Alveolar Macrophage Interaction with Air Pollution Particulates

Abstract

We applied flow cytometric analysis to characterize the in vitro response of alveolar macrophages (AM) to air pollution particulates. Normal hamster AM were incubated with varying concentrations of residual oil fly ash (ROFA) or concentrated ambient air particulates (CAP). We found a dosedependent increase in AM-associated right angle light scatter (RAS) after uptake of ROFA (e.g., mean channel number 149.4 ± 6.5, 102.5 ± 4.1, 75.8 ± 3.5, and 61 .0 ± 4.6 at 200, 100, 50, and 25 mg/ml, respectively) or CAP. A role for scavenger-type receptors (SR) in AM uptake of components of ROFA and CAP was identified by marked inhibition of RAS increases in AM pretreated with the specific SR inhibitor polyinosinic acid. We combined measurement of particle uptake (RAS) with flow cytometric analysis of intracellular oxidation of dichlorofluorescin. Both ROFA and CAP caused a dose-related intracellular oxidant stress within AM, comparable to that seen with phorbol myristate acetate (PMA) (e.g., fold increase over control, 6.6±0.4, 3.6±0.4, 4.6 ± 0.5, 200 mg/ml ROFA, 100 mg/ml ROFA, and 10-7 M PMA, respectively). We conclude that flow cytometry of RAS increases provides a useful relative measurement of AM uptake of complex particulates within ROFA and CAP. Both ROFA and CAP cause substantial intracellular oxidant stress within AM, which may contribute to subsequent cell activation and production of proinflammatory mediators.

Meconium Inhibits Phagocytosis and Stimulates Respiratory Burst in Alveolar Macrophages

“…Oxidative injury resulting from AM stimulation is a component of the pathophysiology of several respiratory diseases (6,7) and may also be important in MAS. Exposure of AMs to various types of particulates, including bacteria such as Staphylococcus aureus (26) and Pneumocystis carinii (27), and other particles, including zymosan (28), asbestos fibers (29), and various environmental air pollution particles (30), have been shown to stimulate a respiratory burst response and production of ROS. However, the magnitude and the duration of the oxidative response after ingestion of particles is variable and may in part depend on the specific receptors that are ligated.…”

The role of oxidative stress in ambient particulate matter-induced lung diseases and its implications in the toxicity of engineered nanoparticles

“…Several cell types are involved in allergen sensitization and asthma pathogenesis, including antigenpresenting cells (APC), T-helper 2 (Th2) lymphocytes, IgE-secreting plasma cells, mast cells, eosinophils, neutrophils, mucus-secreting goblet cells, smooth muscle and endothelial cells. DEP can directly impact a number of the cells that play a role in the afferent or efferent immune response [25,[81][82][83][84][85][86][87]. Traditional adjuvants exert their effects on the afferent or early phase of the immune response, which implies possible effects on antigen presenting cells (APC) [88,89].…”

Biologic effects of oil fly ash.

“…The microscope and EDS systems were interfaced to an external Power Macintosh 8600 imaging system using 4pi Analysis spectral engine hardware (4pi Analysis Inc., Durham, NC) and NIST DTSA software (National Institute of Standards and Technology, Gaithersburg, MD) for digital image collection, X-ray spectrum acquisition, analysis, and preparation of X-ray maps. may contribute to cellular activation and production of proinflammatory mediators (19)(20)(21). The primary source of these oxidants is likely the NADPH oxidase activity in the alveolar macrophage itself.…”