Testes stem cell can change into other body tissues, Stanford/UCSF s...( STANFORD Calif. Scientists at the S...),Health

STANFORD, Calif. Scientists at the Stanford University School of Medicine and at UC-San Francisco have succeeded in isolating stem cells from human testes. The cells bear a striking resemblance to embryonic stem cells they can differentiate into each of the three main types of tissues of the body but the researchers caution against viewing them as one and the same.

According to the study, the testes stem cells have different patterns of gene expression and regulation and they do not proliferate and differentiate as aggressively as human embryonic stem cells.

The findings, published in the January issue of the journal Stem Cells, are in contrast to those reported in a recent Nature paper, which concluded that the cells were, in fact, as pluripotent as embryonic stem cells. Pluripotent cells can become any cell in the body and form tumors called teratomas when transplanted into mice.

"It's time to reinterpret the data," said Renee Reijo-Pera, PhD, professor of obstetrics & gynecology at Stanford, "and to accept that we're beginning to discover many different types of stem cells. Although they are all related to each other, they also all have unique therapeutic applications in which they surpass other family members."

Reijo-Pera, who is the director of Stanford's Center for Human Embryonic Stem Cell Research and Education, collaborated with male infertility specialist Paul Turek, MD, a professor of urology at UCSF and the director of The Turek Clinic in San Francisco, to conduct the research. Reijo-Pera and Turek are co-senior authors of the study.

The stem cells from the testes seem to hover in a gray area between true pluripotency and the more limited, tissue-specific multipotency exhibited by many types of adult stem cells. They termed the cells "multipotent germline stem cells." Germ cells are those cells in the body that differentiate to make sperm and eggs.

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