Kristian Doyle

Kristian Doyle

Associate Professor, BIO5 Institute
Associate Professor, Immunobiology
Associate Professor, Neurology
Associate Professor, Neuroscience - GIDP
Associate Professor, Neurosurgery
Associate Professor, Psychology
Member of the Graduate Faculty
Research Scientist
Primary Department
Department Affiliations
(520) 626-7013

Work Summary

Work Summary
Approximately 795,000 Americans suffer a stroke each year, and 400,000 will experience long-term disability. The number of stroke survivors in the population is expected to double by 2025. Currently, treatments for stroke patients are limited to tissue plasminogen activator (TPA), but its use is limited to the first few hours after stroke. Therefore, the goal of our research is to develop new therapeutics that can promote repair and recovery in this rapidly growing population.

Research Interest

Research Interest
The Doyle lab investigates the role of the immune system in causing dementia after stroke. Up to 30% of stroke patients develop dementia in the months and years after their stroke and we are testing the hypothesis that in some patients this is due to a chronic inflammatory response that persists at the site of the stroke infarct. We suspect that in the weeks, months and possibly years after stroke, neurotoxic inflammatory mediators, including T cells, cytokines and antibodies, leak out of the stroke infarct and cause bystander damage to the surrounding tissue, which then both impairs recovery, and in some instances leads to cognitive decline. In support of this hypothesis we have data that demonstrates that inflammation persists for months at the site of the infarct after stroke, and that a single stroke can directly lead to the development of immune-mediated delayed cognitive deficits. We are currently in the process of targeting different components of the prolonged inflammatory response to stroke to determine if post stroke dementia can be treated by selectively ablating individual immune mediators such as B lymphocytes, T lymphocytes, and CCR2. Keywords: Neuroinflammation, stroke, dementia, Alzheimer's disease


Bartlett, M. J., Flores, A. J., Dollish, H. K., Farrell, D. C., Parent, K. L., Besselsen, D. G., Heien, M. L., Doyle, K., Cowen, S. L., Steece-Collier, K., Sherman, S. J., & Falk, T. (2017). Neuroplastic mechanism of sub-anesthetic ketamine treatment to reduce development of L-DOPA-induced dyskinesia. Science Translational Medicine.
BIO5 Collaborators
David G Besselsen, Kristian Doyle
Doyle, K. P., Simon, R. P., Snyder, A., & Stenzel-Poore, M. P. (2003). Working with GFP in the brain. BioTechniques, 34(3), 492-4.
Doyle, K. P., Quach, L. N., Solé, M., Axtell, R. C., Nguyen, T. V., Soler-Llavina, G. J., Jurado, S., Han, J., Steinman, L., Longo, F. M., Schneider, J. A., Malenka, R. C., & Buckwalter, M. S. (2015). B-lymphocyte-mediated delayed cognitive impairment following stroke. The Journal of neuroscience : the official journal of the Society for Neuroscience, 35(5), 2133-45.

Each year, 10 million people worldwide survive the neurologic injury associated with a stroke. Importantly, stroke survivors have more than twice the risk of subsequently developing dementia compared with people who have never had a stroke. The link between stroke and the later development of dementia is not understood. There are reports of oligoclonal bands in the CSF of stroke patients, suggesting that in some people a B-lymphocyte response to stroke may occur in the CNS. Therefore, we tested the hypothesis that a B-lymphocyte response to stroke could contribute to the onset of dementia. We discovered that, in mouse models, activated B-lymphocytes infiltrate infarcted tissue in the weeks after stroke. B-lymphocytes undergo isotype switching, and IgM, IgG, and IgA antibodies are found in the neuropil adjacent to the lesion. Concurrently, mice develop delayed deficits in LTP and cognition. Genetic deficiency, and the pharmacologic ablation of B-lymphocytes using an anti-CD20 antibody, prevents the appearance of delayed cognitive deficits. Furthermore, immunostaining of human postmortem tissue revealed that a B-lymphocyte response to stroke also occurs in the brain of some people with stroke and dementia. These data suggest that some stroke patients may develop a B-lymphocyte response to stroke that contributes to dementia, and is potentially treatable with FDA-approved drugs that target B cells.

Felix, K. M., Jaimex, I. A., Nguyen, T. V., Ma, H., Raslan, W. A., Klinger, C. N., Doyle, K. P., & Wu, H. J. (2018). Gut Microbiota Protects Immunocompromised Hosts Against Pneumococcal Pneumonia. Frontiers in Cellular and Infection Microbiology.
Nguyen, T. V., Frye, J., Stepanovic, K., Hayes, M., Urzua, A., Serrano, G., Beach, T., & Doyle, K. (2016). Multiplex immunoassay characterization and species comparison of inflammation in acute and non-acute ischemic infarcts in human and mouse brain tissue.. Acta Neuropathologica Communications, 4(100). doi:10.1186/s40478-016-0371-y

This study provides a parallel characterization of the cytokine and chemokine response to stroke in the human and mouse brain at different stages of infarct resolution. The study goal was to address the hypothesis that chronic inflammation may contribute to stroke-related dementia. We used C57BL/6 and BALB/c mice to control for strain related differences in the mouse immune response. Our data indicate that in both mouse strains, and humans, there is increased granulocyte macrophage colony-stimulating factor (GM-CSF), interleukin-6 (IL-6), interleukin-12 p70 (IL-12p70), interferon gamma-induced protein-10 (IP-10), keratinocyte chemoattractant/interleukin-8 (KC/IL-8), monocyte chemoattractant protein-1 (MCP-1), macrophage inflammatory protein-1α (MIP-1α), macrophage inflammatory protein-1β (MIP-1β), regulated on activation, normal T cell expressed and secreted (RANTES), and Tumor necrosis factor-α (TNF-α) in the infarct core during the acute time period. Nevertheless, correlation and two-way ANOVA analyses reveal that despite this substantial overlap between species, there are still significant differences, particularly in the regulation of granulocyte colony-stimulating factor (G-CSF), which is increased in mice but not in humans. In the weeks after stroke, during the stage of liquefactive necrosis, there is significant resolution of the inflammatory response to stroke within the infarct. However, CD68+ macrophages remain present, and levels of IL-6 and MCP-1 remain chronically elevated in infarcts from both mice and humans. Furthermore, there is a chronic T cell response within the infarct in both species. This response is differentially polarized towards a T helper 1 (Th1) response in C57BL/6 mice, and a T helper 2 (Th2) response in BALB/c mice, suggesting that the chronic inflammatory response to stroke may follow a different trajectory in different patients. To control for the fact that the average age of the patients used in this study was 80 years, they were of both sexes, and many had suffered from multiple strokes, we also present findings that reveal how the chronic inflammatory response to stroke is impacted by age, sex, and multiple strokes in mice. Our data indicate that the chronic cytokine and chemokine response to stroke is not substantially altered in 18-month old compared to 3-month old C57BL/6 mice, although T cell infiltration is attenuated. We found a significant correlation in the chronic cytokine response to stroke in males and females. However, the chronic cytokine response to stroke was mildly exacerbated by a recurrent stroke in both C57BL/6 and BALB/c mice.