GENETIC NEWS

Testicle Stem Cells Become Bone, Muscle in German Experiments
Stem cells were isolated from the testicles of adult men and turned into bone, muscle, neural and other kinds of cells, German researchers said.
The advance, reported today in the journal Nature, may provide an alternative way to generate powerful stem cells that might be used to repair or replace damaged tissue in male patients with hard-to-treat diseases. Currently, scientists create stem cells by extracting them from embryos or genetically manipulating adult cells to make them pluripotent, or able to become many other cell types.

The use of testicle cells may also represent a new way to make lines of cells from a male with an inherited disease, for the purpose of studying his condition at the cellular level and testing drugs that might be effective in treating it.

The work by Thomas Skutella, director of the Center for Regenerative Biology and Medicine, in Tuebingen, Germany, produced a ``breathtaking result,'' said George Daley, a researcher at the Harvard Stem Cell Institute and at Children's Hospital Boston. While scientists had known that mouse testes give rise to other cells, he said, it wasn't clear that such cells could be isolated from humans.

``These are the only pluripotent cells present in adult human organisms,'' Skutella said. With this method, he said, ``you could take biopsies from people with Parkinson's or any kind of inherited disease'' and study the cells to learn how they function and respond to drugs.

The technique, if confirmed and improved, may allow researchers to sidestep ethical controversies that have dogged the field since University of Wisconsin scientists isolated stem cells from human embryos a decade ago.

Embryo Research Decried

Critics of embryonic research, including the Catholic Church, U.S. President George W. Bush and German lawmakers, view embryo destruction as immoral. Bush banned federal funding of research that uses newly destroyed embryos. German authorities went further, barring researchers there from creating embryonic stem cells, although they can import those derived in other countries, Skutella said.

Another method, developed two years ago by Japanese researchers, uses genes and viruses to reprogram adult skin cells so they become pluripotent and behave like embryonic stem cells. While this method avoids using embryos, the technique may trigger cancer or other unwanted effects. More recently researchers have begun to refine this method by eliminating viruses linked to cancer.

One advantage of Skutella's method is that if a man's own cells were used to make a therapy, they could be used to treat him without fear that his body would reject the cells. While he was able to coax the testicular stem cells to turn into a number of cell types, he wasn't able to make still other types, including heart cells.

Testicles Donated

Skutella and his colleagues obtained testicular tissue from various sources, including organ donors who had died. Others who supplied tissue were being treated for infertility or had their testicles removed in the course of surgery to change their sex to female or to treat prostate cancer.

The scientists used a complex process to identify and isolate a type of precursor cell that normally helps make sperm. They then concocted a chemical cocktail that allowed them to expand the stem cells.