Researchers at the University of California, San Francisco (UCSF) have made significant strides in understanding the link between exercise and cognitive health. Their study reveals a biological process that potentially explains how physical activity enhances thinking and memory, particularly as individuals age.
As people grow older, the blood-brain barrier, which protects the brain from harmful substances, tends to weaken, leading to increased permeability. This can result in inflammation, a factor associated with cognitive decline and conditions such as Alzheimer's disease. Previous research by the UCSF team indicated that exercise in mice boosts levels of an enzyme called GPLD1, which seemed to rejuvenate the brain but left the mechanism unclear since the enzyme does not directly enter the brain.
The recent findings clarify this process. The researchers discovered that GPLD1 influences a protein known as TNAP. As mice age, TNAP accumulates in the cells forming the blood-brain barrier, contributing to its decline. During exercise, GPLD1 is released into the bloodstream, where it travels to the brain's blood vessels and removes TNAP, restoring the barrier's integrity.
Further experiments highlighted TNAP's critical role in cognitive function. Young mice engineered to produce excess TNAP experienced memory issues akin to older mice. Conversely, reducing TNAP levels in older mice improved the blood-brain barrier's permeability and enhanced memory performance.
The implications of this research could be substantial, suggesting that therapies aimed at reducing TNAP could help mitigate age-related cognitive decline and potentially offer new avenues for treating Alzheimer's disease. The study was published in the journal Cell and involved contributions from multiple UCSF researchers, supported by various funding sources, including the National Institutes of Health.