Author & Adult Stem Cell Scientist

The February 9 Time Magazine cover reads: "How the Coming Revolution in Stem Cells Could Save your Life – Diabetes, Heart Disease, Parkinson's".  We have been hearing about Stem Cell science for years. What is new in this article? Can you summarize the key point?

The key point of the Time article is the description of a recently developed new way of creating stem cells, by manipulating a few genes of an otherwise normal tissue cell.

How does that work and what is the meaning of this new development?

Each cell of the body contains the very same DNA that was present when every one of us was just an embryo made of embryonic stem cells.  Therefore, the "embryonicness" that is so characteristic of embryonic stem cells, that is their ability to proliferate and become cells of virtually all tissues, is still present in each cell of our body.  However, since this "embryonicness" is no longer needed after birth, that part of the genome is suppressed. 

The main problem with embryonic stem cells is the high risk of forming tumor cells.

A few years ago, Shinya Yamanaka, a Japanese scientist, identified four genes that essentially encode for this "embryonicness".  Therefore it is possible to transform a normal cell of the body into a embryonic-like cell by activating these genes.  So in theory it is possible to work with embryonic-like stem cells without having to damage human embryos.

Is there a reason to be cautious about this new development?

I believe so; yes because this is exactly what a cancer cell is, a rogue cell that has hijacked the "embryonicness" present in the DNA.  The main problem with embryonic stem cells is the high risk of forming tumor cells. The genes responsible for their "embryonicness" are suppressed after birth to prevent the formation of abnormal tissue –essentially cancer- that would soon or later mean death. 

So nature in its wisdom has specifically developed a way to suppress these genes to prevent disease formation after birth.  When these genes are added or activated, against nature's decree, I think we are playing with very dangerous fire.  We are essentially awakening chaos in a cell, we have no idea what this could bring.

Are you saying that this development is irrelevant?

Unlike embryonic stem cells that can become all cells types and therefore create tumors, adult stem cells will only become cells of the tissue in which they find themselves.

Absolutely not.  As the article is pointing out clearly, even if these cells cannot be used for actual treatment, they can allow scientists to further study the biology of stem cells and the formation of disease and that in itself is important.  

The article talks about novel ways of transforming a cell without have to revert to an embryonic-like state.  Can you comment on this?

The article refers to Dr. Melton's work on the transformation of a non-insulin-producing pancreatic cell into an insulin-producing cell.  In other words, the ability to take a cell and to awaken the part of the gene that encodes for a specific function, i.e. making insulin, without having to go through the state "embryonicness".  This work is very interesting, but again it involves the manipulation of genes that can have consequences that are unseen at this point.

Similar results have been seen by simply allowing Adult Stem Cells to get in contact with pancreatic tissue.  Liver stem cells for example can transform into insulin-producing pancreatic cells upon contact with the pancreas.  So there is no need to go though such sophisticated genetic manipulation with unknown consequences, when one's own stem cells (Adult Stem  Cells) can be used very simply. 

So with Adult Stem Cells, we have the regenerative potential of making new tissue without the risk of tumor formation. There is no doubt in my mind that the future of stem cell is with adult stem cells.

But the article suggests that Adult Stem Cells are too limited, that they can only become specific types of tissue. 

This is probably one of the biggest misunderstandings and confusions in the field of stem cell research.  Yes, Adult Stem Cells are limited to becoming cells of the tissue in which they find themselves, but this is precisely why they carry such great promise.  Unlike embryonic stem cells that can become all cells types and therefore create tumors, adult stem cells will only become cells of the tissue in which they find themselves.

It is not that Adult Stem Cells are intrinsically limited, as they do have the ability to become cells of virtually any tissue, but after migrating in a tissue they do become limited to the tissue in which they find themselves.  So with Adult Stem Cells we have the regenerative potential of making new tissue without the risk of tumor formation.  There is no doubt in my mind that the future of stem cell is with adult stem cells.