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Prof discusses issues in stem cell research
Mark Greene, assistant professor of philosophy, wrote in the journal’s Policy Forum section that an expert panel of stem cell scientists, primatologists, philosophers and lawyers organized by the Program for Cell Engineering, Ethics and Public Policy at the Phoebe R. Berman Bioethics Institute at Johns Hopkins University has concluded that experiments grafting human stem cells into nonhuman primate brains could unintentionally shift the moral ground between humans and other primates. The article also reports the panel’s 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. Greene, who was a Greenwall Fellow at Johns Hopkins before joining the UD faculty, said the panel’s findings were unforeseen. “Going into this, I expected, and I think most of us did, that the possibility of this work making any morally significant difference to recipients of human neural cells was pretty far-fetched,” he said. “But, as the discussion progressed, it emerged that there really is no good basis to be quite so comfortable.” Greene said that too little is currently known about the normal cognitive abilities of nonhuman primates and about the capacities of stem cells. “This,” he said, “creates an ethically important uncertainty.” Neither the cell biologists nor the neurologists on the panel could specify limits on what implanted human cells might do, Greene said, and the primatologists explained that gaps in knowledge concerning normal nonhuman primates’ abilities make it difficult to detect changes. Furthermore, he said, there was no philosophical consensus on the moral significance of changes if, indeed, changes could be detected. Though unable to rule out the possibility of morally significant changes resulting from implantation of human stem cells into the nonhuman primate brain, the panel concluded that cognitive and emotional changes are least likely to occur when such work is conducted on healthy adult members of distantly related primate species, such as macaques, rather than early in the brain development of our closest biological relatives, the chimpanzees and other great apes. The panel 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. “If one thing comes out of this, I hope it is that researchers will look for cognitive effects as this kind of work goes forward,” Greene said. “We need to gather the information that will enable us to make scientifically and ethically informed decisions about this work in the future.” Interest in this particular subject was driven by the fact that this type of research is beginning to happen, Greene said. A recent National Academy of Sciences report on stem cell research calls for in-depth consideration of the ethics of implantation of human stem cells into the brains of nonhuman primates, and National Research Council guidelines on stem cell research raise the specific issue of interspecies neural grafting. The Program for Cell Engineering, Ethics and Public Policy at the Phoebe R. Berman Bioethics Institute is headed by Ruth Faden. The program conceives of ethics and policy projects, with this particular project funded by the Greenwall Foundation. Greene joined the UD faculty in 2003, after completing a postdoctoral fellowship with the program at Johns Hopkins University. Article by Neil Thomas To learn how to subscribe to UDaily, click here. |
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