Alzheimer＇s disease （AD） is a most common neurodegenerative disorder, which associates with impaired cognition. Gut microbiota can modulate host brain function and behavior via microbiota-gut-brain axis, including ...Alzheimer＇s disease （AD） is a most common neurodegenerative disorder, which associates with impaired cognition. Gut microbiota can modulate host brain function and behavior via microbiota-gut-brain axis, including cognitive behavior. Germ-free animals, antibiotics, probiotics intervention and diet can induce alterations of gut microbiota and gut physiology and also host cognitive behavior, increasing or decreasing risks of AD. The increased permeability of intestine and blood-brain barrier induced by gut rnicrobiota disturbance will increase the incidence of neurodegeneration disorders. Gut microbial metabolites and their effects on host neurochemical changes may increase or decrease the risk of AD. Pathogenic microbes infection will also increase the risk of AD, and meanwhile, the onset of AD support the ＂hygiene hypothesis＂. All the results suggest that AD may begin in the gut, and is closely related to the imbalance of gut microbiota. Modulation of gut microbiota through personalized diet or beneficial microbiota intervention will probably become a new treatment for AD.展开更多
Metagenomic approaches are currently being used to decipher the genome of the microbiota(microbiome),and,in parallel,functional studies are being performed to analyze the effects of the microbiota on the host.Gnotobio...Metagenomic approaches are currently being used to decipher the genome of the microbiota(microbiome),and,in parallel,functional studies are being performed to analyze the effects of the microbiota on the host.Gnotobiological methods are an indispensable tool for studying the consequences of bacterial colonization.Animals used as models of human diseases can be maintained in sterile conditions(isolators used for germ-free rearing)and specifically colonized with defined microbes(including non-cultivable commensal bacteria).The effects of the germ-free state or the effects of colonization on disease initiation and maintenance can be observed in these models.Using this approach we demonstrated direct involvement of components of the microbiota in chronic intestinal inflammation and development of colonic neoplasia(i.e.,using models of human inflammatory bowel disease and colorectal carcinoma).In contrast,a protective effect of microbiota colonization was demonstrated for the development of autoimmune diabetes in non-obese diabetic(NOD)mice.Interestingly,the development of atherosclerosis in germ-free apolipoprotein E(ApoE)-deficient mice fed by a standard low-cholesterol diet is accelerated compared with conventionally reared animals.Mucosal induction of tolerance to allergen Bet v1 was not influenced by the presence or absence of microbiota.Identification of components of the microbiota and elucidation of the molecular mechanisms of their action in inducing pathological changes or exerting beneficial,disease-protective activities could aid in our ability to influence the composition of the microbiota and to find bacterial strains and components(e.g.,probiotics and prebiotics)whose administration may aid in disease prevention and treatment.展开更多
The hygiene hypothesis is thought to be a significant contributor to the growing incidence of inflammatory bowel disease (IBD) around the world, although the evidence for specific factors that underlie the hygiene hyp...The hygiene hypothesis is thought to be a significant contributor to the growing incidence of inflammatory bowel disease (IBD) around the world, although the evidence for specific factors that underlie the hygiene hypothesis in IBD is unclear. We aimed to systematically review the literature to determine which hygiene-related factors are associated with the development of IBD. Publications identified from a broad based MEDLINE and Current Contents search between 1966 and 2007 on key terms relevant to the 'hygiene hypothesis' and IBD including H pylori exposure, helminths, cold chain hypothesis, measles infection and vaccination, antibiotic use, breastfeeding, family size, sibship, urban upbringing, day care attendance and domestic hygiene were reviewed. The literature suggests that the hygiene hypothesis and its association with decreased microbial exposure in childhood probably plays an important role in the development of IBD, although the strength of the supporting data for each of the factors varies considerably. The most promising factors that may potentially be associated with development of IBD include H pylori exposure, helminths, breastfeeding and sibship. However, the vast majority of studies in this area are plagued by serious methodological shortcomings, particularly the reliance on retrospective recall of information making it difficult to truly ascertain the importance of a 'hygiene hypothesis' in IBD. The 'hygiene hypothesis' in IBD is an important area of research that may give clues to the aetiology of this disease. Directions for future research are recommended.展开更多
文摘Alzheimer＇s disease （AD） is a most common neurodegenerative disorder, which associates with impaired cognition. Gut microbiota can modulate host brain function and behavior via microbiota-gut-brain axis, including cognitive behavior. Germ-free animals, antibiotics, probiotics intervention and diet can induce alterations of gut microbiota and gut physiology and also host cognitive behavior, increasing or decreasing risks of AD. The increased permeability of intestine and blood-brain barrier induced by gut rnicrobiota disturbance will increase the incidence of neurodegeneration disorders. Gut microbial metabolites and their effects on host neurochemical changes may increase or decrease the risk of AD. Pathogenic microbes infection will also increase the risk of AD, and meanwhile, the onset of AD support the ＂hygiene hypothesis＂. All the results suggest that AD may begin in the gut, and is closely related to the imbalance of gut microbiota. Modulation of gut microbiota through personalized diet or beneficial microbiota intervention will probably become a new treatment for AD.
基金grants from the Czech Science Foundation(nos.303/08/0367,303/09/0449,310/07/014,305/08/0535,310/09/1640 and 310/08/H077)the Grant Agency of the Academy of Sciences of the Czech Republic(nos.IAA500200910,IAA500200710,KJB500200904,IAA500200917 and A500200709)+3 种基金the Ministry of Education,Youth and Sports of the Czech Republic(nos.2B06053,2B06155 and MSM 0021620812)the Ministry of Health of the Czech Republic(nos.NS/9775-4,NS/10054-3 and NS/10340-3)EU Project Marie Curie CT 215553,EU Project IPODD consortium(202020)the Institutional Research Concept AV0Z50200510.
文摘Metagenomic approaches are currently being used to decipher the genome of the microbiota(microbiome),and,in parallel,functional studies are being performed to analyze the effects of the microbiota on the host.Gnotobiological methods are an indispensable tool for studying the consequences of bacterial colonization.Animals used as models of human diseases can be maintained in sterile conditions(isolators used for germ-free rearing)and specifically colonized with defined microbes(including non-cultivable commensal bacteria).The effects of the germ-free state or the effects of colonization on disease initiation and maintenance can be observed in these models.Using this approach we demonstrated direct involvement of components of the microbiota in chronic intestinal inflammation and development of colonic neoplasia(i.e.,using models of human inflammatory bowel disease and colorectal carcinoma).In contrast,a protective effect of microbiota colonization was demonstrated for the development of autoimmune diabetes in non-obese diabetic(NOD)mice.Interestingly,the development of atherosclerosis in germ-free apolipoprotein E(ApoE)-deficient mice fed by a standard low-cholesterol diet is accelerated compared with conventionally reared animals.Mucosal induction of tolerance to allergen Bet v1 was not influenced by the presence or absence of microbiota.Identification of components of the microbiota and elucidation of the molecular mechanisms of their action in inducing pathological changes or exerting beneficial,disease-protective activities could aid in our ability to influence the composition of the microbiota and to find bacterial strains and components(e.g.,probiotics and prebiotics)whose administration may aid in disease prevention and treatment.
文摘The hygiene hypothesis is thought to be a significant contributor to the growing incidence of inflammatory bowel disease (IBD) around the world, although the evidence for specific factors that underlie the hygiene hypothesis in IBD is unclear. We aimed to systematically review the literature to determine which hygiene-related factors are associated with the development of IBD. Publications identified from a broad based MEDLINE and Current Contents search between 1966 and 2007 on key terms relevant to the 'hygiene hypothesis' and IBD including H pylori exposure, helminths, cold chain hypothesis, measles infection and vaccination, antibiotic use, breastfeeding, family size, sibship, urban upbringing, day care attendance and domestic hygiene were reviewed. The literature suggests that the hygiene hypothesis and its association with decreased microbial exposure in childhood probably plays an important role in the development of IBD, although the strength of the supporting data for each of the factors varies considerably. The most promising factors that may potentially be associated with development of IBD include H pylori exposure, helminths, breastfeeding and sibship. However, the vast majority of studies in this area are plagued by serious methodological shortcomings, particularly the reliance on retrospective recall of information making it difficult to truly ascertain the importance of a 'hygiene hypothesis' in IBD. The 'hygiene hypothesis' in IBD is an important area of research that may give clues to the aetiology of this disease. Directions for future research are recommended.
