快猫短视频

GETTING hold of adult stem cells from patients to treat their diseases might be easier than anyone thought. A team at the University of Iowa claims to have found adult stem cells in the skin that are capable of giving rise to every tissue in the body.

While some scientists are urging caution over the potential of adult stem cells (see Think twice), the hope remains that some of them may be as versatile as embryonic stem cells (ESCs) when it comes to making different tissues. Earlier this year, 快猫短视频 revealed that a team at the University of Minnesota had found stem cells in adult humans that seemed just as plastic as ESCs (26 January, p 4). But obtaining these cells from bone marrow is a painful procedure.

The latest study, in mice, has identified a subset of stem cells in the epidermal layer of the skin that also seem to have broad plasticity. It鈥檚 a distinct population that can be isolated by sorting cells based on their size and the proteins on their surface.

When researcher Jackie Bickenbach injected these stem cells into early mouse embryos, descendants of the cells could be found in most of their tissues. But mice from embryos injected with a different population of cells from the same skin layer had no descendants of the cells in their bodies.

Bickenbach didn鈥檛 expect the cells to be so versatile. 鈥淚 have to tell you, I was pretty surprised,鈥� she says. 鈥淲e now have evidence that they have been living in mice for over a year.鈥� Her team is trying to find out if there are similar cells in human skin.

Ihor Lemishcka of Princeton University points out that better controls are needed in experiments like this to prove that the apparent plasticity isn鈥檛 due to abnormal cell fusion (see Think twice). But despite these concerns, Neil Theise of New York University says he is confident that good evidence of broad plasticity and therapeutic potential for adult stem cells will continue to emerge. 鈥淭his is just the beginning,鈥� he says.

The University of Minnesota researchers have already gone on to show that their bone marrow stem cells can repair the damage caused by strokes. A team led by Walter Low triggered strokes by tying off a blood vessel in the brains of rats. The resulting brain damage made the animals lose control of their limbs.

A week later, the team injected the bone marrow stem cells near the injury area. Not only did the cells home in on the regions that needed repair, but they also began to express markers typical of functional brain cells. Most strikingly, the rats鈥� ability to move their limbs was largely restored, says Low. He hopes this study will be the first step towards moving the technology into clinical trials.