Temporal Changes in Microrna Expression in Blood Leukocytes from Patients with the Acute Respiratory Distress Syndrome

BACKGROUND:MicroRNA (miRNA) control gene transcription by binding to and repressing the translation of messenger RNA (mRNA). Their role in the acute respiratory distress syndrome (ARDS) is undefined. METHODS:Blood leukocytes from 51 patients enrolled in a prior randomized trial of corticosteroids for ARDS were analyzed. After screening eight patients with microarrays for altered miRNA expression, 25 miRNAs were selected for further analysis using RT-PCR in all 51 patients. RESULTS:On day 0, the 51 patients had APACHE III score of 60.4 ± 17.7 and PaO2/FiO2 of 117 ± 49. 21 miRNA were expressed at increased levels in blood leukocytes at the onset of ARDS compared with healthy controls. These miRNA remained elevated at day 3 and increased further by day 7 (log2 fold change from 0.66 to 5.7 fold, P