The technique, described online in a study in Nature Methods this week1, does not involve embryonic stem cells. These come with serious drawbacks when transplanted, such as the risk of developing tumours. Instead, the method uses ordinary cells present in urine, and transforms them into neural progenitor cells — the precursors of brain cells.
Researchers routinely reprogram cultured skin and blood cells2 into induced pluripotent stem (iPS) cells, which can go on to form any cell in the body. But urine is a much more accessible source.