Abstract Background Low-Intensity Pulsed Ultrasound (LIPUS) is a non-thermal mechanical energy modality that is currently exert promising results for its notably anti-inflammatory and regenerative effects on various tissues. However, its potential impact on inflamed mucosal tissue remains poorly explored. This study aims to investigate the use of LIPUS as an innovative biophysical therapeutic approach for the treatment of Inflammatory Bowel Disease (IBD). Methods Single and repeated, precisely targeted LIPUS stimulations (38 kHz, 150 mW/cm², 180 s) were applied under deep anesthesia to a 1 cm² mucosal area of 20 adults female C57BL/6 mice to assess its effect during early and late phases of DSS-induced colitis. Biological effects of LIPUS were characterized with multiple analyses, as reported in Figure 1. Extracellular vesicles (EVs) isolated from the plasma of LIPUS-treated mice (n = 10) were intravenously transferred at a concentration of 2.8 × 108 EV/mL into recipient colitic mice (n = 10) to evaluate their functional impact. Data were analyzed using un/paired t-test and two-way ANOVA. Results Single LIPUS stimulation was more effective, than closely spaced repeated stimulations, in improving clinical and macroscopic features of treated mice compared to controls, as assessed by evaluation of body weight, disease activity index, and colon length. At 2-, 24-, and 96-hours post-stimulation, a significant reduction in pro-inflammatory cytokines (TNF-α, IL-1β, IFN-γ) was observed (significant P 0.05). Furthermore, LIPUS significantly reduced immune cell infiltration (CD45+), promoted macrophage M2 phenotype switching (CD68+/CD163+), and accelerated restoration of barrier function, 2h post treatment. LIPUS-induced EVs, isolated at the same time point (2h post), injected into recipient mice, were able to decrease circulating TNF-α systemic levels. Conclusion Our findings demonstrate that LIPUS is a safe and effective biophysical approach capable of modulating inflammatory response and promoting tissue repair in experimental colitis. The positive mechanical effect of a single stimulation is detectable 2h post treatment and persists during the early recovery phase. In this study we provide initial preliminary data that need further confirmations regarding the mechanism which underlines this therapeutic effect. Despite that, LIPUS induced EVs, may represent one of the drivers of this systemic improvement, through the transfer of anti-inflammatory signals. Taken together, these results highlight the potential of LIPUS as a novel gut-targeted physical therapy and support future investigations regarding its application as translational strategy for modulating intestinal inflammation in IBD. Conflict of interest: Mrs. Ricchi, Benedetta: No conflict of interest Pineda Chavez, Samuel Elias: No conflict of interest Wozny, Marek: No conflict of interest Mori, Giada: No conflict of interest Pratellesi, Tiziano: No conflict of interest Lucchetti , Donatella: No conflict of interest Sgambato, Alessandro: No conflict of interest Cafarelli, Andrea: No conflict of interest Ricotti , Leonardo: No conflict of interest Vetrano, Stefania: No conflict of interest
Ricchi et al. (Thu,) studied this question.