Neurologists may have undergone an "ethical rubicon" by raising lumps of human brain in the laboratory and in some cases transplanting animal tissue, researchers warn.
The creation of mini-brains or brain "organoids" has become one of the hottest areas in modern neuroscience. The tissue spots are made from stem cells and, although they are only pea-sized, some have developed spontaneous brain waves similar to those seen in premature infants.
Many scientists believe that organoids have the potential to transform medicine by allowing them to examine the living brain as never before. But the work is controversial, since it is unclear where the line can go in experiments with humans.
On Monday, researchers will tell the largest annual meeting of neurologists in the world that some scientists working on organoids are "dangerously close" to crossing the ethical line, while others may have done so by creating conscious lumps brain in the lab.
"If the organoid could even be alive, we could cross that line," says Elan Ohion, director of the Green Neuroscience Laboratory in San Diego, California. "We don't want people to do research where there is the potential to suffer something."
Due to the obvious difficulty in studying living human brains, organoids are considered a remarkable development. They have been used to study schizophrenia and autism and why some babies develop cerebellum when infected with the Zika virus in the womb. The researchers hope to use organoids to investigate a range of brain disorders ̵
But in their presentation at the meeting of the Neuroscience Society in Chicago, Ochion and his colleagues Ann Lam and Paul Tsang will state that there must be checks to ensure that brain organoids do not suffer. "We are already observing organoid activity, which is reminiscent of biological activity in developing animals," Ohayon says.
In a recent study, Harvard researchers showed that brain organoids develop a wide variety of tissues – from brain cortex neurons to retinal cells. Organoids, grown for eight months, developed their own neural networks, which sparkled with activity and reacted when their light shone. In another study led by Fred Gage of the Salk Institute in San Diego, researchers transplanted human brain organoids into the brains of mice and found that they were related to the animal's blood supply and had germinated fresh connections.
Ohayon wants funding agencies to freeze all research that aims to put human brain organoids in animals, along with other work that has a reasonable chance of organoids being felt. Ohayon has developed computer models that, he says, help identify when reason is likely to arise, but adds that there is an "urgent need" for more work in the area.
In the UK, researchers are now prohibited from working on donated embryos that are more than 14 days old. The restriction that some scholars want to expand has been imposed to protect developing people from suffering.
Last year, a group of scientists, lawyers, ethics and philosophers called for an ethical debate on brain organoids. The authors, including Hank Greeley, director of the Stanford University Center for Law and Biological Sciences at the University of California, said the organoids are not yet complex enough to cause immediate concern, but it's time to start discussing the guidelines.
Greeley said there was no ethical line as far as organoids were concerned. "I'm sure they don't think we've reached the state of Gregor Samsa, where one wakes up and finds himself organoid," he said, referring to the character in Franz Kafka's Metamorphosis, which he wakes to find is a giant insect. But he added, "If they mean the potential to perceive or respond to things, that seems likely to me."
Grillie believes that anxiety becomes more serious if organoids perceive and respond to stimuli that can cause pain. "This is all the more important if we have reason to believe that the organoid has a disgusting response to these stimuli, that it 'feels pain'. I highly doubt anyone has reached this point or come close to it, "he added.
Gage told the Guardian: "I think it is never too early to raise questions about ethics in science so that a meaningful dialogue can guide research and decisions. “