Alternatives to animal models in gastroenterology and hepatology research

The accurate definition of in vivo , ex vivo and in vitro models is critical for the whole R&D process, i.e., basic research, clinical translation and reliability of results. Although many models are currently being developed, it is important to recognize the limitations and advantages of each of them. The aim of this review is to compile the most important alternatives to animal models in the fields of gastroenterology and hepatology research. A thorough comparison and understanding of each alternative model will certainly save time and money and will lead to better predictability and reliability of results for clinical translation and clinical trials. There is no single model capable of replacing the complexity of human biology. Nevertheless, it is essential to understand the fundamentals of human anatomy, physiology and disease pathophysiology to select the most appropriate model in translational research. At the same time, the appropriate model must be selected to gain a deeper understanding of the principal processes underlying human physiology and the pathology of diseases.