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Breakthrough Study: Stem Cells Found in Testicles

By L.K. Regan

There's new hope in stem cell research this month, thanks to the efforts of scientists in the UK and Germany, writing this month in the journal Nature, who have found a new source for these versatile cells. In fact, you're carrying around an enormous supply of them right now. That's because, the researchers have discovered, stem cells can be harvested from human testicles. The discovery promises to offer new avenues in stem cell research, and treatment of disease in men.

Stem cells are uniquely versatile cells, capable of developing into virtually any other kind of cell. They are found in large numbers in human embryos, because they are necessary for development of a complete body. Their versatility gives them enormous potential for treating disease, as they can be converted for multiple uses within the body—but acquiring them has involved the use of destroyed embryos. This has raised complex ethical issues surrounding the use of embryos for experimental purposes, and has figured large in the ongoing political conflict over abortion. So, for the last several years scientists have been searching for other, less controversial sources for stem cells. Now, they believe they've found them—in the testicles.

The researchers from the Universities of Tübingen and Cologne in Germany, and King's College, London harvested stem cells from the testicles of 22 men through routine biopsies. These cells had developed for particular use in sperm production within the testicles, but the researchers managed to persuade the cells to regress to an earlier state of development found in very early-phase embryos. Ordinarily, this process would require inserting DNA into the cells to change them into stem cells—but in the testicular cells this was done using the same cell culturing procedure employed to persuade embryonic stem cells to take various forms. This offers the potential for a simpler, more effective way of obtaining stem cells.

The possibility of harvesting stem cells from adult men has enormous potential for personalized medical care. As the study's authors write, "We conclude that the generation of human adult germline stem cells from testicular biopsies may provide simple and non-controversial access to individual cell-based therapy without the ethical and immunological problems associated with human embryonic stem cells." Effectively, one's own cells could be used to heal the body, and repair the effects of disease, or treat progressive diseases such as Parkinson's, Alzheimer's, or cancer. Because of the shared DNA between the patient and the stem cells, the cells should pass through the person's immune system unchallenged, reducing or eliminating the possibility of rejection.

There is one catch, however: the testicular stem cells could only be used to treat men. While the testicular stem cells show a great deal of promise, a complete answer to the ethical and technical complexities surrounding stem cells still awaits.