The Citrobacter rodentium Mouse Model: Studying Pathogen and Host Contributions to Infectious Colitis

This protocol outlines the steps required to produce a robust model of infectious disease and colitis, as well as the methods used to characterize Citrobacter rodentium infection in mice. C. rodentium is a gram negative, murine specific bacterial pathogen that is closely related to the clinically important human pathogens enteropathogenic E. coli and enterohemorrhagic E. coli. Upon infection with C. rodentium, immunocompetent mice suffer from modest and transient weight loss and diarrhea. Histologically, intestinal crypt elongation, immune cell infiltration, and goblet cell depletion are observed. Clearance of infection is achieved after 3 to 4 weeks. Measurement of intestinal epithelial barrier integrity, bacterial load, and histological damage at different time points after infection, allow the characterization of mouse strains susceptible to infection.The virulence mechanisms by which bacterial pathogens colonize the intestinal tract of their hosts, as well as specific host responses that defend against such infections are poorly understood. Therefore the C. rodentium model of enteric bacterial infection serves as a valuable tool to aid in our understanding of these processes. Enteric bacteria have also been linked to Inflammatory Bowel Diseases (IBDs). It has been hypothesized that the maladaptive chronic inflammatory responses seen in IBD patients develop in genetically susceptible individuals following abnormal exposure of the intestinal mucosal immune system to enteric bacteria. Therefore, the study of models of infectious colitis offers significant potential for defining potentially pathogenic host responses to enteric bacteria. C. rodentium induced colitis is one such rare model that allows for the analysis of host responses to enteric bacteria, furthering our understanding of potential mechanisms of IBD pathogenesis; essential in the development of novel preventative and therapeutic treatments.     

Association of the macrophage migration inhibitory factor gene − 173G/C polymorphism with inflammatory bowel disease: A meta-analysis of 4296 subjects

A variety of epidemiologic studies have focused on the association between macrophage migration inhibitory factor (MIF) gene − 173G/C polymorphism and inflammatory bowel disease (IBD). However, results in different studies have been inconsistent. In order to derive a more precise estimation of the associations, we performed this meta-analysis and systematic searches of electronic databases PubMed and Web of Science (up to April 30, 2013). Based on our search criteria, a total of seven eligible studies concerning the MIF − 173G/C polymorphism and IBD risk were included in the final meta-analysis, comprising 2162 IBD cases and 2134 controls. Significant association was found between MIF − 173G/C polymorphism and the risk of IBD when all studies were pooled into the meta-analysis (for C allele vs. G allele: OR = 1.25, 95% CI = 1.12–1.41, p = 0.000; for C/C vs. G/G: OR = 1.71, 95% CI = 1.23–2.39, p = 0.002; for C/C + G/C vs. G/G: OR = 1.24, 95% CI = 1.09–1.42, p = 0.002; for C/C vs. G/C + G/G: OR = 1.67, 95% CI = 1.20–2.33, p = 0.002). Heterogeneity and publication bias did not exist in the overall comparisons. The present meta-analysis suggests an association between the MIF − 173G/C polymorphism and IBD risk. However, due to few studies and the selection bias existed in some studies, the results should be interpreted with caution.     

Proteins Released from Myofibrils by CASF (Ca2+-activated sarcoplasmic factor) and Trypsin

The nature of the soluble proteins and peptides released from myofibrils by treatment with CASF (Ca²⁺-activated sarcoplasmic factor) was investigated by using Polyacrylamide gel electrophoresis in both a nondenaturing and a denaturing (sodium dodecyl sulfate=SDS) solvent and by using gel permeation chromatography on Sepharose 6B. Both CASF and trypsin treatment cause removal of Z-disks before causing other ultrastructurally detectable degradation of myofibrils. CASF treatment of myofibrils releases a protein that is identical to α-actinin, one of the known components of the Z-disk, on the basis of mobility in Polyacrylamide gel electrophoresis in a nondenaturing solvent and in SDS and on the basis of elution from gel permeation columns. Trypsin treatment of myofibrils releases a number of smaller molecular weight products that cannot be identified with any of the known myofibrillar proteins. Hence, CASF seems to remove Z-disks from myofibrils by means of a very specific proteolytic activity that releases α-actinin without extensively degrading it. Trypsin, on the other hand, probably seems to remove Z-disks by degrading α-actinin to peptides.     

粪便乳铁蛋白评价溃疡性结肠炎活动性的临床价值

目的:探讨粪便乳铁蛋白作为溃疡性结肠炎活动性标志物的可能性。方法:选取溃疡性结肠炎患者42例,对照组炎症性肠病患者20例,采用酶联免疫吸附试验法测定粪便乳铁蛋白的含量,同时测定实验室指标白细胞计数、红细胞沉降率(ESR)、C反应蛋白(CPR)的水平。结果:1)溃疡性结肠炎组活动期粪便乳铁蛋白的含量显著高于缓解期和对照组,且活动期组轻、中、重度三级之间差异有统计学意义;粪便乳铁蛋白的含量随着内镜的分级程度的增高而增高,但与溃疡性结肠炎内镜分级之间相关性不明显r=0.4199(P=0.0517)。2)粪便乳铁蛋白对判断溃疡性结肠炎的活动性的特异性和敏感性显著高于外周血白细胞计数、C反应蛋白、红细胞沉降率。结论:粪便乳铁蛋白对溃疡性结肠炎活动性的判定价值显著高于白细胞计数、C反应蛋白、红细胞沉降率,但是否可以作为理想的替代肠镜的炎症性标志物还有待进一步的大样本研究。     

Calcium Signaling Controls Pathogenic Th17 Cell-Mediated Inflammation by Regulating Mitochondrial Function

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Construction of a Model Culture System of Human Colonic Microbiota to Detect Decreased Lachnospiraceae Abundance and Butyrogenesis in the Feces of Ulcerative Colitis Patients

Compositional alteration of the gut microbiota is associated with ulcerative colitis (UC). Here, a model culture system is established for the in vitro human colonic microbiota of UC, which will be helpful for determining medical interventions. 16S ribosomal RNA sequencing confirms that UC models are successfully developed from fecal inoculum and retain the bacterial species biodiversity of UC feces. The UC models closely reproduce the microbial components and successfully preserve distinct clusters from the healthy subjects (HS), as observed in the feces. The relative abundance of bacteria belonging to the family Lachnospiraceae significantly decreases in the UC models compared to that in HS, as observed in the feces. The system detects significantly lower butyrogenesis in the UC models than that in HS, correlating with the decreased abundance of Lachnospiraceae. Interestingly, the relative abundance of Lachnospiraceae does not correlate with disease activity (defined as partial Mayo score), suggesting that Lachnospiraceae persists in UC patients at a decreased level, irrespective of the alteration in disease activity. Moreover, the system shows that administration of Clostridium butyricum MIYAIRI restores butyrogenesis in the UC model. Hence, the model detects deregulation in the intestinal environment in UC patients and may be useful for simulating the effect of probiotics.     

Fasting-Mimicking Diet Modulates Microbiota and Promotes Intestinal Regeneration to Reduce Inflammatory Bowel Disease Pathology

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Mulberry juice freeze-dried powder attenuates the disease severity by the maintaining of colon mucosa in mice with DSS-induced acute colitis

This study aimed to evaluate the microbial compositions and gene expression related to inflammation in dextran sodium sulfate (DSS)-induced acute colitis and the effect of mulberry supplementation. Male BALB/c mice received a diet supplemented with mulberry juice freeze-dried powder (MFP) or not for 3 weeks. After 3 weeks, the mice received water containing 5% (w/v) DSS or not for 1 week. The disease activity index score in mice fed MFP was significantly decreased. A significant decrease in Bifidobacterium spp. and the Clostridium perfringens subgroup was observed in mice not fed MFP. The number of goblet cell and NLRP6 expression were observed in mice fed a diet supplemented with MFP compared with mice not fed MFP. These results may indicate that mulberry mitigates DSS-induced acute colitis by a changing the gut microbial flora and by improving mucosal conditions.     

Effects of alpha lipoic acid and its derivative “andrographolid-lipoic acid-1” on ulcerative colitis: A systematic review with meta-analysis of animal studies

We aimed to review and meta-analyze the inflammatory and oxidative factors following alpha lipoic acid (ALA) and its derivative “andrographolid-lipoic acid-1” (AL-1) in ulcerative colitis (UC). ALA plays an important role in scavenging intracellular radicals and inflammatory elements. AL-1 is found in herbal medicines with potent anti-inflammatory properties. Data were collected from the Google Scholar, PubMed, Scopus, Evidence-based medicine/clinical trials, and Cochrane library database until 2017, which finally resulted in 22 animal studies (70 rats and 162 mice). The beneficial effects of ALA or AL-1 on the most important parameters of UC were reviewed; also, studies were considered separately in mice and rats. Administration of ALA and AL-1 significantly reduced the tumor necrosis factor-α level compared with the controls, while data were not noteworthy in the meta-analysis (mean differences = −18.57 [95% CI = −42.65 to 5.51], P = 0.13). In spite of insignificant decrease in meta-analysis outcomes (differences = 6.92 [95% CI = −39.33 to 53.16], P = 0.77), a significant reduction in myeloperoxidase activity was shown following ALA or AL-1 treatment compared with the controls. Despite significant differences in each study, we had to exclude some studies to homogenize data for meta-analyzing as they showed insignificant results. Interleukin 6, cyclooxygenase-2, glutathione, malondialdehyde, superoxide dismutase, histopathological score, macroscopic and microscopic scores, disease activity index, body weight change, and colon length were also reviewed. Most studies have emphasized on significant positive effects of ALA and AL-1. Comprehensive clinical trials are obligatory to determine the precious position of ALA or AL-1 in the management of UC.