Unraveling the ties between irritable bowel syndrome and intestinal microbiota

Irritable bowel syndrome(IBS)is the most prevalent functional gastrointestinal disorder.It is a multifactoria disorder.Intestinal microbiota may cause the pathogenesis of IBS by contributing to abnormal gastrointestina motility,low-grade inflammation,visceral hypersensitivity,communication in the gut-brain axis,and so on.Previous attempts to identify the intestinal microbiota composition in IBS patients have yielded inconsistent and occasionally contradictory results.This inconsistency may be due to the differences in the molecular techniques employed,the sample collection and handling methods,use of single samples that are not linked to fluctuating symptoms,or other factors such as patients diets and phenotypic characterizations.Despite these difficulties,previous studies found that the intestina microbiota in some IBS patients was completely different from that in healthy controls,and there does appear to be a consistent theme of Firmicutes enrichment and reduced abundance of Bacteroides.Based on the differences in intestinal microbiota composition,many studies have addressed the roles of microbiotatargeted treatments,such as antibiotics and probiotics,in alleviating certain symptoms of IBS.This review summarizes the current knowledge of the associations between intestinal microbiota and IBS as well as the possible modes of action of intestinal microbiota in the pathogenesis of IBS.Improving the current level of understanding of host-microbiota interactions in IBS is important not only for determining the role of intestinal microbiota in IBS pathogenesis but also for therapeutic modulation of the microbiota.     

Lower Bifidobacteria counts in both duodenal mucosa-associated and fecal microbiota in irritable bowel syndrome patients

AIM： To determine the composition of both fecal and duodenal mucosa-associated microbiota in irritable bowel syndrome （IBS） patients and healthy subjects using molecular-based techniques.
METHODS： Fecal and duodenal mucosa brush samples were obtained from 41 IBS patients and 26 healthy subjects. Fecal samples were analyzed for the composition of the total microbiota using fluorescent in situ hybridization （FISH） and both fecal and duodenal brush samples were analyzed for the composition of bifidobacteria using real-time polymerase chain reaction.
RESULTS： The FISH analysis of fecal samples revealed a 2-fold decrease in the level of bifidobacteria （4.2 ± 1.3 vs 8.3 ± 1.9, P 〈 0.01） in IBS patients compared to healthy subjects, whereas no major differences in other bacterial groups were observed. At the species level, Bifidobacterium catenulatum levels were significantly lower （6 ± 0.6 vs 19 ± 2.5, P 〈 0.001） in the IBS patients in both fecal and duodenal brush samples than in healthy subjects.
CONCLUSION： Decreased bifidobacteria levels in both fecal and duodenal brush samples of IBS patients compared to healthy subjects indicate a role for microbiotic composition in IBS pathophysiology.     

Altered molecular signature of intestinal microbiota in irritable bowel syndrome patients compared with healthy controls: A systematic review and meta-analysis

BackgroundMany studies have reported significant changes in intestinal microbiota in irritable bowel syndrome (IBS) patients based on quantitative real-time PCR analysis.AimsWe aimed to review the alterations in intestinal microbiota.MethodsAn online search up to June 9, 2016, was conducted. This systematic review and meta-analysis included differential expression of intestinal microbiota in patients with IBS versus healthy controls (HCs) and subgroup analysis. We assessed the quality of the included studies using an original assessment tool.ResultsA total of 13 articles involving 360 IBS patients and 268 healthy controls were included. The quality assessment scores for these articles ranged from 5 to 8. Significant differences in expression in IBS patients were observed for Lactobacillus (SMD = −0.85, P < 0.001, I² = 28%), Bifidobacterium (SMD = −1.17, P < 0.001, I² = 79.3%), and Faecalibacterium prausnitzii (SMD = −1.05, P < 0.001, I² = 0.0%) but not Bacteroides-Prevotella group, Escherichia coli or other genera or species. Subgroup analysis showed that diarrhea-predominant IBS patients had significantly different expression of Lactobacillus (SMD = −1.81, P < 0.001) and Bifidobacterium (SMD = −1.45, P < 0.001).ConclusionDown-regulation of bacterial colonization including Lactobacillus, Bifidobacterium and F. prausnitzii was observed in IBS patients, particularly in diarrhea-predominant IBS (IBS-D). Microbiota changes participate in the pathogenesis of IBS and may underlie the efficacy of probiotic supplements.     

肠易激综合征与肠道微生态的研究现状分析

肠易激综合征(IBS)发病机制复杂,目前没有统一的理论能解释IBS的发病,也没有单一的药物能缓解IBS的所有症状。此文就肠易激综合征与肠道微生态研究现状作一综述。     

小肠细菌过度生长和肠易激综合征关系的探讨

目的　探讨小肠细菌过度生长与肠易激综合征发病中的关系。方法　用乳果糖氢呼气试验测定 49例腹泻及便秘型肠易激综合征病人口 -回盲瓣通过时间 ,并了解其阳性发生率 ;对其中 10例阳性者给普瑞博思治疗1周 ,进行治疗前后比较。结果　在肠易激综合征病人中腹泻及便秘型口 -回盲瓣通过时间较对照组延长 (P <0 0 5 ) ,阳性发生率无差别 (P >0 0 5 ) ,治疗后口 -回盲瓣通过时间改善明显 (P <0 0 5 ) ,症状改善。结论　小肠功能紊乱可导致小肠细菌过度生长 ,并可能是肠易激综合征发病因素之一。     

肠道感染和肠道菌群与肠易激综合征

肠易激综合征(IBS)是一种常见的胃肠功能性疾病。近年来,肠道感染、肠道菌群与IBS关系的研究已成为热点。此文探讨IBS与肠道感染、肠道菌群的关系以及微生态制剂治疗IBS的效果。     

肠易激综合征与肠道细菌关系的研究进展

肠易激综合征(irritable bowel syndrome,IBS) 是一种复杂的多因素功能性疾病,其病因和发病机制尚未明确.肠道共生菌与宿主和平共处,互惠互利,这种关系破坏直接或间接参与宿主多种疾病的发生与发展.近年来,随着微生态学的发展,肠道菌群与IBS 发病的关系日益受到关注.大量研究显示,肠道细菌与IBS ...     

Association of symptoms with gastrointestinal microbiota in irritable bowel syndrome

AIM:To investigate the correlations between selfreported symptoms of irritable bowel syndrome(IBS) and the gastrointestinal(GI) microbiota composition.METHODS:Fecal samples were collected from a total of 44 subjects diagnosed with IBS.Their symptoms were monitored with a validated inflammatory bowel disease questionnaire adjusted for IBS patients.Thirteen quantitative real-time polymerase chain reaction assays were applied to evaluate the GI microbiota composition.Eubacteria and GI bacterial genera(Bifidobacterium,Lactobacillus and Veillonella),groups(Clostridium coccoides/Eubacterium rectale,Desulfovibrio desulfuricans) and distinct bacterial phylotypes [closest 16S rDNA sequence resemblance to species Bifidobacterium catenulatum,Clostridium cocleatum,Collinsella aerofaciens(C.aerofaciens),Coprococcus eutactus(C.eutactus),Ruminococcus torques and Streptococcus bovis ] with a suspected association with IBS were quantified.Correlations between quantities or presence/absence data of selected bacterial groups or phylotypes and various IBSrelated symptoms were investigated.RESULTS:Associations were observed between subjects’ self-reported symptoms and the presence or quantities of certain GI bacteria.A Ruminococcus torques(R.torques)-like(94% similarity in 16S rRNA gene sequence) phylotype was associated with severity of bowel symptoms.Furthermore,among IBS subjects with R.torques 94% detected,the amounts of C.cocleatum 88%,C.aerofaciens-like and C.eutactus 97% phylotypes were significantly reduced.Interesting observations were also made concerning the effect of a subject’s weight on GI microbiota with regard to C.aerofaciens like phylotype,Bifidobacterium spp.and Lactobacillus spp.CONCLUSION:Bacteria seemingly affecting the symptom scores are unlikely to be the underlying cause or cure of IBS,but they may serve as biomarkers of the condition.     

肠道微生态与肠易激综合征

微生物群与宿主、环境之间的相互作用、相互协调对于维持宿主正常的生理功能起着十分重要的作用,三者关系失衡则直接或间接参与了众多疾病的发生、发展。肠易激综合征(IBS)是一种复杂的多因素功能性疾病,流行病学研究表明IBS患者多存在肠道菌群失调,益生菌的治疗也取得部分疗效,通过对正常人和IBS患者肠道菌群的比较,从小肠细菌过度生长、感染、抗生素、应激、肠道酵解异常五个方面,将近年肠道微生态与IBS关系做一综述。     

Differences of microbiota in small bowel and faeces between irritable bowel syndrome patients and healthy subjects

Objective Several studies suggested that colonic microbiota have impacts on irritable bowel syndrome (IBS) patients. However, the knowledge about the association of small intestine (SI) microbiota with IBS is limited. We aimed to investigate the gut microbiota composition of SI and stool in IBS patients. Materials and methods Biopsies of jejunum mucosa by balloon-assisted enteroscopy and faecal samples from 28 IBS patients and 19 healthy controls were analysed by next-generation sequencing method. Results The three major phyla in SI microbiota of case/control groups were Proteobacteria (32.8/47.7%), Bacteroidetes (25.2/15.3%), and Firmicutes (19.8/11.2%), and those of stool were Bacteroidetes (41.3/45.8%), Firmicutes (40.7/38.2%), and Proteobacteria (15.4/7.1%). Analysis based on the family level, IBS patients had a higher proportion of Veillonellaceae (mean proportion 6.49% versus 2.68%, p?=?0.046) in stool than controls. Prevotellaceae was more abundant in IBS patients than in control group (14.27% versus 6.13%, p?=?0.023), while Mycobacteriaceae (0.06% versus 0.17%, p?=?0.024) and Neisseriaceae (6.40% versus 8.94%, p?=?0.038) was less abundant in IBS patients’ jejunal mucosa than those in controls. This less abundant jejunal Neisseriaceae was associated with more severe IBS (p?=?0.03). The ratio of Firmicutes to Bacteroidetes in the stool of IBS-diarrhoea type patients was approximately three-fold higher, and the ratio of Firmicutes to Actinobacter in SI of IBS-mixed type patients was about nine-fold higher than healthy subjects. Conclusion Higher abundance of colonic Veillonellaceae and SI Prevotellaceae, and lower amount of oral cavity normal flora in proximal SI were found in IBS patients. We may manipulate these bacteria in IBS patients in future studies (ClinicalTrial.gov Number NCT01679730).     

益生菌和肠易激综合征的关系

肠易激综合征(IBS)是最常见的功能性胃肠病之一,其发病机制目前还不明确。近年发现肠道微生物群可能参与了IBS的发生发展,细菌感染可以诱发感染后IBS;有一部分IBS患者存在小肠细菌过度生长(SIBO)或是菌群组成改变;口服肠道不吸收的抗生素能够减轻IBS的症状。因此有人提出用益生菌治疗IBS可能是一个合理的方法。此文就益生菌治疗IBS的相关研究作一综述。     

Changing face of irritable bowel syndrome

Recent years have witnessed tremendous progress in ourunderstanding of irritable bowel syndrome (IBS).It isevident that this is a truly global disease associated withsignificant symptoms and impairments in personal andsocial functioning for afflicted individuals.Advances inour understanding of gut flora-mucosal interactions,theenteric nervous system and the brain-gut axis have ledto substantial progress in the pathogenesis of symptomsin IBS and have provided some hints towards the basicetiology of this disorder,in some subpopulations,at thevery least.We look forward to a time when therapy willbe addressed to pathophysiology and perhaps,evento primary etiology.In the meantime,a model basedon a primary role for intestinal inflammation serves tointegrate the various strands,which contribute to thepresentation of IBS     

Cellular and molecular basis of intestinal barrier dysfunction in the irritable bowel syndrome

The etiopathogenesis of the irritable bowel syndrome (IBS), one of the most prevalent gastrointestinal disorders, is not well known. The most accepted hypothesis is that IBS is the result of the disturbance of the 'brain-gut axis.' Although the pathophysiological mechanisms of intestinal dysfunction are complex and not completely understood, stress, infections, gut flora, and altered immune response are thought to play a role in IBS development. The intestinal barrier, composed of a single-cell layer, forms a physical barrier that separates the intestinal lumen from the internal milieu. The loss of integrity of this barrier is related with mucosal immune activation and intestinal dysfunction in IBS. The number of mast cells and T lymphocytes is increased in the intestinal mucosa of certain IBS patients, and the mediators released by these cells could compromise the epithelial barrier function and alter nerve signaling within the enteric nervous system. The association of clinical symptoms to structural and functional abnormalities of the mucosal barrier in IBS patients highlights the importance of understanding the physiological role of the gut barrier in the pathogenesis of this disorder. This review summarizes the clinical and experimental evidences indicating the cellular and molecular mechanisms of IBS symptomatology, and its relevance for future translational research.     

Gut microbiota and irritable bowel syndrome

Irritable bowel syndrome (IBS) is a common gastrointestinal disorder that poses a significant health concern. Although its etiology remains unknown, there is growing evidence that gut dysbiosis is involved in the development and exacerbation of IBS. Previous studies have reported altered microbial diversity, abundance, and composition in IBS patients when compared to controls. However, whether dysbiosis or aberrant changes in the intestinal microbiota can be used as a hallmark of IBS remains inconclusive. We reviewed the literatures on changes in and roles of intestinal microbiota in relation to IBS and discussed various gut microbiota manipulation strategies. Gut microbiota may affect IBS development by regulating the mucosal immune system, brain–gut–microbiome interaction, and intestinal barrier function. The advent of high-throughput multi-omics provides important insights into the pathogenesis of IBS and promotes the development of individualized treatment for IBS. Despite advances in currently available microbiota-directed therapies, large-scale, well-organized, and long-term randomized controlled trials are highly warranted to assess their clinical effects. Overall, gut microbiota alterations play a critical role in the pathophysiology of IBS, and modulation of microbiota has a significant therapeutic potential that requires to be further verified.     

Gut microbiota role in irritable bowel syndrome: New therapeutic strategies

In the last decade the impressive expansion of our knowledge of the vast microbial community that resides in the human intestine, the gut microbiota, has provided support to the concept that a disturbed intestinal ecology might promote development and maintenance of symptoms in irritable bowel syndrome(IBS). As a correlate, manipulation of gut microbiota represents a new strategy for the treatment of this multifactorial disease. A number of attempts have been made to modulate the gut bacterial composition, following the idea that expansion of bacterial species considered as beneficial(Lactobacilli and Bifidobacteria) associated with the reduction of those considered harmful(Clostridium, Escherichia coli, Salmonella, Shigella and Pseudomonas) should attenuate IBS symptoms. In this conceptual framework, probiotics appear an attractive option in terms of both efficacy and safety, while prebiotics, synbiotics and antibiotics still need confirmation. Fecal transplant is an old treatment translated from the cure of intestinal infective pathologies that has recently gained a new life as therapeutic option for those patients with a disturbed gut ecosystem, but data on IBS are scanty and randomized, placebo-controlled studies are required.     

Recent advances in pharmacological treatment of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a highly prevalent functional disorder that reduces patients’ quality of life. It is a chronic disorder characterized by abdominal pain or discomfort associated with disordered defecation in the absence of identifiable structural or biochemical abnormalities. IBS imposes a significant economic burden to the healthcare system. Alteration in neurohumoral mechanisms and psychological factors, bacterial overgrowth, genetic factors, gut motility, visceral hypersensitivity, and immune system factors are currently believed to influence the pathogenesis of IBS. It is possible that there is an interaction of one or more of these etiologic factors leading to heterogeneous symptoms of IBS. IBS treatment is predicated upon the patient’s most bothersome symptoms. Despite the wide range of medications and the high prevalence of the disease, to date no completely effective remedy is available. This article reviews the literature from January 2008 to July 2013 on the subject of IBS peripherally acting pharmacological treatment. Drugs are categorized according to their administration for IBS-C, IBS-D or abdominal pain predominant IBS.     

青岛地区感染后肠易激综合征的临床特点

目的 调查分析青岛地区感染后肠易激综合征(PI-IBS)患者的临床特点.方法 收集门诊1BS患者,采用问卷调查方式,内容包括一般资料、症状和微生态制剂治疗前后的生活质量表.结果 (1)PI-IBS患者中女性患病率是男性的2.2倍,与非感染后肠易激综合征(non-PI-IBS)相近;(2)PI-IBS与non-PI-IBS患者都以脑力劳动者居多;(3)PI-IBS与non-PI-IBS患者的消化系统以外的伴随症状中,以躯体性不适为主的表现(疲劳、头痛、头晕、背痛等)的差异无统计学意义(X<'2>=10.5,P>0.05),而以精神性不适为主的表现(紧张、多疑、抑郁、焦虑等)PI-IBS要明显多于non-PI-IBS,差异有统计学意义(X<'2>=28.7,P<0.05);(4)PI-IBS的肠道菌群失调率明显高于non-PI-IBS患者;(5)PI-IBS患者在双歧三联活菌治疗1个月后,生活质最评分的差异有统计学意义(t=3.8,P<0.01),而non-PI-IBS患者治疗前后的差异无统计学意义(t=1.5,P>0.05).结论 青岛地区PI-IBS与non-PI-IBS的某些临床特点存在差异.     

Intestinal microbiota in pathophysiology and management of irritable bowel syndrome

Irritable bowel syndrome (IBS) is a functional bowel disorder without any structural or metabolic abnormalities that sufficiently explain the symptoms, which include abdominal pain and discomfort, and bowel habit changes such as diarrhea and constipation. Its pathogenesis is multifactorial: visceral hypersensitivity, dysmotility, psychosocial factors, genetic or environmental factors, dysregulation of the brain-gut axis, and altered intestinal microbiota have all been proposed as possible causes. The human intestinal microbiota are composed of more than 1000 different bacterial species and 10¹⁴ cells, and are essential for the development, function, and homeostasis of the intestine, and for individual health. The putative mechanisms that explain the role of microbiota in the development of IBS include altered composition or metabolic activity of the microbiota, mucosal immune activation and inflammation, increased intestinal permeability and impaired mucosal barrier function, sensory-motor disturbances provoked by the microbiota, and a disturbed gut-microbiota-brain axis. Therefore, modulation of the intestinal microbiota through dietary changes, and use of antibiotics, probiotics, and anti-inflammatory agents has been suggested as strategies for managing IBS symptoms. This review summarizes and discusses the accumulating evidence that intestinal microbiota play a role in the pathophysiology and management of IBS.     

褪黑激素与肠易激综合征

肠易激综合征是一种原因不明的慢性肠功能紊乱性疾病，其发病机制尚不清楚。其治疗方法也在不断改进中，褪黑激素对肠易激综合征的治疗有着积极的作用。