{"id":769335,"date":"2022-08-04T06:47:48","date_gmt":"2022-08-04T10:47:48","guid":{"rendered":"http:\/\/animalrightswatch.us\/?p=769335"},"modified":"2022-08-04T07:57:39","modified_gmt":"2022-08-04T11:57:39","slug":"hybrid-brains-the-ethics-of-transplanting-human-neurons-into-animals","status":"publish","type":"post","link":"http:\/\/animalrightswatch.us\/?p=769335","title":{"rendered":"BRAIN TEASERS: The unethical and cruel experiments of transplanting human neurons into animals"},"content":{"rendered":"\t
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Some scientists warn that such chimaeras represent an ethical grey zone, because of the potential to blur the line between humans and other animals, or to recapitulate human-like perception or cognition in an animal.<\/p>\n\t\t<\/div>\n\t\t\t<\/blockquote>\n\n

KENDALL POWELL:<\/strong> In a darkened room in a laboratory in London, a group of students and researchers watch a clump of human brain cells settle into their new home: a living mouse brain. On a computer monitor next to a microscope, the human cells light up in flashes of simultaneous activity. Over time, the cells sprout new connections a few centimetres long, and form networks with each other. It\u2019s captivating viewing for his students, says Vincenzo De Paola, who runs the lab at Imperial College London. \u201cIt\u2019s all they want to do. I can\u2019t tear them away,\u201d he says…<\/em><\/p>\n

De Paola\u2019s group is one of just a handful of labs able to study human neural cells at work in a live, developing brain \u2014 a system that is otherwise largely off limits for both ethical and technical reasons. \u201cWe cannot study these processes as they unfold in a fetal human brain,\u201d he says. \u201cInstead, we wanted to watch human cortical neurons mature and form active networks in a live animal.\u201d<\/em><\/p>\n

De Paola\u2019s system is a specialized type of neural chimaera \u2014 an area of research that has expanded immensely in the past five years, sparking a debate about the ethics of blending human and animal brain tissue. Proponents say that such systems are necessary to manipulate live human neurons and are already yielding important insights into health and disease. For example, using neural chimaeras, scientists have found differences in how neurons develop and behave in Down\u2019s syndrome and Alzheimer\u2019s disease.<\/em><\/p>\n

But others warn that such chimaeras represent an ethical grey zone, because of the potential to blur the line between humans and other animals, or to recapitulate human-like perception or cognition in an animal. Some researchers say these kinds of chimaeras should only be used if no other cell or animal model is appropriate. \u201cIs this a really good model for answering a scientific question or are we pushing boundaries for the sake of it?\u201d asks Naomi Moris, a developmental biologist at the Francis Crick Institute in London. Ethicists are asking at what point a collection of human neurons in another animal\u2019s brain embodies something that deserves a unique moral status…<\/em><\/p>\n

Researchers are starting to consider going beyond transplanting a few isolated cells to creating chimeric animals with human brain regions. Studies that transplanted human brain stem cells into monkeys\u2019 brains helped to launch a 2018 clinical trial testing whether human brain stem-cell transplants can treat Parkinson\u2019s disease. In 2019, Japan reversed a ban on government funding for research using human\u2013animal chimeric embryos. In many countries, including the United States and the United Kingdom, research that mixes human brain cells or tissue with another animal\u2019s brain is legally allowed, and can be government-funded with an extra layer of review. The United States prohibits government funding for human\u2013animal chimeric embryo research…<\/em><\/p>\n

\u201cThe neural combinations touch on what it is that makes us essentially humans \u2014 our minds, our memories, our sense of self,\u201d says Alta Charo, a bioethicist based in Washington DC and professor emerita at the University of Wisconsin-Madison. The public, she says, finds the idea of a human mind trapped in an animal\u2019s body, or a creature with a semi-human brain, disturbing.<\/em><\/p>\n

She and other ethicists think there is a large gap in the public\u2019s understanding of why this research is being undertaken. Neural-chimaera researchers should be sharing their work with the public more often, she says… \u00a0As research progresses, Charo notes that researchers will have to consider what proportion of human brain tissue might begin to approach cognition in a dish or evoke human characteristics in a mouse \u2014 and when that might add emotional distress or pain for the animal. <\/em>SOURCE…<\/em><\/strong><\/a><\/p>\n

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