The use and validation of functional cell-based models of untransformed cell cultures for the assessment of risks and biological activity in biomedical research

Cell culture models of untransformed human tissues can be used to mimic the in vivo environment and to supplement as well as to upgrade current conventional pre-clinical protocols. Their applicability ranges from mechanistic and toxicological studies to the discovery of new drug targets. Therefore and also due to increased legal restrains for animal experimentation, we´ve accepted the 3R principle that strives to replace, reduce and refine animal models by creating reliable alternatives. In our work we aimed to develop, evaluate and validate new cell models based on untransformed cell cultures of the small intestinal epithelium, macrophages and skeletal muscle, cultured as monolayer models for high throughput research or advanced 3D models for deeper mechanistic studies. We have used untransformed small intestinal epithelial cells for the risk assessment of potentially pathogenic strains of B. cereus and further combined the culture with macrophages in a 3D model of the developing small intestine to evaluate the immunomodulatory properties of lactic acid bacteria. Since the gut functions as a primary interaction point for nutrients, microorganisms and xenobiotics we added a secondary organ system, namely skeletal muscle stem cells that we have used to assess the muscle regenerative potential of new therapeutics by utilizing state-of-the-art imaging flow cytometry. The models have been validated by comparison of our results with results obtained from animal studies and by showing functionality of isolated cell cultures. Our work enabled us to propose several new alternatives to genetically modified or cancer derived transformed cell cultures as well as animal models that might deliver more reliable results and reduce the number of sacrificed animals.