PURPOSE: Age-related macular degeneration (AMD) is driven in part by oxidative damage and inflammation, which contribute to progressive dysfunction of the retinal pigment epithelium (RPE) and neurosensory retina. The AREDS and AREDS2 formulations provide antioxidant and micronutrient support to slow disease progression; however, the potential additive benefits of B vitamins on RPE protection have not been evaluated. B vitamins regulate mitochondrial metabolism, homocysteine balance, and oxidative stress, suggesting a possible complementary and additive effect alongside current AREDS2 nutrients. This study compared the effects of AREDS2 components, B vitamins, or their combination on cytoprotection and gene expression in an iPSC-derived RPE AMD model.

METHODS: Human iPSC-derived RPE cells from donors carrying high-risk AMD alleles (ARMS2/HTRA1) were treated with N-retinyl-N-retinylidene ethanolamine (A2E) and blue light to model AMD after pretreatment with AREDS2 components, B vitamins, or their combination. Cell viability was evaluated using CellROX assays. Transcriptomic changes were assessed by bulk RNA sequencing, and differential gene expression (DESeq2) was analyzed for Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway enrichment.

RESULTS: Exposure to either AREDS2 components alone or the combination of AREDS2 components and B vitamins significantly improved cell viability in this iPSC-RPE AMD model. Distinct gene expression profiles were observed following exposure to AREDS2 components versus the combined treatment, including additional pathways associated with antioxidant defense and overall RPE health, suggesting enhanced stress adaptation and cellular recovery capacity.

CONCLUSIONS: Although exposure to B vitamins alone did not significantly improve cell viability or drive notable changes in gene expression, their combination with AREDS2 components was protective in this in vitro AMD model. The combined treatment also elicited additional gene expression changes related to oxidative stress and RPE survival pathways compared with exposure to AREDS2 components alone, suggesting a potential additive or synergistic effect.