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Organ transplant

From Academic Kids

An organ transplant is the transplantation of a whole or partial organ from one body to another, for the purpose of replacing the recipient's damaged or failing organ with a working one from the donor. Organ donors can be living, or cadaveric (dead).

Contents

Origin of the transplant

Blood transfusion and bone marrow transplants are special cases of a transplant where the transplanted part of the body is renewable; in other cases, the living organ donor either has another of the same organ (such as kidneys) or can donate part of an organ (such as split-liver, segmental pancreas and small intestine transplants).

Apart from brain-stem dead donors, who have formed the majority of cadaveric donors for the last twenty years, there is increasing use of non-heart beating donors to increase the potential pool of donors as demand for transplants continues to grow.

Types of transplants

Solitary transplants

Organs and tissues that can currently be transplanted include:

Combined transplants

The heart and lungs are sometimes transplanted together, in a heart-lung transplant. This operation is usually performed for cystic fibrosis as both lungs need to be replaced and it is a technically easier operation to replace the heart and lungs en bloc. As the recipient's native heart is usually healthy, this can then itself be transplanted into someone needing a heart transplant; this is called a domino transplant. That term is also used for a special form of liver transplant, in which the recipient suffers from familial amyloidotic polyneuropathy in which the liver (slowly) produces a protein that damages other organs; their liver can be transplanted into an older patient who is likely to die from other causes before a problem arises[1] (http://www.mayoclinic.org/news2003-sct/1622.html).

Most pancreas transplants are performed for diabetes mellitus with chronic renal failure due to diabetic nephropathy and are transplanted together with a kidney. Diabetes alone does not typically justify a transplant.

Newer types

Hand transplant operations have been performed since 1998. The yield is not good enough to recommend this on a routine basis to those with mutilating injuries or congenital malformations. On the 14th of January 2004, the team of Professor Jean-Michel Dubernard (Edouard-Herriot hospital, France) declared a five-year old transplantion of both hands a success[2] (http://www.lemonde.fr/web/article/0,1-0%402-3226,36-394244,0.html). The lessons learned in this case, and the 26 other which occurred between 2000 and 2005, might open the way for more common transplants of such organs as hands, face, kidney or larynx.

Transplants that are nearly feasible today include:

Organ transplants that can not be performed today include:

History

Successful inter-human allotransplants have a relatively long history, the operative skills were present long before the necessities for post-operative survival were discovered. Rejection was, is, and may always be the key problem.

The third century saints Damian and Cosmas are recorded as performing the first medical transplant - replacing the gangrenous leg of a white man with the leg of a dead Moor. Less miraculous was the work of French surgeon Alexis Carrel, in the 1900s, with the transplantation of arteries or veins. His skillful anastomosis operations, the new suturing techniques, laid the ground for later transplant surgery. 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.

Autotransplants, transfer of material on the same patient, was successfully demonstrated by Jean Casimir Guyon with skin in 1869. Slightly later, Jacques Reverdin used a similar technique to aid wound healing. Major steps in skin transplants occurred during WW I, notably in the work of Harold Gillies at Aldershot. Among his advances was the tubed pedicle graft, maintaining a flesh connection from the donor site until the graft established its own blood flow. Gillies' assistant, Archibald McIndoe, carried on the work into WW II as reconstructive surgery. In 1962 the first successful replantation surgery was performed - re-attaching a severed limb and restoring (limited) functioning and feeling.

The first successful cornea transplant, a keratoplastic operation, was performed by Eduard Zirm in Austria in 1906; for all other transplants rejection seemed an insurmountable problem. In the late 1940s 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.

The first successful human organ transplant was the kidney on 23 December 1954 in Boston by Joseph Murray and J. Hartwell Harrison. The kidney was the easiest organ to transplant, tissue-typing was simple, the organ was relatively easy to remove and implant, live donors could be used without difficulty, and in the event of failure kidney dialysis was available from the 1940s. Tissue-typing was essential to the success, early attempts in the 1950s on sufferers from Bright's disease had been very unsuccessful. The 1954 transplant was between identical twins.

The success with the kidney led to attempts with other organs. There was a successful cadaveric lung transplant into a lung cancer sufferer in June 1963 by James Hardy in Jackson, Mississippi. The patient survived for eighteen days before dying of kidney failure. Thomas Starzl of Denver attempted a liver transplant in the same year, but was not successful until 1967.

The heart was a major prize for transplant surgeons. But, as well as 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 attempted a human heart transplant in 1964, but a premature failure of the recipient's heart caught Hardy with no human donor, he used a chimpanzee heart which failed very quickly. The first success was achieved December 3rd 1967 by Christiaan Barnard in Cape Town, South Africa. Louis Washkansky, the recipient, 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 1968-69, but almost all the patients died within sixty days. Barnard's second patient, Philip Blaiberg, lived for 19 months.

As mentioned, it was the advent of cyclosporine that altered transplants from research surgery to life-saving treatment. In 1968 surgical pioneer Denton Cooley performed seventeen 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 onto more risky fields, multiple organ transplants on humans and whole-body transplant research on animals. On March 9th 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-A.

The latest record transplant operation of eight organs, the liver, stomach, pancreas, small and large intestine, spleen, and two kidneys, was performed in the USA in March 2004. This patient, a 6 month old baby, died 1 month after the operation.

With organ shortages a real problem in many fields, as well as the continuous problem of incompatibility and rejection, there is substantive research into xenotransplantation or transgenic organs. These forms of transplant are not yet being used in humans, and there are still many problems that would need to be solved before they would be feasible options in patients requiring transplants.

Organ black market

As the need for ready to transplant organs worldwide increases, so does the reality of the illicit organ market. Each year, hundreds of impoverished people sell their kidneys to later be used in illegal transplants. The size and scope of this current problem has yet to be fully understood or realized, but European officials have been working hard in Europe to ensure the closure of the organ black market.

See also

Reference

External link

fr:Greffe it:Trapianto d'organi ja:生体移植 no:Transplantasjon pl:Przeszczepianie narzdw pt:Transplantao de rgos sk:Transplantcia sv:Transplantation he:השתלת איברים

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