By NICHOLAS WADE
from The New York Times

In a surprising advance that sidesteps the ethical debates surrounding stem cell biology, researchers have come much closer to a major goal of regenerative medicine, the conversion of a patient’s cells into specialized tissues that might replace those lost to disease.

The advance is an easy-to-use technique for reprogramming a skin cell of a mouse back to the embryonic state. Embryonic cells can be induced in the laboratory to develop into many of the body’s major tissues.

If the technique can be adapted to human cells, it would let scientists use a patient’s skin cell to generate new heart, liver or kidney cells that might be transplantable and would not be rejected by the patient’s immune system.

Previously, the only way scientists knew they were likely to get such cells is by nuclear transfer, the insertion of an adult cell’s nucleus into an egg whose own nucleus has been removed. The egg somehow reprograms the nucleus back to embryonic state.

The new technique, developed by Shinya Yamanaka of Kyoto University, depends on inserting just four genes into a skin cell. These accomplish the same reprogramming task as the egg, or at least one very similar.

The technique is much easier to apply than nuclear transfer, does not involve the expensive and controversial use of human eggs, and should avoid all or almost all of the ethical criticism directed at the use of embryonic stem cells.

“From the point of view of moving biomedicine and regenerative medicine faster, this is about as big a deal as you could imagine,” said Irving Weissman, a leading stem cell biologist at Stanford University.

David Scadden, a stem cell biologist at the Harvard Medical School, said the finding that cells could be reprogrammed with simple biochemical techniques “is truly extraordinary and frankly something most assumed would take a decade to work out.”

read more at The New York Times