EFFECT OF HUMAN LACTOFERRIN (hLF) AND EPIDERMAL GROWTH FACTOR (hEGF) ON CACO-2 CELL MONOLAYER BARRIER FUNCTION

80 (Background & Aim) Development of epithelial barrier function in G-I tract is crucial to prevent harmful macromolecules from entering into the body. Biologically active substances in breast milk may play roles in developing the mucosal barrier function. Effect of hLF and hEGF, both known as human milk derived growth modulators for intestinal epithelial cells, on mucosal barrier function was examined using Caco-2 cell monolayer as a study model. (Methods) Caco-2 cells were cultured on permeable membrane filter in DMEM supplemented with 10% FCS for about 2 weeks. Culture media were then changed to serum free DMEM containing into-saturated and unsaturated hLf (50ug/ml), or hEGF (50ng/ml). Barrier function was evaluated by measuring transepithelial electrical resistance (TEER : Ohm·cm2) and fluorescent substance clearance (transport rate of fluorescein sulfonate [FS : MW478] and FITC-dextran[FD-4 : mean MW4400] from apical to basolateral side: nL/hr/cm 2). (Results) (1) Iron-saturated hLf showed significantly higher TEER than the control, while iron-unsaturated form did no effect. (2) The increase in TEER by iron-saturated hLf was dose-dependent. (3) Basolateral application of iron-saturated hLf was necessary to show the effect. (4) hEGF markedly reduced TEER, almost 50% of the control. (5) Significant reduction in FS and FD-4 clearances were observed in iron-saturated hLf treated cells compared to the control and iron-unsaturated Lf. (Table)(Conclusions) Iron-saturated human lactoferrin, acting from the basolateral side, enhanced Caco-2 cell monolayer barrier function in a dose-dependent manner, while human EGF reduced it. Bioactive substances in breast milk play important roles in developing intestinal barrier.Table