Wear a helmet!
by Ulrik Larsen
Repeated hits to the head (called repetitive head impacts, or RHIs) from contact sports like football are the biggest known risk factor for developing chronic traumatic encephalopathy (CTE, classified as tauopathy), a brain disease linked to sleeping problems, memory loss, mood problems, and other symptoms later in life. CTE can only be confirmed after death, and scientists still don’t fully understand what triggers the early buildup of abnormal tau proteins in the brain, a hallmark of the disease.
In this study, researchers looked at brain tissue from people under the age of 51 years who had been exposed to repetitive head impacts, most of whom were football players (other contact sports, such as soccer, were also included but with fewer donors). Using single-nucleus RNA sequencing to analyze how individual brain cells behave, they compared three groups: people with no head impact exposure, people exposed to repetitive head impacts but without CTE, and people with early-stage CTE.
They found that even before clear symptoms of CTE appear, the brains of those exposed to repetitive impacts already show major cellular changes. These include:
-Inflamed microglia that release a molecule called SPP1, which has a potential role in synaptic engulfment shown in Alzheimer´s models.
-Endothelial cells showing inflammation and signs of angiogenesis, with increased activity of support cells (astrocytes).
-Changes in synaptic related genes and loss of sulcal excitatory layer 2/3 neurons (specific type of neuron in the cerebral cortex region) happens before abnormal tau buildup.
-Finally, the researchers found clues that TGFβ1 might help microglia and blood vessel cells communicate in ways that could worsen brain inflammation.
Overall, this study shows that years of repetitive head impacts can cause lasting changes in many types of brain cells long before the classic CTE protein buildup starts. These findings could help scientists develop earlier tests and treatments for people at risk of CTE and potential parallels to other neurodegenerative diseases.
Continue your reading here:
Repeated head trauma causes neuron loss and inflammation in young athletes.
Butler MLMD, Pervaiz N, Breen K, Calderazzo S, Ypsilantis P, Wang Y, Breda JC, Mazzilli S, Nicks R, Spurlock E, Hefti MM, Fiock KL, Huber BR, Alvarez VE, Stein TD, Campbell JD, McKee AC, Cherry JD.
Nature. 2025 Nov;647(8088):228-237. doi: 10.1038/s41586-025-09534-6
Nature. 2025 https://doi.org/10.1038/s41586-025-09534-6