In January 2022, in a medical first, doctors transplanted a pig heart into a patient to save his life in the US. The patient was deemed ineligible for a conventional heart transplant or an artificial heart by leading transplant centres after a review of his medical records.
In this article, you can learn all about the process of xenotransplantation for the IAS exam. Latest developments in science and technology are important for UPSC.
Xenotransplantation
Xenotransplantation is any procedure that involves the transplantation, implantation or infusion into a human recipient of either (a) live cells, tissues, or organs from a nonhuman animal source, or (b) human body fluids, cells, tissues or organs that have had ex vivo contact with live nonhuman animal cells, tissues or organs.
- One of the biggest obstacles to transplantation is organ rejection. In the above case, scientists have addressed the problem by genetically altering pigs’ organs. The donor pig underwent 10 genetic modifications, by which the genes responsible for the rapid rejection of foreign organs by the human body were inactivated or knocked out.
History of Xenotransplantation
Xenotransplantation was first tried in humans in the 1980s. American Baby Fae who was born with a congenital heart defect had received a baboon heart in 1984. The surgery was successful, but the baby died within a month of the transplant after it was rejected by her body’s immune system.
- Notably, pig heart valves have been used for replacing damaged valves in humans for over 50 years now.
- Also some patients with diabetes have received porcine pancreas cells.
Why pigs are most used for xenotransplantation?
- Pigs are increasingly becoming popular candidates for organ transplantation.
- Pigs offer advantages over primates for organ procurements, because they are easier to raise and achieve adult human size in six months. Also pigs have large litters. Hence pigs could provide an unlimited supply of organs, tissues, and cells.
- 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.
- Also porcine components are more tuned for genetic engineering. From a scientific viewpoint, pigs are genetically modifiable to reduce the chances of rejection by the human body.
- Pigs are produced for food, so using them for organs raises fewer ethical concerns.
Xenotransplantation Significance
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. Xenotransplantation, if found compatible in the long run, could help provide an alternative supply of organs to those with life-threatening diseases. This development would help solve the global organ shortage.
- The ample availability of organs will help overcome issues of organ trafficking and ethical issues concerning the practice of commercial transactions between a potential recipient and a paid living donor.
- Recent evidence has suggested that transplantation of cells and tissues may be therapeutic for certain diseases such as neurodegenerative disorders and diabetes, where, again human materials are not usually available. Certain procedures, some of which are being investigated in early clinical trials, aim to use cells or tissues from other species to treat life-threatening and debilitating illnesses such as cancer, diabetes, liver failure and Parkinson’s disease.
Xenotransplantation Issues
In this section, some of the issues regarding the process of xenotransplantation are discussed.
- Xenotransplantation raises several medical challenges.
- Animal to human transplantation brings with it huge risks for the patient in the form of immunological rejection. This can result in the immediate death of the recipient in some cases. Even well-matched human donor organs can be rejected after they are transplanted – and with animal organs, the danger is likely to be higher.
- 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.
- Disease transmission (zoonosis) remains a major concern in terms of public health. The use of xenotransplantation raises concerns regarding the potential infection of recipients with both recognized and unrecognized infectious agents and the possible subsequent transmission to their close contacts and into the general human population.
- Apart from the medical challenge, xenotransplantation raises many ethical issues as well.
- Similar to objections to animal testing, animal rights activists have also objected to xenotransplantation on ethical grounds. Animal rights groups strongly oppose killing animals to harvest their organs for human use.
- Permanent alteration to the genetic code of animals are also causes for concern. Activists say it is wrong to modify the genes of animals to make them more like humans.
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