By Reason McLucus
The news media are ignoring a major medical revolution. Doctors and scientists have been making major strides in the fields of tissue engineering and regenerative medicine in the last decade. Journalists write news stories about embryonic stem cells which only promise to be useful sometime in the distant future and ignore the fact that doctors have been using adult stem cells to grow bones and treat various disorders for years.
Harvard University’s Dr. Joseph P. Vacanti http://www.celltx.org/2004/vacanti.htmand his brother Dr. Charles A. Vacanti http://www.brighamandwomens.org/publicaffairs/Newsreleases/charlesvacanti.asp have been among the leaders in this field. Joseph Vacanti began working on the idea in the seventies, but didn’t isolate human adult stem cells until1992..
Most cells can only reproduce a limited number of times. Small sections of DNA at the ends of chromosomes called telomeres become shorter with each division. The loss of these telomeres prevents further division. Stem cells don’t have this problem.
Specialized cells normally only produce daughter cells like themselves. Stem cells are flexible and can often produce a variety of different cell types.
By 1994 the Vacantis were ready to work with Dr. Joseph Upton and Dr. Dennis P. Lund at Boston Children’s Hospital to grow a chest for 12-year-old Sean G. McCormack of Norwood, Mass. McCormack was born with Poland’s Syndrome and had no cartilage or bone under the skin on the left side of his chest. McCormack was an active boy and wanted to play baseball even though his condition made such activity risky.
The doctors scraped away protruding cartilage
from McCormack and used the cells to seed a biogradable scaffold composed
of artificial polymer that was molded to the shape of his torso. Dr. Yilin
Cao assisted by adding growth factors to the cells before “cooking”
them in a bioreactor for several weeks. After receiving special approval
from the Food & Drug Administration, the doctors implanted the engineered
cartilage into McCormack. (http://www.businessweek.com/1998/30/b3588001.htm)
Charles Vacanti has also grown thumbs and ear lobes.
Recently German doctors grew a new jaw bone for a 56-year-old German man whose lower jaw and half his tongue were cut out a decade ago because of mouth cancer.
Doctors couldn’t use the normal approach of taking a piece of bone from some other location because the man was taking blood thinner for another medical condition. Artificial jaws would have posed too great a risk of infection.
Dr. Patrick Warnke and his team began by creating a virtual jaw on a computer based on a 3-dimensional scan of the patient’s mouth. They next created a thin titanium micro-mesh cage. Sugar lump sized bone mineral blocks were placed in the cage along with human growth factor for building bone and blood extracted from the man’s bone marrow.
The surgeons implanted the cage into the muscle below the man’s right shoulder blade and left it there for a few months. They then removed it along with some surrounding muscle and blood vessels and implanted it in the man’s mouth with connections to blood vessels in the patient’s neck. http://start.earthlink.net/newsarticle?cat=0&aid=D84N93580_story
Plastic scaffolds can also be used to grow new cells in the patient’s body. In early 1998 a surgeon repaired a large hernia I had by placing a plastic scaffold across the gap. My stem cells then generated new muscle cells along that scaffold.
Charles Vacanti wasn’t the first to grow new human tissue for patients. During World War I Dr. Harold Delf Gillies used tissue from other parts of the body to repair war injuries. He developed the tubed pedicle graft to facilitate new tissue growth. This procedure involved maintaining blood vessel connections to the new tissue until new blood vessels developed.
This procedure was particularly useful for growing new skin cells. Human skin cells are constantly replaced with new cells working their way up to the surface as old skin cells die and fall off. The use of the tubed pedicul graft technique allowed growth of new skin cells in areas where skin was still healthy to be transplanted to areas where it had been destroyed. I can recall seeing new skin growing as a kind of tube on my grandfather’s neck back in the 50's. The skin was then used to replace facial skin that had been destroyed by skin cancer.
Skin grafts themselves aren’t a recent invention. Hindu accounts report the use of skin grafts as early as 3000 B.C. http://www.findarticles.com/p/articles/mi_m0PDG/is_3_1/ai_110220336
Today various forms of “artificial skin” are available with some using human tissue such as the product called Apligraf [ http://www.apligraf.com/ ] that uses the foreskin taken from infants to produce a type of “skin” that can be used for burn victims.
Cornea transplants are the most common transplants from one person to another. Over 700,000 people have received cornea transplants since 1961. http://www.donors1.org/donation/history.html
The first was attempted by Richard Kissam in 1838, but the cornea soon became opaque. Various other attempts also failed until Conrad Zirm succeeded in 1905. http://www.freewebs.com/scientific_anti_vivisectionism5/corneatransplants.htm
As with other transplant surgery the number of people who need corneas exceeds the supply of corneas available for transplant the June 2, 1999, issue of the New England Journal of Medicine reported on a Japanese study that supplemented cornea transplants with adult stem cells. Today, doctors are using adult stem cells to grow new corneas for transplant.
Cancer treatment is one of the biggest uses of stem cells. Curing some forms of cancer requires using radiation to kill the blood producing stem cells in the bone marrow. Bone marrow transplants(adult stem cells) are then used to replace the destroyed cells. Similar procedures are being investigated for autoimmune disorders.
For example, Methodist Hospital in Houston, Texas, and other locations have tested this treatment for Multiple Sclerosis. Other variations have involved reeducating the patient’s immune system cells in experimental treatment for Lupus. Stem cells are removed from the patient before zapping the immune system. The reeducated cells are then injected back into the patient. http://www.sciencedaily.com/releases/2004/05/040517073421.htm
Immune suppression combined with partial pancreas transplants has been used successfully in experimental treatment of diabetes. In this procedure a donor pancreas was divided among multiple recipients whose immune systems had been treated.http://www.sciencedaily.com/releases/2004/02/040224104659.htmScientists have discovered how to produce new pancreas cells from adult stem cells.
http://www.stemcellresearch.org/pr/pr_2001-04-27.htmSpontaneous generation of insulin producing cells has been observed in mice whose immune systems were suppressed. http://www.news.harvard.edu/gazette/2001/08.16/01-stemcells.html
Gene replacement therapy is being combined with stem cell treatments for Muscular Dystrophy.
Scientists once thought bone marrow stem cells were only useful for producing blood cells. However, scientists now know that bone marrow cells can be used to produce brain cells that could be transplanted into the brain as well as providing new liver cells.
It has been known for some time that the liver can regenerate. This capacity allows partial liver transplants in which the new liver then expands, including partial livers provided by living donors.
The development of new corneas and bones demonstrate one of the types of treatments the Vacantis believe adult stem cells can be used for. Doctors in the field of regenerative medicine believe they extend such procedures to grow new internal organs such as kidneys and the pancreas.
Other treatments involve repairing existing body parts in place. Doctors have begun injecting a patient’s own stem cells into the heart where they begin replacing damaged tissues. http://news.bbc.co.uk/2/hi/health/3877877.stm
Other doctors are looking for the proteins that signal for replacement cells such as the gene that codes for stromal cell-derived factor-1(SDF-1). http://www.clevelandclinic.org/heartcenter/pub/news/archive/2003/stemcell9_09.asp
These doctors believe that they may be able to get the body to repair itself by injecting this protein into a damaged heart, for example, they can trigger heart repairs. This particular gene is also of interest to diabetes researchers who have found that many Americans who have Type 1 Diabetes have a defective copy of this gene. http://www.findarticles.com/p/articles/mi_m0922/is_5_50/ai_80392788
However, this defect hasn’t found in Japanese with Type 1 Diabetes. Conceivably a defective copy of a gene that normally signals for repairs could trigger the body’s immune system to destroy cells.
Spinal cord injuries are also being treated with adult stem cells. Laura Dominguez of San Antonio, Texas, and others have benefitted from the treatment provided by Dr. Carlos Lima at the Egas Moniz Hospital, in Lisbon, Portugal. Lima harvests stem cells from the patient’s nose and inserts them into the sites of spinal cord breaks. http://www.stemcellresearch.org/testimony/dominguez.htm
Doctors have discovered how to repair damaged lung cells using adult stem cells.http://www.sciencedaily.com/releases/2003/09/030901091237.htmDentists are working on a way to use adult stem cells to grow new teeth at the appropriate location in a patient’s mouth. http://www.nydailynews.com/city_life/health/story/45934p-43224c.html
A medical revolution is occurring using adult stem cells to repair or completely replace damaged tissues. Unfortunately, some researchers want to slow this revolution by diverting the inadequate amount of research funds to development of embryonic stem cells. They claim that embryonic cells are needed because they believe adult stem cells cannot be used to produce all the various cell types.
This belief persists in spite of the fact that all the major cell types(skin, muscle, nerve(glial and neuron), blood and bone) can already be produced from adult stem cells as can more specialized cells such as pancreas, kidney, cornea and lung. Moreover many of these cells are already being used to treat patients as the above discussion indicates.
Duke University researchers have even discovered that a significant portion of the adipose fat cells most of us have too many of can be converted into nerve and other cells. The ability of fat cells to function as stem cells may explain why obese people have more trouble with heart and other problems. The use of their stem cells to store fat may prevent them from producing cells to replace damaged cells in the heart or other areas.http://www.sciencedaily.com/releases/2004/06/040604030545.htm
Dr. Steven Goldman has led a team of researchers at the University of Rochester Medical Center to turn ordinary cells into stem cells by introducing a telomerase gene. The presence of this gene allows the cells to reproduce indefinitely because the telomerase gene replaces the telomeres that normally become shorter as cells divide.
The FDA has recently approved human trials by Massachusetts General Hospital of an adult stem cell therapy that has reversed Type I(Juvenile) diabetes in mice. A team led by Harvard’s Dr. Denise Faustman has successfully(92% success rate) used adult spleen cells to retrain the immune systems of diabetic mice to stop the immune system attacks on insulin-producing pancreas cells. http://www.stemcellresearch.org/pr/pr_2004-08-20.htm
Lee Iacocca’s foundation has donated $1 million of the possible $11 million that will be needed for the trial. Unfortunately some major foundations like the Juvenile Diabetes Foundation are using money to support embryonic research instead. http://www.latimes.com/news/local/la-me-stem31aug31.story
The claim by embryonic researchers that all research should be financed ignores the fact that research funds are very limited. Why spend money on embryonic research that may never be useful in humans instead of adult stem cell research that is already producing results?
Adult stem cells are successfully treating people now for spinal cord injuries and Parkinson’s. Why spend money on embryonic research when researchers are still having trouble managing embryonic cells? Some embryonic cells have produced tumors. The March 25, 2004, issue of the New England Journal of Medicine contained an article indicating that some embryonic cells are producing cells with extra chromosomes.
Why should patients have to wait for embryonic researchers to duplicate the work of adult stem cell researchers before receiving treatments? Testing new treatments can take several years and embryonic research isn’t even ready to consider clinical trials. Some treatments with adult stem cells, particularly for cancer, are already available to the general public. Additional treatments will be available within a few years if they work. Embryonic treatments cannot realistically be expected to be available for at least 5 to 10 years if not longer.
So, why should people have to wait? Why
not provide full funding to adult stem cell therapies now instead of splitting
money with embryonic research that may never produce results?
In the early days of micro computers some programmers would distribute their programs as shareware. People could try the program out before deciding whether to send money to the progammer. This same procedure can be used by writers on the Internet. Readers can decide after reading something whether it is worth paying for and how much to pay for it. One way to do so is through PayPal.