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If fetal cells are as medically useful as some doctors think, we could soon have a bull market in abortion-for-profit. And that's only one of the ethical problems.
Not long ago, brain transplants seemed the stuff of cheap science fiction. The scientific consensus has long been that once a brain begins to go, there is no restoring it, that the billions of cells the brain has at birth gradually die off through life and are not replaced, regardless of whether one killed the cells through drinking, boxing, or simply growing older.
But it now appears possible that, for victims of Parkinson’s, Alzheimer’s, and other brain diseases, fresh cells grafted into the brain can stimulate functions once thought lost. Cells taken from fetuses are preferred for such grafts for two major reasons: they proliferate, and they are less likely to be rejected by the cell recipient.
Fetal transplants could herald a new age in medicine, with benefits to victims of Huntington’s disease, amyotrophic lateral sclerosis (Lou Gehrig’s disease), Alzheimer’s disease, strokes, blindness, and traumatic brain injury. They could also usher in a Brave New World. According to ethicist Arthur Caplan of the Hastings Center outside New York: "The use of fetuses as organ and tissue donors is a ticking time bomb of bioethics."
Soon, that bomb may go off. In 1988, the Department of Health and Human Services (HHS) banned government funding of experimentation on transplants of human fetal tissue. But late last year, the House of Representatives passed legislation that would lift the ban. In early April, the Senate did likewise by a veto-proof majority. The House may give the final version that comes out of the conference committee the two-thirds approval it needs to slide past the President. George Bush has said he will veto such legislation, but both bills include other funding the President would be loath to reject.
Cell Transplants for Brain Disease
Parkinson’s disease, thought to afflict as many as a million Americans, most of them over 60, is characterized by tremors and lack of muscular control. While we have no precise functional explanation for it, it results from progressive loss of nerve cells that produce the neurotransmitter dopamine in the midbrain’s substantia nigra. The normal treatment is to give Parkinson’s patients levadopa (L-dopa), which supplements reduced dopamine levels. The effect is dramatic but temporary, lasting perhaps a few years.
One alternative is the implantation of dopamine-producing tissue into the brain as a "pump." Since the central part of the adrenal glands – the medulla – produces dopamine, scientists have tried to implant adrenal "autografts" (meaning from the same person) into the caudate nucleus. Early autograft experimentation with both rats and humans proved unsuccessful in restoring normal functions.
For example, in 1986 a team led by Dr. Rene Druck-Colin of the Universidad Nacional Autonoma de Mexico autografted adrenal cells into patients’ brains, claiming at first a miraculous effect. All twenty subjects showed dramatic improvement in the course of weeks, and many returned almost to normal. But since then, approximately 180 Parkinson’s patients in the United States and Canada were given the adrenal implants, yet they experienced only modest benefits.
Researchers thus looked at fetal tissue. Human fetal tissue transplants have been tried for diabetes, severe combined immunodeficiency, DiGeorge’s syndrome, aplastic anemia, leukemia, thalassemia, Fabry’s disease, and Gaucher’s disease. They have had modest success with immuno-deficiency disorders – achieving restoration of immune function and long-term patient survival – but failed elsewhere. For example, by the end of 1989, cultured fetal pancreas cells had been transplanted in more than a hundred insulin-dependent diabetics, with the best case having been the survival of transplanted fetal pancreas tissue for thirteen weeks.
According to the Council on Scientific Affairs of the American Medical Association, there have been at least a hundred attempts to engraft fetal tissue to treat aplastic anemia, and thirty-nine attempts to use human fetal implants for leukemia, but the technique has not been feasible without recourse to severe immunosuppressant drugs and radiation.
It is as a treatment for Parkinson’s disease that fetal cell transplants have received the most attention. In early 1990, eleven Swedish researchers reported some success transplanting fetal nerve tissue into the brain of a man with severe Parkinson’s disease. "The improvement clearly has been of value to him," said Olle Lindvall, chief author of the Swedish report, to a Science reporter. The Lindvall group said it had given the fetal grafts to three other patients, but that none had been monitored long enough to determine whether the grafts were successful. The Swedish report followed on the heels of transplants at the Yale Medical School and the University of Colorado Health Sciences Center.
** The Fetal Research Ban**
Since 1972, fetal research has been permitted in the United States and several countries under certain conditions. The current ban stems from research proposals considered by the National Institutes of Health (NIH) in October 1987. In March 1988, under pressure from Reagan appointees, NIH ordered a moratorium on research. It summoned an advisory group, the Human Fetal Tissue Transplantation Research Panel (HFTTRP), to consider the ethical issues. The panel voted 17-4 to lift the ban. One of the three dissenters, James Bopp, general counsel for the National Right to Life Committee, charges that the "vast majority" of panel members were pre-selected by the panel’s chairman of scientific issues Kenneth Ryan, its chairman of ethical and legal issues LeRoy Walters, and others at NIH who favor fetal cell transplants. If not for the intercession of some congressmen, Bopp says, the panel would have been "completely lopsided."
Secretary of Health and Human Services Louis Sullivan rejected the panel’s recommendation, and was joined in this decision by Assistant Secretary for Health Dr. James Mason. Although the AMA’s Council of Judicial and Ethical Affairs reacted swiftly to denounce the moratorium, the administration seems firm in maintaining it.
** Abortion and Fetal Ethics**
"Unconscionable" is a term used by both sides in the fetal tissue debate. There seems to be no argument over the use of tissue obtained after a miscarriage; in such cases, the woman’s proxy consent is comparable to the consent of a parent to organ or tissue donation from her child. But the wide-scale use of miscarriages is impractical. Collection of fetuses is difficult, and whatever killed the fetus can cause any number of problems with the brain tissue.
The real debate is over elective abortions. Can a woman who has decided to kill a fetus be in a position to act in its best interests?
The HFTTRP okayed fetal research only if the use of the tissue were approved by the pregnant woman and if such use could be completely dissociated from the decision to abort. The panel proposed several insulating measures, including prevention of commercialization, periodic review, careful monitoring of scientific quality, and forbidding the pregnant woman to designate a recipient.
The panel recommended that "even the provision of preliminary information for tissue donation" not be volunteered to pregnant women, but Bopp argues that since the use of fetal tissue, if it proved successful, would be common knowledge, no information would be needed. Eleven members thought the information should be given to a woman considering abortion if she asked first. The panel asserted that, even "if there were a substantial increase in the number of abortions, it still would not follow that fetal tissue transplant research and therapy should not occur."
A widely used justification for cell transplants from abortions is that they are analogous to transplants from auto accident victims. Opponents counter that in a traffic accident, at least, someone other than the agent of death authorizes organ retrieval. Dr. Kathleen Nolan, then at the Hastings Center, wrote in the journal Transplantation Proceedings: "Without taking any position on the morality of elective abortion, one can still observe that results from this procedure are volitional in ways distinct from those caused by highway and other accidents." But ethicist John Robertson of the University of Texas replied:
The argument that the woman’s decision to abort disqualifies her from playing any role in disposition of fetal remains is unpersuasive. It overlooks her continuing interest in what happens to fetal tissue. It also mistakenly assumes that a person who disposes of cadaveric remains acts as a guardian or proxy for the deceased, who has no interests . . . in what happens to those remains. . . . It would lead either to a policy of using fetal remains without parental consent or to a total ban on fetal transplants.
Yet a woman electing to abort her fetus has abandoned her interest in what happens to fetal tissue. As then-President Reagan put it in a letter, "The use of any aborted child for these purposes raises the most profound ethical issues, especially because the person who would ordinarily authorize such use – the parent – deliberately renounces parenthood by choosing an abortion." In real life this is clearly the case: abortion clinics do not make a habit of asking patients how they wish the remains to be disposed.
** Incentive for Abortions?**
Anti-abortionists worry that fetal cell transplants will provide moral backing for abortion. As the National Right to Life News stated, "Using fetal tissue to ’help’ people will convert abortion, in many people’s minds, into a kind of neighborly gesture, and the local abortionist into Marcus Welby."
Reports have surfaced on women who considered getting pregnant to provide tissue for treatment. One young woman said on ABC’s Nightline that she would do so for the sake of her father, a Parkinson’s sufferer. Bioethicists have called such a stance ethical, and some diabetic women are said to have considered impregnation in order to produce tissue for self-treatment. This has led one proponent of fetal cell transplants to conclude that the fear "that the use of fetal tissue for transplantation . . . could become an incentive for abortion . . . appears well grounded."
Science magazine editor Daniel Koshland, Jr. disagrees: "Taking the kidney from a brain-dead victim of an automobile crash has not led scientists to encourage automobile accidents, and fetal tissue can be used without reference to the arguments surrounding induced abortion."
"A woman wants an abortion because she wants an abortion," says Robin Duke, co-chairman of the Population Crisis Committee in New York City. "A woman wants an abortion because she doesn’t feel this is the time to give birth. . . . There are myriad reasons for abortion. To produce fetal tissue for research is not one of them." But even Duke thinks there will be economic pressures on abortion clinics to procure and sell fetal tissue.
This is one of the areas that most worries transplant opponents – anti-abortion and pro-abortion alike – and proponents. Some of the latter argue that "clear legal prohibitions on buying fetal tissue" would eliminate financial incentives. The National Organ Transplant Act now makes payment of "valuable consideration" for the donation or distribution of specific fetal organs and "any subparts thereof" a federal crime, as do many states. Others, however, fear a black market.
Kidneys for transplantation from live donors in Brazil and India have been advertised for sale in Germany, and Arthur Caplan, who addressed the HFTTRP panel, has acknowledged that "poor women in nations where markets are permitted in organs and tissues might seek abortions solely for financial gain. . . . Policies aimed at maximizing the utilization of infants as donors could lead to increases in the number of elective abortions."
Tissue sales could be highly profitable. Hana Biologics, Inc. of California has estimated that the total potential market in treating diabetes and Parkinson’s disease with fetal tissue exceeds $6 billion. Although Hana is no longer in the business, it was selling insulin-producing cells at several thousand dollars per treatment. Abortion clinics gross perhaps $250 million annually from first-trimester abortions (1.4 million abortions a year at $175 each). Nonprofit fetal organ acquisition organizations now offer $25 per fetal organ. Since at least four fetal organs are being procured – the pancreas, brain, adrenal gland, and liver – abortion clinics could increase their profits tremendously.
And if the transplants proved successful, supply wouldn’t meet demand. The aforementioned Swedish team has been experiencing survival of dopamine at only one to five percent, making it likely that cells from several donors would be needed to replenish lost dopamine neurons. Assuming survival at the rate Lindvall has claimed (and critics like William Landau say that’s optimistic), only 10,280 of 500,000 Parkinson’s disease patients could expect fetal transplants, and there are at least a million people in the country with Parkinson’s. There are 300,000 victims of spinal injuries; 10,000 victims of hemophilia, muscular dystrophy, and Huntington’s disease; and 2.5 million victims of Alzheimer’s.
** Pro-Abortion, Anti-Transplant**
Although each side thinks the other obsessed with abortion, some see the issue of whether fetal transplants will lead to more abortions as irrelevant. Dr. Robert Levine of the Yale University School of Medicine, for example, told the Washington Post:
The law does not prescribe motivations for conceiving a fetus. Most of us grew up with an understanding of why one was conceived. Most commonly, it is to have a baby. When one says, "Let’s have a fetus so we can get substantia nigra after we abort it," that somehow strikes us as alien. [But] by what grounds can we say it is wrong? It is not illegal.
He continued: "Although the morality of abortion has always figured in the debate over the ethical permissibility of fetal research, it is notable that those who oppose the transplantation of fetal tissues seem to consider it the only issue."
In fact, some of the more outspoken foes of the procedure are ardently pro-abortion. They worry about coercion of the pregnant woman. Gena Corea, author of How American Medicine Mistreats Women, has stated, "Women will be pressured by doctors and families, or by economic need, to become fetal factories."
Janice Raymond, a professor of women’s studies and medical ethics at the University of Massachusetts, also supports the research moratorium. Raymond fears that women will be persuaded by sick family members or by promises of payment not only to have abortions but even to become pregnant in order to have one. According to Raymond,
The context in which this is [occurring] is that there is already organ trafficking and adoption trafficking and trafficking of women for prostitution and reproductive purposes. These technologies enhance that trafficking. . . . Women are now the resource for embryos, tissue, and surrogate wombs. A woman’s body has become a kind of field to be harvested. Mothers are no longer mothers, they’re intrauterine environments. Raymond distances herself from pro-lifers. "The right opposes [fetal cell transplants] because of the harvesting of fetuses, but feminists oppose it because it’s the harvesting of women."
Even the Progressive has come out against selling fetal tissue, referring to those who would do so as "flesh peddlers." The magazine was highly critical of a woman who reportedly wanted a doctor to artificially inseminate her so that she could donate fetal cells to her father, who had Alzheimer’s.
One way to determine whether fetal cell transplantation is an incentive to abort is to ask people. A substantial number say it is. Eighty percent of students surveyed in Cincinnati and El Paso answered that they thought fetal transplant surgery should be performed in the United States. Ten percent said they would approve of the selling of fetal tissue, 11 percent said they would intentionally become pregnant or get a wife pregnant to abort and donate tissue to a parent. One percent of the women said they would abort their own fetus for money, while two percent of the men supported the idea.
A poll of Glamour readers (presumably virtually all female) found that 69 percent favored the use of fetal tissue for medical research. Eight percent said they would be more likely to abort if they had an opportunity to donate fetal tissue. Four percent said women should be allowed to profit from the sale of their aborted fetuses.
** Should the Fetus Be Viable?**
There is no consensus on what age fetal cells are best to transplant; it seems to depend on the type of operation involved. Dr. Curt R. Freed, a professor of medicine and pharmacology at the University of Colorado in Denver and one of the top fetal cell transplant researchers in the U.S., reported in the Archives of Neurology (as did S.B. Blunt in the Lancet) that for Parkinsonism, cells from early gestation appear best. For humans, this would be tissue from a first-trimester fetus. Abortions performed at fourteen to sixteen weeks, the second trimester, have been standard for providing tissue used in pancreatic transplant experiments for diabetes, although it may eventually prove possible to use pancreases retrieved earlier.
Transplant opponents claim the best tissue is yielded by older fetuses and that most abortions as currently done would not be suitable for tissue collection. This bothers pro-lifers, who believe that the more developed the fetus, the more heinous the act. Feminists like Raymond worry because later abortions mean a greater chance for complications. They also fear that unsafe abortion techniques will be used with the sole intent of keeping the fetus intact.
There is clearly some truth to this last allegation. The standard type of abortion, suction aspiration, uses a vacuum cleaner-like tube with a sharp edge. The fetus is chopped into pieces only slightly larger than hamburger, making brain tissue difficult to locate. For ethical reasons, Freed said, his team would not have a woman alter her type of abortion to accommodate their research, but he also said this made their job considerably more difficult.
For purposes of conducting one experimental transplant, a medical team can afford to wade through the remains of five or ten fetuses, but certainly if transplants became common, pressure would be put on a woman to forgo suction aspiration in favor of dilation and curettage (D&C), a considerably more dangerous procedure in which the doctor uses a sharp instrument to slice the fetus up by hand and withdraw the parts.
And should the fetus be viable? This is not the standard meaning of "viability" in abortion issues, which refers to when a fetus is mature enough to survive outside the womb. Viability in this sense means whether the fetus is biologically alive. The adult human brain, when deprived of oxygen, begins to decay in a matter of minutes. It appears that fetal cells last substantially longer. Further, the cells can be quickly frozen and thawed for later use.
Nevertheless, if live fetuses must be used, that is something that some proponents of fetal cell transplants would find tolerable. Writing in the Hastings Center Report, three of them stated, "We believe . . . that use of essential organs or tissue from nonviable fetuses is morally defensible if dead fetuses are not available or are not conducive to successful transplants." They grant that pulling the brains out of live fetuses could prove painful, but say this "may be satisfactorily addressed on a practical level by using anesthesia."
** The German Experience**
Opponents of fetal cell transplantation sometimes liken it to the use of Holocaust victims’ bodies. They cite an incident investigated by the late Dr. Leo Alexander for the Nuremberg tribunal involving Professor Julius Hallervorden, who was shipped 600 preserved brains of "mercy death" victims for his research in neuropathology. Interviewed by Alexander, the doctor explained that he hadn’t authorized the victims’ murder and that it would have been a pity to waste "wonderful material" of incalculable benefit to science. Dr. August Hirt felt similarly: "These condemned men will at least make themselves useful. Wouldn’t it be ridiculous to execute them and send their bodies to the crematory oven without giving them an opportunity to contribute to the progress of society?"
According to John Robertson, the Nazi analogy is inapposite. "The Nazi experiments that were so revolting were carried out on live patients and clearly harmed them. No doctors were convicted at Nuremberg war trials for making use of cadaveric remains from the unethical experiments carried out by other physicians." Not convicted, perhaps, but it is widely held that it was immoral to make use of the bodies, and that a lack of a strong connection between those who did the executing and those who might benefit from it is irrelevant. In 1988, eighteen staff members at the Environmental Protection Agency called for a halt in the application of Nazi research data from experiments with phosgene gas on prisoners of war. Their misgiving was that "to use such data debases us all as a society, gives such experiments legitimacy, and implicitly encourages others, perhaps in less exacting societies, to perform unethical human experiments."
** Do the Transplants Work?**
Then there are those like Dr. William Landau, head of the Department of Neurology at Washington University in St. Louis, who thinks that the talk about ethics is all quite superfluous for one reason: the public perception that fetal cell transplantation is a proven, if experimental, technology isn’t true. "This is absolute science fiction," says Landau. "There’s no evidence that the brain can be transplanted functionally in an animal and it will work. The brain is a unique organ that doesn’t regenerate new cells and this isn’t going to be changed by anybody."
Some of what lies behind this perception appears to be advocacy. Even science journals have given in to boosterism. Science stated in a 1990 news article: "The results of such surgery are undeniably dramatic: Patients whose movements have been impaired for decades by the disorder have been returned to near normal functioning by dopamine-secreting tissues transplanted directly into their brains. And yet, the method has been politically and ethically sensitive."
Contrast that with the subtitle of an editorial in the August 1990 British Medical Journal: "More Patients Have Probably Been Harmed Than Helped, So Far," or the 1988 Science News article, "Fetal Cell Transplants Show Few Benefits." The very printing of the Lindvall study may reflect Science’s advocacy. Says Dartmouth Associate Professor of Neurology Richard Harbaugh, "I think if you went back through thirty years of Science and tried to find another single patient case report, unblinded and uncontrolled, you couldn’t do it. For something like this to be in Science is unheard of."
The hype may also have a political bent. In order to circumvent the FDA’s ban on the French abortifacient RU-486, abortion activists have readily grabbed at whispers of evidence that the drug "may" have properties that "may" make it effective against AIDS, cancer, and other diseases. Those arguing for less destruction of the Brazilian rain forests are now advertising that among the unknown plants therein "may" be a cure for AIDS and cancer. In the broadest sense of the word "may," these assertions "may" prove correct. But they do not reflect scientific trial and error so much as the reality that for every disease you claim you "may" have a cure for, you pull in a constituency.
Landau has no doubt that the temptation to exaggerate has been succumbed to. He says he has no ethical problems with using aborted fetuses for either experimentation or therapy – the real ethical problem is chopping holes in the brains of people who are not terminally ill when adequate animal studies have not even been performed.
Writing in the May 1990 issue of Neurology, Landau said, "This is not just an issue of bent statistics. Rather, it is one of lost scientific principles."
Landau, who has researched Parkinsonism for thirty years, is well aware of the pressures on researchers to produce positive results. He accuses no fetal cell researchers of trying to deceive anyone – other than perhaps themselves. He says that researchers are not following basic scientific procedures, and believes that Parkinson’s patients benefit simply from surgical damage in the brain that is made in the course of transplants:
There’s no evidence that the transplant experiments in animals or man show anything other than the benefits of these cuts. . . . It’s my belief, based on my knowledge of biology, that it won’t work. The likelihood that tissue will make a functional connection with the way other cells work is improbable. The circuitry of the brain is complex. It’s not like putting a piece of liver into another liver. There are different types of tissue in the brain. I can’t conceive of how infantile brain cells stuck in an adult brain will make proper connections.
On May 10, the Los Angeles Times ran an editorial entitled "More Proof, Though None Is Needed," urging President Bush to lift the fetal transplant ban. It based its argument on two studies released a few days earlier at a San Diego convention updating the fetal cell transplant experiments in Colorado and at Yale.
The editorial reported that some of the patients given cells had improved, without noting that the control patients in the Yale study – those who had not received fetal cells – had also improved, a result that calls into question the effectiveness of fetal cell transplants. It also neglected to mention a study headed up by New York University neurosurgeon Michael Dogali, in which patients with Parkinsonism who had small pieces of their brains removed showed significant improvement.
One researcher on the experiment, neurologist Enrico Fazzini, said that outcome perhaps indicated that the improvement noted in the Denver and Yale patients was caused not by fetal cells but by the cuts themselves, as Landau has hypothesized. It seems that despite its claims to the contrary, the L.A. Times will need more proof.
Landau says that one means by which fetal cell transplants could conceivably work would be by acting as a pump, as with diabetes patients. "But the cells injected have to be able to react to blood sugar the way normal cells do," and this could be problematic. "On the other hand, maybe they wouldn’t regulate but could serve as reservoir. But then why not just put a slow-leaking bottle of levadopa into the brain?" (In fact, pocket-sized insulin pumps for diabetics will soon be in general use.) "The irreversible tragedy is the death and damage to many patients and their families produced by the extravagance of the transplantation fad," he said.
At the 1989 annual meeting of the American Association of Neurological Surgeons in Washington, D.C., as the _Journal of the American Medical Association (JAMA) _put it, "The consensus [was] that while [grafting] is still promising, particularly when fetal brain tissue is grafted, new side effects are continuing to emerge." Specifically noted was the breaking of the blood-brain barrier that persisted for several months after surgery in six patients. Such breaches can prove fatal.
** Rejected Tissue**
In general, fetal neural cells are less likely to cause rejection than adult tissue from another person. They often fail to cause significant immune responses when implanted in rodents and apes, and have been used in successful human operations without immune suppression. However, animal studies comparing the immunogenicity of fetal pancreas with adult pancreas cells show that the fetal tissue can be as immune-incompatible, if not more so, than adult tissue. Fetal liver cells have also prompted immune responses.
Researcher George Allen, of the Vanderbilt University Medical School, head of the most experienced American group in brain graft therapy, says: "Putting aside the practical and ethical problems of getting donor tissue . . . there is the issue of graft rejection. We’ve seen signs of rejection in some experimental animals, and we don’t know what this would mean in functional terms in humans. Presumably, long-term immunosuppression would be necessary." He adds: "We don’t know what fetal tissue would do over a period of many years. There’s a possibility it could grow and become an invasive tumor."
"Why," asks Father Robert Barry, a bioethicist at the University of Illinois, "should these patients be put into a life-threatening condition in order to alleviate one that is only debilitating?"
Nevertheless, many doctors remain convinced of the potential of fetal cells. Druck-Colin says, "There is no question that the patients get better. The real question is: For how long will they get better?" Freed says the improvements shown by his first successful patient, recounted in the May 1990 Archives of Neurology, went far beyond those expected from the surgical cuts. Freed has now operated on seven patients, claiming some success with four of them. He rejects Landau’s hypothesis that it isn’t the fetal cells but some other aspect of the operation that causes a lessening of the symptoms. "In animals, particularly the rat," he says, "it’s well worked out. The dopamine cells actually grow . . . kind of like seeds and roots. These supply the adult brain with connections. It’s actually a replacement cell for dead adult brain cells.
"People are trying to explain minor degrees of improvement in adrenal autografts. With fetal cell transplants we’ve found the less injury the better, so we think that doesn’t account for effectiveness of fetal cell transplants."
Transplant opponents argue that there is no reason to portray providing therapy for Parkinson’s disease patients or patients of other diseases as an either-or situation: either fetal cell transplants will help them or nothing will. Indeed, they say, all this fuss is a distraction from therapies that may prove cheaper, less painful, and more permanent, with the bonus that they completely bypass the touchy ethical issues. There are many alternative therapies either just around the corner or already being tried out.
It is difficult to predict developments for Parkinson’s and other brain disorders because pharmaceutical and biotechnical companies guard their research very closely, and because the hype that has pervaded the fetal cell transplant area is common to all research science. But one drug recently put into use, Deprenyl, substantially slows the rate of neurodegeneration in Parkinsonian patients, according to a Science article by neurologists James Tetrud and William Langston. Deprenyl inhibits monoamine oxidase, a substance present in many different body cells and one that breaks down dopamine. "The magnitude of the effect is much greater than we could have hoped for," says Langston. "I suspect that very soon Deprenyl will find a place in the early treatment of Parkinson’s disease." Again, Landau is skeptical.
Nerve growth factor (NGF) is a promising chemical for Alzheimer’s. NGF is a key protein in the development and repair of the peripheral and central nervous systems. Injected into the brains of aged rats with a lower than normal ability to learn to swim a water maze, NGF improved their learning behavior and partly reversed the atrophy of the cholinergic (acetylcho- line-secreting) neurons seen in the aged animals. According to one researcher, Dr. Fred Gage of the University of California, San Diego, "People are not saying that it’s a cure, or that it treats the cause, but it may treat one of the symptoms." No one expects the growth factor to restore connections that are already lost – the goal is to stave off further deterioration.
Yet Anders Bjorklund of the University of Lund, in Sweden, reported in the British journal Nature that he had actually reversed memory deficiency in rats, which he says is similar to Alzheimer’s in humans, by injecting them with something different – epidermal growth factor. While the application is only by analogy, other scientists consider Bjorkland’s experiment a step toward correcting the chemical upsets that may underlie chemical loss and toward treatments that have nothing to do with transplants. "The potential," says Don Marshall Gash, professor of neurobiology and anatomy at the University of Rochester, "is that ultimately we might need only to transfer chemicals, not entire cells, an obviously simpler procedure."
For decades, scientists have sought drugs that could penetrate the blood-brain barrier, and are beginning to make great strides. Researchers in Alabama have developed a substance that would allow dopamine to be conveyed with great precision to specific parts of the brain. Some of the more advanced work has been done by Nicholas S. Bodor, vice president for research at Pharmatec and a research professor at the University of Florida. Taking advantage of the capillary walls’ affinity for fatty molecules, Bodor’s technique combines a common fat-soluble carrier molecule with a drug molecule that it carries across the blood-brain barrier. Once there, the drug molecule is trapped, while the carrier molecule is expelled through the blood-brain barrier back into the capillaries.
"I suspect," says Richard Jed Wyatt, a transplant pioneer from the National Institute of Mental Health (NIMH), "that we will gradually identify a slew of previously unknown substances in the brain as important to maintaining health as insulin is in diabetes."
In the March 27 issue of Science, two scientists reported their discovery that mouse brain tissue, when stimulated by NGF in a laboratory dish, has the capacity to produce new nerve cells. This discovery challenges the traditional view that the brain cells of post-natal mammals cannot regenerate. The scientists have yet to try to reproduce these results in living mice, but – considering that the cells in question are from the same part of the brain affected by Parkinson’s, Huntington’s, and other diseases; that a transplant would come from the person himself, thus negating the possibility of rejection; and that the cells would be adult ones – the ramifications would be tremendous.
This report was followed by one in the May 8 issue of Science, describing an almost complete reversal of Parkinsonism symptoms that had been induced in monkeys. The monkeys were injected with a substance derived from cow brains. Whether it will work in humans with actual Parkinson’s disease remains to be seen, but the substance has already been used on humans with spinal cord injuries, with significant improvement shown.
However effective fetal cell transplantation turns out to be, it could well be surpassed by other technology before it comes to fruition, rather like the astronaut in the Twilight Zone television series who returns from a forty-year round-trip visit to a distant planet only to find that he has wasted half his life because faster ships have been developed since he left and have beaten him back to earth. At worst, fetal cell transplants may be the equivalent of the Jarvik-7 – little more than an instrument of torture for the brave souls who assume guinea pig status for it. Given the lack of good animal data, the scarcity of medical research funds in general, and not least of all the repugnancy that much of society has toward using human tissue that was not consensually given, Congress would be advised to turn its attention to matters more pressing than lifting the ban on fetal tissue research.