Scientific Publications
Transport of Particles in Intestinal Mucus under Simulated Infant and Adult Physiological Conditions: Impact of Mucus Structure and Extracellular DNA.
PLOS ONE, 9, e95274
The final boundary between digested food and the cells that take up nutrients in the small intestine is a protective layer of mucus. While allowing passage of nutrients, the mucus must also serve as an effective barrier to pathogens. These contrasting properties derive from microstructural organization of the mucus, which is still poorly understood. Moreover, the structure can also mature with age driven by exposure to a number of environmental factors such as colonization by microbiota, changes in diet, variations in the enzymatic activity of the intestinal secretion etc. In this work, the microstructural organization and permeability of the intestinal mucus have been determined under conditions simulating those of infant and adult human small intestines. As a model, we used the mucus from the proximal (jejunum) small intestines of piglets and adult pigs. Confocal microscopy of both unfixed and fixed mucosal tissue showed mucus lining the entire jejunal epithelium. The mucus contained DNA from shed epithelial cells at different stages of degradation, with higher amounts of DNA found in the adult pig. The pig mucus comprised a coherent network of mucin and DNA with higher viscosity than the more heterogeneous piglet mucus, which resulted in increased permeability of the latter to 500-nm and 1-µm latex beads. As revealed in multiple-particle tracking experiments, diffusion of the probe particles was considerably enhanced after treating mucus with DNase, which suggests that the extracellular DNA can significantly contribute to the microrheology and barrier properties of the intestinal mucus layer. This effect was observed in both pig and piglet mucus samples. The results may help to define rules governing colloidal transport in the intestine, which is required for engineering orally administered pharmaceutical preparations with improved drug delivery, as well as for fabricating novel foods with enhanced nutritional quality or for controlled calorie uptake.
PLOS ONE, 9, e95274
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