Selective Targeting of Senescent FHs74Int Cells by Human Breast Milk Free Fatty Acids

Cellular senescence is a state of irreversible growth arrest characterized by a pro-inflammatory phenotype, playing dual roles in development. In the fetal intestine, the regulation of senescent cells is critical for maintaining tissue homeostasis. Human breast milk (HBM), known for its rich composition of bioactive molecules, may play a role in modulating senescence, although its effects on senescent intestinal cells remain unexplored. This study investigated whether HBM selectively eliminates senescent cells in the FHs74Int fetal intestinal epithelial cell line. Senescence was assessed via β-galactosidase activity and expression of p16 and p21. The model cell line was treated with HBM, infant formula, and milk fractions, and outcomes included cell recovery, senescence markers, apoptosis, and mitochondrial potential. Total free fatty acids (FFA) were quantified and correlated with senolytic activity. HBM reduced senescent cell recovery without affecting non-senescent cells, correlating with decreased β-galactosidase activity, reduced phospho-p38 and γH2AX expression, mitochondrial depolarization, and caspase activation. Only the lipid fraction retained senolytic activity, which was associated with elevated FFA levels. Incubation of HBM at 37 °C increased FFA content and conferred senolytic activity. These findings are consistent with the idea that HBM exerts selective senolytic effects via FFA, revealing a novel mechanism by which breast milk could contribute to intestinal homeostasis.