Gut microbiota dysbiosis: The potential mechanisms by which alcohol disrupts gut and brain functions

Abstract

Alcohol use disorder (AUD) is a high-risk psychiatric disorder and a key cause of death and disability in individuals. In the development of AUD, there is a connection known as the microbiota-gut-brain axis, where alcohol use disrupts the gut barrier, resulting in changes in intestinal permeability as well as the gut microbiota composition, which in turn impairs brain function and worsens the patient’s mental status and gut activity. Potential mechanisms are explored by which alcohol alters gut and brain function through the effects of the gut microbiota and their metabolites on immune and inflammatory pathways. Alcohol and microbiota dysregulation regulating neurotransmitter release, including DA, 5-HT, and GABA, are also discussed. Thus, based on the above discussion, it is possible to speculate on the gut microbiota as an underlying target for the treatment of diseases associated with alcohol addiction. This review will focus more on how alcohol and gut microbiota affect the structure and function of the gut and brain, specific changes in the composition of the gut microbiota, and some measures to mitigate the changes caused by alcohol exposure. This leads to a potential intervention for alcohol addiction through fecal microbiota transplantation, which could normalize the disruption of gut microbiota after AUD.

Gut bacteria exacerbates TNBS-induced colitis and kidney injury through oxidative stress

“…We speculated that lipopolysaccharides (LPS), a large molecule in the outer membrane of gram-negative bacteria, could be involved. This thinking is supported by the fact that TNBS used for induction of colitis was dissolved in 50% ethanol, whereas ethanol has been reported to be able to increase serum LPS level derived from intestinal Gram-negative bacteria [ 34 ]. Indeed, TNBS-induced colitis was reported to be associated with a high level of serum LPS [ [26] , [27] , [28] ].…”

Gut microbiome in alcohol use disorder: Implications for health outcomes and therapeutic strategies-a literature review

“…Although the exact mechanism has not yet been characterized, alcohol may lead to gut inflammation via alterations in the gut microbiota by promoting an increase in pro-inflammatory bacteria and/or decrease in anti-inflammatory bacteria, and affecting cytokine expression. Accordingly, in an animal model treated with human gut microbiota, the relative population of a pro-inflammatory bacterium (Clostridium cluster XIVa) increased, whereas there was a decrease in anti-inflammatory bacteria ( Akkermansia muciniphila , Atopobium, Faecalibacterium prausnitzii ), compared to untreated[ 37 ]. Interestingly, this kind of alcohol-induced dysbiosis was found to mediate intestinal barrier dysfunction, as well as ALD, via activation of tumor necrosis factor receptor I, in intestinal epithelial cells.…”

Chronic alcohol consumption and COVID‐19 infection risk: A narrative review

“…Chronic alcohol consumption and AUD cause tremendous changes in microbiota composition, leading to increased proinflammatory microbiome and gut leakage (Chen et al, 2022;Engen et al, 2015).…”

“…Chronic alcohol consumption and AUD cause tremendous changes in microbiota composition, leading to increased proinflammatory microbiome and gut leakage (Chen et al, 2022; Engen et al, 2015). Additionally, gut permeability and the resulting inflammation have an impact on neurotransmitter expression in the brain, therefore supporting the development and maintenance of AUD (Bajo et al, 2014; Qamar et al, 2019).…”