New cells could be alternative to embryo research

A cell that can be made to grow into any other tissue in the body has been discovered by an American scientist.

If the finding is confirmed, it could make the cloning of embryos for their cells unnecessary. Instead, the newly discovered cells could be used to grow new organs or tissues to replace failing ones. They would also have potential for treating people with failing kidneys or Alzheimer's disease.

Professor Catherine Verfaillie, a specialist in stem cells at Minnesota University, told colleagues that she has found cells in the bone marrow of human adults which show "multipotence", or the ability to grow into different body tissues. With the right biological stimulus these "multipotent adult progenitor cells" (MAPCs) can turn into muscle, cartilage, bone, liver and even neuron and brain cells. Other adult cells do not have this potential – liver cells, for example, can not become skin cells.

"The work is very exciting," Ihor Lemischka, associate professor in molecular biology at Princeton University, told New Scientist magazine. "They can differentiate into pretty much everything that an embryonic stem cell can differentiate into."

Embryonic stem cells, which come from developing embryos less than 14 days old, had seemed the best hope for growing organs. However the prospect of a less controversial source of stem cells will be welcomed by many scientists.

Professor Verfaillie's group has yet to publish its findings in a peer-reviewed scientific journal, but says that is because it is filing for patents before making the full results public.

One doubt that has been raised is whether the MAPCs actually produce functional cells. "Stem cells may express [chemical] markers characteristic of many cell types," said one researcher, "but simply detecting those doesn't prove that a stem cell really has become, say, a working neuron."