Recent research has unveiled a potential link between head injuries and the reactivation of dormant viruses, which may contribute to the progression of neurological diseases. Conducted at Tufts University, the study utilized 'mini-brains' derived from stem cells to explore how brain tissue damage could trigger the resurgence of herpes simplex virus 1 (HSV-1), even after the immune system had previously suppressed it.
Although the 'mini-brains' were not perfect replicas of human brains, they exhibited reactions similar to those observed in human brains subjected to repeated mild impacts. A week post-injury, researchers noted the formation of protein aggregates and tangles in the brain tissue, characteristics associated with neurodegenerative diseases like Alzheimer’s. Additionally, signs of neuroinflammation and significant increases in immune cells linked to inflammation were observed.
Emerging studies indicate that traumatic brain injuries, such as chronic traumatic encephalopathy (CTE), may pose a major risk factor for developing neurodegenerative conditions. Chronic inflammation resulting from mild head trauma could contribute to cumulative damage over time.
In a related study from 2008, it was reported that genes from HSV-1 were present in 90% of protein plaques in the brains of deceased Alzheimer’s patients, with most viral DNA found within these plaques, raising questions about the role of viruses in disease progression.
To further investigate the influence of brain injuries on virus reactivation, researchers from Tufts University and the University of Oxford employed isolated brain slices. The findings revealed that individuals harboring dormant HSV-1 released lower amounts of the excitatory neurotransmitter glutamate—crucial for stimulating neuronal activity and involved in various cognitive processes—following physical injury.
The research team concluded that traumatic brain injuries could lead to the reactivation of HSV-1, with repeated injuries exacerbating the damage. They recommend further studies to explore potential mitigation strategies for the effects of head injuries, such as the use of anti-inflammatory and antiviral treatments post-injury, aimed at reducing HSV-1 reactivation in the brain and potentially curbing the progression of Alzheimer’s disease.
This study was published in the journal Science Signaling.