The new NIEHS Early Career Investigators Webinar series continued on May 11, with a presentation of Marissa Baker, Ph.D.on the mental health of seafarers during the COVID-19 pandemic, and a conference of Michael Petriello, Ph.D.on how chemicals such as per- and polyfluoroalkyl substances (PFAS) can affect the gut microbiome.
Baker, an assistant professor at the University of Washington, is affiliated with the school’s Interdisciplinary Center for Exposures, diseases, genomics and environment. Petriello, a pharmacology student at Wayne State University, is affiliated with the school Center for Urban Responses to Environmental Stressors. Both entities are supported by the NIEHS Environmental Health Sciences Core Centers Program.
The webinar series is hosted by Maria Jose Rosa, Dr PHand Douglas Walker, Ph.D.members of Mount Sinai Transdisciplinary Center on Early Environmental Exposures.
COVID-19 and seafarers’ mental health
Baker characterizes workplace exposures experienced by vulnerable or underrepresented populations. She explores the workplace determinants of understudied occupational health outcomes, such as mental health, stress and fatigue.
His talk was titled “Seafarers’ Mental Health and Wellbeing During COVID-19 and Beyond.” She noted that before the pandemic, data on seafarers’ mental health was limited.
“It really hadn’t been evaluated at all in this population,” Baker said. “We assumed it was good. There had been a study that looked at seafarers around the world, so it was really the pandemic that was the trigger that helped them realize that we need to do something about it.
She noted that more than 75% of U.S. trade involves shipping. In 2020, about 200,000 of the country’s seafarers were on 3,650 registered merchant marine vessels. Typically, sailors can encounter extreme weather conditions, long hours, lack of internet access and few people on board, which can lead to feelings of isolation.
These issues persisted when COVID-19 hit, and they were compounded by the lack of access to shore leave, Baker told attendees.
Sailors could no longer return home, voyages lengthened and work protocols changed. Baker conducted a survey to assess mental health outcomes and barriers to accessing care, seeking to prioritize interventions to improve seafarers’ well-being during and after the pandemic.
She rated the likelihood of five mental health problems based on 1,589 responses she received. Baker observed high rates of depression, anxiety, suicidal ideation, perceived stress, and PTSD. Women and young sailors had higher rates than their male and older counterparts.
Although sailors have had high job satisfaction, the rate of mental health adverse effects warrants intervention and continued evaluation, according to Baker. She recommends proper training and communication; increasing privacy for browsers to access telemental health; increasing social support on board; focus on the needs of underrepresented women and young seafarers; and corporate reporting policies.
Pollution and gut microbiome
Petriello studies how chemicals such as PFAS and polychlorinated biphenyls (PCBs) can alter the gut microbiome and potentially influence atherosclerosis. This condition is marked by a buildup of plaque on the walls of the arteries and contributes to cardiovascular disease.
Cardiovascular diseases are influenced by interactions between non-modifiable factors such as genes and family history, and modifiable factors such as environment, diet and lifestyle. To study the progression of atherosclerosis, Petriello examined lipid markers, cholesterol and inflammation in mice predisposed to hypercholesterolemia.
“We can expose mice to our pollutant of interest and check if atherosclerosis has accelerated,” he said.
In his work, mice exposed to PCBs developed lesions and markers of inflammation. They were also more likely to absorb compounds that resemble cholesterol, which could predispose them to atherosclerosis. Additionally, PCBs depleted the gut microbiota that metabolizes cholesterol.
“For toxicology, it’s interesting to think that the microbiota metabolizes pollutants, but also that pollutants can directly impact bacterial health,” Petriello said.
He exposed mice to a mixture of PFAS and found that the chemicals increased circulating cholesterol and inflammation in the livers of female mice. In another study, PFAS increased circulating cholesterol levels in some mice and decreased bile acid excretion, a mechanism that may raise cholesterol levels and deserves further study, according to Petriello.
(Susan Cozier is a contract writer for the NIEHS Office of Communications and Public Liaison.)