Neural Development by Transplanted Human Embryonal Carcinoma Stem Cells Expressing Green Fluorescent Protein

Article Commentary: Stem Cell Research in Cell Transplantation: An Analysis of Geopolitical Influence by Publications

One of the fastest growing fields in researching treatments for neurodegenerative and other disorders is the use of stem cells. These cells are naturally occurring and can be obtained from three different stages of an organism's life: embryonic, fetal, and adult. In the US, political doctrine has restricted use of federal funds for stem cells, enhancing research towards an adult source. In order to determine how this legislation may be represented by the stem cell field, a retrospective analysis of stem cell articles published in the journal Cell Transplantation over a 2-year period was performed. Cell Transplantation is considered a translational journal from preclinical to clinical, so it was of interest to determine the publication outcome of stem cell articles 6 years after the US regulations. The distribution of the source of stem cells was found to be biased towards the adult stage, but relatively similar over the embryonic and fetal stages. The fetal stem cell reports were primarily neural in origin, whereas the adult stem cell ones were predominantly mesenchymal and used mainly in neural studies. The majority of stem cell studies published in Cell Transplantation were found to fall under the umbrella of neuroscience research. American scientists published the most articles using stem cells with a bias towards adult stem cells, supporting the effect of the legislation, whereas Europe was the leading continent with a bias towards embryonic and fetal stem cells, where research is “controlled” but not restricted. Japan was also a major player in the use of stem cells. Allogeneic transplants (where donor and recipient are the same species) were the most common transplants recorded, although the transplantation of human-derived stem cells into rodents was the most common specific transplantation performed. This demonstrates that the use of stem cells is an increasingly important field (with a doubling of papers between 2005 and 2006), which is likely to develop into a major therapeutic area over the next few decades and that funding restrictions can affect the type of research being performed.

Stem Cells in Cell Transplantation

This commentary documents the increased number of stem cell-related research reports recently published in the cell transplantation field in the journal Cell Transplantation. The journal covers a wide range of issues in cell-based therapy and regenerative medicine and is attracting clinical and preclinical articles from around the world. It thereby complements and extends the basic coverage of stem cell physiology reported in Stem Cells and Development. Sections in Cell Transplantation cover neuroscience, diabetes, hepatocytes, bone, muscle, cartilage, skin, vessels, and other tissues, as well as tissue engineering that employs novel methods with stem cells. Clearly, the continued use of biomedical engineering will depend heavily on stem cells, and these two journals are well positioned to provide comprehensive coverage of these developments.

Growth of Teratomas Derived from Human Pluripotent Stem Cells Is Influenced by the Graft Site

Pluripotent stem cells transplanted into immune-deficient mice form complex teratomas. Although such tumors are generally haphazard in their organization, they do contain some structures that resemble tissues normally seen in the embryo. As a consequence, the teratoma model is useful for exploring the developmental potential of stem cells and studying certain aspects of tissue development. To further our understanding of this process, we examined whether the anatomical location into which human pluripotent stem cells were grafted influenced their growth in situ. Here we report that cells grafted into the liver rapidly produced large tumors containing predominantly immature cells. In contrast, subcutaneous implants were significantly slower growing and eventually formed tumors composed of differentiated tissues. The alternative growth patterns recorded between these two graft sites indicates how environmental cues affect stem cell behavior. This approach may lead to the identification of new ways to control stem cell growth and differentiation.