Brain repair companies sharpen their drills

LONDON, Nov 10 (Reuters) - A local anaesthetic, a small drill-hole in the skull and a syringe full of new cells may one day be all it takes to repair brain damage.

That, at least, is the hope of scientists pioneering a new kind of "brain repair kit" using implants of mass-produced cells to patch up damaged grey matter.

The daring approach offers hope to those incapacitated by stroke or degenerative diseases such as Alzheimer's or Parkinson's. However, experts say it will take years before it is proven to be safe and effective.

A growing number of companies are lining up to commercialise the technology, including Britain's ReNeuron--a spin-off from the Institute of Psychiatry--which planned to raise $22 million to $29 million with its initial public offering on London's Alternative Investment Market this week.

ReNeuron uses neural stem cells, grown in culture from aborted foetus tissue, to regenerate damaged parts of the brain. Stem cells are "master" cells that can be coaxed into forming many types of tissue in the body.

It has proven the principle in rats and plans to start trials on humans in the second half of next year.

ReNeuron is not alone. At least five other companies are operating in the field, with the most advanced work to date done in the United States.

The idea of transplanting cells into damaged brains is not altogether new.

For the last 10 years, doctors have been treating a handful of Parkinson's disease patients using cells transplanted from the brains of aborted foetuses. The technique, pioneered by scientists at Sweden's Lund University, has been shown to alleviate the worst symptoms of the disease.

But it takes an average of six foetuses to treat an adult brain, making the process practically--and ethically--problematic.

Biotechnology companies believe they have now found ways round this supply problem.

One option, being pursued by ReNeuron and several others, is to use genetic engineering to "immortalise" human cell lines, which can then be produced indefinitely in the laboratory.