Ambient PM2.5 Exposure Up-regulates the Expression of Costimulatory Receptors on Circulating Monocytes in Diabetic Individuals

• Published in: Environmental health perspectives 2011-06, Vol.119 (6), p.778-783
• Main Authors: SCHNEIDER, Alexandra, ALEXIS, Neil E, DIAZ-SANCHEZ, David, NEAS, Lucas M, HARDER, Shirley, HERBST, Margaret C, CASCIO, Wayne E, BUSE, John B, PETERS, Annette, DEVLIN, Robert B
• Format: Article
• Language: English
• Subjects: Aged; Air; Amplification; Antigen Presentation - drug effects; Antigen-Presenting Cells - drug effects; Antigen-Presenting Cells - immunology; Antigens, CD - immunology; Biological and medical sciences; Body Mass Index; Circulating; Diabetes Mellitus, Type 2 - immunology; Diabetes Mellitus, Type 2 - physiopathology; Diabetes. Impaired glucose tolerance; Endocrine pancreas. Apud cells (diseases); Endocrinopathies; Environment. Living conditions; Environmental Exposure; Environmental pollutants toxicology; Etiopathogenesis. Screening. Investigations. Target tissue resistance; Female; Flow cytometry; Glutathione; Glutathione Transferase - metabolism; Glycated Hemoglobin A - genetics; Glycated Hemoglobin A - metabolism; Hemoglobin; Humans; Insulin; Lag time; Male; Medical sciences; Middle Aged; Monocytes - drug effects; Monocytes - immunology; Neutrophils - drug effects; Neutrophils - immunology; Particulate Matter - toxicity; Public health. Hygiene; Public health. Hygiene-occupational medicine; Seasons; Sensitivity analysis; Toxicology; Up-Regulation - drug effects; Weather
• ISSN: 0091-6765; 1552-9924
• DOI: 10.1289/ehp.1002543

Exposure of humans to air pollutants such as ozone and particulate matter (PM) may result in airway and systemic inflammation and altered immune function. One putative mechanism may be through modification of cell-surface costimulatory molecules. We examined whether changes in expression of costimulatory molecules on circulating cells are associated with ambient levels of fine PM [aerodynamic diameter ≤ 2.5 μm (PM2.5)] in a susceptible population of diabetic individuals. Twenty subjects were studied for 4 consecutive days. Daily measurements of PM2.5 and meteorologic data were acquired on the rooftop of the exam site. Circulating cell-surface markers that mediate innate immune and inflammatory responses were assessed by flow cytometry on each day. Sensitivity analysis was conducted on glutathione S-transferase M1 (GSTM1) genotype, body mass index, and glycosylated hemoglobin A1c (HbA1c) levels to determine their role as effect modifiers. Data were analyzed using random effects models adjusting for season, weekday, and meteorology. We found significantly increased monocyte expression (mean fluorescent intensity) of CD80, CD40, CD86, HLA-DR, and CD23 per 10-μg/m3 increase in PM2.5 at 2- to 4-day lag times after exposure. These findings were significantly higher in obese individuals, in individuals with HbA1c > 7%, and in participants who were GSTM1 null. Exposure to PM2.5 can enhance antigen-presenting cell phenotypes on circulating cells, which may have consequences in the development of allergic or autoimmune diseases. These effects are amplified in diabetic individuals with characteristics that are associated with insulin resistance or with oxidative stress.