Background

Repeated head impacts in contact sports are linked to long-term brain disorders such as chronic traumatic encephalopathy (CTE), but the biological mechanisms driving this risk have remained unclear. Here, the researchers asked if ongoing damage to the blood-brain barrier (BBB), a protective layer that normally shields the brain from harmful substances, may persist in individuals many years after retirement. 

Research

Using advanced brain imaging, blood analysis, and postmortem tissue, the researchers show that retired athletes have persistent BBB disruption many years after leaving sport, which is strongly associated with cognitive decline in a subset of retired athletes. They also identify chronic immune activation, particularly involving the complement system, linking vascular damage to inflammation and neurodegeneration. 

Potential Impact

These findings suggest that BBB damage could serve as an early, detectable marker of brain disease risk in living individuals and provide new therapeutic targets focused on vascular repair and immune modulation. This opens the door to earlier diagnosis and intervention strategies for trauma-related neurodegeneration.