Microbiome—The Missing Link in the Gut-Brain Axis: Focus on Its Role in Gastrointestinal and Mental Health

Abstract

The central nervous system (CNS) and the human gastrointestinal (GI) tract communicate through the gut-brain axis (GBA). Such communication is bi-directional and involves neuronal, endocrine, and immunological mechanisms. There is mounting data that gut microbiota is the source of a number of neuroactive and immunocompetent substances, which shape the structure and function of brain regions involved in the control of emotions, cognition, and physical activity. Most GI diseases are associated with altered transmission within the GBA that are influenced by both genetic and environmental factors. Current treatment protocols for GI and non-GI disorders may positively or adversely affect the composition of intestinal microbiota with a diverse impact on therapeutic outcome(s). Alterations of gut microbiota have been associated with mood and depressive disorders. Moreover, mental health is frequently affected in GI and non-GI diseases. Deregulation of the GBA may constitute a grip point for the development of diagnostic tools and personalized microbiota-based therapy. For example, next generation sequencing (NGS) offers detailed analysis of microbiome footprints in patients with mental and GI disorders. Elucidating the role of stem cell–host microbiome cross talks in tissues in GBA disorders might lead to the development of next generation diagnostics and therapeutics. Psychobiotics are a new class of beneficial bacteria with documented efficacy for the treatment of GBA disorders. Novel therapies interfering with small molecules involved in adult stem cell trafficking are on the horizon.

Crosstalk Between the Gut Microbiome and Bioactive Lipids: Therapeutic Targets in Cognitive Frailty

“…Host health and longevity are also influenced by a plethora of other intricate processes, networks, and cellular signaling mechanisms, including intestinal barrier permeability, elevated production of microbe metabolites (e.g., short-chain fatty acids), and an increase in gut peptides (3,16,39,40). Notably, lipidsa diverse group of organic biomolecules-are essential elements in gut permeability as the major constituents of cell membranes and hence, in the modulation of the gut microbiome (41).…”

Salmonella Strain Specificity Determines Post-typhoid Central Nervous System Complications: Intervention by Lactiplantibacillus plantarum at Gut-Brain Axis

“…Many gastro-intestinal conditions are associated with mental health abnormalities such as depression, anxiety, and mood disorders and occur due to disturbances in the gut-brain axis (Skonieczna-Żydecka et al, 2018). The ability of probiotics in restoring the delicate balance between these two, serves as a potential treatment alternative in the present scenario and therefore have been renamed as "psychobiotics" (Dinan et al, 2013).…”

Isoproterenol Disrupts Intestinal Barriers Activating Gut-Liver-Axis: Effects on Intestinal Mucus and Vascular Barrier as Entry Sites

“…However, besides this "in-to-outside" movement, here we address vice versa the concept of "out-to-inside" with increased accessibility of the vascular compartment to molecules normally being closed out. In fact, in the presence of a disrupted GVB, this con-cept per se is currently proposed to be the pathophysiological culprit of multiple liver diseases (non-and/or alcoholic liver disease, cirrhosis and complications, primary sclerosis cholangitis, hepatocellular carcinoma) but also contributing to systemic diseases including obesity, diabetes mellitus and central-nervous pathologies via fuelling the gut-liver [5] and gut-brain-axis [31]. In addition, the gut-liver axis has been demonstrated to contribute to liver injury and potentially liver failure in septic conditions [32].…”