Radiation enteropathy and microbiota

The use of radiation therapy to treat pelvic and abdominal cancers can lead to the development of either acute or chronic radiation enteropathy. Radiation-induced chronic colonic fibrosis is a common gastrointestinal disorder resulting from the above radiation therapy. In this study, we establish the efficacy of inulin supplements in safeguarding against colonic fibrosis caused by irradiation therapy. Studies have demonstrated that inulin supplements enhance the proliferation of bacteria responsible to produce short-chain fatty acids (SCFAs) and elevate the levels of SCFAs in feces...

The effect of ionizing radiation on the gastrointestinal tract is a common complication of abdominal and pelvic radiotherapy. However, the pathological features of radiation enteropathy and its effective medical intervention regimen is still a global challenge. Here, we explored the role and mechanism of enteric alpha-defensins (EαDs) in protecting against radiation enteropathy. To address this, we utilized EαDs-deficiency mice, in which the matrix metallopeptidase 7 to activate Paneth cell α-defensins was knockout (KO) mice, and the complementary wild-type (WT) control mice for this study...

Approximately 60-80% of cancer patients treated with abdominopelvic radiotherapy suffer post-radiotherapy toxicities including radiation enteropathy and myelosuppression. Effective preventive and therapeutic strategies are lacking for such radiation injury. The gut microbiota holds high investigational value for deepening our understanding of the pathogenesis of radiation injury, especially radiation enteropathy which resembles inflammatory bowel disease pathophysiology and for facilitating personalized medicine by providing safer therapies tailored for cancer patients...

The human gut microbiome plays a key role in regulating host physiology. In a stable state, both the microbiota and the gut work synergistically. The overall homeostasis of the intestinal flora can be affected by multiple factors, including disease states and the treatments given for those diseases. In this review, we examine the relatively well-characterised abnormalities that develop in the microbiome in idiopathic inflammatory bowel disease, and compare and contrast them to those that are found in radiation enteropathy...

Pelvic cancer radiotherapy may cause chronic radiation proctitis (CRP) that adversely affects patient's quality of life, especially in patients with prolonged hematochezia. However, previous studies of radiation enteropathy mainly focused on acute irradiation hazards, and the detailed pathogenesis process and mechanism of prolonged hematochezia associated with radiation-induced toxicity remain unclear. In this study, we characterized the gut microbiota of 32 female CRP patients with or without hematochezia...

An ever-growing body of evidence has linked the gut microbiome with both the effectiveness and the toxicity of cancer therapies. Radiotherapy is an effective way to treat tumors, although large variations exist among patients in tumor radio-responsiveness and in the incidence and severity of radiotherapy-induced side effects. Relatively little is known about whether and how the microbiome regulates the response to radiotherapy. Gut microbiota may be an important player in modulating "hot" versus "cold" tumor microenvironment, ultimately affecting treatment efficacy...

PURPOSE: Radiotherapy is important in managing pelvic cancers. However, radiation enteropathy may occur and can be dose limiting. The gut microbiota may contribute to the pathogenesis of radiation enteropathy. We hypothesized that the microbiome differs between patients with and without radiation enteropathy. Experimental Design: Three cohorts of patients ( n = 134) were recruited. The early cohort ( n = 32) was followed sequentially up to 12 months post-radiotherapy to assess early radiation enteropathy...

BACKGROUND: Intestinal fibrosis is a late complication of pelvic radiotherapy. Epithelial-to-mesenchymal transition (EMT) plays an important role in tissue fibrosis. The aim of this study was to examine the effect of soluble dietary fiber on radiation-induced intestinal EMT and fibrosis in a mouse model. MATERIALS AND METHODS: Apple pectin (4% wt/wt in drinking water) was administered to wild-type and pVillin-Cre-EGFP transgenic mice with intestinal fibrosis induced by a single dose of abdominal irradiation of 10 Gy...

The gastrointestinal tract is responsible for a multitude of digestive and immune functions which depend upon the balanced interaction of the intestinal microbiota, diet, gut barrier function, and mucosal immune response. Disruptions in one or more of these factors can lead to intestinal disorders or enteropathies which are characterized by intestinal inflammation, increased gut permeability, and reduced capacity to absorb nutrients. Enteropathy is frequently associated with human immunodeficiency virus (HIV) infection, inflammatory bowel disease, autoimmune enteropathy, radiation enteritis, and irritable bowel syndrome (IBS), where pathologic changes in the intestinal tract lead to abdominal discomfort, bloating, abnormal bowel function (e...

New gastrointestinal symptoms are frequent after pelvic radiotherapy and can greatly affect the quality of life of cancer survivors. The effect of radiation on the intestinal microbiota, and the clinical implications of a modified microbial balance after radiotherapy are now beginning to emerge. In this Personal View, we show the importance of the microbiota for intestinal homoeostasis, and discuss the similarity between inflammatory bowel disease, which has been extensively researched, and radiation-induced gastrointestinal toxicity...

Human intestinal microbiota create a complex polymicrobial ecology. This is characterised by its high population density, wide diversity and complexity of interaction. Any dysbalance of this complex intestinal microbiome, both qualitative and quantitative, might have serious health consequence for a macro-organism, including small intestinal bacterial overgrowth syndrome (SIBO). SIBO is defined as an increase in the number and/or alteration in the type of bacteria in the upper gastrointestinal tract. There are several endogenous defence mechanisms for preventing bacterial overgrowth: gastric acid secretion, intestinal motility, intact ileo-caecal valve, immunoglobulins within intestinal secretion and bacteriostatic properties of pancreatic and biliary secretion...

PURPOSE OF REVIEW: Injury to the small bowel from ionizing radiation occurs commonly in patients undergoing cancer therapy and less commonly in instances of accidental radiation overexposure. Several lines of evidence now suggest that dynamic interactions between the host's enteric microbiota and innate immune system are important in modulating the intestinal response to radiation. Here, we will review recent developments in the area of acute radiation enteropathy and examine the current state of knowledge regarding the impact of host-microbial interactions in the process...