Cleaned-up pig genome is one step toward xenotransplantation

Domingo, 13 Ago, 2017

If the experiment proves safe and effective, it could make it possible to supplement human organ shortages by using livers, hearts and other organs transplanted from pigs.

Indeed, xenotransplantation, name these transplants of animal organs on humans, involve the risk of transmission of a virus which it is feared that it could infect humans.

So far, 37 such piglets have been born.

The most genetically modified animals in existence have been created to help end a shortage of organs for transplant, say United States researchers.

The possibility of using animals to grow organs for humans could have a dramatic impact on the lives of millions of people worldwide. More than 117,000 people are on the waiting list for organ transplants in the USA, according to the Department of Health and Human Services.

For two decades researchers have been trying to safely harvest the organs for humans, which are similar in size and function to our own. Such removal is a technical challenge, as pigs have dozens of PERV copies in their genomes. They are now repeating the process to engineer male pigs, which Church says he doesn't expect to be any more complicated.

Study author George Church, a geneticist at Harvard and founder of eGenesis, told the Times he thinks that pig-to-human transplants could happen within two years. This doesn't mean that pig organs are ready for humans just yet, but the study, published today in Science, raises hopes that the technology is finally ready to make animal organs fit for people.

They then used a standard cloning technique to insert the edited DNA into egg cells that were placed into a surrogate mother. Knocking out three in particular could protect pig organs from being attacked by the human immune system, he said; lab macaques that received kidneys from the pigs have survived as long as 499 days.

However, they have admitted that there are still huge issues ahead in the research as it is not yet known how to stop humans from rejecting pig organs.

The team, led by the company's Dong Niu, first used a cell line to demonstrate that PERVs are not only able to migrate from pig to human cells, but can also then move between cells in their new host.

In 2015, Church and CRISPR expert Luhan Yang co-founded a company called eGenesis, to sell their genetically modified pig organs. "Our ability to be successful would make a potentially significant impact on the thousands of patients waiting for organ transplants".

The oldest pigs are almost 5 months old, or adolescents; 15 remain alive.

The eGenesis scientists used the CRISPR-Cas9 version of the genome editing tech to slice off the PERV-causing genes in porcine embryos. Pig heart valves already are routinely transplanted into patients.