Microglia is a type of immune cell that is widely believed to make chronic adult brain diseases, such as Alzheimer’s disease and multiple sclerosis, worse. But research shows these cells can protect the brain from traumatic brain injury and may slow neurodegenerative diseases.
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A research team led by Bruce Trapp, PhD, Chair of the Department of Neurosciences at Cleveland Clinic’s Lerner Research Institute, found that microglia can help to synchronize brain firing. This synchronization protects the brain from traumatic brain injury and may help alleviate chronic neurological diseases.
The research gives the most detailed study and visual evidence to date of how the protection occurs. The research appears today in the online journal Nature Communications.
Protecting the brain
“Our findings suggest the innate immune system helps protect the brain after injury or during chronic disease,” Dr. Trapp says. “This role needs further study.”
Normally, microglia mediate immune responses in the central nervous system by clearing cellular debris and dead neurons from nerve tissue by consuming these cells. But researchers have long believed that after traumatic brain injury, that microglia cause harmful inflammation that destroys healthy brain cells.
However, others have theorized microglia may provide a more helpful role.
Dr. Trapp’s team used an advanced technique called 3D electron microscopy. They observed the microglia in action in animal models and what happens afterwards.
Helping brain cells survive
Microglia are the body’s first responders after a brain injury or during illness. The researchers found that when the body sends microglia into action, they travel to connections between brain cells that slow the firing of impulses. These connections are called inhibitory synapses. The microglia dislodge the synapse.
This leads to an increase in the firing of neurons, a specialized cell that transmits nerve impulses. This then kicks off a series of events that enhance the survival of brain cells.
“We could potentially harness the protective role of microglia to improve prognosis for patients with traumatic brain injury and delay the progression of Alzheimer’s disease, multiple sclerosis and stroke,” Dr. Trapp says. “The methods we developed will help us further understand mechanisms of neuroprotection.”
Traumatic brain injury happens when an external force has contact with the head and in some way injures the brain. Traumatic brain injury can vary from a minor blow that causes temporary dizziness or light-headedness to a life-changing brain injury due to major trauma. The most common cause is motor vehicle accidents, followed by sports injuries.
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