Трансплантация органов и тканей: методы и этические аспекты

Medical procedure in which an organ is removed from one body and placed in the body of a recipient

Organ transplantation is a medical procedure in which an organ is removed from one body and placed in the body of a recipient, to replace a damaged or missing organ. The donor and recipient may be at the same location, or organs may be transported from a donor site to another location. Organs and/or tissues that are transplanted within the same person's body are called autografts. Transplants that are recently performed between two subjects of the same species are called allografts. Allografts can either be from a living or cadaveric source. Organs that have been successfully transplanted include the heart, kidneys, liver, lungs, pancreas, intestine, thymus and uterus. Tissues include bones, tendons (both referred to as musculoskeletal grafts), corneae, skin, heart valves, nerves and veins. Worldwide, the kidneys are the most commonly transplanted organs, followed by the liver and then the heart. Corneae and musculoskeletal grafts are the most commonly transplanted tissues; these outnumber organ transplants by more than tenfold. Organ donors may be living, brain dead, or dead via circulatory death. Tissue may be recovered from donors who die of circulatory death, as well as of brain death – up to 24 hours past the cessation of heartbeat. Unlike organs, most tissues (with the exception of corneas) can be preserved and stored for up to five years, meaning they can be "banked". Transplantation raises a number of bioethical issues, including the definition of death, when and how consent should be given for an organ to be transplanted, and payment for organs for transplantation. Other ethical issues include transplantation tourism (medical tourism) and more broadly the socio economic context in which organ procurement or transplantation may occur. A particular problem is organ trafficking. There is also the ethical issue of not holding out false hope to patients.

Autografts are the transplant of tissue to the same person. Sometimes this is done with surplus tissue, tissue that can regenerate, or tissues more desperately needed elsewhere (examples include skin grafts, vein extraction for CABG, etc.). Sometimes an autograft is done to remove the tissue and then treat it or the person before returning it (examples include stem cell autograft and storing blood in advance of surgery). In a rotationplasty, a distal joint is used to replace a more proximal one; typically a foot or ankle joint is used to replace a knee joint. The person's foot is severed and reversed, the knee removed, and the tibia joined with the femur.

An allograft is a transplant of an organ or tissue between two genetically non identical members of the same species. Most human tissue and organ transplants are allografts. Due to the genetic difference between the organ and the recipient, the recipient's immune system will identify the organ as foreign and attempt to destroy it, causing transplant rejection. The risk of transplant rejection can be estimated by measuring the panel reactive antibody level.

An isograft is a subset of allograft in which organs or tissues are transplanted from a donor to a genetically identical recipient (such as an identical twin). Isografts are differentiated from other types of transplants because while they are anatomically identical to allografts, they do not trigger an immune response.

A xenograft is a transplant of organs or tissue from one species to another. An example is porcine heart valve transplant, which is quite common and successful. Another example is attempted piscine–primate (fish to non human primate) transplant of pancreatic islets. The latter research study was intended to pave the way for potential human use if successful. However, xenotransplantation is often an extremely dangerous type of transplant because of the increased risk of non functional compatibility, rejection, and disease carried in the tissue. In the opposite direction, attempts are being made to devise a way to transplant human fetal hearts and kidneys into animals for future transplantation into human patients to address the shortage of donor organs.

In people with cystic fibrosis (CF), where both lungs need to be replaced, it is a technically easier operation with a higher rate of success to replace both the heart and lungs of the recipient with those of the donor. As the recipient's original heart is usually healthy, it can then be transplanted into a second recipient in need of a heart transplant, thus making the person with CF a living heart donor. In a 2016 case at Stanford Medical Center, a woman who was needing a heart lung transplant had cystic fibrosis which had led to one lung expanding and the other shrinking, thereby displacing her heart. The second patient who in turn received her heart was a woman with right ventricular dysplasia which had led to a dangerously abnormal rhythm. The dual operations required three surgical teams, including one to remove the heart and lungs from a recently deceased initial donor. The two living recipients did well and had an opportunity to meet six weeks after their simultaneous operations. Another example of this situation occurs with a special form of liver transplant in which the recipient has familial amyloid polyneuropathy, a disease where the liver slowly produces a protein that damages other organs. The recipient's liver can then be transplanted into an older person for whom the effects of the disease will not necessarily contribute significantly to mortality. This term also refers to a series of living donor transplants in which one donor donates to the highest recipient on the waiting list and the transplant center utilizes that donation to facilitate multiple transplants. These other transplants are otherwise impossible due to blood type or antibody barriers to transplantation. The "Good Samaritan" kidney is transplanted into one of the other recipients, whose donor in turn donates his or her kidney to an unrelated recipient. This method allows all organ recipients to get a transplant even if their living donor is not a match for them. This further benefits people below any of these recipients on waiting lists, as they move closer to the top of the list for a deceased donor organ. Johns Hopkins Medical Center in Baltimore and Northwestern University's Northwestern Memorial Hospital have received significant attention for pioneering transplants of this kind. In February 2012, the last link in a record 60 person domino chain of 30 kidney transplants was completed. In May 2023, New York Presbyterian Morgan Stanley Children’s Hospital performed the first domino heart transplantation in a baby, eventually saving two baby girls.

Because very young children (generally under 12 months, but often as old as 24 months) do not have a well developed immune system, it is possible for them to receive organs from otherwise incompatible donors. This is known as ABO incompatible (ABOi) transplantation. Graft survival and people's mortality are approximately the same between ABOi and ABO compatible (ABOc) recipients. While focus has been on infant heart transplants, the principles generally apply to other forms of solid organ transplantation. United Network for Organ Sharing (UNOS) regulations allow for ABOi transplantation in children under two years of age if isohemagglutinin titers are 1:4 or below, and if there is no matching ABOc recipient. Studies have shown that the period under which a recipient may undergo ABOi transplantation may be prolonged by exposure to nonself A and B antigens. Furthermore, should the recipient (for example, type B positive with a type AB positive graft) require eventual retransplantation, the recipient may receive a new organ of either blood type. though this requires that the adult recipients have low levels of anti A or anti B antibodies.

Kidney transplantation is becoming increasingly common and is the preferred treatment for end stage renal failure. Liver transplantation is the only curative therapy for end stage liver disease, and the liver is the second most frequently transplanted solid organ. Pancreatic transplantation is a complex surgical procedure performed in patients with severe chronic diabetes, often in association with renal transplantation. Heart transplantation is increasingly performed in patients with end stage heart failure, most often related to ischemic and non ischemic cardiomyopathies.

The main complications are procedural complications, infection, acute rejection, cardiac allograft vasculopathy and malignancy. Organ donation is possible after cardiac death in some situations, primarily when the person is severely brain injured and not expected to survive without artificial breathing and mechanical support. Independent of any decision to donate, a person's next of kin may decide to end artificial support. If the person is expected to expire within a short period of time after support is withdrawn, arrangements can be made to withdraw that support in an operating room to allow quick recovery of the organs after circulatory death has occurred. Tissues may be recovered from donors who die of either brain or circulatory death. In general, tissues may be recovered from donors up to 24 hours past the cessation of heartbeat. In contrast to organs, most tissues (with the exception of corneas) can be preserved and stored for up to five years, meaning they can be "banked." Also, more than 60 grafts may be obtained from a single tissue donor. Because of these three factorsthe ability to recover from a non heart beating donor, the ability to bank tissue, and the number of grafts available from each donortissue transplants are much more common than organ transplants. The American Association of Tissue Banks estimates that more than one million tissue transplants take place in the United States each year.

In living donors, the donor remains alive and donates a renewable tissue, cell, or fluid (e. g., blood, skin), or donates an organ or part of an organ in which the remaining organ can regenerate or take on the workload of the rest of the organ (primarily single kidney donation, partial donation of liver, lung lobe, small bowel). Regenerative medicine may one day allow for laboratory grown organs, using person's own cells via stem cells, or healthy cells extracted from the failing organs.

Deceased donors (formerly cadaveric) are people who have been declared brain dead and whose organs are kept viable by ventilators or other mechanical mechanisms until they can be excised for transplantation. Apart from brainstem dead donors, who have formed the majority of deceased donors for the last 20 years, there is increasing use of after circulatory death donors (formerly non heart beating donors) to increase the potential pool of donors as demand for transplants continues to grow. Prior to the legal recognition of brain death in the 1980s, all deceased organ donors had died of circulatory death. These organs have inferior outcomes to organs from a brain dead donor. For instance, patients who underwent liver transplantation using donation after circulatory death allografts have been shown to have significantly lower graft survival than those from donation after brain death allografts due to biliary complications and primary nonfunction in liver transplantation. However, given the scarcity of suitable organs and the number of people who die waiting, any potentially suitable organ must be considered. Jurisdictions with medically assisted suicide may co ordinate organ donations from that source.

In most countries there is a shortage of suitable organs for transplantation. Countries often have formal systems in place to manage the process of determining who is an organ donor and in what order organ recipients receive available organs. The overwhelming majority of deceased donor organs in the United States are allocated by federal contract to the Organ Procurement and Transplantation Network, held since it was created by the Organ Transplant Act of 1984 by the United Network for Organ Sharing, or UNOS. (UNOS does not handle donor cornea tissue; corneal donor tissue is usually handled by multiple eye banks with guidance from the Eye Bank Association of America (EBAA) and Food and Drug Administration (FDA). Individual regional organ procurement organizations, all members of the Organ Procurement and Transplantation Network, are responsible for the identification of suitable donors and collection of the donated organs. UNOS then allocates organs based on the method considered most fair by the leadership in the field. The allocation methodology varies somewhat by organ, and changes periodically. For example, liver allocation is based partially on MELD score (Model of End Stage Liver Disease), an empirical score based on lab values indicative of the sickness of the person from liver disease. In 1984, the National Organ Transplant Act (NOTA) was passed; it gave way to the Organ Procurement and Transplantation Network, which maintains the organ registry and ensures equitable allocation of organs. The Scientific Registry of Transplant Recipients was also established to conduct ongoing studies into the evaluation and clinical status of organ transplants. In 2000 the Children's Health Act passed and required NOTA to consider special issues around pediatric patients and organ allocation. An example of "line jumping" occurred in 2003 at Duke University when doctors attempted to correct an initially incorrect transplant. An American teenager received a heart lung donation with the wrong blood type for her. She then received a second transplant even though she was then in such poor physical shape that she normally would not be considered a good candidate for a transplant. In an April 2008 article in The Guardian, Steven Tsui, the head of the transplant team at Papworth Hospital in the UK, is quoted in raising the ethical issue of not holding out false hope. He stated, "Conventionally we would say if people's life expectancy was a year or less we would consider them a candidate for a heart transplant. But we also have to manage expectations. If we know that in an average year we will do 30 heart transplants, there is no point putting 60 people on our waiting list, because we know half of them will die and it's not right to give them false hope." Experiencing somewhat increased popularity, but still very rare, is directed or targeted donation, in which the family of a deceased donor (often honoring the wishes of the deceased) requests an organ be given to a specific person, subverting the allocation system. In the United States, there are various lengths of waiting times due to the different availabilities of organs in different UNOS regions. In other countries such as the UK, only medical factors and the position on the waiting list can affect who receives the organ. One of the more publicized cases of this type was the 1994 Chester and Patti Szuber transplant. This was the first time that a parent had received a heart donated by one of their own children. Although the decision to accept the heart from his recently killed child was not an easy decision, the Szuber family agreed that giving Patti's heart to her father would have been something that she would have wanted. Access to organ transplantation is one reason for the growth of medical tourism.

Living related donors donate to family members or friends in whom they have an emotional investment. The risk of surgery is offset by the psychological benefit of not losing someone related to them, or not seeing them suffer the ill effects of waiting on a list.

A "paired exchange" is a technique of matching willing living donors to compatible recipients using serotyping. For example, a spouse may be willing to donate a kidney to their partner but cannot since there is not a biological match. The willing spouse's kidney is donated to a matching recipient who also has an incompatible but willing spouse. The second donor must match the first recipient to complete the pair exchange. Typically the surgeries are scheduled simultaneously in case one of the donors decides to back out and the couples are kept anonymous from each other until after the transplant. Paired donor exchange, led by work in the New England Program for Kidney Exchange as well as at Johns Hopkins University and the Ohio organ procurement organizations, may more efficiently allocate organs and lead to more transplants. Paired exchange programs were popularized in the New England Journal of Medicine article "Ethics of a paired kidney exchange program" in 1997 by L. F. Ross. It was also proposed by Felix T. Rapport in 1986 as part of his initial proposals for live donor transplants "The case for a living emotionally related international kidney donor exchange registry" in Transplant Proceedings. A paired exchange is the simplest case of a much larger exchange registry program where willing donors are matched with any number of compatible recipients. Transplant exchange programs have been suggested as early as 1970: "A cooperative kidney typing and exchange program." The first pair exchange transplant in the US was in 2001 at Johns Hopkins Hospital. The first complex multihospital kidney exchange involving 12 people was performed in February 2009 by The Johns Hopkins Hospital, Barnes Jewish Hospital in St. Louis and Integris Baptist Medical Center in Oklahoma City. Another 12 person multihospital kidney exchange was performed four weeks later by Saint Barnabas Medical Center in Livingston, New Jersey, Newark Beth Israel Medical Center and New York Presbyterian Hospital. Surgical teams led by Johns Hopkins continue to pioneer this field with more complex chains of exchange, such as an eight way multihospital kidney exchange. In December 2009, a 13 organ 13 recipient matched kidney exchange took place, coordinated through Georgetown University Hospital and Washington Hospital Center, Washington, DC.

Good Samaritan or "altruistic" donation is giving a donation to someone that has no prior affiliation with the donor. The idea of altruistic donation is to give with no interest of personal gain, it is out of pure selflessness. On the other hand, the current allocation system does not assess a donor's motive, so altruistic donation is not a requirement. Some people choose to do this out of a personal need to donate. Some donate to the next person on the list; others use some method of choosing a recipient based on criteria important to them. Websites are being developed that facilitate such donation. Over half of the members of the Jesus Christians, an Australian religious group, have donated kidneys in such a fashion.

There have been concerns that certain authorities are harvesting organs from people deemed undesirable, such as prison populations. The World Medical Association stated that prisoners and other individuals in custody are not in a position to give consent freely, and therefore their organs must not be used for transplantation. According to former Chinese Deputy Minister of Health, Huang Jiefu, the practice of transplanting organs from executed prisoners is still occurring as of 2017. World Journal reported Huang had admitted approximately 95% of all organs used for transplantation are from executed prisoners. stated, "the source of 41,500 transplants for the six year period 2000 to 2005 is unexplained" and "we believe that there has been and continues today to be large scale organ seizures from unwilling Falun Gong practitioners". However 2016 reports updated the death toll of the 15 year period since the persecution of Falun Gong began putting the death toll at 150,000 to 1.5 million. In December 2006, after not getting assurances from the Chinese government about allegations relating to Chinese prisoners, the two major organ transplant hospitals in Queensland, Australia stopped transplantation training for Chinese surgeons and banned joint research programs into organ transplantation with China. In May 2008, two United Nations Special Rapporteurs reiterated their requests for "the Chinese government to fully explain the allegation of taking vital organs from Falun Gong practitioners and the source of organs for the sudden increase in organ transplants that has been going on in China since the year 2000". People in other parts of the world are responding to this availability of organs, and a number of individuals (including US and Japanese citizens) have elected to travel to China or India as medical tourists to receive organ transplants which may have been sourced in what might be considered elsewhere to be unethical manner.

Successful human allotransplants have a relatively long history of operative skills that were present long before the necessities for post operative survival were discovered. Rejection and the side effects of preventing rejection (especially infection and nephropathy) were, are, and may always be the key problem. Several apocryphal accounts of transplants exist well prior to the scientific understanding and advancements that would be necessary for them to have actually occurred. The Chinese physician Pien Chi'ao reportedly exchanged hearts between a man of strong spirit but weak will with one of a man of weak spirit but strong will in an attempt to achieve balance in each man. Roman Catholic accounts report the 3rd century saints Damian and Cosmas as replacing the gangrenous or cancerous leg of the Roman deacon Justinian with the leg of a recently deceased Ethiopian. Most accounts have the saints performing the transplant in the 4th century, many decades after their deaths; some accounts have them only instructing living surgeons who performed the procedure. The more likely accounts of early transplants deal with skin transplantation. The first reasonable account is of the Indian surgeon Sushruta in the 2nd century BC, who used autografted skin transplantation in nose reconstruction, a rhinoplasty. Success or failure of these procedures is not well documented. Centuries later, the Italian surgeon Gasparo Tagliacozzi performed successful skin autografts; he also failed consistently with allografts, offering the first suggestion of rejection centuries before that mechanism could possibly be understood. He attributed it to the "force and power of individuality" in his 1596 work De Curtorum Chirurgia per Insitionem. The first successful corneal allograft transplant was performed in 1837 in a gazelle model; the first successful human corneal transplant, a keratoplastic operation, was performed by Eduard Zirm at Olomouc Eye Clinic, now in the Czech Republic, in 1905. The first transplant in the modern sense – the implantation of organ tissue in order to replace an organ function – was a thyroid transplant in 1883. It was performed by the Swiss surgeon and later Nobel laureate Theodor Kocher. In the preceding decades Kocher had perfected the removal of excess thyroid tissue in cases of goiter to an extent that he was able to remove the whole organ without the person dying from the operation. Kocher carried out the total removal of the organ in some cases as a measure to prevent recurrent goiter. By 1883, the surgeon noticed that the complete removal of the organ leads to a complex of particular symptoms that we today have learned to associate with a lack of thyroid hormone. Kocher reversed these symptoms by implanting thyroid tissue to these people and thus performed the first organ transplant. In the following years Kocher and other surgeons used thyroid transplantation also to treat thyroid deficiency that appeared spontaneously, without a preceding organ removal. Thyroid transplantation became the model for a whole new therapeutic strategy: organ transplantation. After the example of the thyroid, other organs were transplanted in the decades around 1900. Some of these transplants were done in animals for purposes of research, where organ removal and transplantation became a successful strategy of investigating the function of organs. Kocher was awarded his Nobel Prize in 1909 for the discovery of the function of the thyroid gland. At the same time, organs were also transplanted for treating diseases in humans. The thyroid gland became the model for transplants of adrenal and parathyroid glands, pancreas, ovary, testicles and kidney. By 1900, the idea that one can successfully treat internal diseases by replacing a failed organ through transplantation had been generally accepted. Pioneering work in the surgical technique of transplantation was made in the early 1900s by the French surgeon Alexis Carrel, with Charles Guthrie, with the transplantation of arteries or veins. Their skillful anastomosis operations and the new suturing techniques laid the groundwork for later transplant surgery and won Carrel the 1912 Nobel Prize in Physiology or Medicine. From 1902, Carrel performed transplant experiments on dogs. Surgically successful in moving kidneys, hearts, and spleens, he was one of the first to identify the problem of rejection, which remained insurmountable for decades. The discovery of transplant immunity by the German surgeon Georg Schöne, various strategies of matching donor and recipient, and the use of different agents for immune suppression did not result in substantial improvement so that organ transplantation was largely abandoned after WWI. The first attempted human deceased donor transplant was performed by the Ukrainian surgeon Yurii Voronoy in the 1930s; but failed due to ischemia. Joseph Murray and J. Hartwell Harrison performed the first successful transplant, a kidney transplant between identical twins, in 1954, because no immunosuppression was necessary for genetically identical individuals. In the late 1940s British surgeon Peter Medawar, working for the National Institute for Medical Research, improved the understanding of rejection. Identifying the immune reactions in 1951, Medawar suggested that immunosuppressive drugs could be used. Cortisone had been recently discovered and the more effective azathioprine was identified in 1959, but it was not until the discovery of cyclosporine in 1970 that transplant surgery found a sufficiently powerful immunosuppressive. There was a successful deceased donor lung transplant into an emphysema and lung cancer patient in June 1963 by James Hardy at the University of Mississippi Medical Center in Jackson, Mississippi. The patient John Russell survived for eighteen days before dying of kidney failure. Thomas Starzl of Denver attempted a liver transplant in the same year, but he was not successful until 1967. In the early 1960s and prior to long term dialysis becoming available, Keith Reemtsma and his colleagues at Tulane University in New Orleans attempted transplants of chimpanzee kidneys into 13 human patients. Most of these patients only lived one to two months. However, in 1964, a 23 year old woman lived for nine months and even returned to her job as a school teacher until she suddenly collapsed and died. It was assumed that she died from an acute electrolyte disturbance. At autopsy, the kidneys had not been rejected nor was there any other obvious cause of death. One source states this patient died from pneumonia. Tom Starzl and his team in Colorado used baboon kidneys with six human patients who lived one or two months, but with no longer term survivors. Others in the United States and France had limited experiences. The heart was a major prize for transplant surgeons. But over and above rejection issues, the heart deteriorates within minutes of death, so any operation would have to be performed at great speed. The development of the heart lung machine was also needed. Lung pioneer James Hardy was prepared to attempt a human heart transplant in 1964, but when a premature failure of comatose Boyd Rush's heart caught Hardy with no human donor, he used a chimpanzee heart, which beat in his patient's chest for approximately one hour and then failed. The first partial success was achieved on 3 December 1967, when Christiaan Barnard of Cape Town, South Africa, performed the world's first human to human heart transplant with patient Louis Washkansky as the recipient. Washkansky survived for eighteen days amid what many saw as a distasteful publicity circus. The media interest prompted a spate of heart transplants. Over a hundred were performed in 1968–1969, but almost all the people died within 60 days. Barnard's second patient, Philip Blaiberg, lived for 19 months. It was the advent of cyclosporine that altered transplants from research surgery to life saving treatment. In 1968 surgical pioneer Denton Cooley performed 17 transplants, including the first heart lung transplant. Fourteen of his patients were dead within six months. By 1984 two thirds of all heart transplant patients survived for five years or more. With organ transplants becoming commonplace, limited only by donors, surgeons moved on to riskier fields, including multiple organ transplants on humans and whole body transplant research on animals. On 9 March 1981, the first successful heart lung transplant took place at Stanford University Hospital. The head surgeon, Bruce Reitz, credited the patient's recovery to cyclosporine. As the rising success rate of transplants and modern immunosuppression make transplants more common, the need for more organs has become critical. Transplants from living donors, especially relatives, have become increasingly common. Additionally, there is substantive research into xenotransplantation, or transgenic organs; although these forms of transplant are not yet being used in humans, clinical trials involving the use of specific cell types have been conducted with promising results, such as using porcine islets of Langerhans to treat type 1 diabetes. However, there are still many problems that would need to be solved before they would be feasible options in people requiring transplants. Recently, researchers have been looking into means of reducing the general burden of immunosuppression. Common approaches include avoidance of steroids, reduced exposure to calcineurin inhibitors, and other means of weaning drugs based on patient outcome and function. While short term outcomes appear promising, long term outcomes are still unknown, and in general, reduced immunosuppression increases the risk of rejection and decreases the risk of infection. The risk of early rejection is increased if corticosteroid immunosuppression are avoided or withdrawn after renal transplantation. Many other new drugs are under development for transplantation. The emerging field of regenerative medicine promises to solve the problem of organ transplant rejection by regrowing organs in the lab, using person's own cells (stem cells or healthy cells extracted from the donor site).

Since 2000, there have been approximately 2,200 lung transplants performed each year worldwide. From 2000 to 2006, the median survival period for lung transplant patients has been 5.5 years.

In China, a kidney transplant operation runs for around $70,000, liver for $160,000, and heart for $120,000. It is essential that the HLA complexes of both the donor and recipient be as closely matched as possible to prevent graft rejection. In November 2007, the CDC reported the first ever case of HIV and Hepatitis C being simultaneously transferred through an organ transplant. The donor was a 38 year old male, considered "high risk" by donation organizations, and his organs transmitted HIV and Hepatitis C to four organ recipients. Experts say that the reason the diseases did not show up on screening tests is probably because they were contracted within three weeks before the donor's death, so antibodies would not have existed in high enough numbers to detect. The crisis has caused many to call for more sensitive screening tests, which could pick up antibodies sooner. Currently, the screens cannot detect the small number of antibodies produced in HIV infections within the last 90 days or Hepatitis C infections within the last 18–21 days before a donation is made. Nucleic acid testing is now being done by many organ procurement organizations and is able to detect HIV and hepatitis C directly within seven to ten days of exposure to the virus.

The existence and distribution of organ transplantation procedures in developing countries, while almost always beneficial to those receiving them, raise many ethical concerns. Both the source and method of obtaining the organ to transplant are major ethical issues to consider, as well as the notion of distributive justice. The World Health Organization argues that transplantations promote health, but the notion of "transplantation tourism" has the potential to violate human rights or exploit the poor, to have unintended health consequences, and to provide unequal access to services, all of which ultimately may cause harm. Regardless of the "gift of life", in the context of developing countries, this might be coercive. The practice of coercion could be considered exploitative of the poor population, violating basic human rights according to Articles 3 and 4 of the Universal Declaration of Human Rights. There is also a powerful opposing view, that trade in organs, if properly and effectively regulated to ensure that the seller is fully informed of all the consequences of donation, is a mutually beneficial transaction between two consenting adults, and that prohibiting it would itself be a violation of Articles 3 and 29 of the Universal Declaration of Human Rights. Even within developed countries there is concern that enthusiasm for increasing the supply of organs may trample on respect for the right to life. The question is made even more complicated by the fact that the "irreversibility" criterion for legal death cannot be adequately defined and can easily change with changing technology.

Surgeons, notably Paolo Macchiarini, in Sweden performed the first implantation of a synthetic trachea in July 2011, for a 36 year old patient who had cancer. Stem cells taken from the patient's hip were treated with growth factors and incubated on a plastic replica of his natural trachea. According to information uncovered by the Swedish documentary "Dokument Inifrån: Experimenten" (Swedish: "Documents from the Inside: The Experiments") the patient, Andemariam went on to develop an increasingly terrible and eventually bloody cough to dying, incubated, in the hospital. At that point, determined by autopsy, 90% of the synthetic windpipe had come loose. He allegedly made several trips to see Macchiarini for his complications, and at one point had surgery again to have his synthetic windpipe replaced, but Macchiarini was notoriously difficult to get an appointment with. According to the autopsy, the old synthetic windpipe did not appear to have been replaced. Macchiarini's academic credentials have been called into question and he has recently been accused of alleged research misconduct. Left ventricular assist devices are often used as a "bridge" to provide additional time while a patient waits for a transplant. For example, former US vice president Dick Cheney had such a device implanted in 2010 and then 20 months later received a heart transplant in 2012. In year 2012, about 3,000 ventricular assist devices were inserted in the United States, as compared to approximately 2,500 heart transplants. The use of airbags in cars as well as greater use of helmets by bicyclists and skiers has reduced the number of persons with fatal head injuries, which is a common source of donors hearts.

An early stage medical laboratory and research company, called Organovo, designs and develops functional, three dimensional human tissue for medical research and therapeutic applications. The company utilizes its NovoGen MMX Bioprinter for 3D bioprinting. Organovo anticipates that the bioprinting of human tissues will accelerate the preclinical drug testing and discovery process, enabling treatments to be created more quickly and at lower cost. Additionally, Organovo has long term expectations that this technology could be suitable for surgical therapy and transplantation. A further area of active research is concerned with improving and assessing organs during their preservation. Various techniques have emerged which show great promise, most of which involve perfusing the organ under either hypothermic (4–10 °C) or normothermic (37 °C) conditions. All of these add additional cost and logistical complexity to the organ retrieval, preservation and transplant process, but early results suggest it may well be worth it. Hypothermic perfusion is in clinical use for transplantation of kidneys and liver whilst normothermic perfusion has been used effectively in the heart, lung, liver and, less so, in the kidney. Another area of research being explored is the use of genetically engineered animals for transplants. Similar to human organ donors, scientists have developed a genetically engineered pig with the aim of reducing rejection to pig organs by human patients. This is currently at the basic research stage, but shows great promise in alleviating the long waiting lists for organ transplants and the number of people in need of transplants outweighs the amount of organs donated. Trials are being done to prevent the pig organ transplant to enter a clinical trial phase until the potential disease transfer from pigs to humans can be safely and satisfactorily managed (Isola & Gordon, 1991).