BACKGROUND: Age-related macular degeneration (AMD) is driven in part by oxidative damage and inflammation, contributing 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 effect alongside current AREDS2 nutrients. This study compared the effects of AREDS2 components, B vitamins, and their combination on cytoprotection and gene expression in an iPSC-derived RPE AMD model.

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

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

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