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-α (TNF-α), and interferon-γ (IFN-γ) 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-α ( 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-α, or IFN-γ 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.