Scientists from the University of California, Irvine have made an important and surprising discovery about how brain hemorrhages may start.
For a long time, doctors believed that the main reason for bleeding in the brain was damage to blood vessels. This new research, however, shows that the problem may sometimes begin with aging red blood cells instead of injured blood vessels.
This finding challenges traditional ideas about brain bleeding and could change how doctors think about serious brain conditions in the future.
A brain hemorrhage happens when blood leaks into brain tissue, damaging nearby brain cells. It can cause symptoms such as headaches, confusion, trouble speaking, weakness on one side of the body, or even death.
Many people know that high blood pressure, head injuries, and blood vessel problems can cause this kind of bleeding. But the new study suggests that the blood itself, especially old and damaged red blood cells, may also be part of the problem.
The research team was led by Dr. Mark Fisher and Dr. Xiangmin Xu. They wanted to find out what happens when red blood cells become aged or damaged and travel through the very tiny blood vessels in the brain, known as capillaries.
Red blood cells normally carry oxygen throughout the body. As they age, they become weaker and more fragile. The scientists decided to focus on what happens when these aged cells move through the brain’s delicate capillaries.
To simulate aging in the lab, the researchers exposed healthy red blood cells to a chemical called tert-butyl hydroperoxide. This chemical created oxidative stress, which is a type of damage that can also happen in the human body over time.
After damaging the cells in this way, the scientists added a special fluorescent marker to them. This made the red blood cells glow under special microscopes so the researchers could track them inside the brain.
The glowing red blood cells were then injected into mice, and the scientists carefully observed what happened inside the brain.
What they saw was unexpected. Instead of passing smoothly through the tiny capillaries, some of the aged red blood cells became stuck. They stalled inside the narrow blood vessels, blocking normal blood flow. Shortly after that, the cells were removed by a type of immune cell in the brain called microglia.
Microglia normally help protect the brain by cleaning up waste and damaged cells. However, in this case, the process of removing the stuck red blood cells appeared to cause small amounts of bleeding, known as cerebral microbleeds.
These tiny bleeds are not always noticed at first, but they can accumulate over time and contribute to serious brain conditions.
This finding is important because cerebral microbleeds are often seen in people with high blood pressure, Alzheimer’s disease, and a history of stroke.
Until now, doctors mainly believed that these microbleeds came from weak or damaged blood vessels. This study suggests that damaged red blood cells themselves may play a direct role in causing these small brain hemorrhages.
Dr. Fisher explained that understanding this new mechanism could have major medical implications. If aging red blood cells can trigger microbleeds, then researchers and doctors may need to consider the health of blood cells, not just blood vessels, when studying and treating brain diseases.
This could lead to new approaches to prevent bleeding in the brain, especially in older adults or in people with conditions that damage red blood cells.
The team plans to continue studying how the brain clears away damaged cells in the bloodstream and how this process may be connected to other types of stroke.
By better understanding the way red blood cells interact with tiny brain vessels, scientists hope to develop new treatments that reduce the risk of brain hemorrhages and protect brain function.
These results may be especially important for an aging population. As people get older, their red blood cells and blood vessels both change. This could increase the chance of blockages, inflammation, and small bleeds in the brain.
Over time, these changes may affect memory, thinking, and movement. By discovering a new cause of microbleeds, researchers have opened the door to more targeted ways to protect brain health.
While more studies are needed, this research represents a major step forward. It reminds us that the human body is complex and that even tiny cells can play a big role in our health. A better understanding of these hidden processes may one day help millions of people avoid stroke, slow the progress of brain diseases, and live healthier, longer lives.
The full study was published in the Journal of Neuroinflammation, where scientists around the world can now examine and build on these important findings.
If you care about stroke, please read studies about how to eat to prevent stroke, and diets high in flavonoids could help reduce stroke risk.
For more health information, please see recent studies about how Mediterranean diet could protect your brain health, and wild blueberries can benefit your heart and brain.
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