Effects of Eyjafjallajökull Volcanic Ash on Innate Immune System Responses and Bacterial Growth in Vitro

Martha M. Monick¹, Jonas Baltrusaitis², Linda S. Powers¹, Jennifer A. Borcherding¹, Juan C. Caraballo¹, Imali Mudunkotuwa², David W. Peate³, Katherine Walters⁴, Jay M. Thompson⁵, Vicki H. Grassian², Gunnar Gudmundsson⁶, and Alejandro P. Comellas¹

¹Department of Medicine, Carver College of Medicine, University of Iowa, Iowa City, Iowa, USA; ²Department of Chemistry, University of Iowa, Iowa City, Iowa, USA; ³Department of Geoscience, University of Iowa, Iowa City, Iowa, USA; ⁴ Central Microscopy Research Facility, University of Iowa, Iowa City, Iowa, USA; ⁵ARC Centre of Excellence in Ore Deposits, University of Tasmania, Hobart, Tasmania, Australia; ⁶University of Iceland, Reykjavik, Iceland

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Abstract

Background: On March 20, 2010, the Icelandic volcano, Eyjafjallajökull, erupted for the first time in 190 years. Despite many epidemiological reports showing volcanic ash effects on the respiratory system, there is limited data evaluating cellular mechanisms involved in the response to ash. Epidemiological work shows an increase in respiratory infections of subject and populations exposed to volcanic eruptions.

Methods: Volcanic ash was physicochemically characterized, demonstrating various sizes and presence of several transition metals, including iron. The effect of Eyjafjallajökull ash on primary alveolar and airway epithelial cells (20 to 100 μg/cm²), human alveolar macrophages (5 to 20 μg/cm²) and on Pseudomonas aeruginosa (PAO1) growth (2 μg/10⁴ bacteria) were tested.

Results: Volcanic ash had minimal effect on alveolar and airway epithelial cell integrity. In alveolar macrophages, volcanic ash disrupted pathogen killing and inflammatory responses. Volcanic ash, in in vitro bacterial growth models, increased bacterial replication and decreased bacterial killing by anti-microbial peptides.

Conclusions: These results provide potential biological plausibility for epidemiological data that associates exposure to air pollution with the development of respiratory infections. These data support the conclusion that volcanic ash exposure, while not seriously compromising lung cell function, may impair innate immunity responses in exposed individuals.

Citation: Monick MM, Baltrusaitis J, Powers LS, Borcherding JA, Caraballo JC, Mudunkotuwa I, Peate DW, Walters K, Thompson JM, Grassian VH, Gudmundsson G, Comellas AP. Environ Health Perspect (): .doi:10.1289/ehp.1206004

Received: September 11, 2012; Accepted: March 7, 2013; Published: March 11, 2013

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