Molecular Nutrition

Modification of an in vitro model simulating the whole digestive process to investigate cellular endpoints of chemoprevention

Katrin Stein^a1 c1, Anke Borowicki^a1, Daniel Scharlau^a1, Kerstin Scheu^a2, Gerald Brenner-Weiß^a2, Ursula Obst^a2, Jürgen Hollmann^a3, Meinolf Lindhauer^a3, Norbert Wachter^a4 and Michael Glei^a1

^a1 Department of Nutritional Toxicology, Institute for Nutrition, Friedrich-Schiller-University Jena, Dornburger Strasse 24, 07743 Jena, Germany

^a2 Department of Microbiology of Natural and Technical Interfaces, Research Center Karlsruhe, Institute of Functional Interfaces (IFG), Hermann-von-Helmholtz-Platz 1, 76344 Eggenstein-Leopoldshafen, Germany

^a3 Max Rubner-Institute, Federal Research Institute of Nutrition and Food, Schützenberg 12, 32756 Detmold, Germany

^a4 Kampffmeyer Food Innovation GmbH, Trettaustr. 32-34, 21107 Hamburg, Germany

Abstract

In vitro gut fermentation systems are relevant tools to study health benefits of foodstuffs. Most of them are commonly used to investigate the degradation of nutrients or the development of gut flora. Using these models, strong cytotoxic effects of the resulting samples on cultured cells were observed. Hence, the aim of the present study was to develop a modified in vitro fermentation model that simulates the whole digestive tract and generates fermented samples that are suitable for testing in cell culture experiments. Wholemeal wheat flour (wwf) was digested and fermented in vitro with a fermentation model using different ox gall concentrations (41·6 and 0·6 g/l). The resulting fermentation supernatants (fs) were characterised for metabolites and biological effects in HT29 cells. The fermentation of wwf increased chemopreventive SCFA and decreased carcinogenic deoxycholic acid (DCA). The strong cytotoxic effects of the fs, which were partly due to cholic acid and DCA, were diminished by lowering the ox gall concentration, allowing the use of the samples in cell culture experiments. In conclusion, an in vitro digestion model, which can be used to study the effects of foodstuffs on chemoprevention and gut health in colon cells, is introduced and its physiological relevance is demonstrated.

(Received May 19 2010)

(Revised September 23 2010)

(Accepted September 24 2010)

(Online publication January 28 2011)

Key Words:

• Chemoprevention;
• Deoxycholic acid;
• Fermentation;
• SCFA;
• Wheat

Correspondence:

^c1 Corresponding author: K. Stein, fax +49 3641949672, email stein.katrin@googlemail.com

Footnotes

Abbreviations: CA, cholic acid; DCA, deoxycholic CA; fs, fermentation supernatants; GIT, gastrointestinal tract; wwf, wholemeal wheat flour