Probiotics And The Gut Microbiota In Intestinal Health And Disease Pdf
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- Intestinal microbiota in human health and disease: the impact of probiotics
- Targeting gut flora to treat and prevent disease
- Gut Flora: In the Treatment of Disease
- Gut Microbiota Status in COVID-19: An Unrecognized Player?
Intestinal microbiota in human health and disease: the impact of probiotics
Gut flora is the largest reservoir of human flora. It is an essential factor in certain pathological disorders, including multisystem organ failure, colon cancer and inflammatory bowel diseases and extraintestinal disorders, such as allergy, asthma and even obesity. Prebiotics and probiotics are known to have a role in prevention or treatment of some diseases.
Nevertheless, bacteria have been found to be useful for treating disease and thus promoting human health in a safe and natural way. The endogenous gastrointestinal microbial flora plays a fundamentally important role in normal health and disease [ 1 ].
According to recent advances in microbiome research, the infectious, inflammatory and functional bowel diseases are closely associated with the pathologic changes in gut microbiota.
Recent discovery of the fact that disbalance of gut microbiome has a profound impact on the function of the liver through microbiota liver axis [ 2 ]. There has been a re-emergence of interest in the relationship between gastrointestinal flora and gut function with the recognition that prebiotics, probiotics and other means of modifying gut flora may function as therapeutic modalities.
The human intestine is colonized by millions of bacteria, primarily anaerobic bacteria, comprising approximately species. The intestinal flora includes Bifidobacteria, Lactobacillus, Propionobacteria, Peptostreptococci and Enterococci.
The commensal flora produces antibiotic-like substances that are anti-fungal, anti-viral and reduce pH near the wall of the gut forming a protective barrier, which is uninhabitable for the pathogenic bacteria to colonize [ 3 ]. In a healthy person, their numbers are limited and controlled by commensal flora.
The flora which enters the body through food and drink constitutes the transitional flora. In a healthy gut microbiome, it does not cause disease however any harm to the commensal flora will enable them to cause the disease. Indiscriminate use of antibiotics not only makes the problem of antibiotic resistant bacterial strains even worse, but also kills many commensal bacteria that promote homeostasis and protect against carcinogenesis.
It has been seen that changes in the bacterial community occur in the gut microbiome of colon cancer patients, with tumors harboring increased bacterial diversity and an abundance of pathogenic bacteria compared to surrounding healthy tissue [ 4 ]. Lactobacillus and Bifidobacteria are known to prevent tumor formation by suppressing the growth factors like MyD88 an adaptor molecule necessary for most toll-like receptors TLR signaling was found to be essential in the development of the carcinomas [ 5 , 6 ].
A number of in vitro and animal studies provide evidence that consuming probiotics suppresses colon rectal cancer. These studies have also proposed multiple pathways by which probiotics could inhibit colon cancer by influencing innate immune pathways and apoptosis, reducing oxidative stress and modulating intestinal bacteria and their metabolism [ 7 ].
Lactobacillus johnsonii reduced the concentration of Enterobacters and modulated immune response in colon rectal cancer patients, whereas Bifidobacterium longum did not have any effect. In another study, L. However, these clinical trials are limited by the small number of subjects and their short duration [ 8 ].
Mice experimentally colonized with Helicobacter hepaticus and enterotoxigenic Bacteroides fragilis exhibit colonic Th17 inflammatory infiltrates that appear to have a beneficial role in human ovarian cancer [ 9 ], murine melanoma, pancreatic and colon cancer [ 10 — 12 ]. Fecal microbiota transplantations FMT are effective in maintaining a healthy gut microbiome particularly in patients with severe Clostridium difficile infections. A recent study transplanted a culture of six phylogenetically diverse gut microbes into mice.
With C. Probiotics are live microorganisms present in foods as dietary supplement that confer a health benefit. Lactobacilli in yoghurt improved digestion of dairy products in individuals who are lactose intolerant [ 15 ].
Probiotics can be improved upon by supplementing food with bacteria engineered to have more beneficial effect. Oral administration of a strain of Lactobacillus acidophilus having phosphoglycerol transferase gene deleted to APC floxed mice resulted in the reduction in polyps [ 16 ].
A protein elafin produced by engineered strains of Lactobacillus casie and Lactococcus lactis diminished inflammation in a mouse model of colitis [ 17 ]. Another example is a strain of Lactobacillus gasseri , which was engineered to overexpress the antioxidant superoxide dismutase and decreased colitis in interleukin IL knockout mice [ 18 ].
The introduction of genetically engineered organisms to produce and deliver cytokines or other biologically relevant molecules to the mucosa offers further potential to the probiotics. Prebiotics are the non-digestible food ingredient that beneficially affects the host by stimulating the growth or activity of a genus of bacteria.
A number of prebiotics have been implicated in cancer prevention [ 19 ]. Prebiotics include dietary fiber sources such as inulin that promote the growth of bifidobacteria. Dietary polyphenols include flavonoids, phenolic acids, lignins present in tea, wine, fruits, nuts and vegetables.
Ellagic acid is polyphenol present in certain berries and nuts that is an antioxidant with cancer preventive properties [ 20 ]. Epidemiological studies have reported correlations between equol or equol-producing bacteria and diminished breast cancer risk in women and diminished prostate cancer in men in Asian populations [ 21 ]. However, further studies are needed to determine whether probiotics can be used as protective agents for the prevention of human colon cancer.
It is possible that a microbiota favoring commensal bacteria could alter the immune response to tumors at extraintestinal as well as intestinal sites. Bacterial species isolated from inflammatory bowel disease IBD patients have shown to be capable of inducing intestinal inflammation e. Intestinal inflammation was seen in germ-free SCID mice colonized with individual or combinations of strains of Enterococcus faecalis, Fusobacterium mortiferum, Bacteroides distasonis and segmented filamentous bacteria SFB [ 22 ].
Because of the potentially harmful role of these bacteria, antibiotics are frequently prescribed to treat IBD [ 25 ]. A probiotic nonpathogenic strain of E. More recently, a probiotic product called VSL 3 which is a combination of eight probiotics: Bifidobacterium breve, B. The results of fecal microbiota transplantation FMT show very promising but discrepant results.
A meta-analysis recently conducted by Colman et al. A recently conducted randomized trial in patients with ulcerative colitis showed that the clinical remission was not statistically significant with FMT due to small study numbers but in all the responders a shift in the microbiota composition was observed supporting the role of microbiota manipulation in the treatment of IBD [ 31 , 32 ]. Novel treatment strategies for IBD and celiac disease are being developed using parasitic nematodes particularly Trichuris spp.
Studies of the impact of parasite colonization on the human gut microbiota have shed light on the potential role of the gut microbiota in whipworm-mediated suppression of inflammation. The therapeutic ability of T. A significant decrease in the bacterial phylum cyanobacteria accompanied by an expansion of Bacteroidetes and Tenericutes was seen in Trichuris-infected ICD macques. In another study, the administration of a single dose of T. Another study involving experimental infection with Heligmosomoides polygyrus bakeri in a mouse model of IBD revealed a significant expansion of the bacterial family Lactobacillaceae in the ileum of infected mice, which correlated with disease outcome [ 37 ].
While heavy burdens of hookworm parasites are associated with pathological effects, experimental infections with small numbers of N. A pilot study done to explore the impact of experimental infections with N. A higher species richness of the gut microbiota has been associated with healthier homeostasis.
Allergic disease development has been associated with alterations in the intestinal microbiota. Infants with food allergies were found to exhibit lower lactobacilli and bifidobacteria species while coliforms and Staphylococcus aureus were higher [ 40 ]. Bifidobacteria was decreased while increase in clostridia was found in infants with atopic dermatitis [ 41 ].
Administration of L. A number of studies have been performed using probiotics to treat the severity of various allergic diseases, including atopic eczema, atopic dermatitis and food allergy in these children [ 43 , 44 ]. Oral administration of optimal combinations of probiotic Lactobacilli and Bifidobacteria in murine models is able to reduce allergic diseases. This could be due to lower Th2 cytokine secretion on innate exposure [ 45 , 46 ]. Environmental exposures in early infancy are thus a deciding factor of the composition of gut microbiota which decides the development of immune function in an individual.
These differences in immune function link to the development of allergy and asthma [ 47 ]. A possible interpretation is that the bacteria ingested or inhaled served as a kind of tolerance inducing adjuvant for allergens ingested or inhaled as reported recently that commensal bacteria protect against food allergen sensitization [ 48 ].
The bacteria associated with protection were largely members of the Bacteriodetes and Firmicutes phyla e. Several associations exist between commensal microbiota and the development of allergic diseases.
In prospective studies, early fecal samples of infants who go on to develop allergies, compared to those who remain healthy, grew less Enterococci, Bifidobacteria, Bacteroides, Clostridia and Staphylococci [ 49 ]. Japanese infants developing early allergy have different bifidobacteria spp compared to nonallergic infants [ 50 ].
In an experimental animal model of food allergy, the gut microbiota and its stimulatory action on innate immune system by toll-like receptors TLR , particularly TLR4, have been found. Mice susceptible to food allergies have a mutation in TLR4 blocking its signaling [ 51 ].
Probiotics have been suggested to act by reducing the permeability of intestine [ 52 ]. They can interact with the host immune system and modify the natural course of allergic disease [ 53 ].
Recent data indicate that probiotics could modulate the production of cytokines by monocytes and lymphocytes [ 54 ]. The dendritic cells may be stimulated by probiotic bacteria in the intestinal lumen and express TLR-2 and inflammatory cytokines [ 55 ]. Therefore, the stimulation of innate immunity may be the cause of the observed inflammatory signs and beneficial clinical effects.
The microbes occupying the human gut are in direct relation to obesity. The obese have more Firmicutes and fewer Bacteroidetes. The more Bacteroidetes, the more weight loss by an obese person [ 56 ]. An opportunistic pathogen isolated from the gut of obese human causing obesity in germ-free mice has been identified [ 57 ]. Housing mice with obese microbiota with those of lean microbiota suppresses the obesity factor in the former mice [ 58 ].
These data indicate clearly that microbiota can influence metabolic parameters or even obesity [ 59 , 60 ]. The intestinal flora of obese individuals has been suggested to undergo changes that would increase the extraction of calories from nutrients.
An animal study, using germ-free mice observed that these mice despite ingesting greater amounts of food than conventionally raised mice, presented a lower amount of body fat [ 61 ].
Another study has shown that obese mice had a reduced number of Bacteroides and a proportional increase in Firmicutes when compared to lean mice [ 62 ]. They also proposed that flora of obese mice favored a greater capacity of extracting calories from food, as the feces of these mice were observed to have less calories and a greater amount of fermentation end products.
A correlation between obesity and intestinal flora has been proposed in type 2 diabetes. The inflammation that leads to diabetes in obesity has been proposed to be triggered by LPS of Gram-negative bacteria, which compose the intestinal flora [ 63 ].
Also it has been seen that in humans, individuals with type 2 diabetes presented lower levels of serum lipopolysaccharide than patients with type 2 diabetes by age [ 64 ].
Also in animal studies, it has been seen that mice treated with a high fat diet were observed to present a reduction in intestinal permeability and in serum LPS levels, in addition to a decrease in inflammation of adipose tissue and macrophage infiltration, after the modification of gut flora by antibiotics [ 65 ].
The endogenous gastrointestinal flora plays a fundamentally important role in health and disease. The characterization of this diverse ecosystem fuelled by the recognition of the potential value of probiotics and other means of modifying gut flora can be used as future therapeutic modalities.
It may hence be possible to establish profiles of the microbiota in humans based on the bacterial species composition of the enterotypes [ 66 ]. Licensee IntechOpen. This chapter is distributed under the terms of the Creative Commons Attribution 3. Help us write another book on this subject and reach those readers.
Targeting gut flora to treat and prevent disease
Gut flora is the largest reservoir of human flora. It is an essential factor in certain pathological disorders, including multisystem organ failure, colon cancer and inflammatory bowel diseases and extraintestinal disorders, such as allergy, asthma and even obesity. Prebiotics and probiotics are known to have a role in prevention or treatment of some diseases. Nevertheless, bacteria have been found to be useful for treating disease and thus promoting human health in a safe and natural way. The endogenous gastrointestinal microbial flora plays a fundamentally important role in normal health and disease [ 1 ]. According to recent advances in microbiome research, the infectious, inflammatory and functional bowel diseases are closely associated with the pathologic changes in gut microbiota. Recent discovery of the fact that disbalance of gut microbiome has a profound impact on the function of the liver through microbiota liver axis [ 2 ].
New titles:. Related titles:. For institutional orders, please contact sales wageningenacademic. Recommend this book to a librarian. Editors Pamela D. Browne , Eric Claassen and Michael D. Published online: July 14,
PDF | Gut microbiota is the community of live microorganisms residing in the digestive tract. the studies presented at the Digestive Diseases Week in San. Diego Various studies with probiotics have shown an.
Gut Flora: In the Treatment of Disease
A Good-quality patient-oriented evidence B Inconsistent or limited-quality patient-oriented evidence C Consensus, usual practice, opinion, disease-oriented evidence, case series. Over the past 6 months she has started taking a fiber supplement, drinking more water, and looking for links between stress and her symptoms. She has read about probiotics and wonders if you would consider recommending them in her situation. He is motivated to change his diet and has started to exercise more.
Gut Microbiota Status in COVID-19: An Unrecognized Player?
Probiotics are microbial strains that are beneficial to health, and their potential has recently led to a significant increase in research interest in their use to modulate the gut microbiota. The animal gut is a complex ecosystem of host cells, microbiota, and available nutrients, and the microbiota prevents several degenerative diseases in humans and animals via immunomodulation. The gut microbiota and its influence on human nutrition, metabolism, physiology, and immunity are addressed, and several probiotic species and strains are discussed to improve the understanding of modulation of gut microbiota. This paper provides a broad review of several Lactobacillus spp.
It seems that you're in Germany. We have a dedicated site for Germany. This book shows the huge impact the gut microbiota has on the gastrointestinal health of humans with a particular focus on children. Humans are not single organisms: We are a multi-organism structure composed of ourselves and our microbiota, living in close symbiosis since birth and even before. The huge impact that the billons of microscopic cells living in our gut have on our gastrointestinal and systemic health cannot be overestimated.
A meta-analysis has found that probiotics reduced the frequency of acute diarrhea in C. difficile-infected patients. S. boulardii, but not the Gram-.
The complex communities of microorganisms that colonise the human gastrointestinal tract play an important role in human health. The development of culture-independent molecular techniques has provided new insights in the composition and diversity of the intestinal microbiota. Here, we summarise the present state of the art on the intestinal microbiota with specific attention for the application of high-throughput functional microbiomic approaches to determine the contribution of the intestinal microbiota to human health. Moreover, we review the association between dysbiosis of the microbiota and both intestinal and extra-intestinal diseases. Finally, we discuss the potential of probiotic microorganism to modulate the intestinal microbiota and thereby contribute to health and well-being.
Its pages are open to the members of the Association, as well as to all members of the medical community interested in using this forum to publish their articles in accordance with the journal editorial policies. The principal aim of the journal is to publish original work in the broad field of Gastroenterology, as well as to provide information on the specialty and related areas that is up-to-date and relevant. The scientific works include the areas of Clinical, Endoscopic, Surgical, and Pediatric Gastroenterology, along with related disciplines.