Exploring the potential of red-light phototherapy as a treatment for age-related macular degeneration

Grant holder: Dr Elinor Thompson,
Institution: University of Greenwich
Grant award: £10,000
Start date: July 2020
End date: June 2022

Photo credit: Marcus Ginns

Why is this research needed?

Age related macular degeneration (AMD) is currently the leading cause of severe and permanent sight loss in the UK, and in the developed world. This progressive disease damages the macular: the part of the eye that is responsible for our central, detailed, and much of our colour vision. A poor understanding of exactly what causes the macula to become damaged means that AMD is currently incurable. While treatments exist for the wet form of the disease, there is still no treatment for the most common form: dry AMD.

Cell damage is part of the normal ageing process and it is known to be linked to age related diseases when problems build up in the mitochondria: the energy-producing compartments of cells. Mitochondrial damage in the retina has been linked to the progression of AMD, but the process through which mitochondrial decline leads to disease is not yet understood. Recent studies have shown that red-light phototherapy can improve mitochondrial function but again, exactly how it does so is unknown.

Why are mitochondria important in AMD?

You can think of mitochondria as a cell's power station that produces the energy for it to carry out all its functions properly. They work in a similar way to a digestive system: they take in nutrients and generate energy by breaking them down. This process is called cellular respiration and mitochondria use oxygen to release energy to the cell.

With ageing, or disease, however, mitochondria have been shown to perform their digestive function less well, which, in the eye, can lead to inflammation in the retina. Inflammation is known to be correlated with AMD, therefore declining mitochondrial function in the retina is an important marker of potential susceptibility to AMD.

What is the aim of the project?

Dr Thompson’s background in microbiology gives her a helpful perspective on developing this potential treatment by allowing research to be done on evolutionary similar systems, without the need for retina tissues. In collaboration with researchers from UCL’s Institute of Ophthalmology, she has studied how mitochondria taken from the cells of flies, mice, and humans respond to red-light phototherapy compared with how mitochondria taken from more basic organisms, such as nematodes and amoebae, respond when exposed to the same treatment.

This work is identifying common responses in the underlying cellular machinery between all the subjects to investigate the extent to which the evolutionary red-light response extends into simpler organisms.

How will this research help to beat sight loss faster?

Dr Thompson now plans to use simple model organisms to show how mitochondrial response to phototherapy might help to treat AMD. This will allow her to:

develop systems with which it is easier, more ethical, and more cost effective to run experiments
identify markers that can be used in multiple experiments to measure biochemical and genetic responses to red-light phototherapy;
uncover fundamental new knowledge essential to the advancement of this new treatment.

Beyond the scope of this project, improved knowledge of red-light response will help to cast light on the potential of phototherapy to treat other eye diseases such as glaucoma, macular dystrophy, and retinal ageing.

Further information

You can find more about the causes and symptoms of AMD here.

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