National Eye Health Week – Could our immune system be causing AMD?

Posted: Friday 28 September 2018

Imagine not being able to read the newspaper, or enjoy the autumn flowers in the garden? Imagine seeing fuzzy images and blurred lines? This is what people living with macular degeneration, or AMD, deal with every day. In the UK, around 600,000 people are living with AMD and around 70,000 new cases are diagnosed every year: that's nearly 200 every day!

We know that age and our family history influence the risk of developing AMD, but a number of other things could play a role. Smoking increases a person's chances of developing AMD by 2-5 fold and certain life style choices, such as our diet or the amount of ‘stress’ we experience, can ‘speed’ up the symptoms. These may appear unrelated but if we look at the biology, an emerging trend is revealed: they are linked to inflammation.

Inflammation helps us fight infections by recognising and removing bacteria and viruses. Take for example the complement proteins, which can ‘stick’ to the surface of bacteria to mark them for removal. Another mechanism is the release of highly reactive oxygen radicals, which kill bacteria by pierce holes in their surface. Control mechanisms are in place to protect our own cells and tissues, but when these fail, chronic inflammation and oxidative stress occurs: a major cause of age-related disease.

What has this got to do with AMD?

People with AMD have yellow deposits, or ‘drusen’, at the back of their eye. These drusen contain waste products of the rods and cones which are covered in complement proteins. This attracts and activated immune cells leading to low grade but chronic inflammation. Many AMD patients have faulty genes that result in over activation of the immune system. Certain diets and  stress, further fuels the flames of inflammation and this can lead to even earlier onset of symptoms. In our laboratory at the University of Southampton, we measure the levels of inflammation in blood and eyes of AMD patients and compare the levels to healthy individuals. We hope to find a protein that can predict future vision loss, or inform us about novel ways to treat this debilitating disease. We may be able delay the symptoms of AMD if we control the immune system.

- Jessica L. Teeling, Professor of Experimental Neuroimmunology