The link between football and long-term brain injuries is news that no one who's ever played the game wants to hear. Chronic traumatic encephalopathy, or CTE, can only be diagnosed after death, but scientists are looking for ways to change that.
It's ground-breaking research former NFL players are watching very closely.
Former Oklahoma Sooners and Chicago Bears tackle Caesar Rentie wonders if his health has yet to pay the price from his time on the gridiron.
"I'm always watching and looking for changes. Yearly I see a doctor and do all the things I do to take care of myself," said Rentie, now the vice president of pastoral services at Methodist Health System. "But it is something that I worry about."
Rentie played college ball in the 1980s and then went pro.
"You get a dinger and you feel dazed. You don't really think about it. You just shake it off and go to the next play," he said.
But now, a new study on former NFL players could help diagnose CTE while a person is still alive. It's about to start in three U.S. cities, including Phoenix, home to former Minnesota Vikings tight end Steve Jordan, who signed up for the trial.
"If we do nothing, then nothing gets done. That's kind of the basics of it," Jordan said.
Researchers will focus on the tau protein, which stabilizes nerve cells in the brain. In CTE, the tau protein forms clumps that slowly spread through the brain, killing brain cells. The tau protein plays a role in other neurodegenerative diseases, like Alzheimer's, but is the hallmark of CTE and has a distinct pattern inside the brain.
"Currently there are no treatments for CTE, but there are drugs and things that people are using for Alzheimer's disease that may diminish the amount of tau, and so maybe those things could be used in CTE," said co-lead researcher Kendall Van Keuren-Jensen, Ph.D.
Van Keuren-Jensen says that if she and her team can validate the tau protein as a biomarker, and if the protein can be isolated in a blood sample, it might be possible to develop a simple blood test for diagnosing CTE.
"I think we're going to help ourselves get closer to hopefully, a cure," Jordan said.
Dallas isn't a test site, so Rentie has to watch from the sidelines.
"It's important to be mindful of the studies and to do everything you can to take care of the players that play the game," he said.
But he will use the power of prayer to keep his mind at its best for as long as possible.
"Having a deep faith helps you cope with the struggles that you have," Rentie said.
Researchers hope to get 200 former NFL players to volunteer for the study. It would be the largest study yet of former NFL players, who are at high risk for CTE.
The study begins later this year.