Parkinson drug for multiple sclerosis?
A drug currently used to treat Parkinson’s disease can repair the nerve damage caused by multiple sclerosis, research using rats and mice has shown. The finding offers a possible new approach to treating the neurological disease, which affects around 100,000 people in the UK. If successful it will be the first drug to repair the damaged nerves which are the underlying cause of the disease. 20 years ago there were no effective treatments for multiple sclerosis (MS), a disease that degrades the protective covering of nerves, called the myelin sheath, resulting in vision loss, dizziness, tremors and bladder problems. There are now a number of drugs that treat these symptoms but still no cure.
Now a new study, published this month by scientists at the Scripps Research Institute in California, reveals that benztropine promotes the development of oligodendrocytes (the myelin-forming cells in the brain) in test-tubes and appears to cause the re-growth of myelin in animals with MS-like symptoms.
Their discovery began with an experiment that screened 100,000 substances for their effect on immature oligodendrocytes taken from the optic nerves of newborn rats. More than a dozen candidates gave the researchers what they were looking for: the production by the cells of Myelin Basic Protein (MBP), which is essential for the growth of myelin sheath. In further tests to determine whether any of these substances could induce the growth of the tightly-wrapped myelin sheath essential for normal nerve function, oligodendrocytes treated with the candidate drugs were cultured with nerves taken from rats. In the presence of one of the compounds, benztropine, more myelin wraps appeared around the nerves than in untreated cultures.
How a drug behaves in a test-tube and how it behaves in a living body can be very different. So the researchers tested benztropine in two different animal models of MS. The first mouse had been treated with an antibody that targets its own immune system to attack and destroy myelin, very similar to how it does in humans. Benztropine treatment successfully reversed the disease in these mice and autopsies showed that myelin had re-grown around the nerves. In the second animal model myelin was degraded using a chemical eaten by the mice. In these mice myelin re-growth was also observed.
These are promising early results but the team will need to prove the effects can be replicated in human cell cultures and then human volunteers before patients may benefit. The proven safety of benztropine in patient with Parkinson’s gives this candidate treatment a better chance than most of making it to the MS clinic, although there are known side-effects that may need to be overcome.