Bioengineering approaches to simulate human colon microbiome ecosystem

Background Several diseases associated to colon microbial imbalance (dysbiosis), such as obesity, diabetes, inflammatory bowel disease, cardiovascular disease and cancer, are being reverted by modulation of gut microbiota composition through treatment with prebiotics and probiotics. Multiple in vitro models have been developed over the past three decades, with several experimental configurations, as they provide a quick, easy, and cost-effective approach to study the gut microbiome, as compared to troublesome and time-consuming in vivo studies. Scope and approach This review aims to provide an overview of the most relevant available in vitro models used to mimic the human colon microbiome dynamics, including macro-scale and microfluidic-based models. Main characteristics, functionalities, current applications and advantages or disadvantages of the models are discussed in order to provide useful information for end users (namely food and pharmaceutical researchers), when selecting the most appropriated model for assessing health claims and safety of novel functional food and drugs. Finally, the use of these colon models as a tool to study prebiotic and probiotic response in host-microbiota interaction is reviewed. Key findings and conclusions A wide range of in vitro models representing specific colon parts have been developed. However, none of these models can simultaneously cover all the key conditions found in the human colon (namely anatomical, physical, biochemical, and biological characteristics), as well as the complex microbiome-host interaction. Thus, there is a significant opportunity for further improvement of the models experimental setups towards more realistic operating systems, including mucosal surfaces, intestinal cells and tissues allowing microbiomehost crosstalk representation.SFRH/BD/139884/2018 from the Portuguese Foundation for Science and Technology (FCT). This study was supported by the FCT under the scope of the strategic funding of UIDB/04469/2020 unit and the Project ColOsH PTDC/BTM–SAL/30071/2017 (POCI–01–0145–FEDER–030071)