Stem-cell research represents a patchwork of patchworks. Understanding this can help the research community to manage it effectively

The field of human stem cell research is buffeted by the forces of hope and controversy, and the interplay between them has contributed to a highly varied environment for conducting stem cell research. International and regional policies covering this work are complex and in flux. The resulting situations both between and within jurisdictions can be termed a 'patchwork of patchworks'.

best in science, biology, gene, liverby Monya Baker

A single added gene prompts liver progenitor cells to make insulin and reverse diabetes

With the introduction of a single gene, cells in the liver can take on the function of pancreatic cells and go on to reverse symptoms of diabetes in a mouse model of the disease. Researchers led by Lawrence Chan at Baylor College of Medicine in Houston, Texas, had already shown that they could, in effect, cure diabetes in mice by infecting their livers with a virus containing the gene for neurogenin (Ngn3), a transcription factor that is expressed as cells begin differentiating into insulin-producing beta-cells, the type of cells lost in juvenile diabetes. Although the researchers knew that this process worked, they did not know why, so they began trying to figure out which cells in the liver began producing insulin.

by Monya Baker

Three recent papers and questions for clinical translation

It's not easy to assess the quality of science from press releases, three of which caught my eye this month. All of them described the use of stem cells for neurodegenerative applications. All of them looked interesting, but I wanted to be particularly careful because of their potential for translation to human patients as well as their company connections. I asked Phil Schwartz, a neural stem cell expert at Children's Hospital of Orange County, California, to help me understand the gaps between study and therapy, and then I asked authors from each paper to respond. The papers were published in Biomaterials1, The Journal of Comparative Neurology2 and Cell Transplantation3.

by Bryn Nelson

Some think the US should adopt a UK regulatory structure for embryo research

Officials at the US National Institutes of Health (NIH) will be kept busy for the next four months as they craft new guidelines specifying which embryonic stem (ES) cell research will now qualify for federal funding. But that hasn't stopped the first rumblings of a fight over what the country's regulatory framework might eventually look like.

stem cells, plant, science, biologyby Asher Mullard

New technique allows gene-expression analysis

The shoot apical meristem continues to make leaves, flowers and branches throughout a plant's life, so it must contain stem cells. These reside in a complex three-dimensional structure consisting of perhaps three dozen stem cells surrounded by niche cells and millions of differentiating cells. This makes the stem cells within the meristem hard to isolate. In fact, most researchers pursuing genomic studies of plant stem cells have turned instead to roots. Now, using an Arabidopsis thaliana mutant that produces an unusually high number of accessible shoot apical meristems, G. Venugopala Reddy of the University of California, Riverside and his colleagues have found a way to study shoots and have produced a gene-expression map of the meristem that reveals the molecular signatures of these elusive stem cells.

john dick, science, biologyby Monya Baker

The University of Toronto scientist calls for more controversy

John Dick identified the first cancer stem cell, in leukaemia. The widely used xenotransplantation assay that he developed can confirm the identity of prospective haematopoietic stem cells by demonstrating their ability to re-establish a human blood system in the mouse. He is a professor at the University of Toronto and its affiliated Princess Margaret Hospital and Director of the Program in Cancer Stem Cells at the Ontario Institute for Cancer Research. 

Tell me about the xenotransplantation assay.

Lucky for us that there is enough complementarity between what human stem cells need and what the mouse can provide so you can get human repopulation of the mouse's blood system.

In the blood system, there are a lot of steps that a cell has to go through to read out as a stem cell. You take a source of stem cells, you put it in a syringe and you squirt them into the blood stream. Essentially you are taking advantage of a beautiful property of these cells, which is [their ability] to find their way to the bone marrow.

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