Scientists have discovered that the glycocalyx, a protective sugar-rich layer on blood vessels, plays a crucial role in maintaining the blood-brain barrier (BBB)—the brain’s natural defense system. As we age or develop neurodegenerative diseases like Alzheimer’s, this protective layer weakens, making the brain more vulnerable to damage. But there’s hope! Researchers found that restoring certain sugar modifications using gene therapy strengthens the BBB, reduces brain inflammation, and even improves memory in aged mice.