Lutein-in-Extra-Virgin-Olive-Oil Supplementation as a Multifaceted Nutritional Intervention for Retinopathy of Prematurity: Evidence from the Mouse Oxygen-Induced Retinopathy Model

Background: Retinopathy of prematurity (ROP) is a predominant contributor to preventable childhood blindness driven by oxidative stress and inflammation, but with limited treatment options. Safe, non-invasive adjunctive strategies become attractive. Lutein displays antioxidant and anti-inflammatory properties, but its clinical efficacy remains controversial. We proposed that formulating lutein in extra-virgin olive oil (EVOO) might enhance its absorption and efficacy in ROP. Here, we evaluated the effects of lutein-in-EVOO (LEVOO) in oxygen-induced retinopathy (OIR), a mouse model of ROP. Methods: C57BL/6J mouse neonates received daily gavage of LEVOO (0.4 μg/g, 1.8 μg/g and 3.6 μg/g of lutein in EVOO) after OIR challenge from postnatal day (P) 12 to P16. Assessments were conducted at P17, including retinal vasculature, function, cytoarchitecture, inflammation, and oxidative damage; serum biochemical and antioxidant profiles; and proteomic analysis and targeted retinal metabolomic analysis. Results: Oral supplementation of LEVOO was well-tolerated and safe in mouse neonates. It reduced retinal avascular and neovascular areas, increased electroretinographic b-wave amplitudes, and restored amacrine cells and rod bipolar cells. LEVOO administration reduced oxidative damage and activated microglia. LEVOO administration inhibited the hypoxia-inducible factor-1α (HIF-1α)/macrophage migration inhibitory factor (MIF) signaling and low-density lipoprotein receptor-related protein-1 (LRP1)-dependent cyclophilin A (CypA)/matrix metalloproteinase-9 (MMP9) signaling. It also helped to partially restore retinal docosahexaenoic acid and dopamine in OIR mice. Conclusion: LEVOO demonstrated multifaceted efficacy in OIR. It reconstructed retinal vasculature, restored retinal function, and rescued neuronal cell loss with strong antioxidative and anti-inflammatory effects. Collectively, these findings establish LEVOO as a promising non-invasive complementary strategy for ROP.