Stem Cell Research

STEM CELL RESEARCH -- (House of Representatives - July 29, 2005)

The SPEAKER pro tempore (Mr. Price of Georgia). Under the Speaker's announced policy of January 4, 2005, the gentleman from Maryland (Mr. Bartlett) is recognized for 60 minutes as the designee of the majority leader.

Mr. BARTLETT of Maryland. Mr. Speaker, I was in my office last evening about 11 p.m., as was all the rest of the House of Representatives, waiting for a resolution of some of the concerns on the transportation bill so that we could vote on it, when we were looking at the ``Drudge Report'' on our screen and we saw there a headline that I could hardly believe, that Senator Frist had reversed his position on embryonic stem cells and was now advocating the passage of the Senate version of H.R. 810.

I thought it would be appropriate today, with stem cells, embryonic stem cells being so much in the news, if we could spend a few minutes looking at what stem cells are and what this is all about, what was Senator Frist talking about and what is the issue here.

I have here on the easel a chart that shows the development, not all of the stages, but it shows the development of the human embryo. It starts with the zygote. The zygote is the fertilized egg. It now has chromosomes, genes from the sperm and genes from the egg, having what we call the diploid number of chromosomes. And that develops through several stages, we will see a little later in another chart, but it goes through the blastacyst stage here and then it goes down to the gastrula stage. And by the time you get to the gastrula stage, the embryo that began as a single cell here just a few days before has now developed into a large number of cells.

What is shown here is the embryo and the part of the wall of the uterus to which it is attached. By this stage in its development, the embryo has already now developed four very specific stem cells that will go on to produce a variety of tissues and organs in the body, all of the tissues and the organs in the body, and we see those down here at the bottom.

Some of them develop into ectoderm. This is the external layer. The ectoderm becomes primarily two things in the developing baby and in the adult. It becomes the skin and the nervous system and some of the pigment cells. Most of what we are in terms of mass is all developed from the middle layer, or the mesoderm, and from that develops all of your skeletal muscle, all of your skeleton, all of your bones, all of your heart muscle, the red blood cells, the smooth muscle in your intestines and stomach and so forth.

Then a third stem cell here ultimately develops into the entoderm. And here we see that this is the lining of the lung, the thyroid gland, and pancreatic cells, nowhere near the mass that is produced by the mesoderm, but very important tissues nevertheless.

Then there are some very unique cells. They are different in the male and the female. They are the germ cells. In the male they produce the sperm and in the female they produce the egg. Some of these stem cells persist even into the adult. In the bone marrow of every adult are stem cells which will produce erythrocytes, your red blood cells, which produce some of your white blood cells. The polymorphonuclear leukocytes will produce those cells that help in clotting, the thrombocytes.

And there are stem cells in other adult tissues. And there has been a lot of research for more than three decades now on using these stem cells to see if we cannot cure or help patients with a number of different diseases. And there have been a number of good applications of adult stem cells. They have produced betterment in a number of individuals, in some cases what looks like actual cures.

But these adult stem cells are limited in their capability because they are already what we call differentiated. They have already split, and a number of the genes have been turned off, and they now are destined to produce only a certain kinds of cells. What the researcher tries to do at times is to take these adult stem cells and put them in an environment that convinces them that they are not really an adult stem cell, but that they have gone now back to a more primordial state, that they are back to an embryonic stem cell.

Here in the blastula we see embryonic stem cells. Of course, the ultimate embryonic stem cell is the zygote: one cell, which will divide again and again and again, and then differentiate, and then finally produce all of the cells of the body. But here in the blastula stage we have the cells already differentiated into two different categories: those cells which are going to produce the embryo, and they are shown here in this inner cell mass; and then those cells which will produce the dissidua. And the dissidua is the cells around this which will become amnion and corion parts of the placenta. In the stage just before this are the cells that can produce the full embryo.

I would like now to look at our next chart here because this shows the development of the embryo, and it has all of the stages there. It starts with the zygote. Here we have the fertilized egg, or the zygote. Of course, this all begins with an ovary. This is only half of the reproductive system of the female. An ovary which every month routinely during the childbearing years will produce an ovum. Here it shows the follicle rupturing and the ovum coming out. Here is the oocyte. And then here are the sperm, and the sperm of course make their way all up through the uterus and the fallopian tube, clear up here to the end of the fallopian tube.

And by the way, they actually sometimes get out into the abdominal cavity. Sometimes this egg is not picked up by this little funnel-shaped end, and you see part of the funnel here, called the infundibulum. Sometimes that cell does not get out there, and it does not get picked up by the fallopian tube and carried down with the beating of a number of cilia and it goes out into the body cavity. And the sperm may actually get out there too, and it can be fertilized there. We call that an ectopic pregnancy. And of course the baby cannot develop there and it is going to die, and it is going to cause a lot of problems for the mother. So this ectopic pregnancy has to be terminated because it will cause the death of the mother if it continues.

After the fertilization, the egg begins its journey, taking several days, maybe as many as 8, 9, 10 days before it finally reaches the end of the journey and is implanted in the wall of the uterus. It divides first two cells, then four cells, and then eight cells. And I would like to pause for just a moment at that eight-cell stage. Imagine now that we are not in the reproductive tract of the female, but we are in a petri dish in the laboratory, because that is what in vitro fertilization means. In vitro means in glass. And they are now taking the egg from the mother and sperm from the father and they have combined these two and produced this fertilized egg, the zygote. It now divides and divides until they come to the eight-cell stage.

At this stage, more than a thousand times worldwide, in one clinic in England more than 600 times, they have taken in the laboratory under the microscope a cell, and sometimes they get two from that eight-cell stage, and they have done what they call a preimplantation genetic diagnosis. They look at the genes, and you can do that, we now know what they ought to look like, and they can determine if there is any genetic defect.

One of those genetic defects is what we call trisomy 21, mongolism. If there is an extra chromosome at the 21st chromosome, you get what we call trisomy 21, or mongolism. If there is no genetic defect in the cell that they analyze, which would be like all the other cells because they began as a single cell here, then they implant what is remaining, that is the six or seven cells that is remaining, and now more than a thousand times worldwide we have had what looks like a perfectly normal baby born from this process.

This technique, which has been widely used in England, is now used in this country; and just outside Washington, here in Virginia, is a clinic that is doing this. They have done it more than 300 times now. Several weeks ago, I talked for perhaps a half-hour with two of their doctors about the procedure.

Let us now take a look at how they get embryonic stem cell lines. They take an embryo in the laboratory which had been produced by the fertilization of an egg, and they let it develop, not to the eight-cell stage, they go just a little beyond that. They go to the inner cell mass, and then they destroy the embryo. And there are now a lot of cells, not just eight; and they take a number of the cells from the inner cell mass, which I indicated previously had all of the genetic potential to produce the body of the baby, but none of the genetic potential to produce the dissidua. And so here we see right at the bottom of this chart we see the dissidua developing there, the little fingers like that are growing into the lining of the uterus.

Well, what this debate is all about, Mr. Speaker, is about the morality, really, the ethics of taking this little embryo, which is a baby in miniature, because, you see, if it goes on just a couple of days later and implants in the uterus, it will become a baby, although it is now in the petri dish in the laboratory, but it can be implanted in the uterus, to take this embryo and to destroy it and take the cells from the inner cell mass to produce a stem cell line. Up to this time that has been the only technique that has been available for developing these stem cell lines.

The President had a very difficult decision to make 4 years ago when there was an interest in using Federal monies to fund further embryonic stem cell research. Maybe we ought to pause for a moment, Mr. Speaker, to look at why we are so much interested in stem cell research. Because these stem cells, as the earlier chart showed, can produce all of the tissues in the body, there is the hope, the promise, and in fact even the realization with some of the work we have done with adult stem cells that we can use these stem cells to replace tissues which have been damaged by disease or some other trauma in the body. We can replace those so as to restore health.

Now, we have a lot of applications from adult stem cells and, as we stand here today, essentially no applications from embryonic stem cells. And why should we have this big debate, Mr. Speaker, about embryonic stem cells when almost all of the applications to medicine have been from adult stem cells? You see, we have been working with adult stem cells for more than three decades, so we have had a lot of opportunity in the medical community to make applications there, but we have been working with embryonic stem cells for only about 6 years, and there just has not been the opportunity to make the medical applications from embryonic stem cells that we have been able to make from adult stem cells.

But because of what embryonic stem cells are, because embryonic stem cells still have all of the capability to produce any and every tissue in the body, doctors and researchers believe intuitively from what they know of embryology that there ought ultimately to be more and better applications from embryonic stem cells than there are from adult stem cells. We do not know. It may be that these embryonic stem cells are going to be like unruly teenagers, very difficult to control. You see, their destiny in life is to divide and divide and divide.

We want them to do that, but we want to be able to control how they divide and what they produce, because if it is a liver the patient needs, you need to convince the cells that is what they ought to be producing, and when they have done enough, they need to quit. They may be very difficult to control. They may keep on dividing, and when you put them in the body, they may form tumors.

Because of what embryonic stem cells do, the medical community and indeed millions of Americans with relatives with devastating diseases believe there are important applications from embryonic stem cells to medicines. We need to provide that opportunity without harming the embryo.

To this date the only way we have gotten these embryonic stem cell lines started is by taking some of the cells from the inner cell mass, which destroys the embryo. In 2001, the President was faced with a very difficult decision. He needed to determine whether Federal funds could be used in embryonic stem cell research when the only way to get embryos at that time was to destroy the embryo.

When the President was making that difficult decision, the scientists at NIH had an open house for Members of Congress and staff to come to NIH and learn about embryonic stem cell research and the potential. I went there, Mr. Speaker, and listened to their presentations. Because in a former life I was privileged to be able to get a Ph.D., a doctor's degree in human physiology, because I taught medical school, because I had a course in advanced embryology, I knew a little bit about what they were talking about.

As I sat there listening to the researchers at NIH explaining what they were doing and the dreams and the hopes that they had for the applications of embryonic stem cell research, and when I thought about the dilemma that the President was in in trying to decide whether it was okay to destroy these embryos to get a stem cell line that may come up with some miraculous cures, I thought back to my studies and to a course that I had in advanced embryology. And really you do not need to have had that course to understand this, but it occurred to me nature had been doing for a very long time what we needed to do, and that is to take cells from the early embryo without hurting the embryo. Nature had been doing that by producing identical twins. In identical twins, half of the cells are taken away from the embryo, and each half goes on to produce a perfectly normal baby. And one of those identical twins is a clone. Think about that and decide how that relates to the dialogue that we are having on cloning.

Well, there are two different times during the development of the embryo, maybe more, but at least two different times that it can split to produce identical twins. One is at the two-cell stage. Instead of just dividing to make four cells, it splits, so there are now two one-cell embryos, and each one goes on to divide and produce a baby. Or it can wait until the inner cell mass stage, and in some embryos there are two inner cell masses, and that can now split to form identical twins.

Sometimes this is not perfect, and they do not split totally, and we have what we call Siamese twins. This is the origin when the split has occurred probably at the inner cell mass stage, and it is not complete, and they remain close enough that some parts of the body grow together.

We know that the embryo is capable of splitting at these two different stages because of the way the babies present themselves at birth. If they are both within the same amniotic sac, they probably split at the two-cell stage. If each have their own amniotic sac, they probably split later.

It occurred to me since nature many times takes half of the cells away from the early embryo and they go on to produce two perfectly normal babies, we ought to be able to take a cell or two from an early embryo without hurting the early embryo. And I asked the scientists at NIH, should we not be able to do it? They said we ought to be able to do it, although we have not done it.

A little after that I was at an event when the President was there, and I mentioned this possibility to the President. He asked Karl Rove to follow up on it, and a few days later I got a call from Karl Rove saying he had talked to the NIH; the NIH told him what I was proposing was not doable.

I said Karl, either they did not understand your question, or there is some confusion, because these are the same people that can take a single cell and take the nucleus out of that cell and put another in it. Of course they can do this. He went back and asked them again, and he came back and said he got the same answer, that they could not do this, and so the President came down with his executive order.

A couple of years after that, not very many months ago, the people from NIH were sitting in my office, and I asked them how could this have happened. What apparently happened as so often happens, there was a miscom- munication. What they told Karl Rove was they were not sure they could produce an embryonic stem cell line from an embryo that early because they had never done it, not that it was not doable. He interpreted this as saying they could not take the cell, and, therefore, the research could not be done.

I would like to spend just a moment looking at some of the reasons why people are so concerned and why this was such an important decision on the part of the President, and why Senator Frist's decision last night has stirred up so much controversy. It is because there are a very large number of diseases that have the potential of being cured ultimately with the application of embryonic stem cell research.

Let me give us one example, and that is diabetes. Kids come in my office with this hockey puck-like thing under their skin, which is an insulin pump. They have to prick their skin to get a glucose level so they can set the pump, and they are very brittle. It has to be pumped in regularly. This is the most expensive disease in our country, and it is potentially totally curable with stem cell applications. All we need to do is produce some islets of Langerhans cells because these are the cells that just happen to be embedded in the pancreas. There is no reason why they need to be in the pancreas. They have nothing to do with the function of the pancreas, because the pancreas is a big digestive gland at the beginning of the small intestine that produces enzymes that digest fats, carbohydrates and proteins. Embedded in the tissue of the gland are what looked like these little islands to Dr. Langerhans, and so we call them the islets of Langerhans. They produce insulin.

Now, insulin does not cure diabetes, as any family who has diabetes in the family knows; it simply delays the course of the disease. There may ultimately be some problems with the eyes and circulation. You lose some toes, they have to be amputated. If we could create islets of Langerhans cells, which could be under the skin anywhere in the body, anywhere that the blood can get to them so the circulation can pick up the hormone that is produced, this should cure the disease.

And there are many others, particularly the autoimmune diseases, and there are 63 autoimmune diseases. These are diseases where the body gets confused what is really body. There is something very interesting that happens with early embryos. Obviously we need to know what is us so foreign things can be rejected. When you get inside your body, there are no bacteria in there. That is a pristine world. We have a big army of white cells in there that make sure that it is pristine. The white cells are told by what we call T-cells as to what is you and what is not you, so they attack what is not you. Sometimes, and in more people than we would like to have it occur in, sometimes the body gets confused as to what is really you.

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