This article has been reviewed according to Science X's editorial process and policies. Editors have highlighted the following attributes while ensuring the content's credibility: The intestines rely on different strategies to rebuild themselves in response to diet changes versus infections, according to a new Cornell study—a finding that can shed light on how gut health adapts to harsh conditions, flourishing ecosystems of microbes and variable diets. The findings, reported in Communications Biology, show that infectious damage causes cell loss and triggers stem cells to create new ones, while diet changes cause existing cells to grow or shrink.
"We want to understand the basic mechanisms of how stem cells respond to microbes and repair the gut because these findings will, we hope, ultimately help us address infections and diseases like Crohn's and cancer," said Nicolas Buchon, senior author of the paper and associate professor of entomology in the College of Agriculture and Life Sciences. "We may want to boost stem cell response to help with repair after a serious infection. Or we may want to limit stem cell proliferation if cells are responding aberrantly and building a tumor." Pharmaceuticals or therapeutics based on these findings are many years away, but basic discoveries like this one lay the foundation for future breakthroughs.
In 2009, Buchon and colleagues reported that when fruit flies were infected with the bacterium Erwinia carotovora (Ecc15), the microbes triggered an immune response and stem cell proliferation. The finding helped establish how microbes can connect an immune response to stem-cell-driven repair in the intestine. The current study also relies on fruit flies and Ecc15, but explores the interplay of infection and nutritional status at the same time.
Scientists studying the gut generally examine one factor or the other, and that division has led to very different assumptions about how the intestines adapt and rebuild, Buchon said. "If you study the gut from the perspective of nutrition, you can conclude that the gut is constantly shifting and adapting: Feed less, and the gut will shrink; eat more nutritious food, and it will expand," he said. "If you look at microbes and infection, the key word is always homeostasis.
That means if you damage the gut, it will rebuild to its former state. So our question was, well, which one is it? Can we manipulate food, manipulate microbes and play with the complete matrix to see how the gut responds to all of those stimuli at once?" In their experiments on fruit flies—a model organism frequently used by scientists to make discoveries in basic biology that apply to all multicellular organisms, including humans—they found that the consequences of an infection on the intestines depend on their initial health and size.
In a well-nourished organism, infection causes the intestine to shrink quickly and dramatically. In a malnourished organism, the already small intestine shrinks much less, and infectious microbes become a food source more than a threat. They also determined that the intestine rebuilt according to the nutritional environment in which recovery occurred.
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