Scientists and ethicists are struggling with guidelines for research that is implanting, or grafting, human stem cells into non-human primate brains and which they say could shift the moral ground between humans and other primates

By Robert Duncan

In the Planet of the Ape film series an evolutionary trigger bequeaths monkeys the ability to speak - and subsequently non-human primates subjugate humans to a life of slavery. While that series is pure science fiction, there is concern that current experiments producing chimeras - creatures created from more than one biological species - of the human-ape variety create, if not an artificial evolutionary leap, at least a moral quandary.

Some scientists and pressure groups claim that the creation of chimeras is needed for medical advances. But Hank Greely, JD, a law professor at Stanford University and chair of the Stanford Center for Biomedical Ethics steering committee, suggests caution is needed. According to Greely, research in monkeys and apes raises some distinct ethical issues. "The possibility that human cells might create human-like abilities is much larger in nonhuman primates than in mice," said Greely.

It should be noted that the ethics committee that Greely chaired in January (2005) endorsed a proposal to create mice that had brains that were made almost entirely from human brain cells. That committee also recommended closely monitoring the mice - and immediately killing any that displayed human-like behavior, according to an Associated Press article.

In April 2005 a National Academies 10-member panel issued guidelines to apply to stem cell research that included a ban on introducing human stem cells into the embryos of animals, as well as prohibiting introducing human stem cells in the brains of monkeys as it could affect the primates' brain structure or mental function. Those guidelines are voluntary.

Supporters of such research argue that, at least in theory, stem cells can be separated from early human embryos, and transformed into almost any other type of cell.

"Embryonic stem cells show some therapeutic potential, though their potential thus far appears to be significantly less that the potential of the adult stem cells which are, less easily available, but pose no ethical barriers. Embryonic stem cells, however, are easily cloned from “unwanted” fertilized eggs generated during in vitro fertilization, and from abortion products. However, because human embryos must be destroyed to retrieve them, there are strict limits on federally funded stem cell research. Specifically, under current federal law, no human embryo can be destroyed to develop embryonic stem cell “lines” although scientists are permitted to use lines in existence before the 2001 date set by President Bush," according to Dr. Shari de Silva as reported in a Spero News article. "Further, chimeras would not be permitted to breed in order to prevent the creation of a hybrid with human intellectual capacities in animal form."

In the meantime, experiments continue.

Yale University's Dr. Eugene Redmond, professor of psychiatry and neurosurgery has set up a facility in the Caribbean island of St. Kitts where he is injecting "immature human brain cells" into a region of the brain of vervet monkeys that produces dopamine - a chemical that Parkinson's patients lack - as reported in the New York Times.

Such activities are cause for concern.

A 22-member panel of stem cell scientists, primatologists, philosophers and lawyers recently concluded that experiments implanting, or grafting, human stem cells into non-human primate brains could unintentionally shift the moral ground between humans and other primates.

Writing in the July 15, 2005 issue of Science, the panel reported its recommendations for minimizing the chances that experiments with human stem cells could change the cognitive and emotional capabilities -- and hence the "moral status" -- of the animals. The panel's work was part of the Program for Cell Engineering, Ethics and Public Policy of the Berman Bioethics Institute and the Institute for Cell Engineering at Johns Hopkins.

Before conducting research that involves putting human stem cells into the brains of nonhuman primates, scientists and oversight committees should consider a series of ethical criteria, the panel said.

"We quickly realized that a fundamental issue was whether such experiments might unintentionally alter the animals' normal cognitive capacity in ways that could cause considerable suffering," said Ruth Faden, Ph.D., M.P.H., director of the Phoebe R. Berman Bioethics Institute at The Johns Hopkins University.

Faden, John Gearhart, Ph.D., of Johns Hopkins' Institute for Cell Engineering, and Guy McKhann, M.D., of Hopkins' Zanvyl Krieger Mind/Brain Institute, were co-organizers of the panel.

The panel's deliberations focused on the potential effects of grafting human stem cells into the brains of non-human primates. Gearhart acknowledged that such experiments are already under way and that some people see them as a necessary step toward using human stem cells as treatments to replace or repair brain cells lost in conditions like Parkinson's disease or Lou Gehrig's disease.

Stanford's Greely suggested that if a large number of human cells were to be injected into a part of the brain where those cells may be involved in thinking or emotions, that experiment may not be ethical. But injecting a smaller number of cells into a region of the brain that controls movement may be acceptable.

"People need to think responsibly about how to minimize ethical risks these sorts of experiments might entail," Greely said.

Greely said his colleagues found no ethical reason for prohibiting research involving human stem cells in nonhuman primate brains.

This type of work may even be required by the U.S. Food and Drug Administration to show that a potential therapy involving human stem cells is effective, he said.

However, not all scientists would agree with his statement.

Faden said, "We agreed to disagree about whether non-human primates should be used for invasive biomedical procedures at all, and to focus instead on whether experiments with stem cells and the brain posed any new, unique ethical dilemmas."

Although the experts agreed it was unlikely that grafting human stem cells into the brains of non-human primates would alter the animals' abilities in morally relevant ways, they also felt strongly that the risk of doing so is real and too ethically important to ignore.

"Our group struggled with many fundamental questions," said Faden. "Are there cognitive or emotional capacities that are unique to humans in ways that make us worthy of higher moral status? What sets one primate, including us, apart from another primate, cognitively speaking?"

"There are biblical injunctions and secular reflection over the course of centuries, but nothing is certain or universally accepted, either scientifically or morally," Faden added. "Debate is complicated by uncertainty and uncharted territory in all of our fields of expertise. It quickly became clear how little is known."

"Many of us expected that, once we'd pooled our expertise, we'd be able to say why human cells would not produce significant changes in non-human brains," said Mark Greene, Ph.D., then a Greenwall Fellow at Hopkins and now a professor at the University of Delaware. "But the cell biologists and neurologists couldn't specify limits on what implanted human cells might do, and the primatologists explained that gaps in our knowledge of normal non-human primate abilities make it difficult to detect changes. And there's no philosophical consensus on the moral significance of changes in abilities if we could detect them."

Although unable to rule out the possibility of morally significant changes resulting from implantation of human stem cells into the non-human primate brain, this latest panel concluded that cognitive and emotional changes are least likely to occur when such work is conducted on healthy adult members of species distantly related to humans, such as macaques, rather than early in the brain development of our closest biological relatives, the chimpanzees and other great apes.

"To fill in the gaps in our knowledge, proposed studies should measure and monitor behavioral, emotional and cognitive changes," said Faden. "We need to know whether the human cells have an effect on cognition, but right now, the experts aren't even quite sure what 'normal' is for some of these primates. These studies should have a component to look into that question."

Faden said the panel's work, started more than two years ago, complements the April report on stem cell research by the National Academy of Sciences. The NAS report called for in-depth consideration of the ethics of implantation of human stem cells into the brains of non-human primates.

The panel also recommended that specific ethical oversight be applied to studies that propose grafting human stem cells or cells derived from human stem cells into the brains of other primates.

However, the group found that oversight boards at universities or funding agencies should consider six factors when overseeing such research:

1) the number of human cells used compared with the number of cells in the animal's brain,

2) the developmental stage of the animal receiving the cells (i.e. fetus or adult),

3) the species,

4) the animal's brain size,

5) the site where the stem cells are placed and

6) whether the animal's brain was injured or diseased.

Some information provided by Stanford University Medical Center and John Hopkins Medical Institutions

Originally written in 2005 for various publications

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Robert Duncan is a journalist and ombudsman for foreign press in Spain. He is an Executive Board Member and Vice-President for the Organización de Periodismo y Comunicación Ibero-Americana, and Vice-President of the energy and telecommunications association, APSCE. He is News Editor for Spero News, and Editor-In-Chief of EnerPub and Santificarnos.

He has also been published in World Catholic News, National Catholic Register, Renew America, Lifesite.net, as well as Capital Hill Coffee House, Common Conservative, The Conservative Voice, Enter Stage Right, News By Us, Conservative Crusader, World Net Daily, Mens News Daily and others. Robert was the bureau chief for an international news agency in Madrid for many years, and was published regularly in Dow Jones Newswires, with articles appearing in The Wall Street Journal.