Evening Telegraph (First Edition)
Pig-to-human organ transplant advance
GROWING human transplant organs in pigs has become a more realistic prospect after scientists used gene editing to remove viruses from the animals’ DNA.
Porcine endogenous retroviruses (Pervs) are permanently embedded in the pig genome but research has shown they can infect human cells, posing a potential hazard.
The existence of Pervs has been a major stumbling block preventing the development of genetically engineered pigs to provide kidneys and other organs for transplant into human patients — a process known as xenotransplantation.
That hurdle may now have been cleared away, according to new research reported in the journal Science.
Researchers in the US used the precision gene editing tool Crispr-Cas9 combined with gene repair technology to deactivate 100% of Pervs in a line of pig cells.
Piglets cloned from the fibroblast (connective tissue) cells turned out to be Perv-free.
Dr Luhan Yang, co-founder and chief scientific officer at the biotech company eGenesis, said: “This is the first publication to report on Perv-free pig production.
“We generated a protocol to enable multiplex genome editing, eradicated all Perv activity using Crispr technology in cloneable primary porcine fibroblasts and successfully produced Perv-free piglets.
“This research represents an important advance i n addressing safety concerns about cross-species viral transmission.
“Our team will further engineer the Perv-free pig strain to deliver safe and effective xenotransplantation.”
The scientists first mapped the Pervs present in the pig genome, identifying 25 in total.
Tests demonstrated that pig cells could infect human cells with Pervs in the laboratory. The viruses could then be transmitted to other cells not exposed to pig tissue.
Whether or not Pervs would actually cause diseases in humans is unknown, but they are considered an unacceptable risk.
Other endogenous retroviruses in humans have been suggested to play a role in cancers and autoimmune disorders, although evidence for this is lacking. Their involvement in multiple sclerosis and motor neurone disease has also been proposed.