Mucosal cytokine production in radiation-induced proctosigmoiditis compared with inflammatory bowel disease

Gut Microbiota-Derived 3-Hydroxybutyrate Blocks GPR43-Mediated IL6 Signaling to Ameliorate Radiation Proctopathy

Radiation proctopathy (RP) is a common complication of radiotherapy for pelvic malignancies with high incidence. RP accompanies by microbial dysbiosis. However, how the gut microbiota affects the disease remains unclear. Here, metabolomics reveals that the fecal and serous concentrations of microbiota-derived 3-hydroxybutyrate (3HB) are significantly reduced in RP mice and radiotherapeutic patients. Moreover, the concentration of 3HB is negatively associated with the expression of proinflammatory IL6 that is increased along with the severity of radiation damage. 3HB treatment significantly downregulates IL6 expression and alleviates IL6-mediated radiation damage. Irradiated cell-fecal microbiota co-culture experiments and in vivo assays show that such a radioprotection of 3HB is mediated by GPR43. Microbiome analysis reveals that radiation leads to a distinct bacterial community compared to untreated controls, in which Akkermansia muciniphila is significantly reduced in RP mice and radiotherapeutic patients and is associated with lower 3HB concentration. Gavage of A. muciniphila significantly increases 3HB concentration, downregulates GPR43 and IL6 expression, and ameliorates radiation damage. Collectively, these results demonstrate that the gut microbiota, including A. muciniphila, induce higher concentrations of 3HB to block GPR43-mediated IL6 signaling, thereby conferring radioprotection. The findings reveal a novel implication of the gut-immune axis in radiation pathophysiology, with potential therapeutic applications.

Combination of phytochemicals, including ginsenoside and curcumin, shows a synergistic effect on the recovery of radiation-induced toxicity

Radiotherapy is commonly used to treat solid cancers located in the pelvis. A considerable number of patients experience proctitis of varying severity, even for a considerable period after radiotherapy. These side effects are often long-lasting or progressively worsen despite multiple therapeutic efforts and are a primary cause of an unexpectedly low quality of life, even after successful cancer treatment. Therefore, this study evaluated the individual and combined efficacy of ginsenoside, curcumin, butyric acid, and sucralfate compounds in treating radiation-induced proctitis. While the candidate compounds did not affect the proliferation and migration of cancer cells, they promoted the recovery of cell activity, including motility. They exhibited anti-inflammatory effects on human dermal fibroblasts or human umbilical vein endothelial cells within in vitro disease models. When each compound was tested, curcumin and ginsenoside were the most effective in cell recovery and promoted the migration of human dermal fibroblasts and cell restoration of human umbilical vein endothelial cells. The combination of ginsenoside and curcumin resulted in cell migration recovery of approximately 54%. In addition, there was a significant improvement in the length of the endothelial tube, with an increase of approximately 25%, suggesting that the ginsenoside-curcumin-containing combination was the most effective against radiation-induced damage. Furthermore, studies evaluating the effects of combined treatments on activated macrophages indicated that the compounds effectively reduced the secretion of inflammatory cytokines, including chemokines, and alleviated radiation-induced inflammation. In conclusion, our study provides valuable insights into using curcumin and ginsenoside as potential compounds for the effective treatment of radiation-induced injuries and highlights the promising therapeutic benefits of combining these two compounds.

Clinical Management of Low Anterior Resection Syndrome: Review of the Current Diagnosis and Treatment

BACKGROUND

Low anterior resection syndrome (LARS) is a series of bowel dysfunction symptoms, including altered bowel frequency, irregular bowel rhythms, fecal incontinence, and constipation. LARS occurs in 80% of patients undergoing sphincter-preserving surgery, affecting patients' quality of life along with social avoidance. Different measurements and treatments have been raised to deal with LARS, but no systematic standard has been developed.

OBJECTIVE AND METHODS

To promote the standardization of clinical trials and clinical management of LARS, this review summarizes the latest findings up until 2023 regarding the diagnostic criteria, assessment protocols, and treatment modalities for postoperative LARS in rectal cancer.

RESULTS

The diagnostic criteria for LARS need to be updated to the definition proposed by the LARS International Collaborative Group, replacing the current application of the LARS score. In both clinical trials and clinical treatment, the severity of LARS should be assessed using at least one symptom assessment questionnaire, the LARS score or MSKCC BFI, and at least one scale related to quality of life. Anorectal manometry, fecoflowmetry, endoscopic ultrasonography, and pelvic floor muscle strength testing are recommended to be adopted only in clinical trials. After analysis of the latest literature on LARS treatment, a stepwise classification model is established for the standardized clinical management of LARS. Patients with minor LARS can start with first-line treatment, including management of self-behavior with an emphasis on diet modification and medication. Lamosetron, colesevelam hydrochloride, and loperamide are common antidiarrheal agents. Second-line management indicates multi-mode pelvic floor rehabilitation and transanal irrigation. Patients with major LARS should select single or several treatments in second-line management. Refractory LARS can choose antegrade enema, neuromodulation, or colostomy.

CONCLUSIONS

In clinical trials of LARS treatment between 2020 and 2022, the eligibility criteria and evaluation system have been variable. Therefore, it is urgent to create a standard for the diagnosis, assessment, and treatment of LARS. Failure to set placebos and differentiate subgroups are limitations of many current LARS studies. Randomized controlled trials comparing diverse therapies and long-term outcomes are absent, as well. Moreover, a new scale needs to be developed to incorporate the patient's perspective and facilitate outpatient follow-up. Though the establishment of a stepwise classification model for LARS treatment here is indispensable, the refinement of the guidelines may be improved by more standardized studies.

A ferroptosis-targeting ceria anchored halloysite as orally drug delivery system for radiation colitis therapy

Radiation colitis is the leading cause of diarrhea and hematochezia in pelvic radiotherapy patients. This work advances the pathogenesis of radiation colitis from the perspective of ferroptosis. An oral Pickering emulsion is stabilized with halloysite clay nanotubes to alleviate radiation colitis by inhibiting ferroptosis. Ceria nanozyme grown in situ on nanotubes can scavenge reactive oxygen species, and deferiprone was loaded into the lumen of nanotubes to relieve iron stress. These two strategies effectively inhibit lipid peroxidation and rescue ferroptosis in the intestinal microenvironment. The clay nanotubes play a critical role as either a medicine to alleviate colitis, a nanocarrier that targets the inflamed colon by electrostatic adsorption, or an interfacial stabilizer for emulsions. This ferroptosis-based strategy was effective in vitro and in vivo, providing a prospective candidate for radiotherapy protection via rational regulation of specific oxidative stress.

Released dsDNA-triggered inflammasomes serve as intestinal radioprotective targets

Objectives

Intestinal mucositis is the major side effect during abdominal or pelvic radiotherapy, but the underlying immunogen remains to be further characterised and few radioprotective agents are available. This study investigated the role of dsDNA-triggered inflammasomes in intestinal mucositis during radiotherapy.

Methods

Pro-inflammatory cytokines were detected by ELISA. Radiation-induced intestinal injury in mice was analyzed by means of survival curves, body weight, HE staining of intestines, and intestinal barrier integrity. Western blot, immunofluorescence staining, co-immunoprecipitation assay and flow cytometry were used to investigate the regulatory role of dsDNA on inflammasomes.

Results

Here, we show that a high level of IL-1β and IL-18 is associated with diarrhoea in colorectal cancer (CRC) patients during radiotherapy, which accounts for intestinal radiotoxicity. Subsequently, we found that the dose-dependently released dsDNA from the intestinal epithelial cells (IECs) serves as the potential immunogenic molecule for radiation-induced intestinal mucositis. Our results further indicate that the released dsDNA transfers into the macrophages in an HMGB1/RAGE-dependent manner and then triggers absent in melanoma 2 (AIM2) inflammasome activation and the IL-1β and IL-18 secretion. Finally, we show that the FDA-approved disulfiram (DSF), a newly identified inflammasome inhibitor, could mitigate intestinal radiotoxicity by controlling inflammasome.

Conclusion

These findings indicate that the extracellular self-dsDNA released from the irradiated IECs is a potential immunogen to stimulate immune cells and trigger the subsequent intestinal mucositis, while blunting the dsDNA-triggered inflammasome in macrophages may represent an exciting therapeutic strategy for side effects control during abdominal radiotherapy.

Management of Low Anterior Resection Syndrome (LARS) Following Resection for Rectal Cancer

INTRODUCTION

A total of 60-80% of patients undergoing rectal resection (mostly as a treatment for rectal cancer) suffer from a variety of partly severe functional problems despite preservation of the anal sphincter. These patients are summarized under the term low anterior resection syndrome (LARS). Preoperative radiotherapy, vascular dissection and surgical excision of the low rectum and mesorectum lead, alone or all together, to a significant impairment of colonic and (neo-) rectal motility. This results in a variety of symptoms (multiple defecation episodes, recurrent episodes of urge, clustering, incontinence, etc.) which are associated with severe impairment of quality of life (QOL).

METHODS

This narrative review summarizes the present state of knowledge regarding the pathophysiology of LARS as well as the evidence for the available treatment options to control the symptoms resulting from this condition.

RESULTS

A review of the literature (Medline, Pubmed) reveals a variety of treatment options available to control symptoms of LARS. Medical therapy, with or without dietary modification, shows only a modest effect. Pelvic floor rehabilitation consisting of muscle exercise techniques as well as biofeedback training has been associated with improvement in LARS scores and incontinence, albeit with limited scientific evidence. Transanal irrigation (TAI) has gained interest as a treatment modality for patients with LARS due to an increasing number of promising data from recently published studies. Despite this promising observation, open questions about still-unclear issues of TAI remain under debate. Neuromodulation has been applied in LARS only in a few studies with small numbers of patients and partly conflicting results.

CONCLUSION

LARS is a frequent problem after sphincter-preserving rectal surgery and leads to a marked impairment of QOL. Due to the large number of patients suffering from this condition, mandatory identification, as well as treatment of affected patients, must be considered during surgical as well as oncological follow-up. The use of a standardized treatment algorithm will lead to sufficient control of symptoms and a high probability of a marked improvement in QOL.

The role of colonic motility in low anterior resection syndrome

Low anterior resection syndrome (LARS) describes the symptoms and experiences of bowel dysfunction experienced by patients after rectal cancer surgery. LARS is a complex and multifactorial syndrome exacerbated by factors such as low anastomotic height, defunctioning of the colon and neorectum, and radiotherapy. There has recently been growing awareness and understanding regarding the role of colonic motility as a contributing mechanism for LARS. It is well established that rectosigmoid motility serves an important role in coordinating rectal filling and maintaining continence. Resection of the rectosigmoid may therefore contribute to LARS through altered distal colonic and neorectal motility. This review evaluates the role of colonic motility within the broader pathophysiology of LARS and outlines future directions of research needed to enable targeted therapy for specific LARS phenotypes.

Therapeutics in Radiation-induced Proctopathy: A Systematic Review

Malignant neoplasms are increasingly prevalent in the daily clinical practice. Up to 61% of patients with pelvic malignancies undergo pelvic radiotherapy in different doses, which may cause intestinal damage, and the rectum is the segment most frequently affected due to its fixed position in the pelvis. Currently, there are several strategies to minimize the effects of radiation on the tissues surrounding the neoplastic site; despite those strategies, radiotherapy can still result in serious damage to organs and structures, and these injuries accompany patients throughout their lives. One of the most common damages resulting from pelvic radiotherapy is acute proctitis.The diagnosis is confirmed by visualizing the rectal mucosa through rigid or flexible rectosigmoidoscopy and colonoscopy. The objective of the present study was to review the forms of radiation-induced proctopathytherapy, and to evaluate the results of each method to propose a standardization for the treatment of this pathology. Despite the prevalence of radiation-induced proctopathy, there is no definitive standardized treatment strategy so far. The first approach can be tried with local agents, such as mesalazine and formalin. For refractory cases, control can usually be achieved with argon plasma coagulation, hyperbaric oxygen, and radiofrequency ablation therapies. Regarding the study of radiation-induced proctopathy, there is a lack of robust studies with large samples and standardized therapies to be compared. There is a lack of double-blinded, randomized controlled studies to determine a definitive standard treatment algorithm.

Evaluation of mesalazine polymeric conjugate in the treatment of actinic proctitis in rats

Purpose:

The present study aimed at testing a new formulation of mesalazine linked to chondroitin sulfate and its components alone in the treatment of actinic proctitis in rats.

Methods:

Forty-seven female Wistar rats were submitted to pelvic radiation and divided into eight groups: control A, mesalazine A, chondroitin A, and conjugate A, gavage of the according substance two weeks after irradiation and sacrifice three weeks after oral treatment; control C, mesalazine C, chondroitin C, and conjugate C, sacrifice six weeks after oral treatment. The rectum was submitted to histological characterization for each of the findings: inflammatory infiltrate, epithelial degeneration, mucosal necrosis, and fibrosis.

Results:

The inflammatory infiltrate was more intense in chondroitin A, mesalazine A, and conjugate C. The collagen deposition was less intense in chondroitin A, and mesalazine A, and more intense in control C.

Conclusions:

Mesalazine and chondroitin alone were efficacious in inducing a delayed inflammatory response, hence reducing the late fibrosis. The conjugate was able to induce an ever more delayed inflammatory response.

Hyaluronic Acid Increases Anti-Inflammatory Efficacy of Rectal 5-Amino Salicylic Acid Administration in a Murine Colitis Model

5-amino salicylic acid (5-ASA) is a standard therapy for the treatment of mild to moderate forms of inflammatory bowel diseases (IBD) whereas more severe forms involve the use of steroids and immunosuppressive drugs. Hyaluronic acid (HA) is a naturally occurring non-sulfated glycosaminoglycan that has shown epithelium protective effects in experimental colitis recently. In this study, both 5-ASA (30 mg/kg) and HA (15 mg/kg or 30 mg/kg) were administered rectally and investigated for their potential complementary therapeutic effects in moderate or severe murine colitis models. Intrarectal treatment of moderate and severe colitis with 5-ASA alone or HA alone at a dose of 30 mg/kg led to a significant decrease in clinical activity and histology scores, myeloperoxidase activity (MPO), TNF-α, IL-6 and IL-1β in colitis mice compared to untreated animals. The combination of HA (30 mg/kg) and 5-ASA in severe colitis led to a significant improvement of colitis compared to 5-ASA alone. Combined rectal therapy with HA and 5-ASA could be a treatment alternative for severe cases of IBD as it was the only treatment tested that was not significantly different from the healthy control group. This study further underlines the benefit of searching for yet unexplored drug combinations that show therapeutic potential in IBD without the need of designing completely new drug entities.

Hyperbaric oxygen therapy as a complementary treatment for radiation proctitis: Useless or useful? – A literature review

Radiotherapy (RT) is the backbone of multimodality treatment of more than half of cancer cases. Despite new modern RT techniques, late complications may occur such as radiation proctitis (RP). The natural history of RP is unpredictable. Minor symptoms may resolve spontaneously or require conservative treatment. On the other hand, for similar and uncomplicated clinical contexts, symptoms may persist and can even be refractory to the progressive increase in treatment measures. Over the last decades, an enormous therapeutic armamentarium has been considered in RP, including hyperbaric oxygen therapy (HBOT). Currently, the evidence regarding the impact of HBOT on RP and its benefits is conflicting. Additional prospective and randomised studies are necessary to validate HBOT’s effectiveness in the ‘real world’ clinical practice. This article reviewed the relevant literature on pathophysiology, clinical presentation, different classifications and discuss RP management including a proposal for a therapeutic algorithm with a focus on HBOT.

Dietary Oat Bran Reduces Systemic Inflammation in Mice Subjected to Pelvic Irradiation

Patients undergoing radiotherapy to treat pelvic-organ cancer are commonly advised to follow a restricted fiber diet. However, reducing dietary fiber may promote gastrointestinal inflammation, eventually leading to deteriorated intestinal health. The goal of this study was to evaluate the influence of dietary fiber on radiation-induced inflammation. C57BL/6J male mice were fed a High-oat bran diet (15% fiber) or a No-fiber diet (0% fiber) and were either irradiated (32 Gy delivered in four fractions) to the colorectal region or only sedated (controls). The dietary intervention started at 2 weeks before irradiation and lasted for 1, 6, and 18 weeks after irradiation, at which time points mice were sacrificed and their serum samples were assayed for 23 cytokines and chemokines. Our analyses show that irradiation increased the serum cytokine levels at all the time points analyzed. The No-fiber irradiated mice had significantly higher levels of pro-inflammatory cytokines than the High-oat irradiated mice at all time points. The results indicate that a fiber-rich oat bran diet reduces the intensity of radiation-induced inflammation, both at an early and late stage. Based on the results, it seems that the advice to follow a low-fiber diet during radiotherapy may increase the risk of decreased intestinal health in cancer survivors.

Changrui enema inhibits inflammation-induced angiogenesis in acute radiation proctitis by regulating NF-κB and VEGF

Purpose

Changrui enema, a traditional Chinese medicine prescription, is used as a supplementary treatment for acute radiation proctitis (ARP). Herein we explored the inhibition effects of Changrui enema on NF-κB and VEGF in ARP mice.

Methods

A total of 120 C57BL/6 mice were divided randomly into normal mice group, ARP mice group, western medicine enema group (dexamethasone combined with gentamicin), and Changrui enema group. ARP mice were established by pelvic local irradiation. The expression of IL-1β, NF-κB, VEGF, AQP1, AQP3, p-ERK1/2 and p-JNK was determined by immunohistochemistry or western blot.

Results

The study firstly found that Changrui enema alleviated ARP mice. The expression of IL-1β, NF-κB, VEGF, AQP1 and p-ERK1/2 was increased in ARP mice, and was reserved by Changrui enema. However, the expression of AQP3 and p-JNK was decreased in ARP mice, and was up-regulated by Changrui enema.

Conclusions

Changrui enema is an effective treatment with fewer side effects for ARP. The mechanism of Changrui enema may be related to the inhibition of inflammation-induced angiogenesis. Changrui enema inhibits IL-1β and NF-κB expression as well as VEGF expression. Interestingly, AQP1 promotes angiogenesis, while AQP3 inhibits inflammation. Changrui enema probably inhibits AQP1 expression by down-regulating p-ERK1/2, and improves AQP3 expression by up-regulating p-JNK.

Effect of a bioactive product SEL001 from Lactobacillus sakei probio65 on gut microbiota and its anti-colitis effects in a TNBS-induced colitis mouse model

This study underpins the therapeutic potential of SEL001, a bioactive product isolated from Lactobacillus sakei probio65, in terms of its anti-inflammatory properties and its effect on gut-microbiota in a TNBS-induced ulcerative colitis mouse model. Ulcerative colitis was developed in mice by intra rectal administration of trinitrobenzene sulfonic acid. Bioactive product SEL001 (50 mg/kg b.w.) was administered orally. Myeloperoxidase activity was measured using 3,3', 5,5'-tetramethylbenzidine. The entire colon was sampled for post-mortem clinical assessment. Colonic injury was assessed through histological and histomorphometric examinations. The 454 pyrosequencing and QIIME pipeline were used for gut microbiota analysis and statistical analysis were conducted using R. mRNA extraction from colon tissue and RT-PCR approaches were employed to determine the changes in the level of specific biomarker genes associated with UC. The results depict that SEL001 significantly lowered pro-inflammatory cytokines, including CD4, TNF-α, and interleukin-6. Examination of clinical and histopathological traits revealed that SEL001 was effective and potent in reducing the inflammatory signatures of UC to a similar extent as did by the standard drug mesalamine (5-ASA). Pyro-sequencing 16S data revealed that the reduction in the major member of phylum Firmicutes, which has been previously associated with a higher risk of UC. The SEL001, an anti-inflammatory bioactive product originated from a probiotic strain L. sakei probio65 could be an alternative therapeutic agent for treatment of UC.

Ethyl pyruvate inhibits LPS induced IPEC-J2 inflammation and apoptosis through p38 and ERK1/2 pathways

The endotoxin of Gram-negative bacteria threatens the intestinal health of livestock. Ethyl pyruvate (EP) has been shown to regulate intestinal immunity and protect against cell and tissue damage. In this study, it was first verified that EP could reduce the secretion of IL-8, TNF-α, IL-6 and IL-1β in LPS-induced IPEC-J2 cells. Then, we used RNA sequencing (RNA-seq) to analyze the differentially expressed genes (DEGs) of inflammatory factors induced by LPS in IPEC-J2 cells. It was found that LPS induced the upregulation of 377 genes and the downregulation of 477 genes compared to Vehicle; LPS+EP induced the upregulation of 258 genes and the downregulation of 240 genes compared to Vehicle; and LPS+EP induced the upregulation of 373 genes and the downregulation of 188 genes compared to LPS (fold change > 1.5 and FDR < 0.01). Their enrichment pathways included the MAPK signaling pathway, PI3K-Akt signaling pathway, Toll-like receptor signaling pathway, and other pathways. Furthermore, the mRNA level of cytokines associated with inflammation and apoptosis enriched in the MAPK pathway was verified by qRT-PCR. Western blots and immunofluorescence revealed that EP significantly inhibited phosphorylated p38 and phosphorylated-ERK1/2 protein expression levels (P < 0.05). The apoptosis due to LPS reduced by EP was significantly inhibited, as shown by Annexin V-FITC/PI staining. According to the results, EP inhibited the expression of IL-8, TNF-α, IL-6 and IL-1β as well as apoptosis by inhibiting the phosphorylation of p38 and ERK1/2 in LPS-induced IPEC-J2 cells.

A case report of endoscopic therapy for radiation-induced hemorrhagic gastritis in patient with recurrent hepatocellular carcinoma

RATIONALE

Radiation-induced hemorrhagic gastritis is an infrequent cause of upper gastrointestinal bleeding and difficult to manage. The current standard treatment has not been well established.

PATIENT CONCERNS

We described a 32-year-old male patient with hemorrhagic gastritis induced by external radiotherapy for hepatocellular carcinoma recurrence.

DIAGNOSES

The endoscopic examination showed a diffuse area of bleeding in the gastric antrum.

INTERVENTIONS

After failure of conventional hemostasis treatment, we successfully stopped the hemorrhage with repeated endoscopic argon plasma coagulation (APC) combined with low-dose polyglycerol sclerotherapy.

OUTCOMES

The patient was followed up for 6 months to date without recurrence.

LESSONS

Based on this case, we think that endoscopic APC combined with low-dose polidocanol sclerotherapy can be tried as a treatment for potentially life-threatening radiation-induced hemorrhagic gastritis.

Effect of recombinant Trichinella spiralis cysteine proteinase inhibitor on TNBS-induced experimental inflammatory bowel disease in mice

Inflammatory bowel disease (IBD) is a chronic autoimmune disease with a high recurrence rate. Ulcerative colitis (UC) and Crohn's disease (CD) are two types of IBD. At present, parasite-derived cysteine protease inhibitors have received extensive attention from researchers, and experiments have confirmed that these protease have an effect on certain autoimmune diseases. So we conducted experiments to investigate the effect of Trichinella spiralis cysteine protease inhibitors on TNBS-induced mouse CD models. In this experiment, 72 male BALB/c mice aged 6-8 weeks were randomly divided into two groups: prevention group and therapy group. The mice were sacrificed and harvested on the 7th day after the model was established to measure the changes of various indicators of colitis. The comparison of the TsCystatin + TNBS group with the PBS + TNBS group showed that the DAI score, MPO activity, and colonic macroscopic and microscopic damage significantly reduced, IFN-γ significantly decreased, IL-4 expression increased, and NF-κB expression decreased. The percentage of CD4+CD25+Foxp3+ Treg and CD8+CD28- Treg in spleen, and the proportion of CD4+/CD8+ Treg cells decreased. In the therapy group, we found no significant difference between the TNBS+PBS group and TNBS + TsCystatin group. Treatment with TsCystatin exerted a good intervention effect on the TNBS-induced mouse CD model. TsCystatin possibly induced a Th2-type immune response in the body, which balanced the Th1-type immune response induced by TNBS administration, thereby relieving colitis.

Effect of two recombinant Trichinella spiralis serine protease inhibitors on TNBS-induced experimental colitis of mice

Inflammatory bowel disease (IBD), which includes ulcerative colitis and Crohn's disease (CD), is a chronic autoimmune disease. Parasitic infections and their products have been shown to have protective effects on autoimmune diseases, including IBD. In this experiment, 96 male BALB/c mice aged 6-8 weeks were divided randomly into two large groups: prevention and therapy. The changes in the various indicators of colitis were detected to demonstrate that Trichinella spiralis serine protease inhibitors can relieve the inflammatory severity of 2,4,6-trinitrobenzenesulphonic acid solution (TNBS)-induced colitis and to explore possible immunological mechanisms. Results showed that the disease activity index (DAI) score, myeloperoxidase (MPO) activity, macroscopic and microscopic damage degrees of colon all decreased significantly, interferon (IFN)-γ expression decreased, interleukin (IL)-4 expression increased, nuclear factor kappa B (NF)-κB expression decreased and the percentage of CD4⁺ CD25⁺ forkhead box protein 3 (FoxP3⁺ ) regulatory T cells (T_reg ) cells in the spleen. MLN increased significantly compared to the phosphate-buffered saline (PBS)/2,4,6-trinitrobenzenesulphonic acid solution (TNB) group. We found the same results with the T. spiralis Kazal-type serine protease inhibitors (TsKaSPI)+TNBS and TsAdSPI+TNBS groups in the large prevention group and the large therapy group, compared to the TNBS+PBS group with the TNBS+TsKaSPI and TNBS+TsAdSPI groups. Immunization with TsKaSPI and TsAdSPI on the CD models showed an intervention effect, possibly because TsKaSPI and TsAdSPI induced a T helper type 2 (Th2)-type immune response and balanced the TNBS-induced Th1-type immune response.

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.

The protective effects of Bacillus licheniformis preparation on gastrointestinal disorders and inflammation induced by radiotherapy in pediatric patients with central nervous system tumor

PURPOSE

we studied the effect of Bacillus licheniformis preparation (ZCS) on CNST (central nervous system tumor) patients undergoing the gastrointestinal symptoms and inflammation induced by radiotherapy.

MATERIALS AND METHODS

160 CNST patients with craniospinal irradiation (CSI) treatment were divided into experiment and control group. The experiment group patients took one capsule per time of ZCS and three times a day until the end of radiotherapy, starting one day before radiotherapy. While the patients in control group were administrated placebo without any probiotics. Serum from one day before radiotherapy and the first day after radiotherapy were collected to measure the ET, CRP, TNF-α, IL-1β and IL-6.

RESULTS

More than 70% CNST pediatric patients suffered from different degrees of gastrointestinal symptoms after radiotherapy, including mouth ulcer, nausea, vomiting, abdominal pain and diarrhea. And there was an obviously increased of serum ET, TNF-α, IL-1β, IL-6 and CRP after RT. Importantly, a markedly decreased of ET, CRP and inflammatory cytokines were detected in the experiment group comparing to the control group after radiotherapy, as well as the relief of the gastrointestinal symptoms. However, improvement of probiotics (or ZCS) of the survival rate of CNST children and the recurrence of tumor are not observed in this study.

CONCLUSIONS

Prophylactically administrated ZCS during radiotherapy for CNST patients can relieve RT-related gastrointestinal symptoms and inflammatory reaction.

Radiation induces proinflammatory dysbiosis: transmission of inflammatory susceptibility by host cytokine induction

OBJECTIVE

Radiation proctitis (RP) is a complication of pelvic radiotherapy which affects both the host and microbiota. Herein we assessed the radiation effect on microbiota and its relationship to tissue damage using a rectal radiation mouse model.

DESIGN

We evaluated luminal and mucosa-associated dysbiosis in irradiated and control mice at two postradiation time points and correlated it with clinical and immunological parameters. Epithelial cytokine response was evaluated using bacterial-epithelial co-cultures. Subsequently, germ-free (GF) mice were colonised with postradiation microbiota and controls and exposed to radiation, or dextran sulfate-sodium (DSS). Interleukin (IL)-1β correlated with tissue damage and was induced by dysbiosis. Therefore, we tested its direct role in radiation-induced damage by IL-1 receptor antagonist administration to irradiated mice.

RESULTS

A postradiation shift in microbiota was observed. A unique microbial signature correlated with histopathology. Increased colonic tumor necrosis factor (TNF)α, IL-1β and IL-6 expression was observed at two different time points. Adherent microbiota from RP differed from those in uninvolved segments and was associated with tissue damage. Using bacterial-epithelial co-cultures, postradiation microbiota enhanced IL-1β and TNFα expression compared with naïve microbiota. GF mice colonisation by irradiated microbiota versus controls predisposed mice to both radiation injury and DSS-induced colitis. IL-1 receptor antagonist administration ameliorated intestinal radiation injury.

CONCLUSIONS

The results demonstrate that rectal radiation induces dysbiosis, which transmits radiation and inflammatory susceptibility and provide evidence that microbial-induced radiation tissue damage is at least in part mediated by IL-1β. Environmental factors may affect the host via modifications of the microbiome and potentially allow for novel interventional approaches via its manipulation.

Radiation Therapy Did Not Induce Long-Term Changes in Rectal Mucosa: Results From the Randomized Scandinavian Prostate Cancer Group 7 Trial

PURPOSE

To investigate long-term changes in the rectal mucosa after curative external beam radiation therapy in the treatment of prostate cancer.

METHODS AND MATERIALS

In the Scandinavian Prostate Cancer Group 7 trial, 880 men with locally advanced prostate cancer were randomized to hormonal therapy alone versus hormonal therapy plus radiation therapy to 70 Gy. A subcohort from this trial being randomized at our center (n=178) was invited to a study on late anorectal side effects during 2003-2005, approximately 5 years after treatment, including measuring health-reported quality of life and physician-assessed toxicity score by the Late Effects Normal Tissue Task Force/Subjective, Objective, Management, Analytic (LENT/SOMA) and European Organization for Research and Treatment of Cancer/Radiation Therapy Oncology Group score. Sixty-seven patients had a rectal mucosa biopsy. Sixty-four biopsies were included in the final analysis, of which 33 patients were randomized to hormonal treatment and 31 to hormonal treatment plus radiation therapy. The presence of fibrosis, number of capillaries, and lymphocyte infiltration was then evaluated by light microscopy.

RESULTS

The group receiving radiation therapy had significantly higher LENT/SOMA and function/bother scale scores than the group that only received hormonal treatment, but there was no significant difference in the presence of fibrosis, ectasia, number of capillaries in the lamina propria, or lymphocyte infiltration between the groups.

CONCLUSION

Radiation therapy to 70 Gy to the prostate does not induce long-term microscopic mucosal changes in the rectum 5 years after treatment. This is in contrast to the general assumption that structural changes, including fibrosis, seen after radiation therapy include the mucosa. We speculate that the main late effects of radiation therapy on the structure of the rectum are located in the deeper layers of the rectal wall than the mucosa.

Low Triiodothyronine Syndrome in Patients With Radiation Enteritis: Risk Factors and Clinical Outcomes an Observational Study

The implications of low triiodothyronine syndrome (LT3S) in patients with radiation enteritis (RE) have not been properly investigated. As such, we conducted this cohort study to investigate the association between LT3S and RE, to explore the etiology of LT3S in RE, to evaluate the clinical features and clinical outcomes of LT3S patients, and to inspect the correlation of clinical variables and LT3S in RE.This prospective study included 39 RE patients. Medical records and various laboratory parameters (including thyroidal, tumorous, nutritional, and radiotherapy variables) were collected in all participants.Our results showed that the incidence of LT3S was 84.6% in patients with RE. Total protein (71.7 ± 5.7 vs 63.2 ± 9.6 g/L, P = 0.04) and albumin (ALB, 46.0 ± 4.6 vs 38.7 ± 5.3 g/L, P = 0.01) were significantly lower in LT3S group compared with those in euthyroid group. Standard thyroid-stimulating hormone index (-0.89 ± 2.11 vs -2.39 ± 1.33, P = 0.03) and sum activity of deiodinases (19.74 ± 4.19 vs 12.55 ± 4.32 nmol/L, P = 0.01) were significantly lower in LT3S group. Patients with LT3S suffered longer duration of hospitalization (48.25 ± 23.29 days in LT3S vs 26.75 ± 10.56 days in euthyroid, P = 0.036). Low serum ALB (β = 0.694, 95% CI = 0.007-0.190, P = 0.037) was the only significant predictor of LT3S.LT3S was common in RE patients. A hypodeiodination condition and a potential pituitary-thyrotroph dysfunction might play a role in the pathophysiology of LT3S in RE. Worse nutritional status and clinical outcomes were confirmed in RE patients with LT3S. Furthermore, total protein and ALB were observed as protective and differentiating parameters of LT3S in RE. In summary, this was the 1st investigation to evaluate the clinical correlation between RE and LT3S, investigate the prevalence of LT3S in RE, and explore the pathogenesis of LT3S, despite the limitation of a relatively small sample size. These results will hopefully encourage future research to place greater emphasis on early identification of LT3S in RE patients.

Salmonella infection inhibits intestinal biotin transport: cellular and molecular mechanisms

Infection with the nontyphoidal Salmonella is a common cause of food-borne disease that leads to acute gastroenteritis/diarrhea. Severe/prolonged cases of Salmonella infection could also impact host nutritional status, but little is known about its effect on intestinal absorption of vitamins, including biotin. We examined the effect of Salmonella enterica serovar Typhimurium (S. typhimurium) infection on intestinal biotin uptake using in vivo (streptomycin-pretreated mice) and in vitro [mouse (YAMC) and human (NCM460) colonic epithelial cells, and human intestinal epithelial Caco-2 cells] models. The results showed that infecting mice with wild-type S. typhimurium, but not with its nonpathogenic isogenic invA spiB mutant, leads to a significant inhibition in jejunal/colonic biotin uptake and in level of expression of the biotin transporter, sodium-dependent multivitamin transporter. In contrast, infecting YAMC, NCM460, and Caco-2 cells with S. typhimurium did not affect biotin uptake. These findings suggest that the effect of S. typhimurium infection is indirect and is likely mediated by proinflammatory cytokines, the levels of which were markedly induced in the intestine of S. typhimurium-infected mice. Consistent with this hypothesis, exposure of NCM460 cells to the proinflammatory cytokines TNF-α and IFN-γ led to a significant inhibition of biotin uptake, sodium-dependent multivitamin transporter expression, and activity of the SLC5A6 promoter. The latter effects appear to be mediated, at least in part, via the NF-κB signaling pathway. These results demonstrate that S. typhimurium infection inhibits intestinal biotin uptake, and that the inhibition is mediated via the action of proinflammatory cytokines.

Early hematologic changes during prostate cancer radiotherapy predictive for late urinary and bowel toxicity

BACKGROUND

The primary objective of the study was to identify early hematologic changes predictive for radiotherapy (RT)-associated genitourinary and gastrointestinal toxicity.

METHODS

In a group of 91 prostate cancer patients presenting for primary (n = 51) or postoperative (n = 40) curative RT, blood samples (blood count, acute phase proteins, and cytokines) were analyzed before (T1), three times during (T2-T4), and 6-8 weeks after (T5) radiotherapy. Before RT (baseline), on the last day (acute toxicity), a median of 2 months and 16 months (late toxicity) after RT, patients responded to a validated questionnaire (Expanded Prostate Cancer Index Composite). Acute score changes > 20 points and late changes > 10 points were considered clinically relevant.

RESULTS

Radiotherapy resulted in significant changes of hematologic parameters, with the largest effect on lymphocytes (mean decrease of 31-45 %) and significant dependence on target volume. C-reactive protein (CRP) elevation > 5 mg/l and hemoglobin level decrease ≥ 5 G/1 at T2 were found to be independently predictive for acute urinary toxicity (p < 0.01, respectively). CRP elevation was predominantly detected in primary prostate RT (p = 0.02). Early lymphocyte level elevation ≥ 0.3G/l at T2 was protective against late urinary and bowel toxicity (p = 0.02, respectively). Other significant predictive factors for late bowel toxicity were decreasing hemoglobin levels (cut-off ≥ 5 G/l) at T2 (p = 0.04); changes of TNF-α (tumor necrosis factor; p = 0.03) and ferritin levels (p = 0.02) at T5. All patients with late bowel toxicity had interleukin (IL)-6 levels < 1.5 ng/l at T2 (63 % without; p = 0.01).

CONCLUSION

Early hematologic changes during prostate cancer radiotherapy are predictive for late urinary and bowel toxicity.

Total glucosides of peony attenuates 2,4,6-trinitrobenzene sulfonic acid/ethanol-induced colitis in rats through adjustment of TH1/TH2 cytokines polarization

The present study is to investigate effects of total glucosides of peony (TGP) on 2,4,6-trinitrobenzene sulfonic acid (TNBS)/ethanol-induced colitis in rats and to explore potential clinical use of TGP for treatment of inflammatory bowel disease. Sixty Sprague-Dawley rats were randomly grouped into normal controls, model controls, sulfasalazine (SASP) controls (100 mg/kg/day), and low, medium, and high-dose TGP groups (25, 50, and 100 mg/kg/day, respectively). 24 h following colonic instillation of TNBS, TGP, and SASP were given by gastric gavage three times a day for 7 days. Disease activity index (DAI), colon macroscopic damage index (CMDI), histopathological score (HPS), and myeloperoxidase (MPO) activity were evaluated. Levels of serum TNF-α, IL-1β, and IL-10 were measured by ELISA, and expression of TNF-α, IL-1β, and IL-10 mRNA and protein in colonic tissues was detected by RT-PCR and western blot, respectively. Compared with rats in the model controls, TGP (50 or 100 mg/kg/day)-treated rats with TNBS/ethanol-induced colitis showed significant improvements of DAI, CMDI, HPS, and MPO activity. Moreover, administration of TGP (50 or 100 mg/kg/day) decreased the up-regulated levels of serum TNF-α and IL-1β, and expression of TNF-α and IL-1β mRNA and protein in colonic tissues, and increased the serum IL-10 and colonic IL-10 mRNA and protein level. And there was no significant difference compared with administration of SASP (P > 0.05). TGP attenuates TNBS/ethanol-induced colitis in rats and its efficacy is similar to SASP, the potential mechanism might be related to the adjustment of Th1/Th2 cytokines polarization by decreasing pro-inflammatory cytokine TNF-α and IL-1β, and increasing anti-inflammatory cytokine IL-10.

Lactobacillus acidophilus attenuates downregulation of DRA function and expression in inflammatory models

Probiotics, including Lactobacilli, are commensal bacteria that have been used in clinical trials and experimental models for the prevention and treatment of diarrheal disorders. Our previous studies have shown that Lactobacillus acidophilus (LA) and its culture supernatant (CS) stimulated Cl(-)/HCO3 (-) exchange activity, acutely via an increase in the surface levels of downregulated in adenoma (DRA, SLC26A3) and in long-term treatments via increasing its expression involving transcriptional mechanisms. However, the role of LA in modulating DRA activity under inflammatory conditions is not known. Current in vitro studies using human intestinal epithelial Caco-2 cells examined the efficacy of LA or its CS in counteracting the inhibitory effects of interferon-γ (IFN-γ) on Cl(-)/HCO3 (-) exchange activity. Pretreatment of cells with LA or LA-CS for 1 h followed by coincubation with IFN-γ significantly alleviated the inhibitory effects of IFN-γ on Cl(-)/HCO3 (-) exchange activity. In the in vivo model of dextran sulfate sodium-induced experimental colitis (3% in drinking water for 7 days) in C57BL/6J mice, administration of live LA (3 × 10(9) colony-forming units) via oral gavage attenuated colonic inflammation. LA administration also counteracted the colitis-induced decrease in DRA mRNA and protein levels. Efficacy of LA or its secreted soluble factors in alleviating inflammation and inflammation-associated dysregulation of DRA activity could justify their therapeutic potential in inflammatory diarrheal diseases.

Investigation into the role of the cholinergic system in radiation-induced damage in the rat liver and ileum

It has been previously shown that acetylcholine (ACh) may affect pro-inflammatory and anti-inflammatory cytokines. The role of the cholinergic system in radiation-induced inflammatory responses and tissue damage remains unclear. Therefore, the present study was designed to determine the radio-protective properties of the cholinergic system in the ileum and the liver of rats. Rats were exposed to 8-Gy single-fraction whole-abdominal irradiation and were then decapitated at either 36 h or 10 d post-irradiation. The rats were treated either with intraperitoneal physiological saline (1 ml/kg), physostigmine (80 µg/kg) or atropine (50 μg/kg) twice daily for 36 h or 10 d. Cardiac blood samples and liver and ileal tissues were obtained in which TNF-α, IL-1β and IL-10 levels were assayed using ELISA. In the liver and ileal homogenates, caspase-3 immunoblots were performed and myeloperoxidase (MPO) activity was analyzed. Plasma levels of IL-1β and TNF-α increased significantly following radiation (P < 0.01 and P < 0.001, respectively) as compared with non-irradiated controls, and physostigmine treatment prevented the increase in the pro-inflammatory cytokines (P < 0.01 and P < 0.001, respectively). Plasma IL-10 levels were not found to be significantly changed following radiation, whereas physostigmine augmented IL-10 levels during the late phase (P < 0.01). In the liver and ileum homogenates, IL-1β and TNF-α levels were also elevated following radiation, and this effect was inhibited by physostigmine treatment but not by atropine. Similarly, physostigmine also reversed the changes in MPO activity and in the caspase-3 levels in the liver and ileum. Histological examination revealed related changes. Physostigmine experiments suggested that ACh has a radio-protective effect not involving the muscarinic receptors.

Successful treatment of intractable bleeding caused by radiation-induced hemorrhagic gastritis using oral prednisolone: a case report

Radiation-induced hemorrhagic gastritis is an intractable and dangerous condition. We describe a 59-year-old female patient with radiation-induced hemorrhagic gastritis. The patient underwent postoperative radiation therapy with a dose of 54 Gy in 30 fractions after a radical operation for a Klatskin tumor. Radiation volume included the gastric antrum. Approximately three months after radiation therapy, she was admitted for melena and anemia. Esophagogastroduodenoscopy showed an area of bleeding in the gastric antrum that was so diffuse that effective laser coagulation was not feasible. After failure of various treatments and transfusion of 7,040 mL of packed red blood cells, we successfully stopped the hemorrhage using oral prednisolone treatment. Based on this case, we think that oral prednisolone treatment can be tried as a first treatment for potentially life-threatening radiation-induced hemorrhagic gastritis.

Insight into mucinous colorectal carcinoma: clues from etiology

The prognostic impact of mucinous carcinoma (MC) in colorectal cancer (CRC) has been subject to debate ever since the introduction of the classification of tumors according to their histological differentiation. MC is a distinct clinical and pathological entity within the spectrum of CRC and accounts for approximately 10-15 % of cases. Factors involved in MC development have not been completely understood, but clinical observations may lead to a better insight into the etiology of MC. In this article, we provide an in-depth review of the literature regarding etiological aspects of MC. We show that there are worldwide differences in the prevalence of MC, with low rates in Asian countries and higher rates in the western world. Moreover, MC is more commonly diagnosed in patients suffering from inflammatory bowel diseases or Lynch syndrome and an increased rate of MC is observed in patients with radiotherapy-induced CRCs. These findings are suggestive of a different oncogenic development. Identification of conditions that are associated with MC generates insight into the etiological pathways leading to the development of this special subtype.

Remote ischemic preconditioning as treatment for non-ischemic gastrointestinal disorders: Beyond ischemia-reperfusion injury

Common gastrointestinal diseases such as radiation enteritis (RE), acute pancreatitis, inflammatory bowel diseases (IBD) and drug-induced hepatotoxicity share pathophysiological mechanisms at the molecular level, mostly involving the activation of many pathways of the immune response, ultimately leading to tissue injury. Increased oxidative stress, inflammatory cytokine release, inflammatory cell infiltration and activation and the up-regulation of inflammatory transcription factors participate in the pathophysiology of these complex entities. Treatment varies in each specific disease, but at least in the cases of RE and IBD immunosuppressors are effective. However, full therapeutic responses are not always achieved. The pathophysiology of ischemia-reperfusion (IR) injury shares many of these mechanisms. Brief and repetitive periods of ischemia in an organ or limb have been shown to protect against subsequent major IR injury in distant organs, a phenomenon called remote ischemic preconditioning (RIP). This procedure has been shown to protect the gut, pancreas and liver by modulating many of the same inflammatory mechanisms. Since RIP is safe and tolerable, and has shown to be effective in some recent clinical trials, I suggest that RIP could be used as a physiologically relevant adjunct treatment for non-ischemic gastrointestinal inflammatory conditions.

The challenges of stratifying patients for trials in inflammatory bowel disease

Immunotherapy with biological agents or small molecules is revolutionising the treatment of chronic inflammatory disease in humans; however, a significant proportion of patients fail to respond or lose responsiveness. This is particularly evident in inflammatory bowel disease (IBD), a group of chronic, immune-mediated disorders of the gastrointestinal tract. Different responsiveness to treatment in IBD can be explained by substantial disease heterogeneity, which is being increasingly recognised by genetic and immunological studies. The current enthusiasm for stratified medicine suggests that it may become possible to identify clinical, immunological, biochemical or genetic biomarkers to target immunotherapy to patients more likely to respond. Here, we identify and highlight the opportunities and the challenges of this strategy in the context of IBD.

Treatment of radiation-induced hemorrhagic gastritis with prednisolone: A case report

Radiation-induced gastritis is an infrequent cause of gastrointestinal bleeding. It is a serious complication arising from radiation therapy, and the standard treatment method has not been established. The initial injury is characteristically acute inflammation of gastric mucosa. We presented a 46-year-old male patient with hemorrhagic gastritis induced by external radiotherapy for metastatic retroperitoneal lymph node of hepatocellular carcinoma. The endoscopic examination showed diffuse edematous hyperemicmucosa with telangiectasias in the whole muscosa of the stomach and duodenal bulb. Multiple hemorrhagic patches with active oozing were found over the antrum. Anti-secretary therapy was initiated for hemostasis, but melena still occurred off and on. Finally, he was successfully treated by prednisolone therapy. We therefore strongly argue in favor of perdnisolone therapy to effectively treat patients with radiation-induced hemorrhagic gastritis.

[Establishment and evaluation of a rat model of ulcerative colitis with syndrome of dampness stagnancy due to spleen deficiency]

OBJECTIVE

To establish a rat model of ulcerative colitis with syndrome of spleen deficiency and dampness stagnancy.

METHODS

Sixty rats were divided into normal control group, ulcerative colitis group, ulcerative colitis with syndrome of spleen deficiency and dampness stagnancy group (model group) and strengthening spleen for resolving dampness group. Ulcerative colitis in rats was induced by enema containing trinitrobenzene sulfonic acid (TNBS) and ethanol. The rats in the model group were suffered from standing in water, limiting sleeping time and abnormal diet based on administration of TNBS and ethanol. The rats in the spleen strengthening and dampness resolving group were gastrically administered with Shenlin Baizhu Powder, a compound traditional Chinese herbal medicine. Symptoms, signs and pathological changes in colon tissue of rats were observed after modeling. The levels of interleukin (IL)-6, IL-8 and tumor necrosis factor-α (TNF-α) in serum of rats were measured by enzyme-linked immunosorbent assay.

RESULTS

The rats in the model group showed lethargy, poor appetite, loss of energy, diarrhea and bloody stool. Their body weight decreased significantly compared with the normal control group, and similar changes were found in the comparison of food intake, drinking amount, urine amount, stool wet weight and assay of spontaneous activity (P<0.05). When observed under a light microscope, the colon tissues of rats in the model group showed mucosal edema, congestion, inflammatory cell infiltration and ulceration. The degree of colon injury and IL-6, IL-8 and TNF-α levels were significantly increased (P<0.05) as compared to those in the normal control group. The changes mentioned above were improved by Shenlin Baizhu Powder (P<0.05).

CONCLUSION

The rat model of ulcerative colitis with syndrome of spleen deficiency and dampness stagnancy is successfully induced and has the characteristics of ulcerative colitis of humans both in pathological changes and in syndrome.

Gut microbiota and inflammation

Systemic and local inflammation in relation to the resident microbiota of the human gastro-intestinal (GI) tract and administration of probiotics are the main themes of the present review. The dominating taxa of the human GI tract and their potential for aggravating or suppressing inflammation are described. The review focuses on human trials with probiotics and does not include in vitro studies and animal experimental models. The applications of probiotics considered are systemic immune-modulation, the metabolic syndrome, liver injury, inflammatory bowel disease, colorectal cancer and radiation-induced enteritis. When the major genomic differences between different types of probiotics are taken into account, it is to be expected that the human body can respond differently to the different species and strains of probiotics. This fact is often neglected in discussions of the outcome of clinical trials with probiotics.

Antioxidant properties of probiotics and their protective effects in the pathogenesis of radiation-induced enteritis and colitis

Radiation therapy has become one of the most important treatment modalities for human malignancy, but certain immediate and delayed side-effects on the normal surrounding tissues limit the amount of effective radiation that can be administered. After exposure of the abdominal region to ionizing radiation, nearly all patients experience transient symptoms of irradiation of the bowel. Acute-phase symptoms may persist for a short time, yet long-term complications can represent significant clinical conditions with high morbidity. Data from both experimental studies and clinical trials suggest the potential benefit for probiotics in radiation-induced enteritis and colitis. On the other hand, it is well evidenced that both useful and harmful effects of therapeutic applications of ionizing radiation upon living systems are ascribed to free-radical production. Therefore, the hypothesis that probiotics reinforce antioxidant defense systems of normal mucosal cells exposed to ionizing radiation may explain to an extent their beneficial action. The aim of this review is threefold: First, to make a short brief into the natural history of radiation injury to the intestinal tract. Second, to describe the primary interaction of ionizing radiation at the cellular level and demonstrate the participation of free radicals in the mechanisms of injury and, third, to try a more profound investigation into the antioxidant abilities of probiotics and prebiotics based on the available experimental and clinical data.

Mechanisms of transcriptional modulation of the human anion exchanger SLC26A3 gene expression by IFN-{gamma}

Two members of the SLC26 gene family, SLC26A3 or DRA (downregulated in adenoma) and SLC26A6 (putative anion transporter 1, PAT1), are known to play a major role in apical Cl(-)/OH(-) (HCO(3)(-)) exchange process in the human intestine. We have previously shown the inhibitory effects of IFN-gamma (30 ng/ml, 24 h) on both SLC26A3 and A6 expression and promoter activity. We also demonstrated that the effects of IFN-gamma on SLC26A6 gene expression were mediated via IRF-1 transcription factor. However, the molecular mechanisms underlying the transcriptional modulation of SLC26A3 gene expression by IFN-gamma in the intestine are not known. The present studies were, therefore, designed to elucidate the signaling mechanisms and transcription factor(s) involved in mediating the inhibitory effects of IFN-gamma on DRA promoter (p--1183/+114) activity. Deletion analysis indicated that the IFN-gamma response element is located within the -1183 to -790 region, and sequence analysis of this region revealed the presence of potential gamma-activated site (GAS), a binding site (-933/-925 bp) for signal transducer and activator of transcription factor 1 (STAT1). Mutations in the potential GAS element abrogated the inhibitory effects of IFN-gamma. These studies provide evidence for the involvement of STAT1 in the inhibition of SLC26A3 gene expression by IFN-gamma in the human intestine.

A murine model for the study of molecular pathogenesis of radiation proctitis

PURPOSE

To establish a novel mouse brachytherapy model with which to study the role of inflammation in the pathogenesis of radiation proctitis.

METHODS AND MATERIALS

The distal rectums of BALB/c and C57BL/6 mice were irradiated with three to five fractions of 5.5 to 8 Gy. Tissues were harvested and evaluated for histopathology, using the radiation injury score (RIS). Cytokine mRNA expression was assessed using real-time PCR.

RESULTS

Fifty percent of the mice treated with 22 Gy delivered in four fractions of 5.5 Gy died as a result of anorectal stenosis and distal bowel obstruction prior to the time of scheduled sacrifice, with a latency period of 4 to 10 weeks for the BALB/c and 3 to 4 weeks for the C57BL/6 mice. The RISs were 7, 12, and 8 at 2, 6, and 11 weeks, respectively, in the BALB/c mice and was 8.7 in the C57BL/6 mice on week 6. A 100- to 300-fold increase in interleukin-1beta (IL-1beta) (p = 0.04) and IL-6 mRNA (p = 0.07) and a 5- to 6-fold increase in transforming growth factor (TGF) and tumor necrosis factor-alpha mRNA expression levels (p < 0.001 and p = 0.01) were observed at 2 to 6 weeks after radiation. Cytokine mRNA tissue expression correlated positively with radiation dose (p < 0.0001). The RIS correlated well with IL-1beta and IL-6 mRNA levels in the BALB/c mice and with IL-1beta, IL-6, and TGF mRNA levels in C57BL/6 mice. Analysis of receiver operating characteristic curve showed that IL-1beta and IL-6 have the largest area under the curve and therefore are good markers of radiation proctitis (p < 0.001).

CONCLUSIONS

Radiation-induced proctitis was associated with a dose-dependent, characteristic proinflammatory cytokine response pattern in a novel mouse model suitable for interventional studies.

Effect of Wumeiwan on cytokines TNF-alpha, IL-6, IL-8, IL-10 and expression of NF-kappaBp65 in rats with ulcerative colitis

The effects of Wumeiwan (WMW) on TNF-alpha, IL-6, IL-8, IL-10 and NF-kappaBp65 in rats with ulcerative colitis (UC) were investigated, the curative effectiveness of WMW vs salicylazosulfapyridine (SASP) was compared, and the action mechanism was analyzed. Fifty-Six Sprague-Dawley (SD) rats were randomly divided into four groups (n=14 in each group, with equal ratio of male and female): normal control group, model group, SASP group, and WMW group. Except normal control group, the rat UC models in the remaining three groups were established using the method of 2.4-dinitrochlorobenzene (DNCB) immunization and acetic acid local enema. The rats in model group, SASP group, and WMW group were treated with distilled water, SASP, and WMW respectively. The changes in the symptoms and signs were observed, and levels of IL-6, IL-8, TNF-alpha, IL-10 and the expression of NF-kappaBp65 in the colonic tissues were statistically analyzed. The results showed that the levels of IL-6, IL-8, and TNF-alpha were significantly increased (P<0.01), while those of IL-10 significantly reduced (P<0.01) after establishment of rat UC models as compared with normal control group. The levels of IL-6, IL-8, and TNF-alpha were obviously lower, but the level of IL-10 was obviously higher in WMW and SASP groups than those in model group (P<0.05). The levels of IL-6, IL-8, and TNF-alpha were lower, while the level of IL-10 was higher in WMW group than in SASP group. NF-kappaBp65 was expressed negatively or weakly in normal colonic tissues. The positive expression rate of NF-kappaBp65 in WMW group and SASP group was obviously lower than in model group (P<0.01), and there was significant difference between WMW group and SASP group (P<0.05). It was concluded that rat UC model was established successfully. WMW could up-regulate the expression of IL-10, down-regulate the expression of TNF-alpha, IL-6, IL-8, and inhibit the NF-kappaBp65 activity to adjust immune function, indicating WMW had better curative effects on UC in rats.

Therapeutic effects of somatostatin on the intestinal inflammatory injury in rat model of ulcerative colitis

AIM: To study the therapeutic effects of somatostatin (octreotide) on 2, 4, 6-trinitrobenzene sulfonic acid induced ulcerative colitis (UC) in rats and to explore its possible mechanism.

METHODS: Twenty-eight female SD rats were randomized into normal control group, octreotide control group, model group and treatment groups (7 rats for each group). UC in model group and treatment group was induced by intrarectal administration of TNBS (100 mg/kg in 50% ethanol). Octreotide 50 µg/kg per day (octreotide control group and treatment group) or saline 1 mL per day (normal control group and model group) was administered intraperitoneally each day for 14 days. All animals were killed on day 15. The body weight loss of each rat, macroscopical and histological changes of the colon were observed. IL-6, IL-10, tumor necrosis factor (TNF-α) in colon supernate were tested by ELISA and the expression of nuclear factor (NF)-κB p65 in the colonic tissues was detected using Western blot.

RESULTS: Compared with the model group, somatostatin inhibited the body weight loss and occurrence of diarrhea as well as rectal bleeding in the rats, and significantly improved the macroscopic damage score and histological score in the treatment group. Compared with the normal group, colonic mucosal IL-6, TNF-α expression of model group rats were significantly increased (188.27 ± 11.65 ng/L vs 102.13 ± 7.12 ng/L, 121.51 ± 8.56 ng/L vs 87.39 ± 6.74 ng/L, both P < 0.01); IL-10 expression was significantly decreased (71.40 ± 8.28 ng/L vs 202.97 ± 12.26 ng/L, P < 0.01); Compared with the model group, mucosal IL-6, TNF-α expression of the treatment group rats colon were significantly lower (142.03 ± 12.68 ng/L, 90.87 ± 9.26 ng/L, both P < 0.01), IL-10 expression was significantly elevated (124.07 ± 10.05 ng/L, P < 0.01). For the model group, the colon tissue of NF-κB protein content was significantly higher than the treatment group (1059.60 ± 96.35 vs 471.23 ± 11.61, P < 0.01).

CONCLUSION: Somatostatin has noticeable therapeutic effects on TNBS-induced ulcerative colitis in rats. Suppressing NF-κB activation, decreasing the expression of proinflammatory cytokines and increasing the expression of anti-inflammatory cytokines may be the possible mechanism.

Characterization of the 5'-flanking region and regulation of expression of human anion exchanger SLC26A6

SLC26A6 (putative anion transporter 1, PAT1) has been shown to play an important role in mediating the luminal Cl(-)/OH(-)(HCO(3)(-)) exchange process in the intestine. Very little is known about the molecular mechanisms involved in the transcriptional regulation of intestinal SLC26A6 gene expression in the intestine. Current studies were, therefore, designed to clone and characterize the 5'-regulatory region of the human SLC26A6 gene and determine the mechanisms involved in its regulation. A 1,120 bp (p-964/+156) SLC26A6 promoter fragment cloned upstream to the luciferase reporter gene in pGL2-basic exhibited high promoter activity when transfected in Caco2 cells. Progressive deletions of the 5'-flanking region demonstrated that -214/-44 region of the promoter harbors cis-acting elements important for maximal SLC26A6 promoter activity. Since, diarrhea associated with inflammatory bowel diseases is attributed to increased secretion of pro-inflammatory cytokines, we examined the effects of IFNgamma (30 ng/ml, 24 h) on SLC26A6 function, expression and promoter activity. IFNgamma decreased both SLC26A6 mRNA and function and repressed SLC26A6 promoter activity. Deletion analysis indicated that IFNgamma response element is located between -414/-214 region and sequence analysis of this region revealed the presence of potential Interferon Stimulated Responsive Element (ISRE), a binding site (-318/-300 bp) for interferon regulatory factor-1 transcription factor (IRF-1). Mutations in the potential ISRE site abrogated the inhibitory effects of IFNgamma. These studies provided novel evidence for the involvement of IRF-1 in the regulation of SLC26A6 gene expression by IFNgamma in the human intestine.

Re-epithelialization of squamous epithelium for a radiation-induced rectal ulcer while giving an ecabet sodium enema

The present patient developed a severe rectal ulcer more than 1 month after having received external beam radiation therapy for prostate cancer. Surveillance endoscopy every 3 months demonstrated healing of this rectal ulcer using a novel therapy. He was given enemas with ecabet sodium, which provides physical protection and promotes healing by increasing prostaglandin E(2), and this process induced squamous metaplasia that halted the progression of the ulcer of radiation proctitis as a late-phase reaction. Intrapapillary capillary loops were visualized with magnified narrow band imaging at the healing ulcer site as seen via the esophagus and, moreover, demonstrated histologically.

Recent advances in the management of radiation colitis

Radiation colitis, an insidious, progressive disease of increasing frequency, develops 6 mo to 5 years after regional radiotherapy for malignancy, owing to the deleterious effects of the latter on the colon and the small intestine. When dealing with radiation colitis and its complications, the most conservative modality should be employed because the areas of intestinal injury do not tend to heal. Acute radiation colitis is mostly self-limited, and usually, only supportive management is required. Chronic radiation colitis, a poorly predictable progressive disease, is considered as a precancerous lesion; radiation-associated malignancy has a tendency to be diagnosed at an advanced stage and to bear a dismal prognosis. Therefore, management of chronic radiation colitis remains a major challenge owing to the progressive evolution of the disease, including development of fibrosis, endarteritis, edema, fragility, perforation, partial obstruction, and cancer. Patients are commonly managed conservatively. Surgical intervention is difficult to perform because of the extension of fibrosis and alterations in the gut and mesentery, and should be reserved for intestinal obstruction, perforation, fistulas, and severe bleeding. Owing to the difficulty in managing the complications of acute and chronic radiation colitis, particular attention should be focused onto the prevention strategies. Uncovering the fibrosis mechanisms and the molecular events underlying radiation bowel disease could lead to the introduction of new therapeutic and/or preventive approaches. A variety of novel, mostly experimental, agents have been used mainly as a prophylaxis, and improvements have been made in radiotherapy delivery, including techniques to reduce the amount of exposed intestine in the radiation field, as a critical strategy for prevention.

Effects of transplanted bone marrow mesenchymal stem cells on the irradiated intestine of mice

We investigated the potency of exogenous bone marrow mesenchymal stem cells (MSCs) to engraft into irradiated intestine, as well as these cells' effects on radiation-induced enteric injury. MSCs from beta-Gal-transgenic mice were transplanted into C57BL/6J recipient mice that received abdominal irradiation (13 Gy). At different time points, recipient intestines were examined for the engraftment of donor-derived cells by immunofluorescence analysis. Additionally, the expression status of chemokines induced by radiation injury was analyzed in the irradiated intestine. Next, MSCs were transduced with an adenoviral vector encoding a certain chemokine receptor gene in order to promote the engraftment rate via chemotaxis. The intestinal permeability and histomorphological alterations were measured to evaluate the therapeutic effect of MSC transplantation. The results demonstrated that infused MSCs possessed the potency to engraft into irradiated enteric mucosa, but the engraftment rate was too low to produce a therapeutic effect. The expression of stromal cell-derived factor-1 (SDF-1) was up-regulated in irradiated intestine. MSCs genetically modified by CXCR4 (the receptor for SDF-1) engrafted into irradiated intestine at a significantly elevated level and ameliorated the intestinal permeability and histopathological damage.