Faecal microbiota transplantation protects against radiation-induced toxicity

Microbiota transplantation: concept, methodology and strategy for its modernization

Fecal microbiota transplantation (FMT) has become a research focus of biomedicine and clinical medicine in recent years. The clinical response from FMT for different diseases provided evidence for microbiota-host interactions associated with various disorders, including Clostridium difficile infection, inflammatory bowel disease, diabetes mellitus, cancer, liver cirrhosis, gut-brain disease and others. To discuss the experiences of using microbes to treat human diseases from ancient China to current era should be important in moving standardized FMT forward and achieving a better future. Here, we review the changing concept of microbiota transplantation from FMT to selective microbiota transplantation, methodology development of FMT and step-up FMT strategy based on literature and state experts' perspectives.

The importance of the vascular endothelial barrier in the immune-inflammatory response induced by radiotherapy

Altered by ionising radiation, the vascular network is considered as a prime target to limit normal tissue damage and improve tumour control in radiotherapy (RT). Irradiation damages and/or activates endothelial cells, which then participate in the recruitment of circulating cells, especially by overexpressing cell adhesion molecules, but also by other as yet unknown mechanisms. Radiation-induced lesions are associated with infiltration of immune-inflammatory cells from the blood and/or the lymph circulation. Damaged cells from the tissues and immune-inflammatory resident cells release factors that attract cells from the circulation, leading to the restoration of tissue balance by fighting against infection, elimination of damaged cells and healing of the injured area. In normal tissues that surround the tumours, the development of an immune-inflammatory reaction in response to radiation-induced tissue injury can turn out to be chronic and deleterious for the organ concerned, potentially leading to fibrosis and/or necrosis of the irradiated area. Similarly, tumours can elicit an immune-inflammation reaction, which can be initialised and amplified by cancer therapy such as radiotherapy, although immune checkpoints often allow many cancers to be protected by inhibiting the T-cell signal. Herein, we have explored the involvement of vascular endothelium in the fate of healthy tissues and tumours undergoing radiotherapy. This review also covers current investigations that take advantage of the radiation-induced response of the vasculature to spare healthy tissue and/or target tumours better.

Gut microbiota modulates alcohol withdrawal-induced anxiety in mice

Excessive alcohol consumption remains a major public health problem that affects millions of people worldwide. Accumulative experimental evidence has suggested an important involvement of gut microbiota in the modulation of host's immunological and neurological functions. However, it is previously unknown whether enteric microbiota is implicated in the formation of alcohol withdrawal-induced anxiety. Using a murine model of chronic alcoholism and withdrawal, we examined the impact of alcohol consumption on the possible alterations of gut microbiota as well as alcohol withdrawal-induced anxiety and behavior changes. The 16S rRNA sequencing revealed that alcohol consumption did not alter the abundance of bacteria, but markedly changed the composition of gut microbiota. Moreover, the transplantation of enteric microbes from alcohol-fed mice to normal healthy controls remarkably shaped the composition of gut bacteria, and elicited behavioral signs of alcohol withdrawal-induced anxiety. Using quantitative real-time polymerase chain reaction, we further confirmed that the expression of genes implicated in alcohol addiction, BDNF, CRHR1 and OPRM1, was also altered by transplantation of gut microbes from alcohol-exposed donors. Collectively, our findings suggested a possibility that the alterations of gut microbiota composition might contribute to the development of alcohol withdrawal-induced anxiety, and reveal potentially new etiologies for treating alcohol addiction.

Hydrogen-water ameliorates radiation-induced gastrointestinal toxicity via MyD88's effects on the gut microbiota

Although radiation therapy is a cornerstone of modern management of malignancies, various side effects are inevitably linked to abdominal and pelvic cancer after radiotherapy. Radiation-mediated gastrointestinal (GI) toxicity impairs the life quality of cancer survivors and even shortens their lifespan. Hydrogen has been shown to protect against tissue injuries caused by oxidative stress and excessive inflammation, but its effect on radiation-induced intestinal injury was previously unknown. In the present study, we found that oral gavage with hydrogen-water increased the survival rate and body weight of mice exposed to total abdominal irradiation (TAI); oral gavage with hydrogen-water was also associated with an improvement in GI tract function and the epithelial integrity of the small intestine. Mechanistically, microarray analysis revealed that hydrogen-water administration upregulated miR-1968-5p levels, thus resulting in parallel downregulation of MyD88 expression in the small intestine after TAI exposure. Additionally, high-throughput sequencing showed that hydrogen-water oral gavage resulted in retention of the TAI-shifted intestinal bacterial composition in mice. Collectively, our findings suggested that hydrogen-water might be used as a potential therapeutic to alleviate intestinal injury induced by radiotherapy for abdominal and pelvic cancer in preclinical settings.

Seminal bacterial composition in patients with obstructive and non-obstructive azoospermia

A number of culture-dependent and -independent studies have reported that the number and significance of bacterial species in semen may have been underestimated. The aim of the present study was to profile the seminal microbiome in patients with obstructive or non-obstructive azoospermia. A high-throughput sequencing method was adopted to sequence genomic DNA extracted from the semen of healthy people (C group), patients with obstructive azoospermia (OA group) and patients with non-obstructive azoospermia (NOA group). The results revealed that Firmicutes, Proteobacteria, Bacteroidetes and Actinobacteria species comprised the majority of bacteria in the C (98.14%), OA (98.26%) and NOA (90.96%) groups. Patients in the OA and NOA groups exhibited an increase in Bacteroidetes and Firmicutes, whereas the number of Proteobacteria and Actinobacteria were decreased compared with the C group. A total of 398 common operational taxonomic units were identified, of which 27 belonged to the genus Lactobacillus. Furthermore, Phylogenetic Investigation of Communities by Reconstruction of Unobserved States analysis indicated that the pathogenic species and reduced biodiversity in the semen of patients with azoospermia may result in an increased risk of metabolic, infectious and immune diseases. In the present study, the seminal microbiome of patients with obstructive or non-obstructive azoospermia was explored, which may be useful for developing novel treatments against azoospermia as well as for its diagnosis.

Faecal microbiota transplantation protects against radiation-induced toxicity

Severe radiation exposure may cause acute radiation syndrome, a possibly fatal condition requiring effective therapy. Gut microbiota can be manipulated to fight against many diseases. We explored whether intestinal microbe transplantation could alleviate radiation‐induced toxicity. High‐throughput sequencing showed that gastrointestinal bacterial community composition differed between male and female mice and was associated with susceptibility to radiation toxicity. Faecal microbiota transplantation (FMT) increased the survival rate of irradiated animals, elevated peripheral white blood cell counts and improved gastrointestinal tract function and intestinal epithelial integrity in irradiated male and female mice. FMT preserved the intestinal bacterial composition and retained mRNA and long non‐coding RNA expression profiles of host small intestines in a sex‐specific fashion. Despite promoting angiogenesis, sex‐matched FMT did not accelerate the proliferation of cancer cells in vivo. FMT might serve as a therapeutic to mitigate radiation‐induced toxicity and improve the prognosis of tumour patients after radiotherapy.

Fecal Microbiota Transplantation: Beyond Clostridium difficile

PURPOSE OF REVIEW

Fecal microbiota transplantation (FMT) has been established as standard of care in the treatment of antibiotic refractory Clostridium difficile infection (RCDI). This review examines the current evidence that exists to support the use of FMT in the treatment of human disease beyond C. difficile infection.

RECENT FINDINGS

Beneficial effects of FMT have been described in case series or small prospective trials on a wide spectrum of conditions, including inflammatory bowel disease, functional gastrointestinal disorders, non-alcoholic steatohepatitis, alcoholic hepatitis, hepatic encephalopathy, and neuropsychiatric conditions, and in limiting antibiotic-resistant bacterial infections. Each of these proposed indications for FMT is associated with an underlying dysbiosis of the gastrointestinal microbiota and generally a clinical response is linked with a restoration of the gut microbiota. The potential of fecal microbial transplantation to alter disease course shows promise but further large-scale studies are necessary to understand limitations as well as how best to utilize this therapy.

Total abdominal irradiation exposure impairs cognitive function involving miR-34a-5p/BDNF axis

Radiotherapy is often employed to treat abdominal and pelvic malignancies, but is frequently accompanied by diverse acute and chronic local injuries. It was previously unknown whether abdominal and pelvic radiotherapy impairs distant cognitive dysfunction. In the present study, we demonstrated that total abdominal irradiation (TAI) exposure caused cognitive deficits in mouse models. Mechanically, microarray assay analysis revealed that TAI elevated the expression level of miR-34a-5p in small intestine tissues and peripheral blood (PD), which targeted the 3'UTR of Brain-derived neurotrophic factor (Bdnf) mRNA in hippocampus to mediate cognitive dysfunction. Tail intravenous injection of miR-34a-5p antagomir immediately after TAI exposure rescued TAI-mediated cognitive impairment via blocking the up-regulation of miR-34a-5p in PD, resulting in restoring the Bdnf expression in the hippocampus. More importantly, high throughput sequencing validated that the gut bacterial composition of mice was shifted after TAI exposure, which was retained by miR-34a-5p antagomir injection. Thus, our findings provide new insights into pathogenic mechanism underlying abdominal and pelvic radiotherapy-mediated distant cognitive impairment.