New role for an old acquaintance: miR-1246 as a new inflammatory and prognostic marker in polytrauma patients.

BACKGROUND: Based on a literature analysis, we hypothesized that miR-1246 has a high potential as new biomarker after trauma. This miRNA is already established in oncology but has not yet been described in polytrauma. METHODS: Plasma samples from polytraumatized patients with an ISS ≥ 16 were collected in the emergency room (ER) and 48 hours after trauma. The patients were divided into two groups: a group affected by polytrauma with a leading traumatic brain injury (TBI) (abbreviated injury scale head, AIShead > 4) and a group with a polytrauma without TBI (AIShead = 0). The expression of miR-1246 was measured using qRT-PCR in plasma and plasma extracellular vesicles (EVs). Lastly, we isolated CD171 + EVs by using a magnetic bead-based method and measured miR-1246 expression. RESULTS: In plasma, there was a significant increase in miR-1246 in the ER in polytrauma patients, but not in TBI patients. The EV miRNA expression was also significantly increased in the ER samples of the polytrauma patients (*p ≤ 0.0001), while an increase in the expression in the TBI patients (*p ≤ 0.01) was only observed after 48 hours. The systemic expression of miR-1246 correlated with the Injury Severity Score (ISS), creatine kinase and creatinine kinase MB (CK-MB), myoglobin, Interleukin (IL)-6 and the length of hospital stay. In CD171+neuro-EVs, the miR-1246 expression was also significantly increased. CONCLUSION: MiR-1246 was shown to be a marker for the patients' injury severity, the early inflammatory phase and the patients' outcome.