In the never-ending quest to slow down the harmful effects of aging and keep the mind sharp, scientists may have found a breakthrough, and it involves a slimy barrier lining the brain’s blood vessels.
As it happens, slippery proteins in the brain’s blood vessels form a protective barrier that breaks down with age, and this barrier could hold the key to shielding the organ from deteriorating, according to a study in mice at Stanford University in California, published on February 26.
Indeed, the study has shown that this gooey barrier weakens over time, potentially allowing damaging molecules into brain tissue and triggering inflammatory responses, but gene therapy to restore the barrier has decreased brain inflammation, as well as improved memory and learning in aged mice.
As Carolyn Bertozzi, a Stanford professor and Nobel-prize-winning chemist, explained, these results show promise in understanding molecules called mucins that line the interior of blood vessels throughout the body, and give mucus its slippery texture. In her words:
“Mucins play a lot of interesting roles in the body. (…) But until recently, we didn’t have the tools to study them. They were invisible.”
Specifically, mucins are large glycoproteins that play a crucial role in protecting and lubricating epithelial surfaces characterized by their dense O-linked glycosylation, which helps retain water and form gel-like structures. They are produced by epithelial tissues in most animals.
Brain goo in treating age-related diseases
They are also the key elements of the blood-brain barrier (BBB) that restricts the movement of certain molecules from the blood into the brain, and the integrity of which declines with age, but scientists knew little about mucins’ contribution to changes in the barrier and the brain homeostasis.
That is, until Sophia Shi, a graduate student at Stanford, focused on a mucin-rich layer called the glycocalyx, which lines blood vessels. After Shi and her colleagues looked at the changes to the glycocalyx in the brain as mice age, they made an important discovery. Per Bertozzi:
“The mucins on the young blood vessels were thick and juicy and plump. (…) In the old mice, they were thin and lame and patchy.”
Furthermore, they found that old mice had fewer mucins in a particular class than young mice, as well as that a decrease in the activity of enzymes required for the production of these mucins caused the BBB to become leakier. On the other hand, boosting the activity of those enzymes in old mice reduced the leakage and improved the animals’ performance on learning and memory tests.
All things considered, the above results demonstrate that rebuilding the ‘brain goo’ or endothelial glycocalyx layer may be an effective therapeutic route in fighting BBB breakdown and decreasing vascular permeability that play a role in age-related CNS diseases and neurodegeneration.
Meanwhile, researchers at Northeastern University in London have discovered that psilocybin, the psychedelic found in drugs like magic mushrooms, may help restore normal brain function after mild recurrent head trauma that leads to an increased risk of dementia, Parkinson’s disease, and chronic traumatic encephalopathy.
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