The Effects of Ambient Particulate Matter on Human Alveolar Macrophage Oxidative and Inflammatory Responses

Epidemiologic and occupational studies demonstrated that ambient particulate matter (PM) and diesel exhaust particles (DEP) exert deleterious effects on human cardiopulmonary health, including exacerbation of pre-existing lung disease and development of respiratory infections. The effects of ambient PM on lung cell responsiveness are poorly defined. Human alveolar macrophages (AM) were exposed to SRM 1649 (Washington, DC, urban dust; UD), SRM 2975 (forklift diesel exhaust particles; DEP), and fine or coarse ambient PM collected in Chapel Hill, NC, during the late fall (November) and early summer (June) of 2001–2002. AM were subsequently incubated with lipopolysaccharide (LPS), phorbol myristate acetate (PMA), or calcium ionophore A23817 for 6 or 24 h after PM exposure. UD and DEP markedly suppressed release 24 h post-PM exposure. UD exposure significantly inhibited tumor necrosis factor (TNF)-α, interleukin (IL)-6, and IL-8 release after exposure to 10 ηg/ml LPS. DEP significantly suppressed only TNF-α an...