Jueves, 24 Agosto, 2017

We're one step closer to using pig organs in human transplants

CRISPR'd piglets from the eGenesis study.									eGenesis CRISPR'd piglets from the eGenesis study. eGenesis
Orlondo Matamoros | Agosto 13, 2017, 02:54

Pigs have always been eyed as potential vessels for organ cultivation, as the size and structure of their organs makes them the most viable - theoretically - for transplantation to humans. "Our team will further engineer the PERV-free pig strain to deliver safe and effective xenotransplantation". Now, without the threat of these hidden diseases, it may be possible to safely transplant pig livers, hearts, and other organs.

Scientists have cloned genetically modified piglets that may prove a safe source of organs for transplants into humans. The pigs' organs will be about the same size as humans' once they reach their maximum size of about 150 pounds. More than 117,000 people are on the waiting list for organ transplants in the US, according to the Department of Health and Human Services. Such removal is a technical challenge, as pigs have dozens of PERV copies in their genomes.

The PERV family aren't the only pathogen in town, but they are among the most concerning.

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.

Their work, documented in the USA journal Science on Thursday, could save lives by reducing organ donor waiting lists that have risen over the years, partly thanks to better road safety.

Now they have taken the genetic material from such cells and, using a similar technique to the one used to clone Dolly the sheep, inserted it into pig eggs. Porcine retroviruses (PERVs) are now one of the big safety barriers preventing us using pigs as organ donors.

The difference is unlike our version of the virus, PERV can still pop out of its cosy spot and infect other cells.

In China alone, more than 300,000 patients are waiting for organ transplants but fewer than 10,000 surgeries are performed each year. And regulators require stringent tests in lab primates before a single patient could get a CRISPR'd pig organ; that will take years. But removing the viruses is a big step. The unreliability of cloning means that, out of thousands of attempts, just 15 piglets remain alive.

"It's an elegant tour de force of genetic engineering, so my hat is off to them", said Dr. A. Joseph Tector, of the University of Alabama, Birmingham, who has also made genetically modified pigs aimed at producing transplantable organs.

The BBC reports on the study in the journal Science, noting this "exciting and promising first step" toward xenotransplantation, in which organs are transplanted between different species. This adds to the growing number of transplants that are already in relatively widespread use in medicine (heart valves, skin grafts for burn patients, etc.).