A research grant of £110,951 has been awarded to Dr Alan Stewart and Dr Imre Lengyel (UCL Institute of Ophthalmology) from Fight for Sight to carry out a new 2-year study entitled “Identifying the hydroxyapatite interactome: clarifying the involvement of serum proteins in the formation of sub-retinal pigment epithelial (RPE) deposits”. A major feature of the ageing retina is the thickening of Bruch’s membrane and the formation of sub-retinal pigment epithelial (RPE) deposits that can block metabolic exchange between the choroidal blood circulation and the retina leading to sensory retinal degeneration and eventually to age-related macular degeneration (AMD), a major cause of visual impairment and blindess in older adults (>50 years). Recently, Thompson et al. reported the existence of small (0.5-20 μm diameter) protein-binding hydroxyapatite (HAP) spherules within sub-RPE deposits isolated from AMD-affected individuals (see link). This suggests that the spherules may provide nucleation sites for sub-RPE deposit formation, where the initiation, growth and retention of deposits are controlled by the binding of proteins present in the sub-RPE space to the spherules. In the funded study, HAP-binding proteins in the plasma of genotyped late-stage AMD patients will be isolated and quantitatively identified and biochemically characterised.