Organ transplant


An organ transplant is the transplantation of an organ (or part of one) from
one body to another, for the purpose of replacing the recipient's damaged or
failing organ with a working one from the donor.

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 organ donor either has another of the same organ (such as lungs
or kidneys), or has been declared brain dead.

Organs that can currently be transplanted include:

   * Liver
   * Kidney
   * Lung
   * Heart
   * Corneas
   * Skin (a skin graft)
   * Blood vessels

The heart and lungs are sometimes transplanted together, in a heart-lung
transplant.

Organ transplants that can not be performed today include

   * Head transplant or Whole-body transplant
   * cardia or Lower Esophageal Sphincter(LES) for achalasia.

History

Successful inter-human transplants 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 occured 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 perofrmed - re-attaching a severed limb
and restoring (limited) functioning and feeling.

The first successful cornea transplant, a keroplastic 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 in 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, he 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 in December 1967 by
Christiaan Barnard in Cape Town, Louis Washkansky survived for eighteen days
amid a distasteful publicity circus. The media interest prompted a spate of
heart transplants, over a hundred were performed in 1968-69, almost all the
patients died within sixty days.

As mentioned, it was the advent of cyclosporine that altered transplants
from research surgery to live-saving treatment. In 1968 surgical pioneer
Denton Cooley performed seventeen transplants, 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 (first successful heart-lung in 1981)
and whole-body transplant research on animals. Other researchers moved onto
the use of artifical, animal or trans-genic organs.