Sleep apnoea, gut dysbiosis and cognitive dysfunction

Sleep disorders are becoming increasingly common, and their distinct effects on physical and mental health require elaborate investigation. Gut dysbiosis (GD) has been reported in sleep-related disorders, but sleep apnoea is of particular significance because of its higher prevalence and chronicity. Cumulative evidence has suggested a link between sleep apnoea and GD. This review highlights the gut-brain communication axis that is mediated via commensal microbes and various microbiota-derived metabolites (e.g. short-chain fatty acids, lipopolysaccharide and trimethyl amine N-oxide), neurotransmitters (e.g. gamma-aminobutyric acid, serotonin, glutamate and dopamine), immune cells and inflammatory mediators, as well as the vagus nerve and hypothalamic-pituitary-adrenal axis. This review also discusses the pathological role underpinning GD and altered gut bacterial populations in sleep apnoea and its related comorbid conditions, particularly cognitive dysfunction. In addition, the review examines the preclinical and clinical evidence, which suggests that prebiotics and probiotics may potentially be beneficial in sleep apnoea and its comorbidities through restoration of eubiosis or gut microbial homeostasis that regulates neural, metabolic and immune responses, as well as physiological barrier integrity via the gut-brain axis. Emerging evidence suggests a critical link between gut microbiota and host health homeostasis. Obstructive sleep apnoea exerts detrimental effects on the gut microenvironment, which aggravates cognitive impairment via microbial-derived metabolites, neurotransmitters and an altered immune response. The restoration of eubiosis in obstructive sleep apnoea can be effectively achieved using continuous positive airway pressure. Lifestyle modifications, notably the supplementation of prebiotics and probiotics, are also recommended.image

Automated summary

Sleep disorders have significant effects on physical and mental health, and there is a link between gut dysbiosis and sleep apnoea. The gut-brain communication axis, involving commensal microbes, microbiota-derived metabolites, neurotransmitters, immune cells, and inflammatory mediators, is important in this relationship. Restoring gut microbial homeostasis may have potential benefits for sleep apnoea and its comorbidities.