Probiotics and prebiotics in chronic inflammatory bowel diseases

INTRODUCTION At birth, the gastrointestinal tract is a sterile environment. Initial exposure of the gut to microbes occurs during the birthing process from the maternal fecal and vaginal ? ora. Within a few months after birth, a relatively stable microbia…     

肠道菌群与动脉粥样硬化的关系

动脉粥样硬化(As)是心血管疾病(CVD)的主要病理基础且其发病机制具有多样性。肠道菌群失调可通过代谢和免疫系统导致代谢失调和炎症反应,导致斑块形成和破裂,细菌感染在As形成和斑块的发展也具有一定的影响。同时肠道菌群失调可改变胆固醇代谢和菌群代谢物如氧化三甲胺(TMAO)、胆汁酸(BAs)和短链脂肪酸(SCFAs)水平影响As发病进程。目前以肠道菌群为靶点治疗As的研究逐渐深入,益生菌、益生元、粪菌移植、中药可能是未来As治疗的潜在方法并使CVD患者获益。     

Diet, anaerobic bacterial metabolism, and colon cancer: a review of the literature

Epidemiologic studies have demonstrated variations in the incidence of colon cancer between populations and socioeconomic groups. Differences in dietary habits have been implicated in the risk of developing colon cancer. Diet appears to influence our colonic microflora. Such variations may allow for future utilization of the fecal flora as markers for screening and diagnosis of colon cancer. The composition of the diet not only dictates the available substrates for the flora but also helps to establish predictable and competitive relationships between intestinal bacteria. To appreciate the significance of populations deemed high and low risk based on host flora, an understanding of several dynamic microbial relationships and metabolites produced is necessary. In this review, we explore the critical relationships between bile acid 7 alpha-dehydroxylation, sulfidogenesis, methanogenesis, and how they relate to carbohydrate and bile acid metabolism. We summarize the chemopreventative, anticarcinogenic, and detoxifying activity of probiotics and prebiotics, as well as potential mechanisms for protection against colon cancer.     

Intestinal microbiota and type 2 diabetes: From mechanism insights to therapeutic perspective

The incidence of type 2 diabetes (T2DM) is rapidly increasing worldwide. However, the pathogenesis of T2DM has not yet been well explained. Recent evidence suggests that the intestinal microbiota composition is associated with obesity and T2DM. In this review, we provide an overview about the mechanisms underlying the role of intestinal microbiota in the pathogenesis of T2DM. There is clear evidence that the intestinal microbiota influences the host through its effect on body weight, bile acid metabolism, proinflammatory activity and insulin resistance, and modulation of gut hormones. Modulating gut microbiota with the use of probiotics, prebiotics, antibiotics, and fecal microbiota transplantation may have benefits for improvement in glucose metabolism and insulin resistance in the host. Further studies are required to increase our understanding of the complex interplay between intestinal microbiota and the host with T2DM. Further studies may be able to boost the development of new effective therapeutic approaches for T2DM.     

Relationship between intestinal microbiota and ulcerative colitis: Mechanisms and clinical application of probiotics and fecal microbiota transplantation

Ulcerative colitis(UC) is an inflammatory disease that mainly affects the colon and rectum. It is believed that genetic factors, host immune system disorders, intestinal microbiota dysbiosis, and environmental factors contribute to the pathogenesis of UC. however, studies on the role of intestinal microbiota in the pathogenesis of UC have been inconclusive. Studies have shown that probiotics improve intestinal mucosa barrier function and immune system function and promote secretion of anti-inflammatory factors, thereby inhibiting the growth of harmful bacteria in the intestine. Fecal microbiota transplantation(FMT) can reduce bowel permeability and thus the severity of disease by increasing the production of short-chain fatty acids, especially butyrate, which help maintain the integrity of the epithelial barrier. FMT can also restore immune dysbiosis by inhibiting Th1 differentiation, activity of T cells, leukocyte adhesion, and production of inflammatory factors. Probiotics and FMT are being increasingly used to treat UC, but their use is controversial because of uncertain efficacy. Here, we briefly review the role of intestinal microbiota in thepathogenesis and treatment of UC.     

Update on intestinal microbiota in Crohn's disease 2017: Mechanisms,clinical application,adverse reactions,and outlook

The pathogenesis of Crohn's disease (CD) is complex, and it is thought to be associated with the environment, immune, hereditary, microbe, and other factors. If the balance between the host and the intestinal microbes in CD patients was broken, immune‐inflammatory response of susceptible individuals might be triggered. Probiotics could improve the intestinal microbial flora balance and treat human effectively. There are several new mechanisms that might explain the role of probiotics. Fecal microbiota transplantation (FMT) is becoming more and more attractive in treating a large amount of digestive system diseases that are related to the dysbiosis of intestinal microbiota. FMT has been widely used in recurrent Clostridium difficile infection. More and more attention has been paid on the clinical application of FMT in CD, while the exact mechanism is still a mystery. So in this review, we explore the mechanism, clinical application, and adverse reactions of intestinal microbiota in CD so that we can use the tool to cure more diseases. Enteric microbiota leads to new therapeutic strategies for CD.     

肠道菌群与疾病关系的研究进展

多种疾病与肠道菌群失衡有关。肠道微生物参与宿主新陈代谢和免疫系统的调节,并与环境因子相互作用决定机体的健康和疾病状态。本文就肠道菌群与代谢综合征、炎症性肠病和结直肠癌等疾病关系的研究进展作一综述,进一步揭示了肠道微生物在人类健康中起到的重要作用,并通过介绍益生菌和粪菌移植等方法,为探索治疗诸多疾病提供新的方向。     

Prebiotics, probiotics, and dietary fiber in gastrointestinal disease

Microecology of the gastrointestinal tract is the physiologic basis for the effect of dietary fiber, prebiotics and probiotics on the host. The ecology consists of the gastrointestinal tract, primarily the intestines, the foods that are fed into the tract, and the flora living within. Within this ecology, normal flora and probiotics, ferment dietary fiber and prebiotics to produce short chain fatty acids and substances that are absorbed and effect the host at the intestinal level and systemically. In this review, we will discuss the effects of prebiotics, probiotics and dietary fiber in gastrointestinal disorders and diseases.     

Therapeutic methods of gut microbiota modification in colorectal cancer management – fecal microbiota transplantation,prebiotics, probiotics,and synbiotics

ABSTRACT

The link between gut microbiota and the development of colorectal cancer has been investigated. An imbalance in the gut microbiota promotes the progress of colorectal carcinogenesis via multiple mechanisms, including inflammation, activation of carcinogens, and tumorigenic pathways as well as damaging host DNA. Several therapeutic methods are available with which to alter the composition and the activity of gut microbiota, such as administration of prebiotics, probiotics, and synbiotics; these can confer various benefits for colorectal cancer patients. Nowadays, fecal microbiota transplantation is the most modern way of modulating the gut microbiota. Even though data regarding fecal microbiota transplantation in colorectal cancer patients are still rather limited, it has been approved as a clinical method of treatment-recurrent Clostridium difficile infection, which may also occur in these patients. The major benefits of fecal microbiota transplantation include modulation of immunotherapy efficacy, amelioration of bile acid metabolism, and restoration of intestinal microbial diversity. Nonetheless, more studies are needed to assess the long-term effects of fecal microbiota transplantation. In this review, the impact of gut microbiota on the efficiency of anti-cancer therapy and colorectal cancer patients’ overall survival is also discussed.     

Gut flora in health and disease

The human gut is the natural habitat for a large and dynamic bacterial community, but a substantial part of these bacterial populations are still to be described. However, the relevance and effect of resident bacteria on a host's physiology and pathology has been well documented. Major functions of the gut microflora include metabolic activities that result in salvage of energy and absorbable nutrients, important trophic effects on intestinal epithelia and on immune structure and function, and protection of the colonised host against invasion by alien microbes. Gut flora might also be an essential factor in certain pathological disorders, including multisystem organ failure, colon cancer, and inflammatory bowel diseases. Nevertheless, bacteria are also useful in promotion of human health. Probiotics and prebiotics are known to have a role in prevention or treatment of some diseases.     

Prebiotics as gut microflora management tools

Functional foods is an often-used term applied to dietary ingredients that serve to improve consumer health. Over the last few decades, these foods have gained in popularity with sales continuing to increase rapidly. Recent scientific, and some lay, reports have shown the popularity of both probiotics and prebiotics. These serve to elicit changes in the gut microbiota composition that increase populations of purported beneficial gut bacterial genera, for example, lactobacilli or bifidobacteria. Probiotics use live microbial feed additions, whereas prebiotics target indigenous flora components. As gastrointestinal disorders are prevalent in terms of human health, both probiotics and prebiotics serve an important role in the prophylactic management of various acute and chronic gut derived conditions. Examples include protection from gastroenteritis and some inflammatory conditions.     

Intestinal Flora Dysbiosis Aggravates Cognitive Dysfunction Associated With Neuroinflammation in Heart Failure

BackgroundCognitive dysfunction after heart failure (HF) is characterized by neuroinflammation, which plays an important role in the occurrence and development of cognitive dysfunction. Recent studies have shown that an intestinal flora imbalance may also trigger neuroinflammation in Alzheimer’s disease. The present study was designed to reveal that intestinal flora dysbiosis caused by HF aggravates neuroinflammation-associated cognitive impairment.Methods and ResultsAdult male Sprague-Dawley rats were fed daily for 2 weeks with probiotics or placebo until the day of surgery. HF was then triggered by 8 weeks of sustained coronary artery occlusion. 16S rDNA sequencing was used to confirm intestinal flora dysbiosis after HF and demonstrate that the changes paralleled intestinal pathology scores. The permeability of the blood–brain barrier was increased after HF, and such an increase in permeability may increase the levels of inflammatory cytokines caused by intestinal flora disorders. The changes in the intestinal flora caused by probiotics significantly reduced the level of neuroinflammation. In addition, probiotic administration considerably improved the impaired spatial memory in HF rats.ConclusionsWe conclude that intestinal flora dysbiosis plays a potential role in aggravating the impaired cognition associated with neuroinflammation and that these effects may be attenuated by probiotics.     

Bacteriotherapy using fecal flora: toying with human motions

The intestinal flora may play a key role in the pathogenesis of certain gastrointestinal (GI) diseases. Components of bowel flora such as Lactobacillus acidophilus and Bifidobacterium bifidus have long been used empirically as therapeutic agents for GI disorders. More complex combinations of probiotics for therapeutic bacteriotherapy have also recently become available, however the most elaborate mix of human-derived probiotic bacteria is, by definition, the entire fecal flora. Fecal bacteriotherapy uses the complete normal human flora as a therapeutic probiotic mixture of living organisms. This type of bacteriotherapy has a longstanding history in animal health and has been used sporadically against chronic infections of the bowel, especially as a treatment of last resort for patients with severe Clostridium difficile syndromes including recurrent diarrhea, colitis, and pseudomembranous colitis. Encouraging results have also been observed following infusions of human fecal flora in patients with inflammatory bowel disease, irritable bowel syndrome, and chronic constipation. The therapeutic use of fecal bacteriotherapy is reviewed here and possible mechanisms of action and potential applications explored. Published reports on fecal bacteriotherapy are few in number, and detail the results of small uncontrolled open studies and case reports. Nevertheless, given the promising clinical responses, formal research into fecal bacteriotherapy is now warranted.     

Probiotics and inflammatory bowel disease: is there a scientific rationale?

Most conventional forms of drug therapy suppress or modify the host immunoinflammatory response and neglect the other contributor to disease pathogenesis-the environmental microflora. Probiotics are live microbial food ingredients that alter the enteric microflora and have a beneficial effect on health. The rationale for using probiotics in IBD is mainly based on evidence from human studies and experimental animal models implicating intestinal bacteria in the pathogenesis of these disorders. The relationship between bacteria and intestinal inflammation is complex and does not appear to reflect a simple cause and effect. Similarly, the field of probiotics is complex and in need of rigorous research. Until the indigenous flora are better characterized and mechanisms of probiotic action defined, the promise of probiotics in IBD is unlikely to be fulfilled. Because of strain-specific variability and clinical and therapeutic heterogeneity within Crohn's disease and ulcerative colitis, it cannot be assumed that a given probiotic is equally suitable for all individuals. Although preliminary results of probiotic therapy in animal models and humans with ulcerative colitis and pouchitis have been encouraging, their efficacy in treatment or maintenance of remission of Crohn's disease remains to be clarified. However, the circumstantial evidence for some form of biotherapeutic modification of the enteric flora in Crohn's disease seems compelling. In the future, probiotics may offer a simple adjunct to conventional therapy with the emphasis on diet shifting from one of nutritional replenishment alone to a more functional role.     

The microbiome and obesity: Is obesity linked to our gut flora?

The human gut is a lush microbial ecosystem containing about 100 trillion microorganisms, whose collective genome, the microbiome, contains 100-fold more genes than the entire human genome. The symbiosis of our extended genome plays a role in host homeostasis and energy extraction from diet. In this article, we summarize some of the studies that have advanced the understanding of the microbiome and its effects on metabolism, obesity, and health. Metagenomic studies demonstrated that certain mixes of gut microbiota may protect or predispose the host to obesity. Furthermore, microbiota transplantation studies in germ-free murine models showed that the efficient energy extraction traits of obese-type gut flora are transmissible. The proposed methods by which the microbiome may contribute to obesity include increasing dietary energy harvest, promoting fat deposition, and triggering systemic inflammation. Future treatments for obesity may involve modulation of gut microbiota using probiotics or prebiotics.     

Therapeutic alteration of the microbiota in rheumatic diseases: Hype or potential?

Multiple studies have demonstrated abnormalities in the contents of the fecal microbiota in patients with a variety of forms of arthritis. This has prompted interest in microbial-altering therapy as a therapeutic tool. While antibiotics as a long-term therapeutic tool have largely fallen out of favor, there have been multiple studies evaluating probiotics in rheumatoid arthritis, spondyloarthritis, or systemic sclerosis; a small number of studies have tested fecal microbial transplantation (FMT) in rheumatic diseases. Although probiotics were well tolerated, few studies detected meaningful clinical benefit regardless of indication. Likewise, one of the two randomized studies evaluating FMT showed minimal clinical benefit, while the other demonstrated worsening compared to sham treatment. In this review article, I summarize the literature on probiotics and FMT in rheumatic diseases, discuss potential reasons for the absence of demonstrable benefit, and suggest avenues of future direction of research.     

Probiotics and Prebiotics in Infants and Children

Probiotics and prebiotics have a major influence on gastrointestinal flora composition. This review analyses the relationship between this change in flora composition and health benefits in children. Literature databases were searched for relevant articles. Despite exhaustive research on the subject in different indications, such as prevention and treatment of acute gastroenteritis, antibiotic associated diarrhea (AAD), traveler's diarrhea, inflammatory bowel disease, irritable bowel syndrome, Helicobacter pylori, necrotizing enterocolitis, constipation, allergy and atopic dermatitis, colic and extraintestinal infections, reports of clear benefits for the use of prebiotics and probiotics in pediatric disorders remain scarce. The best evidence has been provided for the use of probiotics in acute gastroenteritis and in prevention of AAD. However, AAD in children is in general mild, and only seldom necessitates additional interventions. Overall, the duration of acute infectious diarrhea is reduced by approximately 24 hours. Evidence for clinically relevant benefit in all other indications (inflammatory bowel disease, irritable bowel syndrome, constipation, allergy) is weak to nonexistent. Selected probiotic strains given during late pregnancy and early infancy decrease atopic dermatitis. Adverse effects have very seldom been reported. Since the risk seems minimal to nonexistent, prebiotics and probiotics may be helpful in the prevention and treatment of some disorders in children, although the evidence for benefit is limited. The best evidence has been accumulated for some lactobacilli strains and for Saccharomyces boulardii in the reduction of the duration of acute diarrhea due to gastroenteritis and prevention of AAD.     

Fecal microbiota transplantation for managing irritable bowel syndrome

Introduction: Irritable bowel syndrome (IBS) is a widespread gastrointestinal disorder affecting 11.2% of the world adult population. The intestinal microbiome is thought to play a pivotal role in the pathophysiology of IBS. The composition of the fecal microbiome in IBS patients differs from that in healthy individuals, but the exact bacteria species involved in the development of IBS remain to be determined. There is also an imbalance between useful and harmful bacteria (dysbiosis) in the intestinal microbiome in patients with IBS. Consuming prebiotics, probiotics, or synbiotics has a limited effect on IBS symptoms. In contrast, fecal microbiome transplantation (FMT) in IBS patients reverses the dysbiosis to normobiosis and reduces the IBS symptoms in about 70% of patients, and is not associated with any serious adverse events.

Area covered: The available data on the microbiome and FMT in IBS regarding the efficacy of FMT in managing IBS were found using a PubMed search of these topics.

Expert commentary: FMT is a promising tool for managing irritable syndrome. It appears to be effective, easy, and inexpensive procedure. However, more controlled studies involving larger cohorts of IBS are needed before FMT can be used as a routine procedure in the clinic.     

Can control of gut microbiota be a future therapeutic option for inflammatory bowel disease?

Inflammatory bowel disease (IBD) is a chronic inflammatory condition of the gastrointestinal tract encompassing two main clinical entities, Crohn’s disease and ulcerative colitis. Accumulated evidence indicates that an aberrant immune activation caused by the interplay of genetic susceptibility and environmental impact on the gut microbiota may be involved in the pathogenesis of IBD. Rapid advances in next-generation sequencing technology have enabled a number of studies to identify the alteration of the gut microbiota, termed dysbiosis, in IBD. Moreover, the alteration in the metabolites derived from the gut microbiota in IBD has also been described in many studies. Therefore, microbiota-based interventions such as fecal microbiota transplantation (FMT) have attracted attention as a novel therapeutic option in IBD. However, in clinical trials, the efficacy of FMT for IBD remains controversial. Additional basic and clinical studies are required to validate whether FMT can assume a complementary role in the treatment of IBD. The present review provides a synopsis on dysbiosis in IBD and on the association between the gut microbiota and the pathogenesis of IBD. In addition, we summarize the use of probiotics in IBD and the results of current clinical trials of FMT for IBD.