Animal organs 'will soon be used for transplants'

The Telegraph
Sep. 10, 2005

The transplantation of organs from animals to humans could soon be a reality, scientists said yesterday.

Speaking at the BA Festival of Science in Dublin, Dr Anthony Warrens, of Imperial College, London, said xenotransplantation, the process of transplanting organs from one species into another, could soon ease the shortages in body parts.

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

Dr Warrens said he would have been pessimistic about the possibilities of xenotransplants if asked five years ago.

However, he said: "There have been significant developments over the course of the past year."

Experiments using GM pigs have led to the survival of transplants of pig tissue in experimental animal models for more than 80 days.

"This is a great advance on the previous life expectancy which could be measured in hours," he said.

"Although the idea of xenotransplantation is far from new, it is only in recent years that many of the potential immunological problems, such as transplant rejection, have been solved, meaning the process of transplanting organs from one species into another, could soon be a reality.

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.

"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.

"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."

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

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.

While scientists can create treatment and transplant rejection prevention strategies for known human pathogens, they are unable to do so for animal pathogens.

Dr Warrens said: "Despite the risks, xenotransplantation may be the best hope we have for dealing with the current transplant shortage. Currently there are around 6,000 on the kidney transplant waiting list, whose condition will only get worse without a transplant.

"Although we can't say there is absolutely no danger of cross infection, I believe that in the future we will be able to deal with many of the problems."

Prof Maggie Dallman, of Imperial College, said rejection of transplant organs and diseases caused when the immune system turns on the body - such as diabetes and multiple sclerosis - could one day be treated with specialised white blood cells to regulate immunity.

The cells are called regulatory T cells, and are involved in controlling the body's response to its own proteins, preventing attack.

Now scientists are working out how to boost their numbers with molecular signals.

"Such regulatory cells have the capacity to prevent rejection of transplanted tissue while leaving the rest of the immune system of the person intact and capable of dealing with an infectious agent," she told the festival.

"Although we have developed effective drug therapies to prevent organ graft destruction in the short term we know that long-term survival rates have not improved with such approaches."