The University of Toledo Translation Journal of Medical Sciences 
Cardiology Abstract, Department of Medicine Research Symposium UTJMS 2023 May 05; 11(1):e1-e2 

Harmful Algal Bloom Toxin Microcystin-LR Induces 
Macrophage Inflammation of Lung Tissues 

Shivani C. Patel1*, Joshua D. Breidenbach, MS1, Thomas M. Blomquist1, Andrew 
Kleinhenz1, Apurva Lad1, Robin C. Su, PhD1, Benjamin W. French1, Shereen G. 
Yassine1, James C. Willey, MD2, Jeffrey R. Hammersley, MD1, Amira Gohara, MD3, 
R. Mark Wooten, PhD4, Erin Crawford, Nikolai Modyanov5, MD, Deepak Malhotra,
MD6, Steven T. Haller, PhD1, David J. Kennedy, PhD1

1Division of Cardiology, Department of Medicine, The University of Toledo, Toledo, 
OH 43614 
2Division of Pulmonology and Critical Care, Department of Medicine, The 
University of Toledo, Toledo, OH 43614 
3Division of Pathology, Department of Medicine, The University of Toledo, Toledo, 
OH 43614 
4Department of Physiology and Pharmacology, The University of Toledo, Toledo 
OH 43614 
5Divison of Infectious Diseases, The University of Toledo, Toledo, OH 43614 
6Division of Nephrology, The University of Toledo, Toledo, OH 43614 

*Corresponding author: Shivani.Patel8@rockets.utoledo.edu

Published: 05 May 2023 

Introduction: Harmful Algal Blooms, or HABs, are rapidly growing algae or cyanobacteria that may 
produce toxins, which are dangerous for humans and animals. They arise from warm temperatures and 
nutrient pollution. HAB toxins, such as Microcystin-LR (MC-LR) present public health concerns, such 
as the transmission of HAB toxins via the generation of aerosols. Exposure to aerosolized HAB toxins 
may even potentially be linked to hazardous health consequences, such as airway inflammation. In 
previous studies, oral exposure to MC-LR in rodents led to macrophage infiltration of the colon. 
Therefore, the objective of this study was to investigate the role of macrophages in the airways in 
response to MC-LR exposure. 

Methods: C57BL/6J and BALB/c mice were exposed to MC-LR aerosols at a concentration designed to 
mimic potential environmental exposure. Lung tissues were analyzed for exposure dependent changes in 
gene expression, cytokine concentrations, and immune cell infiltration.   

Results:  Gene expression profiles of mice exposed to HAB toxin aerosols demonstrated a significant 
increase in the CD68 gene expressed by macrophages in C57BL/6J mice. Cytokine and chemokine 
protein concentration profiles also showed significant increases in multiple macrophage associated 

https://dx.doi.org/10.46570/utjms.vol11-2023-643 

https://dx.doi.org/10.46570/utjms.vol11-2023-643
mailto:Shivani.Patel8@rockets.utoledo.edu


https://dx.doi.org/10.46570/utjms.vol11-2023-643 UTJMS 11(1):e1-e2 

https://dx.doi.org/10.46570/utjms.vol11-2023-643 2 ©2023 UTJMS 

markers. Furthermore, IHC stains of lung tissue also revealed higher numbers of macrophages in 
C57BL/6J, but not BALB/c mice.   

Conclusion:  It appears that airways exposed to MC-LR aerosols respond with an increase in 
macrophage inflammation. These findings warrant further investigation into the impact of this toxin in 
populations with pre-existing airway inflammation. 

https://dx.doi.org/10.46570/utjms.vol11-2023-643
https://dx.doi.org/10.46570/utjms.vol11-2023-643