Circulating miR-125a but not miR-125b is decreased in active disease status and negatively correlates with disease severity as well as inflammatory cytokines in patients with Crohn's disease

AIM To determine the association of circulating miR-125a/b expression with the risk and disease severity of Crohn's disease (CD), and with inflammatory cytokines. METHODS Plasma samples were collected from patients with active CD (A-CD), or CD in remission (R-CD) and from healthy controls (HCs). The levels of the inflammatory cytokines interleukin-17 (IL-17), tumour necrosis factor-alpha (TNF-alpha), and interferon-gamma (IFN-gamma) were measured by enzyme-linked immunosorbent assay. The expression of miR-125a/b was assessed by quantitative polymerase chain reaction (qPCR). RESULTS Twenty-nine A-CD patients, 37 R-CD patients, and 37 HCs were included in the study. Plasma miR-125a expression was decreased in A-CD patients compared with that in R-CD patients (P < 0.001) and HCs (P < 0.001). miR-125a expression levels enabled the differentiation of A-CD from R-CD patients [area under curve (AUC) = 0.854] and from HCs (AUC = 0.780), whereas miR-125b expression did not. miR-125a was negatively correlated with C-reaction protein (CRP) (P = 0.017), erythrocyte sedimentation rate (ESR) (P = 0.026), Crohn's disease activity index (CDAI) (P = 0.003), IL-17 (P = 0.015), and TNF-alpha (P = 0.004) in A-CD patients. Furthermore, miR-125a was negatively associated with CRP (P = 0.038) and CDAI (P = 0.021) in R-CD patients. Regarding miR-125b, no association with CRP, CDAI, IL-17, TNF-alpha, or IFN-gamma was found in A-CD or in R-CD patients. miR-125a levels gradually increased in A-CD patients who achieved clinical remission (P = 0.009) after 3-mo treatment, whereas they remained unchanged among patients who failed to achieve remission. No changes in miR-125b expression were detected in remission or non-remission patients after treatment. CONCLUSION Circulating miR-125a but not miR-125b is decreased in patients with active disease status and negatively correlates with disease severity and inflammatory cytokines in patients with CD.