Serum exosomal microRNA-144-3p: a promising biomarker for monitoring Crohn's disease

Background Crohn's disease (CD) has a tendency for recurrence and requires adequate monitoring and personalized treatment. Since endoscopy is considerably invasive, serum biomarkers are required as alternatives for CD monitoring. Toward this, exosomal microRNAs (miRNAs) may serve as promising candidates. In this study, we aimed to assess the role of serum exosomal microRNA-144-3p (miR-144-3p) as a biomarker for CD monitoring. Methods We prospectively recruited 154 patients without a history of surgery (Cohort 1) and 75 patients who were to undergo intestinal resection (Cohort 2). Serum samples were collected from Cohort 1 before colonoscopy and from Cohort 2 before surgery and during post-operative colonoscopic examination. The serum levels of exosomal miR-144-3p were measured using quantitative reverse-transcription polymerase chain reaction (PCR). Correlations between relative exosomal miR-144-3p levels, disease activity, and disease behavior were analysed. The area under the receiver-operating characteristic curve (AUC) was used to assess the predictive value of exosomal miR-144-3p regarding mucosal activity and post-operative recurrence. Results A 3.33-fold increase in serum exosomal miR-144-3p levels was recorded in patients with CD compared with those in healthy controls (P < 0.001). The exosomal miR-144-3p levels were positively correlated with the simple endoscopic score of CD (rho = 0.547, P < 0.001) as well as the Rutgeerts score (rho = 0.478, P < 0.001). Elevated exosomal miR-144-3p levels were correlated with the penetrating disease with high specificity (100% [95% confidence interval, 95.1%-100%]). The accuracy of exosomal miR-144-3p for identifying post-operative recurrence was higher than that of C-reactive protein (CRP) (AUC, 0.775 vs 0.639; P < 0.001). Conclusions Serum exosomal miR-144-3p is a reliable biomarker of mucosal inflammation and penetrating CD. It may identify endoscopic CD recurrence after intestinal resection with higher accuracy than CRP testing.