Understanding the Inflammatory Response to Stroke in the Human Brain through Mouse Models

Dr. Vivian Nguyen, an Assistant Professor in the Department of Neurology at the University of Arizona spoke about her research using multiplex immunoassays from MilliporeSigma. Her lab is focused on mixed dementia and has recently published the first comprehensive characterization of the inflammatory response to stroke in the human brain. Dr. Nguyen is continuing to map the pathological changes that occur throughout the brain in the weeks and months following stroke in models of Alzheimer’s disease.

Neuroinflammation and Alzheimer’s Disease

Mixed dementia, as explained by Dr. Nguyen, is a condition in which pathology characteristics of more than one type of dementia co-exist in an individual, for example, stroke infarcts alongside the neuropathology characteristic of Alzheimer’s disease (AD). Following post-stroke dementia work, Dr. Nguyen’s lab wanted to determine the impact of inflammation lasting for months following stroke, why there is also chronic blood-brain barrier dysfunction, and whether stroke causes long-term dysfunction of the glymphatic system, which is the brain’s version of the lymphatic system. The goal of her research is to determine the contributing factors of mixed dementia in the hope of developing treatments in the clinic. Her work demonstrates that there is a persistent inflammatory response in the human brain following stroke. With her research, she endeavors to bring more scientific attention to the fact that inflammation following stroke is very slow to fully resolve. Her data suggests that not only is this neurotoxic of itself, it also has important consequences for the blood-brain barrier and the glymphatic system and is a cause of post-stroke dementia in some patients and mixed dementia in other patients, such as those with a risk for developing Alzheimer’s disease.

The Importance of Technology

There are several methodologies being employed by the Nguyen lab which include: immunostaining, confocal microscopy, electron microscopy, histology, flow cytometry, multiplex immunoassays, and mouse behavioral testing. The microscope techniques are vital for determining the distribution and localization of different immune cells with markers of neurodegeneration. Flow cytometry, which is also a technology offered by MilliporeSigma, is vital for the identification of the immune cells that localize with areas of neurodegeneration. Multiplex immunoassays are used for the precise measurement of various cytokines and neurodegenerative proteins present in the brains of the dementia subjects. Mouse behavioral testing is used to monitor the dementia phenotype in the mice. MilliporeSigma’s cytokine and chemokine portfolio kits were used to determine the characteristics of the cytokine and chemokine responses to stroke in both mouse and human brain tissue. The MILLIPLEX^® MAP panels provided more comprehensive immunology panel options for both mouse and human tissue compared to their competitors. Dr. Nguyen would recommend these kits. Expanding on this, “The kits have always worked well and the inclusion of quality controls within each kit means that we can easily authenticate and validate that they’ve worked well. Also, not only are these kits compatible with brain tissue, but we have used them on lysates from other tissues such as spleen and heart, as well as plasma.” Dr. Nguyen also notes that the kits have protocols that “are clear and easy to follow, they provide prompt and knowledgeable tech support, and they work seamlessly with MILLIPLEX^® Analyst Software, which we use to analyze our data and is very user-friendly.”

MilliporeSigma’s MILLIPLEX^® MAP panels being used for cytokine & chemokine testing.

Future Perspectives

The lab plans to continue to map the pathological changes (i.e. neuroinflammation, neurodegeneration, blood-brain barrier dysfunction, and glymphatic dysfunction) that occur throughout the brain in the weeks and months following stroke in both wild type mice and transgenic mouse models of Alzheimer’s disease. To date, most stroke research in rodent models and human studies has focused on the acute response to stroke. Dr. Nguyen’s research highlights the fact that the inflammatory response to stroke does not resolve as effectively in the brain as inflammation does in other tissues. They also plan to test whether neurotrophic compounds can mitigate these changes. They also have future plans to look at components of the prolonged inflammatory response to stroke to determine whether post-stroke dementia, and mixed dementia, can be treated by selectively ablating individual immune mediators. Determining how variable the inflammatory response to stroke is in different people, and how it is impacted by age-related comorbidities is also another direction Dr. Nguyen’s field must go.

For more information on Dr Nguyen's research read the following article.