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Adult Stem Cell Research More Successful Than Embryonic

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  • right2life@aol.com
    ... From: The Pro-Life Infonet Weekly Reply-To: Steven Ertelt Subject: Adult Stem Cell Research More
    Message 1 of 1 , Mar 17, 2002
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      From: The Pro-Life Infonet Weekly <infonet@...>
      Reply-To: Steven Ertelt <infonet@...>
      Subject: Adult Stem Cell Research More Successful Than Embryonic
      Source: Do No Harm; March 8, 20002

      Adult Stem Cell Research More Successful Than Embryonic
      by Do No Harm

      [Pro-Life Infonet Note: Do No Harm: The Coalition of Americans for
      Research Ethics is a national coalition of researchers, health care
      professionals, bioethicists, legal professionals, and others dedicated to
      the promotion of scientific research and health care which does not harm
      human life.]

      A report today in the journal Cell, announced by the Associated Press,
      purports to use "therapeutic" cloning to partially correct a genetic based
      immune system defect in mice.

      However, this report comes years after "remedied" adult stem cells - not
      embryonic stem cells - were used to cure human infants of severe combined
      immunodeficiency syndrome, in the first successful clinical trials in
      human gene therapy.

      In the cloning experiments, performed by researchers at the Whitehead
      Institute (W.M. Rideout et al., "Correction of a genetic defect by nuclear
      transplantation and combined cell and gene therapy," Cell Immediate Early
      Publication, published online March 8, 2002) mice with an immune defect
      causing some white blood cells to be missing were cloned, and the cloned
      mouse embryos were destroyed for their stem cells. Since the embryonic
      stem cells were genetically identical to the mice (supposedly to prevent
      transplant rejection), they carried the same genetic defect. The
      researchers used gene therapy to fix the defective gene in the embryonic
      stem cells.

      Several different attempts were then made to correct the immune defect in
      the mice using these stem cells.

      In one experiment, the "repaired" embryonic stem cells were differentiated
      in culture into blood-forming cells and these were transplanted into the
      defective mice. The authors note that this showed little to no success
      (though the data are not shown in the paper).

      Next they tried reducing the number of those cells in the recipient mice
      that were blocking successful transplant. Again, this approach was
      essentially negative (again, the data are not shown in the paper).

      Finally, the researchers transplanted the "repaired" blood-forming cells
      into a different mutant mouse that had the same genetic defect, but also
      lacked the cells that had been destroying the transplanted cells. This
      situation resulted in a modest restoration of the missing blood cells, but
      at less than one-tenth the amounts in normal mice.

      However, the researchers were able to restore normal levels of the missing
      blood cells by first using the "repaired" embryonic stem cells to grow
      born mice, then using the bone marrow stem cells or blood stem cells
      (similar to umbilical cord blood) of those born mice for the transplant.
      In other words, the researchers were most successful when they resorted to
      using adult stem cells.

      The published scientific paper actually shows that the "repaired"
      embryonic stem cells from cloned embryos were unsuccessful in treating the
      gene defect in the mice that provided the donor cells for cloning. The
      authors note: "Our results raise the provocative possibility that even
      genetically matched cells derived by therapeutic cloning may still face
      barriers to effective transplantation for some disorders."

      This study also bears out the enormous global risk to women's health
      entailed in the speculative idea of "therapeutic cloning" to treat
      diseases in humans. Only 1 embryonic stem cell line was successfully
      cultured, starting with 202 cloning attempts. Even if the experiment had
      been successful, the number of human eggs needed for such treatments would
      translate to 303 million human eggs needed to treat the 1.5 million
      Parkinson's patients in the U.S., and over 3.2 billion human eggs needed
      to treat the 16 million diabetes patients in the U.S.

      Far from being a step forward, this report shows that cloning is years
      behind the far more successful advances using adult stem cells, including
      their use to reverse immune deficiencies in humans.

      As reported in April 2000 in the journal Science, French scientists
      restored the immune systems of 3 infants with severe combined
      immunodeficiency (the "bubble boy syndrome") using gene therapy with the
      patients' own bone marrow stem cells. Researchers removed stem cells from
      the infants' bone marrow, added a working copy of the gene to the cells'
      DNA, and injected the repaired stem cells back into the infants. Since
      the procedure used the patients' own cells, there was no problem of
      transplant rejection. After treatment, the numbers and function of the
      patients' immune cells were restored to normal levels, and the children
      were living at home and developing normally with no further treatment (M.
      Cavazzana-Calvo, et al., "Gene Therapy of Human Severe Combined
      Immunodeficiency (SCID)-X1 Disease," Science 288, 669-672, April 28,
      2000).

      Far from showing the supposedly superior benefits of stem cells from
      cloned embryos, the new study shows that this approach continues to lag
      behind adult stem cell advances - even in mice, where embryonic stem cell
      research has been pursued for over twenty years. Adult stem cells are
      successfully treating real human children with serious diseases.

      --
      You can help women with crisis pregnancies choose life-affirming
      alternatives to abortion. Please put a link on your web site to Pregnancy
      Centers Online at http://www.pregnancycenters.org
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