Mice testicles yield 'ethical' stem cells

    Men’s testicles may provide an “ethical” source of embryonic stem cells (ESCs), suggest new experiments in mice.

    A team in Germany has successfully grown mouse ESC-like cells from spermatagonial stem cells which normally turn into sperm. The ESC-like cells can be grown into all tissues of the mouse body, suggesting that if the same could be done in men, it would provide patients with a source of tissue-matched cells for repairing any damaged organs or tissue.

    So far, all existing colonies of human ESCs have been derived from surplus human embryos, leftover from infertility treatments. Because a human embryo is sacrificed in the process, many religious groups oppose such research, especially in the US where President George W Bush has placed heavy restrictions on federal stem cell researchers.

    The discovery that cells which behave like ESCs can now be obtained from adult mice may now open up the possibility of a similar “ethical” source from grown men.

    “We’re in the process of doing this in humans, and we’re optimistic,” says Gerd Hasenfuss of the Georg-August University of Göttingen, Germany, and head of the team which pioneered the breakthrough.

    He told New Scientist that his team is already taking testicle-tissue samples under consent from patients undergoing operations for other conditions, such as cancer.

    “It’s rather painful, and is usually done under general anaesthetic, but it’s routinely done to gain sperm for IVF, for example, so it’s a well-known procedure,” says Hasenfuss. He notes that the cells would not be obtainable from a sperm or semen sample. “It has to be a biopsy.” Leap to humans

    Although forbidden by law in Germany from obtaining ESCs from embryos, or even working on ESCs derived from the same source in other countries, Hasenfuss backs research on both sources – from adults and embryos.

    To circumvent the ethical objections, his team has attempted for years to derive ESCs from adult tissues, and the testicular source is only success so far. ESCs were obtained from embryonic mice in 2004 by Mito Kanatsu-Shinohara and his colleagues at Kyoto University, Japan, but Hasenfuss says he is the first to get them from adult mice.

    Other researchers welcomed the findings. “On the basis of what I see, I couldn’t discount what they say they’ve achieved,” says Paul de Sousa at the University of Edinburgh, UK. “The real news is the capacity to sustain these cells in culture and retain their ability to turn into all tissue,” he says.

    “But it may be a leap of faith to apply it in humans,” de Sousa cautions. “I would be wary that things in humans would be as simple.”