FOR IMMEDIATE RELEASE
August 28, 2000
CONTACT:
Gene Tarne/Michelle Powers (703) 684-8352 (Do No Harm)
NIH
GUIDELINES MISLEADING ON ADULT STEM CELLS
NIH unaware or indifferent to adult stem cell research advances
In
Guidelines issued 8/23/00 for Research Using Human Pluripotent Stem Cells, the
National Institutes for Health (NIH) makes several misleading statements
regarding the potential of adult stem cells for scientific and medical
advancement. The facts on adult stem cell research undermine the NIH’s
rationale for funding destructive human embryonic stem cell research:
NIH:
“[S]tem cells for all cell and tissue types have not yet been found in the
adult human. Significantly, cardiac stem cells or pancreatic islet stem cells
have not been identified in adult humans”
FACT:
Neither have cultured embryonic stem cells been made to differentiate into all
tissue types, including cardiac or pancreatic stem cells.
However, adult stem cells for
these tissues have been identified in
mice, and adult pancreatic stem cells have been used to cure diabetes in mice
(“Reversal of insulin-dependent diabetes using islets generated in vitro from
pancreatic stem cells,” Nature Medicine
6, 278-282, March, 2000). As with
most biological discoveries, animal models have paved the way for clinical uses
in humans and we should expect that these same adult stem cells are present in
humans. Reporting on this adult
pancreatic stem cell research, the British
Medical Journal (BMJ) says: “Early results suggests that ductal tissue
taken from human cadavers can be grown in culture to form functioning islet
cells,” which could lead to harvesting, stimulating and transplanting
pancreatic tissue from diabetic patients themselves. The BMJ reports: “This would not only avoid some of the
risks associated with rejection of foreign tissue but could also potentially end
the need for daily insulin injections.” (BMJ 320:736; 3/18/00).
Moreover,
there are numerous recent reports of adult stem cells being transformed from one
tissue type to another (e.g., bone marrow to liver or nerve; nerve to blood), so
it appears that adult stem cells have the capacity to form many more tissues
than the one from which they are derived (e.g., “Liver from Bone Marrow in
Humans,” Hepatology 32, 11-16, July,
2000; “Adult Bone Marrow Stromal Cells Differentiate into Neural Cells In
Vitro,” Experimental Neurology 164,
247-256; “Turning Brain into Blood: a hematopoietic fate adopted by adult
neural stem cells in vitro,” Science 283,
534-537, 1/22/00). In this respect,
adult stem cells are considered by some researchers (including NIH funded
researchers) to be pluripotent, similar to embryonic stem cells, with the
ability to form any tissue necessary (e.g.,
“Generalized Potential of Adult Neural Stem Cells,” Science
288, 1600-1663, 6/2/00; Adult Rat
and Human Bone Marrow Stromal Cells Differentiate Into Neurons,” Journal
of Neuroscience Research 61:364-370 August, 2000).
NIH:
“[S]tem cells in adults are often present in only minute quantities, are
difficult to isolate and purify, and their numbers may decrease with age...Any
attempt to use stem cells from a patient's own body for treatment would require
that stem cells would first have to be isolated from the patient and then grown
in culture in sufficient numbers to obtain adequate quantities for treatment.”
FACT:
Research is showing these claims not to be true.
In March of this year, researchers in
Philadelphia
identified the conditions to allow large-scale expansion of adult stem cells in
culture, making these cells an almost unlimited resource.
The researchers achieved a billion-fold increase in a few weeks for bone
marrow stem cells in culture. (“Rapid expansion of recycling stem cells in
cultures of plastic-adherent cells from human bone marrow,” Proceedings
of the National Academy of Sciences, 97, 3213-3218, 3/28/2000).
In mid-August, research funded by the NIH itself and the Christopher
Reeve Paralysis Foundation found that adult human bone marrow stem cells can
create a “virtually limitless supply” of nerve cells (“Christopher Reeve
Paralysis Foundation Funds Breakthrough Research,” Press Release of the
Christopher Reeve Paralysis Foundation, 8/14/00).
According to the published research results, the adult stem cells “grow
rapidly in culture, precluding the need for immortalization, and differentiate
into neurons exclusively with use of a simple protocol” (“Adult Rat and
Human Bone Marrow Stromal Cells Differentiate Into Neurons,” Journal
of Neuroscience Research 61:364-370, August 2000).
NIH:
“[B]rain cells from adults that may be neural stem cells have been
obtained only by removing a portion of the
brain of an adult with epilepsy, a complex and invasive procedure that carries
the added risk of further neurological damage.”
FACT:
While obtaining neural stem cells from the brain is a complex procedure, the NIH/Christopher
Reeve Paralysis Foundation funded research demonstrates that adult bone marrow
stem cells can form nerve cells, eliminating the need to isolate such cells from
the patient’s brain: “The marrow cells are readily accessible, overcoming
the risks of obtaining neural stem cells from the brain, and provide a renewable
population. Autologous
transplantation overcomes the ethical and immunological concerns associated with
the use of fetal tissue” (“Adult Rat and Human Bone Marrow Stromal Cells
Differentiate Into Neurons,” Journal of
Neuroscience Research 61:364-370 August, 2000).
In
addition, studies with mice have shown that, given appropriate signals, neural
stem cells do not need to be removed from the brain at all for growth.
Rather, they can be stimulated to regrow while still residing within
the brain. The re-growth could take place even in regions of the adult mammalian
brain that do not normally undergo new cell growth. The researchers report:
“Our results indicate that neural replacement therapies for neurodegenerative
diseases and CNS injury may be possible through manipulation of endogenous
neural precursors in situ”
(“Induction of neurogenesis in the neocortex of mice,” Nature 405, 951-955, 6/22/00).
Again, discoveries in animal models will almost certainly lead to
applications in humans.
NIH:
“[I]n disorders that are caused by a genetic defect, the genetic error likely
would be present in the patient's stem cells, making cells from such a patient
inappropriate for transplantation.”
FACT:
But such transplantation is exactly
what was done for three children in France, as reported in April of this year.
The infants, who had a genetic defect that caused severe
immunodeficiency, had some of their own bone marrow cells removed.
The cells were cultured, the defective gene causing the immuno-deficieny
replaced, and the children were then treated with their own stem cells.
This experiment using adult stem cells appears to be the first successful
instance of a cure by human gene therapy (“Gene Therapy of Severe Combined
Immunodeficiency (SCID)-X1 Disease,” Science
288, 669-672, 4/28/00).
Moreover,
correction of the genetic defect may not always be necessary to effect a cure
with adult stem cells. The British
medical journal Lancet reports
researchers treating systemic lupus (an incurable and sometimes fatal autoimmune
disease) using the patients’ own bone marrow cells.
When transplanted back into the patients, the cells appeared to have
overcome the defect in all patients and repaired organ damage previously
considered permanent. The
scientists noted: “It is mysterious that the transplanted cells, which have
the same genetic defect that made the patients’ immune cells go wrong in the
first place, did not grow up to repeat the mistakes of their siblings”
(“Treatment of severe systemic lupus erythematosus with high-dose chemotherapy
and haemopoietic stem-cell transplantation: a phase I study,” Lancet
356, 701-707, August 2000).
Do
No Harm: The Coalition of Americans for Research Ethics rejects the course of
action taken by the National Institutes for Health to support destructive human
embryonic stem cell research.
Instead, our government should promote adult stem cell research which
protects the inviolability of individuals, rejects harming some for the
potential benefit of others, and holds as much, if not more, promise
of
medical progress.
For more information on adult stem cell progress, please visit our
website at www.stemcellresearch.org
|
