Xenotransplantation: Need, Advantages and Challenges – Explained, pointwise

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Introduction

In the first week of January 2022, a genetically modified pig’s heart was successfully transplanted into a 57-year-old man dying of heart failure in a New York hospital. This is the first successful transplant of a pig’s heart into a human being. However, it’s too soon to know if the operation really will work. Nevertheless, this Xenotransplantation is considered a path-breaking surgical procedure.

Transplantation to replace failing organs is one of the spectacular achievements of medicine in the last century. The number of transplants has increased, the list of organs that can be transplanted has grown, and outcomes have gotten better. The ‘xenotransplant’ is a reminder of the endless possibilities to treat otherwise untreatable diseases.

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About the recent Xenotransplantation Operation

The earlier attempts of animal-to-human heart transplants have failed, largely because patients’ bodies rapidly rejected the animal organs. The most notable example was that of American infant Baby Fae, a dying infant in 1984 who lived 21 days with a baboon heart.

This time, the surgeons used a heart from a pig that had undergone gene editing to remove sugar in its cells that’s responsible for the hyper-fast rejection of organs.

Read more: In first, US surgeons transplant pig heart into human patient
What has been the history of Xenotransplantation?

Xenotransplantation involves the transplantation of nonhuman tissues or organs into human recipients.

The dream of animal-to-human transplants goes back to the 17th century, with stumbling attempts to use animal blood for transfusions. Early kidney and liver transplants were attempted from baboons and chimpanzees as these primates were considered closest to humans.

By the 20th century, surgeons were attempting transplants of organs from baboons into humans. Over the last several decades experts have found it difficult to surmount the challenge presented by the immune system’s rejection of an alien organ, ending in deadly outcomes for patients.

In the early 1960s, a surgeon Keith Reemtsma in New Orleans performed 13 chimpanzees-to-human kidney transplants. One of the recipients, a schoolteacher, lived for 90 days. However, most of these transplants failed and were gradually given up.

Why does the world need Xenotransplantation?

The world needs Xenotransplantation for

Organ shortage and fewer donors: According to the World Health Organization, more than 114,000 organ transplants are carried out annually in the world, but they fulfil only less than 10% of global needs. In India, against a requirement of 25,000-30,000 liver transplants annually only 1,500 transplants are performed due to scarcity. Similarly, nearly 50,000 persons suffer from heart failures annually but only about 10-15 heart transplants are performed every year.

The organ shortage has also led to a) The use of organs from executed prisoners in some countries, b) A wide increase in organ trafficking: It is estimated that 5–10% of kidney transplants worldwide result from commercial transactions between a potential recipient and a paid living donor.

Organ donation has remained low even in developed countries with highly-education population for example, in Japan, the organ donation rate is only 4 per million; in Switzerland, it is 12 per million; in Canada 15; in the UK 18; and in the US 24. Further, countries like India have 1 donor per million population and in China, the level is 0.5 donors per million population.

Must read: Illegal organ trade is not only unethical but is a serious crime against humanity and society 

Increasing disease burden: Due to advancements in medicine, the average life expectancy has increased. Many persons are facing organ failure due to old age and lifestyle issues which has increased the demand for organ transplant. The most frequently transplanted organ is the kidney, which accounts for 68% of the total organ transplants.

Issues in obtaining human organs: Some organs can only be obtained from deceased or brain-dead donors, for instance, the heart, liver, etc.

What are the advantages of Xenotransplantation?

1. Organs will be available immediately and electively, 2. Eliminate illegal organ trafficking and the use of organs from executed prisoners, 3. One does not have to seek consent from an animal that can be sacrificed for the organ. However, not all agree with such a narrow utilitarian approach, 4. The unlimited supply will allow transplantation procedures in ‘borderline’ candidates who might otherwise be declined, 5. The detrimental effects of brain death on donor organs will be avoided, 6. Eliminate the ‘cultural’ barriers to donation of organs from deceased human present in some countries like Japan.

What are the potential advantages of Pigs in Xenotransplantation?

1. Pig organs have similarities to human organs in respect of anatomy and physiology. For instance, Physiologically, cardiac output and stroke volume, which are major indicators of cardiac function, have been reported to be comparable in pigs and humans, 2. Pigs could provide an unlimited supply of organs, tissues, and cells, e.g., it is easy to raise and achieve adult human organ size in six months from pigs. 3. Pigs are easy to breed and have large litters, 4. From a scientific viewpoint, pigs are genetically modifiable to reduce the chances of rejection by the human body, 5. When bred and housed under ‘clean’ conditions, pigs could provide exogenous infection-free organs, tissues, and cells, For instance, there are now companies breeding genetically modified pigs. One such U.S.-based company, Revivicor supplied the pig heart for the New York transplant, 6. Pigs are produced for food, so using them for organs raises fewer ethical concerns.

Breakthroughs so far

What are the challenges in Xenotransplantation?

Diseases transmission: Xenotransplantation raises concerns regarding the transmission of hitherto known and unknown diseases to humans with both recognized and unrecognized infectious agents and the possible subsequent transmission to the general human population.

Moreover, new infectious agents may not be readily identifiable with current techniques. Sometimes, the disease might occur years after the transplantation.

Long term functioning of organs: Many animals like pigs have a shorter lifespan than humans, meaning that their tissues age at a quicker rate. Hence, there is a question of whether the organ will function in the long term or not.

Medical Implications: Animal to human transplantation brings with it huge risks for the patient. Even well-matched human donor organs can be rejected after they are transplanted – and with animal organs, the danger is likely to be higher.

Ethical concerns: Activists say it is wrong to modify the genes of animals to make them more like humans. PETA has condemned the pig heart transplant. It said: “Animals aren’t tool-sheds to be raided but complex, intelligent beings. It would be better for them and healthier for humans to leave them alone and seek cures using modern science.”

What should be done?

Promote research in xenotransplantation: Instead of banning xenotransplantation, the government should study the potential, ensure adequate trials before approving the xenotransplantation procedures, considering the shortage of organs.

Promote organ donation: India should adopt the Spanish system of “presumed consent” where everyone, post-death, is considered a donor unless one has opted out of the process during his lifetime. This will help plug the Demand supply gap.

Curb organ trafficking: Organs should be made available to patients on the basis of medical need and not on the basis of financial or other considerations. Further, giving or receiving payment (including any other compensation or reward) for organs should be prohibited.

An organ may be removed from the body of an adult living donor for the purpose of transplantation if the donor gives free consent. The donor should be free of any influence and pressure and should be sufficiently informed about the risks, benefits, and consequences of consent.

An increasingly common cause of death and suffering is end stage failure of critical organs. Since new organs replace failing ones successfully, the world will continue to widen the net for sourcing them. But in humanity’s quest towards immortality, xenotransplantation shows that in good and bad ways, human lives depend not only on other humans but also on other species cohabiting the planet; all creatures big and small.

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