Stem cells aren't miracle cure - Winston

Last updated at 12:32 05 September 2005


Hopes of transforming medicine with stem cell treatments in the next decade have been "hyped up", leading fertility expert and TV presenter Lord Winston has claimed.

Lord Winston said research on embryonic stem cells was worthwhile and likely to yield important new information about cell biology and cancer.

But it was premature to talk of exciting new cures for diseases such as Parkinson's and diabetes.

Lord Winston criticised the scientific establishment for exaggerating the potential of stem cells, and highlighted major obstacles that still had to be overcome.

Speaking on the eve of this year's British Association Festival of Science, starting in Dublin today (Monday), he said: "Science is not about certainty but uncertainty.

"It isn't sufficient for us to make broad statements any more about certainties.

"I think we need to be considerably more modest about our science. We do tend to hype up so many activities. The latest one in biology is the issue of embryonic stem cells.

"I view the current wave of optimism about embryonic stem cells with growing suspicion."

Growing cells

Stem cells are immature cells that can be programmed to perform different functions. Those harvested from early-stage human embryos have the potential to become any kind of tissue in the body, from bones to brains.

Scientists are looking into ways of growing the cells and directing their development.

Experts have predicted that in future this will lead to replacement tissue treatments for curing degenerative diseases or repairing injuries. Stem cells could be used, for instance, to replace lost brain neurons in a person with Parkinson's or Alzheimer's, or renew pancreatic insulin-secreting cells in a patient with type 1 diabetes.

By taking stem cells from embryos cloned from patients, the treatments could be individually tailored to avoid rejection by the immune system.

Some have even speculated on the possibility of growing whole organs, such as kidneys, in the laboratory.

The first treatments could be 10 years away, or even sooner, it has been claimed.

But Lord Winston, current President of the British Association for the Advancement of Science, and Professor of Fertility Studies at Imperial College London, is not convinced.

One of the biggest problems, he said, was that cultured stem cells are inherently unstable. When grown in the laboratory, they often produced cells with chromosomal abnormalities.

They also replicated slowly - so slowly that by the time they would be ready for use as a tailor-made treatment the recipient patient could be overcome by disease.

Ensuring that all the cells being used for treatment did the job they were supposed to do was another problem.

In culture, cells did not develop in exactly the same way they did in the body where they were subject to a complex interplay of genetic influences.

The long term outcome of planting stem cells in a human being was unknown.

"If there was ever a case for more animal research that is one very, very good example," said Lord Winston.

Over-playing the potential benefits of stem cell treatments could rebound on the scientific community, he warned.

"If we run too hard in the political arena, if we try to persuade excellent groups like the Parkinson's Disease Society that very soon we'll have cures for Parkinson's disease, there's going to be a mighty backlash," he said.

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