Interactions between hydroxyapatite and cholesterol associated with calcification in age-related macular degeneration.

Hydroxyapatite deposition and calcification occurs over cholesterol-containing lipid droplets between Bruch's membrane and sub-retinal pigment epithelium (sub - RPE) in the eyes of patients affected by age-related macular degeneration (AMD) as spherules, nodules, and Bruch's membrane plaques. In the present study, an attempt has been made to prepare a composite containing hydroxyapatite and cholesterol to elucidate interactions involved in the formation of such organic-inorganic interphase. To understand the mechanism of hydroxyapatite deposition on cholesterol, we have applied various biophysical techniques such as dynamic light scattering (DLS) measurements, transmission electron microscopy (TEM) imaging, Fourier transform infrared (FTIR) spectroscopy and solid-state nuclear magnetic resonance (ssNMR) spectroscopy on the prepared composite. Our results give molecular level insight into the mechanism of biocalcification in the disease system.