Effects of Low-Intensity Pulsed Ultrasound on the Gut-Brain Axis.

The gut-brain axis is a bidirectional communication network involved in inflammatory, metabolic, and neurobehavioural homeostasis. Low-intensity pulsed ultrasound (LIPUS) is a non-invasive biophysical modality that may influence this axis through acoustic mechanotransduction and downstream changes in inflammatory signalling, epithelial barrier function, microbial ecology, and neuroimmune activity. This mini review synthesizes predominantly preclinical evidence on abdominal and brain-directed LIPUS. Current rodent studies indicate that abdominal stimulation can produce coordinated intestinal, systemic, microbial, and central responses, whereas brain-directed stimulation can be accompanied by improvement in both cerebral inflammation and intestinal pathology. Mechanistic studies outside the gut-brain axis further suggest that mechanosensitive ion channels, focal-adhesion signalling, cytoskeletal remodelling, NF-κB, and inflammasome-related pathways may connect acoustic forces to biological responses. However, no single study has established the complete causal sequence from acoustic stimulation to gut-brain communication. Direct human evidence for LIPUS efficacy in gut-brain axis-related disorders is currently lacking. LIPUS should therefore be regarded as a promising preclinical approach requiring standardized acoustic reporting, independent replication, causal pathway validation, and disease-specific optimization before clinical translation.