Transplantation involves transplanting the organic material of another person into a patient. This transplant must take place with consideration of immunologic effects and carries a high risk of rejection, but in current medicine this risk can be reduced by immunosuppressive measures and the co-transplantation of stem cells or white blood cells. Those waiting for a specific organ, organ system, limb, or cells and tissue parts are placed on a waiting list, where general health, age, and the chances of success of the procedure, among many other parameters, determine a patient’s placement on the waiting list.
What is transplantation?
Transplantation involves transplanting the organic material of another person into a patient. For example, in addition to organs and organ systems, tissue components, limbs, or cells can also be transplanted. The term transplantation is used in medicine to describe the transplantation of organic material. This organic material can be various body components. In addition to organs and organ systems, tissue components, limbs or cells can also be transplanted, for example. In contrast to transplantation, implantation does not work with organic but with artificial materials. Prostheses, for example, are implants, while a transplanted heart corresponds to a transplant. In 1983, Theodor Kocher performed the first transplantation on a living human being when he transplanted thyroid tissue under the skin and into the abdominal cavity of his patient. It was not until the 20th century that the umbrella term of transplant medicine, coined by the transplant physician Rudolf Pichlmayr, became established with regard to such operations. Today, transplantations are differentiated depending on the origin, function and location of the transplant. In isotopic transplantation, for example, the tissue and location of the organic material in the donor and recipient remain identical. Orthotopic transplants, on the other hand, match in recipient and donor only with respect to location, while heterotopic transplants have no inherent local match at all. With regard to the function of the graft, a distinction is made between four different subgroups. In allovital transplantation, for example, the graft is vital and fully functional. Transplants of allostatic transplantation, on the other hand, are temporary in their function, while those of auxiliary transplantation are intended to support a diseased organ. Substitutive transplants, on the other hand, replace organs that have become completely non-functional. With regard to the origin of the graft, there are two possibilities: either the material was taken postmortem, that is, after death, or from a living donor.
Function, effect, and goals
The goals of a transplant depend on the individual case. Most commonly, transplants are performed to replace a nonfunctioning or compromised organ or organ system to save the patient’s life. In such a case, the organ that has become useless is completely explanted. This distinguishes this type of transplantation, for example, from operations that implant a second, healthy organ in addition to a patient’s existing and possibly weak organ to support the low performance of the patient’s own organ. Sometimes, however, a healthy organ must be explanted from a patient due to surgery, which can then be transplanted to a recipient. Such a scenario is technically called a domino transplant. Although heart transplantation is certainly one of the best-known types of transplantation for some forms of myocardial disease, there are many other scenarios in which a transplant is indicated. For example, in chronic renal failure, a kidney transplant is often required to save the patient’s life. Patients of Eisenmenger’s reaction, on the other hand, require a combined heart–lung transplant. Liver cirrhosis, in turn, may be an indication for liver transplantation. Cystic fibrosis requires a lung transplant, while leukemia patients are often saved by a stem cell transplant. For conditions such as breast cancer, reconstructive surgery via tissue grafts may be able to restore the female breast.Burns often require skin grafting, while severed limbs, for example, can be transplanted after accidents.
Risks, side effects and dangers
The greatest risk of transplantation is usually an immunologic overreaction that can lead to rejection of the foreign material. The immune system is trained to detect and expel foreign substances from the body, which outlines the basis of graft rejection. In peracute rejection, the graft is rejected in the first few hours after surgery. Allospecific and blood group-specific antibodies are responsible for this, causing fibrin deposits to form in the graft vessels. As a consequence, the implanted tissue dies. While this form of rejection is hardly treatable, acute rejections in the first weeks after surgery can often be contained by immunosuppressants and similar measures. Such acute rejections are cellular interstitial rejections and occur more frequently in kidney transplants, for example. Chronic rejection, on the other hand, usually occurs years later and is related to chronic inflammatory processes due to immunological reactions. This type of rejection necessitates repeated transplantation in most cases. Meanwhile, transplantation medicine has discovered the additional transplantation of white blood cells and exogenous stem cells as a way to reduce the risk of rejection. Not every transplant is suitable for every patient. Immunologically and blood group-wise, for example, the explanted materials must match the patient to be promisingly transplanted. Since there are usually far fewer transplants available than are needed, there are waiting lists in Germany. Whether and how high up a patient is on a waiting list depends on the patient’s general condition, chances of success, age and many other factors. Transplantation is now done across countries so that organs can be found more quickly in acute cases and, in particular, more suitable materials can be arranged.
