Reports by Chris Irvine HERE
Scientists have successfully frozen, thawed, and transplanted a pig's liver. Scientists at the Israeli Agricultural Research Organization in Bet Dagan, which carried out the work, said the key to their success was a slow freezing method.
Amir Arav, who pioneered the new method, says the key to limiting cell damage during freezing is to cool the liver very slowly, as it prevents the formation of ice crystals.
He and his colleagues flushed the blood from the liver before cooling it to a temperature of -20ºC in roughly 90 minutes.
The team then thawed the liver, and transplanted it into another pig, using it as a second liver. The liver recovered its red colour, and began to produce bile, signs of a healthy liver.
The pig was killed about two hours later and the auxiliary liver analysed revealing the cells were alive.
Dr Arav told New Scientist magazine he was not allowed to do more than a temporary secondary transplant because of restrictions imposed by animal welfare.
He said: "We hope to repeat it and do those other tests next time."
He plans to evaluate how long livers can be stored as well as the optimal storage temperature. The process raises the distant possibility that work using the same method could be conducted on human livers, which are roughtly the same size as a pig's, to see if they could survive.
Livers deteriorate rapidly without a blood supply, becoming useless between 12 and 24 hours later, so getting them to a potential recipient is extremely difficult.
A frozen liver 'bank' would greatly increase the number of patients who could benefit from transplants.
Phil Newsome, a senior lecturer and consultant hepatologist at University Hospital Birmingham, said the research was encouraging but it left a lot of questions.
He warned: "We have to be sure there are no ill effects from this process. You don't want to find there are complications in the long term. There needs to be a large amount of evidence that this is a safe and effective proceedure."