Answer to avoiding brain damage may be in the air all around us

Scientists have found that a rare component of air could prevent some of the most common forms of brain damage.

The protective powers of xenon were revealed by Mervyn Maze, professor of anaesthetics, and Nicholas Franks, professor of biophysics and anaesthetics, at Imperial College, London.

The use of the inert gas is to be trialled on heart bypass patients, many of whom suffer subtle forms of brain damage. Other research will examine if xenon can also reduce the impact of strokes and even head injuries.

Xenon gas is a known anaesthetic, but its rarity makes it dear - it constitutes just 0.000009 per cent of air.

An investigation into how anaesthetics work led researchers to a hunch that the gas could protect brain cells from damage. This has been borne out by experiments, the results of which are to be published in the journal Anesthesiology .

When brain cells die, they release a flood of neurotransmitters that can in turn cause nearby cells to die. This can have a devastating effect. Xenon seems to interrupt the process by binding to a key brain cell protein, called NMDA receptor, that must be activated by neurotransmitters if the damage is to spread.

The scientists have found that small quantities of the gas can move rapidly to sites of brain damage and appear to have no side-effects. Professor Maze said: "All of the data suggest that xenon is highly efficacious, perhaps the most efficacious, nerve protectant that's available."

About a third of the 28,000 patients who undergo coronary artery bypass surgery in the UK each year are believed to suffer some form of brain damage involving memory loss and sometimes a reduced life expectancy. Phase-three clinical trials to show that xenon gas can prevent this are about to begin.

If successful, the approach may be developed further to buy precious time for many of the 100,000 people a year in England and Wales who suffer strokes. Much of the brain damage they suffer comes in the chain reaction that follows the initial episode.

A spin-off company called Protexeon has been set up to exploit the approach. A joint development programme with US industrial partners Air Products aims to produce appropriate delivery methods.