the S-wire were approximately 3 and 2 times greater than those of conventional wire, respectively. The S-wire effectively prevented guide-wire anterior migration and penetration of the anterior vertebral-body wall. The S-wire device should effectively improve the safety of MISt procedures, including MIS-TLIF and percutaneous kyphoplasty in selected patient with osteoporosis.

Access to Document (DOI)

Histological and electrophysiological analysis of the corticospinal pathway to forelimb motoneurons in common marmosets

Kondo Takahiro, Yoshihara Yamato, Yoshino-Saito Kimika, Sekiguchi Tomofumi, Kosugi Akito, Miyazaki Yuta, Nishimura Yukio, Okano Hirotaka J., Nakamura Masaya, Okano Hideyuki, Isa Tadashi, Ushiba Junichi

Neuroscience Research 98 35 - 44 2015.09

ISSN 0168-0102

Using histological and electrophysiological methods, we identified the neuroanatomical properties of the common marmoset corticospinal tract (CST), which underlies hand/arm motor control. Biotinylated dextran amine (BDA) was injected into the primary motor cortex to anterogradely label CST axons in the cervical segments, revealing that most CST axons descend in the contralateral dorsolateral funiculus (DLF; 85.0%), and some in the ipsilateral DLF (10.7%). Terminal buttons were mainly found in the contralateral lamina VII of the gray matter, but projection to lamina IX, where forelimb motoneurons are located, was rare. Bilateral projections were more abundant than found in the rat CST, resembling the CST organization of other primates. Intracellular recordings were made from 57 forelimb motoneurons on the contralateral side to stimulation, which revealed no monosynaptic excitatory postsynaptic potentials (EPSPs), but di- or polysynaptic EPSPs and inhibitory synaptic potentials were commonly found. Local field potentials showed monosynaptic excitation mainly in laminae VII, where abundant BDA-labeled CST terminals were observed. These results suggest that direct corticomotoneuronal projection is absent in common marmosets but di- or oligosynaptic effects would be mediated by spinal interneurons.

Access to Document (DOI)

BDNF Induced by Treadmill Training Contributes to the Suppression of Spasticity and Allodynia After Spinal Cord Injury via Upregulation of KCC2

Tashiro Syoichi, Shinozaki Munehisa, Mukaino Masahiko, Renault-Mihara François, Toyama Yoshiaki, Liu Meigen, Nakamura Masaya, Okano Hideyuki

Neurorehabilitation and Neural Repair 29 ( 7 ) 677 - 689 2015.08

ISSN 1545-9683

Background. Spasticity and allodynia are major sequelae that affect the quality of life and daily activities of spinal cord injury (SCI) patients. Although rehabilitation ameliorates spasticity and allodynia, the molecular mechanisms involved in these processes remain elusive. Objective. To investigate the molecular mechanisms by which rehabilitation ameliorates spasticity and allodynia after SCI in rats. Methods. The expression levels of brain-derived neurotrophic factor (BDNF) and potassium-chloride cotransporter-2 (KCC2), as well as the localization of KCC2, were examined in the lumbar enlargements of untrained and treadmill-trained thoracic SCI model rats. Spasticity and allodynia were determined via behavioral and electrophysiological analyses. The effects of BDNF on spasticity, allodynia, and KCC2 activation were determined by inhibition of BDNF signaling via intrathecal administration of TrkB-IgG. The effects of SCI and training on the expression levels of functional phospholipase C-γ in the lumbar enlargement were also examined. Results. Treadmill training after SCI upregulated endogenous BDNF expression and posttranslational modification of KCC2 in the lumbar enlargement significantly. There were also significant correlations between increased KCC2 expression and ameliorated spasticity and allodynia. Administration of TrkB-IgG abrogated the training-induced upregulation of KCC2 and beneficial effects on spasticity and allodynia. The expression level of functional phospholipase C-γ was reduced significantly after SCI, which may have contributed to the change in the function of BDNF, whereby it did not trigger short-term downregulation or induce long-term upregulation of KCC2 expression secondary to training. Conclusions. BDNF-mediated restoration of KCC2 expression underlies the suppression of spasticity and allodynia caused by rehabilitation.

Access to Document (DOI)

Migration and differentiation of transplanted enteric neural crest-derived cells in murine model of Hirschsprung’s disease

Nishikawa Ryuhei, Hotta Ryo, Shimojima Naoki, Shibata Shinsuke, Nagoshi Narihito, Nakamura Masaya, Matsuzaki Yumi, Okano Hirotaka J., Kuroda Tatsuo, Okano Hideyuki, Morikawa Yasuhide

Cytotechnology 67 ( 4 ) 661 - 670 2015.08

ISSN 0920-9069

Stem cell therapy offers the potential of rebuilding the enteric nervous system (ENS) in the aganglionic bowel of patients with Hirschsprung’s disease. P0-Cre/Floxed-EGFP mice in which neural crest-derived cells express EGFP were used to obtain ENS stem/progenitor cells. ENS stem/progenitor cells were transplanted into the bowel of Ret−/− mouse, an animal model of Hirschsprung’s disease. Immunohistochemical analysis was performed to determine whether grafted cells gave rise to neurons in the recipient bowel. EGFP expressing neural crest-derived cells accounted for 7.01 ± 2.52 % of total cells of gastrointestinal tract. ENS stem/progenitor cells were isolated using flow cytometry and expanded as neurosphere-like bodies (NLBs) in a serum-free culture condition. Some cells in NLBs expressed neural crest markers, p75 and Sox10 and neural stem/progenitor cells markers, Nestin and Musashi1. Multipotency of isolated ENS stem/progenitor cells was determined as they differentiated into neurons, glial cells, and myofibloblasts in culture. When co-cultured with explants of hindgut of Ret−/− mice, ENS stem/progenitor cells migrated into the aganglionic bowel and gave rise to neurons. ENS stem/progenitor cells used in this study appear to be clinically relevant donor cells in cell therapy to treat Hirschsprung’s disease capable of colonizing the affected bowel and giving rise to neurons.

Access to Document (DOI)

Effects of femoral bone tunnel characteristics on graft-bending angle in double-bundle anterior cruciate ligament reconstruction

Niki Yasuo, Nagai Katsuya, Harato Kengo, Suda Yasunori, Nakamura Masaya, Matsumoto Morio

Knee Surgery, Sports Traumatology, Arthroscopy 2015.08

ISSN 0942-2056

Purpose: Bone tunnel creation techniques influence the 3-dimensional (3D) position of bone tunnels and graft-bending angle in anterior cruciate ligament (ACL) reconstruction. This study assessed graft-bending angle and 3D characteristics of femoral bone tunnels and compared them between outside-in (OI) and transportal (TP) techniques. Methods: Participants comprised 64 patients who underwent anatomic double-bundle ACL reconstruction, allocated to OI and TP groups (n = 32 each). The graft orientation plane exhibiting the largest graft-bending angle at the femoral tunnel aperture with the knee in extension was reconstructed from CT data using 3D imaging software. In this plane, graft-bending angle was compared between the OI and TP techniques. Results: Although positionings of the intra-articular apertures of the femoral and tibial bone tunnels were similar, several spatial parameters of bone tunnels differed between techniques. Graft-bending angles of both anteromedial and posterolateral bundles were significantly more acute with the OI technique than with the TP technique. On coronal-plane CT, angle of the bone tunnel axis relative to the distal condylar axis correlated negatively with graft-bending angle, while in the axial plane, angle of the bone tunnel axis relative to the posterior condylar axis correlated positively with graft-bending angle. Lysholm score, pivot shift test, and anteroposterior laxity at >2.5-year follow-up demonstrated no significant differences between techniques. Discussion: Different bone tunnel directions in OI and TP techniques substantially affected graft-bending angle, despite similar positionings of the intra-articular apertures. Graft-bending angle with the OI technique was acute, but risk of posterior blowout of the lateral femoral condyle was decreased. Surgeons should create the femoral tunnel while considering an obtuse graft-bending angle without increasing the risk of posterior blowout. Level of evidence: III.

Access to Document (DOI)

Comparison of surgical treatments for triple extensor tendon ruptures in rheumatoid hands

Suzuki Taku, Iwamoto Takuji, Ikegami Hiroyasu, Sakuma Y., Ikari Katsunori, Matsumura Noboru, Ochi Kensuke, Sato Kazuki, Nakamura Masaya, Matsumoto Morio, Momohara Shigeki

Modern Rheumatology 2015.08

ISSN 1439-7595

Objective. This retrospective study was designed to evaluate the outcomes of four different surgical reconstructions for extensor tendon ruptures in ulnar three fingers in 48 patients with rheumatoid arthritis. Methods. The following four techniques were performed; palmaris longus tendon grafting (PL group; n = 9), extensor indicis proprius (EIP) tendon transfers (EIP group; n = 8), end-to-side transfers with tension-reduced early mobilization (End-to-side group; n = 16), and a combination of end-to-side and EIP transfers (Combination group; n = 15). Loss of extension was evaluated to determine the mean postoperative range of motion of the metacarpophalangeal (MP) joint and clinical outcomes were categorized using modified Geldmacher criteria. Results. Combination group demonstrated the best mean MP joint extension (− 3°), followed by End-to-side group (− 12°), EIP group (− 16°), and PL group (− 21°). Combination group yielded the best clinical outcomes with all cases showing good results. Conclusions. The combination of end-to-side and EIP transfer was an effective surgical reconstruction procedure for triple fingers extension loss.

Access to Document (DOI)

IRE1α/XBP1-mediated branch of the unfolded protein response regulates osteoclastogenesis

Tohmonda Takahide, Yoda Masaki, Iwawaki Takao, Matsumoto Morio, Nakamura Masaya, Mikoshiba Katsuhiko, Toyama Yoshiaki, Horiuchi Keisuke

Journal of Clinical Investigation 125 ( 8 ) 3269 - 3279 2015.08

ISSN 0021-9738

The unfolded protein response (UPR) is a cellular adaptive mechanism that is activated in response to the accumulation of unfolded proteins in the endoplasmic reticulum. The inositol-requiring protein-1α/X-box-binding protein-mediated (IRE1α/ XBP1-mediated) branch of the UPR is highly conserved and has also been shown to regulate various cell-fate decisions. Herein, we have demonstrated a crucial role for the IREα/XBP1-mediated arm of the UPR in osteoclast differentiation. Using murine models, we found that the conditional abrogation of IRE1α in bone marrow cells increases bone mass as the result of defective osteoclastic bone resorption. In osteoclast precursors, IRE1α was transiently activated during osteoclastogenesis, and suppression of the IRE1α/XBP1 pathway in these cells substantially inhibited the formation of multinucleated osteoclasts in vitro. We determined that XBP1 directly binds the promoter and induces transcription of the gene encoding the master regulator of osteoclastogenesis nuclear factor of activated T cells cytoplasmic 1 (NFATc1). Moreover, activation of IRE1α was partially dependent on Ca2+ oscillation mediated by inositol 1,4,5-trisphosphate receptors 2 and 3 (ITPR2 and ITPR3) in the endoplasmic reticulum, as pharmacological inhibition or deletion of these receptors markedly decreased Xbp1 mRNA processing. The present study thus reveals an intracellular pathway that integrates the UPR and osteoclast differentiation through activation of the IRE1α/XBP1 pathway.

Access to Document (DOI)

Control of the survival and growth of human glioblastoma grafted into the spinal cord of mice by taking advantage of immunorejection

Itakura Go, Kobayashi Yoshiomi, Nishimura Soraya, Iwai Hiroki, Takano Morito, Iwanami Akio, Toyama Yoshiaki, Okano Hideyuki, Nakamura Masaya

Cell Transplantation 24 ( 7 ) 1299 - 1311 2015.07

ISSN 0963-6897

Recent studies have demonstrated that transplantation of induced pluripotent stem cell-derived neurospheres can promote functional recovery after spinal cord injury in rodents, as well as in nonhuman primates. However, the potential tumorigenicity of the transplanted cells remains a matter of apprehension prior to clinical applications. As a first step to overcome this concern, this study established a glioblastoma multiforme xenograft model mouse. The feasibility of controlling immune suppression to ablate the grafted cells was then investigated. The human glioblastoma multiforme cell line U251 MG was transplanted into the intact spinal cords of immunodeficient NOD/SCID mice or into those of immunocompetent C57BL/6J H-2kb mice treated with or without immunosuppressants [FK506 plus anticluster of differentiation (CD) 4 antibody (Ab), or FK506 alone]. In vivo bioluminescent imaging was used to evaluate the chronological survival of the transplanted cells. The graft survival rate was 100% (n = 9/9) in NOD/SCID mice, 0% (n = 6/6) in C57BL/6J mice without immunosuppressant treatment, and 100% (n = 37/37) in C57BL6/J mice with immunosuppressant treatment. After confirming the growth of the grafted cells in the C57/BL6J mice treated with immunosuppressants, immune suppression was discontinued. The grafted cells were subsequently rejected within 3 days in C57BL/6J mice treated with FK506 alone, as opposed to 26 days in C57BL/6J mice treated with FK506 plus anti-CD4 Ab. Histological evaluation confirmed the ablation of the grafted cells. Although this work describes a xenograft setting, the results suggest that this immunomodulatory strategy could provide a safety lock against tumor formation stemming from transplanted cells.

Access to Document (DOI)

Hyperglycemia promotes Schwann cell de-differentiation and de-myelination via sorbitol accumulation and Igf1 protein down-regulation

Hao Wu, Tashiro Syoichi, Hasegawa Tomoka, Sato Yuiko, Kobayashi Tami, Tando Toshimi, Katsuyama Eri, Fujie Atsuhiro, Watanabe Ryuichi, Morita Mayu, Miyamoto Kana, Morioka Hideo, Nakamura Masaya, Matsumoto Morio, Amizuka Norio, Toyama Yoshiaki, Miyamoto Takeshi

Journal of Biological Chemistry 290 ( 28 ) 17106 - 17115 2015.07

ISSN 0021-9258

Diabetes mellitus (DM) is frequently accompanied by complications, such as peripheral nerve neuropathy. Schwann cells play a pivotal role in regulating peripheral nerve function and conduction velocity; however, changes in Schwann cell differentiation status in DM are not fully understood. Here, we report that Schwann cells de-differentiate into immature cells under hyperglycemic conditions as a result of sorbitol accumulation and decreased Igf1 expression in those cells. We found that dedifferentiated Schwann cells could be re-differentiated in vitro into mature cells by treatment with an aldose reductase inhibitor, to reduce sorbitol levels, or with vitaminD<inf>3</inf>, to elevate Igf1 expression. In vivo DM models exhibited significantly reduced nerve function and conduction, Schwann cell de-differentiation, peripheral nerve de-myelination,andall conditionsweresignificantly rescued by aldose reductase inhibitor or vitamin D<inf>3</inf> administration. These findings reveal mechanisms underlying pathological changes in Schwann cells seen in DM and suggest ways to treat neurological conditions associated with this condition.

Access to Document (DOI)

Allogeneic neural stem/progenitor cells derived from embryonic stem cells promote functional recovery after transplantation into injured spinal cord of nonhuman primates

Iwai Hiroki, Shimada Hiroko, Nishimura Soraya, Kobayashi Yoshiomi, Itakura Go, Hori Keiko, Hikishima Keigo, Ebise Hayao, Negishi Naoko, Shibata Shinsuke, Habu Sonoko, Toyama Yoshiaki, Nakamura Masaya, Okano Hideyuki

Stem Cells Translational Medicine 4 ( 7 ) 708 - 719 2015.07

ISSN 2157-6564

Previous studies have demonstrated that neural stem/progenitor cells (NS/PCs) promote functional recovery in rodent animal models of spinal cord injury (SCI). Because distinct differences exist in the neuroanatomy and immunological responses between rodents and primates, it is critical to determine the effectiveness and safety of allografted embryonic stem cell (ESC)-derived NS/PCs (ESC-NS/PCs) in a nonhuman primate SCI model. In the present study, common marmoset ESC-NS/PCs were grafted into the lesion epicenter 14 days after contusive SCI in adult marmosets (transplantation group). In the control group, phosphate-buffered saline was injected instead of cells. In the presence of a low-dose of tacrolimus, several grafted cells survived without tumorigenicity and differentiated into neurons, astrocytes, or oligodendrocytes. Significant differences were found in the transverse areas of luxol fast blue-positive myelin sheaths, neurofilament-positive axons, corticospinal tract fibers, and platelet endothelial cell adhesion molecule-1-positive vessels at the lesion epicenter between the transplantation and control groups. Immunoelectron microscopic examination demonstrated that the grafted ESC-NS/PC-derived oligodendrocytes contributed to the remyelination of demyelinated axons. In addition, some grafted neurons formed synaptic connections with host cells, and some transplanted neurons were myelinated by host cells. Eventually, motor functional recovery significantly improved in the transplantation group compared with the control group. In addition, a mixedlymphocyte reaction assay indicated that ESC-NS/PCs modulated the allogeneic immune rejection. Taken together, our results indicate that allogeneic transplantation of ESC-NS/PCs from a nonhuman primate promoted functional recovery after SCI without tumorigenicity.

Access to Document (DOI)

Synergistic antiproliferative effect of imatinib and adriamycin in platelet-derived growth factor receptor-expressing osteosarcoma cells

Yamaguchi Sayaka I., Ueki Arisa, Sugihara Eiji, Onishi Nobuyuki, Yaguchi Tomonori, Kawakami Yutaka, Horiuchi Keisuke, Morioka Hideo, Matsumoto Morio, Nakamura Masaya, Muto Akihiro, Toyama Yoshiaki, Saya Hideyuki, Shimizu Takatsune

Cancer Science 106 ( 7 ) 875 - 882 2015.07

ISSN 1347-9032

Osteosarcoma (OS) is the most frequent primary solid malignant tumor of bone. Its prognosis remains poor in the substantial proportion of patients who do not respond to chemotherapy and novel therapeutic options are therefore needed. We previously established a mouse model that mimics the aggressive behavior of human OS. Enzyme-linked immunosorbent assay-based screening of such mouse tumor lysates identified platelet-derived growth factor-BB (PDGF-BB) as an abundant soluble factor, the gene for which was expressed dominantly in surrounding non-malignant cells of the tumor, whereas that for the cognate receptor (PDGF receptor β) was highly expressed in OS cells. Platelet-derived growth factor-BB induced activation of both MEK-ERK and phosphatidylinositol 3-kinase-protein kinase B signaling pathways and promoted survival in OS cells deprived of serum, and these effects were blocked by the PDGF receptor inhibitor imatinib. However, these actions of PDGF-BB and imatinib were mostly masked in the presence of serum. Whereas imatinib alone did not manifest an antitumor effect in mice harboring OS tumors, combined treatment with imatinib and adriamycin exerted a synergistic antiproliferative effect on OS cells in vivo. These results suggest that treatment of OS with imatinib is effective only when cell survival is dependent on PDGF signaling or when imatinib is combined with another therapeutic intervention that renders the tumor cells susceptible to imatinib action, such as by inducing cellular stress.

Access to Document (DOI)

Long-term safety issues of iPSC-based cell therapy in a spinal cord injury model

Nori Satoshi, Okada Yohei, Nishimura Soraya, Sasaki Takashi, Itakura Go, Kobayashi Yoshiomi, Renault-Mihara Francois, Shimizu Atsushi, Koya Ikuko, Yoshida Rei, Kudoh Jun, Koike Masato, Uchiyama Yasuo, Ikeda Eiji, Toyama Yoshiaki, Nakamura Masaya, Okano Hideyuki

Stem Cell Reports 4 ( 3 ) 360 - 373 2015.03

ISSN 2213-6711

Previously, we described the safety and therapeutic potential of neurospheres (NSs) derived from a human induced pluripotent stem cell (iPSC) clone, 201B7, in a spinal cord injury (SCI) mouse model. However, several safety issues concerning iPSC-based cell therapy remain unresolved. Here, we investigated another iPSC clone, 253G1, that we established by transducing OCT4, SOX2, and KLF4 into adult human dermal fibroblasts collected from the same donor who provided the 201B7 clone. The grafted 253G1-NSs survived, differentiated into three neural lineages, and promoted functional recovery accompanied by stimulated synapse formation 47 days after transplantation. However, long-term observation (for up to 103 days) revealed deteriorated motor function accompanied by tumor formation. The tumors consisted of Nestin⁺ undifferentiated neural cells and exhibited activation of the OCT4 transgene. Transcriptome analysis revealed that a heightened mesenchymal transition may have contributed to the progression of tumors derived from grafted cells.

Access to Document (DOI)

Breast carcinoma metastasis to meningioma in the thoracic spine

Okada Eijiro, Nakamura Masaya, Koshida Yoshitomo, Mukai Kiyoshi, Toyama Yoshiaki, Matsumoto Morio

Journal of Spinal Cord Medicine 38 ( 2 ) 231 - 235 2015.03

ISSN 1079-0268

Context: Systemic metastasis to a primary tumor of the central nervous system is uncommon. Breast carcinomas metastasizing to a possibly preexisting meningioma in the spine are reported very rarely. Study design: Case report. Findings: A 69-year-old female was referred to us with progressive gait disturbance. She had undergone a total mastectomy for carcinoma of the right breast 11 years previously. A magnetic resonance imaging of the thoracic spine showed an intra- and extradural spinal cord tumor. The patient underwent resection of the tumor via laminectomy from T2 to T4. After the operation, the patient's neurological status improved significantly, and she was able to walk without assistance. Histological examination showed the tumor to be a fibrous-type meningioma within a metastatic breast cancer tumor. The patient underwent 40 Gy radiation treatment for local control of the tumor. However, the tumor recurred locally 7 months after the surgery. The patient died of carcinomatous pleurisy 13 months after the surgery. Conclusion: This case illustrates that a primary meningioma in the thoracic spine can be a recipient of breast cancer metastasis, which may alter the treatment strategy.

Access to Document (DOI)

Controlling immune rejection is a fail-safe system against potential tumorigenicity after human iPSC-derived neural stem cell transplantation

Itakura Go, Kobayashi Yoshiomi, Nishimura Soraya, Iwai Hiroki, Takano Morito, Iwanami Akio, Toyama Yoshiaki, Okano Hideyuki, Nakamura Masaya

PLoS ONE 10 ( 2 ) 2015.02

Our previous work reported functional recovery after transplantation of mouse and human induced pluripotent stem cell-derived neural stem/progenitor cells (hiPSC-NS/PCs) into rodent models of spinal cord injury (SCI). Although hiPSC-NS/PCs proved useful for the treatment of SCI, the tumorigenicity of the transplanted cells must be resolved before they can be used in clinical applications. The current study sought to determine the feasibility of ablation of the tumors formed after hiPSC-NS/PC transplantation through immunoregulation. Tumorigenic hiPSC-NS/PCs were transplanted into the intact spinal cords of immunocompetent BALB/cA mice with or without immunosuppressant treatment. In vivo bioluminescence imaging was used to evaluate the chronological survival and growth of the transplanted cells. The graft survival rate was 0% in the group without immunosuppressants versus 100% in the group with immunosuppressants. Most of the mice that received immunosuppressants exhibited hindlimb paralysis owing to tumor growth at 3 months after iPSC-NS/PC transplantation. Histological analysis showed that the tumors shared certain characteristics with low-grade gliomas rather than with teratomas. After confirming the progression of the tumors in immunosuppressed mice, the immunosuppressant agents were discontinued, resulting in the complete rejection of iPSC-NS/PC-derived masses within 42 days after drug cessation. In accordance with the tumor rejection, hind-limb motor function was recovered in all of the mice. Moreover, infiltration of microglia and lymphocytes was observed during the course of tumor rejection, along with apoptosis of iPSC-NS/PC-generated cells. Thus, immune rejection can be used as a fail-safe system against potential tumorigenicity after transplantation of iPSC-NS/PCs to treat SCI.

Access to Document (DOI)

Effects of Reduction Osteotomy on Gap Balancing During Total Knee Arthroplasty for Severe Varus Deformity

Niki Yasuo, Harato Kengo, Nagai Katsuya, Suda Yasunori, Nakamura Masaya, Matsumoto Morio

Journal of Arthroplasty 2015.01

ISSN 0883-5403

This study aimed to assess the effects of down-sizing and lateralizing of the tibial component (reduction osteotomy) on gap balancing in TKA, and the clinical feasibility of an uncemented modular trabecular metal tibial tray in this technique. Reduction osteotomy was performed for 39 knees of 36 patients with knee OA with a mean tibiofemoral angle of 21° varus. In 20 knees, appropriate gap balance was achieved by release of the deep medial collateral ligament alone. Flexion gap imbalance could be reduced by approximately 1.7° and 2.8° for 4-mm osteotomy and 8-mm osteotomy, respectively. Within the first postoperative year, clinically-stable tibial component subsidence was observed in 9 knees, but it was not progressive, and the clinical results were excellent at a mean follow-up of 3.3years.

Access to Document (DOI)

Neural stem/progenitor cell-laden microfibers promote transplant survival in a mouse transected spinal cord injury model

Sugai Keiko, Nishimura Soraya, Kato-Negishi Midori, Onoe Hiroaki, Iwanaga Shintaroh, Toyama Yoshiaki, Matsumoto Morio, Takeuchi Shoji, Okano Hideyuki, Nakamura Masaya

Journal of Neuroscience Research 2015

ISSN 0360-4012

Previous studies have demonstrated that transplantation of neural stem/progenitor cells (NS/PCs) into the lesioned spinal cord can promote functional recovery following incomplete spinal cord injury (SCI) in animal models. However, this strategy is insufficient following complete SCI because of the gap at the lesion epicenter. To obtain functional recovery in a mouse model of complete SCI, this study uses a novel collagen-based microfiber as a scaffold for engrafted NS/PCs. We hypothesized that the NS/PC-microfiber combination would facilitate lesion closure as well as transplant survival in the transected spinal cord. NS/PCs were seeded inside the novel microfibers, where they maintained their capacity to differentiate and proliferate. After transplantation, the stumps of the transected spinal cord were successfully bridged by the NS/PC-laden microfibers. Moreover, the transplanted cells migrated into the host spinal cord and differentiated into three neural lineages (astrocytes, neurons, and oligodendrocytes). However, the NS/PC-laden scaffold could not achieve a neural connection between the rostral end of the injury and the intact caudal area of the spinal cord, nor could it achieve recovery of motor function. To obtain optimal functional recovery, a microfiber design with a modified composition may be useful. Furthermore, combinatorial therapy with rehabilitation and/or medications should also be considered for practical success of biomaterial/cell transplantation-based approaches to regenerative medicine.

Access to Document (DOI)

Reply to letter to the editor by Toda

Nakamura Masaya, Ushida Takahiro, Toyama Yoshiaki

Journal of Orthopaedic Science 19 ( 6 ) 1057 2014.11

ISSN 0949-2658

Access to Document (DOI)

Regeneration of the damaged central nervous system through reprogramming technology

Matsui Takeshi, Akamatsu Wado, Nakamura Masaya, Okano Hideyuki

Experimental Neurology 260 12 - 18 2014.10

ISSN 0014-4886

Neural stem cell (NSC) transplantation provides a new approach for the repair of damage to the central nervous system (CNS), including that resulting from cerebral infarction and spinal cord injury (SCI). In the past, there were no reputable means of converting non-neural somatic cells into neural cells. This status was overturned by the establishment of induced pluripotent stem (iPS) cells, which have pluripotency akin to that of embryonic stem (ES) cells and can differentiate into most cells of the three germ layers. If differentiated somatic cells could be reprogrammed into iPS cells, and if these iPS cells could be induced to differentiate once again, it would be theoretically possible to obtain a large number of neural cells. However, this is not yet feasible due to the limitations of existing stem cell technology. Induction of neural cells from iPS cells is currently hindered by two distinct problems: 1) the preparation of specific types of targeted neural cells requires extensive cell culture, and 2) tumors are likely to form due to the presence of residual undifferentiated cells following transplantation of the induced cells. By contrast, direct induction methods permit the generation of target cells from somatic cells without the transitional iPS cell stage. This review outlines the present-day status of research surrounding the direct induction of NSCs from somatic cells, as well as the perspectives for the future clinical application of this technique for cell replacement therapy following CNS injury.

Access to Document (DOI)

Focal transplantation of human iPSC-derived glial-rich neural progenitors improves lifespan of ALS mice

Kondo Takayuki, Funayama Misato, Tsukita Kayoko, Hotta Akitsu, Yasuda Akimasa, Nori Satoshi, Kaneko Shinjiro, Nakamura Masaya, Takahashi Ryosuke, Okano Hideyuki, Yamanaka Shinya, Inoue Haruhisa

Stem Cell Reports 3 ( 2 ) 242 - 249 2014.08

ISSN 2213-6711

Transplantation of glial-rich neural progenitors has been demonstrated to attenuate motor neuron degeneration and disease progression in rodent models of mutant superoxide dismutase 1 (SOD1)-mediated amyotrophic lateral sclerosis (ALS). However, translation of these results into a clinical setting requires a renewable human cell source. Here, we derived glial-rich neural progenitors from human iPSCs and transplanted them into the lumbar spinal cord of ALS mouse models. The transplanted cells differentiated into astrocytes, and the treated mouse group showed prolonged lifespan. Our data suggest a potential therapeutic mechanism via activation of AKT signal. The results demonstrated the efficacy of cell therapy for ALS by the use of human iPSCs as cell source. © 2014 The Authors.

Access to Document (DOI)

　 Previous page - Next page 　