Protection effect of lutein-loaded Pickering emulsion prepared via ultrasound-assisted Maillard reaction conjugates on dry age-related macular degeneration

Age-related macular degeneration (AMD) is a prominent cause of vision loss among the elderly, and the treatment options for dry AMD (dAMD) are severely limited. Lutein has a favorable effect on the treatment of dAMD. Algae oil, rich in docosahexaenoic acid (DHA), is considered an effective intervention for eye diseases. In this study, casein-mannose conjugates were prepared to form algal oil-in-water Pickering emulsions by ultrasound-assisted Maillard reaction. As the ultrasound time increased from 0 to 25 min, the droplet size decreased to 648.2 ± 21.18 nm, which substantially improved the stability of the Pickering emulsions. The retention of lutein in the Pickering emulsions under ultrasonic treatment for 20 min was significantly improved under different conditions. The simulated gastrointestinal digestion revealed that ultrasound-assisted Pickering emulsions are an effective method for improving the bioaccessibility of lutein (19.76%-53.34%). In vivo studies elucidated that the lutein-loaded Pickering emulsions could effectively alleviate retinal thinning induced by sodium iodate (NaIO₃) in mice with dAMD. Mechanistically, lutein-loaded Pickering emulsions significantly reduced oxidative stress by decreasing the MDA level, increasing the SOD production, and reducing the retinal ROS production. These findings explored the protective effects of lutein-loaded Pickering emulsions on dAMD and offered promising prospects for the nutritional intervention of dAMD.