Serum MicroRNA signatures associated with hypertrophic callus formation in polytrauma patients with traumatic brain injury.

Long-bone fractures occasionally develop excessive callus formation in the presence of traumatic brain injury, a clinically relevant but poorly understood injury response. Although this phenomenon is known for decades, the causal factors are still underexplored, and no systemic biomarkers are currently available to predict the exuberant bone-mass-formation at an early timepoint after injury. In this study, we used small-RNA-seq, bioinformatic analyses, and in vitro assays to identify a set of micro-RNAs in sera of hypertrophic callus patients that could serve as potential biomarkers. The identified miRNAs are highly expressed in the human brain, particularly in the pituitary gland, and have been shown to regulate mRNA targets implicated in osteogenic processes.