Gut Microbiome-Brain Communications Regulate Host Physiology and Behavior

Abstract

cell injury [6], metabolic regulation [7], GI tract development [8], innate and adaptive immune responses, and absorption of nutrients [9,10]. Alterations in microbiota composition and dysregulation of the intestinal mucosa homeostasis have been implicated in the development and progression of pathologies. This compositional change in the microbiota and/ or an abnormality in the interactions between the host and the commensal microbiota is referred to as dysbiosis. Gut microbiota dysbiosis has been linked to chronic low-grade intestinal inflammation and acute intestinal autoimmunity diseases such as Irritable Bowel Syndrome (IBS) and Inflammatory Bowel Disease (IBD) [11,12]. Abnormal microbiota composition is associated with a wide range of metabolic and behavioral disorders, such as anxiety/depression [13][14][15] [26]. GI microbiota dysbiosis might also be involved in the development and persistence of systemic disorders [27]. For example, obesity has been characterized by a decrease in overall diversity [28] and an increase in Proteobacteria abundance and in the Firmicutes to Bacteroidetes ratio [28,29] and microbiota composition is believed to influence energy balance and glucose homeostasis [30][31][32].Evidence that changes in microbiota composition are correlated with metabolic and behavioral disorders has drawn attention to a potential causal role for the microbiota in pathologies and has led to the emergence of the 'microbiota-gutbrain axis' concept [33][34][35]. The gut-brain axis is a bidirectional communication system between the GI tract and the brain [36] via hormonal, immunological, and neural signaling. Information from the GI tract and the intestinal microbiota can reach the peripheral and Central Nervous System (CNS), concurrently the brain is able to influence GI functions such as motility and secretion but also immune responses and cytokine production [36,37]. The Microbiota-Gut-Brain AxisThe gut microbiota can modulate gut-brain axis signaling via direct and indirect mechanisms. The microbiota acts via endocrine, metabolic (bacterial components and metabolites), AbstractThe human gut microbiota contains more than 100 trillion bacteria that, under normal physiological conditions, have beneficial symbiotic interactions with the host. However, a growing body of evidence has shown that alternations in the composition and diversity of the gut microbiota, or dysbiosis, can influence the development and progress of metabolic and neurological disorders. Communication between the microbiota and the brain is a bidirectional system involving endocrine, metabolic (bacterial components and metabolites), immune, and neural pathways. Gut microbiota composition influences the signals transmitted from the gut to the brain. Alternatively, the brain utilizes similar mechanisms, in particular endocrine and neural signaling, to modulate the composition of the gut bacteria. In this review, we describe the recent evidence of gut microbiota interaction with the central nervous system to influence physiological a...

2′-Fucosyllactose Supplementation Improves Gut-Brain Signaling and Diet-Induced Obese Phenotype and Changes the Gut Microbiota in High Fat-Fed Mice

“…Accumulating evidence suggests the gut microbiota plays a crucial role in the development of obesity [3,4]. Under normal physiological conditions, the gut microbiota has symbiotic interactions with the host, conferring beneficial effects on host physiology and behavior [5]. However, compositional and functional alterations of the gut microbiota, i.e., dysbiosis, induced by lifestyle factors have been implicated in the development and progression of metabolic disturbances including obesity as well as other pleotropic physiologic effects [6].…”

Beneficial Effects of Non-Encapsulated or Encapsulated Probiotic Supplementation on Microbiota Composition, Intestinal Barrier Functions, Inflammatory Profiles, and Glucose Tolerance in High Fat Fed Rats

“…They can inhibit the growth of pathogenic bacteria such as Clostridium perfringens and/or promote the proliferation of beneficial populations such as Bifidobacteria [12]. Probiotics inhibits the growth of enteric pathogens via the production of inhibitory antimicrobials, competitively adhering to the mucosa and epithelium, strengthening the epithelial barrier integrity via mucin and defensins, and modulating the immune system of the host [13]. Furthermore, probiotic-driven changes in gut microbiota can lead to changes in the production of intestinal short chain fatty acids (SCFAs) [14], promoting the production of GI peptides, including glucagon-like peptide-1 (GLP-1) [15].…”

Good or bad: gut bacteria in human health and diseases

“…More and more evidence shows that changes in the composition and diversity of the gut microbiota have a substantial influence on the pathology of CNS disorders, and consequently there has been a growing attention to microbiota-based therapeutics, including probiotics, prebiotics and faecal microbiota transplants [65]. For example, recent studies demonstrate treatment with Bacteroides fragilis corrects levels of tight junction proteins and cytokines in mice neurological symptoms related to autism spectrum disorder (ASD) [66][67][68].…”