Neuronal and Glial Biomarkers in Urine of Athletes with Different Risks of Head Trauma to Monitor Sports-Related Concussions

Neuronal and glial biomarkers like glial fibrillary acidic protein (GFAP), ubiquitin C-terminal hydrolase-L1 (UCH-L1), tau protein, and neurofilament light chain (NfL) in serum are reported to be beneficial in detecting sports-related concussions (SRC) or intracranial trauma sequelae. However, routine blood measurements are invasive, and a non-invasive approach using urine could be advantageous. This prospective study analyzed urine samples from athletes with varying head trauma risks: high-risk (boxing), moderate-risk (American football, soccer), and low-risk (endurance sports). Samples were collected before (pre) and 48-72 h after (post) competition. Consecutive matches per athlete were sampled. Biomarker concentrations were adjusted for urine dilution using the creatinine ratio (CR). Statistical differences between groups were assessed using the Kruskal-Wallis test. A total of 48 athletes (boxing 11, American football 18, soccer 10, endurance 9) provided 112 samples. Ten SRC were recorded (boxing 9, soccer 1). Boxing athletes had the highest biomarker-CR, with significant differences in tau-CR and UCH-L1-CR compared to American football and endurance athletes (p = 0.005 and p = 0.001, respectively). No significant differences were found for NfL-CR or GFAP-CR. No significant changes were observed for biomarker-CRs 48-72 h after SRC. However, in a pooled analysis of all subsequent samples after a SRC, irrespective of the latency of sampling, there were significantly higher values for tau-CR and UCH-L1-CR (p = 0.02). Significantly higher levels of tau-CR and UCH-L1 were found in high-risk sports, potentially reflecting increased head impacts. However, an early increase of biomarker-CR within 72 h after SRC was not observed.