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Scientists Creating Monkeys With Human Brains

Posted on: Monday, 11 July 2005, 18:00 CDT

EXPERIMENTS where human brain cells are injected into monkey foetuses could lead to a moral nightmare, scientists will be warned this week.

A high-powered American committee is to call for restrictions on the research, amid fears that it could produce monkeys with brains that are more human than animal.

A team of neuroscientists on the Caribbean island of St Kitts have already created primates with partially human brains, giving a group of green vervet monkeys up to eight million human brain cells each.

The experiments at the St Kitts Biomedical Foundation have shown that human brain cells injected into the monkey's brains will grow and integrate with their monkey neighbours. The modified animals are termed 'chimeras' after Greek literature's mythical monsters, a combination of lion, goat and snake.

Led by Dr Eugene Redmond of Yale University and Dr Evan Snyder, a professor and director of stem-cell research at the Burnham Institute in California, the team aims to find treatments for Parkinson's disease. Dr Redmond emphasised that the monkeys still had only a very small proportion of human cells in their brains.

He said: 'The most we've put in is about eight million cells and, while that sounds like a large number, the brain has 20 to 40billion. It's hard to imagine that they could do anything to change the characteristics of that brain.' His colleague Dr Snyder has been injecting human brain cells into both unborn and adult monkeys to study neurological illnesses since 2001 and he insists chimeric brains are vital for medical research.

He said: 'If the goal is to derive cells that can ultimately go into a human, one needs to go first into an animal model of a disease that comes as close as possible to emulating a human.' The professor has no concerns that an animal could become humanlike. He said: 'I guarantee that if you had a massively chimeric monkey brain with human cells in it, that monkey would not start writing Shakespeare.' But the fact that 98.5 per cent of our DNA is shared with chimpanzees, and that non-human primates have been taught to behave like humans using words, counting and pointing reinforces concerns that the monkeys might be too close a relative of man for comfort.

The US committee of neuroscientists, bio-ethicists, animal behaviouralists, lawyers and philosophers was set up four years ago to investigate the growing science of human-primate chimeras.

Now the group, based at the Johns Hopkins University in Maryland, is publishing its conclusions in leading journal Science.

The unsettling questions the committee will address include whether introducing human cells into nonhuman primate brains could cause 'significant physical or biochemical changes that make the brain more humanlike' and how those changes could be detected. Also, how could changes in animal 'cognition, emotion or behaviour' be assessed?

The group has also considered moral questions surrounding a humanised monkey, asking: 'Would it be morally problematic to create a chimeric animal with significant human consciousness?', 'Should the animals be treated differently to normal research animals, or given special legal protection?'

And, critically: 'Should this line of experimentation be regulated or prohibited?' Last night co-chair Dr Ruth Faden, a professor in biomedical ethics, said: 'What we were trying to do was anticipate recognising that if science were to take that path there might be some different kinds of moral challenges.' Mythology is full of human-animal chimeras generally sinister or terrifying creatures such as sphinxes and minotaurs. But the idea that primates man's closest relatives could be given human brains is particularly disturbing.

The issue of chimeras has recently come under the spotlight because of the new technology resulting from research into human stem cells in the late Nineties.

Stem cells isolated from early embryos are able to transform themselves into any type of cell in the body, giving them enormous medical potential. In theory, they could be injected anywhere in a patient to provide new, healthy tissue where it is needed.

But before they are used in humans, scientists need to understand how they grow and become specialised, and one option is to use animal models.

In the UK, there are no laws restricting the creation of human/ monkey brains, although chimeras were discussed by a parliamentary committee in March. It did not rule out any kind of human-animal chimeras or suggest limits on the developmental stage of the animal.

Instead it recommended that chimeras be destroyed within 14 days in line with the rules governing human embryo research.

A spokesman for the Human Fertilisation and Embryology Authority said the issue may be considered again when fertility laws are reviewed later this year.

Source: Mail on Sunday; London (UK)

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