Scientists Discover New Cause of Brain Hemorrhage

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Scientists Discover New Cause of Brain Hemorrhage

Scientists Discover New Cause of Brain Hemorrhage

In a major breakthrough in brain health, scientists have for the first time demonstrated how the erroneous interaction between aging red blood cells and narrowed capillaries can lead to hemorrhage.

Until now, the causes of such severe conditions were believed to be solely due to vascular injury or damage leading to brain hemorrhage.

Professor Xiangmin Xu, a co-corresponding author from the University of California, Irvine (UCI), stated, “People have always thought that blood vessels must be damaged or disrupted for a brain hemorrhage to occur. We found that increased interaction between red blood cells and brain capillaries represents another developmental source.”

Co-corresponding author, Dr. Mark Fisher, a neurology professor at the David Geffen School of Medicine at the University of California, Los Angeles (UCLA), said, “Our research provides a new perspective on understanding the formation of tiny brain hemorrhages and may pave the way for innovative approaches to treat them in the future. Steve Zylius / UCI

The research team identified how aging red blood cells “stagnate” in the narrow capillary network of the brain, leading to microbleeding in that area. Microbleeding in the brains of elderly individuals is associated with a higher risk of Alzheimer’s disease, hypertension, and ischemic stroke.

Capillaries are the smallest blood vessels in the human body, employing a clever membrane mechanism to clear blockages. However, with age, this mechanism begins to decline.

A 2010 study identified this mechanism, revealing that in the aging brain, the operational speed of this mechanism slows by 30% to 50%, leading to more capillary deaths.

The research team induced oxidative stress on red blood cells using tert-butyl hydroperoxide, then fluorescently labeled these cells and injected them into the brains of mice. Through two different methods, they observed red blood cells getting stuck in capillaries and being cleared through a process called endothelial red cell phagocytosis. However, when cells were expelled, glial cells engulfed them, resulting in brain hemorrhage.

Scientists Discover New Cause of Brain Hemorrhage

Co-corresponding author, Professor Mark Fisher from the David Geffen School of Medicine at the University of California, Los Angeles, said, “We had explored this issue in cell culture systems before, but our current study is significant for expanding our understanding of the mechanism behind the formation of brain microbleeds. Our findings may have far-reaching clinical implications, as we have identified the link between red cell damage and brain hemorrhage at the capillary level.”

The research team stated that this discovery opens up new avenues for research and potential therapeutic methods to help maintain capillary function in the aging brain and prevent these aging cells from stagnating along this crucial transportation route.

Fisher added, “We need to delve into the regulation of brain capillary clearance in detail and analyze how this process is related to insufficient blood supply and ischemic stroke, the most common form of stroke, to help advance the development of targeted treatments.”

This research was published in the Journal of Neuroinflammation.