Two pig kidneys were successfully transferred to a patient by surgeons. This is a significant step in the long-running quest for animal organs that can save lives. 

Jim Parsons, aged 57 from Huntsville in Alabama, received two kidneys after his kidneys had been removed. 

Mr Parsons, who died in September last year, was brain dead and on life support after having suffered a traumatic head injury, but stayed alive long enough for scientists to assess the effects of the transplant with his family’s blessing. 

The transplanted kidneys of pigs produced blood and urine, but were not rejected immediately by the body. 

The organs remained viable until the study was ended, 77 hours – or more than three days – after the transplant at University of Alabama at Birmingham (UAB). 

Results demonstrate how xenotransplantation – the transplantation of living cells, tissues or organs from one species to another – could address the worldwide organ shortage crisis. 

Pigs’ heart anatomy and physiology is similar to that of humans so they are used as models for developing new treatments. 

Earlier this month, David Bennett become the first patient in the world to get a heart transplant from a genetically-modified pig. 

Meanwhile, in October, surgeons in New York successfully transplanted a pig kidney into a human, prior to the patient being taken off life support.

The New York procedure however transplanted one kidney from a pig outside of the patient’s body. 

This Alabama procedure – which was conducted on September 30, prior to the New York procedure – involved removing Mr Parsons kidneys and inserting the two pig kidneys at the correct place inside his body. 

The operation being conducted by experts at University of Alabama at Birmingham Marnix E. Heersink School of Medicine

This operation was performed by the University of Alabama at Birmingham Marnix E. Heersink School of Medicine

The organs worked for more than three days during an experiment on Jim Parsons (pictured), a a brain dead patient already on life support

The organs were able to function for over three days in an experiment performed on Jim Parsons (pictured), who was a brain-dead patient on life support.


This study approximates the possible steps in a Phase 1 xenotransplant clinical trials.

– Kidneys taken from donor pig. The kidneys were stored and transported to be inserted.

Before the surgery was performed, both Mr Parsons (and the donor animal) underwent crossmatch compatibility tests to confirm that the organs had been genetically altered.  

The kidneys of the pig were placed at the same anatomical location as human donors, including the attachments to the renal vein, renal artery and the urinary ureter.

– A standard immune suppression therapy was administered to the brain-dead recipient in order to prevent future kidney transplants. 

The first peer-reviewed research outlining Mr Parsons’ successful transplant by surgeons at UAB’s Department of Surgery has been published today in the American Journal of Transplantation.

‘This game-changing moment in the history of medicine represents a paradigm shift and a major milestone in the field of xenotransplantation, which is arguably the best solution to the organ shortage crisis,’ said Professor Jayme Locke, director of the Comprehensive Transplant Institute in UAB’s Department of Surgery and lead surgeon for the study. 

“We’ve bridging critical knowledge gaps to obtain the safety data and feasibility data required for a clinical trial with living patients suffering from end-stage renal failure.

“This research provides new knowledge and helps us move closer towards a world where there is sufficient organ supply to meet the enormous demand.” 

Mr. Parsons is a registered donor of organs through Legacy of Hope (Alabama’s organ procurement organization).

His wish was to see his organs be donated after his death. 

UAB was allowed to place him on a ventilator by his family to help keep him alive during the study. 

He had his native kidneys removed. The two genetically engineered pig kidneys from him were then transplanted. 

The transplanted pig kidneys were obtained from 10 genetically altered pigs. These genes edits may have made the kidneys more suitable for transplantation into human beings. 

According to The Huntsville Times obituary, Mr Parsons' (pictured) 'storytelling, sense of humour and love for his mother and children were unmatched'

According to The Huntsville Times, the obituary of Mr. Parsons (pictured) “storytelling and sense of humor and love for his children and mother were unmatched”

Mr Parsons with his daughter, Ally Parsons. The pig organs worked for more than three days during the experiment

Ally Parsons, his daughter. The experiment lasted more than three days because the pig organs were active.


Scientists have been toying with animal-to-human organ donation, (xenotransplantation) for decades.

In the 1800s, skin grafts were performed on a wide range of animals for wound treatment. Frogs are the most common.

In the 1960s 13 patients were treated with chimpanzee renals. The one who returned to work after almost nine months was suddenly killed. Within weeks, the rest died. Human organ transplants weren’t available at that time, and chronic dialysis wasn’t yet an option.

Doctors at Loma Linda University Hospital Medical Center, California in 1983 transplanted the baboon’s heart to a baby with fatal defects.

Baby Fae was alive for 21 days. It was discovered that the surgeons didn’t attempt to implant a heart in Baby Fae.

Recent years have seen an increase in the number of people waiting for transplants from deceased or allogenic donors. This is because there has been an increase in life expectancy and increased demand.

Surgeons from NYU Langone Health, New York succeeded in transplanting a kidney from a pig into a person for the first-time. This was done on October 20, 2021.

It worked as intended, producing urine and filtering the waste without any rejection from the immune system.

Before she was removed from life support, the recipient was a New York brain-dead patient with kidney dysfunction. Her family consented to the experiment. 

The pig kidneys had been removed from a donor pig housed at a pathogen-free, surgically clean facility, before being stored, transported and processed for implantation, just as human kidneys are.

Prior to surgery, Parsons underwent crossmatch compatibility tests with the donor animal in order to establish if they were good tissue matches. 

Crossmatches are done for each human-to–human renal transplant. But, this test of pig-to–human tissue match was created at UAB. It marked the first possible crossmatch that has been validated between the two species.

The kidneys of the pig were placed exactly in the same locations as the human kidneys. They had identical attachments to both the renal artery and renal vein.

Mr Parsons also received standard immune-suppression therapy – in other words, treatment that lowers the activity of the body’s immune system. 

When asked how such a transplant would have gone in an otherwise healthy patient compared to a brain dead patient, Professor Locke said there would have been ‘no difference’ in terms of process, but the outcome would have been different.

MailOnline reported that study endpoints (specifically kidney function) will vary. 

The brain death environment makes it very difficult for kidney function assessment (e.g. It’s not difficult to determine kidney function by measuring creatinine clearance and urine output. (This is not surprising considering that kidneys from dead donor brains can produce little urine, and then take many weeks to eliminate it.  

On how the UAB procedure differed to the similar procedure that took place at NYU Langone Health in New York in October, Professor Locke said the human brain dead recipient did not have her native kidneys removed, unlike Mr Parsons, which ‘confounds any interpretation of kidney function’. 

MailOnline reports that the NYU-pig-to human kidney was also transplanted to her leg. It wasn’t in the traditional heterotopic spot for human-to/human transplantation.

For the first time, the pig kidneys transplanted were taken from pigs that had been genetically modified with 10 key gene edits that may make the kidneys suitable for transplant into humans

First time that pig kidneys have been transplanted from animals that were genetically altered with 10 key gene editings, which may make them suitable for transplant to humans

“Mr Parsons” transplants were performed inside the abdomen at the same location as human-to-human transplantation. 

The UAB team claims that their procedure shows the viability and potential for success in transplants. 

Professor Locke stated that the human preclinical model was a method to assess the safety and feasibility for the pig-to non-human primate model without risk to any living person. 

The breakthrough could solve the organ shortage crisis as people on the waiting list are dying every day

As people die each day on the waiting list, the breakthrough could end the organ shortage crisis.

In the US, by far more patients are waiting for kidneys than any other organ, according to UAB

According to UAB, Americans are waiting longer for their kidneys than they are any other organ.

“Our study has shown that human xenotransplantation is possible. It also identifies the areas in which new information is necessary to improve xenotransplantation results. This study will be used to establish a pre-clinical human model to further investigate the matter. 

Transplanting pig organs to humans will increase organ availability and reduce the thousands of American deaths each year caused by organ shortages. 

Today, over 800,000 Americans live with renal failure. Many don’t even make it onto the waiting lists because so many organs are available.  

While dialysis may be able to sustain life for a while, transplantation can offer a higher quality of life and longer lives for those who are able.  

UAB reports that kidney disease is the leading cause of death in America.


One dying man became the first to have a heart transplant using a gene-modified pig. 

Terminal heart failure sufferer David Bennett underwent the nine-hour experimental procedure at the University of Maryland Medical Center in Baltimore on Saturday, January 8.

A surgeon used a heart from a pig who had been gene-edit to reduce the likelihood that his immune system would reject it. 

After the operation, doctors said Mr Bennett (57) is now breathing independently while being connected to a machine which helps him pump blood around his body. 

Experts believe it’s too early to predict if the organ will accept his body. The next several weeks will prove crucial as the machine is removed from him.

However, the success of this research could be a major medical breakthrough that will save many lives each year in America. 

Read more: US surgeons transplant a PIG heart into a human