Cholesterol-lowering eye drops could be used to treat a common cause of blindness, research suggests.
Scientists found a link between high cholesterol levels in immune system cells and age-related macular degeneration (AMD).
In experiments with mice, they were able to control the key cause of AMD with eye drops containing cholesterol-regulating agents.
AMD, the leading cause of blindness among older people in the Western world, occurs when the over-growth of blood vessels produce bleeding and scarring in the eye. Eventually, the central part of the eye responsible for fine-detail vision is destroyed.
Previous studies have shown that macrophages, white blood cells which form part of the immune system, play a key role in AMD. Macrophages promote the abnormal blood vessel growth linked to the condition, but it has not been clear how.
The new research shows that high levels of cholesterol building up in the macrophages block the normal inhibition of new blood vessels.
"Our increased understanding of cholesterol's role in the growth of ocular (eye) blood vessels helped us identify therapeutically modifiable pathways, opening up avenues for new treatments that may help us prevent blindness caused by macular degeneration," said Dr Rajendra Apte, from Washington University School of Medicine in the US.
Ageing mice were treated with two drugs designed to aid the transport of cholesterol out of the cells. They experienced a reduction in the growth of blood vessels in their eyes.
The findings, published in the journal Cell Metabolism, have implications that go beyond AMD, the researchers believe.
"Abnormal blood vessel growth is a characteristic of not only AMD, but also diverse disease processes outside the eye, including cancers and atherosclerosis, which are both associated with significant morbidity and mortality," said Dr Apte. "Our findings may have significant relevance in our understanding of the pathobiology of these conditions."