Adult Stem Cells Trump Embryonic – Adult Behind Most of the Success
By Jean Peduzzi-Nelson, The Milwaukee Journal Sentinel, September 3, 2006
The topic of stem cells is a hot issue due to all the vast potential they have, the ethical debates they entail, and the political party alignments that are associated with. Produced by either cloning via somatic cell nuclear transplant or by in vitro fertilization of human eggs, human stem cells can be acquired from human embryos. But they can also be obtain from adults.
Their value in drug testing and disease models, their lack of rejection, their rapid proliferation, their potential to form every cell type and finally, their great promise are the most often stated advantages of embryonic stem cells.
However, these “advantages” are less clear from a medical and scientific point of view. Scientists that either hold key patents or are strongly supported by biotech companies pursuing embryonic cells commercially are the ones that state that embryonic stem cells hold great promise.
The "potential of embryonic stem cells to possibly form every cell type" in the body is remarkable but is of minute clinical significance. The potential to form every cell type is a moot point, as long as a stem/progenitor cell is capable of forming the cell types required for particular injury of disease.
Furthermore, stem cells derived from adults have the same potential as numerous studies have supported. The umbilical cord, bone marrow stromal cells, fat, and the skin are among the many locations in the body that can supply a source of adult stem cells.
The serious problem with embryonic stem cells is actually due to the ability of the cells to quickly proliferate, a quality which is often touted as a quality that makes them so superior. But as obviously seen with weeds in a garden or cancer in the body, rapid growth is not always an enviable quality.
Rats injected with embryonic stem cells, in an animal model of Parkinson’s disease, showed a minor benefit of about 50%. However, the embryonic stem cells caused brain tumors in one-fifth of the rats which lead to their death.
It is true that embryonic stem cells are not rejected, but saying that there is a lack of rejection is shrewdly deceptive. The cells must mature into a particular type of cell to be functional in therapy. The immune system recognizes cells that have matured as foreign objects and they are then rejected. Thus, some scientists argue this dilemma as a reason for human cloning so the rejection of embryonic stem cells can be avoided, but cloning carries its own set of problems and moral dilemmas.
Only a few studies have been conducted in animal experiments to exhibit the viability of this and so the field is still in its infancy. Chasing this extreme measure when the human body is full of stem/progenitor cells that would not be rejected is one of the most absurd directions ever observed in the history of science that is purportedly being promoted to help people.
Tissue models and drugs need to be tested on mature tissue not embryonic cells, so the “usefulness in drug testing and disease models” is not a sensible claim. Tissue culture model systems of muscle, skin, etc are plentiful and regularly used in drug and disease models.
Virtually unknown to the American public are the advantages of adult stem cells. It is embryonic stem cell treatment that is most profitable, and not the best, that is getting all the exposure.
The safest cell option for people, one of the greatest advantages of adult stem cells is that it is usually possible for a person to use his or her own stem cells. Uncontrolled growth, chromosomal abnormalities, disease transmission and rejection problems are all eliminated with adult stem cells.
Rarely mentioned is that methods have yet to be developed to grow embryonic cells in a manner that does not induce significant chromosomal abnormalities.
The record for adult stem cells compared to embryonic stem cells is exceptionally impressive if one looks at human clinical trials or research using experimental animals.
In examining only the scientific evidence, one wonders why the controversy even exists.
Let’s first take a look at Parkinson’s disease. The stem/progenitor cells are the only cells that survive when a transplant consists of embryonic/fetal tissue. It is thought that as a consequence of cellular overgrowth or from rejection of the foreign cells/tissue derived from embryo or fetus, devastating deterioration at one year after treatment occurred in about 15% of patients in two clinical trials using embryonic/fetal tissue.
A patient who received his own adult stem cells got results that were in striking contrast, he had almost full recovery for several years after the transplant.
In an animal model for Parkinson’s, human embryonic stem cells did not cause any improvement and actually caused tumor formation. The use of growth factors in treating Parkinson’s is another position supporters of embryonic stem cells try to push.
Diabetes is like Parkinson’s in the regard that it is a disease, so a dissipation of symptoms for several years rather than a cure is the most likely scenario when treating with stem cells. Recently, after receiving stem cells from her mother, it was reported that a girl afflicted with diabetes gained insulin independence.
Blocking the autoimmune response can reverse diabetes in mice which is an encouraging result in animal studies. There are also several reports that adult stem cells can develop into insulin-secreting cells.
In regards to spinal cord injury, there is an even more dramatic comparison between adult and embryonic stem cells. Extensive web coverage and the front page of many newspapers were dedicated to mice receiving embryonic stem cells. However almost total recovery from complete paralysis was observed in rats using adult stem cells from bone marrow, these results were published in a paper by Zurita and Vaqueo. Resulting in improvement for people with severe and chronic spinal cord injury, transplants of tissue containing one’s own stem cells is safe.
Looking at heart disease, adult stem cells derived from bone marrow have provided reported benefits in several studies involving patients with heart attacks. After using one’s own adult stem cells in treatment, clinical trials have also shown improvements in some patients with heart failure.
Similar comparisons can be made for a variety of diseases and injuries. But headlines will never be written nor will the majority of the American public ever hear of these successes with adult stem cells.
The results with adult stem cells will eventually end the controversy that should never have existed in the first place, although it may take years for these adult stem cells treatments to become commonly available.