How Exercise Strengthens the Brain's Barrier Against Aging

A new study from the University of California, San Francisco (UCSF) has uncovered how physical exercise strengthens the blood-brain barrier (BBB) and boosts cognitive function. Published in Cell, the research highlights a liver-derived enzyme called GPLD1 that plays a key role in protecting the brain from age-related damage.

The findings suggest that even in later life, targeted molecular interventions could help reverse neurological decline by improving the barrier's selective permeability.

The UCSF team initially analysed over 1,200 proteins and molecules as potential regulators of the BBB. Their focus eventually narrowed to tissue-nonspecific alkaline phosphatase (TNAP), an enzyme linked to the barrier's deterioration with age. As people grow older, the BBB weakens, allowing harmful molecules to enter brain tissue and trigger chronic inflammation.

Exercise was found to elevate GPLD1 levels in the liver. This enzyme then cleaves TNAP from cell surfaces, effectively restoring the BBB's integrity and reducing brain inflammation. Tests in mice confirmed that lowering TNAP levels improved cognitive function in aged subjects, while high levels worsened decline.

The study emphasises that GPLD1, when activated by physical activity, indirectly reinforces the brain's vascular interface. Researchers believe that targeting TNAP cleavage mechanisms could lead to new therapies designed to rejuvenate the BBB in older adults.

The results reinforce the importance of exercise as a natural way to maintain neurovascular health. By modulating enzymes like GPLD1 and TNAP, future treatments may help counteract age-related cognitive impairment. The study opens potential pathways for developing drugs that mimic exercise's protective effects on the brain.