Transplantation involves surgically transferring a graft (tissue or organ) from one organism to another so that it can function properly. This method is now widely accepted for treating end-stage multiple organ failure.
Please memorize the following information about the four types of transplantations
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An autogenous transplant refers to a situation where the donor and the recipient are the same person. For instance, when skin is taken from one part of the body and transplanted to another, or during a coronary artery bypass grafting, a blood vessel from the same person is used to bypass a narrowed coronary artery.
An isogenic transplant occurs when an organ is taken from a genetically identical individual, such as from an identical twin.
An allogeneic transplant involves taking an organ from a genetically similar individual of the same species. It is the most commonly performed type of transplant.
A xenogeneic transplant involves using a graft from a different species than the recipient. So far, long-term success in this type of transplantation has not been achieved.
Organs and tissues can be transplanted, not only organs. It is impossible to describe in detail all operations involving organ or tissue transplantation, but you should be aware that transplantation involves:
It is worth knowing that multi-tissue transplants, e.g., upper limb or face transplants, are currently performed.
Kidney transplantation is one method of renal replacement therapy. Successful kidney transplantation is a treatment for kidney failure, but it does not mean a cure, i.e., a return to health. This is the most effective method of renal replacement therapy because the transplanted organ can take over all the functions that healthy kidneys perform in the body.
The transplanted kidney must come from a donor with a compatible blood group and should be best-matched tissue antigen compatibility. There are three sources of kidneys for transplantation:
There must always be a certainty that the transplanted kidney is fully functional. In the case of a living donor, certainty must apply to both of their kidneys to ensure that the kidney left in his body will ensure normal functioning. In people with diabetes, it is possible to undergo simultaneous kidney and pancreas transplantation.
A transplant can be performed in a patient already treated with dialysis or in a patient who has not yet been treated with renal replacement therapy (so-called pre-emptive transplantation). Kidney transplantation, as the most effective method of renal replacement therapy, should be considered in every patient who has no obvious contraindications.
In the absence of the contraindications, a detailed assessment of the health condition is performed – and if no obstacles are still found, the patient, after being qualified by an appropriate team of specialists, is placed on the waiting list for a transplant.
It is impossible to predict how long the patient will wait for a kidney transplant from a deceased donor—it may be short (weeks) or long (years)—because the appearance of an organ that will be compatible with the recipient's tissues is random. Patients waiting for a kidney have their health status periodically assessed to exclude contraindications.
The situation is different when an organ is from a living donor. In this situation, tests should be performed on a pair of people, i.e., the recipient and the donor. After excluding contraindications, kidney retrieval and implantation operations can be planned and performed.
During a standard kidney transplant procedure, the kidney is placed in the lower part of the abdominal cavity over the right or left iliac plate, connecting the kidney artery and vein to the iliac artery and vein, and the ureter is sewn to the urinary bladder. In some cases, the transplanted kidney starts working already during the operation, producing urine. In other people, full kidney function may develop gradually over days or even weeks, and during this period, dialysis treatment is still necessary.
A kidney transplant recipient must constantly take immunosuppressive drugs and receive their first dose before the procedure. These are usually two or three medications that need to be taken at exactly the prescribed doses and regular intervals. Drug doses are selected based on measurements of their concentration in the blood.
As time passes after the transplant, these doses are reduced because the risk of rejection decreases. Suppose no complications occur after the kidney transplant surgery and the transplanted kidney functions properly. In that case, the patient returns home after approximately 2 weeks with a recommendation to report to the transplant clinic at the scheduled date or in case of any disturbing symptoms.
The patient must remain under specialist supervision throughout their life with the transplant.
The quality of life improves significantly in people after a successful kidney transplant. Good function of the transplanted kidney eliminates many chronic complications related to long-term renal failure (e.g., hyperparathyroidism and other hormonal disorders, skin itching, anemia, and bone disorders); there is no need to observe burdensome restrictions on the amount of fluids and types of food consumed, it is possible is a return to active professional work and many recreational sports.
Remember, almost anyone can be a potential organ or tissue donor. There's no specific age limit; often, even if one part is affected by disease, other parts can still be healthy. Organ donors leave it to the experts to decide which parts are suitable for donation and transplantation.
When available, the health of your organs and tissues will be assessed. If you are considering being a living donor, healthcare providers will evaluate your organ's health and overall well-being to ensure your safety before proceeding.
Most transplants are performed using organs and tissues taken from deceased persons unless they have expressed objections. Of course, a person is qualified to donate organs when all other methods of treatment have been exhausted and a committee has confirmed the patient's brain death. The declaration of brain death allows the disconnection of the equipment supporting respiratory functions.
Checking if the organs can be used for transplants involves finding why the organs might not be suitable for transplantation based on the interview, the donor's current health, and test results. Absolute contraindications to organ donation are:
Relative contraindications are:
In addition to contraindications that can be assessed before surgical collection, there are the so-called contraindications revealed intraoperatively, i.e., members of the harvesting team may decide not to donate based on the macroscopic appearance of the organs.
The most common transplant type is allogeneic transplants, in which the donor and recipient are matched for immunological compatibility. However, despite efforts to match donors and recipients, this type of transplant involves transferring foreign tissue into the recipient's body.
The immune system recognizes foreign antigens in the transplant and tries to defend the body against foreign tissue, triggering a cascade of biochemical reactions aimed at destroying the transplanted organ. For this reason, immunosuppressive treatment is necessary to suppress the recipient's immune system and prevent transplant rejection.
This treatment aims to achieve long-term tolerance to the transplanted organ. Progress in transplantology was possible, among other things, thanks to the discovery and development of a therapy that inhibits the activity of the recipient's immune system. Thus, the tolerance of a foreign organ is increased, and the number of transplant rejections is reduced.
Patients need to take immunosuppressive drugs for the rest of their lives, which can lead to side effects.
Different types of immunosuppression are employed depending on the period following transplantation. High doses of immunosuppressive drugs are used during the perioperative and postoperative periods in what is known as induction treatment.
Afterward, maintenance treatment involving low drug doses is continued for life. However, certain drugs may cause immediate side effects such as kidney damage or bone marrow suppression, while immunosuppression also increases the risk of cancer and infections.
The most common complications following organ transplantation are infections, which can result in graft loss and, in severe cases, even the death of the recipient. Infections typically occur between 2 and 6 months after the transplantation procedure. In the initial two months post-surgery, bacterial infections are predominant.
Subsequently, between 2 and 6 months, viral infections, such as CMV, HHV6, and EBV, and fungal infections associated with immune system response inhibition become more prevalent. After six months, the types of infections are comparable to those in the general population.
Viral infections are the most frequent among transplant recipients, mainly due to the immunosuppressive treatment administered to prevent rejection of the transplant. While these drugs effectively prevent rejection, they weaken the immune system, making it more susceptible to viral infections.
The immunosuppressive therapy can reactivate latent infections and increase viral multiplication. Additionally, they can be transmitted from the donor along with the transplanted organ.
Each potential donor is subjected to virological diagnostics for infection with the following viruses:
Organs are not collected from a donor infected with HIV, HBV, or HCV (in the case of the latter, collection is permitted in special situations). The presence of EBV and CMV viruses does not disqualify the donor, although after such a transplant, the recipient is subject to special supervision.
Viral infections affect the recipient's body directly and indirectly. Direct effects include pneumonia or meningitis. The course of such an infection is often mild and quickly becomes chronic. In addition to their direct pathogenic effects, viruses contribute to the chronic rejection process of a transplanted organ and the development of cancer.
Graft rejection is a process in which the body defends itself against a genetically foreign organ or tissue introduced into it, similar to what happens during a bacterial or viral infection. Before transplantation, the harvested organ undergoes tissue typing, a procedure that determines its immunological characteristics.
Then, a recipient with similar immunological properties is sought – such as a matched donor, and the recipient has the lowest risk of transplant rejection. Depending on the time in which graft rejection occurs, we talk about hyperacute rejection (within a few minutes after transplantation), acute accelerated rejection (within 24 hours), acute rejection (days to months), and chronic rejection (one year after surgery).
In addition to immunological factors, transplant rejection is also influenced by the age of the donor, the storage time of the organ, its size, as well as CMV infection, hypertension, and lipid metabolism disorders.
Apart from infections and graft rejections, other complications include:
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