Be careful putting human brain cells in animals, panel tells scientists

<body leftmargin="0" bgcolor="#000060" text="#FFFFFF" link="#FFFF00" vlink="#FF9900"> <p class="MsoNormal"> <b><font face="Arial" size="2">Scientists are grappling with a new and troubling moral issue: whether it’s right to put human brain cells in the brains of animals.<br> <br> Researchers have begun to do this as part of studies into stem cell therapies. These therapies would treat diseases by implanting people with cells capable of maturing into various different types, including brain cells. <br> <br> But no one knows whether such experiments might bestow more human-like qualities on apes or other animals, raising sticky questions. Would such creatures have human rights? Should they be created at all?<br> <br> A panel of scientists, philosophers and and lawyers has taken on the question of how far such research should be allowed to go. After deliberations that started over two years ago, the panel issued a report of its findings in the July 15 issue of the research journal Science.<br> <br> The panel declined to recommend a halt to this research, but proposed a number of step to minimize the chance of mishaps that could spawn potentially unsolvable moral quandaries.<br> <br> It’s extremely unlikely that animals with significant human-like qualities would arise from this research, the panel found, but it is possible. And the risk is “too ethically important to ignore,” it concluded, according a statement issued July 14 by Johns Hopkins Medical Institutions in Baltimore, Md. The panel did its work as part of a Johns Hopkins program.<br> <br> “Experiments implanting, or grafting, human stem cells into non-human primate brains could unintentionally shift the moral ground between humans and other primates,” said the Hopkins statement.<br> <br> The panel reported recommendations for minimizing the chances that such experiments could change the cognitive and emotional capabilities—and hence the “moral status” of the animals.<br> <br> “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, director of The Johns Hopkins University’s Berman Bioethics Institute.<br> <br> John Gearhart of Johns Hopkins’ Institute for Cell Engineering noted that such experiments are already under way. Some people see them as a necessary, he added, toward developng treatments to replace or repair brain cells lost in conditions like Parkinson’s disease or Lou Gehrig’s disease.<br> <br> In its discussions, the panel decided to set aside an older disagreement whether primates should be used at all for invasive medical research, Faden said. The members opted to “focus instead on whether experiments with stem cells and the brain posed any new, unique ethical dilemmas.” <br> <br> Most neuroscientists believe primate brains are too different structurally from human brains for a few implanted human cells to give them significantly human-like thoughts, especially if the implantation occurs during adulthood when the brain is already developed. <br> <br> But the possibility can’t be ruled out, either, they said.<br> <br> “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? <br> <br> “There are biblical injunctions and secular reflection over the course of centuries, but nothing is certain or universally accepted, either scientifically or morally,” she added. “Debate is complicated by uncertainty and uncharted territory in all of our fields of expertise. It quickly became clear how little is known.” <br> <br> “Many of us expected that, once we’d pooled our expertise, we’d be able to said why human cells would not produce significant changes in non-human brains,” said Mark Greene of 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.” <br> <br> Although unable to rule out the possibility of morally significant changes resulting from implantation of human stem cells into the non-human 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 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. <br> <br> The panel also recommends 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. <br> <br> “And, 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.” <br> <br> Faden said the panel’s work, started more than two years ago, complements a recent report on stem cell research by the National Academy of Sciences. That report called for in-depth consideration of the ethics of implantation of human stem cells into the brains of non-human primates. </font></b> </p> </body>