Effects of Alphitobius diaperinus and Tenebrio molitor Larvae Digestates on Intestinal Epithelial Barrier and Antioxidant-Related Gene Expression in Differentiated Caco-2 Cells: An In Vitro Study

Edible insects have drawn increasing interest from researchers as sustainable sources of protein with potential functional ingredients for feed and food applications. However, the intestinal effects of digestion-derived fractions remain insufficiently characterized. The present research combined INFOGEST 2.0 in vitro digestion with a polarized Caco-2 monolayer model to examine the potential intestinal effects of digestates produced from Tenebrio molitor and Alphitobius diaperinus. Neither digestate affected cell viability at the tested concentrations. Transepithelial electrical resistance also remained comparable to the control treatments, indicating the preservation of monolayer integrity. Nevertheless, both insect-derived digestates moderately increased Lucifer Yellow apparent permeability. At the molecular level, both treatments significantly upregulated genes associated with epithelial differentiation and tight junctions, including claudins and intestinal alkaline phosphatase, while A. diaperinus digestate additionally increased the mRNA expression of tight junction protein 1 and sucrase-isomaltase. Both digestates also enhanced the expression of antioxidant-related genes, including NAD(P)H quinone dehydrogenase 1, glutathione-disulfide reductase, and heme oxygenase 1, with A. diaperinus eliciting a broader transcriptional response than T. molitor by additionally increasing the expression of NFE2-like bZIP transcription factor 2 and superoxide dismutase 1. Overall, these results indicate that digestion-derived components from these edible insects can modulate selected intestinal epithelial and antioxidant-related transcriptional responses in differentiated Caco-2 cells under the conditions tested.