Cannabis 'cure' for brain injury
Daily Mail Dec 14, 1999
A NEW drug extracted from the cannabis plant could save the lives of accident victims suffering from brain injuries. Each year, hundreds of people are killed or left mentally and physically disabled as a result of such traumas.
Neurosurgeons believe lives could be saved and disability avoided if a treatment was available to stop brain cells literally killing themselves.
The damage in head injuries is almost invariably exacerbated by the release of toxic chemicals caused by the blow to the head. A chain reaction leads to the destruction of irreplaceable brain cells.
For years, scientists have been looking for a way to prevent this process but, until recently, all attempts at finding a drug have failed.
Then scientists turned their attention to the cannabis plant and discovered, through animal experiments, that it had the ability to block brain-cell destruction.
The Israeli scientist who first identified the active ingredient in cannabis was asked to help develop a drug with the same properties of stopping cell damage but without the narcotic effect.
For the past two years, dotors in Israel have carried out successful trials on more than 100 patients. In many cases, the drug, known as dexanabinol, has not only saved lives but has prevented people being confined to wheelchairs or left unable to communicate.
Early in the New Year, neurosurgeons in Britain will be using the drug as part of multinational trials.
One patient whose life was saved by the drug is 18-year-old Asaf Yefet, who works on a farm near Tel Aviv. Two years ago he was thrown to the ground and suffered severe head injuries when a car ran into the horse he was riding.
On arrival at hospital, Asaf's parents were told he had only a 3 pc chance of surviving. He was immediately entered into the trial being run by Dr Maschon Knoller, head of neurosurgery at the Tel Hashomer Hospital in Tel Aviv.
Within hours the teenager was being given dexanabinol via a drip in an attempt to stem the damage to his brain.
'We know that this drug must be given within the first few hours after an accident — time is crucial,' says Dr Knoller. 'If it isn't administered quickly, damage can be irreparable.'
Asaf regained consciousness after five days and went home after three weeks, but it took a further three months before his recovery was complete.
The final clinical trials, next year, will prove if the drug is really effective, but Asaf is convmced dexanabinol saved his life. 'I had a friend who had a similar accident and is now paralysed,' he says.
Miraculously, Asaf suffered only minor brain damage — he has difficulty concentrating — but without the drug the outcome would have been far more serious.
Professor Chaim Aviv, whose Israeli company, Pharmos, has helped turn cannabis into a useful drug, has high hopes for dexanabinol. 'Several pharmaceutical firms have tried to develop a drug for head Injuries, but I think this one is proving the most successful,' he says.
The drug seems to inhibit the production of glutomate, the scavenging enzyme, normally present in small quantities in the brain, responsible for the effects of brain damage.
'When someone suffers a severe head injury, too much glutomate is produced,' says Professor Aviv. 'The glutomate stimulates the production of calcium, which penetrates the walls of brain cells, causing their destruction.
'We call it cell suicide, and once those cells are gone they cannot be replaced. Victims can lose the use of vital areas of the brain controlling speech and movement.
BUT dexanabinol could yet make an even bigger contribution to medicine. 'We think it would be suitable for use in treating brain haemorrhages and strokes,' says Professor Aviv. 'We know that the same destruction is caused when a stroke bleeds into the brain.
'If it was to work for strokes, it would be a major breakthrough in treating the disease, because at present there is little that can be done to prevent this kind of damage.
Bill Alker, of the National Head Injury Association, says dexanabinol could have a major impact in this country, saving lives and preventing permanent disability.
'A third of all victims of severe brain injury die, which is tragic. But what is of great concern is the large numbers who survive,' he says.
'Many are wheelchair-bound and unable to look after themselves. We estimate that 135,000 people in the UK need round-the-clock care because of such injuries. Dexanabinol could make a major impact.'