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    China’s gene-spliced pigs are helping cure humans
    China’s gene-spliced pigs are helping cure humans
    SCIENCE

    China’s gene-spliced pigs are helping cure humans

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    by
    Xinyan Yu
    Xinyan Yu
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    Meet Lai Liangxue: scientist and pig hotelier.

    His job involves pampering some 500 pigs every day at his “pig hotel” on the outskirts of the southern Chinese city of Guangzhou.

    The pig hotel is “a monitored farm breeding pigs with edited genes,” Lai explains. These special pigs are responsible for helping Lai and his team at the South China Institute of Stem Cells and Regeneration Medicine to find cures for human diseases.

    “We modify their genes so that they catch human diseases and we can work on how to cure them,” he tells Inkstone. 

    Staff at the ‘pig hotel’ in Guangzhou.
    Staff at the ‘pig hotel’ in Guangzhou. Photo: Guangzhou Institute of Biomedicine and Health, China Academy of Sciences
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    Using animals to test drugs for humans is common practice for scientists all around the world, but Lai’s team has big ambitions.

    They have successfully used gene-editing techniques to make pigs produce human proteins such as insulin, and now they are working on growing pig organs that can be transplanted into human bodies.

    Are pigs going to save human lives?

    The latest breakthrough made by Lai’s special pigs has enabled a group of scientists to establish a pig-based model of Huntington’s disease.

    A paper on this research was published in the Cambridge-based scientific journal Cell last week.

    Like other incurable neurodegenerative diseases such as Alzheimer’s and Parkinson’s, Huntington’s disease is a fatal genetic disorder that kills brain cells and deteriorates a person’s physical and mental abilities.

    It causes involuntary movements notoriously known as “Huntington’s dance.”

    The gene-modified pigs are set to help find a cure for Huntington’s disease.
    The gene-modified pigs are set to help find a cure for Huntington’s disease. Photo: Guangzhou Institute of Biomedicine and Health, China Academy of Sciences

    Professor Xiaojiang Li and Shihua Li at the Emory University School of Medicine were the lead scientists on this project, which successfully used the CRISPR/Cas9 gene editing technique to insert a segment of a human gene causing Huntington’s into pig cells.

    “It’s a significant breakthrough because our pigs demonstrate a gradual brain cell decline that result in the ‘Huntington’s dance’ just like humans would do as they grow old,” Professor Xiaojiang Li told Inkstone.

    The team was also the first to breed pigs that carry the mutated genes through generations – a characteristic of neurodegenerative diseases.

    Although scientists have been introducing the problematic human genes into lab animals such as mice to observe how neurodegenerative diseases work, pigs are much more ideal models given the similarity between human and pig organs, blood vessels and brain sizes.

    A human’s brain is around the size of a pineapple; a pig’s brain is around the size of a bell pepper; a mouse’s brain is around the size of a blueberry.
    A human’s brain is around the size of a pineapple; a pig’s brain is around the size of a bell pepper; a mouse’s brain is around the size of a blueberry.

    Many drugs proven efficient to cure Huntington’s on mice did not have the same effect on humans, because rodent brains are much smaller and they don’t live live nearly as long as humans.

    Building a pig model of the Huntington’s disease is only a small step towards solving a bigger problem.

    These pigs will be used for testing drugs and for stem cell treatment trials. Compared to the mice model, the results of these experiments would be much more likely to work similarly on humans.

    In the long-term, scientists hope finally to find a cure for neurodegenerative diseases caused by genetic mutation.

    Is China going too far?

    In Lai’s “pig hotel”, the gene-editing technique CRISPR/Cas9 plays a key role in all experiments.

    It is a precise method of genetic manipulation that allows scientists to alter sections of an organism’s DNA sequence.

    The gene-editing technique CRISPR/Cas9, also known as the ‘gene scissors.’
    The gene-editing technique CRISPR/Cas9, also known as the ‘gene scissors.’ Photo: Guangzhou Institute of Biomedicine and Health, China Academy of Sciences

    Although the technique was invented in the USA, China has been at the forefront of its application on projects like Professor Li’s pig model of Huntington’s disease.

    But many question the ethics surrounding the gene-editing techniques being used.

    A heated debate started in 2015 with the world’s first-ever case of gene editing in human embryos. Junjiu Huang, a gene-function researcher at Sun Yat-sen University in Guangzhou who carried out the procedure, tried to mitigate concerns by using embryos that could not result in live births.

    In January, the Wall Street Journal reported on China’s controversial first human trial using CRISPR/Cas9 to treat cancer patients, sparking a new round of discussion on the ethics behind China’s scientific advances.

    Professor Xiaojiang Li (center), Lai Liangxue (second from right) and team.
    Professor Xiaojiang Li (center), Lai Liangxue (second from right) and team. Photo: Guangzhou Institute of Biomedicine and Health, China Academy of Sciences

    China’s lead in gene-editing trials is “unhampered by rules”, the Journal says. Many advocate for an international consensus on ethical issues around a science that makes fundamental changes to human DNA, yet still isn’t completely understood.

    Although gene-editing in animals is less controversial than in humans, critics have said there’s a risk of edited genes becoming “permanent” and passed on to future generations, said an article in the scientific journal Nature.

    Group 5
    It’s much more difficult to get projects using pigs and primates approved in the USA
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    Professor Xiaojiang Li, Emory University School of Medicine

    “We do have a rigorous procedure in terms of using animals for gene-editing experiments,” Professor Xiaojiang Li explains. “What’s unique about China is the majority of people acknowledge the importance of these experiments so we receive lots of support from the community.”

    Professor Li partnered with Lai’s pig farm in 2008, partially because it’s easier to conduct research in China.

    “It’s much more difficult to get projects using pigs and primates approved in the USA,” he said. “The cost of managing these projects is very high.”

    So far, many Chinese scientists prefer to keep a low profile when it comes to seeking international recognition for their research made possible with gene editing – at least until they achieve something truly groundbreaking.

    XINYAN YU
    XINYAN YU
    Xinyan is a senior multimedia producer at Inkstone based in Beijing. Previously, she was a producer at BBC News.

    XINYAN YU
    XINYAN YU
    Xinyan is a senior multimedia producer at Inkstone based in Beijing. Previously, she was a producer at BBC News.

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