Age-related macular degeneration (AMD) is a major cause of blindness, especially in older adults. A key feature of early AMD is the formation of drusen, clumps of debris made of lipids and proteins that collect between two layers at the back of the eye — the retinal pigment epithelium (RPE) and Bruch’s membrane (BrM).
These drusen are not just signs of the disease; they actively contribute to vision loss by damaging the retina above them. Scientists suspect that lipoproteins — fat-protein complexes like high density lipoprotein (HDL) — play a big role in forming drusen. However, it wasn’t clear why these lipoproteins get stuck in BrM in the first place.
This study, published today in Proceedings of the National Academy of Sciences ( PNAS ) and led by Christopher B. Toomey , M.D., Ph.D., an assistant professor of ophthalmology at the Shiley Eye Institute, Viterbi Family Department of Ophthalmology, UC San Diego School of Medicine, suggests that heparan sulfate (HS) in BrM is a major player in early AMD by trapping lipoproteins and kickstarting drusen formation. Targeting this sticky interaction might be a way to prevent or even reverse early signs of AMD before vision loss occurs.
Findings of the study:
The study also shows the promise of non-blood-thinning forms of heparin as potential treatments. These could help “wash away” harmful lipids without the bleeding risks of regular heparin.
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Proceedings of the National Academy of Sciences