Present Status and Future Outlook
In the past three decades
transplantation has moved from an experimental procedure to clinical therapy.
Kidney grafting has been the most successful
organ Transplant thus far, because patients with kidney failure can be kept in good health by regular hemodialysis (see kidney, artificial). For other
organs no such equivalent luxury exists. Numerous kinds of transplant operations are performed, including corneal transplants, heart, heart-lung, single-lung, liver, bone-marrow, skin, and pancreas transferrals. Corneal tranplants have a very low rate of rejection, because the cornea has few blood vessels, limiting the exposure of the new cornea to cells that would trigger an immunological reaction. Multiple-organ
transplants are becoming more frequent. With the advent of cyclosporine the success rate for many of these operations has increased as it did in liver transplants, but others remain notably difficult. In 1998, French physicians attempted the first limb transplant in over 30 years. They attached the hand and forearm from a brain-dead patient to the arm of a man who lost his hand in an accident, using the same microsurgery techniques that are used to reattach limbs severed in accidents.
The one-year graft survival rate is generally close to 80% for most organs. Although this is a major achievement, the ten-year graft survival rate is about 40%; more research on
tissue typing and immunosuppression is needed. The most severe bottleneck to transplantation today is the supply of donor organs. Although 25,000 patients are on dialysis waiting for a kidney transplant in the United States, only about 8,000 receive a new kidney each year. Living donors, often family members, can give one kidney if there is a tissue match. Since a healthy liver can regenerate itself, some surgeons now remove part of a liver from living donors (usually parents) for transplantation into children with fatal liver disease.
Development of artificial organs would make transplantation obsolete, but even the artificial kidney is no match for nature's kidney with respect to function and ease of operation. Transplantation of cells, such as the islets of the pancreas in the cure of diabetes, is a major possibility within the first decade of the 21st century. A great deal of research is now under way to determine the feasibility of using animal organs, but matching tissue remains a major obstacle.
Ethical Issues
The increased success of organ transplantation has raised many ethical issues. The methods of allocating organs have been questioned. Should very ill patients receive second and third transplants, or should the organs go to another person? Organ donation presently does not involve money for the donor, but there is also great concern about the development of an organ black market, with people who need money donating, and people who have money ignoring the allocation list. Although there is continuing research on the use of animal organs, many people question whether animals should be used in this manner. The possible use of aborted human fetuses as a source for tissues such as pancreas or brain has ignited great controversy.
Parents of anencephalic infants with minimal brain activity have expressed a desire to donate the child's organs but the legal definition of brain death has prevented these transplants. In other notable cases, parents have provided a very ill child part of a lung or liver, and other families have had additional children to serve as a sibling donor of bone marrow in one case, and umbilical-cord stem cells in another case, for a sick older child. Very few developments in medicine have brought so many new ethical dilemmas.
More abstracts about the TRANSPLANTATION-PRESENT STATUS FUTURE OUTLOOK AND ETHICAL ISSUES