Disrupted Nitric Oxide Metabolism from Type II Diabetes and Acute Exposure to Particulate Air Pollution

• Published in: PloS one Vol. 10; no. 12; p. e0144250
• Main Authors: Pettit, Ashley P, Kipen, Howard, Laumbach, Robert, Ohman-Strickland, Pamela, Kelly-McNeill, Kathleen, Cepeda, Clarimel, Fan, Zhi-Hua, Amorosa, Louis, Lubitz, Sara, Schneider, Stephen, Gow, Andrew
• Format: Journal Article
• Language: English
• Published: United States Public Library of Science 14.12.2015; Public Library of Science (PLoS)
• Subjects: Aged; Air Filters - utilization; Air pollution; Air Pollution - adverse effects; Air pollution measurements; Atmospheric pollution; Bioavailability; Cardiovascular disease; Diabetes; Diabetes mellitus; Diabetes Mellitus, Type 2 - metabolism; Endothelium; Endothelium, Vascular - metabolism; Exposure; Female; Filtration; Forearm; Health care; Health risk assessment; Health sciences; Heart attacks; Heart rate; Hospitals; Humans; Hyperemia; Inhalation Exposure - adverse effects; Ischemia; Male; Medical schools; Metabolism; Metabolites; Middle Aged; Nitrates; Nitric oxide; Nitric Oxide - metabolism; Nitrites; Nitrites - blood; Outdoor air quality; Oxidative stress; Oxidative Stress - physiology; Particulate Matter - toxicity; Particulates; Passengers; Physiology; Pollutants; Pollution; Pollution control; Population studies; Respiratory diseases; Smooth muscle; Toxicology; Traffic; Vehicle Emissions - toxicity; United States > US
• ISSN: 1932-6203; 1932-6203
• DOI: 10.1371/journal.pone.0144250

Type II diabetes is an established cause of vascular impairment. Particulate air pollution is known to exacerbate cardiovascular and respiratory conditions, particularly in susceptible populations. This study set out to determine the impact of exposure to traffic pollution, with and without particle filtration, on vascular endothelial function in Type II diabetes. Endothelial production of nitric oxide (NO) has previously been linked to vascular health. Reactive hyperemia induces a significant increase in plasma nitrite, the proximal metabolite of NO, in healthy subjects, while diabetics have a lower and more variable level of response. Twenty type II diabetics and 20 controls (ages 46-70 years) were taken on a 1.5 hr roadway traffic air pollution exposure as passengers. We analyzed plasma nitrite, as a measure of vascular function, using forearm ischemia to elicit a reactive hyperemic response before and after exposure to one ride with and one without filtration of the particle components of pollution. Control subjects displayed a significant increase in plasma nitrite levels during reactive hyperemia. This response was no longer present following exposure to traffic air pollution, but did not vary with whether or not the particle phase was filtered out. Diabetics did not display an increase in nitrite levels following reactive hyperemia. This response was not altered following pollution exposure. These data suggest that components of acute traffic pollution exposure diminish vascular reactivity in non-diabetic individuals. It also confirms that type II diabetics have a preexisting diminished ability to appropriately respond to a vascular challenge, and that traffic pollution exposure does not cause a further measureable acute change in plasma nitrite levels in Type II diabetics.