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Monday, January 26, 2009

Embryonic stem cell hype and spin (REVISED)

Most of the articles you are probably reading about embryonic stem cells will be cheerful about how these companies are using embryonic stem cells to make people with spinal cord injuries to walk.

There will also be the usual "Bad Bush stopped this because he hated science" (or the variation "because those big bad right wing fundamentalists objected).

But the hype isn't quite true.

Stem cells have been used to cure people for years: adult stem cells, that is.

As for "embryonic stem cells", there are ways that these could be obtained that makes them morally acceptable for Catholics.

One can get embryonic stem cells from ectopic pregnancies (Miscarriage embryos are often too "old" to use). Or they could be derived from amniotic fluid, from Umbillical cords, or from biopsy of the placenta that is commonly done to diagnose defects in the first trimester.

And, of course, more recently, scientists have figured out how to make adult stem cells "revert" to embryonic like stem cells, and indeed various experiments have already been done with these stem cells, which are cheap and more abundent, and an identical "match" to the person needing treatment.

But apparantly the Geron stem cells come from "left over" "embryos".

The argument is that these "left over embryos" will be discarded (read die a natural death) anyway, so why not use them.

But the dirty little secret is that few couples actually donate such embryos, and old embryos aren't desirable for research. That's why the company behind todays' headline, Geron, is busy trying to get California to allow to pay for the fresh eggs to make new embryos.

A "fresh" egg in the US costs $5000 plus dollars, a lot of us in the third world worry that again poor people in Indian and the Philippines will be enticed into selling body parts (in this case being given medicines to "superovulate" numerous eggs). The "complication" rate in the US is low, but under third world conditions, even those "minor" complications (e.g. infections) could be fatal.

But the main ethical issue here is that Catholics and others see such embryos as humans, and that destroying them is the same as killing a human being.

Others see the life as human life, but nevertheless are disturbed by the callusness of experimenting on human life: even if they see the embryos (actually pre embryos) as having less dignity than fully formed humans, they still are disturbed about experiments that view potential human life as merely something for scientists to experiment on.

In this case, the cells have been transformed and grown in the laboratory, making the cells "derived" from embryos (which die in the process of removing the stem cells).

It's that last part-- the killing of embryos to get stem cells from them, that is ethically abhorant to Catholics and others, but the cells themselves now are distant from the illicit act, having been growing in laboratories for many months.

So, could a Catholic morally use such a treatment if it cured his loved one?

Ah, there's the problem. But it is not exactly a "new" moral dilemma.

At least one childhood vaccines was originally developed from theraputic abortions of children with that virus, but many years have passed since their development, so the Vatican has allowed Catholics to use the vaccines until another source is available.

But in this case, there are other sources of cells to use that probably would work just as well, so ethically it is just plain wrong.

But the interesting part of the "experiment" is that although the hype says they are trying to regrow the injured spinal cord, they are not using immature nerve stem cells, but stem cells that are programmed to grow into the lining cells that coat the nerve cells.

According to Web MD, they took embryonic stem cells, processed them and in the lab made the "precursor cells" that are supposed to grow into "oligodendrocytes -- the cells that make up the myelin sheaths that coat nerves in the spinal cord."

This brings up all sorts of questions:

Will these lining cells turn into oligodendrites, or into nerve cells? Will they merely protect the nerves so that the nerves will regrow, or will they form a "scaffold" so that the person's own nerve cells will regrow? And will the nerves actually regrow?

There are other experiments using various methods to get the person's own nerve cells to grow using "scaffolds" that allow them to pass by the injured area: using liquid scaffolds, or biosynthetic scaffolds, or even "nanofibers".

So do precursor stem cells of "oligodendrites" have an advantage over other experiemental treatments?

Will the precursor oligodendrites help the nerves to grow correctly? Or will the nerve cells grow into a tangle of nerve cells (something that sometimes happens when you cut a skin nerve). Will these cells actually allow the person's own nerve cells to regenerate or grow up the spinal cord (or down from the brain into the Spinal cord, since many spinal cord cells are located in the brain and "synapse" in the cord).

And if they do grow, will they connect correctly? Just putting in nerve cells is like just putting in electrical wires: They don't do much good unless they go where you want them to, and they have to connect to the right places so that they work properly.

Then you have more questions: Will the "transplanted" cells be tolerated by the recipient? Or will the patient have to take rejection drugs to stop the body from destroying them via the rejection process, a problem that one sees with most organ donations.

Finally, there is the question of cancer, overgrowth, and benign tumors.

Previous studies transplanting embryonic cells into human brains for Parkinsons' disease did improve a few people, but most didn't work very long: And in a few cases, the cells "overgrew" and resulted in tumors, and in other experiments, the cells overgrew and the patients developed spasms that was worse than their original Parkinsonian slow movements.

If the cells should "overgrow", you could end up with tumors or even cancer.

Or the cells could overgrowtangled and result in the person in severe pain from neuromas.

Or the cells could grow wrong and result in the person having uncontrolled movements.

Finally, although the company claims that they have lots of success, I'm waiting for the animal studies to show that they took embryonic animal stem cells and placed them into animals with spinal cord injuries, and they made the animals walk again. Yes, there are rat studies. But what about primate studies first?

The irony about "primate studies" is that if you experiment on monkeys, you'll get your home firebombed, whereas if you merely kill an embryo that could become a baby, and use it's cells to experiment on handicapped humans, you are a hero.

Despite the hype, these first studies are supposed to be only to see if the treatment is "safe" for humans, so they will not be given a large dose of cells. If the cells don't harm the recipient, they will then be given a larger dose of the cells to see if the cells regrow the spinal cord.

Even if these experiments work, it will be years until the "treatment" will be ready to use in people who are not guinea pigs for the company.

But of course, you wouldn't know that if you just read the hype.

In the meanwhile, experiments with adult stem cells, including matching "patient derived" stem cells and other techniques will receive less publicity.
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(an earlier version of this post was corrected: The stem cells come from ivf not abortions)

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2 Comments:

  • Are you sure they are using the fetal tissue? I read the Web MD site you included and there was no mention of fetal tissue. Did I miss something.

    By Blogger Greg, at 11:29 PM  

  • This is all a great thing for research as long as we are using embryonic stem cells ESC's that will be discarded anyway, but not at the cost of a life. To date we still have not seen any real progress with ESC's when implanted in a living human organ, too many chance for tumor growth and more.
    On the contrary we have seen many results with Adult Stem Cells ASC in our own bodies. There are numerous peer review studies showing results with no ethical issues. A new product on the market an all natural biotical extract that will release 3 - 4 million ASC within one hour from consumption from your bone marrow. As we all know stem cells is the body's natural way to renew, rebuild itself. "Google me" or visit this web site and I will send any scientific documents to back this up. www.adultstemcellsrelease.com

    By Blogger Ray mumme, at 12:17 AM  

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