A new study published in Nature Communications has shed light on how aging blood vessels in
the brain may influence neurodegenerative conditions. Using a mouse model, scientists mapped
vascular changes across various brain regions, revealing significant findings that could advance
our understanding of conditions like Alzheimer’s and Parkinson’s disease.
The research highlights how aging affects brain blood flow, with the deepest sections of the brain
showing the most pronounced changes. Key areas associated with Alzheimer’s disease, such as
the basal forebrain and entorhinal cortex, were notably impacted. These regions showed reduced
vascular density and fewer supporting cells called pericytes, which play a crucial role in
maintaining blood flow and the blood-brain barrier.
The study found that as blood vessels age, they become more tortuous, reducing their efficiency
and increasing resistance. This leads to inadequate oxygen and nutrient delivery to brain cells,
contributing to neuronal death—a common feature in neurodegenerative diseases. Researchers
observed that aging blood vessels become less able to constrict and relax, further impairing
blood flow.
Dr. José Morales, a vascular neurologist, speculated that decreased branching of blood vessels
might increase flow resistance, while inflammation and reduced ability to regulate blood vessel
function could also play roles. Mustali Dohadwala, a cardiologist, added that compromised
endothelial integrity might contribute to these issues.
Interestingly, the study also noted that the aging brain’s response to hypoxia—low oxygen
levels—is impaired. Younger brains typically form new blood vessels in response to hypoxia,
but this adaptive response declines with age, exacerbating the risk of brain cell death.
While these findings are based on mouse models and may not directly translate to humans, the
researchers believe that similar molecular mechanisms likely exist across species. Future studies
using advanced imaging techniques in humans could further validate these results and potentially
reveal new approaches to treating or preventing neurodegenerative diseases.
