New target for MS treatment found using old drug

11 November 2007

A drug currently used to treat high blood pressure and heart failure has been found to reduce the symptoms of multiple sclerosis in mice. The discovery that amiloride can reduce the degeneration of nerve tissue in mice suggests it could have a therapeutic potential for people who have MS. However, despite the positive findings, the researchers warn that clinical trials in people, to test the drug’s full potential, are crucial before it is given as a treatment to people who have MS. 

The research led by Professor Lars Fugger of the Medical Research Council Immunology Unit and Department of Clinical Neurology at Oxford University is published in Nature Medicine. Professor Fugger said: ‘‘The interesting thing is that this drug [amiloride] is already licensed for another purpose. Looking for new ways to use established drugs is usually cheaper than starting the discovery process from scratch, we’ve had a really positive result.’’

The search for therapeutic potential began with studies of the role of a channel called, ASIC, that creates an opening in the cell membrane,. ASIC works by sensing acid levels around the cell and lets sodium and calcium molecules into cells. This process is an important part of the process of sensing pain and touch. Using mice with a condition that mimics the human form of multiple sclerosis the scientists found that the ASIC channel also contributes to degeneration of the axon, the long stem of the nerve. When the channel remains open, sodium and calcium can flood into the cell in higher than normal proportions.

Professor Fugger explained:‘‘When sodium and calcium levels accumulate in excessive proportions within nerve cells, the axon, the bit that carries messages from one nerve to the next, is damaged. We found that this damage was reduced in mice given amiloride. The drug appears to work by blocking the action of the channel that lets sodium and calcium molecules into the cell.’’

The research has shown that not only is the ASIC channel a suitable target for drugs that aim to protect against neurodegeneration in research but that amiloride might be beneficial in treatment.

Overall this suggests that drugs targeted at the ASIC channel, like amiloride, could help reduce the level of nerve damage caused by multiple sclerosis. The research team are now beginning to plan a clinical trial that will aim to find out if amiloride is beneficial in treating the symptoms of multiple sclerosis in people.

For further information please contact the Medical Research Council press office on 020 7637 6011 or press.office@headoffice.mrc.ac.uk, out of hours call 07818 428 297.