Kiyoshi Okada

Methylcobalamin increases Erk1/2 and Akt activities through the methylation cycle and promotes nerve regeneration in a rat sciatic nerve injury model

Methylcobalamin is a vitamin B12 analog and is necessary for the maintenance of the nervous system. Although some previous studies have referred to the effects of methylcobalamin on neurons, the precise mechanism of this effect remains obscure. Here we show that methylcobalamin at concentrations above 100 nM promotes neurite outgrowth and neuronal survival and that these effects are mediated by the methylation cycle, a metabolic pathway involving methylation reactions. We also demonstrate that methylcobalamin increases Erk1/2 and Akt activities through the methylation cycle. In a rat sciatic nerve injury model, continuous administration of high doses of methylcobalamin improves nerve regeneration and functional recovery. Therefore, methylcobalamin may provide the basis for better treatments of nervous disorders through effective systemic or local delivery of high doses of methylcobalamin to target organs.

Interleukin-1 beta promotes sensory nerve regeneration after sciatic nerve injury.

Nerve injury brings about axonal disconnection, and thus axonal extension is one of the important steps for nerve regeneration. Expression of the pro-inflammatory cytokine interleukin-1 beta (IL-1beta) is increased at the early stage of nervous system injury, and previously IL-1beta has been reported to promote neurite outgrowth by inhibiting RhoA activity in vitro. However, the effect of IL-1beta on axonal extension in vivo has not been obvious. Now we examine whether IL-1beta takes advantages on sciatic nerve regeneration. Sciatic nerves of rats are transected and sutured, and IL-1beta or PBS is locally administered for 2 weeks. Although IL-1beta does not influence on motor functional recovery, it promotes sensory functional recovery, estimated by toe pinch test, and increases the number and the area of neurofilament-positive axons at 12 weeks compared with PBS. Moreover IL-1beta, which promotes Schwann cell proliferation and thus may inhibit myelination, does not impair remyelination, estimated by myelin basic protein. These findings suggest that IL-1beta may contribute to sensory nerve regeneration following sciatic nerve injury by promoting axonal extension.

Akt/mammalian target of rapamycin signaling pathway regulates neurite outgrowth in cerebellar granule neurons stimulated by methylcobalamin.

Methylcobalamin (MeCbl), a vitamin B12 analog, promotes neurite outgrowth by activating Akt in neurons. However, Akt is involved in many cellular functions, and the downstream signal of Akt that promotes neurite outgrowth in neurons in the presence of MeCbl remains obscure. Mammalian target of rapamycin (mTOR) is a serine/threonine protein kinase that regulates multiple cellular functions including neurite outgrowth. mTOR is regarded as important for the regeneration of injured nerves. In this study, we examined the relationship between MeCbl and mTOR activity and found that MeCbl increases mTOR activity via the activation of Akt and promotes neurite outgrowth in cerebellar granule neurons via the activation of mTOR.

Methylcobalamin promotes the differentiation of Schwann cells and remyelination in lysophosphatidylcholine-induced demyelination of the rat sciatic nerve

Schwann cells (SCs) are constituents of the peripheral nervous system. The differentiation of SCs in injured peripheral nerves is critical for regeneration after injury. Methylcobalamin (MeCbl) is a vitamin B12 analog that is necessary for the maintenance of the peripheral nervous system. In this study, we estimated the effect of MeCbl on SCs. We showed that MeCbl downregulated the activity of Erk1/2 and promoted the expression of the myelin basic protein in SCs. In a dorsal root ganglion neuron–SC coculture system, myelination was promoted by MeCbl. In a focal demyelination rat model, MeCbl promoted remyelination and motor and sensory functional regeneration. MeCbl promoted the in vitro differentiation of SCs and in vivo myelination in a rat demyelination model and may be a novel therapy for several types of nervous disorders.

Consideration of and expectations for the Pharmaceuticals, Medical Devices and Other Therapeutic Products Act in Japan *

The Japanese regulatory framework for pharmaceuticals and medical devices has recently been reexamined and the revised Pharmaceutical Affairs Law, which has been renamed the Pharmaceuticals, Medical Devices and Other Therapeutic Products Act, was developed in 2013 and implemented in November 2014. In the revised Act, regenerative medical products are newly categorized and independent from conventional pharmaceuticals and medical devices. This enables these products to be reviewed more appropriately and allows for conditional/time-limited marketing authorization. Following the implementation of the new Act, the Good, Gene Cell and Tissue Manufacturing Practice was established to address the different requirements and concepts for appropriate research and development of regenerative medical products. Based on these changes to the regulatory framework for regenerative medical products in Japan, this article aims to examine how this framework could be utilized as an appropriate system to develop innovative regenerative medicine.

A New National Framework for Clinical Trials and Evaluation of Innovative Medical Care Technologies Using Living Cell Transplantation in Japan

Following the global initiative to develop medical innovative technologies such as living cell transplantation, the Japanese promotion plan, “Five-year Clinical Trial Vitalization Plan 2012” was launched in 2012. Subsequently, “Clinical Trials Core Hospitals” or medical care institutions that performed research and development of innovative technologies were identified, which were regularly evaluated by the “Evaluation System for Investigational Medical Care.” In addition, the regulatory guidelines for pharmaceuticals and medical devices have been reexamined and the revised Pharmaceutical Affairs Law (PAL), which was renamed as the Pharmaceuticals, Medical Devices and Other Therapeutic Products Act (PMD Act), and the Act on the safety of regenerative medicine were developed in 2013 and is scheduled for implementation in November 2014. Based on these changes in the national framework for innovative medical care in Japan, this article aims to explain and evaluate the possibility for this framework to be utilized as the universal case model for stem cell and living cell transplantation.

Electrospun nanofiber sheets incorporating methylcobalamin promote nerve regeneration and functional recovery in a rat sciatic nerve crush injury model

Peripheral nerve injury is one of common traumas. Although injured peripheral nerves have the capacity to regenerate, axon regeneration proceeds slowly and functional outcomes are often poor. Pharmacological enhancement of regeneration can play an important role in increasing functional recovery. In this study, we developed a novel electrospun nanofiber sheet incorporating methylcobalamin (MeCbl), one of the active forms of vitamin B12 homologues, to deliver it enough locally to the peripheral nerve injury site. We evaluated whether local administration of MeCbl at the nerve injury site was effective in promoting nerve regeneration. Electrospun nanofiber sheets gradually released MeCbl for at least 8weeks when tested in vitro. There was no adverse effect of nanofiber sheets on function in vivo of the peripheral nervous system. Local implantation of nanofiber sheets incorporating MeCbl contributed to the recovery of the motor and sensory function, the recovery of nerve conduction velocity, and the promotion of myelination after sciatic nerve injury, without affecting plasma concentration of MeCbl. STATEMENT OF SIGNIFICANCE Methylcobalamin (MeCbl) is a vitamin B12 analog and we previously reported its effectiveness in axonal outgrowth of neurons and differentiation of Schwann cells both in vitro and in vivo. Here we estimated the effect of local administered MeCbl with an electrospun nanofiber sheet on peripheral nerve injury. Local administration of MeCbl promoted functional recovery in a rat sciatic nerve crush injury model. These sheets are useful for nerve injury in continuity differently from artificial nerve conduits, which are useful only for nerve defects. We believe that the findings of this study are relevant to the scope of your journal and will be of interest to its readership.

Radiofrequency ablation for treatment for osteoid osteoma of the scapula using a new three-dimensional fluoroscopic navigation system.

Osteoid osteoma is a relatively common benign skeletal tumor. The traditional standard treatment has been surgical resection of the nidus. Recently, computed tomography (CT)-guided radiofrequency ablation (RFA) has gained favor as a more precise alternative due to potentially less bone destruction. However, CT-guided RFA is limited in treatment for osteoid osteoma involving complex anatomic structures such as cervical spine, pelvis, or scapula because of difficulty in approach and proximity to neurovascular structures. To solve this problem, we investigated RFA using a new real-time three-dimensional fluoroscopic navigation system. We report its technical procedure and use in a rare case of osteoid osteoma of the scapula.

Insurance systems and reimbursement concerning research and development of regenerative medicine in Japan

In Japan, the Act on the Safety of Regenerative Medicine and the Pharmaceuticals, Medical Devices and Other Therapeutic Products Act were enacted in November 2014, creating a new framework for clinical research and products related to regenerative medicine. Together with these regulatory frameworks, new insurance procedures were created for handling regenerative medicine in Japan. For developing regenerative medicine in Japan, understanding medical insurance greatly influences funding and venture success, particularly in the stages between clinical research and market launch. The study aimed to identify the issues and examples surrounding Japans present medical insurance system, especially for regenerative medicine. We believe that building stronger insurance systems for regenerative medicine is essential for internationally aligning and harmonizing the progress of regenerative medicine.

Improvement of Hydrophilicity of Interconnected Porous Hydroxyapatite by Dielectric Barrier Discharge Plasma Treatment

Dielectric barrier discharge plasma treatment has been found to significantly improve hydrophilicity of the surfaces of interconnected porous calcium hydroxyapatite (IP-CHA), particularly that of wall surfaces of the internal pores. IP-CHA has been clinically used as a material for bone substitutes in bone tissue regeneration. Higher hydrophilicity of IP-CHA obtained in this method is expected to further increase the osteoconductivity of IP-CHA.