Role of gut microbiome in radiation-induced gastrointestinal injury

Abstract

Abstract of thesis entitled “Role of Gut Microbiome in Radiation-Induced Gastrointestinal Injury” Submitted by CHEUNG Jamie for the degree of Master of Philosophy at The University of Hong Kong November 2019 Acute radiation syndrome is commonly experienced by cancer patients received radiation therapy. Gastrointestinal tract as a highly proliferative organ is severely damaged, leading to nausea, vomiting, diarrhea and malabsorption of nutrients. Hence, weight loss is resulted. Radiation alters the composition and reduces the abundance of gut microbiota. Gut microbiota are trillions of symbiotic microorganisms inhabiting in the gastrointestinal tract. Gut microbiota helps maintaining the intestinal integrity and promotes nutrients uptake. Other than radiation, gut microbiota could be influenced by diets, xenobiotics and environments etc. Recent studies suggest diet could change the gut microbiome reversibly in as short as one single day. Current dietary guidelines recommend radiation-treated patients to consume a high calorie diet to increase energy intake to combat the malabsorption. However, molecular mechanisms of which macronutrient; such as, fats, proteins, or carbohydrates, is preferred are lacking. Fat provides the highest number of calories, but long-term high fat diet is not preferred as it causes chronic conditions, such as metabolic syndrome, diabetes and cardiovascular diseases. On the other hand, short term high fat diet could potentially upregulate gut microbiota that absorbs fat, so it is worth investigating. Generally, this study offers an insight in how gut microbiome altered by short term high fat diet provides protective effects against radiation-induced acute gastrointestinal toxicity. Mice received fecal microbiota transplantation from donors fed a three-week high fat diet showed reduced DNA damages and apoptosis rate after radiation treatment. (Count: 236 words)