We spoke about regenerative medicine (using cellular treatments to repair injured or damaged organs), the science of human cloning (how mammalian cloning is accomplished), and the crucial moral issues raised by cloning humans, such as the potential consequences of treating the creation of human life as a matter of mere manufacture.
We also spent a great deal of time discussing the many advances being made in using adult stem cells as efficacious and morally non-controversial sources for regenerative medical treatments. Indeed, we devoted nearly one third of the more than two-hour event to contrasting the many exciting adult stem cell research breakthroughs compared with the relative paucity of embryonic stem cell successes and the virtually non-existent advances in therapeutic cloning research.
Adult stem cell therapy would be almost magical. (A good analogy might be the common practice of donating your own blood for later use in your own surgery.) Instead of taking drugs to treat degenerative ailments such as Parkinson's disease or undergoing organ transplant surgery, if adult stem cell therapy works the way researchers hope, doctors would be able to harness the patient's own cells as potent medicine to rebuild damaged organs and body tissues. For example, a heart attack patient's bone marrow stem cells might be extracted, proliferated in culture, and then injected back into the patient resulting in the heart restoring health to damaged tissue.
EMBRYONIC STEM CELLS are another potential source for regenerative treatments. But, we pointed out, unlike adult stem cell treatments, ES cells cannot be used in human studies because of two fundamental safety issues. First, they cause tumors in animal studies. For example, in one recent experiment, ES cells were injected into a mouse in the hope they would rebuild the animal's damaged knee. Instead, the cells obliterated the knee by stimulating tumor growth. (More recently, an adult stem cell animal study successfully rebuilt joints without causing tumors.)
Second, using embryonic stem cells as a regenerative treatment--unlike adult stem cells--would introduce foreign tissues into the patient, perhaps stimulating the immune system to reject the tissues. "Therapeutic cloning" is supposed to get around this problem. The complicated procedure would involve the manufacture of cloned embryos of the patient who is to receive the stem cell treatment. The cloned embryos would be developed for one week to the blastocyst stage. At that point, they would be destroyed, and their embryonic stem cells harvested. (To date, researchers have been unable to successfully create cloned human embryos to the blastocyst stage.) These would then be proliferated in culture and eventually injected into the patient, the hope being that the tissues would not be rejected because the DNA from the cloned embryo and that of the patient would be nearly identical.
THE SEMINAR in which we addressed these and other issues was covered by the Louisville Courier-Journal. The resulting story ("Cloning Opponents to Make Major Push to Ban Research," November 23, 2003) never reported the actual content of our respective presentations. Instead, in a curious journalistic approach, cloning supporters from the Universities of Kentucky and Louisville were quoted extensively rebutting our wholly unreported remarks.
Most egregiously, despite our having emphasized adult stem cell therapies as an efficacious and less expensive alternative to therapeutic cloning, despite extensive citations referenced by Dr. Prentice from the voluminous successful adult stem cell experiments that have been published in the world's most prestigious peer-reviewed science journals, the Courier-Journal story contained not one word about adult stem cell research. Instead, readers were told that therapeutic cloning is the potential source of "treatments for diseases that afflict more than 100 million Americans," including "replacing malfunctioning neurons in the brain of a Parkinson's patient, adding insulin replacing pancreatic cells in diabetics and infusing muscle cells into the heart damaged by heart attack."
SADLY, this experience is typical of the establishment media's general approach of either not reporting or under emphasizing adult stem cell research successes. (The reasons for this bias are many and varied but we will not deal with them here.) As a consequence, many Americans are woefully unaware that the best opportunity to obtain regenerative medical treatments in the soonest possible time is most likely with adult stem cell therapies, not therapeutic cloning.
Here are just a few examples of the many recent exciting regenerative research successes using adult stem cells and other non-embryonic approaches:
*Brain function in five human patients with advanced Parkinson's disease was partially restored using a natural body chemical known as glial-derived neurotrophic factor (GDNF). One year after the infusion of GDNF, all patients had clinical improvement of motor function and in the ability to perform activities of daily living. Demonstrating the tremendous potential of this experimental therapy, three patients had their senses of taste and smell restored within a few weeks of starting therapy. "Phase II" human studies are now being contemplated that would include double blinding and use of placebo.
*In another Parkinson's case, a patient treated with his own brain stem cells appears to have experienced a substantial remission with no adverse side effects. Dennis Turner was expected by this time to require a wheelchair and extensive medication. Instead, he has substantially reduced his medication and rarely reports any noticeable symptoms of his Parkinson's. Human trials in this technique are due to begin soon.
*Bone marrow stem cells, blood stem cells, and immature thigh muscle cells have been used to grow new heart tissue in both animal subjects and human patients. Indeed, while it was once scientific dogma that damaged heart muscle could not regenerate, it now appears that cells taken from a patient's own body may be able to restore cardiac function. Human trials using adult stem cells have commenced in Europe and other nations. (The FDA is requiring American researchers to stick with animal studies for now to test the safety of the adult stem cell approach.)
*Harvard Medical School researchers reversed juvenile onset diabetes (type-1) in mice using "precursor cells" taken from spleens of healthy mice and injecting them into diabetic animals. The cells transformed into pancreatic islet cells. The technique will begin human trials as soon as sufficient funding is made available.
*In the United States and Canada, more than 250 human patients with type-1 diabetes were treated with pancreatic tissue (islet) transplantations taken from human cadavers. Eighty percent of those who completed the treatment protocol have achieved insulin independence for over a year. (Good results have been previously achieved with pancreas transplantation, but the new approach may be much safer than a whole organ transplant.)
*Blindness is one symptom of diabetes. Now, human umbilical cord blood stem cells have been injected into the eyes of mice and led to the growth of new human blood vessels. Researchers hope that the technique will eventually provide an efficacious treatment for diabetes-related blindness. Scientists also are experimenting with using cord blood stem cells to inhibit the growth of blood vessels in cancer, which could potentially lead to a viable treatment.
*Bone marrow stem cells have partially helped regenerate muscle tissue in mice with muscular dystrophy. Much more research is needed before final conclusions can be drawn and human studies commenced. But it now appears that adult stem cells may well provide future treatments for neuromuscular diseases.
*Severed spinal cords in rats were regenerated using gene therapy to prevent the growth of scar tissue that inhibits nerve regeneration. The rats recovered the ability to walk within weeks of receiving the treatments. The next step will be to try the technique with monkeys. If that succeeds, human trials would follow.
*In one case reported from Japan, an advanced pancreatic cancer patient injected with bone marrow stem cells experienced an 80 percent reduction in tumor size.
I COULD GO ON like this for many pages. But you get the picture. Adult stem cell and other experimental regenerative treatments are moving forward toward eventual clinical use at a breathtaking pace. Meanwhile, therapeutic cloning offers no immediate prospects for treating human ailments. If this trend continues, the day will soon come when people realize that the great hope for regenerative medicine does not come from human cloning. The question is whether or not this good news will be reported.
Wesley J. Smith is a senior fellow at the Discovery Institute. His current book is "Forced Exit: The Slippery Slope from Assisted Suicide to Legalized Murder."