South Korean Scientists Announce Stem Cell Breakthrough

Read the Full Transcript

• RAY SUAREZ:

  The scientific world was astonished by today's news that South Korean scientists have extracted colonies of patient-specific stem cells from newly created human embryos. The same scientists have derived stem cells before from an embryo, but this time, for the first time, the stem cell lines genetically matched a range of patients with a variety of illnesses.

  The process, known as therapeutic cloning, was also far more efficient than any previous attempt. To obtain those stem cells, scientists took the DNA of skin cells from patients with diseases or illnesses, and then removed the nucleus of a separate egg cell from another donor. The cells were then fused together so that the DNA From the patient's skin cell was implanted in the egg. Those fused cells divided into early stage embryos, which are normally about 100 cells or more.

  The new, cloned embryo then had the same genetic material as those of patients with different diseases. The embryonic stem cells were then removed. The hope is those stem cells could be used one day to repair, regenerate or replace damaged organs and tissues. To walk us through the science and significance of this advance, I'm joined by Dr. David Scadden, the co-director of the Harvard Stem Cell Institute. Dr. Scadden, to begin, I think we should really explain just a little further what a stem cell is.

• DR. DAVID SCADDEN:

  Sure. A stem cell is a cell type that can become many different types of cells, and there are really two major kinds of stem cells. The one that we're speaking of tonight is one that's formed during the first few days following the formation of an embryo, and that cell type can become virtually any tissue type of the body. So it can become a nerve cell, a cell from the blood or a cell from the liver, for example.

  Whereas, an adult stem cell which really refers to all the cells that are later in development, and that would include umbilical cord stem cells and those which would be derived from adults, and those cells are powerful and they're the ones we use in clinical practice today. But they're much more limited because if they are derived from the blood, they can make other kinds of blood cells, but they cannot make the cells that are important in diabetes, for example.

• RAY SUAREZ:

  So, in the case of the South Korean breakthrough, we're talking about embryonic stem cells?

• DR. DAVID SCADDEN:

  That's correct.

• RAY SUAREZ:

  So, what was the South Korean team able to do that really represents a big breakthrough, a departure from what other teams have been able to do so far?

• DR. DAVID SCADDEN:

  Well, for the most part, we've been working with stem cells from the embryos that have been discarded in fertility clinics, and those are cells that are for the most part derived from people who have no diseases. What they've been able to do in Korea is to say if we want to look at a problem that is representative of a disease, we need to go to the setting where those diseases occur, and those would be in adults.

  With again an embryonic cell from such an individual you can imagine that's scientifically very complicated. So what they did was to take the nucleus, the brains or the DNA of the cell, from – say from the skin of an individual who had a disease, put that into an egg, whose nucleus had been removed, and the egg then makes, or in some ways convinces, the nucleus of the skin cell to think that it's an embryo, and it starts to form an early embryo.

  That then allows us to be able to — what they've been able to do is create a group of cells that when grown in a Petri dish could be sustained over a period of time and they represent identical match in DNA to the donor. That's very important because it represents both the contents that led to the disease, and also it represents something that's identical, in terms of it possibly not being rejected by the donor of the cells.

• RAY SUAREZ:

  Now is this something that's every never been done before, or never been done before so reliably and repeatedly? What exactly do we have here?

• DR. DAVID SCADDEN:

  Right, so just over a year ago, this same group demonstrated that they could do it, but they were able to do it once. They got one cell line after having tried it many, many times in over 250 eggs.

  So it seemed as if it was something that, while that was of great import, may or may not have been reproducible, may or may not be something that had any practical significance. Today what they're reporting is that they can do this with only a small number of eggs; they've gone from over two hundred fifty down to an average of seventeen and sometimes as few as five.

  That means that this precious resource of the egg can now be used very efficiently, and they've been able to do it not just by taking the nucleus of a specialized cell, which they had done before, but by taking it from individuals who were older, who had diseases and so they showed that they can could do this fairly routinely or rather repetitively in a way that allows us to be able to think we could do this on a much broader scale, and maybe get a full spectrum of cell types for a number of different diseases for which we currently have very little therapy.

• RAY SUAREZ:

  Well, is this a tribute to their technical skill, their theoretical skill, dogged work ethic, a little of all of it?

• DR. DAVID SCADDEN:

  I think it is probably all of that. Certainly, this is based on a strong background of research that they had done in this area in the past, but it also is the kind of thing that takes a tremendous amount of dedication and attention to detail. And they've been able to do that in a way that no one else has been able to accomplish. One of the issues is, of course, that it's not been able to be done here essentially at all because of the absence of our ability to use federal funding for it.

• RAY SUAREZ:

  So the work they're doing there would be against the law in the United States?

• DR. DAVID SCADDEN:

  No, it's not actually against the law and not against any federal law. There are some states that have restricted embryonic stem cell research, but because most of the drive of new research in this country is really driven by either private enterprise or by the government, with the government being a far greater source of that, that in the absence of either the interest of Biopharma or the willingness of the government to support this, that it really has ground to a halt, and that is very difficult for any individual institution to muster up the resources to do it.

  We're trying to do that at Harvard, and making headway with that. But, as you can imagine, to do this on just an occasional one laboratory here, one laboratory there, that's really not going to be able to compete with an effort that's really been the dedicated response of almost an entire nation.

• RAY SUAREZ:

  And the South Korean research is government funded?

• DR. DAVID SCADDEN:

  It is. And it has become a major emphasis within the Korean biomedical enterprise, and it's frankly rather disturbing to think that this is an area, the use of embryonic stem cells or the work with them that was initially started in the U.S. but now we're clearly trailing in this particular area.

• RAY SUAREZ:

  The South Korean team has now successfully created these stem cell lines. Is the science advanced enough so that the cells can be reliably manipulated and instructed to become one thing or another?

• DR. DAVID SCADDEN:

  Well, we haven't worked with these cell lines in particular to know that. But in general, with embryonic stem cells, it has been possible to get them to become particular cell types. There's still an enormous amount to be learned here.

  You can't just say to a cell become a heart cell and it will do it and the cues that are necessary to make that happen routinely is still something that is being worked out. What we do know is the cells have the capacity, and the hope is we'll be able to get to the point where if we need a uniform population of cells that are the insulin-producing cells of the pancreas, we can achieve that. But that's still something that requires a great deal of work.

• RAY SUAREZ:

  Now that this happened, does this change the terms of the debate in the United States? We're now moving into a new chapter in the stem cell debate here. Can we put up borders around science?

• DR. DAVID SCADDEN:

  Yeah, I think this is – certainly this raises concern among those who have already been very suspect of this kind of research. It doesn't ease the moral concerns that people have who have been opposed to it.

  I think what we do know is we've entered an area where we could start to think about studying rare diseases, diseases for which we have no therapy using this kind of a cell type, and it's an important issue that we can possibly make use of these cell lines; we would like to make new cell lines so that w can do this more efficiently.

  And unfortunately, we now have to actually turn to others to provide this. I think if we can get some success in these lines, it would greatly change the debate.

  At the moment, what we're hoping is that we can just gain enough confidence of supporters of this kind of work, that they realize we want to do this with carefully constructed boundaries in a thoughtful way so that we can take advantage of the opportunities this offers for people suffering from these diseases, and yet not allow for the kind of abuse some people are very concerned about.

• RAY SUAREZ:

  Dr. Scadden, thanks for being with us.

• DR. DAVID SCADDEN:

  Thank you very much.