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
