Strokes are caused by limited blood flow to the brain. Described as a cardiovascular disease, strokes result from a clogged or blocked blood vessel that leads to a lack of oxygen. Around 800,000 individuals have a stroke each year in the United States. The most common type of stroke is referred to as ischemic, which occurs when blood is occluded from a clot or narrow blood vessel. If the brain has low blood exposure, it limits the oxygen and nutrients the brain needs. As a result, brain cells begin to die, and a stroke occurs.
Many different things that block or destroy blood vessels can cause a stroke, but high blood pressure is the leading risk factor. Symptoms of a stroke include body fatigue, difficulty with speech, numbness in the face or limbs, loss of vision, headache, dizziness, and others. While it is understood how a stroke occurs, the long-term effects are still unclear. Scientists are currently working to understand more about this disease and how physicians can better treat patients after experiencing a stroke.
A recent article in Cell, by Dr. Arthur Liesz and others, demonstrate stroke effects on systemic immunity. Liesz is an Associate Professor in the Munich Center for Neurosciences at the Ludwig-Maximilians-Universitat Munichen (LMU) in Germany. His work focuses on the relationship between the brain and immune system. Specifically, his research investigates the impact of neuronal disease or damage on the immune system. In addition, Liesz has a strong interest in translational science to develop novel techniques for patient assessment and diagnosis.
Liesz and his team used animal models as well as human samples to learn more about systemic immunomodulation after a stroke. Through next generation sequencing, researchers found a distinct gene signature in specific immune cells. This gene signature indicated permanent changes related to inflammation. In addition, this signature was upregulated in specific immune cells, including macrophages, which are responsible for identifying and eliminating foreign pathogens. These patterns were found in several organs that disrupt intracellular mechanisms. Interestingly, these cellular changes are made by regulating which gene sequences in the DNA get translated and made into proteins, necessary for cell survival. Most of these changes within immune cells were detected in the heart and contribute to scarring and inefficient blood circulation.
Further investigation by the researchers indicated that a specific protein, known as IL1-beta, drives these genetic changes affecting immune memory. The authors clearly demonstrated that, with IL1-beta, stroke leads to innate immune memory which can cause cardiac dysfunction and more brain cell death. Additionally, when IL1-beta or specific immune were blocked cardiac dysfunction was prevented.
Liesz and others discovered that there are long-term effects in the immune system for those that experience a stroke. Importantly, the group demonstrated the mechanism that increases the risk of stroke. These results have a major impact on patients in the clinic. The work reported in this article provides critical information about stroke, which in turn can improve current therapeutic treatments for patients and even help prevent stroke occurrence in high-risk populations.
Article, Cell, Arthur Liesz, LMU
