Microbiota of the gastrointestinal tract: Friend or foe?

Abstract

The gut microbiota is currently considered an external organ of the human body that provides important mechanisms of metabolic regulation and protection. The gut microbiota encodes over 3 million genes, which is approximately 150 times more than the total number of genes present in the human genome. Changes in the qualitative and quantitative composition of the microbiome lead to disruption in the synthesis of key bacterial metabolites, changes in intestinal barrier function, and inflammation and can cause the development of a wide variety of diseases, such as diabetes, obesity, gastrointestinal disorders, cardiovascular issues, neurological disorders and oncological concerns. In this review, I consider issues related to the role of the microbiome in the regulation of intestinal barrier function, its influence on physiological and pathological processes occurring in the body, and potential new therapeutic strategies aimed at restoring the gut microbiome. Herewith, it is important to understand that the gut microbiota and human body should be considered as a single biological system, where change of one element will inevitably affect its other components. Thus, the study of the impact of the intestinal microbiota on health should be considered only taking into account numerous factors, the role of which has not yet been fully elucidated.

Recent advances in acid sensing by G protein coupled receptors

“…An intriguing feature of the GI tract is that its pH milieu changes from oral to aboral and from its lumen through the mucosal layer [ 4 ], with the largest variability observed in the small and large intestine, where pH values can range between pH 5 and pH 8 [ 34 ]. The intestinal pH is influenced by its microbiota [ 75 ], which in term is affected by lifestyle choices, disease burden and genetic factors of an individual [ 62 ]. A role for pHRs in inflammatory bowel diseases is well established [ 23 , 25 , 100 ], and the past few years have seen several papers investigating a role for TDAG8 in GI function.…”

The Impact of Early-Life Cecal Microbiota Transplantation on Social Stress and Injurious Behaviors in Egg-Laying Chickens

“…The gut microbiota is functionally like an endocrine organ, releasing numerous bioactive factors to activate the HPA and SAM stress systems in response to stimulations, consequently affecting host physiological and behavioral homeostasis via the bidirectional communication of the MGB and MGI axes [ 63 , 64 ]. Healthy intestinal microbial communities and functions are essential for animals to fit their living environments [ 132 , 133 ]. The intestinal microbial community has been named the “social or behavioral immune system” linked to the microbiota–gut–brain–immune axis [ 134 ] based on the two reciprocal themes: (1) that gut microbiota influences host social behavior and (2) that social behavior and social structure shape the composition of the gut microbiota across individuals [ 135 ].…”

Immune Cells, Gut Microbiota, and Vaccines: A Gender Perspective

“…Through the expression of more than 3 million genes, the gut microbiota (GM) plays a pivotal role in physiological mechanisms. Conversely, its deregulation has been linked to pathological processes affecting several organs and apparatuses [ 91 ]. The GM composition is the result of an intense interplay between genetic and environmental factors, such as age, sex, perinatal feeding, dietary habits, lifestyle and antibiotic exposure [ 92 ].…”