The Core Challenges of Organ and Tissue Transplantation

The Major Challenges in Organ Transplantation

A transplant is the replacement of a diseased organ, which endangers a person's life, with a healthy one that functions properly. It's not always necessary to replace the entire organ; sometimes, a part of the organ, or even just some tissue or cells, is sufficient.

The therapeutic method of transplanting organs and tissues faces three major problems:

1. Immunological rejection
2. The shortage of available organs
3. The technical impossibility of obtaining certain organs or tissues

Immunological Rejection

Our immune system has the ability to distinguish between 'self' and 'non-self.' When white blood cells detect something foreign, they attempt to destroy it. This response is crucial when the foreign entity is a bacterium or virus, as it helps protect us. However, this becomes a problem when the foreign material consists of donor cells from a transplanted tissue or organ entering the recipient's body.

Therefore, it is essential that the donor and recipient are as compatible as possible to prevent rejection. The recipient's body tries to defend itself by destroying the foreign organ. To avoid or minimize rejection, powerful drugs called immunosuppressants are used. These drugs reduce the responsiveness of the immune system. The problem with this approach is that it also leaves the body exposed to various infections. These drugs must be taken for the rest of the patient's life.

The Shortage of Available Organs

Portugal has one of the highest rates of organ donors. Even so, there are still around 5,000 people on the waiting list. While waiting times for urgent cases are shorter than in other countries, 10% to 15% of patients still die before receiving a heart or liver transplant.

The Technical Impossibility of Obtaining Certain Tissues

Some organs, such as the brain, are impossible to obtain and transplant. It is not yet possible to obtain the nerve cells that could cure conditions like spinal cord injuries. Other neurodegenerative diseases, such as Parkinson's or Alzheimer's, could also benefit from these cells.

Despite the success of transplants, these problems are difficult to resolve. Immunosuppressive drugs have adverse side effects, the number of donations has increased but not enough to cover the minimum needs, and transplanting certain tissues remains challenging.

Because of this, scientists are focusing their efforts on developing new therapies that could eliminate the shortage of organs and tissues for transplants and prevent rejection. These new therapies are part of regenerative medicine, which uses stem cells with the goal of regenerating tissues or organs that are not functioning properly, without causing harm to the patient.