Introduction
In organ transplantation, a diseased organ of a patient is replaced by the same organ from a donor. This organ donor is usually recently deceased and has agreed to the removal of his organs if his death can be proven beyond doubt. Living people can also be considered as donors if a special relationship such as kinship or partnership exists.
However, only one organ in a couple (such as a kidney) or one organ segment (such as a piece of liver) may be donated. There is of course a risk for the donor. An organ transplantation is usually preceded by a lengthy process.
First, it must be determined that the patient has no chance of complete recovery and that the organ is irreversibly damaged. Then the patient is put on a long transplantation list, on which all future recipients of a new organ are listed. It is not uncommon for the waiting period to be too long and for the patient to die before the operation.
If it comes to the fortunate circumstance that a suitable organ is found for a patient, the following procedures must be carried out quickly. The organ must be removed from the organ donor as quickly as possible and transported to the recipient in a cool place. Once it arrives, the damaged organ is removed and the new organ is inserted in the same procedure. To ensure that all processes run as quickly as possible, all people who are willing to be organ donors after their death should carry an organ donor card with them. Many potentially life-saving organs cannot be removed due to legal uncertainties.
Risks of organ transplantation
The risks involved in organ transplantation can be many and varied and are mainly concentrated on the operation performed. The replacement of an organ means that large vessels have to be interrupted. If these vessels are damaged, the patient can lose large amounts of blood within a very short time and may die from the blood loss.
Otherwise, all general risks that can occur during operations, especially those of a larger nature, such as complications during anesthesia, apply. Especially when transplanting a heart or lung, the human body is strained by the connection to a heart-lung machine. The transplanted organ can also cause difficulties.
If it is not transplanted quickly enough or not connected to the blood supply efficiently enough, it may not be possible to achieve full function. It can also lead to a renewed organ failure. This can be caused by a rejection reaction in which the immune system of the organ recipient turns against the foreign organ.
To suppress this rejection reaction, the patient is given immunosuppressive drugs. These are drugs that suppress the immune system, but can also have side effects such as nausea and vomiting, mild susceptibility to infections or dizziness. In the case of organ rejection after organ transplantation, the recipient’s immune system turns against the transplanted organ.
In doing so, the immune cells recognize that the organ is a foreign cell, which is then attacked. The mechanism is similar to that of infection with bacteria or viruses. The body forms so-called antibodies, which, together with inflammatory cells, are directed against the foreign tissue and try to damage and eventually degrade it.
The rejection can vary in intensity and course, which is why different forms of reaction have been defined. Hyperacute rejection is an immediate reaction. The corresponding antibodies are already present, for example in cases of blood group incompatibility, and react immediately with the transplant.
Masses of coagulation reactions occur, which can be life-threatening and require immediate removal of the donor organ. Although acute rejection is also mediated by the immune system, it only occurs in the course of the disease. After several days, but also after months or years, certain defence cells (T-lymphocytes) are directed against the protein structures in the foreign tissue, according to experts.
This reaction can be prevented by the administration of drugs that suppress the immune system – immunosuppressive drugs. Therefore, acute rejection is not necessarily associated with the removal of the donor organ, but if it occurs several times, it leads to cell damage and ultimately to organ failure.In contrast to the acute, rapid reactions, some patients also experience chronic rejection. This happens over years and is caused by damage to the blood vessels supplying the donor organ. Inflammation with subsequent scarring causes the vascular system to constrict, which leads to inadequate blood supply to the tissue. The organ gradually loses its function until it fails completely and must be replaced.
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