The first announcement of this year’s Nobel season was made this morning. The Nobel Prize for Physiology or Medicine has gone to John Gurdon and Shinya Yamanaka. This is a case where the work being awarded is very well known, even outside of scientific circles. Induced pluripotent stem cells, colloquially known as “adult stem cells,” have been discussed in many forums for their potential for revolutionary medical treatments.
What’s exciting about this work is that this discovery is key to enabling future therapeutic successes of stem cells. One such therapeutic application is one that I have long considered to be a Holy Grail problem: the growth of complex organs for transplants. Currently, there have been some early successes in this area, particularly in growing relatively simple organs such as bladders (first performed in 2006) and tracheae (first clinical use in 2008,) we are quite far away from organs such as livers, hearts, and kidneys. Both of these tissue engineering successes have used a type of stem cell that can be isolated from a patients own bone marrow, rather than the induced pluripotent cells that have won this year’s Nobel. It is expected that Yamanaka’s work will be key to developing more complex organs.
From the Nobel perspective, this work should have been on anyone’s short list of potential winners. Yamanaka shared last year’s Wolf Prize in Medicine with Rudolf Jaenisch of MIT for this discovery and Jaenisch’s subsequent use of the technique to treat a genetic disease in a mammal, thus providing a proof of concept for its therapeutic use. What is interesting is that the Nobel committee did not choose to include Jaenisch in today’s award.
Induced pluripotent stem cells have a long history. Gurdon’s work in replacing the nuclear material of a frog egg cell with the nuclear material from a tadpole was originally performed in 1962. While this success would not appear to deal with stem cells, the learning that a mature, differentiated cell could be reverted to an immature state was key to Yamanaka’s later work. What Yamanaka did was to find the specific gene sequences necessary to revert a mature cell to a stem cell, and then transfecting adult cells in order to force the expression of those sequences.
Inveterate geeks will recall the scene in Star Trek 4 where Dr. McCoy gives a dialysis patient a pill that induces the growth of a new kidney. Induced pluripotent stem cells may bring us closer to those kinds of therapies are available outside of the movie theater.
Coming tomorrow: the Physics Nobel. We’ll see if my earlier predictions are accurate.