About organ transplants
Let's approach this from a slightly different perspective. There is something else we'd like you to consider when thinking about regenerative medicine.
Various factors can cause organs or tissue to be lost or to undergo a deterioration in condition, and when this happens, it becomes necessary to repair the organ or tissue. A number of different methods of doing this have been thought up thus far. Of course, organ or tissue damage is sometimes cured with medicine. If the damage is slight, you may be able to get by with this. However, if there is a major problem, it cannot be cured with medicine alone.
Organ transplantation has come to be used as a method of treating large-scale organ or tissue damage. Organs or tissue are harvested from deceased donors and used to treat the patient with the disease. Bone and skin grafts have been in use for quite a long time. Kidneys, hearts, lungs, and other organs can also be transplanted. As you all know, "eye banks" exist for corneal transplants, and quite a lot of patients undergo this treatment.
Organ and tissue transplantation of this kind is a very effective treatment method, but if you look at the associated problems, they fall into two major categories. Firstly, since the transplanted organ or tissue comes from another person, there may be a rejection reaction after the operation. The second problem is that it is necessary to search for an organ or tissue donor.
The first type of problem, the rejection reaction, is referred to as an immunological rejection, and this kind of reaction is inevitably triggered if a transplant from another person is put into the body. The body is equipped with a function called immunity, which is designed to eliminate anything foreign to the body itself that comes in from the outside. This works to eliminate things like bacteria that enter the body, but because it is a highly efficient mechanism, it can tell the difference between the patient's own liver or heart and a transplanted liver or heart received from someone else, and it will attempt to eliminate the foreign body. For this reason, it becomes necessary to continuously use drugs that inhibit immune functions. These make it possible to reap the benefits of the transplanted donor organ while inhibiting the reaction that eliminates foreign bodies.
The second type of problem involved in transplantation is what to do about the donor. Apart from cases where the transplant is received from a family member, it is often necessary to receive tissue or an organ donated out of the kindness of a donor who has died. In this case, a transplant from someone who has been ill for a long time is not very suitable because the patient's organs will have been weakened by the illness. So it becomes necessary to consider obtaining a donated organ from someone who died suddenly in an accident and had been healthy until just before. I think you can imagine how difficult it is to obtain tissue and organs from this type of donor.
Many Japanese people are Buddhists. Of course, there are different schools of thought in any religion, but the Japanese tend to regard the body of the deceased as "Buddha" incarnate. It then stands to reason that they will not readily allow an organ for use in transplantation to be harvested from the body of a family member who has met with a fatal accident. A great many people are waiting for an organ donor, but there are no signs of the donor shortage being solved, especially given the special feelings that the Japanese have toward the bodies of deceased loved ones.
Every year, more and more people go to the United States or other countries of Asia to receive organ transplants because of the dearth of donors in Japan. They are relying on the good will of donors in other countries. If we look at it this way, it may be time to reconsider organ transplantation as seen from the value system of the Japanese.