The search for the best source of stem cells continues, with many scientists supporting the field of stem cell research. The most recent discovery in this domain is that made by a team of European scientists who have developed a culture method for establishing “human adult germline stem cells” from testicular biopsies.

For the new study conducted by Thomas Skutella and colleagues at the University of Tubingen, the researchers biopsied the cells from human testicles and grew them in laboratory cultures. They used testicular tissue from 22 men, aged from 17 to 81, to create what they called “germline stem cells.” Researchers found that after a few weeks of growth in laboratory cultures containing factors that supported the development of stem cells, the testes cells took on the characteristics of embryonic stem cells.

According to the study published in Thursday’s issue of the journal Nature, the new type of stem cells could be useful for growing bone, muscle, neural and other kinds of cells that might be used to replace or repair the damaged tissue in male patients with generative diseases. (The benefits of this new method would probably apply only in men.)

“We have developed a culture method for establishing human adult germline stem cells from testicular biopsies,” Skutella and colleagues wrote. “These cells changed their properties, losing characteristics of spermatogonial cells and acquiring characteristics ... similar to those of human embryonic stem cells.”

The discovery allows researchers the opportunity to study diseases like Parkinson or any kind of inherited disease using biopsies taking from people with these conditions. Researchers say the same technique can be used to study many other genetic diseases. The stem cells might be used to create new cells that could replace the diseased ones in patients who suffer from genetic diseases.

Stem cells have the potential to develop into many different cell types in the body, serving as a sort of repair system for the body. They can divide without limit to replace other cells in the body as long as the person or the animal is still alive. Unlike other cells such as muscle cells, blood cells, or nerve cells, the stem cells divide and each new cell may remain a stem cell or become another type of cell with a specialized function.

Another method developed during the last two years uses skin cells taken from patients, reprogramming them into embryonic-like stem-cells. The technique uses genes and viruses, but researchers have tried to improve this method by developing a safer way of obtaining stem cells from common skin cells without using harmful viruses that can cause cancer. They found a new method that uses adenoviruses. The adenovirus doesn’t integrate into the genome, so the cells aren’t altered genetically.

But the technique which uses testicular biopsies is easier and it uses a man’s own cells to heal his body. This means that the method could be used without fear that the body would reject the cells. Another advantage of this method, compared to embryonic stem cells is that it has fewer moral restrictions and problems and the testicular cells are natural.

Both the technique that reprograms ordinary body cells into stem cells and the method using testicular cells avoid embryos, but scientists say this advantage is not a reason strong enough to give up on research on embryonic stem cell research.