New UCSF study, published today in Nature Neuroscience, identifies a destructive cellular process that weakens artery walls and could help physicians identify high-risk aneurysms earlier

HANOVER, Mass., June 10, 2026 /PRNewswire/ — The Brain Aneurysm Foundation (BAF), the leading advocacy organization supporting education, research, and policy to transform the treatment of brain aneurysms, today highlighted a major new study from the University of California, San Francisco (UCSF). The research, supported in its early stages by BAF funding, helps explain how brain aneurysms form and weaken, and could point toward new ways of identifying which ones are most dangerous.

The findings, published today in Nature Neuroscience, reveal a destructive feedback loop between scar-forming cells and immune cells within human artery walls that gradually weakens the vessel. The work could lead to new ways of predicting which aneurysms are most likely to rupture and, eventually, to treatments that stabilize them before they burst.

Approximately 1 in 50 people have an unruptured brain aneurysm, yet predicting which ones will rupture remains a challenge. Treatment decisions today rely largely on an aneurysm’s size and location rather than its underlying biology. More than 30,000 ruptures occur in the United States each year; roughly half are fatal, and nearly two-thirds of survivors are left with lasting neurological deficits.

“Clinicians traditionally have relied on the size and location of an aneurysm to estimate its danger. By revealing the biology that drives an aneurysm to weaken, Dr. Winkler and his team have opened a path toward predicting risk far more accurately,” said Christine Buckley, executive director of BAF. “This is an important step forward for the field and for the millions of people living with an aneurysm, and it may transform our understanding of who is most at risk of rupture. This is exactly the kind of discovery we hope to make possible when we fund bold ideas.”

Analyzing more than 100,000 individual cells from human aneurysms and healthy brain arteries, the UCSF team identified 19 distinct cell types and mapped how they are organized within the vessel wall. In aneurysm tissue, supportive smooth muscle cells had disappeared and been replaced by stiff, scar-forming cells called fibroblasts. A type of immune cell called a macrophage accumulated nearby, and the two cell types reinforced one another in a damaging cycle: the fibroblasts released a signal that prompted the macrophages to produce enzymes that break down the vessel’s structural support, further weakening the wall. When researchers blocked that signal, the macrophages produced fewer destructive enzymes.

Today, aneurysms can be repaired through surgery or minimally invasive procedures, but because size is an unreliable predictor of risk, smaller aneurysms are typically monitored rather than treated. By pointing to the biological processes that weaken vessel walls, the new work could help physicians identify dangerous aneurysms earlier and intervene sooner — rather than waiting for size thresholds that may not capture the true risk.

“Foundational discoveries like this one don’t happen without early support,” said Ethan Winkler, MD, PhD, assistant professor of Neurological Surgery at UCSF and senior author of the study. “We are grateful to the BAF for their willingness to invest in understanding the basic biology of how aneurysms form as that early funding gave us the opportunity to advance this work. Continuing to fund early-stage research is how our field will keep moving toward better answers, and better outcomes, for patients.”

The BAF is the largest private funder of brain aneurysm research, and its strategic investments fuel breakthroughs in early detection, prevention, treatment, and technology. Early-stage BAF grants are designed to help researchers pursue potentially transformative research and generate the preliminary data needed to attract larger funding and advance toward clinical impact.

Despite the prevalence and severity of brain aneurysms, federal investment in related research remains far below funding levels for many other neurologic conditions, amounting to less than $3 per year for every person affected.

About the Brain Aneurysm Foundation

The Brain Aneurysm Foundation (BAF) is the leading advocacy organization supporting education, research, and policy to transform the treatment of brain aneurysms, and is the largest private funder of brain aneurysm research. Through its strategic grant program, BAF fuels breakthroughs in early detection, prevention, treatment, and technology, advancing the standard of care and improving outcomes for patients. To learn more, visit bafound.org.

Media Contact:
Lynn Nuttall
Director of Marketing and Communications
Brain Aneurysm Foundation
781-826-5556 x 208
lynn@bafound.org
bafound.org

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SOURCE Brain Aneurysm Foundation