益生菌对肠易激综合征和炎症性肠病的作用

由于胃肠道微生物参与炎症性肠病（inflammatory bowel disease,IBD）的病理过程,而且最近研究表明微生物可能在肠易激综合征（irritable bowel syndrome,IBS）中扮演重要作用.本文重点关注益生菌在这两种疾病中的作用机制和疗效.胃肠道微生物的组成受多种因素调节,包括年龄、饮食和疾病状态.益生菌可能通过影响宿主的微生物菌群和提高黏膜的免疫调节作用发挥疗效.益生菌的口服耐受性较好.许多短期研究表明益生菌在IBS中有效,尽管只是在部分的特殊菌株和某些特定症状中有效.在IBD中,许多临床试验表明大量的益生菌在结肠袋炎和溃疡性结肠炎中有效,而对克罗恩病无明显疗效.显然,益生菌在IBS和IBD的治疗中能起到巨大的作用,但是,这些只是针对特殊的菌株.将来迫切需要进行高质量的临床研究和实验观察益菌对IBD和IBS的疗效.     

益生菌与消化道健康

人体胃肠道内细菌与宿主具有特殊的关系。胃肠道内细菌,特别是益生菌对维持肠黏膜屏障功能、调节机体免疫功能和促进营养物质的吸收具有重要作用,与人体健康密切相关。肠道菌群紊乱与功能性消化不良、腹泻、便秘、炎症性肠病等胃肠道症状和多种疾病有关,补充外源性益生菌具有较好的临床疗效。本文对肠内益生菌与消化健康的关系作一简要概述。     

鼠李糖乳杆菌GG防治消化系统疾病的研究进展

鼠李糖乳杆菌GG(LGG)是目前研究较广泛的益生菌之一,在人类胃肠道中具有良好的黏附及定植能力.LGG可通过多种途径起到保护胃肠道的作用,由于其独特的生物学功能,目前LGG已被用于预防和治疗多种胃肠道微生态失调相关疾病.该文就LGG防治消化系统疾病(包括幽门螺杆菌感染、急性感染性腹泻、旅行者腹泻、抗生素相关腹泻、功能性...     

益生菌在根除幽门螺杆菌治疗中的作用

幽门螺杆菌(Helicobacter pylori,H.pylori)感染与上胃肠道疾病密切相关。由于H.pylori对抗生素耐药率的增加及根除治疗过程中不良反应的出现,导致标准三联疗法H.pylori根除率逐渐下降。益生菌辅助治疗H.pylori感染已取得一些成果,其在提高H.pylori根除率、降低不良反应中的作用日益受到重视。在H.pylori根除治疗中何时加用益生菌、加用何种益生菌成为国内外研究的热点,益生菌的疗效很大程度上依赖于菌种或菌株类型。益生菌还具有维持胃肠道微生态的稳定、减轻黏膜炎症反应等多种作用,本文对益生菌在根除H.pylori治疗中的作用机制及临床意义、益生菌在降低H.pylori治疗相关不良反应中的作用作一概述。     

益生菌对肠道上皮细胞保护机制的研究进展

肠上皮细胞(intestinal epithelial cells,IECs)是机体抵御病原微生物的第一道防线,是联系宿主和肠道微生物的主要桥梁.IECs与微生物的相互作用可能会引起免疫失调,然而益生菌能通过屏障与免疫调节功能来预防肠道疾病的发生.首先,益生菌具有生物拮抗功能,可以通过争夺营养,代谢产物,以及占位效应来调节肠道内微生物菌群,抑制肠道外源性潜在致病菌的生长;其次,益生菌能够改善机体的免疫功能,IECs通过模式识别受体识别益生菌及代谢产物,调节多个信号通路,调控受体的表达,激发机体自身非特异性免疫应答,从而产生一系列的免疫保护反应.另外,益生菌能够诱导肠道上皮细胞产生大量富含黏蛋白的黏液,黏液保护肠黏膜不与病原微生物接触,阻止细菌黏附于上皮细胞,从而保护肠道的屏障.临床试验进一步证实了益生菌是潜在的感染性肠炎如克罗恩病和溃疡性结肠炎治疗方式.     

益生菌在抗肠道寄生虫病感染中的作用

益生菌是一类对宿主有益的活性微生物,可以有效治疗胃肠道、呼吸道感染和过敏性疾病。虽然目前主要用于治疗细菌和病毒感染,但也有研究表明益生菌对寄生虫感染有抑制作用。因此,以益生菌制成的微生态制剂将为寄生虫防治提供一种新的途径。     

肠道微生物与结直肠癌发生发展关系的研究进展

近些年来,人们越来越关注肠道微生物在结直肠癌中的作用。大量研究已经表明肠道微生物在结直肠癌发生发展过程中发挥着重要的功能。通过益生菌或益生元调节肠道微生态平衡可以达到预防和治疗结直肠癌的目的。本综述围绕肠道微生物与结直肠癌发生发展的关系以及益生菌参与抑制结直肠癌的机制进行论述,为研究该疾病发生发展机制及预防治疗等提供一些思路。     

益生菌的作用机制

益生菌是一种适当摄取后能对机体产生有益作用的微生物。研究表明各种益生菌的作用不同,这与服用剂量、频次密切相关。有些益生菌可生成抗菌物质如抗菌素,可在肠腔内发挥作用;有些可通过增加固有的免疫应答产物,如杯状细胞来源的黏蛋白、潘式细胞来源的防御素,来增强肠道黏膜屏障功能;有些可通过增强获得性免疫应答来促进机体健康;有些则可激活肠道神经系统的某些受体,来缓解由于内脏高敏感性造成的疼痛。此文就益生菌的作用机制作一综述。     

益生菌在胃相关性疾病中的研究进展

益生菌是指对人体有益的细菌的总称,它广泛存在于人类胃肠道内,在维持人体胃肠道微生态平衡中起着重要的作用。大量研究已证实益生菌对各种肠道疾病的确有一定的治疗作用,而针对胃相关疾病的研究较少。此文就益生菌在胃相关疾病中的研究进展作一综述。     

益生菌在肠易激综合征治疗中的作用

肠易激综合征(irritable bowel syndrome,IBS)是一组以排便后可缓解或减轻的腹痛或腹部不适为主要症状的功能性肠道疾病.近年来,益生菌用于IBS治疗的疗效引起了人们的兴趣和重视.益生菌是指摄人一定数量,能以活菌状态到达宿主胃肠道,以治疗和预防疾病的微生物.人体内的益生菌包括乳酸杆菌属、双歧杆菌属、芽孢杆菌属等.     

Clinical Uses of Probiotics

Probiotics are live nonpathogenic microorganisms. Many of these microorganisms are part of the normal human gut flora, where they live in a symbiotic relationship. Probiotics have been used to treat gastrointestinal (GI) and non-GI medical conditions. However, the data supporting their use are often conflicting, especially for non-GI-associated illnesses. The strongest evidence supporting the use of probiotics is related to the treatment of acute diarrhea and pouchitis. Atopic eczema in children and genitourinary infections are the only non-GI-related medical conditions where probiotics may have some beneficial effects. Product selection and dosing are not the same in all conditions, and the beneficial effects of each probiotic strain cannot be generalized.The purpose of this article is to provide most recent information about probiotics and its uses. In contrast with previously published reviews on probiotics, we also discuss the composition of various products (Table 1), indications for their use (Table 2), product selection, and dosing of probiotics.Probiotics are safe and appear to exert some beneficial effects in GI-related illnesses. The use of probiotics in non-GI illnesses is not sufficiently supported by current data.     

Probiotics for the Treatment of Inflammatory Bowel Disease

Probiotics are organisms which provide a desired and beneficial effect on human health. With recent evidence implicating a disruption in the balance of the gastrointestinal microbiome and intestinal immunity as a potential trigger for inflammatory bowel disease (IBD), there has been growing interest in using probiotics as an adjunct to standard anti-inflammatory and immune suppressing therapy. Animal models describe potential and plausible mechanisms of action for probiotics to counter inflammation of colonic mucosa. Although there are insufficient data to recommend probiotics in ulcerative colitis or Crohn's disease, good evidence supports the use of specific probiotics for maintenance of remission in pouchitis. Although there are limited regulatory standards for the agents, probiotics are relatively safe with minimal reported side effects or contraindications. More rigorous studies need to be published supporting efficacy and safety of these agents before they become a mainstay of IBD medical treatment.     

Effects of probiotics on the gastrointestinal tract

PURPOSE OF REVIEW: This review summarizes recent developments in our understanding of what gastrointestinal disorders probiotics can be of benefit for, focussing on conditions associated with infection or disruption of the normal gut flora. New insights into the effects administered strains can have in the gut, their safety, and potential for future development, will also be discussed. RECENT FINDINGS: Recent clinical studies have shown that probiotics can protect young children from diarrhoeal illness, including antibiotic-associated diarrhoea. They may also protect neonates from necrotizing enterocolitis. In adults, they can help prevent or reduce the severity of diarrhoeal illness, and ameliorate side-effects for those undergoing antibiotic therapy for infection. Researchers are looking at combining probiotics with prebiotics to enhance anti-inflammatory effects and restore colonization resistance of the commensal flora. New technologies are elucidating complex effects on gene expression in the gut, the probiotic, and bacterial pathogens. Recombinant strains capable of binding bacterial toxins are being developed as novel therapeutics against gastrointestinal infection. SUMMARY: Considering the clinical trial evidence of therapeutic benefit, probiotics are an underused treatment modality for prevention and amelioration of diarrhoeal illness. Better understanding of strain-specific effects, dosing regimens and any contraindications should help resolve this.     

Probiotics in infective diarrhoea and inflammatory bowel diseases

Bacteria are present throughout the gastrointestinal tract, but their pattern and concentration vary greatly. Probiotics are living organisms that supply beneficial health effects to the host. So far the beneficial effects of probiotics have been shown, almost exclusively, under poorly defined experimental conditions. There are little convincing data from well-designed, double-blind controlled trials supporting health-promoting effects. The use of probiotics to treat gastrointestinal infections has produced contrasting results. Apart from information on rotavirus infection in children, there is no convincing evidence from controlled studies on the efficacy of probiotics in the prevention or treatment of infective diarrhoea. However, experimental and clinical studies suggest that there are potential therapeutic roles for probiotics in the treatment of inflammatory bowel diseases. This review focuses on the available data concerning the mechanisms of action of probiotics, and on the results from clinical studies using probiotics to treat infective diarrhoea and inflammatory bowel disease.     

Probiotics against neoplastic transformation of gastric mucosa: Effects on cell proliferation and polyamine metabolism

Gastric cancer is still the second leading cause of cancer death worldwide, accounting for about 10% of newly diagnosed neoplasms. In the last decades, an emerging role has been attributed to the relations between the intestinal microbiota and the onset of both gastrointestinal and non-gastrointestinal neoplasms. Thus, exogenous microbial administration of peculiar bacterial strains (probiotics) has been suggested as having a profound influence on multiple processes associated with a change in cancer risk. The internationally accepted definition of probiotics is live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. The possible effects on the gastrointestinal tract following probiotic administration have been investigated in vitro and in animal models, as well as in healthy volunteers and in patients suffering from different human gastrointestinal diseases. Although several evidences are available on the use of probiotics against the carcinogen Helicobacter pylori, little is still known about the potential cross-interactions among probiotics, the composition and quality of intestinal flora and the neoplastic transformation of gastric mucosa. In this connection, a significant role in cell proliferation is played by polyamines (putrescine, spermidine, and spermine). These small amines are required in both pre-neoplastic and neoplastic tissue to sustain the cell growth and the evidences here provided suggest that probiotics may act as antineoplastic agents in the stomach by affecting also the polyamine content and functions. This review will summarize data on the most widely recognized effects of probiotics against neoplastic transformation of gastric mucosa and in particular on their ability in modulating cell proliferation, paying attention to the polyamine metabolism.     

Probiotics: what are they? What are their effects on gut physiology?

Probiotics can be defined as microbial cells that have a beneficial effect on the health and well-being of the host. Since the gastrointestinal mucosa is the surface of contact with probiotics, it seems evident that the first effects of probiotics relate to digestive function. A brief review of the literature indicates that probiotics have very few effects on the main physiological functions of the gastrointestinal tract, which are digestion, absorption and propulsion. The main action of probiotics can be summarised as a reinforcement of the intestinal mucosal barrier against deleterious agents. Experimental data indicate that some probiotics reduce pathological alterations in paracellular permeability to large molecules or bacteria, stimulate mucosal immunity, display a trophic action on the mucosa, reduce mucus degradation and interact with mediators of inflammation. Yoghurt may help lactose digestion, and some data needing confirmation indicate a stimulation of water absorption and an acceleration of intestinal transit by some bacteria.     

Probiotics to enhance anti-infective defences in the gastrointestinal tract

Several clinical studies have demonstrated the therapeutic and/or prophylactic efficacy of specific probiotics against acute viral gastroenteritis and antibiotic-associated diarrhoea (including Clostridium difficile infection). Emerging evidence also suggests beneficial effects against Helicobacter pylori infection. The evidence of efficacy against traveller's diarrhoea remains, however, inconclusive. The precise mechanisms by which probiotics potentiate host gastrointestinal defences and mediate protection are not fully known. There is evidence to suggest, however, that probiotics might contribute to host defence by reinforcing non-immunological defences and stimulating both specific and non-specific host immune responses. Little is known about the relative importance of the probiotic-stimulated mechanisms in host protection. This review summarises the evidence for the anti-infective effects of probiotics and discusses the effect of orally delivered probiotics on non-immunological and immunological defence mechanisms in the host, especially in the gastrointestinal tract.     

World Gastroenterology Organisation practice guideline: Probiotics and prebiotics

The human gut harbors dense and diverse microbial communities which have an impact on host’s health. The symbiotic relationship between gut microbial communities and host can be optimized by pharmacological or nutritional intervention on the intestinal ecosystem using probiotics or prebiotics. Worldwide research on the use of prebiotics and probiotics in human and animal health has accelerated in recent years. However, there is lack of information about the practical use of probiotics and prebiotics in Medicine. A major area for medical applications has been the prevention or treatment of gastrointestinal diseases. Recently, a group of international experts appointed by the World Gastroenterology Organization prepared a practical guideline on the current indications of probiotics and prebiotics in Gastroenterology. The full text of the guideline is published in the current issue of our Journal. The document underscores strain-specificity of the clinical effects, and provides precise information on which specific probiotic strains or prebiotic compounds are useful for what particular clinical indications (see Table 3).     

Probiotics and irritable bowel syndrome

Irritable bowel syndrome(IBS)is common gastrointestinal problems.It is characterized by abdominal pain or discomfort,and is associated with changes in stool frequency and/or consistency.The etiopathogenesis of IBS may be multifactorial,as is the pathophysiology,which is attributed to alterations in gastrointestinal motility,visceral hypersensitivity,intestinal microbiota,gut epithelium and immune function,dysfunction of the brain-gut axis or certain psychosocial factors.Current therapeutic strategies are often unsatisfactory.There is now increasing evidence linking alterations in the gastrointestinal microbiota and IBS.Probiotics are living organisms which,when ingested in certain numbers,exert health benefits beyond inherent basic nutrition.Probiotics have numerous positive effects in the gastrointestinal tract.Recently,many studies have suggested that probiotics are effective in the treatment of IBS.The mechanisms of probiotics in IBS are very complex.The purpose of this review is to summarize the evidence and mechanisms for the use of probiotics in the treatment of IBS.