Xenotransplantation: Transplanting Vital Organs from Animals into Humans

The medical procedure of transplanting organs from animals to humans is called xenotransplantation. While it is not yet a commonplace surgical procedure, it has been carried out on several occasions to save and extend human lives when the necessary and compatible human organs were unavailable for donation. Primates are most commonly used in xenotransplantation, because, being our closest relatives in the animal kingdom, their body physiologies are very similar to our own.

Xenotransplantation is not a new concept. The idea of attaching animal parts to human bodies, not so much to replace organs, but to give human extraordinary powers had occurred to our ancestors and world mythologies abound with various stories about humans with wings, tails, hooves, animal heads, and so on. Much later, with advancements in medical surgical procedures, surgeons considered organ transplantation from animals into humans. Actual attempts at such surgical transplantations were carried out in the early 1900s and did not meet with any success. The patients either died on the operation table itself or shortly thereafter, but their survival, even if for a brief duration, bolstered the hope that, with further medical advancement, such procedures might have the distinct chance of working.

In the 1960s, pioneering US American transplant surgeons like Keith Reemtsma, James Hardy, and Tom Starzl carried out xenograft surgeries and, while their efforts did not meet with long-term success either, the medical fraternity doesn’t seem to have given up on xenotransplantation.

Reasons for carrying out xenotransplantation

The principal reason for carrying out xenotransplantation, as mentioned earlier, is to transfer primate organs into humans to replace diseased or dysfunctional human organs. The number of patients requiring organ transplants is steadily growing, as various lifestyle diseases take their toll on our society, and there are simply not enough human organs to go around. Also, if human organs are available, they must be quickly removed and transferred from the body of the donor to that of the patient in a very short amount of time. This can limit their availability to only patients in the close-by area.

Without getting an organ transplant, many affected patients are not likely to survive. Their only hope then is to try xenotransplantation.

It is a risky procedure though and patients are made aware of this from the onset.

Risks of xenotransplantation

Even though primates are our closest relatives and our physiological functioning is similar, it is not the same. While a kidney taken from a chimpanzee could be transferred with a degree of success into a human being, that kidney is not going to function in exactly the same fashion as a human kidney would and there are likely to be medical complications owing to this.

Another issue is the matter of organ rejection. To explain this in a very simple way, our body knows the difference between something that is part of our body and something that is not. When an organ, whether from a primate or from another human, is transplanted into the body, the first reaction of the body’s immune system is to reject it. This was not known in the earlier years of organ transplant surgery and many patients died because their body rejected the newly transplanted organs. Now, doctors give immunosuppressant drugs to patients so that their body is tricked into accepting the transplanted organ. The patient can then have a reasonably normal post-operation existence. The only downside of this is that the patient must continue to take the immunosuppressant drugs for the entire course of their life.

There is also a veritable risk of transmission of viral and bacterial infections from primates to humans from the organ transfer. Diseases that were hitherto confined to primates could end up affecting humans as well. The patient will not be the only person at risk in such a scenario, but everyone else in his or her vicinity could also potentially end up getting affected. Both doctors and patients must weigh this issue very carefully or they could find themselves opening a Pandora’s Box of troubles. While all manners of precautions, tests, and checks are carried out before an organ transplant, infection transmissions cannot still be ruled out a hundred percent.

1905-1923: Early attempts at xenotransplantation

The first attempts at xenotransplantation were carried out in the early 1900s and the procedure was then called heterotransplantation. In one of the first recorded instances, in 1905, a French surgeon named Princeteau operated on a child with kidney disease and transferred part of a rabbit’s kidney into the child. At first, the operation appeared to be a success. The child’s symptoms of vomiting ceased, and the child began to pass a normal amount of urine. The patient survived for 16 days and then died from pulmonary problems.

In 1906, another Frenchman, Mathieu Jaboulay, attempted to transfer kidney sections from a pig and a goat into two female human patients. The transplantations did not work. According to Dr.Jaboulay, vascular thrombosis was the cause of the failure.

Four years later, in 1910, the German surgeon Ernst Unger transplanted primate kidneys into a young girl with renal failure, but that experiment failed as well. The patient died from venous thromboses some 32 hours after the operation.

The American surgeon, Neuhof, transplanted a lamb kidney into a human patient in 1923, and, although the patient lived only for nine days after the operation, Neuhof took an optimistic view of the procedure. According to him, it was a good sign that the patient did not contract gangrene, did not haemorrhage, and did not show signs of thrombosis. That indicated that xenotransplantation could indeed become a medically viable procedure in the future.

It seemed that xenotransplantation was going to take the medical world by storm, but as the working of the body’s immune system became more scientifically clear, the strong possibilities of organ rejection after transplantation deterred surgeons from attempting this surgery and the medical community backed away and turned to look for other possible solutions for the organ transfer issue. It wasn’t until the introduction of immunosuppressant drugs that the spotlight was shed again on the medical possibilities of xenotransplantation.

1960s: Keith Reemtsma’s pioneering surgery in primate kidney xenografts

In the 1960s, Keith Reemtsma was a professor of surgery at Tulane University in New Orleans, Louisiana. He had a great deal of interest in innovative medical procedures and he was, therefore, open to attempting xenotransplantation when Tulane University’s hospital encountered difficulties in obtaining human organs for transplantation. Dr.Reemtsma and his team decided to acquire chimpanzee kidneys from a nearby primate centre and use them in place of human kidneys.

There were several reasons for choosing chimpanzee kidneys in lieu of human ones. First, in addition to being available, they were similar in size to human kidneys and, given the similarity between chimpanzee and human bodies, it was likely they would function in the latter. Also, chimpanzees have A and O blood groups, which are the same as those of humans. The doctors assumed that given these similarities, and with the availability of immunosuppressant drugs, there was a fair chance that the transplantation could be successfully carried out.

They discussed the operation with six patients that were currently admitted in the hospital and with their families, highlighting the uncertainty and risks involved in the procedure. If the patients didn’t wish to have a xenograft, they could continue with supportive treatment for as long as was possible. Or, they could get a human kidney transplant, either from a recently deceased donor or from a relative of theirs, when and as that became possible. Given the unavailability of human organs and the fact that these patients were at a critical stage of kidney disease, requiring daily dialysis, with no other treatment options possible, they consented to the operation.

The doctors at the primate centre removed both kidneys from six chimpanzees and sent them over to the Tulane University hospital where Dr.Reemtsma and his team transplanted them into the six patients. Each patient thus received a pair of chimpanzee kidneys and all of them were afterwards given anti-rejection drugs. Five of the six patients, however, faced organ rejection and infection soon afterwards and lived only between one week to two months after the operation. Only one, a school teacher, survived longer.

1964: The case of the school teacher

The school teacher had coped with kidney disease since the age of 14 and now, at the age of 23, she was admitted to the hospital at Tulane University with a case of chronic glomerulonephritis as well as progressive uremia. At the hospital, her condition took a turn for the worse and she had to be put on dialysis.

On 13 January 1964, she underwent surgery to receive the chimpanzee kidney transplant, and, like the other patients, she was put on immunosuppressant drugs. She also showed symptoms of organ rejection soon after the operation, but her condition stabilized, and her new kidneys began to show normal functionality, except for the fact that she needed to urinate more frequently, and the urine volume was greater than the pre-operation volume. After the doctors were assured that she was stable, she returned home, and she even went back to her teaching job. For nine months, she appeared to be doing well, and then, suddenly, she died. Her death, it transpired, was the result of the frequent and high-volume urination which caused an electrolyte imbalance and led to a cardiac arrest. It is very likely that the excessive urination was due to differences in the workings of chimpanzee and human kidneys that the surgeons had not accounted for. The autopsy showed that the kidneys themselves were undamaged.

1984: The case of Baby Fae

Baby Fae was born with a defective heart; the left side of the heart was undeveloped. The only way for her to survive was to get a heart transplant. Since a human heart was not available for the infant, Dr. Leonard Bailey and his surgical team decided to transplant a baboon heart. After the operation was carried out, Baby Faye was put on the immunosuppressive drug cyclosporine to increase her survival chances. She lived for 20 days before her body rejected the new heart. A possible reason for this rejection may have been the incompatibility of the baboon’s ABO blood type with that of Baby Faye.

Other cases

Several other surgeons carried out xenotransplantation surgeries in the years that followed. Two notable cases were by Dr. James Hardy and Dr. Thomas E. Starzl.

Dr. James Hardy, who was the first surgeon in the world to perform a human lung transplantation in 1963, was impressed with Dr.Reemtsma’s work and attempted, in 1964, to transplant a chimpanzee heart into apatient with a very advanced atheromatous vascular disease. It turned out that the chimpanzee heart was not large enough to support human circulation and the patient died within a few hours.

In 1963-1964, Dr. Thomas E. Starzl, who was then a transplant surgeon with the University of Colorado, carried out baboon kidney xenografts in six human patients; baboons were used, since, given the endangered nature of chimpanzees in the wild, they were no longer considered expendable. The baboon kidneys were found to be slightly more compatible than chimpanzee kidneys, but, ultimately, they failed as well and all six of the patients died, and the program was not continued with other patients. Later, in the 1990s at the University of Pittsburg, Dr.Starzl and his team transplanted a baboon liver into a 35-year old man with hepatitis ands HIV. He died 70 days after the operation from biliary stasis.

John R. Brinkley – Pioneer in goat gland xenotransplantation

A self-made and popular Kansas doctor with an incomplete medical school training and no medical degree, John R. Brinkley shot to national fame for transplanting goat glands into humans. He hit on this concept around 1918 after he was asked to treat a sexually impotent man and jokingly told the patient that the issue would be resolved if he was fitted with buck goat glands. According to Brinkley, the patient then begged him to perform the operation. The patient’s son gives a different version of the story to The Kansas City Star. Brinkley offered his father a sizable sum of money for becoming a test patient for the operation. Whatever the true story, Brinkley charged a $150 fee for the operation. It proved to be a success and the patient went on to have a son with his wife in 1920. Brinkley, who was a shrewd advertiser of himself and his medical practice, seized this opportunity for more self-publicity.

His claims to restore male virility and fertility through the goat glands operation brought him many patients and he began charging them $750 for the procedure. This was a sizable sum in those days and he soon made himself a fortune. As time went by, he grew careless, arrogant, and delusional. He did not take basic sterilization procedures with his operating tools and was often drunk while performing operations, and this resulted in post-operation infections and even deaths. Undaunted, Brinkley continued to promote himself, hiring an advertising agent to churn out advertising copy that promised to turn every man into a ram. Going further, he informed the public that his goat gland operation could cure them of dementia, emphysema, flatulence, and 24 other ailments. He even attempted to cure a spinal cord tumour by giving the female patient goat ovaries. The American Medical Association (AMA) put him on their watch list and Morris Fishbein, the editor of the Journal of AMA, became a sworn enemy. Eventually, he was stripped of his license to practice medicine in many US states, including Kansas.

Before that happened, however, he also got himself some Hollywood limelight with the assistance of the Los Angeles Times’ owner, Harry Chandler. The latter invited him to do the goat glands operation on one of the newspaper’s editor. For this, Chandler even acquired a 30-day medical permit for Brinkley, who did not have the license to practice in California. The media showed up to watch the operation and declared it a success. Brinkley received a huge amount of publicity and droves of new patients, but the California Medical Board did not join the adulators and refused to grant him a permanent license to practise in the state.

Brinkley’s fame and his many public service work in his hometown, Milford, made him a very popular and respected figure in Kansas. He made so much money for the state that when Californian law agents came to arrest him for having a fake medical degree, the Governor of Kansas turned down their extradition request. Later, Brinkley travelled to Italy and managed to get an honorary degree from the University of Pavia in Pavia in Lombardy. When he heard about it, Morris Fishbein wrote the Italian government a blistering letter and that got Mussolini’s attention. He personally rescinded the degree, but it remained Brinkley’s prized possession and he continued telling people that he had an Italian medical degree.

For many years, Brinkley’s success continued unabated. In addition to his medical practice, he had a radio show and many other businesses. Morris Fishbein, however, continued to rile him on the side-lines. After he included him in his article about medical charlatans, Brinkley thought he had gone too far and made the mistake of suing him for libel. The 1939 trial went in Fishbein’s favour and Brinkley then found himself inundated with malpractice lawsuits from former patients. He was sued for more than $3 million and was forced to declare bankruptcy in 1941. His health deteriorated, and he died penniless in 1942.

Ethical issues and xenotransplantation

While the success rates for xenotransplantation may go up in the future, the ethics of doing so remain questionable.

When people talk about the success possibilities of xenotransplantation, it is always from the angle of how good it will be for humans, without sparing too much, if any, thought about the animals that will be used as donors; the word ‘donor’ is actually inappropriate here, since none of these animals will be willingly volunteering their organs; the urge to live is as strong in them as it is in us.

Many of these animals are ‘lab animals’; that is, animals kept in often horrendous conditions in laboratories and subjected to the most inhumane and cruel experiments, and all, of course, for the greater good of humankind. Or they are animals that are specially raised to ‘donate’ their organs and after they have done so, their life purpose, as far as humans are concerned, is over.

People have become so accustomed to ‘keeping’ animals for food that they don’t seem to realize or care enough that these are not creatures put on earth for our convenience. They are fellow living creatures and they have as much right to live safe and happy lives as we do, and considering their existences to be of trifling importance only highlights our ethical and moral bankruptcy.

How does it become alright for human beings to extract organs from other living creatures and condemn them to die in a painful manner? Why is one life more important than another?

These are questions that cannot be lightly brushed aside, but, on the other hand, understandably, when people are facing the very real possibility of their own death or that of a loved one, they may not be in the frame of mind to weigh in any ethical considerations.

Enjoyed this article? Also, check out “Trepanation: Unusual Medical Procedure of Drilling Hole in the Skull“.

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• Primate to Human Organ Transplantation
• Xenotransplantation