Temple kinesiology researchers are developing better ways to study the risks of mild head impact.
This past year, Temple University was included as one of 30 research institutions in a landmark study of traumatic brain injury funded by the U.S. Department of Defense and the NCAA. Here Associate Professor of Kinesiology Ryan Tierney, who is part of the new study, discusses another pioneering branch of traumatic brain injury research with his collaborators Associate Professor Joon Park and Assistant Professor Matt Hudson, also in the Department of Kinesiology. They discuss how they are combining their expertise to reshape our understanding of concussion.
Q: When assessing the effects of a head impact, it’s about more than just whether someone shows signs of concussion. How is your joint research changing the way we think about traumatic brain injury?
Tierney: We’re focusing on subconcussion, which is a head impact that doesn’t result in any outward signs or symptoms of concussion. Standard clinical tests remain normal, but the skull and brain are receiving this mechanical energy. More and more, we see problems developing for some retired athletes who have had thousands of subconcussions— very mild head impacts—over the course of their careers. Those impacts may accumulate over a lifetime and maybe causing degenerative changes in the brain. The question is how, and why? In our study, we’re taking a snapshot of mild, repetitive head impacts, using soccer heading. We’re controlling when the head impact occurs, the direction, and the magnitude, to study subconcussion in a standardized, well-defined way. Before and after, we draw blood and conduct other clinical measures. And then we look at whether these minor head impacts are changing anything.
Q: In your joint research, you are examining substances called biomarkers that are released by bodily tissues into the blood. Why are you focusing on biomarkers?
Tierney: Biomarkers are important for studying subconcussion because we can get a picture of what’s going on inside the brain by measuring things in the blood. When somebody has a concussion, sometimes they can mask it. It would be nice to have a definitive, easy-to-administer test that could indicate a concussion, rather than having to rely on this person self-reporting symptoms.
Park: Right now there’s no biological understanding of what’s accumulating in the brain with repetitive head impacts, and how. Is there a way to minimize or prevent those accumulations? We’re taking an innovative approach, merging our expertise to better understand the biological consequences of repetitive mild head impact.
Q: So how are your labs analyzing biomarkers, and what are you finding?
Park: My lab looks at tiny particles called microvesicles that are released from blood vessels in the blood-brain barrier or other tissues inside the brain. These particles carry bioactive molecules from the cell of origin, which can tell us if there are subtle changes in the brain tissues. By assessing the molecules in each microvesicle, we are trying to see whether repetitive mild head impacts would somehow cause brain damage in the participants in Dr. Tierney’s study. Our pilot studies have shown that there are significant changes in the number of specific microvesicles that may be associated with potential brain injury. Hudson: And my lab analyzes exosomes—particles which are even smaller than the microvesicles that Dr. Park’s lab looks at. Using advanced genetic sequencing techniques, we identify changes in the levels of thousands of different small ribonucleic acids (called microRNAs) which are found inside these exosomes and can indicate what’s happening inside bodily tissues. Our preliminary data shows that some microRNAs related to neural function and brain damage are changed after repeated mild head impacts. We also see changes in microRNAs that have never been studied before, but that may be involved in brain damage.
Q: What are the implications of finding a biomarker that lets us reliably identify mild head injury?
Park: There are no known biomarkers that provide direct information to the physician on what needs to be done for athletes who experience subconcussive head impact. So our research might help physicians decide how to manage their patients, even if a patient doesn’t have clinical symptoms of concussion. Because if those athletes return to the field without complete remediation of a brain injury, it can cause a secondary, more severe concussion.
Hudson: It’s definitely an unmet need. It would help coaches decide when athletes can return to the field. If an athlete had an elevated biomarker in their blood, the coach could decide to wait until the biomarker returned to a normal level.
Tierney: It’s also of interest societally—a parent wanting to know, “Should my son or daughter play football or soccer?” It’s hard because the fear involved is far ahead of the science. You see the newspaper articles about retired athletes having issues. But it’s apples and oranges compared to youth soccer. Head impacts take place all the time—and athletes go on to live happy and healthy lives. But we don’t know how many head impacts might cause problems, and why some people are fine and others aren’t. We’re trying to make the unknown more known.
Q: How is Temple different in approaching concussion research?
Tierney: Not every kinesiology department has different researchers to bring together to study concussion. Our department is composed of athletic training, exercise physiology, and specific lab work. And that means we have the ability to answer very interesting questions in an integrated way, as nobody else can.
Hudson: We’re taking a multifaceted approach. We’re all doing research that contributes in some way and combining our different areas of expertise. It’s the way collaboration should work. Another major part of it is the range of experiments and analyses that we have the capability to do at Temple. We don’t have the answers yet—but as this field continues to grow, I think we have the innovation, resources, and facilities to continue to stay on the cutting edge.