Plasma Extracellular Vesicle LncRNA H19 as a Potential Diagnostic Biomarker for Inflammatory Bowel Diseases.

BACKGROUND: Inflammatory bowel disease (IBD) is a complex gastrointestinal disease with 2 main subtypes of Crohn's disease (CD) and ulcerative colitis (UC), whose diagnosis mainly depends on the medical history, clinical symptoms, endoscopic, histologic, radiological, and serological findings. Extracellular vesicles (EVs) are now considered an additional mechanism for intercellular communication, allowing cells to exchange biomolecules. Long noncoding RNAs (lncRNAs) that are enriched in EVs have been defined as an ideal diagnostic biomarker for diseases. In this study, we investigated the expression differences of 5 lncRNAs in tissue and plasma EVs of active IBD patients compared with patients in the remission phase and healthy controls to introduce an EV-lncRNA as a noninvasive IBD diagnostic biomarker.

METHODS: Twenty-two active IBD patients, 14 patients in the remission phase, 10 active rheumatoid arthritis (RA) patients, 14 irritable bowel syndrome (IBS) patients, and 22 healthy individuals were recruited in the discovery cohort. In addition, 16 patients with active IBD, 16 healthy controls, 10 inactive IBD patients, 12 active RA patients, and 14 IBS patients were also included in the validation cohort. The expression levels of 5 lncRNAs in tissue and EV-plasma were evaluated by quantitative real-time polymerase chain reaction (qRT-PCR) . Machine learning and receiver operating characteristic (ROC) curve analysis were performed to investigate the distinguishing ability of the candidate biomarkers.

RESULTS: While the expression levels of lncRNAs CDKN2B-AS1, GAS5, and TUG1 were significantly downregulated, lncRNAs H19 and CRNDE were overexpressed in active IBD lesions. Expression of H19 was detected in plasma EVs whose isolation had been confirmed via dynamic light scattering, microscopy images, and western blotting. The classification results demonstrated the excellent ability of H19 in distinguishing IBD/active from IBD/remission, healthy control, RA, and IBS (area under the ROC curve = 0.95, 0.97,1, and 0.97 respectively).

CONCLUSIONS: Our study suggests that circulating EV-lncRNA H19 exhibited promising potential for the diagnosis of active IBD.