Algae, Aerosols, and Asthma | Ohio Sea Grant

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Algae, Aerosols, and Asthma

12:00 pm, Tue March 26, 2024 – Ohio Sea Grant researchers recently made a breakthrough in understanding the risks of breathing in "aerosolized" algal toxins, finding evidence that airway exposure to the algal toxin microcystin can create an inflammatory response in lungs

When harmful algal blooms arise on Lake Erie each summer, people generally know that it’s not safe to ingest water affected by algae. What’s less known, however, are the health risks involved when people breathe in air containing algal toxins.

Researchers recently made a breakthrough in understanding these risks. Drs. Steven Haller and David Kennedy, associate professors at The University of Toledo College of Medicine and Life Sciences, found evidence that airway exposure to the algal toxin microcystin can create an inflammatory response in lungs that is exacerbated in experimental models of asthma.

person standing next to laboratory equipment

Bivek Timalsina, Ph.D. candidate at The University of Toledo College of Medicine and Life Sciences, stands next to specialized aerosol equipment used to study the health effects of breathing in algal toxins.

Now, the team is working with healthcare providers, public health officials, and Ohio residents to share their findings and answer questions.

“It’s gratifying to equip healthcare providers with this information so that they can use evidence-based medicine to help patients who may be at-risk for these types of exposures,” Kennedy said.

The research, funded through the Ohio Department of Higher Education’s Harmful Algal Bloom Research Initiative, looked at aerosols — small particles or droplets suspended in the air — that form through freshwater waves breaking. These “lake spray” aerosols can travel over 19 miles from their original source, and studies have shown that they can carry cyanotoxins from algal blooms. Natural wave motion and, notably, recreational activity can form these tiny bubbles.

“If you’re out on a boat or a jet ski and you’re just stirring up the water, that can also generate aerosols,” said Haller, who served as lead researcher for the project. “Up to this point, the main concern has just been the ingestion of contaminated water, so this is definitely an emerging area.”

When Haller and Kennedy learned about aerosols forming on the Great Lakes, pre-existing asthma came to mind. Asthma — a chronic condition that inflames and narrows airways in the lungs — affects 235 million people globally, and rates of asthma are particularly high in Toledo and other Great Lakes cities.

“That led us to ask, what happens? How are these aerosols affecting the lungs?” Haller said. “If you have asthma, are you even more prone to some of those effects?”

To investigate this, Haller and Kennedy conducted experiments on both experimental animal models and human cells to see how they respond to exposure to aerosolized microcystin-LR (MC-LR), one of the most abundant and potent algal toxins. Human airway tissue cells were sourced from both healthy and asthmatic volunteers who consented to biopsies.

Researchers used a special system to nebulize — turn into an aerosol — algal toxins and distribute them on the surface of the cells, which are grown to replicate the lining of cells in the lungs. This allowed for the exposure to be very controlled and defined, Kennedy said.

“Using donated human lung cells provides a tremendous advantage to our research,” Kennedy said. “They exhibit a lot of the same characteristics that you would see in real life. We try to get as close as possible to what would happen if you or I were out and exposed to these aerosols. How would they respond?”

two men wearing lab coats

Associate Professors David Kennedy, left, and Steven Haller work to share comprehensive insights into the prevention, diagnosis, and treatment of health issues associated with harmful algal bloom toxins

While the human cells were only exposed to microcystin for three minutes every three days, researchers were surprised to see an inflammatory response in healthy cells. They saw a similar inflammatory response in healthy mice exposed to aerosolized MC-LR as well.

“We started with a very brief exposure and were not really expecting to see anything until we got to longer exposures,” Kennedy said. “But even after that short exposure in healthy cells, we saw a really significant response. That was one of the most eye-opening findings.”

Haller and Kennedy found that the response to the toxin — what genes were produced and how cells behaved — was very much like an asthma response. What’s more, asthmatic cells exposed to the toxin saw an exacerbated inflammatory response. This suggests that patients with pre-existing asthma may be particularly vulnerable to adverse health effects from contaminated aerosols.

While results largely showed injury to the lungs, Haller noted that his team observed increases in inflammation in downstream organs such as the liver and kidneys as well.

“In terms of the quality of the data, we are very excited about it because this is something that had not been reported in the literature,” Kennedy said. “There were almost no studies that actually looked at how human cells respond to microcystin aerosols, in part because the equipment you need is very specialized. So we were very fortunate to procure equipment that allows us to model real-world aerosol exposure.”

Moving forward, Haller and Kennedy plan to share the results with other researchers so it can be confirmed and expanded. Broadly, their team is working to share comprehensive insights into the prevention, diagnosis, and treatment of health issues associated with harmful algal bloom toxins.

students work with laboratory equipment while a man in a lab coat looks on

Dr. Steven Haller, right, works with student researchers to study how human cells respond to the potent algal toxin microcystin.

“This is one of the first studies of its kind, so it’s important to foster collaboration and further investigation in this emerging field,” Haller said. “This information will be invaluable, especially considering the limited knowledge surrounding the health effects of aerosolized toxins. Providing this information will empower physicians to better treat their patients and address any potential health concerns.”

This effort has resulted in significant outreach work. The team shares findings with a variety of stakeholders: the Toledo-Lucas County Health Department, the Ohio Department of Health, healthcare providers, local advocacy groups, among others. As the research progresses, findings could inform public health guidelines as well, Kennedy said.

“Locally, every summer, algal blooms are on people’s minds, but healthcare providers often have no clue what they should be looking for,” Kennedy said. “By identifying the tools that we have, the health effects, the at-risk populations, you can start to give that information so that healthcare providers go, ‘This make sense. Here’s what we should look for.’”

Next, the team will continue research in this field by setting up an air sampling station on Lake Erie. With funding from the Ohio Department of Higher Education’s Harmful Algal Bloom Research Initiative and working alongside fellow UToledo researcher Dr. Dragan Isailovic, researchers will be able to collect air coming off the lake and look at the health effects of different airborne algal toxins.

“These studies are really impactful, and we really want to thank Sea Grant and the Ohio Department of Higher Education,” Haller said. “These have just been outstanding funding mechanisms for us to actually do this work. It can’t be understated that, because of this funding, there’s no question that Ohio has the absolute best, most state-of-the-art understanding of this and is driving the conversation.”

For more information about the research, contact Dr. Haller at and Dr. Kennedy at

Ohio Sea Grant is supported by The Ohio State University College of Food, Agricultural, and Environmental Sciences (CFAES) School of Environment and Natural Resources, Ohio State University Extension, and NOAA Sea Grant, a network of 34 Sea Grant programs nation-wide dedicated to the protection and sustainable use of marine and Great Lakes resources. Stone Laboratory is Ohio State’s island campus on Lake Erie and is the research, education, and outreach facility of Ohio Sea Grant and part of CFAES School of Environment and Natural Resources.

ARTICLE TITLE: Algae, Aerosols, and Asthma PUBLISHED: 12:00 pm, Tue March 26, 2024 | MODIFIED: 2:59 pm, Wed March 27, 2024
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