Xenotransplantation essay help
Organ transplantation is one of the recent developments in science, and a process that scientists will succeed in saving the lives of thousands of people with malfunctioning every year. The fact that the number of people in need of organs exceeds the number of donors has forced scientists to seek the transfer of animal organs to human bodies. In the past forty years, hundreds of experiments have been conducted in this field known as xenotransplantation, yielding different and controversial results at times. The chimpanzee and the baboon are no longer a first choice for scientists, and today, it seems that pigs may actually be the major donor of organs to human beings. Pig xenotransplants, however, still involve a number of few scientific, religious, and moral concerns.
Organ transplantation from one human being to another has been conducted for many years, and recently, the number of these operations has increased dramatically as more people starting offering their organs for donation either during their life or upon their death. In the US, for example, in 1994, 3,000 people donated organs while they were alive, and 16,000 offered organs upon their death. Yet, this was not sufficient to meet the needs of more than 37,000 who were in need for organ transplants (“Transplantation, p.2).
Transplants are mainly needed by patients whose organs are no longer functioning well, specifically organs such as the heart, the kidney or the liver. Heart failure, alone is a leading cause of death in many countries, yielding four times as many as HIV does every year (Michler, p. 1). Such organs cannot be donated by living human beings, and the prospects of successful transplants from an old-aged person or from a person who died during an accident are not very high, especially that the tissues of the donated organs have to be compatible with the tissues of the recipients, something hard to achieve even among relatives (Michler, p.1). Xenotransplantation from pigs, on the other hand, offers solutions to several problems.
Xenotransplantation was first conducted in the early 1960s when a dozen people had baboon livers transplanted. Eventually, they all died within a period of two years, but at the same time, attracting attention to a new dimension in surgery. Chimpanzees and baboons were considered as primary sources of organs because their biology is quite close to that of humans. However, the fact that chimpanzees are facing extinction forced scientists to search for other alternatives. Similarly, the small size of baboons made them suitable to donate organs to human children. In addition to this, both chimpanzees and baboons were risky sources of organs because their bodies contain many viruses that can jump species and infect human beings (Michler, p.4).
With all the limitations related to the ability of the chimpanzee and the baboon to supply organs for xenotransplantation, scientists started to focus on pigs. To start with, pigs are very abundant, and their organs are very similar in size and function to those of human beings. More importantly, pigs suffer less viral infections than most other mammals. Furthermore, scientists have for years been successfully using the heart valves of pigs to replace those in human beings suffering heart problems (Michler, p. 4).
The possibility of using pigs as a source of organs for human beings has been hampered by a few impediments. To start with, several viruses that were previously unknown to scientists were discovered in pigs, the most recent of which was known as the PERV. Although this virus is harmless to pigs, scientists found that it could infections in human beings. These discoveries have forced scientists to study in more depth the biology of pigs before xenotransplantation could be announced to be safe (Sinha, p.72). Another problem is that human bodies will most likely reject organs transplanted from pigs once these transplanted organs are recognized as foreign by the human defense systems (Sinha, p.70).
For a while, such impediments seemed to be insurmountable, but with advancement in genetic engineering, scientists are now preparing for a new breakthrough. Genetic modification of pigs aims at achieving three objectives. The first objective is to genetically engineer new species of pigs whose organs are more similar to those of human beings. The second objective is to reprogram the biochemistry of pigs such that their organs will contain tissues which will not be recognized as foreign by the human defense systems. The final objective aims at dealing with the long-term rejection by the human body, and hence, to make the transplanted organ invisible to defense systems, scientists aim at modifying more genetic aspects of pigs while at the same time developing new drugs that will prevent rejection by the human body (Sinha, pp. 70-71).
Scientific problems facing xenotransplantation
The scientific problems facing xenotransplantation from pigs are not impossible to deal with. Scientists believe that in the coming few years, they will have developed a much more advanced understanding of the human and pig biology. Once this step is achieved, genetic modification of pigs will be much easier and more well defined (Sinha, p. 72). Still, there are a number of problems that should be considered seriously, particularly moral and religious considerations that relate to xenotransplantation.
Religious authorities in Christian, Muslim, Jewish and other communities have been quite flexible towards xenotransplantation, specifically when the organs were taken from chimpanzees or baboons, and more importantly, when the xenotransplantation was essential to save a human life. With pigs, however, there seem to be some serious doubts. Muslim and Jewish authorities regard the pig as an unclean animal, and although they may be flexible towards xenotransplantation from pigs, Muslim and Jewish communities may impose serious psychological pressures on an individual who undergoes xenotransplantation from a pig (Daar, p. 229).
Another serious question that is getting more attention in the United States and Europe is the availability of animals for testing. For every breakthrough in xenotransplantation, thousands of experiments are conducted on many animals, most of which end lifeless. Animal rights groups have for years been lobbying against such scientific experiments, arguing that with awareness and education, human organs will eventually be abundant to meet the demand on body organs. Accordingly, argue these groups, there is no reason to torture and kill thousands of animals every year if in the future there will be no use out of all these experiments (Daar, p.226). These arguments make sense, because indeed the number of potential and actual donors has been increasing dramatically. Hence, the number of human organs supplied will in a few years meet the demand, perhaps even before pig organs may be ready for safe xenotransplantation. This could simply make all the experiments on pigs and other animals futile. Yet, it is not certain whether human organ supply will be indeed sufficient or whether pig organs will actually become safely available in the foreseen future (Daar, pp. 229).
In the past four decades, xenotransplantation has developed in a dramatic manner, and today, with the help of genetic engineering, pig organs may be available to replace weary human organs. Pigs have proven to be safer donors, more abundantly available, and above all, much easier to be genetically modified. These prospects have encouraged scientists to keep carrying on scientific research on the potentials of xenotransplantation from pigs, even though animal rights groups and ethical or religious considerations may still need to be dealt with. At the same time, education and awareness remain an important means of making human organs available for needy patients.
Daar, A. S. “Analysis of factors for the prediction of the response to
xenotransplantation.” Annals New York Academy of Sciences, 1998: pp.
Michler, L. “Xenotransplantation: risks, clinical potential, and future
prospects.” EID Online, www.cdc.gov/ncidod/EID/vol12no1/michler.htm, January-
March 1996, pp.1-12.
Sinha, Gunjan. “Organ Cowboy.” Popular Science, October 1999, pp. 68-73.
“Transplantation.” Encyclopedia Encarta, CD-ROM: Microsoft Inc., 1998: pp.