Repairing leaky blood-brain barrier may rejuvenate brain function
New research in mice questions the idea that "you can't teach an old dog new tricks." The answer may lie in preserving the blood-brain barrier, which tends to become leaky with age.
The blood-brain barrier is a complex set of blood vessel characteristics that help shield the brain from potentially harmful substances in the bloodstream.
In a recent Science Translational Medicine study, scientists describe how the breakdown of the blood-brain barrier can trigger brain inflammation and cognitive impairment in aging mice.
The international team found that the breakdown of the blood-brain barrier activates a signaling protein in brain cells called astrocytes.
The researchers then developed and tested a drug that blocked the signaling protein, which goes by the name transforming growth factor-beta (TGF-beta).
After treatment with the drug, the mice showed fewer signs of brain inflammation and an improved ability to learn new tasks that matched the performance of much younger mice.
"We tend to think about the aged brain in the same way we think about neurodegeneration: Age involves loss of function and dead cells," says co-senior study author Daniela Kaufer, a professor of integrative biology at the University of California, Berkeley.
"But our new data tell a different story about why the aged brain is not functioning well: It is because of this 'fog' of inflammatory load," she adds.
Prof. Kaufer explains that within days of abolishing the "inflammatory fog," the aged brain starts to function more like a young brain.
The findings should help scientists better understand the decline of brain functions involving inflammation that can accompany aging and conditions such as dementia.
Investigating inflammatory fog
An increasing body of research — including imaging studies by co-senior study author Alon Friedman, of Ben-Gurion University of the Negev in Israel and Dalhousie University in Canada — shows that the blood-brain barrier becomes less efficient with age.
The leakier the blood-brain barrier becomes, the easier it is for substances that cause inflammation to cross over from the bloodstream into brain tissue and damage cells.
Kaufer and Friedman are also co-senior authors of another recent Science Translational Medicine study that took a closer look at inflammatory fog in leaky blood-brain barriers.
