Diseases & Conditions
Transplantation of Other Organs
Skin grafts can be used in people who have lost large areas of skin—for example, because of extensive burns. Skin grafting is most successful when healthy skin is removed from one part of the body and grafted to another part. When such grafting is not possible, skin from a donor or even from animals (such as pigs) can be used as a temporary measure. Such grafts last only a short time, but they can provide temporary protection until normal skin grows to replace them. The amount of skin available for grafting may be increased by growing small pieces of the person's skin in a tissue culture or by making many tiny cuts in the grafted skin, so that it can be stretched to cover a much larger area.
Cartilage may be transplanted successfully without the use of immunosuppressants. The body's immune system attacks transplanted cartilage much less vigorously than other tissues. In children, cartilage is usually used to repair defects in the ears or nose. In adults, it can be used to repair joints damaged by injury and occasionally by arthritis.
Corneas, the transparent domes on the surface of the eyes, can usually be transplanted successfully without the use of immunosuppressants.
Corneal Transplants and Why They Usually Work
Corneal transplantation is a common and highly successful type of transplantation. A scarred or cloudy cornea can be replaced with a clear, healthy one. Doctors using a surgical microscope carry out the procedure in about 1 hour. Donated corneas come from people who have recently died. A general or local anesthetic is used. The donated cornea is cut to the right size, the damaged cornea is removed, and the donated cornea is sewn in place. The recipient usually stays in the hospital 1 or 2 nights but may go home the same day.
A cornea is rarely rejected because it does not have its own blood supply. It receives oxygen and other nutrients from nearby tissues and fluid. The components of the immune system that initiate rejection in response to a foreign substance—certain white blood cells and antibodies—are carried in the bloodstream. Thus, these cells and antibodies do not reach the transplanted cornea, do not encounter the foreign tissue there, and do not initiate rejection. Tissues with a rich blood supply are much more likely to be rejected.
Bone from one part of the body can be used to replace bone in another part. Bone transplanted from one person to another survives only a short time. However, it stimulates growth of new bone, stabilizes the area until new bone can form, and provides a framework for new bone to fill in.
Transplantation of the small intestine may be used when the intestine does not absorb nutrients because of a disorder or has had to be removed because of a disorder or injury, and other forms of nutrition have failed. Intestinal transplants are particularly prone to both infection and rejection, and less than 80% last for more than 1 year. Because the small intestine contains a large amount of lymphatic tissue, the new intestinal tissue may produce cells that attack the recipient's cells, causing graft-versus-host disease.
Parkinson's disease can be treated by transplanting tissue from a person's adrenal glands to that person's brain. Alternatively, brain tissue from aborted fetuses can be used. Both procedures can relieve symptoms. However, the ethics of using tissue from aborted fetuses is controversial.
Thymus glands from aborted or miscarried fetuses can be transplanted into children who are born without a thymus gland (a disorder called DiGeorge anomaly). When the thymus gland is missing, the immune system is impaired, because white blood cells, which are a vital part of the immune system's defense against foreign substances, mature in the thymus gland. Transplantation of a thymus gland restores the impaired immune system in these children. However, the new thymus may produce cells that attack the recipient's cells, causing graft-versus-host-disease.
Rarely, transplantation of limbs and faces from one person to another has been attempted, but this technique is experimental.
Reattaching a Body Part
If fingers, hands, and arms are relatively undamaged after being severed from the body, they can sometimes be reattached successfully. Reattachment of legs is less successful. The severed part is kept clean and is put in a plastic bag and placed on ice until it can be used. Prompt reattachment is crucial so that the blood supply to the severed part can be restored.
Last full review/revision September 2008 by Martin Hertl, MD, PhD; James F. Markmann, MD, PhD; Paul S. Russell, MD; Heidi Yeh, MD
Source: The Merck Manual Home Edition