SHIME® and M-SHIME®
The SHIME® is a unique scientifically validated dynamic model of the complete gastrointestinal tract to study physicochemical, enzymatic and microbial parameters in the gastrointestinal tract in a controlled in vitro setting. The model consists of five reactors which sequentially simulate the stomach (acid conditions and pepsin digestion), small intestine (digestive processes) and the 3 regions of the large intestine, i.e. the ascending, transverse and descending colon (microbial processes). Careful control of the environmental parameters in these reactors allows to obtain complex and stable microbial communities which are highly similar in both structure and function to the microbial community in the different regions of the human colon. The model can be used to study the metabolic fate of food, microbial and pharmaceuticals compounds over a period of several weeks.
A recent evolution of the SHIME® is the TWINSHIME®, in which two SHIME® systems are run in parallel, and where all the environmental parameters are completely identical. This allows to perform placebo-controlled in vitro studies or the direct comparison of the intestinal fate of two
products under identical conditions without interference of external parameters.
As compared with other GI simulators the SHIME® is unique in the following
- The complete gastrointestinal tract is simulated, from stomach to descending colon.
- Easy sampling of all regions allows to generate detailed mechanistic information on the intestinal fate of study compounds, such as factors affecting the bioavailability of active compounds (e.g. formulation or matrix effects), metabolic/fermentative processes which affect the structure or nature of active compounds and local activity profiles in the gastrointestinal tract.
- The specific setup of the SHIME® allows to perform long-term experiments (up to several months) with a stable, in vitro-adapted microbial community and using physiologically relevant product doses.
- The possibility of sampling big volumes from each colon area allows to perform parallel analyses without impacting the resident microbial community.
Intestinal bacteria are largely present in the intestinal lumen, yet a fraction of the microorganisms in the gastrointestinal tract can also selectively adhere to the mucus layer that covers the gut wall. To evaluate this fraction of bacteria, which are supposed to have a key role in human health as they live in very close contact with the host, ProDigest makes use of the of the M-SHIME® (Mucus-SHIME). In this model, a mucosal compartment is integrated in the colonic regions of the SHIME®, allowing the microbiota to adhere to the gut mucus layer under representative conditions.
These adhering bacteria play an important role as a ‘barrier’ against pathogens, by instructing mucosal immune responses and occupying a niche at the expense of potentially harmful colonizers. The evaluation of changes in bacterial adhesion due to, for instance, a prebiotic treatment or the specific adhesion capacity of probiotic strains is therefore a crucial step to study host-microbiota interactions and resulting health effects.