Induced pluripotent stem cells (iPSCs), with both pluripotency and replication competence similar to embryonic stem cells (ESCs), have been developed from mouse fibroblasts in 2006 by Yamanaka et al. iPSCs are unique in employing somatic cells for their production, and can avoid ethical issues existing in ESCs. It is clear that progress in technology to produce iPSCs is one of the most crucial achievements of medicine in this century. Technology with the new pluripotent cells will offer many advantages in the field of regeneration medicine supplying new tissues to the injured organ and/or development of methodology to uncover many genetic diseases. On the other hand, we have to await adequate progress in issues regarding iPSCs, including enhanced efficiency to obtain iPSCs, the technology to produce organs from the cells, avoidance of tumorigenesis and decrease in immunity in response to iPSCs.

According to Wikipedia, translational research is scientific research that facilitates the translation of findings from basic science to practical applications that enhance human health and well-being. In this special issue, the topic of translational research in anesthesiology was featured. Six subtopics including 1) adaptation of induced pluripotent stem (iPS) cells to central nerve injury, 2) signaling of granulocyte macrophage colony stimulating factor and its clinical application: host-defense and organ protection, 3) molecular mechanisms of chronic pain and its therapeutic strategy, 4) endoplasmic reticulum stress and opioid tolerance, 5) relationships of damage-associated molecular patterns and organ injury, and 6) translational research in omics science to clinical anesthesia, are presented and discussed in detail. Anesthesiologists always keep in mind that the goal of translational research is to improve our health through research and that there would be no bright future in anesthesiology without the fruits of translational research.

In 2006, Takahashi et al. established a method for reprogramming somatic cells by introducing definite transcription factors, which enabled the generation of induced pluripotent stem cells (iPSCs) with pluripotency comparable to that of embryonic stem cells. In turn, it has become possible to use these iPSCs for producing various tissues needed for the treatment of neurodegenerative disorders, which have been difficult to obtain from living bodies. This advancement is expected to bring forth rapid progress in the clarification of mechanisms underlying the diseases and discovery of new innovative drugs and lead to rapid progress in regenerative medicine. In recent years, recapitulation and analysis of disease conditions using iPSCs derived from the patients themselves have been reported, and remarkable advances have been made, even for late-onset neurodegenerative disorders. These findings show that the phenotypes of late-onset neurodegenerative disorders can be recapitulated in iPSC-derived neuronal cells, which are reflected the early developmental stages, indicating cellular abnormalities exist from the prenatal period, despite the late onset diseases. In this review, we summarize the state of iPSCs research in the context of neurodegenerative disorders, discuss the possible ways for understanding the mechanisms underlying neurodegenerative disorders and discovering new drugs, and describe some other aspects of regenerative medicine.

Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by synovitis and bone destruction leading to irreversible joint deformity. The development of a novel treatment for RA aiming at joint repair is necessary. Recently, mesenchymal stem cells (MSCs) have been widely studied as a new therapeutic tool for the treatment of RA, due to their multipotency and also their immunosuppressive properties. We show here that MSCs inhibit osteoclast differentiation depending on the constitutive production of osteoprotegerin, a decoy receptor of receptor activator of nuclear factor kappa-B ligand (RANKL). Our results further indicate that MSCs are useful in RA treatment by preventing the progression of bone damage by inhibiting osteoclast differentiation. In addition, MSCs are likely to play important roles in bone metabolism and maintenance of joint formation. In conclusion, MSC is a promising tool for both anti-inflammation and bone repair for RA patients.

A 45-year-old woman with acute myelogenous leukemia developed platelet transfusion refractoriness (PTR) after the engraftment of an allogeneic peripheral blood stem cell transplantation (PBSCT) from her multiparous sister, which was attributed to HLA antibodies that could not be detected in the patient's serum before transplantation. She achieved neutrophil engraftment by day 18 and megakaryocytopoiesis and complete donor chimerism was confirmed in the bone marrow on day 21. IgG-class HLA antibodies were detected in her serum on day 24 after PBSCT; however, on day 15, no HLA antibodies were detected. The specificity of the antibodies that emerged in the patient closely resembled that of the antibodies found in the donor. The donor had probably been immunized during pregnancy by their partner's HLA-antigens expressed by the fetus. Consequently, transplanted donor-derived cells provoked HLA antibodies in the recipient early after PBSCT, and those HLA antibodies induced PTR. The presence of HLA antibodies should be examined at least in pregnant female donors whose recipients developed PTR attributable to HLA antibodies after SCT.

Systemic sclerosis (SSc) is a multisystem connective tissue disease characterized by excessive fibrosis and microvasculopathy, along with poor vascular formation and repair. The maintenance of the postnatal vascular system requires constant remodeling through vasculogenesis, which is mediated by the de novo differentiation of mature endothelial cells from endothelial progenitor cells (EPCs). However, a great deal of controversy about EPCs and their roles in postnatal vascular formation has arisen because of discrepancies in how EPCs are defined. The current consensus is that EPCs are heterogeneous cell population containing an extremely small count of "true EPCs", and pro-angiogenic hematopoietic cells (PHCs) that promotes vascular formation and repair through secretion of pro-angiogenic factors, and differentiation into endothelial cells and mural cells. In 2004, we reported a reduced number and impaired function of circulating CD34(+)CD133(+)CD309(+)CD45(dim)CD14(-) EPCs, which are now regarded as an immature subset of PHCs, in patients with SSc, and proposed a theory that defective vascular repair machinery as one of important mechanisms contributing to SSc vasculopathy. In addition, we showed that in SSc patients, circulating monocytic PHCs were increased and have enhanced angiogenic potency and differentiation potential to fibroblast-like cells. In summary, EPCs are involved in the pathogenesis of SSc by participating in two major pathological features, microvasculopathy and excessive fibrosis. Understanding the roles of EPCs in disease process of SSc may be key to dissecting its pathogenesis and to developing novel therapeutic strategies for this intractable condition.

A high dose of melphalan followed by autologous stem cell transplantation (ASCT) is considered as the standard therapy for multiple myeloma. For induction therapy, 78 patients received conventional regimens (control group) and 32 patients received bortezomib-containing regimens (bortezomib group). We retrospectively compared the yield of harvested CD34+ cells between the two groups. In order to mobilize CD34+ cells, 83% of the control group and 63% of the bortezomib group received a high dose of cyclophosphamide followed by G-CSF, and 12% of the control group received a high dose of etoposide instead of cyclophosphamide. Furthermore, 5% of the control group and 38% of the bortezomib group received G-CSF alone for CD34+ cell mobilization. Overall, the yield of CD34+ cells was higher in the control group than in the bortezomib group (7.4 vs. 5.2×10(6)/kg, P=0.004). Regarding the patients mobilized by a high dose of cyclophosphamide followed by G-CSF, the rate of achieving CD34+ cells >2.0×10(6) cells/kg was similar. Bortezomib did not significantly affect the successful collection of at least CD34+ cells > 2.0×10(6) cells/kg after mobilization with a high dose of cyclophosphamide followed by G-CSF.

Although mammalian neurogenesis is mostly completed by the perinatal period, new neurons are continuously generated throughout adulthood in the restricted regions of the brain. Newly generated neurons are incorporated into the neural networks of both the hippocampal dentate gyrus and the olfactory bulb, and there is growing evidence that adult neurogenesis is important for various brain functions. Continuous neurogenesis is achieved by the coordinated proliferation and differentiation of adult neural stem cells. In this review, we discuss the recent findings concerning the roles of Notch signaling and Hes-family genes in adult neural stem cells. We also discuss the recent findings about the integration mode of new neurons into the existing neural circuits and the potential significance of adult neurogenesis in higher brain functions, such as spatial and olfactory memory.

Induced pluripotent stem (iPS) cells are generated from somatic cells by introducing small sets of transcription factors. iPS cells demonstrate pluripotency and the ability to self-renew. In addition, iPS cells can be generated from donor individuals with particular characteristics. Based on these features, iPS cells are expected to be applicable in drug discovery, the study of disease mechanisms and cell therapy. From a technical point of view, "diversity" is the key word. At present, iPS cells can be derived using various techniques, resulting in diversity in the quality of iPS cells generated. Therefore, optimization of the derivation technology is one of the most important issues. Another "diversity" is in the propensities amongst iPS cell lines derived using similar techniques. Thus, strategies for selecting good quality lines remain to be established. Considering such technical hurdles, establishment of an iPS cell bank consisting of high quality and versatile iPS lines is a promising idea because of the merits of cost and quality control. Now, we are exploring relevant parameters for the quality control of banked cells. The challenges facing clinical application of iPS cells are new but not unprecedented. To realize clinical applications of iPS cells, we need to make these challenges clear and overcome them through partnership not only with industry, governments and universities, but also patients and society at large.

Our research of stem cell transplantation using mouse embryonic stem (ES) cells and induced pluripotent (iPS) cells was carried out from the aspect of trophic factor, cell differentiation, and better survival of grafted cells. Pleiotrophin, an enhanced trophic factor in the dopamine (DA)-depleted striatum, increased the number of DAergic neurons from ES-derived neural stem cells (ES-NSCs), increased cell survival of cultured DAergic neurons, and affected cell survival of grafted DAergic cells in Parkinson model rats. It was shown that DAergic differentiation from ES-NSCs was mediated by hypoxia inducible factor 1-alpha. Our challenges of the transplantation of ES-NSCs and iPS-derived oligodendrocyte progenitor cells (iPS-OPCs) into periventricular leukomalasia (PVL) model rats are also presented. It was found that grafted ES-NSCs survived better in the corpus callosum without immunosuppressant and most of them differentiated into neurons near the grafted site. It was also revealed that only a few of the grafted iPS-OPCs induced by a stepwise culture method with no use of serum could survive in PVL model rats, indicating that trophic factor (s) and improvement of graft techniques will be needed for better survival of grafted iPS-OPCs.