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1role of the normal gut microbiota显示文摘Relation between the gut microbiota and human health is being increasingly recognised. It is now well established that a healthy gut flora is largely responsible for overall health of the host. The normal human gut microbiota comprises of two major phyla, namely Bacteroidetes and Firmicutes. Though the gut microbiota in an infant appears haphazard, it starts resembling the adult flora by the age of 3 years. Nevertheless, there exist temporal and spatial variations in the microbial distribution from esophagus to the rectum all along the individual's life span. Developments in genome sequencing technologies and bioinformatics have now enabled scientists to study these microorganisms and their function and microbehost interactions in an elaborate manner both in health and disease. The normal gut microbiota imparts specific function in host nutrient metabolism, xenobiotic and drug metabolism, maintenance of structural integrity of the gut mucosal barrier, immunomodulation, and protection against pathogens. Several factors play a role in shaping the normal gut microbiota. They include(1) the mode of delivery(vaginal or caesarean);(2) diet during infancy(breast milk or formula feeds) and adulthood(vegan based or meat based); and(3) use of antibiotics or antibiotic like molecules that are derived from the environment or the gut commensal community. A major concern of antibiotic use is the long-term alteration of the normal healthy gut microbiota and horizontal transfer of resistance genes that could result in reservoir of organisms with a multidrug resistant gene pool.Sai Manasa Jandhyala Rupjyoti Talukdar Chivkula Subramanyam Harish Vuyyuru Mitnala Sasikala D Nageshwar Reddy 2015World Journal of Gastroenterology2015,21,29:187
2Relationship between intestinal microbiota and ulcerative colitis:Mechanisms and clinical application of probiotics and fecal microbiota transplantation显示文摘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.Zhao-hua Shen Chang-xin Zhu Yong-sheng Quan Zhen-yu Yang Shuai Wu Wei-wei Luo Bei Tan Xiao-yan Wang 2018World Journal of Gastroenterology2018,24,1:111
3Fecal microbiota transplantation for severe enterocolonic fistulizing Crohn's disease显示文摘The concept of fecal microbiota transplantation(FMT)has been used in traditional Chinese medicine at least since the 4thcentury.Evidence from recent human studies strongly supports the link between intestinal bacteria and inflammatory bowel disease.We proposed that standardized FMT might be a promising rescue therapy for refractory inflammatory bowel disease.However,there were no reports of FMT used in patients with severe Crohn’s disease(CD).Here,we report the successful treatment of standardized FMT as a rescue therapy for a case of refractory CD complicated with fistula,residual Barium sulfate and formation of intraperitoneal large inflammatory mass.As far as we know,this is the first case of severe CD treated using FMT through mid-gut.Fa-Ming Zhang Hong-Gang Wang Min Wang Bo-Ta Cui Zhi-Ning Fan Guo-Zhong Ji 2013World Journal of Gastroenterology2013,19,41:78
4Gut microbiota imbalance and colorectal cancer显示文摘The gut microbiota acts as a real organ. The symbiotic interactions between resident micro-organisms and the digestive tract highly contribute to maintain the gut homeostasis. However, alterations to the microbiome caused by environmental changes(e.g., infection, diet and/or lifestyle) can disturb this symbiotic relationship and promote disease, such as inflammatory bowel diseases and cancer. Colorectal cancer is a complex association of tumoral cells, non-neoplastic cells and a large amount of micro-organisms, and the involvement of the microbiota in colorectal carcinogenesis is becoming increasingly clear. Indeed, many changes in the bacterial composition of the gut microbiota have been reported in colorectal cancer, suggesting a major role of dysbiosis in colorectal carcinogenesis. Some bacterial species have been identified and suspected to play a role in colorectal carcinogenesis, such as Streptococcus bovis, Helicobacter pylori, Bacteroides fragilis, Enterococcus faecalis, Clostridium septicum, Fusobacterium spp. and Escherichia coli. The potential pro-carcinogenic effects of these bacteria are now better understood. In this review, we discuss the possible links between the bacterial microbiota and colorectal carcinogenesis, focusing on dysbiosis and the potential pro-carcinogenic properties of bacteria, such as genotoxicity and other virulence factors, inflammation, host defenses modulation, bacterial derived metabolism, oxidative stress and anti-oxidative defenses modulation. We lastly describe how bacterial microbiota modifications could represent novel prognosis markers and/or targets for innovative therapeutic strategies.Johan Gagnière Jennifer Raisch Julie Veziant Nicolas Barnich Richard Bonnet Emmanuel Buc Marie-Agnès Bringer Denis Pezet Mathilde Bonnet 2016World Journal of Gastroenterology2016,22,2:76
5Fecal microbiota transplantation broadening its application beyond intestinal disorders显示文摘Intestinal dysbiosis is now known to be a complication in a myriad of diseases.Fecal microbiota transplantation(FMT),as a microbiota-target therapy,is arguably very effective for curing Clostridium difficile infection and has good outcomes in other intestinal diseases.New insights have raised an interest in FMT for the management of extra-intestinal disorders associated with gut microbiota.This review shows that it is an exciting time in the burgeoning science of FMT application in previously unexpected areas,including metabolic diseases,neuropsychiatric disorders,autoimmune diseases,allergic disorders,and tumors.A randomized controlled trial was conducted on FMT in metabolic syndrome by infusing microbiota from lean donors or from self-collected feces,with the resultant findings showing that the lean donor feces group displayed increased insulin sensitivity,along with increased levels of butyrate-producing intestinal microbiota.Case reports of FMT have also shown favorable outcomes in Parkinson's disease,multiple sclerosis,myoclonus dystonia,chronic fatigue syndrome,and idiopathic thrombocytopenic purpura.FMT is a promising approach in the manipulation of the intestinal microbiota and has potential applications in a variety of extra-intestinal conditions associated with intestinal dysbiosis.Meng-Que Xu Hai-Long Cao Wei-Qiang Wang Shan Wang Xiao-Cang Cao Fang Yan Bang-Mao Wang 2015World Journal of Gastroenterology2015,21,1:63
6Gut microbiota role in irritable bowel syndrome:Newtherapeutic strategies显示文摘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.Eleonora Distrutti Lorenzo Monaldi Patrizia Ricci Stefano Fiorucci 2016World Journal of Gastroenterology2016,22,7:60
7An insoluble polysaccharide from the sclerotium of Poria cocos improves hyperglycemia, hyperlipidemia and hepatic steatosis in ob/ob mice via modulation of gut microbiota显示文摘Metabolic syndrome characterized by obesity, hyperglycemia and liver steatosis is becoming prevalent all over the world. Herein, a water insoluble polysaccharide(WIP) was isolated and identified from the sclerotium of Poria cocos, a widely used Traditional Chinese Medicine. WIP was confirmed to be a(1-3)-β-D-glucan with an average Mw of 4.486 × 10~6 Da by NMR and SEC-RI-MALLS analyses. Furthermore, oral treatment with WIP from P. cocos significantly improved glucose and lipid metabolism and alleviated hepatic steatosis in ob/ob mice. 16 S DNA sequencing analysis of cecum content from WIP-treated mice indicated the increase of butyrate-producing bacteria Lachnospiracea, Clostridium. It was also observed that WIP treatment elevated the level of butyrate in gut, improved the gut mucosal integrity and activated the intestinal PPAR-γ pathway. Fecal transplantation experiments definitely confirmed the causative role of gut microbiota in mediating the benefits of WIP. It is the first report that the water insoluble polysaccharide from the sclerotium of P. cocos modulates gut microbiota to improve hyperglycemia and hyperlipidemia. Thereby, WIP from P. cocos, as a prebiotic, has the potential for the prevention or cure of metabolic diseases and may elucidate new mechanism for the efficacies of this traditional herbal medicine on the regulation of lipid and glucose metabolism.SUN Shan-Shan WANG Kai MA Ke BAO Li LIU Hong-Wei 2019Chinese Journal of Natural Medicines2019,17,1:60
8Fecal microbiota transplantation as novel therapy in gastroenterology:A systematic review显示文摘AIM:To study the clinical efficacy and safety of Fecal microbiota transplantation(FMT).We systematically reviewed FMT used as clinical therapy.METHODS:We searched MEDLINE,EMBASE,the Cochrane Library and Conference proceedings from inception to July,2013.Treatment effect of FMT was calculated as the percentage of patients who achieved clinical improvement per patient category,on an intention-to-treat basis.RESULTS:We included 45 studies;34 on Clostridium difficile-infection(CDI),7 on inflammatory bowel disease,1 on metabolic syndrome,1 on constipation,1 on pouchitis and 1 on irritable bowel syndrome(IBS).In CDI 90% resolution of diarrhea in 33 case series(n = 867) was reported,and 94% resolution of diarrhea after repeated FMT in a randomized controlled trial(RCT)(n = 16).In ulcerative colitis(UC) remission rates of 0% to 68% were found(n = 106).In Crohn's disease(CD)(n = 6),no benefit was observed.In IBS,70% improvement of symptoms was found(n = 13).100% Reversal of symptoms was observed in constipation(n = 3).In pouchitis,none of the patients(n = 8) achieved remission.One RCT showed significant improvement of insulin sensitivity in metabolic syndrome(n = 10).Serious adverse events were rare.CONCLUSION:FMT is highly effective in CDI,and holds promise in UC.As for CD,chronic constipation,pouchitis and IBS data are too limited to draw conclusions.FMT increases insulin sensitivity in metabolic syndrome.Noortje G Rossen John K Mac Donald Elisabeth M de Vries Geert R D'Haens Willem M de Vos Erwin G Zoetendal Cyriel Y Ponsioen 2015World Journal of Gastroenterology2015,21,17:41
9Gut microbiota dysbiosis in patients with nonalcoholic fatty liver disease显示文摘BACKGROUND:Gut microbiota plays a significant role in the pathogenesis of non-alcoholic fatty liver disease(NAFLD)This study aimed to assess the contribution of gut microbiota dysbiosis to the pathogenesis of NAFLD.METHODS:Forty-seven human feces samples(25 NAFLD patients and 22 healthy subjects) were collected and 16 S r DNA amplicon sequencing was conducted on Hiseq 2000 platform Discrepancy of species composition between controls and NAFLD group was defined by Metastats analysis under P value<0.01.RESULTS:NAFLD patients harbored lower gut microbiota diversity than healthy subjects did.In comparison to the control group,the Proteobacteria(13.50%) and Fusobacteria(2.76%) phyla were more abundant in NAFLD patients.Additionally,the Lachnospiraceae(21.90%),Enterobacteriaceae(12.02%),Erysipelotrichaceae(3.83%),and Streptococcaceae(1.39%) families,as well as the Escherichia_Shigella(10.84%)Lachnospiraceae_Incertae_Sedis(7.79%),and Blautia(4.95%)genera were enriched in the NAFLD group.However,there was a lower abundance of Prevotella in the NAFLD group than that in the control group(5.83% vs 27.56%,P<0.01)The phylum Bacteroidetes(44.63%) also tended to be more abundant in healthy subjects,and the families Prevotellaceae(28.66%) and Ruminococcaceae(26.44%) followed the same trend.Compared to those without non-alcoholic steatohepatitis(NASH),patients with NASH had higher abundance of genus Blautia(5.82% vs 2.25%;P=0.01) and the corresponding Lachnospiraceae family(24.33% vs 14.21%;P<0.01).Patients with significant fibrosis had a higher abundance of genus Escherichia_Shigella(12.53% vs 1.97%;P<0.01) and the corresponding Enterobacteriaceae family(13.92% vs 2.07%;P<0.01) compared to those with F0/F1 fibrosis.CONCLUSIONS:NAFLD patients and healthy subjects harbor varying gut microbiota.In contrast to the results of previous research on children,decreased levels of Prevotella might be detrimental for adults with NAFLD.The increased level of the genus Blautia,the family Lachnospiraceae,the genus Escherichia_Shigella,and the family Enterobacteriaceae may be a primary contributor to NAFLD progression.Feng Shen Rui-Dan Zheng Xing-Qiang Sun Wen-Jin Ding Xiao-Ying Wang Jian-Gao Fan 2017Hepatobiliary & Pancreatic Diseases International2017,16,4:46
10Washed microbiota transplantation vs.manual fecal microbiota transplantation:clinical findings,animal studies and in vitro screening显示文摘Fecal microbiota transplantation(FMT)by manual preparation has been applied to treat diseases for thousands of years.However,this method still endures safety risks and challenges the psychological endurance and acceptance of doctors,patients and donors.Population evidence showed the washed microbiota preparation with microfiltration based on an automatic purification system followed by repeated centrifugation plus suspension for three times significantly reduced FMT-related adverse events.This washing preparation makes delivering a precise dose of the enriched microbiota feasible,instead of using the weight of stool.Intraperitoneal injection in mice with the fecal microbiota supernatant obtained after repeated centrifugation plus suspension for three times induced less toxic reaction than that by the first centrifugation following the microfiltration.The toxic reactions that include death,the change in the level of peripheral white blood cells,and the proliferation of germinal center in secondary lymphoid follicles in spleen were noted.The metagenomic next-generation sequencing(NGS)indicated the increasing types and amount of viruses could be washed out during the washing process.Metabolomics analysis indicated metabolites with pro-inflammatory effects in the fecal microbiota supernatant such as leukotriene B4,corticosterone,and prostaglandin G2 could be removed by repeated washing.Near-infrared absorption spectroscopy could be served as a rapid detection method to control the quality of the washingprocess.In conclusion,this study for the first time provides evidence linking clinical findings and animal experiments to support that washed microbiota transplantation(WMT)is safer,more precise and more quality-controllable than the crude FMT by manual.Ting Zhang Gaochen Lu Zhe Zhao Yafei Liu Quan Shen Pan Li Yaoyao Chen Haoran Yin Huiquan Wang Cicilia Marcella Bota Cui Lei Cheng Guozhong Ji Faming Zhang 2020Protein & Cell2020,11,4:44
11Gut microbiota and liver diseases显示文摘Several studies revealed that gut microbiota are associated with various human diseases,e.g.,metabolic diseases,allergies,gastroenterological diseases,and liver diseases.The liver can be greatly affected by changes in gut microbiota due to the entry of gut bacteria or their metabolites into the liver through the portal vein,and the liver-gut axis is important to understand the pathophysiology of several liver diseases,especially non-alcoholic fatty liver disease and hepatic encephalopathy.Moreover,gut microbiota play a significant role in the development of alcoholic liver disease and hepatocarcinogenesis.Based on theseprevious findings,trials using probiotics have been performed for the prevention or treatment of liver diseases.In this review,we summarize the current understanding of the changes in gut microbiota associated with various liver diseases,and we describe the therapeutic trials of probiotics for those diseases.Masami Minemura Yukihiro Shimizu 2015World Journal of Gastroenterology2015,21,6:41
12Gut microbiota and host metabolism in liver cirrhosis显示文摘The gut microbiota has the capacity to produce a diverse range of compounds that play a major role in regulatingthe activity of distal organs and the liver is strategically positioned downstream of the gut. Gut microbiota linked compounds such as short chain fatty acids, bile acids, choline metabolites, indole derivatives, vitamins, polyamines, lipids, neurotransmitters and neuroactive compounds, and hypothalamic-pituitary-adrenal axis hormones have many biological functions. This review focuses on the gut microbiota and host metabolism in liver cirrhosis. Dysbiosis in liver cirrhosis causes serious complications, such as bacteremia and hepatic encephalopathy, accompanied by small intestinal bacterial overgrowth and increased intestinal permeability. Gut dysbiosis in cirrhosis and intervention with probiotics and synbiotics in a clinical setting is reviewed and evaluated. Recent studies have revealed the relationship between gut microbiota and host metabolism in chronic metabolic liver disease, especially, non-alcoholic fatty liver disease, alcoholic liver disease, and with the gut microbiota metabolic interactions in dysbiosis related metabolic diseases such as diabetes and obesity. Recently, our understanding of the relationship between the gut and liver and how this regulates systemic metabolic changes in liver cirrhosis has increased. The serum lipid levels of phospholipids, free fatty acids, polyunsaturated fatty acids, especially, eicosapentaenoic acid, arachidonic acid, and docosahexaenoic acid have significant correlations with specific fecal flora in liver cirrhosis. Many clinical and experimental reports support the relationship between fatty acid metabolism and gut-microbiota. Various blood metabolome such as cytokines, amino acids, and vitamins are correlated with gut microbiota in probioticstreated liver cirrhosis patients. The future evaluation of the gut-microbiota-liver metabolic network and the intervention of these relationships using probiotics, synbiotics, and prebiotics, with sufficient nutrition could aid the development of treatments and prevention for liver cirrhosis patients.Makoto Usami Makoto Miyoshi Hayato Yamashita 2015World Journal of Gastroenterology2015,21,41:44
13Strategies to modulate the intestinal microbiota and their effects on nutrient utilization, performance, and health of poultry显示文摘Poultry is widely produced and consumed meat globally.Its demand is expected to continue increasing to meet the animal protein requirement for ever-increasing human population.Thus,the challenge that poultry scientists and industry face are to produce sufficient amount of poultry meat in the most efficient way.In the past,using antibiotics to promote the growth of poultry and manage gut microbiota was a norm.However,due to concerns over potential fatalistic impacts on food animals and indirectly to humans,their use as feed additives are banned or regulated in several jurisdictions.In this changed context,several alternative strategies have been proposed with some success that mimics the functions of antibiotics as growth promoters and modulate gut microbiota for their beneficial roles.These include the use of probiotics,prebiotics,organic acids,and exogenous enzyme,among others.Gut microbiota and their metabolic products improve nutrient digestion,absorption,metabolism,and overall health and growth performance of poultry.This paper reviews the available information on the effect of feed additives used to modulate intestinal microbiota of poultry and their effects on overall health and growth performance.Understanding these functions and interactions will help to develop new dietary and managerial strategies that will ultimately lead to enhanced feed utilization and improved growth performance of poultry.This review will help future researchers and industry to identify alternative feed ingredients having properties like prebiotics,probiotics,organic acids,and exogenous enzymes.Sudhir Yadav Rajesh Jha 2019Journal of Animal Science and Biotechnology2019,10,3:37
14Intestinal microbiota in pathophysiology and management of irritable bowel syndrome显示文摘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.Kang Nyeong Lee Oh Young Lee 2014World Journal of Gastroenterology2014,20,27:35
15Helicobacter pylori vs coronary heart disease-searching for connections显示文摘In this review,we discussed the findings and concepts underlying the potential role of Helicobacter pylori(H.pylori) infections in the initiation,development or persistence of atherosclerosis and coronary heart disease(CHD).This Gram-negative bacterium was described by Marshall and Warren in 1984.The majority of infected subjects carries and transmits H.pylori with no symptoms; however,in some individuals these bacteria may cause peptic ulcers,and even gastric cancers.The widespread prevalence of H.pylori infections and the fact that frequently they remain asymptomatic may suggest that,similarly to intestinal microflora,H.pylori may deliver antigens that stimulate not only local,but also systemic inflammatory response.Recently,possible association between H.pylori infection and extragastric disorders has been suggested.Knowledge on the etiology of atherosclerosis together with current findings in the area of H.pylori infections constitute the background for the newly proposed hypothesis that those two processes may be related.Many research studies confirm the indirect association between the prevalence of H.pylori and the occurrence of CHD.According to majority of findings the involvement of H.pylori in this process is based on the chronic inflammation which might facilitate the CHDrelated pathologies.It needs to be elucidated,if the infection initiates or just accelerates the formation of atheromatous plaque.Magdalena Chmiela Adrian Gajewski Karolina Rudnicka 2015World Journal of Cardiology2015,7,4:33
16Intestinal microbiota in health and disease: Role of bifidobacteria in gut homeostasis显示文摘The pool of microbes inhabiting our body is known as 'microbiota' and their collective genomes as 'microbiome'. The colon is the most densely populated organ in the human body, although other parts, such as the skin, vaginal mucosa, or respiratory tract, also harbour specific microbiota. This microbial community regulates some important metabolic and physiological functions of the host, and drives the maturation of the immune system in early life, contributing to its homeostasis during life. Alterations of the intestinal microbiota can occur by changes in composition(dysbiosis), function, or microbiota-host interactions and they can be directly correlated with several diseases. The only disease in which a clear causal role of a dysbiotic microbiota has been demonstrated is the case of Clostridium difficile infections. Nonetheless, alterations in composition and function of the microbiota have been associated with several gastrointestinal diseases(inflammatory bowel disease, colorectal cancer, or irritable bowel syndrome), as well as extra-intestinal pathologies, such as those affecting the liver, or the respiratory tract(e.g., allergy, bronchial asthma, and cystic fibrosis), among others. Species of Bifidobacterium genus are the normal inhabitants of a healthy human gut and alterations in number and composition of their populations is one of the most frequent features present in these diseases. The use of probiotics, including bifidobacteria strains, in preventive medicine to maintain a healthy intestinal function is well documented. Probiotics are also proposed as therapeutic agents for gastrointestinal disorders and other pathologies. The World Gastroenterology Organization recently published potential clinical applications for several probiotic formulations, in which species of lactobacilli are predominant. This review is focused on probiotic preparations containing Bifidobacterium strains, alone or in combination with other bacteria, which have been tested in human clinical studies. In spite of extensive literature on and research into this topic, the degree of scientific evidence of the effectiveness of probiotics is still insufficient in most cases. More effort need to be made to design and conduct accurate human studies demonstrating the efficacy of probiotics in the prevention, alleviation, or treatment of different pathologies.Rafael Tojo Adolfo Suárez Marta G Clemente Clara G de los Reyes-Gavilán Abelardo Margolles Miguel Gueimonde Patricia Ruas-Madiedo 2014World Journal of Gastroenterology2014,20,41:33
17Ablation of gut microbiota alleviates obesity-induced hepatic steatosis and glucose intolerance by modulating bile acid metabolism in hamsters显示文摘Since metabolic process differs between humans and mice, studies were performed in hamsters, which are generally considered to be a more appropriate animal model for studies of obesityrelated metabolic disorders. The modulation of gut microbiota, bile acids and the farnesoid X receptor(FXR) axis is correlated with obesity-induced insulin resistance and hepatic steatosis in mice. However,the interactions among the gut microbiota, bile acids and FXR in metabolic disorders remained largely unexplored in hamsters. In the current study, hamsters fed a 60% high-fat diet(HFD) were administeredvehicle or an antibiotic cocktail by gavage twice a week for four weeks. Antibiotic treatment alleviated HFD-induced glucose intolerance, hepatic steatosis and inflammation accompanied with decreased hepatic lipogenesis and elevated thermogenesis in subcutaneous white adipose tissue(sWAT). In the livers of antibiotic-treated hamsters, cytochrome P450 family 7 subfamily B member 1(CYP7 B1) in the alternative bile acid synthesis pathway was upregulated, contributing to a more hydrophilic bile acid profile with increased tauro-β-muricholic acid(TβMCA). The intestinal FXR signaling was suppressed but remained unchanged in the liver. This study is of potential translational significance in determining the role of gut microbiota-mediated bile acid metabolism in modulating diet-induced glucose intolerance and hepatic steatosis in the hamster.Lulu Sun Yuanyuan Pang Xuemei Wang Qing Wu Huiying Liu Bo Liu George Liu Min Ye Wei Kong Changtao Jiang 2019Acta Pharmaceutica Sinica B2019,9,4:29
18Intestinal microbiota pathogenesis and fecal microbiota transplantation for inflammatory bowel disease显示文摘The intestinal microbiota plays an important role in inflammatory bowel disease(IBD).The pathogenesis of IBD involves inappropriate ongoing activation of the mucosal immune system driven by abnormal intestinal microbiota in genetically predisposed individuals.However,there are still no definitive microbial pathogens linked to the onset of IBD.The composition and function of the intestinal microbiota and their metabolites are indeed disturbed in IBD patients.The special alterations of gut microbiota associated with IBD remain to be evaluated.The microbial interactions and hostmicrobe immune interactions are still not clarified.Limitations of present probiotic products in IBD are mainly due to modest clinical efficacy,few available strains and no standardized administration.Fecal microbiota transplantation(FMT)may restore intestinal microbial ho-meostasis,and preliminary data have shown the clinical efficacy of FMT on refractory IBD or IBD combined with Clostridium difficile infection.Additionally,synthetic microbiota transplantation with the defined composition of fecal microbiota is also a promising therapeutic approach for IBD.However,FMT-related barriers,including the mechanism of restoring gut microbiota,standardized donor screening,fecal material preparation and administration,and long-term safety should be resolved.The role of intestinal microbiota and FMT in IBD should be further investigated by metagenomic and metatranscriptomic analyses combined with germfree/human flora-associated animals and chemostat gut models.Zi-Kai Wang Yun-Sheng Yang Ye Chen Jing Yuan Gang Sun Li-Hua Peng 2014World Journal of Gastroenterology2014,20,40:30
19Obesity, fatty liver disease and intestinal microbiota显示文摘Nonalcoholic fatty liver disease(NAFLD) is a chronic liver disorder that is increasing in prevalence with the worldwide epidemic of obesity. NAFLD is the hepatic manifestation of the metabolic syndrome. The term NAFLD describes a spectrum of liver pathology ranges from simple steatosis to steatosis with inflammation nonalcoholic steatohepatitis and even cirrhosis. Metabolic syndrome and NAFLD also predict hepatocellular carcinoma. Many genetic and environmental factors have been suggested to contribute to the development of obesity and NAFLD, but the exact mechanisms are not known. Intestinal ecosystem contains trillions of microorganisms including bacteria, Archaea, yeasts and viruses. Several studies support the relationship between the intestinal microbial changes and obesity and also its complications, including insulin resistance and NAFLD. Given that the gut and liver are connected by the portal venous system, it makes the liver more vulnerable to translocation of bacteria, bacterial products, endotoxins or secreted cytokines. Altered intestinal microbiota(dysbiosis) may stimulate hepatic fat deposition through several mechanisms: regulation of gut permeability, increasing low-grade inflammation, modulation of dietary choline metabolism, regulation of bile acid metabolism and producing endogenous ethanol. Regulation of intestinal microbial ecosystem by diet modifications or by using probiotics and prebiotics as a treatment for obesity and its complications might be the issue of further investigations.Nur Arslan 2014World Journal of Gastroenterology2014,20,44:30
20Alteration of the esophageal microbiota in Barrett's esophagus and esophageal adenocarcinoma显示文摘The incidence of esophageal adenocarcinoma(EAC) has increased in recent decades, and its 5-year survival rate is less than 20%. As a well-established precursor, patients with Barrett's esophagus(BE) have a persistent risk of progression to EAC. Many researchers have already identified some factors that may contribute to the development of BE and EAC, and the identified risks include gastroesophageal reflux(GER), male sex, older age, central obesity,tobacco smoking, Helicobacter pylori(H. pylori) eradication, and the administration of proton pump inhibitors(PPIs) and antibiotics. The human gut harbors trillions of microorganisms, the majority of which are bacteria. These microorganisms benefit the human host in many ways, such as helping in digestion, assisting in the synthesis of certain vitamins, promoting the development of the gastrointestinal immune system, regulating metabolism and preventing invasion by specific pathogens. In contrast, microbial dysbiosis may play important roles in various diseases, such as inflammation and cancers. The composition of the microbiota located in the normal esophagus is relatively conserved without distinct microbial preferences in the upper, middle and lower esophagus. Six major phyla constitute the esophageal microbiota, including Firmicutes,Bacteroides, Actinobacteria, Proteobacteria, Fusobacteria and TM7, similar to the oral microbiota. Streptococcus dominates the esophageal microbiota. However, the microbiota varies in different esophageal diseases compared to that in the healthy esophagus. The type Ⅰ microbiota, which is primarily composed of gram-positive bacteria, is closely associated with the normal esophagus, while type Ⅱ microbiota has enriched gram-negative bacteria and is mainly associated with the abnormal esophagus. These increased gram-negative anaerobes/microaerophiles include Veillonella, Prevotella, Haemophilus, Neisseria, Granulicatella and Fusobacterium, many of which are associated with BE. The microbial diversity in the esophagus is decreased in EAC patients, and Lactobacillus fermentum is enriched compared to that in controls and BE patients. Furthermore, the microbiota may be associated with BE and EAC by interacting with their risk factors, including central obesity, GER, H. pylori, administration of PPIs and antibiotics. Therefore, a large gap in research must be bridged to elucidate the associations among these factors. Some studies have already proposed several potential mechanisms by which the microbiota participates in human carcinogenesis by complicated interactions with the human host immune system and signaling pathways. The activation of the LPS-TLR4-NF-κB pathway may contribute to inflammation and malignant transformation. This exciting field of gastrointestinal microbiota allows us to unravel the mystery of carcinogenesis from another perspective. Further studies are needed to explore whether the microbiota changes before or after disease onset, to improve our understanding of the pathogenesis, and to find novel targets for prevention, diagnosis and therapy, which could offer more cost-effective and relatively safe choices.Jing Lv Lei Guo Ji-Jun Liu He-Ping Zhao Jun Zhang Ji-Han Wang 2019World Journal of Gastroenterology2019,25,18:27
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