ACCESSION NO:  96-97-1058
       TITLE:  The Animal Heart of the Matter
      AUTHOR:  KOECHLIN, FLORIANNE
     JOURNAL:  Ecologist
    CITATION:  May/June, 1996, 26: 93-97.
        YEAR:  1996
    PUB TYPE:  Article
 IDENTIFIERS:  ORGAN TRANSPLANTS; TRANSPLANTATION; XENOTRANSPLANTATION; 
               ANIMAL ORGAN DONORS; GENETIC ENGINEERING; PIGS; BABOONS; 
               CROSSOVER DISEASES
    ABSTRACT:       Human to human organ transplants have become routine. As 
               the demand for operations has increased with soaring success 
               rates, a shortage of spare body parts has developed. Another 
               alternative is a new push to use baboons and genetically-
               engineered pigs as sources of organs for humans. A company 
               called Imutran in the U.K. will conduct human trials using 
               genetically modified pig organs by the end of 1996. 
               Transplanting animal organs to humans is called 
               xenotransplantation. Profits from this procedure could be 
               great. Companies developing the techniques stand to make 
               substantial profits and the number of transplants could grow 
               exponentially. Pig organs could provide revenues of $5 
               billion by the year 2010.
                    Xenotransplantation has been attempted in many forms 
               with varying degrees of success for many years. None has yet 
               been successful long-term, with most patients surviving only 
               a short time in acute discomfort. Most failures are due to 
               hyperacute rejection--the recipient's immune system reacts to 
               cells identified as foreign. The greater the differences 
               between body cells and foreign cells, the more severe the 
               rejection. In some cases, pig organs transplanted into humans 
               were attacked so quickly, the organ disintegrated within 
               seconds. Human cells have a surface coated with proteins that 
               prevents the immune system from attacking them. Researchers 
               hope to use genetic engineering to create transgenic pigs, 
               whose cells will produce these human protective proteins. The 
               transplanted organ will trick the patient's immune system 
               into thinking it belongs.
                    The race is on to develop this technology, but many 
               think things are moving too fast, and that researchers are 
               ignoring significant risks. Animals may harbor viruses, 
               bacteria, and prions that are harmless in the animal, but 
               that could mutate or recombine in the human body to cause 
               diseases that could spread throughout human populations. 
               Disease crossover between species is a well-established 
               phenomenon. Crossover versions of pathogens may cause 
               different and possibly more serious diseases in other 
               species. Crossover may be controlled by raising transplant 
               animals in sterile environments and by screening for 50 
               pathogens before an operation.
                    An ethical question arises with xenotransplantation, 
               too. Is it right to use animals as spare parts? In a 
               transplant patient, animal cells disperse throughout the 
               body, blurring the line between animal and human. 
               Xenotransplantation offers a great hope and a great risk, but 
               the decision to go ahead with research should be made by an 
               informed public.