Functional gastrointestinal disorders and gut-brain axis: What does the future hold?

Abstract

Despite their high prevalence, lack of understanding of the exact pathophysiology of the functional gastrointestinal disorders has restricted us to symptomatic diagnostic tools and therapies. Complex mechanisms underlying the disturbances in the bidirectional communication between the gastrointestinal tract and the brain have a vital role in the pathogenesis and are key to our understanding of the disease phenomenon. Although we have come a long way in our understanding of these complex disorders with the help of studies on animals especially rodents, there need to be more studies in humans, especially to identify the therapeutic targets. This review study looks at the anatomical features of the gut-brain axis in order to discuss the different factors and underlying molecular mechanisms that may have a role in the pathogenesis of functional gastrointestinal disorders. These molecules and their receptors can be targeted in future for further studies and possible therapeutic interventions. The article also discusses the potential role of artificial intelligence and machine learning and its possible role in our understanding of these scientifically challenging disorders.

Keywords: Artificial intelligence; Functional gastrointestinal disorders; Gut-brain axis; Idiopathic bowel syndrome; Machine learning; Microbiome-gut-brain axis.

Figure 1

The biopsychosocial model for functional gastrointestinal disorder. The figure illustrates the interaction of psychosocial factors, environmental factors and disturbances in gut-brain axis with functional GI disorders. Early life stress events combined with psychosocial state of an individual determines the symptomatology and quality of life of individuals. Adopted from ROME IV[1].

Figure 2

Schematic representation of different factors modulating the gut-brain axis. The microbiota and central nervous system interact in a bidirectional relationship bridged by the gut-brain axis. This axis is also influenced by Immune system, enteric nervous system, hypothalamic-pituitary axis, and vagus nerve. CNS: Central nervous system; ENS: Enteric nervous system; HPA: Hypothalamic-pituitary.

Figure 3

The pathways involved in emotional response. The thalamo-amygdala pathway is responsible for unconditioned fast response without the input from the cortex. The thalamo-cortico amygdala pathway provides input for a complex, conditioned response due to input from the cerebral cortex.