H. pylori infection downregulates the expression and release of miR- 223 in neutrophils.

Objective: This study aimed to investigate the association between serum miR- 223 concentration and Helicobacter pylori (H. pylori) infection.

Methods: H. pylori status was assessed using the Urea ¹³C Breath Test Kit and Typing Detection Kit for antibodies against H. pylori. Patients were considered positive for H. pylori infection when both tests yielded positive results. Serum miRNAs were extracted using the miRNeasy Mini Kit, and quantitative real-time PCR was performed to analyze the relative expression level of miR- 223.

Results: We found that the relative expression level of miR- 223 in neutrophils from H. pylori-positive patients (20.35 ± 5.85) was significantly lower than that from healthy individuals (45.92 ± 10.59) (p < 0.05). Moreover, the expression level of miR- 7, which we selected as a control molecule, was not significantly lower in neutrophils from H. pylori-positive patients (3.07 ± 0.78) than healthy controls (4.43 ± 1.57) (p > 0.05), and the expression of miR- 7 was lower than miR- 223.

Conclusion: These results indicated that circulating miR- 223 down-expression was of neutrophil origin in vitro and inversely associated with H. pylori infection.