Nature, reserve of human organ? On the ethics of xenotransplants

2000/11/01 Escajedo San Epifanio, Leire - Konstituzio Zuzenbideko IrakasleaEHU Iturria: Elhuyar aldizkaria

• Medikuntza

Thanks to improved immunosuppressants and the advancement of genetic engineering, some scientists have announced that xenotransplants are in a position to investigate in humans.

This has sparked the ethical debate. Xenotransplants meet a number of ethical principles so far and new questions arise. If acceptance of this technique is fundamental to society, the prevailing ethical principles should be subject to a series of changes, as has happened in many other times throughout history. However, if ethical barriers were insurmountable, this technique would be prohibited.

It is not easy to say whether it is better to renew ethics or keep it as it is. We live in an ethically plural and changing society, which always leads us to seek the consensus of the majority with this type of debate. But, in addition to this difficulty, xenotransplants present other difficulties of decision, the strength of their favorable and unfavorable opinions in the most developed sociological research. Our goal is to express the most important ethical principles that attack xenotransplants, as well as the details of the debate.

Conclusions to the recipient

It took more than a decade to solve the problem of interhuman transplants (allotransplantations) with respect to the ethical approaches of that time. The rights of the patient, respect for the deceased, use of immunosuppressants, protection of identity and many other problems were involved. It was decided to reform many of the ethical principles prevailing in society at that time to the new times.

But in this new form that was created for allotransplantation, xenotransplants are not comfortable either. Compared to allotransplantations, the immunological effects that may occur on the receptor are more severe. Organs of another species can cause serious rejection in the body and destroy the vaccinated organ or attract other diseases. In addition, it is not known whether an animal's organ can adequately cover a person's bodily needs for long periods of time.

The point is that the only way to know these aspects more accurately is through clinical trials with humans. As long as appropriate virtual models are not developed (with the help of computers), we should at least isolate socially and rigorously control the people involved in these clinical trials.

Risk of unknown diseases

The elimination of natural borders between species, in the case of xenotransplants, can attract diseases hitherto unknown in humans. To detect the importance of this risk, let us recall two known examples of viruses and infections from animals to humans: AIDS and Ebola virus. According to the studies carried out by the Chair of Law and Human Genome, more than half of our population see here the main reason for their opposition to these techniques. If xenotransplant research continues, any clinical trial of this technique should protect the interests of society and create an organization that considers trial results for the future.

Animal donors

It is clear that for the success of xenotransplants it would be better to use the animals (primates) phylogenetically closest to humans in experimentation and as donors. Better if genetic engineering is applied to prevent rejection or improve organ function. But the ethical sensitivity of our culture in animals, especially primates, hinders these possibilities. Permits to carry out research with primates are very scarce and in the case of other organ donors, it should be noted that without this extracted organ, animals will not be able to live often. Due to their sensitivity and economic argument, pigs have been the most used in the research of xenotransplants. However, as it is not so close to humans phylogenetically, the results of these trials leave many doubts unresolved. Genetic manipulations towards xenotransplantation are also ethically limited. The ethical principles prevailing so far do not admit any manipulation that alters the animal phenotype (aspect of its species). And although phenotype is not altered, the only genetic changes admitted for xenotransplants are those intended to overcome immune barriers. Therefore, although manipulations to improve the functioning and duration of organs (to solve physiological problems) may be possible, they are currently not ethically approved.

What is the situation of the debate?

Due to ethical concerns, in countries where allografts meet a very important percentage of the need for organs, as is the case in Spainia, xenotransplant testing permits in humans are distant. However, in other countries the number of people who do not expect to receive a transplant is too high and governments cannot maintain pressure. It is believed that the United States, Germany or another country will allow xenotransplants to soon try in humans. They already have long lists of people who have offered to rehearse.

In view of the situation in these countries, we believe that closed attitudes against xenotransplants are agitated. It is necessary to investigate whether it is possible to organize appropriate safety measures and controls and whether there are means to avoid adverse immune consequences. If there were the possibility of meeting these two requirements, for our part, there would be no ethical obstacle for xenotransplantations to try clinically in humans. As in the case of allotransplantation, if there are certain guarantees, this technique should be given the opportunity to expose its suitability, without judging previously.

In turn, if we do not meet the two requirements we have put to start clinical trials (or more specifically, while they are not met), we are totally against xenotransplants being attempted with humans. We are convinced that the interests of those who favor starting xenotransplant sessions immediately, without these guarantees, are not very clear. On the occasion of other economic interests and so many scientific uncertainties, we would like to know all the information and expectations they have provided to people who have voluntarily submitted to clinical trials.