Research Links Leaky Brain Barrier to Athletes' Damage

Groundbreaking study finds breakdown in blood-brain barrier is key to long-term brain health issues in retired collision and combat sports athletes

Mar. 19, 2026 at 5:12am

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Researchers at Trinity College Dublin and the FutureNeuro Research Ireland Centre have discovered that a breakdown in the blood-brain barrier is the key link between repetitive head injuries and long-term brain health issues in retired athletes, including cognitive decline and neurological damage. The study found that even years after retirement, retired rugby players and boxers showed significant disruption in the blood-brain barrier compared to controls, allowing inflammatory proteins to seep into the brain and trigger a cascade of damage.

Why it matters

This research represents a major step forward in understanding the long-term impacts of repetitive head injuries in sports, and could lead to new interventions to identify at-risk athletes early and potentially slow or stop the progression of brain damage. The findings also raise important questions about safety protocols and duty of care, especially for amateur and youth athletes in collision and combat sports.

The details

The researchers used advanced MRI scans on retired rugby players and boxers, as well as post-mortem brain tissue from athletes diagnosed with Chronic Traumatic Encephalopathy (CTE). They discovered that a "leaky" blood-brain barrier allows inflammatory proteins to enter the brain, triggering the buildup of toxic p-Tau proteins associated with Alzheimer's and other dementias. Retired athletes with the most extensive blood-brain barrier disruption also scored significantly lower on cognitive tests.

  • The research was published on March 19, 2026 in the journal Science Translational Medicine.

The players

Prof. Matthew Campbell

Professor of Neurovascular Genetics and Head of Trinity's Genetics Department, who led the research with Prof. Colin Doherty.

Prof. Colin Doherty

Professor of Epileptology and Head of Trinity's School of Medicine, who co-led the research with Prof. Matthew Campbell.

Dr. Chris Greene

First author of the paper and FutureNeuro StAR Lecturer in RCSI University of Medicine and Health Sciences.

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What they’re saying

“Even years after retirement, retired athletes showed significant BBB disruption compared to age-matched controls. This suggests that the damage from head impacts is a chronic, ongoing process.”

— Prof. Matthew Campbell, Professor of Neurovascular Genetics and Head of Trinity's Genetics Department

“We found that retired athletes with the most extensive 'leakage' in their brain barrier also scored significantly lower on cognitive tests, specifically those measuring memory and executive function.”

— Prof. Matthew Campbell, Professor of Neurovascular Genetics and Head of Trinity's Genetics Department

“The study highlights that MRI scans focused on the BBB could serve as an early warning system, identifying athletes at the highest risk for future brain disease while they are still living and (potentially) playing.”

— Dr. Chris Greene, First author of the paper and FutureNeuro StAR Lecturer in RCSI University of Medicine and Health Sciences

“We are now at a critical juncture in how we, as a society, accept what is allowable in the context of sports related head trauma, especially for the amateurs and under-18s involved in collision and combat sports such as rugby where the duty of care falls on teachers and amateur coaches who are usually parents themselves.”

— Prof. Colin Doherty, Professor of Epileptology and Head of Trinity's School of Medicine

What’s next

The researchers now aim to expand the work to include a wider range of athletes, including those in women's sports and amateur sports, to explore if these findings apply across all levels of collision/combat sports.

The takeaway

This groundbreaking research highlights the urgent need to address the long-term brain health impacts of repetitive head injuries in sports, especially for amateur and youth athletes. The findings could lead to new early intervention strategies and safety protocols to protect athletes' futures.