Even small head impacts can damage neurons

A protein called PINCH, indicative of brain damage, was found in athletes.

A team of Temple scientists recently concluded a pilot study on mild repetitive concussions in soccer players, finding that those who had suffered repeated minor concussions had some indicators of mild brain damage.

The team tested blood samples from 10 soccer players with at least five years of professional or recreational playing experience for the biomarker PINCH, a protein normally found in damaged neurons.

“What PINCH will tell you is your blood brain barrier has opened, something leaked from the brain [to the blood] and the amount of the protein that has leaked is predictive of the amount of neuronal damage,” said Dr. Dianne Langford, the leader of the study and associate professor of neuroscience and neurovirology.

Langford’s previous work linked PINCH to hyperphosphorylated Tau, a protein associated with neuronal and synaptic damage.

When synapses are damaged, “things you used to know, you no longer do,” said Dr. Mary Barbe, who collaborates with Langford on a related project.

While other biomarkers for brain injury are currently being studied, PINCH is unique because it focuses specifically on brain damage, said Dr. Sara Ward, who also collaborates with Barbe and Langford on the project.

The blood samples were taken as part of another study in the Department of Kinesiology.

During the study, players were asked to head a series of soccer balls projected from a pitching machine in order to examine minor head impacts, said Dr. Ryan Tierney, who is involved with this other study.

“We project balls in a very controlled manner, very low speeds relative to game or ball practice speeds,” Tierney said.

“Then we’ll do blood tests … before and after the head impact to see if there’s any change in concentration of certain things,” he added.

Tierney shared blood samples from the study with Langford and her team last year. The team found no evidence of PINCH in the blood samples taken before the heading experiment. However, half of the samples taken after the heading experiment had PINCH.

These results indicate prior neuronal damage, and that the soccer players had PINCH in their brain from previous mild concussions. The heading experiment resulted in disruptions to their Blood-Brain Barrier, which allowed PINCH to leak from the brain into the bloodstream.

Langford explained that only half of the players had evidence of PINCH because susceptibility to brain damage depends on many factors, including genetics.

“If you take all of the football players that hit their heads, only some of them are going to develop CTE, Chronic Traumatic Encephalopathy,” she said.

Importantly, PINCH is usually undetected at the first instance of concussion.

“Over the season, over time, over years, over multiple concessions, you can detect PINCH in the blood and it is a direct correlate of hyperphosphorylated Tau in the brain,” Langford said.

The scientific team plans to reproduce these results on a larger scale and with other athletes, including football, soccer and water polo players. The next phase of the study will also include an animal model for mild repetitive concussions.

Langford hopes her findings will help athletes, coaches and physicians detect and better understand mild repetitive concussions. If PINCH is detected in an athlete’s blood, they may decide to stay on the sidelines until his or her brain recovers.

Many athletes could benefit from such tests: according to the National Institutes of Health, an estimated 300,000 sports-related concussions occur in the United States annually, and 90 percent of these concussions are considered mild.

Langford is quick to point out that her test is only one part of an array of ways to test for mild concussions in athletes.

“We already do [brain] imaging, we already draw blood, we do cognitive testing, we do behavior [evaluations] like balance and so forth,” she said. “What we’re missing is a blood marker to give us some information about what kind of proteins are in the brain [of people with mild repetitive concussion].”

Liora Engel-Smith can be reached at liora.engel-smith@temple.edu

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