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What Is Xenotransplantation?

What Is Xenotransplantation?
What Is Xenotransplantation?

New experiments are being done continuously in the field of organ transplantation. Now its limit has been extended further than before.

The earliest organs extracted from pigs made by genetic engineering were transplanted into people’s bodies. The human body in which the heart of such a pig was first transplanted lived for only two months.

There is a shortage of organs for transplantation all over the world. So how close are we to using pigs for an unlimited supply of organs?

About Xenotransplantation

Now we move to an operation theater where the transplant operation is going to take place. There is silence in the operation theatre. Here the tension is visible before the pig’s organ is brought for transplant.

Surgeons have just connected a pig’s kidney to a human body. Now the blood of the human body is flowing towards the organs of the pig.
“You could even hear the needle drop,” says organ transplant surgeon Dr. Jamie Lok.

She says, “The success or failure of this operation will be decided in the next few moments and now the only question on everyone’s mind is pink or black?”

What is the role of hyperacute rejection?


If the human body launched a terrible attack against the external organ, then every cell in the pig’s tissue would be pierced. Along with this, the clot will get deposited in this organ from inside to outside. After this, this pied first will turn blue and then black in a few minutes.

If the ‘hyperacute rejection’ survives, then this transplanted organ becomes pink with blood and oxygen. Hyperacute rejection starts a few minutes after the transplant. This process begins when the antigen is not fully matched.

After the organ transplant operation, Dr. Lok from the University of Alabama in the US said, “The transplanted organ turned pink and now it looks beautiful. Now there is a feeling of relief. There is an atmosphere of happiness and hope in the room.”

This operation is one of a series of successes in the medical world. This has rekindled interest in the field of xenotransplantation.

The use of animal parts for the human body is an old idea. In this sequence, from the transplantation of testicles of chimpanzees to the removal of kidneys and hearts of other species of monkeys, have been used. However, these transplants have resulted in death.

How successful is xenotransplantation?

The problem is that the immune system of the human body takes the transplanted organs as infection and attacks them. At present, the main focus for transplantation is on pigs because the size of their organs is usually equal to the size of human body parts. Our experience of raising pigs is centuries old.

But the biggest challenge in organ transplantation is hyperacute rejection. It is also a challenge that the limbs remain pink and do not turn black. It’s not like you go straight to a pig farm. Take a boar from there and transplant its organ into the human body.

Genetic engineering for organ transplantation has gone through several stages of development to modify the pig’s DNA. Due to this change, their organs can adjust more with the resistance system of the human body. In the recent pig kidney and heart transplants, the organs were taken from specially prepared ’10-gene pigs’.

A gene was modified to prevent a donated organ from responding to human growth hormone and prevent uncontrolled growth. Another important change was made by removing the sugar molecule. This is called alpha-gal. It sticks to the surface of the pig’s cell and acts like a big glowing neon sign. In this way, it makes the tissue completely alien.

A unit of our immune system called the complement system monitors the body awaiting alpha-gal. This is the reason why organs are rejected or killed by the body within moments of being transplanted.

Two other ‘neon signs’ were genetically deleted during this experiment. Instead, six human signals were added. It acted as a camouflage cover over the pig cells. This was helping them to hide from the body’s immune system.

However, the 10-gene pig that is produced is raised in a sterile environment. So that it can be transplantable.

kidney and heart


In September 2021, two pigs’ kidneys were transplanted into the body of brain-dead Jim Parsons. He wanted to donate organs. In a brain-dead state, pig kidneys were transplanted instead of his kidneys with the permission of his family.

Doctor Lok tells that one of the transplanted kidneys started making urine. This success was remarkable. It seemed that xenotransplantation could change people’s lives. And simply put, it could save their life. He hopes that its clinical trial can start this year.

That operation was a three-day-long experiment, but in the meantime surgeons at the University of Maryland Medical Center were ready to go a step further.

His patient David Bennett, 57, had a massive heart attack. His body did not seem suitable for a human organ transplant. He was kept alive through the Ecmo machine. Due to this his kidneys and lungs were supported.
Bennett described the pig’s heart as a ‘target shot in the dark.

During this operation, the 10-gene pig was taken to the hospital on 7 January. Then its heart was inserted inside Bennett’s chest. The operation was complicated because Bennett’s ailing heart was swollen. So it was a challenge to connect his blood arteries to the small heart of the pig.

Once again there was an atmosphere of panic. It seemed as if the transplanted heart would be rejected immediately. But it kept on throbbing and eventually turned pink. Dr. Mohammad Mohiuddin, director of the department of cardiac xenotransplantation at the hospital, said that he was not expecting to see this success in his ‘life’.

When I spoke to him after the completion of one month of this operation, he told that the body is showing no signs of rejecting the transplanted organ. But Bennett still looked very weak.

“We have put a new Ferrari engine in a 1960 car. The engine is working very well but the rest of the body is yet to adjust to it. ,

But Bennett died two months after the transplant. Therefore, there is still uncertainty about the effects and causes of xenotransplantation. Bennett was still very weak before the operation and it may be possible that even a new heart may not be enough for him.

In this case, no signs of rejection of the transplanted organ were reported. But if a detailed analysis of the heart indicates an attack on it by the immune system, further modification is needed in the 10-gene pig to make the organ more suitable for transplantation into the human body.

And ultimately the matter may come down to anatomy and the pig’s heart may not fit the human body. Our heart has to work harder than that of a pig to fight gravity because man has to walk on two legs. Whereas the pig has four legs.

Professor Chris Denning, from the Department of Stem Cell Biology at the University of Nottingham, said overcoming the failure of hyperacute rejection would mean a heart transplant was successful.

He said that if the matter was of the weakness of the patient then it is another matter. But ‘Xenotransplantation’ may be successful in the future. But it can be a ‘potential showstopper’ if it is a matter of anatomy.
The hospital now wants to continue its clinical trial.

In the world of organ transplantation, there is an increased expectation from pig organs

According to Professor John Wallwork, one of Britain’s most renowned transplant surgeons, to save a large number of lives, a pig’s heart does not necessarily have to be similar in quality to a human heart. He says that many people still die waiting for the transplant.

Professor Wallwork is one of the first to work in the field of xenotransplantation. He did the world’s first heart-lung liver transplant. He says that it is better to give 100 people an 85 percent chance of being alive with a human heart than to give 1000 people a 70 percent chance of being alive with it.

Xeno transplantation has always been viewed as the next big thing in transplant medicine. This is the reason why one remarkable operation after another took place. But only further research will be able to tell whether its big dream will be able to take full form or not.

Dr. Lok says, “Our goal will be that an edited 10-gene pig can help patients with kidney, liver, and heart failure, and can save patients with end-stage heart disease.”

He said, this will be a very important achievement and I sincerely believe that in our life also we will all be in that period.

Courtesy of BBC

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