Stem Cell Research and Regenerative Medicine in 2014: First Year of Regenerative Medicine in Japan

Such a positive trend at least stems from recent groundbreaking achievements in stem cell biology and regenerative medicine, including the establishment of induced pluripotent stem (iPS) cell technologies by Yamanaka and colleagues [1,2]. Notably, in 2014, Dr. Masayo Takahashi at the Laboratory for the Retinal Regeneration Project, Center for Developmental Biology, RIKEN, Japan, is going to start the first clinical trial using iPS cell-derived cell products. The Takahshi Group is aiming to transplant autologous iPS cell-derived retinal pigment epithelium sheets in patients suffering from wet-type age-related macular degeneration (AMD) [3]. Following this application for AMD, several clinical trials examining iPS cell-based cell therapy are currently being prepared for patients with Parkinson's disease, spinal cord injury, thrombocytopenia, myocardial infarction, and other diseases in Japan [4]. There is also increasing interest in modeling human diseases using iPS cell technologies, which could contribute to the future drug screening and preemptive medicine [5,6]. Considering these possibilities, iPS cell technologies are expected to open a new era, providing enormous opportunities in the field of biomedical research. However, needless to say, safety-related concerns for iPS cell-based cell therapy should be resolved before the clinical application of iPS cells in the field of regenerative medicine [7,8].

However, I wish to emphasize that iPS cell technology is not the sole advantage of Japanese stem cell science. As already summarized in the Theme Issue “Japan: Its Tradition and Hot Topics in Biological Sciences” in the Philosophical Transaction of the Royal Society B in 2008, stem cell biology has been described as a strong and exciting research field in Japan, together with single-molecule imaging and neuroscience [9]. Almost 150 years ago, when the Meiji period began, the Japanese government invited prominent European scientists to build the new so-called Imperial Universities to facilitate the nation's science and technology. Many of the prominent scientists who were invited included professors of developmental biology and embryology, which has resulted in the advantage of a long history in the training of talented human resources in this field in Japan [9]. On the other hand, regretfully, serious confusion and controversies appeared in 2014 regarding the new method of obtaining pluripotent cells through the exposure of somatic cells to sublethal stresses [10]. This new method and proposed concept for the stress-induced acquisition of pluripotency needs to be tested by third parties. Obviously, Japanese stem cell researchers need to overcome this unfavorable situation with solid experimental data and transparency in this memorable First Year of Regenerative Medicine in Japan.

In the present Japan Issue of this Journal, to celebrate the First Year of Regenerative Medicine in Japan, I wish to introduce some excellent stem cell research efforts in Japan, particularly in the following fields from the following laboratories:

1. Pluripotent stem cells and differentiation (Kosodo and colleagues [11]; Ohneda and colleagues [12]; Egusa et al. [13]; Okuda and colleagues [14]; Furue and colleagues [15]).

I hope that you will enjoy this Special Issue of Stem Cells and Development and that this issue will lead to a wider appreciation of our nation's contribution to stem cell research and regenerative medicine.