Astrocytes Are Essential for Blood-Brain Barrier Health

A team of researchers at Virginia Tech has shared experimental evidence that astrocytes are essential for blood-brain barrier health. The research —published in today's edition of GLIA—reassesses traditional claims about the role of astrocytes in the brain and confirms the long-held assumption that astrocytes support the blood-brain barrier.

"Blood-brain barrier leakage is a problem in the aging brain as well as many different neurological diseases," said senior author Stefanie Robel. "Without astrocytes, the blood-brain barrier becomes leaky and ineffective, leaving brain tissue vulnerable to a variety of medical conditions. If we know what maintains the barrier in the healthy brain, we will be able to better understand what goes wrong in traumatic brain injury and in Alzheimer's disease—all health problems with blood-brain barrier damage."

In their study, the scientists genetically ablated a small number of astrocytes in adult mice to determine if the cells were necessary for blood-brain barrier health. They used small, intermediate-sized, and large molecular tracers to evaluate the permeability of the blood-brain barrier. All of the markers passed through the barrier in some areas, while in other areas only small tracers leaked, suggesting that leakages were happening at various sizes.

"When people sustain a concussion, we used to consider this a 'minor injury.' But our follow-up study shows that the blood-brain barrier leakage persists in areas where astrocytes are not functioning correctly, which suggests there is a long-term, lasting dysfunction in the barrier," said first author Benjamin Heithoff. "Understanding how that problem occurs and how it can be remedied are important public health questions. We have to know what makes this barrier functional in order to develop effective treatments when it becomes dysfunctional."