What role might human embryonic stem cells play in treating disease?
The most publicized clinical goal of stem cell research is often called “regenerative medicine.” This strategy would involve nudging stem cells in the cell culture dish to evolve, or differentiate, into the specialized cells that make up each of the body’s tissues. If scientists can meet this challenge, then, theoretically: • Beating-heart cells could be transplanted into diseased or damaged heart tissue. • Dopamine-producing brain cells could replenish those destroyed in Parkinson’s patients. Right now, scientists can observe embryonic stem cells in the culture dish differentiate spontaneously into specialized cells. And they’ve learned that certain chemicals, or growth factors, can drive the cells to specialize randomly. But scientists can’t yet control the direction in which the cells specialize. They need to figure out how to control this specialization, so that they can prompt a cell to become, say, a liver cell rather than a heart cell. This requires identifying the many genetic
