The study found that dietary fiber polymer molecules change what occurs in the intestinal microbe by combining large molecules together.
Large dietary fiber molecules, called polymers, can physically affect the environment in the small intestine by causing the solid particles to aggregate (or aggregate), according to research published in eLife.
A mouse study provides a new insight into how the various types of solid particles found in the small intestine – including microbes, cell trays, drug delivery particles and food granules – move together with the intestine. This is important because the size and composition of such aggregates could potentially affect the intestinal environment, including how nutrients and drug particles are absorbed during digestion.
"When particles in the form of intestinal aggregates can affect the intake of drugs and nutrients, as well as the function of microorganisms in the intestines, it is little understood how these aggregates form," said Asher Presko Steinberg, a chemist at the California Institute of Technology, Pasadena, USA.
The variety of polymers exists naturally in the intestine; contain secretions (such as torture and immunoglobulins) and dietary polymers, including dietary fiber. It is well known that host-secreted polymers can cause the aggregation of microbes by chemical bonding. This new paper, however, shows that fiber polymers can also cause aggregation through physical interactions that depend on the physical properties of the polymers, such as their molecular weight and concentration, instead of chemical interactions.
"We often think about dietary fiber in the context of nutrition and feeding our intestinal microbes, but like all polymers, we follow the laws of polymer physics." We wanted to find out if the physical forces induced by these polymers play a role in structuring the particles in the small intestine, "Presque Steinberg explained.
For this purpose, the group first studied interactions between polystyrene particles that were densely coated with polyethylene glycol (PEG) and mouse small intestine content. The PEG-coating has previously been used to minimize chemical interactions between particles and biopolymers, allowing the team to focus on the role of physical interactions. First, they found that PEG-coated particles commonly used in drug delivery are grouped together as aggregates in small intestine fluid.
Liquid analysis later showed that polymers actually contribute to the aggregation of PEG coated particles and that the extent of aggregation depends on the concentration of polymers and molecular weight.
It further carried out immunoglobulin and mucin assays, called MUC2, on PEG-coated particles. They found that although MUC2 may play a role in the aggregation of PEG coated particles, aggregation was not necessary.
"Instead, our results have suggested that aggregation can be controlled using fiber polymers that the mice consume," said senior scientist Rustem Ismagilov, Ethel Wilson Bowles, and Professor Robert Bowles of the California Institute of Technology. "What's more, this aggregation is adjustable. By feeding molecular fiber mice we found that we are able to control aggregation in their intestinal fluid."
"This previously undervalued role of polymeric fiber in the diet can also occur when aggregating other particles in the intestine and it will be important for us to investigate further," concludes Ismagilov.