HEALTH: Animal-Human Transplants Coming

By Gustavo Capdevila Reprint | | Print |

Gustavo Capdevila

GENEVA, Nov 4 1997 (IPS) - International medical experts believe it will soon be possible for doctors to safely transfer cells, tissue and organs from animals to humans.

Specialists from Africa, the Americas, Asia and Europe at a conference here, organised by the World health Organisation (WHO), heard how aninimal-to-human translants could improve the health of the world’s population.

According to Francois Meslin of WHO’s Division of Emerging Diseases and Other Contagious Illnesses, the grafting of cells, tissues, organs or any other matter between species -known as a ‘xenotransplants’ – is currently in advanced stages of research.

Meslin stated that researchers have established a scientific base and levels of experimentation and discussion which will allow for the development of this technology in the near future, but he could not give a definite time line.

Xenotransplant research has gone on for more than 100 years but only in recent times have medical advances enabled transplants of this kind to take place without the danger of infecting humans with animal diseases.

Dr. Rachel Bartlett, of the Nuffield Bioethics Council in England, indicated that transplant research is conducted in the context of ethical prevention.

She pointed out that a primary concern arises from the cases of patients who cannot gain access to the human organs they need to survive. We physicians “have a clear ethical responsibility to deal with their problem.”

Jeffrey Platt from Duke University revealed that in the United States, the supply of human organs can only meet the needs of between 5-15 percent of those who need transplants.

There are some 2,000 heart transplants performed in the United States every year and there there are a further 40,000 patients on waiting lists to receive healthy hearts, stated Platt.

Another question with ethical implications is how to make this technology accessible to all of those who need it. Bartlett admitted that these procedures “will be very costly,” and that they will only be available in industrialized nations. Still another concern is the genetic engineering of pigs, which are most likely to be the principal donors of xenoplastic material for humans.

Bartlett pointed out that pigs are particularly suited for this purpose because their organs are similar in size and because they develop relatively quickly and do not require much care. In any case, the scientists participating in the WHO meeting did not express objections to the use of cloned or genetically modified animals.

“The health of human beings,” they stated, “should be protected and human dignity should be respected.”

The genetic manipulation of pigs would permit the elimination of the factors which cause rejection among patients receiving transplants as well as diminish the risks for the transmission of animal infections to the human population.

Pierre Effa, president of the Bioethics Society of Cameroon, insisted that human dignity must be respected in every stage of the transplant process. He highlighted the shortage of organs for transplant and observed that “the supply is so low that the people of Africa are presently being exposed to the illegal traffic of organs.”

Xenotransplant technology could be a solution “as long as it does not affect the philosophical and cultural foundations of the African world,” Effa said.

Meslin recalled that the experimental transplants carried out in the 1960s failed. Most receiving patients lived for only a few hours after the operation; a small percentage lived for a couple of weeks, at most.

Platt said that during this period, the first transplants of human hearts were almost equally unsuccessful. Following a period of pessimism, heart transplants ended up becoming the preferred treatment for serious and chronic coronary insufficiencies in the United States, he added.

Platt recognized the failures of past xenotransplant experiments, but argued that today researchers have the scientific knowledge to understand the causes of those failures. He said that the pigs that will be utilized will be raised in special environments and will possess enough human genetic material to guarantee tissue compatibility.

Platt admitted that, as in other areas of scientific research, there is a profit motive behind the development of xenotransplants but, “it is not private clinics that are driving this forward. It is the desire of the doctors.”

The researcher also pointed to the frustration faced by physicians who want to assist their patients, but are still unable to offer them this “potentially available” treatment option.

Nevertheless, there are some areas in which experiments involving humans and animals are being conducted, like among diabetics who receive pig cells and in the treatment of serious hepatic infections wherein human blood is cleansed in pig livers or in containers which house pig cells.

Platt also indicated that Parkinson’s disease is being treated by grafting of pig cells onto human patients. (FIN/IS/PC/dg/he/mg/97)