A New Understanding of Brain Hemorrhages: Exploring the Role of Red Blood Cell Interactions

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By , Express Healthcare Management

A groundbreaking study conducted by the University of California, Irvine has unveiled a previously unknown contributor to the formation of brain hemorrhages that does not involve blood vessel injury. The research team discovered that interactions between aged red blood cells (RBCs) and brain capillaries can lead to cerebral microbleeds, shedding light on the underlying mechanisms and potential therapeutic targets for treatment and prevention.

Published in the Journal of Neuroinflammation, the study utilized advanced imaging techniques to observe the process by which RBCs become stalled in brain capillaries and subsequently trigger hemorrhages. Cerebral microbleeds are often associated with conditions that occur more frequently in older adults, such as hypertension, Alzheimer’s disease, and ischemic stroke.

Co-corresponding author Dr. Mark Fisher, a professor of neurology at UCI’s School of Medicine, emphasized the significance of this study in expanding our understanding of how cerebral microbleeds develop. He stated, “Our findings may have profound clinical implications, as we identified a link between red blood cell damage and cerebral hemorrhages that occurs at the capillary level.”

To investigate this link, the research team exposed RBCs to tert-butyl hydroperoxide, a chemical that induces oxidative stress. The treated RBCs, labeled with a fluorescent marker, were then injected into mice. Through two different imaging methods, the researchers observed the RBCs becoming lodged in brain capillaries and subsequently cleared out via endothelial erythrophagocytosis. As the RBCs were cleared, microglia inflammatory cells engulfed them, leading to the formation of brain hemorrhages.

Co-corresponding author Xiangmin Xu, a UCI professor of anatomy and neurobiology, highlighted the implications of their discoveries, stating, “We need to examine in detail the regulation of brain capillary clearance and analyze how this process relates to insufficient blood supply and ischemic stroke to advance the development of targeted treatments.”

This study marks a significant step forward in uncovering the contributors to brain hemorrhages and offers potential avenues for the development of new therapies. By focusing on the interactions between RBCs and brain capillaries, researchers can further explore the regulation of capillary clearance and its connections to other conditions such as ischemic stroke.

FAQ

What are cerebral microbleeds?
Cerebral microbleeds refer to small bleeding spots in the brain, often associated with conditions like hypertension, Alzheimer’s disease, and ischemic stroke. These microbleeds occur at a capillary level and were previously believed to be caused solely by blood vessel injury.

What did the study uncover?
The study discovered that interactions between aged red blood cells and brain capillaries can lead to cerebral microbleeds. By exposing red blood cells to oxidative stress and observing their behavior in mouse models, the researchers observed how the red blood cells become stuck in the capillaries and trigger the formation of brain hemorrhages.

What are the implications of these findings?
The findings of this study have significant clinical implications as they provide a new understanding of the development of cerebral microbleeds. Identifying the link between red blood cell damage and brain hemorrhages at the capillary level opens up potential avenues for targeted treatments and prevention strategies.

What further research is needed in this area?
Further research is needed to delve into the regulation of brain capillary clearance and to analyze its connection to insufficient blood supply and ischemic stroke. Understanding these processes can contribute to the development of more effective treatments for conditions associated with cerebral microbleeds.

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A new cause of brain hemorrhage has been identified

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Photo: Depositphotos

By Bronwyn Thompson, New Atlas

In a significant development for brain health, scientists have demonstrated for the first time how hemorrhages can occur due to a faulty interaction between aged red blood cells and narrow capillaries. Until now, the cause of this serious condition has been brain bleeding that results from injured or damaged blood vessels.

“It has always been assumed that in order for cerebral hemorrhage to occur, blood vessels need to be injured or disrupted,” said co-corresponding author Xiangmin Xu, professor at University of California Irvine (UCI). “We found that increased red blood cell interactions with the brain capillaries represent an alternative source of development.”

The team identified how aged red blood cells ‘stall’ in the brain’s narrow network of capillaries, which result in microbleeds at the site. Cerebral microbleeds in older adults have been linked to a higher risk of developing Alzheimer’s disease, hypertension and ischemic stroke.

While capillaries – the smallest blood vessels in the body – employ a clever membranous mechanism to push out any blockages, it’s a system that begins to falter with age.

The 2010 study that identified this mechanism also found that it becomes 30 to 50% slower in an aging brain, and also results in the death of more capillaries.

The team used tert-butyl hydroperoxide to cause oxidative stress to red blood cells, then marked the cells with a fluorescent tag and injected them into the brains of mice. Through two different methods, they saw the red blood cells becoming stuck in the capillaries, before being cleared through the process known as endothelial erythrophagocytosis. But as the cells moved out, microglia inflammatory cells engulfed them, forming a brain hemorrhage.

“We have previously explored this issue in cell culture systems, but our current study is significant in expanding our understanding of the mechanism by which cerebral microbleeds develop,” said co-corresponding author Mark Fisher, professor at UCI’s School of Medicine. “Our findings may have profound clinical implications, as we identified a link between red blood cell damage and cerebral hemorrhages that occurs at the capillary level.”

The team says this finding presents new avenues of research and potential treatment to help an aging brain maintain capillary function and to prevent those aged cells from stalling along this essential transport route.

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

The study was published in the Journal of Neuroinflammation.

Source: University of California Irvine

Click here to read full New Atlas article.