On the last day of March, surgeons at Massachusetts General Hospital began an operation that they hope will lead to a permanent change in how to transplant the kidneys in people.
That morning was not sick. It was a pig, anesthetic on a table. The pig was missing the kidneys and needed to grow.
While the kidneys should usually be planted within 24 to 36 hours, the kidneys entering the pig were removed 10 days ago, frozen and then melting early in that morning.
No one had previously planted a frozen member in a large animal. There was a lot that might make a mistake.
“I think there are about 50 percent of the chance to work,” said Korkot Ouigon, a professor of surgery and team leader, before the surgery. Dr. Ouigon at the Scientific Consultative Council of Sylvatica Biotech Inc. It is a company that develops freezing ways to preserve organs.
But the promise of freezing and storing the organs is great.
There is a severe and continuous kidney shortage of transplants – more than 92000 People on waiting lists. One of the reasons is that a window from 24 to 36 hours is so short that it limits the number of recipients suffering from good matches.
To what extent it might be better to have a bank of frozen frozen organs, so that the organ transplant can be almost like optional surgery.
This, at least, was a dream of transplantation for decades.
But medical researchers’ attempts to freeze organs have been thwarted at each turn. In many cases, ice crystals and organ destruction were formed. At other times, the material that aims to prevent crystals from forming, which is toxic and killed cells. Or, the frozen organ became so fragile that he is cracked.
After that, John Bishov, a researcher in the science of crying at the University of Minnesota who did not participate in the kidney pig project, said even when the freezing seemed to go well, there was a problem in dissolving the member.
When they gather a member, scientists tried to make sure of any ice crystals formed that were very small and did not harm the member. But those crystals were inclined to grow where the organs were heated, and sensitive cells were reduced.
“You have to outperform the ice crystals as they grow,” said Dr. Bishov.
He said: “The basic insight was: You cannot go quickly in the middle of the organ if all you do is warm on the edges.” “If the heating begins only on the outer part of the frozen organ, the differences in the temperature from the edge to the center of the organ can lead to stress that breaks the organ like the ice cube that cracks when you put it in your drink.”
He added, “You have to heat up a uniform, from the inside.”
His colleague, Dr. Eric in Fisher, a surgeon for a transplant at the University of Minnesota, who was also not involved in the collective general experience, said that although freezing should have occurred slowly to prevent ice damage, re -falsification should go quickly, 10 to 100 times faster than the cooling process.
Investigators tampered with their systems, and eventually learned to freeze the kidneys and soluble and plant mice.
But big animals have provided new problems.
“For four decades, the re -deportation was the case,” said Dr. in Fisher. “But with an increase in the size of the organ, the cooling becomes a problem.” Suddenly, the fluctuations that worked with small mice organs are no longer sufficient.
In the public state of Massachusetts, the researchers tried to a different approach. I started with Shannon Tesse, a post -PhD fellow at Dr. Ouigon Laboratory and Associate Professor of Surgery at the Harvard Faculty of Medicine, who works in a consultant council in Sylvatica Biotech and has a patented application related to the way used in March surgery. A few years ago, she was studying Canadian wood frogs.
When the weather becomes cold, the frog metabolism changes, allowing it to freeze itself. All its cellular operations stop. His heart stops. It is mainly dead.
The frog is so fragile that laboratory workers were very nice. “You can cut her arm if she is not careful,” said McLean Tagart, a laboratory technician.
Mr. Tagart said: “Shannon came to the laboratory and said:“ Is it possible to translate this into human organs? “
This led to work to learn how the frog goes to its deep freezing. Before the hibernation precedes, the frog begins to produce large amounts of glucose. Glucose accumulates inside the cells, as it reduces the freezing point in water, preventing ice from formation.
But the frog is amphibians. Will something like this method work on warm mammals or its members?
It turns out that he was doing. Mammals, Arctic Single, Supercools themselves when the temperature drops using a similar method. Its cells reach a temperature less than the freezing point in water – cold, but not enough to form ice. The metabolism slows down that you should not eat.
Like researchers before them, the collection started in Mass General with mice liver and tried to imitate the process. They decided to work with recently removed members, but they still use the same process as the wooden frog -the bodies are shook enough to stop metabolism, but not enough to risk the formation of large ice crystals.
They started to dump an unstable artificial glucose. Sugar accumulates in cells, but since it is not used, the cells enter a form of suspended animation, and metabolic processes stopped.
At the same time, investigators add a diluted anti -propylene – which replaces the remaining water in the cells. The result is that a few ice forms inside the cells, where the damage caused by the freezing of the organs occurs.
Their storage solution is a mixture of diluted propylene glycol and artificial sugar, as well as Snomax, the material used to make artificial ice on the ski slopes. Snomax creates small uniform snow crystals, helping to ensure that the ice that is formed does not cause damage.
For the melting of the organs, the group reflects the practical, and the liver in a warm solution contains glue -propylene and artificial glucose and gradually relieving chemicals until they disappear.
The researchers said that it took about five years of experience and error to obtain the process properly.
The next step was to move to the largest mammals. They will try to freeze and melt the pig kidney.
Their ultimate goal was an ambition – they wanted to form frozen kidneys banks that have been genetically modified for use in human patients.
Other transplant surgeons at Dr. Ouigon Hospital are they Starting the experiment With genetically modified pigs. They cultivated them in many human patients, with mixed results. On Friday, the patient whose kidneys lasted have had a longer – 130 days – to remove him because of Her body rejected her.
Nobody knew whether the way Dr. Oigon and his colleagues used would succeed.
“The protocol of the liver has been improved,” said Dr. OiGon. “We didn’t think he would work.”
But she did.
The team tested the method, freezing and soluble the melting of 30 pork kidneys, making sure that the organs remained healthy after the freezing process. They have learned that they can keep the kidneys frozen for up to a month without any clear damage.
But will the pre -frozen kidney function be planted if planted in a pig?
In the test in March, the kidneys remained frozen for 10 days and were to be planted again to the pig that was taken from it.
At three in the morning, the team started melting the kidneys, a two -hour operation.
At 9 am, Dr. Albani Long Chemel and Dr. Tatsu Kawai opened the surgery of Mass GENERAL, the pig’s belly and the animal’s running for surgery.
At 10:30, they sew the kidneys.
Soon the pink white gray organ turned as blood flowed in it.
Finally, success: before sewing the pig, the researchers saw that the cultivated kidneys produced Paul.
