Papers of the Month
By Megan Avakian
E-cigarette aerosols damage cells important for lung health
Exposure to aerosols from electronic nicotine delivery systems (ENDS), or e-cigarettes, has toxic effects on cells important in lung function, according to an NIEHS-funded study.
The researchers exposed human and mouse lung epithelial cells to ENDS aerosol with and without nicotine. Both aerosols resulted in death of both types of exposed cells. Nicotine exposure alone did not cause cell death, but the presence of nicotine in the aerosol significantly increased cell death in human and mouse cells.
To examine effects on mouse immune cells, the researchers exposed a type of cell called a macrophage to ENDS aerosol. Macrophages clear pathogens and dead cells from the body and are important for maintaining healthy lungs. Compared with controls, ENDS-exposed macrophages had increased levels of inflammatory cell death. Rates of death were similar from aerosols with and without nicotine. When exposed to a lower, nonlethal dose of ENDS aerosol, macrophages showed reduced ability to clear away pathogens or dead cells. These reductions were more pronounced when nicotine was present in the ENDS aerosol.
Taken together, these results suggest that ENDS aerosol has toxic effects on cells important in lung function, and that this toxicity is enhanced by the presence of nicotine. These findings highlight the potential danger of ENDS use and should be considered by relevant regulatory bodies, the researchers said.
Citation: Serpa GL, Renton ND, Lee N, Crane MJ, Jamieson AM. 2020. Electronic nicotine delivery system aerosol-induced cell death and dysfunction in macrophages and lung epithelial cells. Am J Respir Cell Mol Biol 63(3):306–316.
Vitamin E needed to develop healthy nervous system
Embryos produced by vitamin E-deficient zebrafish had severely malformed brains and nervous systems, according to a study by NIEHS grant recipients. The researchers previously discovered that zebrafish embryos lacking the gene TTPA, which codes for a protein that controls vitamin E distribution in the body, have nervous system defects and die within 24 hours of fertilization. Here, they tested whether vitamin E, not just TTPA, was necessary for nervous system development.
The researchers fed zebrafish either vitamin E sufficient (E-pos) or deficient (E-neg) diets and spawned them to obtain embryos. They assessed embryo mortality as well as expression of TTPA and other genes that mark important neurodevelopmental timepoints. Using imaging techniques, they compared development of the brain, eye, and other nervous system structures in the embryos.
Vitamin E-neg embryos had higher rates of mortality and severe brain and eye deformation compared to vitamin E-pos embryos. Expression of genes critical in nervous system development and differentiation was altered in vitamin E-neg embryos. Imaging revealed defects in formation of the fore-, mid- and hindbrain of vitamin E-neg embryos. TTPA expression was not disrupted by the vitamin E status, suggesting that vitamin E itself, and not TTPA, is required for healthy brain and nervous system development.
Citation: Head B, La Du J, Tanguay RL, Kioussi C, Traber MG. 2020. Vitamin E is necessary for zebrafish nervous system development. Sci Rep 10(1):15028.
PFAS exposure while pregnant linked to later cardiometabolic risk
NIEHS-funded researchers found that mothers exposed to per- and polyfluoroalkyl substances (PFAS) during pregnancy have a higher risk for poor cardiometabolic health in the years following birth. According to the authors, this study is the first to assess associations between PFAS exposure in pregnancy and maternal cardiometabolic health after birth. PFAS, a large group of synthetic chemicals found in a variety of consumer products, have been linked to immune dysfunction, altered metabolism, and certain cancers.
The study included more than 400 pregnant women enrolled in the Project Viva cohort between 1999 and 2002. The researchers assessed associations between blood levels of six PFAS chemicals during early pregnancy and measures of cardiometabolic health three years after birth. Measures included levels of blood biomarkers linked to cardiometabolic health, blood pressure, and body measurements, such as waist and arm circumference.
Higher PFAS levels during pregnancy were associated with higher cardiometabolic risk three years after giving birth, indicated by changes in cardiometabolic biomarkers, higher blood pressure, and greater body measurements. Specifically, perfluorooctanoic acid was linked to greater arm circumference and body mass index. Perfluorooctanesulfonic acid was associated with higher blood pressure. The PFAS chemical 2-(N-ethyl-perfluorooctane sulfonamide) acetic acid was associated with higher cardiometabolic risk across both blood biomarkers and body measurements. According to the authors, results reinforce pregnancy as a sensitive window for maternal health.
Citation: Mitro SD, Sagiv SK, Fleisch AF, Jaacks LM, Williams PL, Rifas-Shiman SL, Calafat AM, Hivert MF, Oken E, James-Todd TM. 2020. Pregnancy per- and polyfluoroalkyl substance concentrations and postpartum health in Project Viva: A prospective cohort. J Clin Endocrinol Metab 105(9):e3415–e3426.
New framework helps researchers return results to participants
NIEHS grantees developed a framework and set of recommendations to help environmental health researchers return research results to study participants, a process called result report-back. According to the authors, report-back has the potential to improve environmental health education and communication and overall public health. Despite strong recommendations for report-back, researchers share results with study participants infrequently and inconsistently, the authors said.
To create the framework, the researchers used feedback from 35 community engagement practitioners who participated in a workshop at the 2018 NIEHS Partnerships for Environmental Public Health Annual Meeting. Workshop attendees responded to the prompt: “What are some specific issues that are relevant to reporting back research results to individuals or the larger community?” Participants then grouped similar responses and rated groups by importance to successful result report-back. The researchers used qualitative and quantitative methods to create a framework, called a concept map, to visualize relationships between responses.
Five themes emerged from this process. Listed from most to least important, the themes were: effective communication strategies, community knowledge and concerns, uncertainty, empowering action, and institutional review and oversight. Engaging community partners in the process of result report-back emerged as a unifying global theme. The researchers further examined responses and made recommendations to address challenges within and across themes.
Environmental health researchers and practitioners should address these five specific themes when planning and implementing their result report-back activities, say the authors.
Citation: Lebow-Skelley E, Yelton S, Janssen B, Erdei E, Pearson MA. 2020. Identifying issues and priorities in reporting back environmental health data. Int J Environ Res Public Health 17(18):6742.
(Megan Avakian is a science writer for MDB Inc., a contractor for the NIEHS Division of Extramural Research and Training.)