Organ transplant from animals may increase life span of humans but could risk quality of health

A hundred years from now, if scientists have their way, many humans will be partly pig and baboon. I mean really, not metaphorically.

Scientists are working on transplanting entire hearts, liver, kidneys, pancreas and lungs from animals to humans. The increasing demand for organs, tissues, and cells, and the dearth of available human organs, have focused scientific interest in taking organs from animals. The term for the transplanting of organs from one species to another is called xenotransplantation and so far it has not worked at all. However, entire corporations are at work, slicing and dicing animals so that one day, humans can be part pig and part baboon.

Representational image. Getty Images.

Representational image. Getty Images.

The arguments, in favour of the animal to human organ transplantation, is that these organs would be available whenever required, instead of making patients wait for months. An immediate transplantation would perhaps result in improved survival. Instead of waiting for a dead human, whose organs are already slightly damaged, the organs could be taken from healthy animals under anaesthesia.

The pig has become the animal of choice for most companies. Thousands of pigs are being killed to use in human bodies. But, before they get to humans, scientists first transplant their organs into the bodies of baboons to see if they can go into a different species.

Why baboons? Humans and baboons have 90 percent of their DNA in common, so the captive animal becomes a stand-in for a human. Why pigs? Their organs are of the same size as humans.

Which is the ideal animal species for organ transplants? The animal should have the same sort of anatomy so that the organ can function well in humans. He should not have any disease that can be transmitted to humans. He should be immune to human diseases. He should have no genes that affect human immune systems. He should be inexpensive to breed and keep and have lots of babies every year. And he should be an animal that humans don’t mind killing. There is no such animal.

Primates may be somewhat alike in anatomy, but they give and get human infections easily. They don’t breed quick enough and humans ( except scientists) don’t like killing them.

The pig has large litters several times a year and is cheap to feed. The problem is that its blood and all its genetics are far too different. The pig is an entirely different species . It has been 80 million years since the pig and human diverged on the evolutionary scale. Is it possible to “outwit evolution.” Not so far. Millions of killed animals later, scientists have not made much progress. The very basic aim—to replace a baboon’s heart with a pig heart—has still not been achieved.

Organ transplants fail because each mammalian species has a system and blood unique to itself and its immune system is built to reject foreign organs. As soon as human blood is sent through pig organs, the antibodies in the human blood cells are activated against pig cells. Companies are working to add human thrombomodulin protein to pig cells to make them seem more human, so that human cells are less likely to reject them. Through microinjection techniques, and in vitro fertilisation, five human genes have been added to the pigs' livers, kidneys and hearts.

The pig has a galactose oligosaccharide enzyme (Gal) which humans don’t. When a pig organ or cells are transplanted into a human, this enzyme causes immediate rejection. Scientists have genetically created a pig that "almost" doesn’t have Gal. However, clinical testing has not finished. The genetically manipulated pigs are called GalSafe pigs.

Unfortunately for the scientists, pigs also have retroviruses in the genome of every porcine cell. These will inevitably be transferred to the donor tissues. This is a grave potential risk, as retroviruses don’t create illnesses in their natural hosts but are devastating to humans. The scientists have discovered a retrovirus in the pig called Perv. Research—published in the journal Science—shows that Perv can make their way from pigs into humans. Opponents of xenotransplantation fear that these viruses, when introduced into a human system, might cause epidemics of diseases for which we have no immunity and no cure.

Large commercial companies like eGenesis claim that they have removed these threatening viruses from the animals' DNA. They have cut out genes and blasted the rest to eradicate all Perv activity to make Perv free piglets.

Scientists say major obstacles remain. “Even if organs from these gene-edited pigs could be safely used to overcome virus transmission, there remain formidable obstacles in overcoming immunological rejection and the physiological incompatibility of pig organs in humans.”

Experts in these fields worry that transgenic pig organs, whose organs are no longer completely porcine genetically, may be even more susceptible to viral infections. The humans that get these genetically modified organs would have to be on immunosuppressants for the rest of their lives. While xenotransplantation may theoretically increase the survival time, it is unclear whether the negative impact on the human’ quality of life would be worth it.

The risk of getting and transmitting disease to the recipient and to society cannot be accurately estimated. What impact will it have on the human race, should a new zoonotic infection be introduced, for which we have no cure? Ebola and Aids have killed millions.

If, in the distant future, a pig organ is ever ready for use on a human, these questions arise:

Should the members of a community, therefore, be consulted if there were any xeno-transplantation donees in their region? Someone will go to court demanding that, in the greater interest of society a person with an animal organ in their body should be restricted from having physical relationships and socialising, to prevent the possible risk to the wider public from zoonosis. This may result in temporary detentions at home, something written in the contract before consenting to xenotransplantation.

How would a patient give an informed consent to the future restrictions of one’s liberty. Would he not challenge the legality of any such agreements later. They could reasonably argue that they have agreed to the restrictions under duress because of a lack of viable alternatives to xenotransplants. Even if they were available, the treatment would be immensely expensive. Production of a pathogen-free donor organ would involve rearing animals in strictly controlled environments.

This means huge costs in developing a sustainable workforce to provide transplantation and post-transplant surveillance of the patient. Insurance providers may not cover expenses of a xenotransplant. Public healthcare providers may decline to provide this treatment, as it may not be cost-effective. Only the very rich will be able to afford it with serious implications for fairness. If public health authorities were to fund expensive interventions like xenotransplantation, other routine treatments of greater medical benefits to society may be jeopardised.

Religions like Islam and Judaism feel that pigs are ‘ritually unclean’. They may therefore not approve of people who have pig organs. Would these recipients be socially acceptable?

The ethical view is that animals have rights similar to those considered appropriate for humans. Is the prolonged suffering, in the form of constant physical manipulation, isolation and death of an animal, moral? Sheep that have been genetically modified to grow more wool are born blind with legs so weak that they cannot move. What are the similar physical consequences in a genetically modified pig.

Wouldn’t it be easier to find a way to grow human organs, rather than killing animals, or modifying them, to become more human? Three-D technologies have come in. Meat cells have been successfully multiplied to make non-animal meat hamburgers. Grow the person’s own organs and tissues and then use them for autotransplantation.

In this amazing world of ours, a human will eat and drink the wrong things, not exercise, abuse his body and spray pesticides everywhere. When his organs start failing he will look for women, poor people and now animals, to give him organs so that he can live to carouse some more.

I am totally against this massive slaughter that is going on in the name of scientists getting jobs and pretending to work for the benefit of humankind. Why not go into a brave new world without any moral barriers and raise humans for the purpose of harvesting their organs.

To join the animal welfare movement contact gandhim@nic.in, www.peopleforanimalsindia.org


Updated Date: Jan 17, 2018 16:27 PM

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