Age-related Macular Degeneration (AMD) is one of the most common causes of sight loss in adults. Thanks to long-term support from Fight for Sight, Prof Heping Xu’s and Dr Mei Chen’s lab discoveries could one day slow down AMD.
Age-related macular degeneration (AMD) is one of the most common causes of visual impairment in the over 60s. Obstruction of and damage to the macula – a key part of the retina – leads to a person’s central vision worsening over time.
In the later stages, it can develop into ‘wet’ AMD, where sight loss is caused by blood vessels growing across the macula, and in some cases, permanent scarring called macular fibrosis. Alternatively, in ‘dry’ AMD, the retinal pigment epithelial cells which support and nourish the photoreceptors start to die.
The immune system and AMD
Prof Heping Xu and Dr Mei Chen lead research groups at Queen’s University Belfast, and were awarded their first joint Fight For Sight-funded project in 2011.
That project was based on the idea that AMD resulted from an imbalance in the eye in older age: between the damage caused to the retina over time, and the reduced ability of the immune system to repair this damage.
Since then, Heping and Mei have been awarded several grants between them from Fight For Sight to study the role of the immune system in AMD. The two focal points of this work have been immune cells called macrophages, and the complement system – a mechanism which supports other parts of the immune response.
They’ve discovered the complement system may convert macrophages and retinal pigment epithelial cells into myofibroblasts, which contribute towards macular fibrosis.
“When you talk to Fight for Sight supporters, they do understand all the ways that it takes a long, long time to develop the drug for some diseases.
“But when you tell them what progress you’ve made in your research, they are excited, they feel that money they invested perhaps will someday make a difference to patients.”
From the lab bench to the clinic
Recently, Heping and Mei have made important findings about the role that the complement system plays in macular fibrosis – the permanent, irreversible scarring that happens in some cases of wet AMD. Crucially, they’ve shown in animal models that blocking a part of the complement system can significantly reduce this scarring.
Existing ‘complement inhibitor’ drugs are in clinical trials for dry AMD. Based upon their research, Heping and Mei believe these drugs could be repurposed for treating wet AMD and macular fibrosis.
So, while they continue their basic research, they’re also making sure their lab discoveries make a difference to patients. “We’re engaging a lot more with industry [and with] clinicians to try to verify some of the key targets that we discovered, in patient cohorts,” says Heping.
The key role of Fight For Sight
Heping and Mei agree that the funding from Fight For Sight has been critical to the success of their combined research programme. In a field that doesn’t have a lot of dedicated funding for basic research, Fight for Sight’s support has been invaluable.
And because of this, they have been successful in applying for grants from other funders. What’s more, their reputation has attracted visiting scholars and researchers to Belfast from across the world.
Mei is clear that without that support, she simply would not be doing the research she is doing today. “If I could use one sentence to say how I feel about what Fight for Sight has done for me and my career, I would say that ‘without Fight for Sight, [you wouldn’t have] me’.”
“The Fight for Sight funding allowed us to do the research and build up our reputation. And as a consequence of that, we’re able to attract researchers and students from different parts of the world to visit us and to come to learn from us.”
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