Adult stem cells dead end

The claim that adult stem cells hold the same medical potential as embryonic stem cells is a distortion of the science by some individuals and groups with a political agenda because adult stem cells may never prove as useful as their embryonic counterparts, experts tell United Press International.

Embryonic stem cells give rise to all the different cell types in the body and thus have the potential to replace damaged tissues and treat diseases such as diabetes, Parkinson's and neural paralysis. However, some groups have opposed the research because it requires the destruction of embryos to harvest the stem cells.

Recently, these opponents, led by Senator Sam Brownback, R-Kan., have claimed scientific studies show adult stem cells -- which can be isolated from bone marrow, the brain and perhaps other tissues in adults without the destruction of an embryo -- can, just as embryonic stem cells, give rise to every cell type in the body.

However, no study has ever shown that to be true, Irving Weissman, an adult stem cell researcher at the Stanford University Medical Center in Palo Alto, Calif., told UPI. Although adult stem cells initially appeared promising, Weissman said, a review of the studies suggesting that promise reveals sloppy and questionable science and casts doubts on claims about the cells' disease-treating potential.

Opponents have a right to object to embryonic stem cell research for moral or religious reasons but they do not understand the science, Weissman said. "This is a group of people who have a political objective and who don't know what the scientific standards are," he said.

Brownback and a group called Do No Harm have been some of the most vocal proponents of adult stem cells, often issuing statements highlighting studies supporting the potential of adult stem cells while ignoring other research showing their limitations.

"Brownback is interpreting research data that he does not have the background to interpret," Weissman said, noting he once had to explain to Brownback during a Senate hearing that New Scientist was not a scientific journal but a commercial magazine.

Do No Harm sent a letter last year to President Bush and Ruth Kirschstein, acting director of the National Institutes of Health at the time, claiming the potential of adult stem cells to treat disease "is as great as or greater than the potential offered by human embryonic stem cell research." The group cited 228 scientific studies they said showed the potential of adult stem cells to give rise to various cell types in the body and treat disease.

Weissman was commissioned by the American Association of Medical Colleges to review all of those studies and he concluded none of them proved adult stem cells could produce other tissues. The studies failed to meet basic scientific criteria and most of them did not even show they were starting with stem cells to begin with, he said. Others did not show the cells they began with were human and still others failed to prove the material they started with was capable of giving rise to other cell types.

Weissman said he has co-founded three adult stem cell companies and as such does not have an undue bias against the potential of the cells. But he suggested if the embryonic stem cell opponents do not accept his review, then they should request an independent third party, such as the Institute of Medicine -- part of the National Academy of Sciences in Washington -- review the studies objectively.

Douglas Melton, an embryonic stem cell researcher at Harvard University who reviewed many of the papers with Weissman, said in addition to the other problems cited, many of the studies did not account for the "artifact of fusion." This is the process by which a stem cell fuses with another cell type, thus making it appear as though the stem cell has engendered a new cell when in fact it has not. If a stem cell does not give rise to a new cell, then it cannot be used to treat disease.

"It appears now that there's really convincing evidence that the end product (of many of the adult stem cell studies) was confused by the product of cell fusion," Melton told UPI. "There's incontrovertible evidence that embryonic stem cells can make all the tissues of the body and no evidence that adult stem cells can do that," he added.

"Scientists are starting to get more cautious about those earlier claims" about the potential of adult stem cells, Weissman said. "They want more proof that these cells can become something else."

Robert Lanza, vice president of medical and scientific development at Advanced Cell Technology Inc., of Worcester, Mass., which is developing therapeutic techniques based on embryonic stem cells, agreed adult stem cells do not hold the same potential as embryonic stem cells.

"Anybody who is in this field knows the difference," Lanza told UPI. "It's certainly premature to think they can become all the different cell types. Even if they can, it doesn't mean they can be used to treat disease."

Lanza acknowledged adult stem cells have a limited ability to become other cell types, but he pointed out they generally only give rise to cells of the organ from which they were isolated from, such as blood stem cells giving rise to components of the blood.

"My concern and many of us in the scientific community's concern is that is a far cry from having a type of cell that can become all the different cell types," Lanza said, which means these cells may only have a limited use, if any, for treating disease.

A type of adult stem cell called a hematopoietic stem cell is often cited by Brownback and others as having the potential to become other tissues in the body. These cells, which are derived from the bone marrow, give rise to components of the blood under normal circumstances but some proponents have suggested under the right conditions they could become brain cells and heart cells. However, Weissman recently conducted a study that found these particular adult stem cells do not become much else other than components of the blood.

One argument opponents use for abandoning embryonic stem cell research is these cells have not been shown to cure any disease and they can give rise to tumors. Weissman does not dispute this claim, saying, "There needs to be a lot of research before we can find out if (embryonic stem cells) will be suitable or not." But he noted it is essential that both lines of stem cell research -- embryonic and adult -- proceed because it is too early to say either one holds all the answers for treating disease.

Do No Harm issued a statement recently saying a study finding adult stem cells found in the bone marrow could give rise to many other tissue types in mice proved adult stem cells had the same potential as embryonic stem cells. However, the group failed to point out the type of cell used in the study is extremely rare and the scientist who conducted the study herself admitted the cells had not shown function or the ability to replace diseased cells. She also said embryonic stem cell research should continue because both fields may wind up being beneficial to people.

Lanza said the cells used in the study cited by Do No Harm may never prove suitable for treating disease. The type of cells used in the study "have limited clinical potential," he said. Because they are so rare, "those types of cells are going to be difficult if not impossible to grow in large enough quantities to be feasible to treat disease," he said.

Much has been made about the mounting evidence of the potential of a type stem cell from fat tissue to become other cell types and treat disease. But Weissman said he has been in contact with some of the researchers working with these fat stem cells and offered to confirm their results if they would send him a sample of their cells. So far, the researchers have refused, an act of secrecy that raises doubts in the open world of science that prides itself on confirming results rather than just blindly accepting them.

All three scientists agreed that members of Congress are letting politics cloud their judgment and distort the science of stem cells, which could lead to erroneous legislative decisions that deprive patients of treatments that could save lives. "Much of this is being held hostage by abortion politics ... It's not the medical scientific viewpoint," Lanza said.

The House has passed a bill that bans therapeutic cloning -- a technique that seeks to create embryonic stem cells for treating disease. The Senate has yet to vote on the issue. Last year President Bush limited the types of embryonic stem cells that could be used for research and the Senate will hold a hearing this week to look at how the decision is impeding progress in that area.

Distorting or misinterpreting the scientific research "is a very pervasive problem in this area," said Ronald Green, a professor of religion and director of the ethics institute at Dartmouth College who has closely followed the stem cell debate.

"What some of the politicians lack is the understanding of the process of science," Green told UPI. "They will pick up a handful of reports of the plasticity of adult stem cells and state that this is a sufficient line of research without realizing that the next report could reverse that or show some other problem like cell fusion."

Green noted if politicians "were serious about this at the legislative level, they would listen to the scientific community as a whole, interrogate the scientists, listen to their disagreements and not just try to take some headline in a science newspaper and make that the basis of their decision."

The danger of that kind of one-sided approach could be life-or-death, Green said. "Delaying this research may be the difference of declining somebody's life," he said. "We could go down the road with adult stem cells and could find out they don't pan out." It is a race against time in many people's lives, he said.

Lanza agreed, pointing out 3,000 Americans die every day from diseases that embryonic stem cell research potentially could treat. "A lot of people are going to die should (adult stem cells) not pan out," he said. Blocking embryonic stem cell research is "like going into battle with one hand tied behind your back."

A blastocyst isn't a 'you.'

I'm in agreement with you here. However, by 8 weeks of development you ARE you. All the basic strutures are in place, the only have yet to mature. I have completely changed my stance on abortion since starting medical school.

Medicine defines the "embryonic" stage as that between 3 and 8 weeks. After 8 weeks we call it a "fetus".

I personally have no problem with early stem cells from the pre-embryonic period, which is where almost all "stem cells" come from, especially when many of these conceptuses would be destroyed anyway. At this stage, mostly a simple mass of cells, I don't see anything descriptive of a "human."

You wouldnt want to use miscarried fetuses for that becuase they often miscarry for genetic reasons.

There's no easy answer -- either you have to utilize the deaths of developing human beings, or you gotta suck it up and realize that, sure, scientifically, there are things we can do, but morally should not, until such time as we might be able to extract them without killing human beings.

But, aren't you an atheist? You don't understand anything beyond this world anyway

Watch it. It is more complex than that. The alpha and omega of the issue of stem cell reseach is not all about theology. At least not to me. But then you already knew that. I know these threads are conducive to little bon mots, but here I felt I should weigh in. Cheers.

Prove it.

Well, let's see . . . does the blastocyst have a brain - do you? Does the blastocyst have other working organs - do you? Does the blastocyst have arms, legs, and the basic morphology of a human - do you? Look at the dichotomy and then why don't you try to "prove" that a bastocyst is a "you".

Is it genetically unique?

Sorry folks, the burden of proof must be to first prove the negative: that it is not a person.

You have all those parts you mentioned yet I cannot prove that you have a soul, and I cannot prove to you that I have one.

the burden of proof must be to first prove the negative: that it is not a person.

That's why these "prove it" arguments are silly and juvenile, besides I already pointed out a few things that makes a person a "person". A blastocyst has none of these.

So someone without the correct morphology is not a person?

Even people with anamalous or deviant morphology still follow the basic human plan. Try putting words and ideas into someone else's mouth.

You could have saved us both a little time by just saying up front that you don't wish to discuss it.

Your nifty example, that at 7.995 weeks a bunch of cells is not a person but that at 8.001 weeks it is a person... is just as laughable as my "juvenile" observations.
When that moment of inspiration happens, as the "blastocyst" transitions magically into a "fetus" over the period of mere seconds... what does the mother feel? Does she notice? Oops... before those magical few seconds occur she isn't actually a mother. My bad.

Nevermind.

I never said that development happens over mere seconds. It takes about 5 weeks to go from bilaminar germ disc to fetus (an amzaing process speaking great volumes to Him that created us). Also, I never said there was anything magical about week 8 outside of the fact that after week 8, medically, we call the conceptus a "fetus". A blastocyst is just that a "blastocyst" - no brain, no organs, no arms, no legs, etc. - just a clump of cells. Nothing is "human" as we know life as humans outside of a Chromosome number. The blastocyst doesn't think, feel, or love - need brain development for this. The blastocyst doesn't bleed or feel pain - need nerves and vessels for that. These structures are not completely present until about week 8, up until the point these structures are developing and after that point these structure mature. This isn't some kind of nefarious plot to lessen the sanctity of life - it's basic human development.

Sometimes the cure is worse than the disease. Cloning of humans and ebryonic research reach that level as far as I am concerned.

I just don't see a compromise that could work.

I just don't see a compromise that could work.

You're right. There won't be one. The work
will go on, though, and we will all benefit
from its fruits. Of course, there is the Amish...

Now you are into using arbitrary definitions to justify a moral standard.

Doesn't work.

It's just like saying "a slave is not really human", or "Jews are not part of the Master Race, therefore it's OK to dispose of them".

Some people - many people actually - will use any excuse to murder.

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