In vitro intestinal barrier model development and application for electrolyte absorption studies

Abstract

Introduction. The human intestine is a dynamic barrier that has an important role in the absorption of essential nutrients, water, electrolytes and vitamins [1,2]. Every day from 100 to 800 mmol of sodium (Na+), chloride (Cl−), and potassium (K+) pass through the intestinal lumen [3]. The electrolyte absorption disorders may underlie important diseases, and in vitro models made from human intestinal cells can help to better understand mechanisms involved in electrolyte absorption processes. Aim. To create human intestine in vitro model from human intestinal epithelial cell line, that replicates intestinal barrier function, and apply it to electrolyte absorption studies. Materials and Methods. The immortalized human colon epithelial cells HCEC-1CT were grown in DMEM on cell culture inserts. The integrity of the in vitro intestinal barrier was monitored by transepithelial resistance (TEER) using voltmeter Millicell ERS-2. Nine electrolyte solutions (mineral content varying from 0,2 to 15 g/l) were diluted with cell medium at ratio 1:4 and applied on cells in the insert chamber. Cell metabolic activity was assessed using PrestoBlueTM after 4, 24, and 48 hours in a multimode microplate reader Infinite 200 Pro M Nano Plex. Electrolytes Na+, K+, Ca2+ and Mg2+ from the samples above and below the in vitro intestinal barrier were determined by inductively coupled plasma mass spectrometer ICP-MS NexION 300D. Results. The TEER values increased with each day after cell seeding, and the highest value of 179 •} 6,5 Ω cm2 were observed on day 7 of culture. The electrolyte solutions did not significantly affect HCEC-1CT cell metabolic activity after 4 h of incubation. However, the solutions of low mineralization (0,2 g/l, 0,7 g/l, 1 g/l of electrolytes) significantly decreased metabolic activity after 24 h, and the effect remained after 48 h. The electrolyte solutions of intermediate concentration (1,2 g/l, 1,6 g/l) sig[...].