The Nobel Prize for Medicine and Physiology was awarded last week jointly to John Gurdon of the UK and Shinya Yamanaka of Japan. Their pioneering work in the field of "stem cells" has revolutionized science and can potentially make a huge impact in the field of medicine.
What exactly are "stem cells"?
As you know, cells are the basic structural and functional unit of all living organisms. In the beginning when life begins (embryo), all cells look the same -- in other words, they are known as undifferentiated cells. These cells develop later into heart cells, liver cells, skin cells, muscle cells, brain cells and more. These undifferentiated cells that later grow into specialized, functional cells are known as stem cells.
Gurdon and Yamanaka
John Gurdon’s work that has won the 2012 Nobel Prize for Medicine was done in 1958 and published in 1962. He figured out that a cell, even from the intestine of a frog, contains all the genetic material required to make a new frog. So what did he do?
He took the genetic material from the intestinal cell and inserted into a frog egg. This “cloned” the frog, resulting in a tadpole. This was revolutionary thinking because at that time scientists believed that once a cell had become “specialized” – in this case, an intestine cell, it could not change its type. However, Gurdon showed that it could. Even a specialized cell, under the right conditions, could make different cells – even a whole new tadpole.
Shinya Yamanaka, 40 years after Gurdon, tried something different and equally revolutionary. He worked on skin cells, adding four genes to them. What happened? These already specialized skin cells turned into “stem” cells -- cells that could grow into any type of tissue. This meant that adult cells from any part of the body could be “trained” to become any other type of specialized cell.
That was huge, with big implications. Why? Such “trained” cells could be used to regrow heart tissue, or other damaged tissues – even nerve tissues. Stem cell therapies are used today in bone marrow transplants to help patients with leukemia. In the future, they could be used for other forms of cancer, Parkinsons and other diseases.
What the Nobel Prize-winning work has shown is that even after the adult cells have developed, there are ways to make the stem cells and reprogram them to grow into other types of cells.