BEIJING, Sept. 12 -- Transplants of animal organs into people could soon be a reality since the biggest obstacle in the way of safe transplants is close to being swept away by new advances.

    As a result, xenotransplantation - placing animal organs into humans - is back on the agenda, said expert Dr Anthony Warrens, from Imperial College, London.

    Pigs are a likely source of transplant organs because they are about the same size as humans and have a similar physiology. Scientists are working to produce genetically engineered pigs whose tissues would not provoke an immune response in humans.

    "One of the attractions of the pig is the widespread acceptance that it is regarded as ethically proper to rear and then kill large numbers of pigs for food," said Dr Anthony Warrens. 

    "Many feel that there is a much lesser degree of ethical challenge to rear these animals to save human life. While there are religious and vegetarian groups who take a different view about the use of animals, theirs remains a minority opinion," he added. 

    With the increasing shortage of donors for organ transplants, the use of animal organs may be the only hope for many suffering from problems such as kidney, heart or lung failure.

    There are about five times more patients than organs available for transplant.

    However, despite the progress made in this field, there are still problems associated with transplanting animal organs into humans.

    Normally planting a pig organ such as a kidney in a human triggers an immediate and deadly immune response.

    The dangers of animal viruses crossing over and infecting humans are still a cause for concern.

    In addition, unknown animal pathogens could prove a potential problem.

    But Dr Warrens added there was good reason to believe it would not be a major problem. Many scientists have called for a moratorium on xenotransplantation until such dangers have been overcome.

    Once scientists have got to the point of starting clinical trials, which could be about five years away, patients receiving the organs will have to be monitored daily for life, according to Warrens. Enditem

    (Agencies)