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Brain Research Aug 2018The gut microbiota - the trillions of bacteria that reside within the gastrointestinal tract - has been found to not only be an essential component immune and metabolic... (Review)
Review
The gut microbiota - the trillions of bacteria that reside within the gastrointestinal tract - has been found to not only be an essential component immune and metabolic health, but also seems to influence development and diseases of the enteric and central nervous system, including motility disorders, behavioral disorders, neurodegenerative disease, cerebrovascular accidents, and neuroimmune-mediated disorders. By leveraging animal models, several different pathways of communication have been identified along the "gut-brain-axis" including those driven by the immune system, the vagus nerve, or by modulation of neuroactive compounds by the microbiota. Of the latter, bacteria have been shown to produce and/or consume a wide range of mammalian neurotransmitters, including dopamine, norepinephrine, serotonin, or gamma-aminobutyric acid (GABA). Accumulating evidence in animals suggests that manipulation of these neurotransmitters by bacteria may have an impact in host physiology, and preliminary human studies are showing that microbiota-based interventions can also alter neurotransmitter levels. Nonetheless, substantially more work is required to determine whether microbiota-mediated manipulation of human neurotransmission has any physiological implications, and if so, how it may be leveraged therapeutically. In this review this exciting route of communication along the gut-brain-axis, and accompanying data, are discussed.
Topics: Animals; Brain; Gastrointestinal Microbiome; Humans; Neurotransmitter Agents
PubMed: 29903615
DOI: 10.1016/j.brainres.2018.03.015 -
Gut Aug 2020The human gut microbiome is a complex ecosystem that can mediate the interaction of the human host with their environment. The interaction between gut microbes and... (Review)
Review
The human gut microbiome is a complex ecosystem that can mediate the interaction of the human host with their environment. The interaction between gut microbes and commonly used non-antibiotic drugs is complex and bidirectional: gut microbiome composition can be influenced by drugs, but, vice versa, the gut microbiome can also influence an individual's response to a drug by enzymatically transforming the drug's structure and altering its bioavailability, bioactivity or toxicity (pharmacomicrobiomics). The gut microbiome can also indirectly impact an individual's response to immunotherapy in cancer treatment. In this review we discuss the bidirectional interactions between microbes and drugs, describe the changes in gut microbiota induced by commonly used non-antibiotic drugs, and their potential clinical consequences and summarise how the microbiome impacts drug effectiveness and its role in immunotherapy. Understanding how the microbiome metabolises drugs and reduces treatment efficacy will unlock the possibility of modulating the gut microbiome to improve treatment.
Topics: Animals; Antineoplastic Agents, Immunological; Drug-Related Side Effects and Adverse Reactions; Gastrointestinal Microbiome; Humans; Hypoglycemic Agents; Immune Checkpoint Inhibitors; Immune System Phenomena; Metformin; Pharmaceutical Preparations; Pharmacology; Proton Pump Inhibitors
PubMed: 32409589
DOI: 10.1136/gutjnl-2019-320204 -
Frontiers in Cellular and Infection... 2019Probiotics have been used to treat a variety of diseases for decades; however, what is the rationale for their application? Such a treatment was first proposed in the... (Review)
Review
Probiotics have been used to treat a variety of diseases for decades; however, what is the rationale for their application? Such a treatment was first proposed in the early nineteenth century based on observations of decreased bifidobacterial populations in children suffering from diarrhea, suggesting that oral intake of bifidobacteria could replete this subpopulation of the microbiota and improve health. Since then, studies have shown modifications in the gut or skin microbiota in the course of a variety of diseases and suggested positive effects of certain probiotics. Most studies failed to report any impact on the microbiota. The impact of probiotics as well as of bacteria colonizing food does not reside in their ability to graft in the microbiota but rather in sharing genes and metabolites, supporting challenged microbiota, and directly influencing epithelial and immune cells. Such observations argue that probiotics could be associated with conventional drugs for insulin resistance, infectious diseases, inflammatory diseases, and psychiatric disorders and could also interfere with drug metabolism. Nevertheless, in the context of a plethora of probiotic strains and associations produced in conditions that do not allow direct comparisons, it remains difficult to know whether a patient would benefit from taking a particular probiotic. In other words, although several mechanisms are observed when studying a single probiotic strain, not all individual strains are expected to share the same effects. To clarify the role of probiotics in the clinic, we explored the relation between probiotics and the gut and skin microbiota.
Topics: Animals; Anti-Bacterial Agents; Bacteria; Bifidobacterium; Child; Diarrhea; Drug Interactions; Drug Resistance, Bacterial; Gastrointestinal Microbiome; Humans; Probiotics; Psychiatry; Psychopathology
PubMed: 32010640
DOI: 10.3389/fcimb.2019.00454 -
Gastroenterologia Y Hepatologia 2021The human body is populated by myriads of microorganisms throughout its surface and in the cavities connected to the outside. The microbial colonisers of the intestine... (Review)
Review
The human body is populated by myriads of microorganisms throughout its surface and in the cavities connected to the outside. The microbial colonisers of the intestine (microbiota) are a functional and non-expendable part of the human organism: they provide genes (microbiome) and additional functions to the resources of our species and participate in multiple physiological processes (somatic development, nutrition, immunity, etc.). Some chronic non-communicable diseases of developed society (atopias, metabolic syndrome, inflammatory diseases, cancer and some behaviour disorders) are associated with dysbiosis: loss of species richness in the intestinal microbiota and deviation from the ancestral microbial environment. Changes in the vertical transmission of the microbiome, the use of antiseptics and antibiotics, and dietary habits in industrialised society appear to be at the origin of dysbiosis. Generating and maintaining diversity in the microbiota is a new clinical target for health promotion and disease prevention.
Topics: Gastrointestinal Microbiome; Humans; Immune System; Neurosecretory Systems
PubMed: 33652061
DOI: 10.1016/j.gastrohep.2021.01.009 -
Nutrients Jul 2020As an imbalance in the intestinal microbiota can lead to the development of several diseases (e.g., type 1 diabetes, cancer, among others), the use of prebiotics,... (Review)
Review
As an imbalance in the intestinal microbiota can lead to the development of several diseases (e.g., type 1 diabetes, cancer, among others), the use of prebiotics, probiotics, and postbiotics to alter the gut microbiome has attracted recent interest. Postbiotics include any substance released by or produced through the metabolic activity of the microorganism, which exerts a beneficial effect on the host, directly or indirectly. As postbiotics do not contain live microorganisms, the risks associated with their intake are minimized. Here, we provided a critical review of postbiotics described in the literature, including their mechanisms of action, clinical characteristics, and potential therapeutic applications. We detailed the pleiotropic effects of postbiotics, including their immunomodulatory, anti-inflammatory, antioxidant, and anti-cancer properties. Although the use of postbiotics is an attractive strategy for altering the microbiome, further study into its efficacy and safety is warranted.
Topics: Animals; Antitubercular Agents; Autophagy; Bacteria; Diet; Enzymes; Fatty Acids; Gastrointestinal Microbiome; Humans; Immunologic Factors; Inflammation; Polysaccharides; Prebiotics; Probiotics; Wound Healing
PubMed: 32717965
DOI: 10.3390/nu12082189 -
Chinese Medical Journal Oct 2016To systematically review the updated information about the gut microbiota-brain axis. (Review)
Review
OBJECTIVE
To systematically review the updated information about the gut microbiota-brain axis.
DATA SOURCES
All articles about gut microbiota-brain axis published up to July 18, 2016, were identified through a literature search on PubMed, ScienceDirect, and Web of Science, with the keywords of "gut microbiota", "gut-brain axis", and "neuroscience".
STUDY SELECTION
All relevant articles on gut microbiota and gut-brain axis were included and carefully reviewed, with no limitation of study design.
RESULTS
It is well-recognized that gut microbiota affects the brain's physiological, behavioral, and cognitive functions although its precise mechanism has not yet been fully understood. Gut microbiota-brain axis may include gut microbiota and their metabolic products, enteric nervous system, sympathetic and parasympathetic branches within the autonomic nervous system, neural-immune system, neuroendocrine system, and central nervous system. Moreover, there may be five communication routes between gut microbiota and brain, including the gut-brain's neural network, neuroendocrine-hypothalamic-pituitary-adrenal axis, gut immune system, some neurotransmitters and neural regulators synthesized by gut bacteria, and barrier paths including intestinal mucosal barrier and blood-brain barrier. The microbiome is used to define the composition and functional characteristics of gut microbiota, and metagenomics is an appropriate technique to characterize gut microbiota.
CONCLUSIONS
Gut microbiota-brain axis refers to a bidirectional information network between the gut microbiota and the brain, which may provide a new way to protect the brain in the near future.
Topics: Animals; Brain; Central Nervous System; Gastrointestinal Microbiome; Gastrointestinal Tract; Humans; Hypothalamo-Hypophyseal System; Pituitary-Adrenal System
PubMed: 27647198
DOI: 10.4103/0366-6999.190667 -
Current Biology : CB Mar 2022All animals, from cnidarians to humans, are colonized with microbes, and the greatest diversity and magnitude of these host-associated microorganisms resides within the...
All animals, from cnidarians to humans, are colonized with microbes, and the greatest diversity and magnitude of these host-associated microorganisms resides within the intestine. Referred to as the gut microbiome, membership can be as simple as one species of bacteria or can be composed of hundreds to thousands of different microbes across the domains of life. The relationship between the gut microbiome and host span from beneficial to detrimental; interactions may be context-dependent and occur across host physiology and organ systems. In this Primer, we focus on the mammalian host to discuss basic mechanisms by which the gut microbiome impacts the host and review mechanisms by which hosts and the environment shape the microbiome. We end by highlighting key concepts and discussing future directions for the field that will be critical for generating the next generation of knowledge of the gut microbiome.
Topics: Animals; Bacteria; Gastrointestinal Microbiome; Mammals; Microbiota
PubMed: 35349808
DOI: 10.1016/j.cub.2022.02.023 -
Nature Reviews. Gastroenterology &... Feb 2022Although bacteriophages have been overshadowed as therapeutic agents by antibiotics for decades, the emergence of multidrug-resistant bacteria and a better understanding... (Review)
Review
Although bacteriophages have been overshadowed as therapeutic agents by antibiotics for decades, the emergence of multidrug-resistant bacteria and a better understanding of the role of the gut microbiota in human health and disease have brought them back into focus. In this Perspective, we briefly introduce basic phage biology and summarize recent discoveries about phages in relation to their role in the gut microbiota and gastrointestinal diseases, such as inflammatory bowel disease and chronic liver disease. In addition, we review preclinical studies and clinical trials of phage therapy for enteric disease and explore current challenges and potential future directions.
Topics: Bacteriophages; Gastrointestinal Diseases; Gastrointestinal Microbiome; Humans
PubMed: 34782783
DOI: 10.1038/s41575-021-00536-z -
Gastroenterology Jan 2021Inflammatory bowel diseases (IBD) develop via convergence of environmental, microbial, immunological, and genetic factors. Alterations in the gut microbiota have been... (Review)
Review
Inflammatory bowel diseases (IBD) develop via convergence of environmental, microbial, immunological, and genetic factors. Alterations in the gut microbiota have been associated with development and progression of IBD, but it is not clear which populations of microbes are involved or how they might contribute to IBD. We review the genetic and environmental factors affecting the gut microbiota, the roles of gut microbes and their bioproducts in the development and clinical course of IBD, and strategies by which microbiome-based therapies can be used to prevent, manage, and eventually cure IBD. We discuss research findings that help bridge the gap between the basic sciences and clinical application.
Topics: Animals; Diet; Disease Models, Animal; Dysbiosis; Fecal Microbiota Transplantation; Gastrointestinal Microbiome; Humans; Inflammatory Bowel Diseases; Mice; Prebiotics; Probiotics
PubMed: 33253681
DOI: 10.1053/j.gastro.2020.09.056 -
Trends in Molecular Medicine Jun 2016The gut microbiota is a key player in many physiological and pathological processes occurring in humans. Recent investigations suggest that the efficacy of some clinical... (Review)
Review
The gut microbiota is a key player in many physiological and pathological processes occurring in humans. Recent investigations suggest that the efficacy of some clinical approaches depends on the action of commensal bacteria. Antibiotics are invaluable weapons to fight infectious diseases. However, by altering the composition and functions of the microbiota, they can also produce long-lasting deleterious effects for the host. The emergence of multidrug-resistant pathogens raises concerns about the common, and at times inappropriate, use of antimicrobial agents. Here we review the most recently discovered connections between host pathophysiology, microbiota, and antibiotics highlighting technological platforms, mechanistic insights, and clinical strategies to enhance resistance to diseases by preserving the beneficial functions of the microbiota.
Topics: Animals; Anti-Bacterial Agents; Bacteria; Cell Line; Drug Resistance, Bacterial; Gastrointestinal Microbiome; Humans; Immune System; Mice
PubMed: 27178527
DOI: 10.1016/j.molmed.2016.04.003