Long term culture of epithelia in a continuous fluid gradient for biomaterial testing and tissue engineering

Abstract

Epithelia perform barrier functions being exposed to different fluids on the luminal and basal side. For long-term testing of new biomaterials as artificial basement membrane substitutes, it is important to simulate this fluid gradient. Individually-selected biomaterials can be placed in tissue carriers and in gradient containers, where different media are superfused. Epithelia growing on the tissue carriers form a physiological barrier during the whole culture period. Frequently however, pressure differences between the luminal and basal compartments occur. This is caused by a unilateral accumulation of gas bubbles in the container compartments resulting in tissue damage. Consequently, the occurence of gas bubbles has to be minimized. Air bubbles in the perfusion culture medium preferentially accumulate at sites where different materials come into contact. The first development is new screw caps for media bottles, specifically designed to allow fluid contact with only the tube and not the cap material. The second development is the separation of remaining gas bubbles from the liquid phase in the medium using newly-developed gas expander modules. By the application of these new tools, the yield of embryonic renal collecting duct epithelia with intact barrier function on a fragile natural support material can be significantly increased compared to earlier experiments.

Optimization of culture conditions for osteogenically-induced mesenchymal stem cells in β-tricalcium phosphate ceramics with large interconnected channels

“…It was shown that serum‐free media without further addition of growth factors are not capable of supporting the proliferation of MSCs (Berger et al , 2006) and that MSCs undergo apoptosis when subjected to hypoxia and serum deprivation (Zhu et al , 2006). However, as shown in the past, serum‐free and low‐serum conditions combined with perfusion culture were successful in the differentiation of epithelial cells (Minuth et al , 2001) and chondrocytes (Sittinger et al , 1997). Therefore, the investigation of low‐serum conditions compared to standard conditions seems to be useful for the study of perfusion culture.…”

Dietary salt intake modulates differential splicing of the Na-K-2Cl cotransporter NKCC2

“…Tissue culture was performed as described in detail recently (23,35). In brief, kidneys were harvested and cut with a tissue chopper.…”

Bioengineering of living renal membranes consisting of hierarchical, bioactive supramolecular meshes and human tubular cells

“…Fluctuations in glucose levels and electrolyte content, as well as the accumulation of waste products such as lactate, which frequently occur in static culture set-ups, can trigger dedifferentiation of renal epithelial cells [50,51]. Perfusion culture avoids these fluctuations and can be a critical factor for epithelial differentiation and function [52]. Accordingly, in our experimental set-up we also applied perfusion conditions.…”