Superfund Research Program
November 2023
Researchers from the Louisiana State University SRP Center reported sophisticated methods to improve how environmentally persistent free radicals (EPFRs) are generated in the lab and used to study potential health consequences.
Particulate matter containing highly reactive EPFRs can be formed when organic waste or contaminated soils are burned as a remediation strategy, and the chemical components of EPFRs can vary based on their source. Inhaling these particles has been associated with inflammation and oxidative stress in the lungs; however, studying the potential health effects relevant to humans has been challenging in laboratory settings.
The team sought to develop and validate laboratory-based methods to generate EPFRs that are like those in urban environments, more closely mimic exposure conditions relevant to humans, and assess impacts on the heart and lungs as an understudied target of EPFR exposure.
The researchers used a novel two-stage combustion reactor to generate two groups of EPFRs with specifically controlled radical compositions at different concentrations. They verified that both groups of EPFRs had similar properties and estimated that the pollutants would deposit similarly within the lungs when inhaled. The chemical composition of the EPFRs were also similar to those found in particulate matter air pollution in the environment.
The team compared mice exposed to filtered air with those exposed to aerosolized EPFRs with either high or low concentrations of free radicals. Mice exposed to EPFRs with higher free radicals had reduced lung function and increased markers of vascular dysfunction. These mice also showed increased gene expression related to aryl hydrocarbon receptor activation – known to play an important role in detecting and responding to pollutants – and increased expression of genes involved in antioxidant response.
The approach will enable other researchers to produce consistent EPFR aerosols and explore more refined dose-response relationships, according to the authors. They added that their work could inform studies investigating how the source of EPFRs influence health outcomes.
To learn more, please refer to the following sources:- Aryal A, Noel A, Khachatryan L, Cormier SA, Chowdhury PH, Penn A, Dugas TR, Harmon AC. 2023. Environmentally persistent free radicals: Methods for combustion generation, whole-body inhalation and assessing cardiopulmonary consequences. Environ Pollut 334:122183. doi:10.1016/j.envpol.2023.122183 PMID:37442324