DOP120 Low-intensity Pulsed Ultrasound Modulates Metabolite Release Reflecting the Inflammatory Status of Colonic Mucosa
Authors: Pineda Chavez S E , Hrvat F , Vignolle G A , Gillitschka Y , Ciglar L , Martano G , Timo S , Morosi L , Legrottaglie C , Mori G , Wozny M , Carriles A A , Rizzo G , Nöhammer C , Corridoni D , Cafarelli A , Armuzzi A , Ricotti L , Vetrano S 
Published: January 2025

Abstract

Background
Recently, we investigated Low-Intensity Pulsed Ultrasound (LIPUS) as a non-invasive and safe method to identify circulating biomarkers that reflect the colonic mucosal status in experimental colitis models. Here, we evaluate the capability of LIPUS to reveal a wide spectrum of tissue-derived proteins and metabolites as potential biomarkers of colitis.

Methods
Acute colitis was induced in 10 female C57B6N mice by ad-libitum administration of 2,5% dextran sodium sulfate (DSS) for 7 days. Colon-focused LIPUS stimulation (38 kHz, 150 mW/cm2, 20% duty cycle, 3 minutes) was applied at day 7 of colitic and healthy mice. Blood samples were collected 2 hours post-LIPUS exposure and plasma was analyzed by Olink® proteomics and LC-MS untargeted metabolomics. STRING database and Metabolite Enrichment Analysis Set (MSEA) were used for comprehensive pathway evaluation of proteins and metabolites.

Results
As expected, DSS-treated murine plasma displayed altered proteomic and metabolomic profiles compared to healthy controls at baseline, with a significant exacerbation of IL-6, IL-17A and TNF-family inflammatory mediators, tryptophan intermediates and microbial metabolites. LIPUS did not alter the cytokine profile observed before stimulation. However, microbiota-associated compounds involved in tryptophan, glutamate and riboflavin pathways, as well as phospatidylcholine (PE) family members, such as Lyso-PE, were significantly enhanced in the blood of colitic mice after LIPUS stimulation, conceiving the inflammatory status of the intestinal mucosa. Conversely, LIPUS stimulation in healthy mice upregulated circulating factors (Tnni3, Dlk1, lgmn and Kitlg) which are expressed by intestinal epithelial cells and that play a role in the epithelial-immune cell crosstalk. Nucleoside precursors of the pyrimidine metabolism and galacturonate involved in the vitamin C synthesis, which are potentially involved in intestinal mucosa homeostasis, were also significantly increased after LIPUS stimulation in healthy mice plasma.

Conclusion
LIPUS differentially enhances the release of specific metabolites based on the inflammatory status of the colonic mucosa. Thus, uninflamed LIPUS-stimulated intestinal mucosa releases proteins indicative of mucosal health, whilst injured intestinal mucosa readily discharges metabolites associated with the inflammatory process. This suggests the potential utility of LIPUS as a non-invasive diagnostic tool for gut inflammation assessment, improving diagnostic accuracy and efficiency in patients with colonic disorders. Further research is needed to validate these findings in humans for clinical parameter correlation.

References
ImmUniverse project: this project has received funding from the Innovative Medicines Initiative 2 Joint Undertaking (JU) under grant agreement No. 853995. The JU receives support from the European Union’s Horizon 2020 research and innovation programme and EFPIA. The content provided in this abstract reflects only the author's view and neither the IMI JU nor the European Commission are responsible for any use that may be made of the information it contains.