Developing eye drop treatment for diabetic retinopathy

Project background: why was the research important?

Diabetic retinopathy is the leading cause of blindness in the working age population of the UK. Some 750,000 people are believed to have “background diabetic retinopathy” which may eventually progress to total blindness.

Diabetes leads to high blood sugar levels, which causes blood vessels at the back of the eye to leak, become blocked, or grow haphazardly, damaging the retina. Currently, this problem can only be treated by regular injections into the eye. Many patients require monthly injections, and aside from being unpleasant, the treatment carries an accumulating risk of adverse side effects and can also become less effective over time.

What was the aim of the project?

In 2017, a successful appeal by Sight Research UK provided funding for a three-year project that allowed Professor David Bates and his team to develop their research into a highly promising new treatment for diabetic retinopathy.

They had already identified chemicals that could prevent blood vessels from leaking, and which could potentially be administered as eye drops, but further research and testing was needed before a drug could be developed for human trials.

The chemicals at the centre of the project work by inhibiting the production of a protein known as Vascular Endothelial Growth Factor (VEGF), which makes blood vessels become leaky and permeable, and also causes new blood vessels to form abnormally in the eye. The properties of the therapeutic chemicals allow them to build up in the outer part of the eye (the sclera), while they are slowly released into the inner layer, where the blood vessels leak as they grow into the back of the eye.

Professor Bates’ team wanted to determine whether these chemicals could prevent fluid leaking in the retinas of animals with diabetes, whether they were effective in targeting a gene called SRPK1, which regulates the production of the VEGF protein, and whether the chemical could prevent abnormal blood vessel growth.

What was the outcome?

Over the course of the project, the team found multiple pieces of evidence to show that blocking the effects of the gene, SRPK1, is a viable treatment for diabetic retinopathy. Targeting this gene with the drug SPHINX31, has been shown to reduce its activity and protect against diabetes-induced problems including leakiness in the eye, increases in eye permeability, and thickening of the retina.

How will this research help to beat sight loss faster?

Establishing drugs that work in the same way as SPHINX31, which can be administered as an eye-drop rather than direct injections into the eye, will deliver huge benefit. Firstly, to patients as the treatment will be more effective and convenient, and secondly to the health and social care system because eye drops are far less costly than injections.

The findings of this study are now the focus of a clinical trial testing the next generation of SRPK1 inhibitor in patients with macular oedema: a common complication of diabetic retinopathy.

Thank you

This research was made possible thanks to the £103,000 given so generously by our community of donors. In particular, we would like to thank the Masonic Charitable Foundation, the Robert McAlpine Foundation, the Bill Brown 1989 Charitable Trust and the Carman Butler Charteris Trust for their very significant contributions. We are also deeply grateful to all our individual supporters, whose donations large and small have contributed to fund the development of this highly promising new treatment.

Further information

You can learn more about the symptoms and current treatments for diabetic retinopathy here.