Evaluation of calcium depletion as a strategy for enhancement of mucosal absorption of macromolecules

► Apical calcium removal produces a modest effect on epithelial tight junctions (TJ). ► Following an initial depletion, apical calcium level recovers. ► Prolonged apical calcium exhaustion exhibits a larger, but moderate effect on TJ. ► Basolateral calcium depletion leads to notably large effect on TJ. ► Polyacrylic acid does not alter basolateral calcium and modestly affects TJ.