An In Vitro Small Intestine Model Incorporating a Food Matrix and Bacterial Mock Community for Intestinal Function...

Area of Science:

• Gastroenterology
• Nanotechnology
• Microbiology

Background:

• The small intestine harbors a complex interplay between diet and microbiota.
• Food additives like titanium dioxide nanoparticles (TiO2 NPs) are common, necessitating an understanding of their biological impact.
• Existing models often lack the complexity to fully represent in vivo conditions.

Purpose of the Study:

• To develop and utilize a sophisticated in vitro model of the human small intestine.
• To investigate the effects of TiO2 NPs on intestinal epithelial function and nutrient transport.
• To explore the influence of a representative bacterial community on these interactions.

Main Methods:

• Establishment of a complex in vitro small intestinal model using human cells, simulated digestion, and a defined bacterial community (E. coli, L. rhamnosus, S. salivarius, B. bifidum, E. faecalis).
• Exposure of the model to physiologically relevant concentrations of TiO2 NPs.
• Assessment of epithelial permeability, alkaline phosphatase activity, triglyceride transport, and glucose transport.
• Evaluation of bacterial entrapment within the mucus layer.

Main Results:

• TiO2 NPs did not alter intestinal permeability but increased triglyceride transport in the absence of bacteria.
• The presence of the bacterial community reversed the TiO2 NP-induced increase in triglyceride transport.
• While individual bacterial species had no effect, the bacterial community enhanced glucose transport.
• TiO2 NPs exposure led to reduced bacterial entrapment in the mucus layer, potentially due to decreased mucus thickness.

Conclusions:

• The developed in vitro model effectively simulates small intestinal function, including host-microbiota interactions.
• TiO2 NPs at relevant concentrations do not compromise intestinal barrier integrity but can influence nutrient absorption dynamics.
• Bacterial communities play a crucial role in modulating the effects of food additives on nutrient transport and may exhibit community-specific behaviors.
• This model offers a valuable platform for studying the impact of nutritional components and nanoparticles on small intestinal physiology and the gut microbiota.