Amino acids suppress apoptosis induced by sodium laurate, an absorption enhancer.

The formulation containing sodium laurate (C12), an absorption enhancer, and several amino acids such as taurine (Tau) and L-glutamine (L-Gln) is a promising preparation that can safely improve the intestinal absorption of poorly absorbable drugs. The safety for intestinal mucosa is achieved because the amino acids prevent C12 from causing mucosal damages via several mechanisms. In the present study, the possible involvement of apoptosis, programmed cell death, in mucosal damages caused by C12 and cytoprotection by amino acids was examined.

Involvement of intracellular Ca2+ dynamics in cytoprotective action by amino acids and cytotoxicity by sodium laurate, an absorption enhancer.

In our previous studies, taurine (Tau) and L-glutamine protected intestinal epithelial cells from local toxicity caused by sodium laurate (C12), an absorption enhancer, while maintaining sufficient absorption-enhancing effect of C12, and it was suggested that one of the mechanisms behind cytoprotection by amino acids was to prevent intracellular Ca2+ concentration ([Ca2+]i) from increasing. In the present study, we focused on the elucidation of mechanisms by which C12 increases [Ca2+]i and by which amino acids suppress [Ca2+]i by utilizing Caco-2 cells. Removal of extracellular Ca2+ remarkably suppressed the increase of [Ca2+]i by C12.