Salivary microRNA (miRNA) molecules continue to show promise as biomarkers to accurately diagnose sports-related concussion (SRC), as recently published research shows many are unaffected by the effects of exercise.

In a paper published in the Journal of Sport and Health Science, researchers found that two microRNAs, identified as markers of concussion in previously published research, were not influenced by active participation in contact sports or season-long training. Removing the confounding effects of exercise permits application of this biomarker to concussed athletes and, according to the authors, improves its potential utility as a sideline test for sports-related concussion.

In the present study, “Refinement of Saliva MicroRNA Biomarkers for Sports-Related Concussion,” the authors sought to refine the use of these biomarkers as a sideline assessment tool for sports-related concussion by excluding those microRNAs that are confounded by the effects of exercise. The multi-center, prospective study, involving 10 research institutions, collected 455 saliva samples from 314 individuals aged 8 to 58. The authors found that, while several salivary miRNAs were affected by exercise, two unaffected miRNAs could accurately differentiate individuals with concussion regardless of recent exercise.

The study also found two of the diagnostic miRNAs displayed relationships with subconcussive head impacts. The authors suggest this finding may eventually be used to assess athletes in contact sports for biologic effects of cumulative head impacts that raise concussion risk.

“This study advances the science behind salivary miRNA concussion biomarkers by identifying the miRNAs least impacted by exercise, and demonstrating that just two of them may accurately identify individuals with sports-related concussion,” says Steven Hicks, MD, PhD, associate professor of Pediatrics at Penn State College of Medicine, and lead author of the paper. “A panel of concussion miRNAs, down to just two molecules, is a crucial step toward applying these molecules in point-of-care devices. Importantly, the study also identifies miRNAs that increase with cumulative head impacts, and may telegraph an athlete’s risk for future concussion.”

Benjamin Perry, president of Quadrant Biosciences, a molecular diagnostics company that provided funding for the study, likewise noted the importance of these recent findings.

“Since the vast majority of concussions we encounter are sports-related, being able to account for biomarkers that fluctuate with exercise is instrumental in developing a pragmatic commercial diagnostic,” he says.