Could Sunscreen be a Treatment for MS?

Recently, you may have heard about a study that has revealed that sunscreen (or more accurately certain compounds in sunscreen) can prevent the development of disease in a mouse model of multiple sclerosis.  This research was conducted by a team at the University of Wisconsin-Madison and published in the Proceedings of the National Academy of Sciences of the United States of America (PNAS).

To put this study into context, it was based off earlier work that had suggested UV light radiation could block the formation of disease in the mouse model of multiple sclerosis (experimental autoimmune encephalomyelitis or EAE).  Therefore, as sunscreen is meant to protect against UV radiation, the researchers thought they would test a number of different sunscreens to see whether or not it made the mice get EAE again.

However, what they found was almost exactly the opposite.  What they actually saw was that some of the sunscreens could completely stop the formation of disease in the mice.  By looking at the ingredients for the sunscreens that did manage to stop EAE from developing, and comparing them with those that did not have an effect, the researchers were able to identify two compounds that seemed to be the active components.  These were homosalate and octisalate.

In this study, the mice were given the animal model of multiple sclerosis by injecting them with parts of myelin proteins.  It was found that the sunscreen treatment was only effective if it was started before or at the time of injection.  In mice who began sunscreen treatment when the disease began to appear, no benefits were observed.  The study also provided some evidence to suggest that the more sunscreen that was used, the greater the symptoms of the disease were reduced.

It is important to note that this is a very preliminary study, that will require much more investigation before it is considered useful for people with multiple sclerosis.  Firstly, the study will need to be replicated in a much larger group of mice before small human trials are even considered.  Secondly, whilst mouse models are very helpful starting points for multiple sclerosis research, there is no guarantee that these results would be the same in human trials.  Thirdly, these compounds have previously raised potential health concerns in humans, leading to their use in sunscreens and other cosmetics being regulated.  All three points must be taken into account as this research progresses.

So while the idea that sunscreen (or compounds in it) could be a novel treatment for multiple sclerosis, I don’t think we are at a point yet where everyone should be covering themselves in it on a daily basis!  It is an interesting finding that will require much more work and we look forward to seeing how it develops.