Scientists have shown that APOE4, the strongest genetic risk factor for late-onset Alzheimer’s, does not just tag along as brain blood vessels fail — it actively causes that failure by turning vessel-supporting cells into scar-producing cells and jamming the brain’s waste-disposal machinery.
The research
Two companion studies from the Bl Blanchard Laboratory at the Icahn School of Medicine at Mount Sinai were published in Cell and Cell Stem Cell. Corresponding author Joel W. Blanchard, PhD, Associate Professor of Neuroscience and Stem Cell Biology, led the team.
In the Cell paper, researchers built a single-cell transcriptomic atlas of the human brain’s vasculature, mapping gene expression across the cells that build and protect the blood-brain barrier. They found that APOE4 pushes pericytes — mural cells that wrap capillaries and keep vessels stable — into a transdifferentiation into scar-forming, myofibroblast-like cells. This drove vascular fibrosis and accelerated amyloid-beta deposition around vessels. Critically, inhibiting the TGF-β signaling pathway reversed this transition in aged APOE4 animal models, restoring pericyte coverage, suppressing scarring, and reducing vascular amyloid.
In the Cell Stem Cell study, the lab used their 3D human stem cell-derived brain model, called “miBrains,” grown from induced pluripotent stem cells (iPSCs) and integrating neurons, glia, and functional vasculature. They found APOE4 causes abnormal cholesterol accumulation in astrocytes, paralyzing lysosomal waste-disposal systems and allowing toxic alpha-synuclein to aggregate and spread to neurons. Targeting cholesterol metabolism cleared these aggregates.
First author Braxton R. Schuldt, an MD/PhD candidate, noted that blocking the protein buildup revealed possible therapeutic strategies for protecting brain circulation in people at high genetic risk.
Why it matters
Alzheimer’s disease affects more than seven million older adults in the United States. These findings reframe cerebrovascular decline as an active, potentially reversible process, not passive end-stage damage. For anyone curious about cognition, this means vascular health and cellular waste clearance are not background details — they are central to how the brain maintains memory and executive function. Understanding your genetic risk (APOE4 status) and monitoring cardiovascular health may become part of a proactive brain-care strategy.
What you can do
- Ask your doctor about cardiovascular risk factors — blood pressure, cholesterol, and glucose — since vessel health matters for brain waste clearance.
- Stay physically active; exercise supports vascular function and may help maintain pericyte coverage.
- Follow evidence-based sleep habits, as sleep is when the brain’s glymphatic system clears waste.
- Keep learning new skills to build cognitive reserve while research advances.
Source: Neuroscience News
Curious about your own brain? Take our free adaptive IQ test or try 306 brain training levels.