肠黏膜屏障与炎症性肠病

炎症性肠病（Innammatory bowel disease，IBD）是一组病因不明的慢性肠道炎症性疾病，主要包含两个独立的疾病，溃疡性结肠炎（Ulcerative colitis，UC）和克罗恩病（Crohn’s disease，CD）。近年研究发现，肠黏膜屏障功能异常在IBD发病机制中发挥重要作用。更好地了解正常及疾病状态下肠黏膜屏障的结构和功能可以为IBD的治疗提供新的思路。     

Qualitative and quantitative analyses of the bifidobacterial microbiota in the colonic mucosa of patients with colorectal cancer, diverticulitis and inflammatory bowel disease

AIM： To characterize the bifidobacterial microbiota of the colonic mucosa in patients with colon cancer, inflammatory bowel disease or diverticulitis.
METHODS： A sample of the distal colonic mucosa was taken during surgery from a total of 34 patients, twenty-one with diagnosed colorectal cancer, nine with diverticulitis and four with inflammatory bowel disease, requiring surgery for their condition. Bacterial DNA was extracted from the resected mucosal samples and bifidobacterial mucosa-associated microbiota was qualitatively and quantitatively determined by means of qualitative and quantitative PCR.
RESULTS： Bifidobacteria were found in 100% of the samples from patients with diverticulitis or IBD and a 76% of those suffering colon cancer. The species B. Iongum and B. bifidum were the most widely found, followed by B. animalis, B. catenulatum and B. adolescentis. B. breve, B. dentium and B. angulatum were not detected in any sample. A significantly higher occurrence of B. Iongum was observed in patients with diverticulitis than in those with colon cancer or IBD （100%, 62% and 75%, respectively, P 〈 0.05）. Similar results were obtained for B, animalis （56%, 0% and 25%, P 〈 0.05）, while B. adolescentis was only found in the mucosa from patients with colon cancer （5 out of 21, 24%）. At the quantitative level, patients with colon cancer or IBD showed lower counts of total Bifidobacterium （4.94 and 5.91 vs 6.96 log Cells/sample, respectively, P 〈 0.05） and of the species B. longum （4.05 and 4.79 vs 6.76, P 〈 0.05） than those with diverticulitis.
CONCLUSION： Aberrancies in mucosa associated microbiota are present in different intestinal diseases. This may indicate a role of the microbiota in the pathogenesis of these diseases.     

Toll-like receptors in inflammatory bowel disease-stepping into uncharted territory

Ulcerative colitis and Crohn＇s disease are chronic relapsing-remitting inflammatory processes of the intestinal tract. The etiology of these diseases is currently unknown. However, inflammation is hypothesized to result from inappropriate activation of mucosal immunity by luminal antigens in genetically susceptible individuals. Toll-like receptors （TLRs） are a family of transmembrane proteins that act as microbial pattern recognition receptors. They are crucial initiators of innate immune responses. The role of TLRs in the pathogenesis of inflammatory bowel disease （IBD） has not been fully elucidated. In this review, we aim to analyze the available data connecting individual TLRs to intestinal inflammation and IBD.     

IL-27在炎症性肠病炎症肠黏膜中的表达及意义

目的:检测克罗恩病(CD)和溃疡性结肠炎(UC)肠黏膜组织中IL-27 p28 mRNATL其蛋白、IL-27受体mRNA的表达,探讨其在CD和UC中的发病意义.方法:应用反转录-聚合酶链反应(RT-PCR)和蛋白质免疫印迹(Western blot)方法检测炎症性肠病患者炎症肠黏膜组织中IL-27 p28基因及蛋白、IL-27受体基因的表达,并与健康者作对照.结果:IL-27 p28 mRNA在CD患者中的阳性率和灰度分析表达较UC患者明显增高(X2=6.64,P<0.05;t=11.01,P<0.01),IL-27受体阳性率和灰度分析在CD患者较UC患者和健康对照者明显增高(阳性率:X2=10.91,P<0.016,X2=18.84,P<0.016).IL-27蛋白阳性率和灰度分析在CD患者中表达明显高于UC患者(X2=5.24,P<0.05;t=3.37,P<0.05),并且IL-27mRNA的表达与蛋白质表达密切相关.结论:IL-27 p28及其受体的上调,可能有助于CD患者炎症发展过程.     

微生态失衡与炎症性肠病

炎症性肠病(IBD)包括克罗恩病(CD)和溃疡性结肠炎(UC),其病因和发病机制目前尚不清楚。研究发现,肠道微生态失衡即肠道致病菌和益生菌之间的平衡失调,在IBD的发生和发展中发挥重要作用。此文就微生态失衡在IBD发病中的作用作一综述。     

Relationship between methylation and colonic inflammation in inflammatory bowel disease

AIM:To investigate the relationship between the methylation status in the SLIT2 and TGFB2 promoters and colonic inflammation in inflammatory bowel disease patients.METHODS:We evaluated the methylation status of 2genes(SLIT2 and TGFB2)in 226 biopsies taken from62 colonoscopies of 38 patients(29 ulcerative colitis and 9 Crohn’s colitis)using methylation-specific melting curve analysis.The relationships between methylation status and clinical,biological,endoscopic and histological activities were evaluated.Twenty-three of the 38patients had a second colonoscopy and were included in a longitudinal analysis.Numerical results were given as the means±SD of the sample and range,except when specified.Student t analysis,U Mann Whitney and ANOVA factor were used to compare the means.Qualitative results were based on theχ2 test.RESULTS:SLIT2 methylation was more frequent in samples with endoscopic activity than with endoscopic remission(55%vs 18%,P<0.001).SLIT2 methylation was also higher in samples with acute inflammation(56.5%)than in samples with chronic(24%)or absent inflammation(15%)(P<0.001).For TGFB2methylation,the correlation was only significant with endoscopic activity.Methylation was higher in the distal colon for both genes(P<0.001 for SLIT2 and P=0.022for TGFB2).In the multivariate analysis,only inflammation status(and not disease duration or extension)was independently associated with SLIT2 methylation[OR=6.6(95%CI:1.65-27.36),P=0.009].In the longitudinal analysis,the maintenance of endoscopic remission was protective for methylation.CONCLUSION:Endoscopic and histological inflammation are predictive for SLIT2 methylation.     

Fatigue in children and adolescents with inflammatory bowel disease

AIM To identify factors other than active disease and anemia that contribute to fatigue in pediatric inflammatory bowel disease(IBD).METHODS We performed an electronic search in Medline and EMBASE from their inception to May 2017 using the search term "fatigue" or the related keywords "physical impairment" and "inflammatory bowel disease" with the filter "child"(age 0-18 years). Cross-sectional and case-control studies were included. We restricted our search to studies published in English. We used the PRISMA checklist and flow diagram. Duplicate articles were manually deleted in End Note. To identify further relevant studies, we checked the reference lists of the selected articles.RESULTS We identified 149 papers, of which 19 were retrieved for full text review. Eleven studies were subsequently excluded because fatigue was not evaluated as an outcome measure. Eight papers focused on the desired topic and were discussed in the final analysis. A lack of uniformity of outcome measures made the pooling of data impossible. In all but one study, questionnaires were used to evaluate fatigue. In the remaining study, an accelerometer was used to measure daily activities, sleeping time and their relationships with fatigue in a more quantifiable manner. Adolescents with IBD are significantly more fatigued than healthy controls. In addition to active disease, increased anxiety or depression and disturbed family relationships were frequently reported predictors of fatigue. Quantitative measurement of physical activity in patients with Crohn's disease showed a reduction in the number of steps per day, and patients with ulcerative colitis had a shorter duration of physical activity during the day.CONCLUSION Fatigue in pediatric IBD is related to a combination of biological, functional and behavioral factors, which should all be taken into account when managing fatigue.     

Innate immunity in inflammatory bowel disease

The human intestinal tract is home to an enormous bacterial flora. The host defense against microorganisms can be divided into innate and adaptive immunity. The former is the most immediate line of response to immunologic challenges presented by bacteria, viruses, and fungi. The mucosal immune system has evolved to balance the need to respond to pathogens while co-existing with commensal bacteria and food antigens. In inflammatory bowel disease （IBD）, this hyporesponsiveness or tolerance breaks down and inflammation supervenes driven by the intestinal microbial flora. Bacteria contain compounds and are recognized by a variety of receptors, including Toll-like receptors （TLRs） and NODs （a family of intracellular bacterial sensors） and are potent stimuli of innate immune responses. Several mutations in these receptors have been associated with development of IBD.     

Analysis of TLR4 and TLR2 polymorphisms in inflammatory bowel disease in a Guangxi Zhuang population

AIM: To study the polymorphisms of toll-like receptor 4 (TLR4) gene Asp299Gly, Thr399Ile and TLR2 gene Arg753Gln, Arg677Trp and susceptibility to inflammatory bowel disease (IBD) in the Zhuang population from Guangxi, China.METHODS: A case-control study was performed from February 2007 to October 2011 which included 146 Zhuang patients with IBD in the experimental group and 164 healthy Zhuang subjects who acted as the control group. All patients and healthy subjects were from the Guangxi Zhuang Autonomous Region of China. Genomic DNA was extracted from intestinal tissue by the phenol chloroform method. TLR4 gene Asp299Gly, Thr399Ile and TLR2 gene Arg753Gln, Arg677Trp were amplified by polymerase chain reaction (PCR), and then detected by PCR-restriction fragment length polymorphism (RFLP).RESULTS: The TLR4 gene Asp299Gly was digested using Nco I restriction enzyme, and a single band of 249 bp was observed which showed that it was a wild type (AA). The TLR4 gene Thr399Ile was digested using Hinf Irestriction enzyme and only the wild type (CC) was detected. In addition, the TLR2 gene Arg677Trp was digested using Aci I restriction enzyme and only the wild type (CC) was detected. The TLR2 gene Arg753Gln was digested using Pst I restriction enzyme. Only the wild type (GG) as a single band of 254 bp was observed during RFLP. Overall, no heterozygous or homozygous single nucleotide polymorphism mutations were found in patients with Crohn’s disease and ulcerative colitis both in the TLR4 gene Asp299Gly, Thr399Ile and the TLR2 gene Arg677Trp, Arg753Gln in the Zhuang population from the Guangxi Zhuang Autonomous Region of China.CONCLUSION: The TLR4 gene Asp299Gly, Thr399Ile and TLR2 gene Arg753Gln, Arg677Trp polymorphisms may not be associated with IBD in the Zhuang population from the Guangxi Zhuang Autonomous Region of China.     

Intestinal barrier in inflammatory bowel disease

A complex mucosal barrier protects as the first line of defense the surface of the healthy intestinal tract from adhesion and invasion by luminal microorganisms.In this review,we provide an overview about the major components of this protective system as for example an intact epithelium,the synthesis of various antimicrobial peptides(AMPs)and the formation of the mucus layer.We highlight the crucial importance of their correct functioning for the maintenance of a proper intestinal function and the prevention of dysbiosis and disease.Barrier disturbances including a defective production of AMPs,alterations in thickness or composition of the intestinal mucus layer,alterations of pattern-recognition receptors,defects in the process of autophagy as well as unresolved endoplasmic reticulum stress result in an inadequate host protection and are thought to play a crucial role in the pathogenesis of the inflammatory bowel diseases Crohn’s disease and ulcerative colitis.     

Sclerosing cholangitis in children with inflammatory bowel disease

Background: Primary sclerosing cholangitis (PSC) with inflammatory bowel disease (IBD) has been rarely reported in children.
Aim: To describe the clinical presentation, sequential liver function test abnormalities, radiological bile duct anomalies and liver histology in four children with PSC and IBD.
Methods: Over a period of 18 years, four of 130 patients with IBD developed abnormal liver function tests. Three of the four patients had ulcerative colitis and the other Crohn's disease. All four patients had baseline and follow-up liver function tests, percutaneous transhepatic cholangiography and a needle biopsy of the liver.
Results: The four patients at presentation had minimal symptoms or signs of liver disease. All had elevation of serum transaminases, gamma glutamyl transferase and/or alkaline phosphatase. Three had the typical onion skin fibrosis of bile ducts. Percutaneous transhepatic cholangiography demonstrated irregularity and beading of the hepatic and common bile ducts in three patients. The other with normal cholangiography had fibrosing cholangitis on liver biopsy and was considered to have small duct disease.
Conclusions: We conclude that yearly biochemical assessment of liver function should be performed on all children with IBD, and if abnormal should raise the suspicion of PSC. The latter diagnosis can be confirmed by liver biopsy and cholangiography.     

Intestinal fibrosis in inflammatory bowel disease — Current knowledge and future perspectives

Background and aimsIntestinal fibrosis is a common complication of IBD that can become seriously symptomatic and may require surgical intervention if stricture formation ensues. This review discusses existing and developing knowledge of intestinal fibrosis and its implications for therapy.MethodsReview of the literature, personal communications, unpublished observations.ResultsKnown mechanisms of intestinal fibrosis include fibroblast proliferation and migration, activation of stellate cells, and extraintestinal fibroblast recruitment. However, novel mechanisms are being uncovered, including epithelial-to-mesenchymal transition, endothelial-to-mesenchymal transition, pericyte differentiation, and fibrocyte recruitment. Most of the traditional and novel mechanisms underlying intestinal fibrosis are associated to the presence of chronic inflammation, but is also possible that fibrosis develops independently of persistent immune activation in the gut. At the moment, the development of preventive, non-interventional, and more effective management of intestinal fibrosis is hampered by the lack of a greater knowledge of its basic pathophysiology and predisposing factors.ConclusionsIt is reasonable to expect that therapy of IBD-associated fibrosis will radically improve once the underlying mechanisms are better understood, and therapeutic modalities will emerge that prevent or reverse this complication of IBD.     

肠道平滑肌动力与炎症性肠病研究进展

肠道平滑肌动力改变与炎症性肠病(IBD)的发病关系得到医学界的重视,并逐渐成为IBD发病机制研究的热点.肠道运动的异常和神经递质的失衡在IBD的发生和进展过程中起了重要作用;白细胞介素能在一定程度上反映肠道运动功能变化.因此,恢复神经递质的失衡并重建肠道动力平衡的策略在IBD治疗过程中有良好的应用前景.     

Improved diagnostic accuracy of inflammatory bowel disease: a clinicopathological collaborative approach

Abstract. Although colonic biopsies have become a major source of information to the clinician investigating cases of inflammatory bowel diseases (IBD), there are still some difficulties in making definitive diagnoses. This article looks into these challenges and possible ways of dealing with them. We strongly recommend supplying the pathologist with full clinical, radiological and endoscopic information with the request form. The pathologist may then issue a preliminary working report, while the final report should be reached at the much needed regular clinicopathological conference.     

益生菌对炎症性肠病的治疗作用和机制

炎症性肠病包括溃疡性结肠炎和克罗恩病.炎症性肠病患者肠道内存在茵群失调,若给患者补充正常细菌即益生菌,使肠道内菌群失调得到纠正,可使病情缓解.益生菌能改变肠道菌群比例、转化某些肠内物质、提高肠上皮的屏障功能、防止肠细菌易位以及通过调节细胞因子减轻炎症.本文对益生菌以上作用及机制作一综述.     

Antibiotics and probiotics in treatment of inflammatory bowel disease

Many experimental and clinical observations suggest that intestinal microflora plays a potential role in the pathogenesis of inflammatory bowel disease (IBD). Manipulation of the luminal content using antibiotics or probiotics represents a potentially effective therapeutic option. The available studies do not support the use of antibiotics in ulcerative colitis (UC). Antibiotics are effective in treating septic complications of Crohn's disease (CD) but their use as a primary therapy is more controversial, although this approach is frequently and successfully adopted in clinical practice. There is evidence that probiotic therapy may be effective in the prevention and treatment of mild to moderate UC. In contrast, a lack of successful study data at present precludes the widespread use of probiotics in the treatment of CD. Both antibiotics and probiotics appear to play a beneficial role in the treatment and prevention of pouchitis and further trials are warranted to fully quantify their clinical efficacy.     

Serum vitamin D and colonic vitamin D receptor in inflammatory bowel disease

AIM: To determine serum vitamin D levels and colonic vitamin D receptor(VDR) expression in inflammatory bowel disease(IBD) and non-IBD patients and correlate these with histopathology.METHODS: Puerto Rican IBD(n = 10) and non-IBD(n = 10) patients ≥ 21 years old scheduled for colonoscopy were recruited. Each patient completed a questionnaire and provided a serum sample and a colonic biopsy of normal-appearing mucosa. For IBD patients, an additional biopsy was collected from visually diseased mucosa. Serum vitamin D levels were measured by ultra-performance liquid chromatography and mass spectrometry. Hematoxylin and eosin stained tissue sections from colonic biopsies were classified histologically as normal or colitis(active/inactive), and scored for the degree of inflammation present(0-3, inactive/absent to severe). Tissue sections from colonic biopsies were also stained by immunohistochemistry for VDR, for which representative diagnostic areas were photographed and scored for staining intensity using a 4-point scale.RESULTS: The IBD cohort was significantly younger(40.40 ± 5.27, P 0.05) than the non-IBD cohort(56.70 ± 1.64) with a higher prevalence of vitamin D deficiency(40% vs 20%, respectively) and insufficiency(70% vs 50%, respectively). Histologic inflammation was significantly higher in visually diseased mucosa from IBD patients(1.95 ± 0.25) than in normalappearing mucosa from control patients(0.25 ± 0.08, P 0.01) and from IBD patients(0.65 ± 0.36, P 0.05) and correlated inversely with VDR expression in visually diseased colonic tissue from IBD patients(r =-0.44, P 0.05) and from IBD patients with Crohn's disease(r =-0.69, P 0.05), but not in normal-appearing colonic tissue from control patients or IBD patients. Control and IBD patient serum vitamin D levels correlated positively with VDR expression in normal colon from control and IBD patients(r = 0.38, P 0.05) and with patient age(r = 0.54, P 0.01). CONCLUSION: Levels of serum vitamin D correlate positively with colonic VDR expression in visually normal mucosa whereas inflammation correlates negatively with colonic VDR expression in visually diseased mucosa in Puerto Rican patients.     

趋化因子及其受体与炎症性肠病

炎症性肠病(IBD)包括溃疡性结肠炎(UC)和克罗恩病(CD),是一类慢性反复发作的肠道非特异性炎症性疾病,其病因和发病机制尚未完全阐明,免疫反应异常是其重要特点.趋化因子是炎症反应中白细胞募集的最重要的调节因子,很多趋化因子参与IBD的发病.此文就近年来趋化因子及其受体与炎症性肠病的研究进展作一综述.