MicroRNAs Detected in Whole Blood Following Traumatic Brain Injury Are Associated with Recovery 6 Months after Injury

Traumatic brain injury (TBI) is a heterogeneous disease from which incomplete recovery is unfortunately common. Biomarkers prognostic of future recovery are currently lacking. MicroRNAs (miRNAs), small noncoding RNAs, are attractive potential biomarkers as they are stable in biofluids and can provide molecular mechanistic insights via the mRNAs they regulate. We measured miRNAs from whole blood in TBI participants (n = 106) within 24 h of injury and age- and sex-matched control participants (n = 107) using the NanoString Technology nCounter® miRNA expression panel. One hundred and nineteen miRNAs were differentially expressed in individuals who had sustained a TBI compared with control participants. Forty-seven of these had levels at 6 months postinjury that were similar to those within 24 h of injury, indicating that these acute differences persisted in the individuals with TBI. Furthermore, two of these 47 miRNAs were upregulated in participants who had incomplete recovery (functional outcome Glasgow Outcome Scale-Extended [GOS-E] score < 8) at 6 months after injury, compared with participants who had complete recoveries (GOS-E = 8). More work is needed to determine if miRNAs may serve as prognostic biomarkers of TBI outcome. MiRNAs may provide insights of the molecular networks and pathophysiological processes impacting recovery after injury warranting future study.