Cellular Stress, Inflammation and Barrier Damage in Gut Epithelial Cells Caused by Aspartame

Aspartame has been widely used as a sweetener in foods and beverages since the 1980s. In this study, we aimed to assess its effects on gut epithelial cell biology, inflammation and the epithelial barrier. We found that aspartame induces cytotoxic effects, disrupts the epithelial barrier and triggers proinflammatory cytokine release in gastrointestinal epithelial cells, organoids and gut-on-a-chip models at concentrations corresponding to daily consumed doses in food products. Cellular cytotoxicity was observed at doses as low as 1.25 mg/mL. RNA sequencing analysis revealed that aspartame significantly alters the transcriptome in gut-on-a-chip models, with upregulation of pathways involved in the unfolded protein response, pro-apoptotic and inflammatory processes and downregulation of those related to DNA repair and replication. Aspartame exposure upregulated proinflammatory genes, particularly in the TNF signalling pathway, and induced multiple chemokine responses. It also activated the NF-κB pathway via oxidative stress, promoting inflammation in NF-κB reporter monocyte cells and leading to gut epithelial cell death. Additionally, aspartame affected genes involved in tight and adherens junctions, disrupting gut epithelial barrier integrity in a dose-dependent manner. It further suppressed key DNA repair and replication genes associated with double-strand break repair, mismatch repair and DNA replication. Overall, our findings indicate that, at commonly consumed levels, aspartame induces cellular stress, inflammation and epithelial barrier damage in gastrointestinal epithelial cells. These results underscore the biological relevance of our study and raise concerns that daily dietary intake of aspartame may pose previously underappreciated risks to gut health.