The innervated gut and critical illness.

PURPOSE OF REVIEW: This review highlights brain-gut neuroimmune interactions in the context of critical illness. Neural regulation of inflammation, gut innervation, and the brain-gut axis in critical illness are discussed.

RECENT FINDINGS: Recent studies indicate that the brain-gut axis and the enteric nervous system are integral to the regulation of local and systemic inflammation. Experimental evidence suggests that neural reflexes control immune responses, and specific neural signals promote gastrointestinal homeostasis. The understanding of these interactions in the clinical context remains limited, necessitating further investigation. Notably, therapeutic interventions targeting neuro-immune pathways have shown promise in preclinical models, suggesting that a better understanding of the neuro-immune crosstalk in the critically ill may potentially identify novel therapeutic targets.

SUMMARY: Critical illness involves complex organ dysfunction, not least in the gastrointestinal system. A multitude of neuroimmune interactions between the intestinal wall, immune cells, peripheral nerves and the central nervous system regulate inflammation. While experimental evidence supports the role of neural reflexes in controlling immune responses, clinical validation is lacking in the context of critical care. Future research needs to explore whether specific neural signals or mechanisms of neuro-immune crosstalk can be harnessed to restore and support gastrointestinal homeostasis in the critically ill.