Oral Curcumin-Thioketal-Inulin Conjugate Micelles against Radiation-Induced Enteritis

Radiation-induced enteritis is an unavoidable complication associated with pelvic tumor radiotherapy, significantly influencing the prognosis of cancer patients. The limited availability of commercial gastrointestinal radioprotectors in clinical settings poses a substantial challenge in preventing radiation enteritis. Despite the inherent radioprotective characteristics of Cur in vitro, its poor solubility in water, instability, and low bioavailability lead to inferior therapeutic effects in vivo. Herein, we developed novel ROS-responsive micelles (CTI) from inulin and curcumin, aimed at mitigating radiation enteritis. CTI micelles had excellent solubility and stability. Importantly, CTI improved the cytotoxicity and bioavailability of curcumin, thereby showing enhanced effectiveness in neutralizing ROS induced by radiation, safeguarding against DNA damage, and reducing radiation-induced cellular mortality. Moreover, in a radiation enteritis mice model, CTI not only alleviated severe radiation-induced intestinal injury but also improved redox-related indicators and reduced inflammatory cytokine expression. Furthermore, CTI effectively increased gut microbiota abundance and maintained gut homeostasis. In conclusion, CTI could be a promising candidate for the clinical management of radiation enteritis. Our study provides a new perspective for radioprotection using natural antioxidants.

Significant correlation between glucose metabolism status and acute radiation enteritis resulting from concurrent chemoradiotherapy in rectal cancer

OBJECTIVE

To explore the relationship between glucose metabolism and acute radiation enteritis from chemoradiotherapy for rectal cancer.

METHODS

In this retrospective study, the clinical data of 75 rectal cancer patients who received concurrent chemoradiotherapy in Binzhou Second People's Hospital from February 2019 to February 2022 were collected and analyzed. According to the Radiation Therapy Oncology Group (RTOG)/European Organization for Research on Treatment of Cancer (EORTC) radiation response grading criteria, the patients were classified into four groups with different glucose metabolism statuses: NGR (normal glucose regulation) group, IFG (impaired fasting glucose) group, IGT (impaired glucose tolerance) group, and DM (diabetes mellitus) group. Two-factor logistic regression was used to analyze whether IFG, IGT, or DM were risk factors for acute radiation enteritis.

RESULTS

(1) The fasting plasma glucose (FPG, F=20.550, P < 0.001), 2-hour post-meal blood glucose (2hPG, F=14.920, P < 0.001), triglycerides (TG, F=3.355, P=0.024), high-density lipoprotein cholesterol (HDL-C) (F=4.109, P=0.010), low-density lipoprotein cholesterol (LDL-C, F=4.545, P=0.006), and systolic blood pressure (SBP, F=5.398, P=0.002) differed greatly among the NGR group, IFG group, IGT group, and DM group, all P < 0.05. (2) The incidence of acute radiation enteritis was 34.67% in the 75 patients, and in DM patients it was higher than in the NGR, IFG, or IGT patients (χ²=14.702, P=0.002). (3) There were significant differences in BMI (F=3.594, P=0.044) and DBP (F=3.954, P=0.033) among the asymptomatic group, mild group, and severe group (P < 0.05). (4) Body mass index (BMI) was positively correlated with acute radiation enteritis in IFG, IGT, and DM patients (OR=1.361, P=0.020). (5) DM was positively correlated with acute radiation enteritis (OR=6.167, P=0.039).

CONCLUSIONS

DM was significantly correlated with acute radiation enteritis induced by concurrent chemoradiotherapy for rectal cancer, while IFG and IGT were not.

Free heme exacerbates colonic injury induced by anti-cancer therapy

Gastrointestinal inflammation and bleeding are commonly induced by cancer radiotherapy and chemotherapy but mechanisms are unclear. We demonstrated an increased number of infiltrating heme oxygenase-1 positive (HO-1+) macrophages (Mø, CD68+) and the levels of hemopexin (Hx) in human colonic biopsies from patients treated with radiation or chemoradiation versus non-irradiated controls or in the ischemic intestine compared to matched normal tissues. The presence of rectal bleeding in these patients was also correlated with higher HO-1+ cell infiltration. To functionally assess the role of free heme released in the gut, we employed myeloid-specific HO-1 knockout (LysM-Cre : Hmox1flfl), hemopexin knockout (Hx-/-) and control mice. Using LysM-Cre : Hmox1flfl conditional knockout (KO) mice, we showed that a deficiency of HO-1 in myeloid cells led to high levels of DNA damage and proliferation in colonic epithelial cells in response to phenylhydrazine (PHZ)-induced hemolysis. We found higher levels of free heme in plasma, epithelial DNA damage, inflammation, and low epithelial cell proliferation in Hx-/- mice after PHZ treatment compared to wild-type mice. Colonic damage was partially attenuated by recombinant Hx administration. Deficiency in Hx or Hmox1 did not alter the response to doxorubicin. Interestingly, the lack of Hx augmented abdominal radiation-mediated hemolysis and DNA damage in the colon. Mechanistically, we found an altered growth of human colonic epithelial cells (HCoEpiC) treated with heme, corresponding to an increase in Hmox1 mRNA levels and heme:G-quadruplex complexes-regulated genes such as c-MYC, CCNF, and HDAC6. Heme-treated HCoEpiC cells exhibited growth advantage in the absence or presence of doxorubicin, in contrast to poor survival of heme-stimulated RAW247.6 Mø. In summary, our data indicate that accumulation of heme in the colon following hemolysis and/or exposure to genotoxic stress amplifies DNA damage, abnormal proliferation of epithelial cells, and inflammation as a potential etiology for gastrointestinal syndrome (GIS).

[Molecular mechanism of ginsenoside Rg_1 against radiation enteritis: based on network pharmacology and in vitro experiment]

Via network pharmacology, molecular docking, and cellular experiment, this study explored and validated the potential molecular mechanism of ginsenoside Rg_1(Rg_1) against radiation enteritis. Targets of Rg_1 and radiation enteritis were retrieved from BATMAN-TCM, SwissTargetPrediction, and GeneCards. Cytoscape 3.7.2 and STRING were employed for the construction of protein-protein interaction(PPI) network for the common targets, and screening of core targets. DAVID was used for Gene Ontology(GO) term and Kyoto Encyclopedia of Genes and Genomes(KEGG) pathway enrichment to predict the possible mechanism, followed by molecular docking of Rg_1 with core targets and cellular experiment. For the cellular experiment, ~(60)Co-γ irradiation was performed for mo-deling of IEC-6 cells, which were then treated with Rg_1, protein kinase B(AKT) inhibitor LY294002, and other drugs to verify the effect and mechanism of Rg_1. The results showed that 29 potential targets of Rg_1, 4 941 disease targets, and 25 common targets were screened out. According to the PPI network, the core targets were AKT1, vascular endothelial growth factor A(VEGFA), heat shock protein 90 alpha family class A member 1(HSP90AA1), Bcl-2-like protein 1(BCL2L1), estrogen receptor 1(ESR1), etc. The common targets were mainly involved in the GO terms such as positive regulation of RNA polymerase Ⅱ promoter transcription, signal transduction, positive regulation of cell proliferation, and other biological processes. The top 10 KEGG pathways included phosphoinositide 3-kinase(PI3K)/AKT pathway, RAS pathway, mitogen-activated protein kinase(MAPK) pathway, Ras-proximate-1(RAP1) pathway, and calcium pathway, etc. Molecular docking showed that Rg_1 had high binding affinity to AKT1, VEGFA, HSP90AA1, and other core targets. Cellular experiment indicated that Rg_1 can effectively improve cell viability and survival, decrease apoptosis after irradiation, promote the expression of AKT1 and B-cell lymphoma-extra large(BCL-XL), and inhibit the expression of the pro-apoptotic protein Bcl-2-associated X protein(BAX). In conclusion, through network pharmacology, molecular docking, and cellular experiment, this study verified the ability of Rg_1 to reduce radiation enteritis injury. The mechanism was that it regulated PI3K/AKT pathway, thereby suppressing apoptosis.

Potential applications of drug delivery technologies against radiation enteritis

INTRODUCTION

The incidence of abdominal tumors, such as colorectal and prostate cancers, continually increases. Radiation therapy is widely applied in the clinical treatment of patients with abdominal/pelvic cancers, but it often unfortunately causes radiation enteritis (RE) involving the intestine, colon, and rectum. However, there is a lack of suitable treatment options for effective prevention and treatment of RE.

AREAS COVERED

Conventional clinical drugs for preventing and treating RE are usually applied by enemas and oral administration. Innovative gut-targeted drug delivery systems including hydrogels, microspheres, and nanoparticles are proposed to improve the prevention and curation of RE.

EXPERT OPINION

The prevention and treatment of RE have not attracted sufficient attention in the clinical practice, especially compared to the treatment of tumors, although RE takes patients great pains. Drug delivery to the pathological sites of RE is a huge challenge. The short retention and weak targeting of conventional drug delivery systems affect the therapeutic efficiency of anti-RE drugs. Novel drug delivery systems including hydrogels, microspheres, and nanoparticles can allow drugs long-term retention in the gut and targeting the inflammation sites to alleviate radiation-induced injury.

CXCL16 inhibits epithelial regeneration and promotes fibrosis during the progression of radiation enteritis

Radiation enteritis (RE) is a prevalent complication of radiotherapy for pelvic malignant tumors, characterized by severe intestinal epithelial destruction and progressive submucosal fibrosis. However, little is known about the pathogenesis of this disease, and so far, there is no specific targeted therapy. Here, we report that CXCL16 is upregulated in the injured intestinal tissues of RE patients and in a mouse model. Genetic deletion of Cxcl16 mitigates fibrosis and promotes intestinal stem cell-mediated epithelial regeneration after radiation injury in mice. Mechanistically, CXCL16 functions on myofibroblasts through its receptor CXCR6 and activates JAK3/STAT3 signaling to promote fibrosis and, at the same time, to transcriptionally modulate the levels of BMP4 and hepatocyte growth factor (HGF) in myofibroblasts. Moreover, we find that CXCL16 and CXCR6 auto- and cross-regulate themselves in positive feedback loops. Treatment with CXCL16 neutralizing monoclonal antibody attenuates fibrosis and improves the epithelial repair in RE mouse model. Our findings emphasize the important role of CXCL16 in the progression of RE and suggest that CXCL16 signaling could be a potential therapeutic target for RE. © 2022 The Pathological Society of Great Britain and Ireland.

Global trends of researches on radioactive enteritis: A bibliometric and visualization study

BACKGROUND

Radiation enteritis (RE) caused by radiation therapy, can seriously affect human health. Recently, studies on RE have been growing rapidly, but there are no bibliometric studies on RE. This study aims to explore the development trends and research hotspots of RE.

METHODS

Academic papers on the Web of Science were retrieved on the topic of "radioactive enteritis" from the establishment of the database to December 2020. Countries, institutions, and subjects selected in this field were visualized using Citespace, HistCite, and Vosviewer. The annual trends in publications, distribution, co-authorship status, and research hotspots were analyzed.

RESULTS

The authors ranked first in terms of publication amount were Delaney, Francois, Milliat, and Vozenin-Brotons. The United States had the highest number of posts, followed by China, France, the United Kingdom, and Spain.

CONCLUSION

Future research in the field of RE will focus on double-blind clinical trials of RE, and the related mechanisms, such as oxidative stress and apoptosis.

Treatment of Radiation Enteritis With Fecal Transplantation

Radiation enteritis (RE) is a frequent complication in patients who undergo pelvic irradiation, and this condition has been increasingly diagnosed. Fecal microbiota transplantation (FMT) is being developed in recent years, and it has remarkable curative effect for the clostridium and inflammatory bowel disease. Herein, we present a case of recurrent RE in a 59-year-old woman with RE 18 years after radiotherapy for cervical carcinoma. Fecal microbiota transplantation therapy with intestinal flora from her 18-year-old son was applied and was successful in relieving the symptoms. To the best of our knowledge, this study is the first case report of FMT in a patient with RE.

Study on the protective effect and mechanism of Liriodendrin on radiation enteritis in mice

Patients receiving pelvic or abdominal radiotherapy may experience acute and/or chronic side effects due to gastrointestinal changes. However, effective medicine for treating radiation enteritis has not been found yet. Sargentodoxa cuneata is a famous Chinese medicine used to treat intestinal inflammation, and our research team has found the main biologically active compound through its extraction, which is Liriodendrin. In this study, we found that Liriodendrin can reduce the expression of Cer, Cer1P and S1P in the sphingolipid pathway, thereby reducing the histological damage to the intestinal tract of mice and inhibiting the apoptosis of intestinal tissue cells. In addition, Liriodendrin can reduce the levels of pro-inflammatory cytokines (IL-6 and TNF-α), and it is suggested through flow cytometry that the proportion of neutrophils in the intestinal tissue can decrease due to the existence of Liriodendrin. At the same time, the western blot evaluation revealed that Liriodendrin significantly inhibited the activation of Bcl-2/Bax/Caspase-3 and NF-κB signaling pathways. The results show that Liriodendrin can inhibit intestinal inflammation and intestinal cell apoptosis through the sphingolipid pathway. Therefore, the aforementioned results demonstrated that Liriodendrin may be a promising drug for the treatment of radiation enteritis.

MST1/2 inhibitor XMU-MP-1 alleviates the injury induced by ionizing radiation in haematopoietic and intestinal system

The Hippo signalling pathway has been considered as potential therapeutic target in self‐renewal and differentiation of stem and progenitor cells. Thus, mammalian Ste20‐like kinase 1/2 (MST1/2) as the core serine‐threonine kinases in the Hippo signalling pathway has been investigated for its role in immunological disease. However, little information of MST1/2 function in bone marrow suppression induced by ionizing radiation was fully investigated. Here, we reported that MST1/2 inhibitor XMU‐MP‐1 could rescue the impaired haematopoietic stem cells (HSCs) and progenitor cells (HPCs) function under oxidative stress condition. Also, XMU‐MP‐1 pretreatment markedly alleviated the small intestinal system injury caused by the total body irradiation 9 Gy and extended the average survival days of the mice exposed to the lethal dose radiation. Therefore, irradiation exposure causes the serious pathological changes of haematopoietic and intestinal system, and XMU‐MP‐1 could prevent the ROS production, the haematopoietic cells impairment and the intestinal injury. These detrimental effects may be associated with regulating NOX/ROS/P38MARK pathway by MST1/2.

Gut metabolite Urolithin A mitigates ionizing radiation-induced intestinal damage

Ionizing radiation (IR)‐induced intestinal damage is the major and common injury of patients receiving radiotherapy. Urolithin A (UroA) is a metabolite of the intestinal flora of ellagitannin, a compound found in fruits and nuts such as pomegranates, strawberries and walnuts. UroA shows the immunomodulatory and anti‐inflammatory capacity in various metabolic diseases. To evaluate the radioprotective effects, UroA(0.4, 2 and 10 mg/kg) were intraperitoneally injected to C57BL/6 male mice 48, 24, 1 h prior to and 24 h after 9.0Gy TBI. The results showed that UroA markedly upregulated the survival of irradiated mice, especially at concentration of 2 mg/kg. UroA improved the intestine morphology architecture and the regeneration ability of enterocytes in irradiated mice. Then, UroA significantly decreased the apoptosis of enterocytes induced by radiation. Additionally, 16S rRNA sequencing analysis showed the effect of UroA is associated with the recovery of the IR‐induced intestinal microbacteria profile changes in mice. Therefore, our results determinated UroA could be developed as a potential candidate for radiomitigators in radiotherapy and accidental nuclear exposure. And the beneficial functions of UroA might be associated with the inhibition of p53‐mediated apoptosis and remodelling of the gut microbes.

The Impact of Gut Microbiota on Radiation-Induced Enteritis

Radiotherapy is an important treatment for abdominal tumors. A critical side effect for this therapy is enteritis. In this review, we aim to summarize recent findings in radiation enteritis, in particular the role of gut microbiota dysbiosis in the development and therapy of the disease. Gut microbiota dysbiosis plays an important role in the occurrence of various diseases, such as radiation enteritis. Abdominal radiation results in changes in the composition of microbiota and reduces its diversity, which is mainly reflected in the decrease of Lactobacillus spp. and Bifidobacterium spp. and increase of Escherichia coli and Staphylococcus spp. Gut microbiota dysbiosis aggravates radiation enteritis, weakens intestinal epithelial barrier function, and promotes inflammatory factor expression. Pathogenic Escherichia coli induce the rearrangement and redistribution of claudin-1, occludin, and ZO-1 in tight junctions, a critical component in intestinal epithelial barrier. In view of the role that microbiome plays in radiation enteritis, we believe that intestinal flora could be a potential biomarker for the disease. Correction of microbiome by application of probiotics, fecal microbiota transplantation (FMT), and antibiotics could be an effective method for the prevention and treatment of radiation-induced enteritis.

Randomised clinical trial of a gastrointestinal care bundle to reduce symptoms in patients with pelvic cancer undergoing chemoradiotherapy

OBJECTIVE

Pelvic radiotherapy is used to treat 17 000 people in the UK each year. Eight in 10 develop difficult bowel problems during pelvic treatment, especially diarrhoea, urgency and incontinence. Some cannot complete treatment, reducing the chance of cancer cure. Undertaking gastroenterologist-led investigation and management during pelvic radiotherapy has never been evaluated. In this study, we aimed to assess whether patients could successfully receive a novel gastrointestinal (GI) care bundle during chemoradiotherapy (feasibility aim) and would experience reduced symptom severity (clinical impact aim).

DESIGN

This randomised controlled trial recruited patients with cervical and bladder cancers undergoing radical chemoradiotherapy. Participants were randomised to intervention or control groups. Questionnaire and anthropometric data were collected. All intervention group patients received individualised dietary counselling weekly throughout treatment, and if bowel symptoms developed they were offered rapid-access investigation and treatment for any identified pathology: lactose intolerance, bacterial overgrowth or bile acid malabsorption.

RESULTS

Feasibility: 50 participants were recruited, 24 were randomised to the intervention group and 26 to the control group. All completed 20 fractions of external beam pelvic radiotherapy. It was possible to perform 57/72 (79%) of proposed intervention tests with no disruption of oncological management.

CLINICAL IMPACT

All participants developed GI symptoms during radiotherapy. The median symptom score for each group increased from baseline at 6 weeks. This was from 0.156 (0.000-0.333) to 0.600 (0.250-1.286) in the control group, and from 0.00 (0.000-0.300) to 0.402 (0.000-0.667) in the intervention group.

CONCLUSION

It was feasible to recruit to and deliver a randomised controlled trial of interventions in patients undergoing pelvic chemoradiotherapy. Lower median bowel scores were reported in the intervention group at 6 weeks, with fewer patients experiencing symptoms overall.

TRIAL REGISTRATION NUMBER

ISRCTN783488.

External treatment of traditional Chinese medicine for radiation enteritis: A protocol for systematic review and meta-analysis

BACKGROUND

Radiation enteritis (RE) is a common complication that often occurs after radiotherapy for abdominal and pelvic malignancies. RE could influence patients' quality of life seriously and it is difficult to cure by conventional treatments. A lot of studies have revealed that the external treatment of traditional Chinese medicine (TCM) for RE is a safe and economical approach, but there is no relevant systematic review. The present study performed a systematic review and meta-analysis to compare TCM external treatment and conventional treatment for RE to evaluate the effectiveness and safety of external treatment of traditional Chinese medicine in the treatment of RE.

METHODS

Cochrane Library, PubMed, Embase, China National Knowledge Infrastructure (CNKI), Wan-Fang database, VIP Chinese Science and Technique Journals Database, and the Chinese Biomedical Literature Database (CBM) were searched. The time of publication was limited from inception to April, 2021. Two reviewers independently searched for the selected articles and extract the data. The RevMan V.5.3 statistical software (Cochrane Collaboration) and Stata V.16.0 software were used to conduct the meta-analysis.

RESULTS

We will show the results of this study in a peer-reviewed journal.

CONCLUSION

This meta-analysis will provide reliable evidence for external treatment of TCM in the treatment of RE.

INPLASY REGISTRATION NUMBER

INPLASY202140120.

Ligustilide Prevents Radiation Enteritis by Targeting Gch1/BH4/eNOS to Improve Intestinal Ischemia

There is a high incidence of radiation enteritis (RE) after abdominal radiotherapy. The occurrence of RE seriously affects the treatment and quality of life of patients; however, its pathogenesis is complex and there are no effective drugs for its prevention or treatment. Intestinal ischemia plays an important role in the occurrence of enteritis. Previous studies have shown that targeting GTP-cyclohydrolase 1 (Gch1) to improve intestinal ischemia could be a new strategy to prevent and treat RE. A high content of the naturally occurring phthalide derivative ligustilide (LIG) has been found in the plant drug Rhizoma Ligustici Chuanxiong for the treatment of cardiovascular diseases. The purpose of this study was to evaluate the protective effects of LIG on RE. Ionizing radiation (IR) rat and endothelial cell models were used to observe and record rat body weights and stool morphologies, measure intestinal blood perfusion by laser Doppler blood flow imaging, determine the diastolic functions of mesenteric arteries, detect the levels of Gch1/BH₄/eNOS pathway-related proteins and regulatory molecules in the mesenteric arteries and endothelial cells, and predict affinity by molecular docking technology. The results showed that LIG significantly improved the body weights, loose stools, intestinal villi lengths, intestinal perfusion and vasodilatory functions of IR rats. LIG also significantly improved Gch1 protein and BH₄ levels in the mesenteric arteries and endothelial cells after IR, increased the NO content, reduced superoxide accumulation, and improved p-eNOS (Ser1177) levels in endothelial cells. LIG has good affinity for Gch1, which significantly improves its activity. These results indicate that LIG is the preferred compound for the prevention and treatment of RE by improving intestinal ischemia through the Gch1/BH₄/eNOS pathway. This study provides a theoretical basis and new research ideas for the development of new drugs for RE.

Endoscopically delivered Purastat for the treatment of severe haemorrhagic radiation proctopathy: a service evaluation of a new endoscopic treatment for a challenging condition

BACKGROUND

A total of 30 000 people are treated with pelvic radiotherapy annually in the UK. Rectal bleeding is common following pelvic radiotherapy and one of the main causes is radiation proctopathy (RP). Six per cent develop severe bleeding from RP, leading to anaemia requiring iron +/- blood transfusion. There are very few safe, effective, evidence-based treatments. Purastat is a haemostatic agent licensed for gastrointestinal bleeding. It is a self-assembling peptide that forms a molecular mesh in contact with blood, thereby sealing blood vessels. There are numerous studies showing its efficacy and safety in various surgical/endoscopic settings. This service evaluation reports the first experience of the use of Purastat in RP.

METHODS

Consecutive patients attending pelvic radiation disease clinic with severe refractory RP were offered treatment with Purastat. This was defined as rectal bleeding into the pan±anaemia with no response to rectal sucralfate. Purastat was applied endoscopically at four weekly intervals up to three times, with more as required. Bleeding severity, endoscopic grade and haemoglobin were recorded.

RESULTS

Twenty-one patients were treated (18 men, median age 76 years) with a median of three treatments. Ten were on antithrombotics, 1 had thrombocytopenia and 13 had anaemia at baseline. Median episodes of bleeding reduced from 4.5 (0-27) to 2 (0-16) in the 7 days prior to the first and third treatment, respectively. Endoscopic grade was improved. Mean haemoglobin increased from 116.0 to 122.7. There were no complications.

CONCLUSION

Even in this cohort of severe refractory RP, there was an improvement in bleeding and endoscopic grade with Purastat. A randomised controlled trial is planned.

Alterations of the Gut Microbiome Composition and Lipid Metabolic Profile in Radiation Enteritis

Radiation enteritis (RE) is a common complication in cancer patients receiving radiotherapy. Although studies have shown the changes of this disease at clinical, pathological and other levels, the dynamic characteristics of local microbiome and metabolomics are hitherto unknown. We aimed to examine the multi-omics features of the gut microecosystem, determining the functional correlation between microbiome and lipid metabolites during RE activity. By delivering single high-dose irradiation, a RE mouse model was established. High-throughput 16S rDNA sequencing and global lipidomics analysis were performed to examine microbial and lipidomic profile changes in the gut microecosystem. Spearman correlation analysis was used to determine the functional correlation between bacteria and metabolites. Clinical samples were collected to validate the above observations. During RE activity, the intestinal inflammation of the mice was confirmed by typical signs, symptoms, imaging findings and pathological evidences. 16S datasets revealed that localized irradiation dramatically altered the gut microbial composition, resulting in a decrease ratio of Bacteroidetes to Firmicutes. Lipidomics analysis indicated the remarkable lipidomic profile changes in enteric epithelial barrier, determining that glycerophospholipids metabolism was correlated to RE progression with the highest relevance. Spearman correlation analysis identified that five bacteria-metabolite pairs showed the most significant functional correlation in RE, including Alistipes-PC(36:0e), Bacteroides-DG(18:0/20:4), Dubosiella-PC(35:2), Eggerthellaceae-PC(35:6), and Escherichia-Shigella-TG(18:2/18:2/20:4). These observations were partly confirmed in human specimens. Our study provided a comprehensive description of microbiota dysbiosis and lipid metabolic disorders in RE, suggesting strategies to change local microecosystem to relieve radiation injury and maintain homeostasis.

Multi-slice spiral CT evaluation of chronic radiation colitis and rectitis

The aim of the present study was to retrospectively analyse the multi-slice spiral CT (MSCT) findings of radiation colitis and rectitis (RC&R). A total of 23 cases of RC&R detected by helical CT were included. The CT findings and clinical and endoscopy data of the patients were reviewed. The primary tumours included cancers of the cervix (n=17), rectum (n=4), ovaries (n=1) and bladder (n=1). The total dose of radiation per patient was 46-60 Gy (mean, 49.7 Gy) delivered over 5 weeks. The CT manifestations included different degrees of increased thickness of the intestinal wall (n=20, 87.0%), with a maximum thickness of 16.6 mm. On enhanced CT, the target sign was observed (n=16, 69.9%), with an obviously enhanced mucosa and/or serosa and the following changes observed: Oedema and increased density of the mesentery (n=15, 65.2%); increased density of the subcutaneous fat, and blurred and oedematous pelvic wall muscles (n=4, 17.4%), with the obturator internus and levator ani muscles being most commonly affected; narrowed intestinal lumen (n=3, 13.0%); and a small amount of ascitic fluid (n=2, 8.7%) located in the paracolic sulci and bladder or Douglas pouch. The 23 patients underwent colonoscopy and were diagnosed with RC&R. The major manifestations included telangiectasia and mucosal hyperaemia (n=21, 91.3%). MSCT of chronic RC&R (CRC&R) was associated with certain characteristic findings, which, combined with a medical history of radiotherapy and the clinical manifestations, may prove to be of value in the diagnosis of CRC&R.

Gastrointestinal consequences of cancer treatment: evaluation of 10 years' experience at a tertiary UK centre

OBJECTIVE

Up to 90% of patients treated for pelvic cancers experience chronic gastrointestinal (GI) symptoms. This study characterises this patient cohort at a single centre, addressing a paucity of publications reporting 'real-world' experiences.

METHOD

Outpatient referrals, from oncology to the gastroenterology and nutrition services, at a tertiary London hospital from 2006 to 2016, were retrospectively identified. Patient characteristics, reported symptoms, investigations, diagnoses, response to therapeutics and follow-up were recorded.

RESULTS

Of 269 patients referred, 81% were within the latter 5 years. A total of 260 patients had diagnoses of pelvic cancers (prostatic (52%), cervical (19%) and endometrial (19%)). Among 247 treated with radiotherapy, the median time from radiotherapy to symptom onset was 8 months. Common symptoms were rectal bleeding (51%), diarrhoea (32%), faecal urgency (19%) and pain (19%). Patients underwent a median of three investigations including lower GI endoscopy (86%), thyroid function tests (33%) and glucose hydrogen breath test (30%). Diagnoses included radiation proctopathy (39%), colonic polyps (16%), pelvic floor dysfunction (12%), bile acid malabsorption (BAM) (8%), small intestinal bacterial overgrowth (SIBO) (8%), vitamin D deficiency (7%) and iron deficiency (7%). Among 164 discharged patients, the time to discharge was 7 months, after a median of two appointments.

CONCLUSIONS

This unique patient group reports a complex mix of symptoms and requires specialist review and consideration of often uninvestigated diagnoses (pelvic dysfunction, BAM, SIBO and nutritional deficiencies). Such patients are often overlooked, compared with those suffering many other chronic GI disorders. Further reports from non-dedicated centres treating patients with pelvic radiation disease will aid in understanding of secondary GI diagnoses and variation in practice.

[Radioactive Enteritis and Gut Microecology]

Radioactive enteritis(RE)is one of the most serious and common complications of intestinal tract caused by radiotherapy for malignant tumors in abdominal cavity,pelvic cavity,or retroperitoneum.Involved intestinal diseases are widespread,complex,and persistent,which make treatment difficult and ineffective.Short bowel syndrome can develop in some serious cases.Gut flora is the largest and most complex micro-ecosystem in human body and has a wide range of functions.Studies have shown that intestinal flora plays an important role in radiation-induced RE.This article summarizes recent research advances in the relationship between RE and gut flora.

Effect of Modified Xijiao Dihuang Decoction () on Intestinal Flora and Th17/Treg in Rats with Radiation Enteritis

OBJECTIVE

To observe the effect of Modified Xijiao Dihuang Decoction (, MXDD) on rats with radiation enteritis, and explore its action mechanism.

METHODS

Thirty female Sprague Dawley rats were divided into the control, model, dexamethasone (DXM), golden bifid (GB) and MXDD groups using random number table, 6 rats in each group. Except the control group, the other rats were developed into radiation enteritis model by exposing to a single ⁶⁰Co-γ ray at a dose of 11 Gy. The rats in the DXM, GB and MXDD groups were treated with DXM (1.425 mg/kg), GB (0.8 g/kg) and MXDD (36.0 g/kg) for 3 days, respectively. Body weight and diarrhea condition of rats were evaluated daily. On day 3, the feces of rats were collected for intestinal flora detection and the small intestinal tissues were also collected. Bacterial species annotation, alpha and beta diversities as well as composition of intestinal flora were detected and compared. The protein and mRNA expressions of interleukin 17 (IL-17), retinoid-related orphan nuclear receptor gamma t (ROR-γt) and forkhead/ winged helix transcription factor p3 (FoxP3) were determined by Western blot and polymerase chain reaction, respectively. The abundance and diversity of intestinal flora as well as the proportion at the phylum and genus levels were assayed by 16S rRNA metagenome sequencing. Correlation between intestinal flora and Th17/Treg was analyzed by heatmap method.

RESULTS

On day 1 to 3 after radiation, compared with the control group, the body weight in model group was decreased (P<0.05 or P<0.01). Compared with the model group, MXDD could alleviate weight loss and diarrhea caused by irradiation. At the phylum level, MXDD cause a significant increase in Firmicutes, and a decrease in Proteobacteria (P<0.05 or P<0.01). At the genus level, MXDD reduced the proportion of Escherichia Shigella (P<0.01). In addition, IL-17 and FoxP3 mRNA and protein expression levels were down-regulated and ROR-γt was up-regulated by MXDD treatment (P<0.05). Besides, Firmicutes and Lactobacillus were positively correlated with FoxP3 (r=0.73, 0.79, respectively; P<0.01), negatively correlated with IL-17 (r=0.66, 0.64, respectively; P<0.01 or P<0.05) and ROR-γt (r0.73, 0.81, respectively; P<0.01). Proteobacteria and Escherichia Shigella both had positive correlation with IL-17 (r 0.77, 0.57, respectively; P<0.01 or P<0.05 ) and ROR-γt (r=0.94, 0.79, respectively; P<0.01) and negative correlation with FoxP3 (r0.74, 0.65; P<0.01).

CONCLUSION

MXDD could improve the survival status of irradiated rats by regulating the richness, diversity and composition of intestinal flora, and restoring the balance of Th17/Treg.

Vitamin B12 Deficiency Anemia and Polyneuropathy Due to Chronic Radiation Enteritis

A 62-year-old Japanese woman developed numbness of the extremities and megaloblastic anemia. She had undergone total abdominal hysterectomy, whole-pelvis radiation therapy and chemotherapy for gynecological cancer 10 years before. Chronic abdominal pain, diarrhea and intermittent small-bowel obstruction had afflicted her for a long time. We diagnosed her with vitamin B12 deficiency anemia and polyneuropathy due to chronic radiation enteritis causing malabsorption. Vitamin B12 injections improved her numbness and anemia. The early diagnosis and treatment of deficiency of vitamin B12 are important. Physicians should regularly measure vitamin B12 levels and supplement vitamin B12 as needed in patients with chronic radiation enteritis.

Radiation-induced intestinal damage: latest molecular and clinical developments

Aim: To systematically review the prophylactic and therapeutic interventions for reducing the incidence or severity of intestinal symptoms among cancer patients receiving radiotherapy. Materials & methods: A literature search was conducted in the PubMed database using various search terms, including 'radiation enteritis', 'radiation enteropathy', 'radiation-induced intestinal disease', 'radiation-induced intestinal damage' and 'radiation mucositis'. The search was limited to in vivo studies, clinical trials and meta-analyses published in English with no limitation on publication date. Other relevant literature was identified based on the reference lists of selected studies. Results: The pathogenesis of acute and chronic radiation-induced intestinal damage as well as the prevention and treatment approaches were reviewed. Conclusion: There is inadequate evidence to strongly support the use of a particular strategy to reduce radiation-induced intestinal damage. More high-quality randomized controlled trials are required for interventions with limited evidence suggestive of potential benefits.

Empty pelvis syndrome: the use of breast prosthesis in the prevention of complications

AIM

Empty pelvis syndrome and radiation-induced bowel injury are two major clinical issues resulting from the pelvic dead space after pelvic exenteration (PE). In order to avoid these complications, different methods of pelvic floor reconstruction have been proposed. We report our experience on the use of breast prosthesis.

METHOD

Fifty-three patients who underwent PE and three who underwent palliative surgery with silicone breast prosthesis placement were included.

RESULTS

Forty-seven posterior PE, six total PE and three palliative procedures were identified. Sphincter preservation was feasible in 34 patients (62.3%). There were no deaths. Overall morbidity was 37.5%. There were no complications such as sepsis or obstruction related to the prosthesis. Adjuvant radiotherapy was delivered in 16 cases (30.1%) without any side-effects. Reconstruction of intestinal continuity was possible in 12 patients (36.3%) with sphincter preservation and the prosthesis allowed a prompt identification of the rectal stump.

CONCLUSION

Breast prosthesis placement is a simple and safe method to minimize complications resulting from empty pelvis syndrome and can be adopted to exclude bowel loops from the radiation field. Reconstruction of intestinal continuity after resection is also simplified.

Preclinical murine platform to evaluate therapeutic countermeasures against radiation-induced gastrointestinal syndrome

Currently, there are no therapies available to mitigate intestinal damage after radiation injury. Efforts to study and design new therapies are hampered by a lack of models that can be readily adopted to study therapeutic targets. Here we describe a preclinical platform to evaluate therapeutic countermeasures against intestinal radiation injury in vivo in a mouse model that permits inducible and reversible gene suppression following radiation exposure. We demonstrate that transient intestinal Apc suppression stimulates intestinal regeneration and mitigates lethality after radiation intestinal injury, thus validating pulsed Wnt pathway agonism as a therapeutic strategy. This platform can be readily adopted to study theoretically any gene of interest associated with the biology and treatment of intestinal radiation injury.

Radiation-induced gastrointestinal syndrome (RIGS) is a limiting factor for therapeutic abdominopelvic radiation and is predicted to be a major source of morbidity in the event of a nuclear accident or radiological terrorism. In this study, we developed an in vivo mouse-modeling platform that enables spatial and temporal manipulation of potential RIGS targets in mice following whole-abdomen irradiation without the confounding effects of concomitant hematopoietic syndrome that occur following whole-body irradiation. We then tested the utility of this platform to explore the effects of transient Wnt pathway activation on intestinal regeneration and animal recovery following induction of RIGS. Our results demonstrate that intestinal epithelial suppression of adenomatous polyposis coli (Apc) mitigates RIGS lethality in vivo after lethal ionizing radiation injury-induced intestinal epithelial damage. These results highlight the potential of short-term Wnt agonism as a therapeutic target and establish a platform to evaluate other strategies to stimulate intestinal regeneration after ionizing radiation damage.

Gut microbial dysbiosis is associated with development and progression of radiation enteritis during pelvic radiotherapy

Radiation enteritis (RE) is the most common complication of radiotherapy for pelvic irradiation receivers. Herein we investigated the alterations in gut microbial profiles and their association with enteritis in patients undergoing pelvic radiotherapy. Faecal samples were collected from 18 cervical cancer patients during radiotherapy. Microbiota profiles were characterized based on 16S rRNA sequencing using the Illumina HiSeq platform. Epithelial inflammatory response was evaluated using bacterial‐epithelial co‐cultures. Dysbiosis was observed among patients with RE, which was characterized by significantly reduced α‐diversity but increased β‐diversity, relative higher abundance of Proteobacteria and Gammaproteobacteria and lower abundance of Bacteroides.Coprococcus was clearly enriched prior to radiotherapy in patients who later developed RE. Metastat analysis further revealed unique grade‐related microbial features, such as more abundant Virgibacillus and Alcanivorax in patients with mild enteritis. Additionally, using bacterial‐epithelial co‐cultures, RE patient‐derived microbiota induced epithelial inflammation and barrier dysfunction, enhanced TNF‐α and IL‐1β expression compared with control microbiota. Taken together, we define the overall picture of gut microbiota in patients with RE. Our results suggest that dysbiosis of gut microbiota may contribute to development and progression of RE. Gut microbiota can offer a set of biomarkers for prediction, disease activity evaluation and treatment selection in RE.

Radiofrequency ablation in a patient with radiation enteritis: A case report

RATIONALE

Radiation enteritis (RE) is one of the serious complications caused by the radiotherapy and it can occur in any segment of the intestine, including small intestine, colon, and rectum. It can cause a number of serious problems of the intestine, such as chronic ulcers, bleeding, intestinal stenosis, intestinal fistula, and perforation. At present, there is no standard treatment guideline for the RE.

PATIENT CONCERNS

A 54-year-old male patient received surgery and chemotherapy for rectal cancer and radiofrequency ablation (RFA) for a single metastatic carcinoma of the liver. Three years later, he was diagnosed with recurrent lesion in the rectal anastomotic stoma and was treated with radiotherapy with a total dose of 70 Gy. Following this, he had persistent abdominal pain and diarrhea for 1 year.

DIAGNOSES

Colonoscopy confirmed a diagnosis of RE.

INTERVENTIONS

Since intestinal probiotics, intestinal mucosal protectants, antidiarrheal drugs, and other treatments were not effective; the patient was treated by RFA.

OUTCOMES

Clinical symptoms of the patient were gradually decreased after the RFA. Colonoscopy examination was performed 3 months later and intestinal mucosa was found to have healed well.

LESSONS

RFA is an effective treatment for patients with RE, and it is expected to be one of the standard treatments for the RE.

The Microbiome and Radiation Induced-Bowel Injury: Evidence for Potential Mechanistic Role in Disease Pathogenesis

Radiotherapy has played a major role in both the curative and palliative treatment of cancer patients for decades. However, its toxic effect to the surrounding normal healthy tissue remains a major drawback. In cases of intra-abdominal and/or pelvic malignancy, healthy bowel is inevitably included in the radiation field, causing undesirable consequences that subsequently manifest as radiation-induced bowel injury, which is associated with significant morbidity and mortality. The pathophysiology of radiation-induced bowel injury is poorly understood, although we now know that it derives from a complex interplay of epithelial injury and alterations in the enteric immune, nervous, and vascular systems in genetically predisposed individuals. Furthermore, evidence supporting a pivotal role for the gut microbiota in the development of radiation-induced bowel injury has been growing. In this review, we aim to appraise our current understanding of radiation-induced bowel injury and the role of the microbiome in its pathogenesis as well as prevention and treatment. Greater understanding of the relationship between the disease mechanism of radiation-induced bowel injury and gut microbiome might shed light on potential future prevention and treatment strategies through the modification of a patient's gut microbiome.

Incidence of radiation enteritis in cervical cancer patients treated with definitive radiotherapy versus adjuvant radiotherapy

Objective

The study aimed to evaluate the incidence of early and late radiation enteritis in cervical cancer patients receiving definitive or adjuvant radiotherapy (RT).

Materials and Methods

Three hundred and twenty-four cervical cancer patients receiving definite or adjuvant RT in our hospital from January 2010 to December 2012 were divided into definitive (132 patients) or adjuvant RT (192 patients) and performed detailed analysis.

Results

Early radiation enteritis was found in 54.3%, and late radiation enteritis was found in 17.9% of cervical patients. Early (P < 0.007) and late (P < 0.003) radiation enteritis appeared more frequently in patients treated with definitive RT than that with adjuvant RT. In the definitive RT group, incidence of both early and late radiation enteritis in the RT group was higher than in the radiochemotherapy (RCHT) group, and the difference was statistically significant (P < 0.004). Severe cases of late radiation enteritis (Grade 3 and 4) can be seen higher in the definitive radiation group (both the RT and RCHT group) than in the adjuvant radiation group, and the difference was statistically significant (P < 0.005).

Conclusion

The incidence of both early and late radiation enteritis in the definitive RT group is higher than in the adjuvant RT group. The occurrence of side effects was associated with the prolongation of total irradiation time due to necessary interruptions of RT. Methods to decrease the interruptions in the RT and the irradiated volume of the small bowel will further lessen enteric morbidity.

NADH protect against radiation enteritis by enhancing autophagy and inhibiting inflammation through PI3K/AKT pathway

Radiotherapy is an important method for cancer treatment but it has serious side-effects at high doses. One of the greatest challenges in radiotherapy is that radiation affects both healthy tissue and cancer tissues. For abdominal or pelvic lesions, the bowel is the most easily injured by irradiation. Radiation may cause radiation enteritis, intestinal inflammatory infiltration, or intestinal perforation. Coenzyme NADH involves in energy metabolism and transportation of nucleic acid, proteins and carbohydrates. In our study, NADH was used to protect the intestinal wall from irradiation injury in IEC-6 normal intestinal epithelial cells. By flow cytometry, we found that NADH can inhibit the cell death and the producing of reactive oxygen species (ROS). The immunofluorescence assay showed that cell autophagy was increased in the NADH group. Western blot data indicated that NADH promoted the microtubule associated protein 1A/1B-light chain 3(LC3)-I to LC3II and the expression of IL-1β and TNFα decreased in a dose dependent manner. Interestingly, a specific PI3K/AKT inhibitor (3MA) decreased the expression of inflammatory factors. In the animal experiment, after 12 Gy radiation, there were less TNFα and more LC3II in the RT+NADH group than that of RT group. Compared with the mock, there was no significant damage in the NADH group. Thus, our study provides the evidence that NADH may protect against radiation enteritis by suppressing inflammation and enhancing autophagy through PI3K/AKT pathway in normal intestinal cells.

Rs13293512 polymorphism located in the promoter region of let-7 is associated with increased risk of radiation enteritis in colorectal cancer

RE (Radiation enteritis) has been characterized by the inflammation reaction, and in this study, we aim to explore inflammatory cytokines and underlying mechanism involved in the pathogenesis of RE. Luciferase assay was performed to explore whether polymorphism affected the expression of let-7, and also validated let-7 directly regulated f IL-6 expression. Then Elisa was performed to study the mechanism of rs13293512 polymorphism associated with enteritis occurrence. And Western-blot and real-time PCR were performed to verify the relationship between let-7 and IL-6. 380 colorectal cancer patients were recruited, and all participants were genotyped. We found that occurrence probability of enteritis patients carried CC genotype (32%) was much higher than that in TT and TC groups (15%). In addition, we showed that the presence of the minor (C) allele of the polymorphism in the promoter region of let-7 substantially reduced the transcription activity of let-7, furthermore, we validated that let-7 directly regulated IL-6 expression by using luciferase reporter system. Moreover, IL-6 was highly expressed in peripheral blood and colonic mucosa samples genotyped as CC compared to those in TT and TC groups, furthermore, IL-6 was highly expressed in peripheral blood and colonic mucosa samples from participants with enteritis than without enteritis, whereas let-7 was highly expressed in peripheral blood and colonic mucosa samples genotyped as TT and TC compared to those in CC groups. Let-7 polymorphism (rs13293512) was associated with risk of RE in the colorectal cancer patients who received radiotherapy.

Concurrent Chemoradiation Affects the Clinical Outcome of Small Bowel Complications Following Pelvic Irradiation: Prospective Observational Study from a Regional Cancer Center

Background

To appraise the spectrum of small bowel complications following pelvic irradiation and to assess the clinical outcome and factors associated with adverse clinical outcome in these patients.

Methods

This descriptive clinical study was done for three years in a tertiary care center in South India. Patients managed for post-irradiation small bowel complications, irrespective of the indication for radiotherapy, were studied. Patients with associated non-gastrointestinal radiation toxicity, radiation proctitis, and radiation colitis were excluded. The parameters assessed were the range of small bowel complications, a comparison of operative and non-operative management, morbidity and mortality, the severity of complications in relation to the dose of radiotherapy, and various factors influencing the clinical outcome.

Results

A total of 50 patients were studied. Stricture and perforation peritonitis were the most common presentation (n=25; 50%). A majority of the patients (n=37; 74%) presented after six months following radiotherapy. Post-operative mortality was 16% (n=5). Age, body mass index (BMI), previous surgery, operative intervention, primary or adjuvant radiotherapy, concurrent chemoradiotherapy (CCRT), and various radiation protocols were not associated with adverse clinical outcomes with respect to overall mortality, the requirement of surgery, and operative mortality. However patients who were operated and those who received CCRT had a significantly longer mean intensive care unit (ICU) stay (3.51 days vs. 0.68 days; p = 0.0001) as well as overall mean hospital stay (14.87 days vs. 5.58 days; p = 0.001) and an insignificant mortality rate (16% vs. 15%; p = 0.4085).

Conclusion

The present study observed that the patients who were operated and those who received CCRT had significantly longer hospitalization and relatively higher mortality. Considering the fact that many of the patients who develop post-irradiation complications may not report back to the same center, the incidence of small bowel complications could be higher in reality, which ascertains the necessity for more precision in the radiation technique and operative care in developing countries.

Therapeutic role of glutamine in management of radiation enteritis: a meta-analysis of 13 randomized controlled trials

Objective

To systematically evaluate the clinical efficacy of glutamine in treating radiation enteritis in cancer patients treated with radiotherapy.

Methods

Electronic databases including Pubmed, Embase, the Cochrane library, and CNKI were systematically searched, until April 2016. Randomized controlled trials (RCT) of glutamine in the treatment of radiation enteritis in cancer patients were searched, and RevMan 5.3 software was used for Meta-analysis.

Results

A total of 13 RCTs were included, involving 979 patients. The results of meta-analysis showed that the total efficacy of glutamine was higher for patients with radiation enteritis compared with that in control group, however, there was no statistically significant difference(OR = 3.07, 95%CI: 0.79-11.96; P > 0.05). The combined ORs for all 5 grades(from grade 0 to grade 4) of radiation enteritis in patients receiving glutamine were 2.06, 1.35, 0.55, 0.62 and 0.59, respectively(P > 0.05 for all). Glutamine also failed to significantly improve the symptoms of radiation enteritis in terms of tenesmus, abdominal cramping and blood in bowel movement(P > 0.05).

Conclusions

Implementation of glutamine fails to improve the severity and symptoms in patients with radiation enteritis.

Recurrent scrotal edema in a patient with radiation enteritis: A case report

Since its introduction as an alternative treatment technique, radiotherapy has been increasingly used as the medical treatment of choice for patients with malignant tumors. However, radiotherapy is associated with a number of common, well-described side effects, which may compromise the quality of life of the patients. Scrotal edema is an infrequent complication in patients who undergo pelvic irradiation, which is suspected to be due to lymphatic obstruction. An extensive literature search found no previous case report describing this complication in patients receiving pelvic radiotherapy. Herein, we present a case of recurrent scrotal edema in a 59-year-old man with prostate cancer and radiation enteritis. Conservative therapy was applied and was successful in relieving the symptoms. To the best of our knowledge, this is the first case report of scrotal edema in a patient with radiation enteritis.

Transcriptional corepressor MTG16 regulates small intestinal crypt proliferation and crypt regeneration after radiation-induced injury

Myeloid translocation genes (MTGs) are transcriptional corepressors implicated in development, malignancy, differentiation, and stem cell function. While MTG16 loss renders mice sensitive to chemical colitis, the role of MTG16 in the small intestine is unknown. Histological examination revealed that Mtg16(-/-) mice have increased enterocyte proliferation and goblet cell deficiency. After exposure to radiation, Mtg16(-/-) mice exhibited increased crypt viability and decreased apoptosis compared with wild-type (WT) mice. Flow cytometric and immunofluorescence analysis of intestinal epithelial cells for phospho-histone H2A.X also indicated decreased DNA damage and apoptosis in Mtg16(-/-) intestines. To determine if Mtg16 deletion affected epithelial cells in a cell-autonomous fashion, intestinal crypts were isolated from Mtg16(-/-) mice. Mtg16(-/-) and WT intestinal crypts showed similar enterosphere forming efficiencies when cultured in the presence of EGF, Noggin, and R-spondin. However, when Mtg16(-/-) crypts were cultured in the presence of Wnt3a, they demonstrated higher enterosphere forming efficiencies and delayed progression to mature enteroids. Mtg16(-/-) intestinal crypts isolated from irradiated mice exhibited increased survival compared with WT intestinal crypts. Interestingly, Mtg16 expression was reduced in a stem cell-enriched population at the time of crypt regeneration. This is consistent with MTG16 negatively regulating regeneration in vivo. Taken together, our data demonstrate that MTG16 loss promotes radioresistance and impacts intestinal stem cell function, possibly due to shifting cellular response away from DNA damage-induced apoptosis and towards DNA repair after injury.

Three cases with active bleeding from radiation enteritis that were diagnosed with video capsule endoscopy without retention

Endoscopic exploration of the small bowel after pelvic radiation has limitations related to strong abdominal adhesion. It is often difficult to demonstrate the findings of radiation enteritis endoscopically, even with video capsule endoscopy (VCE) or double-balloon enteroscopy (DBE). We present our experience with three cases of radiation enteritis that were diagnosed using VCE and DBE, including their effective aspects. Radiation enteritis has not been diagnosed using conventional methods, and DBE may not accomplish deeper insertion into the ileum, although it is capable of both diagnosis and hemostasis. Therefore, VCE is thought to be the initial tool for the diagnosis of radiation enteritis when small bowel stenosis has not been previously detected and the risk of retention has been discussed.

Lactobacillus probiotic protects intestinal epithelium from radiation injury in a TLR-2/cyclo-oxygenase-2-dependent manner

BACKGROUND

The small intestinal epithelium is highly sensitive to radiation and is a major site of injury during radiation therapy and environmental overexposure.

OBJECTIVE

To examine probiotic bacteria as potential radioprotective agents in the intestine.

METHODS

8-week-old C57BL/6 wild-type or knockout mice were administered probiotic by gavage for 3 days before 12 Gy whole body radiation. The intestine was evaluated for cell-positional apoptosis (6 h) and crypt survival (84 h).

RESULTS

Gavage of 5×10⁷ Lactobacillus rhamnosus GG (LGG) improved crypt survival about twofold (p<0.01); the effect was observed when administered before, but not after, radiation. Conditioned medium (CM) from LGG improved crypt survival (1.95-fold, p<0.01), and both LGG and LGG-CM reduced epithelial apoptosis particularly at the crypt base (33% to 18%, p<0.01). LGG was detected in the distal ileal contents after the gavage cycle, but did not lead to a detectable shift in bacterial family composition. The reduction in epithelial apoptosis and improved crypt survival offered by LGG was lost in MyD88⁻/⁻, TLR-2⁻/⁻ and cyclo-oxygenase-2⁻/⁻ (COX-2) mice but not TLR-4⁻/⁻ mice. LGG administration did not lead to increased jejunal COX-2 mRNA or prostaglandin E2 levels or a change in number of COX-2-expressing cells. However, a location shift was observed in constitutively COX-2-expressing cells of the lamina propria from the villi to a position near the crypt base (villi to crypt ratio 80:20 for control and 62:38 for LGG; p<0.001). Co-staining revealed these COX-2-expressing small intestinal lamina propria cells to be mesenchymal stem cells.

CONCLUSIONS

LGG or its CM reduce radiation-induced epithelial injury and improve crypt survival. A TLR-2/MyD88 signalling mechanism leading to repositioning of constitutive COX-2-expressing mesenchymal stem cells to the crypt base is invoked.

Microbial influences on the small intestinal response to radiation injury

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.

RECENT FINDINGS

There is promise in the development and testing of new clinical biomarkers including serum citrulline. Toll-like receptor agonists and innate immune system signaling pathways including nuclear factor-kappa B profoundly alter intestinal epithelial cell apoptosis and crypt survival after radiation exposure. Germ-free conditions, probiotics and antibiotics are each identified as modifiers of disease development and course. A human study suggested that luminal microbiota composition may influence the host's intestinal response to radiation and may change in those developing postradiation diarrhea.

SUMMARY

New knowledge implies that investigations aimed at deciphering the microbiome-host interactions before and after small bowl radiation injury may eventually allow prediction of disease course and offer opportunities for the development of novel therapeutic or prophylactic strategies.

Intestinal obstruction by capsule endoscopy in a patient with radiation enteritis

BACKGROUND

Video capsule endoscopy is in widespread use as a diagnostic modality. Although capsule endoscopy is generally considered safe, several prior reports have documented capsules' failure to progress through narrowed areas of intestine. Symptomatic retention and obstruction by capsule endoscopy have not yet been reported in the setting of radiation enteritis.

METHODS

We report a case of a patient with a history of pelvic radiation who underwent capsule endoscopy to identify an occult intestinal bleeding source after conventional modalities were not diagnostic.

RESULTS

The patient was noted to have capsule retention several days longer than was expected, and video images of the distal bowel showed edema, narrowing, and ulceration consistent with radiation enteritis. The patient developed a symptomatic bowel obstruction requiring resection of this segment of bowel, including the impacted capsule.

CONCLUSION

A history of abdominal or pelvic irradiation in patients with occult gastrointestinal bleeding should serve as a relative contraindication to video capsule endoscopy. The risk of obstruction and possible need for surgical intervention should be clearly outlined for such patients if they are to undergo this diagnostic maneuver.

Postoperative enterocutaneous fistula: when to reoperate and how to succeed

An enterocutaneous fistula (ECF) is a potentially catastrophic postoperative complication. Although the morbidity and mortality associated with ECF have decreased over the past 50 years with modern medical and surgical care, the overall mortality is still surprisingly high, up to 39% in recent literature. It seems prudent, then, for every surgeon to have a thorough grasp of optimal treatment strategies for ECF to minimize their patients' mortality. Ultimately, the algorithm must begin with prevention. Once an ECF is diagnosed, the first step is to resuscitate and treat sepsis. The second is to control fistula output. The third step is to optimize the patient medically and nutritionally. The last step is definitive restoration of gastrointestinal continuity when necessary. Special mention is given in this article to exceptionally refractory fistulas such as those arising in the presence of inflammatory bowel disease and irradiated bowel. This plan gives a framework for the difficult task of successfully treating the postoperative ECF with a multidisciplinary approach.