Oxidant Generation and Lung Injury after Particulate Air Pollutant Exposure Increase with the Concentrations of Associated Metals

Abstract

We tested the hypothesis that particulate air pollutants are associated with metals that have a capacity to transport electrons and that biologic activity of the particulates can correlate with the concentrations of these metals. The metals studied were titanium, vanadium, chromium, manganese, iron, cobalt, nickel, and copper. Measurements included ( 1 ) oxidized products of deoxyribose catalyzed by particulates, (2) induction of a neutrophilic alveolitis after particdate instillation, (3) increments in airway reactivity after particulate instillation, and (4) mortality after exposures to both dusts and a microbial agent. Employing 10 different dusts of either natural or anthropogenic origin, in vitro generation of oxi- ~ dized products of deoxyribose increased with ionizable concentrations of all metals, except for titanium, associated with the particles. After tracheal instillation of dust into rats, both the neutrophil influx and lavage protein increased with ionizable concentrations of these same metals. Changes in airway reactivity following instillation of dusts in rats alsoappeared to be associated with the ionizable concentrations of these metals. Similarly, mortality after injection of particles in mice with subsequent exposure to aerosolized Streptococcus zooepidemicus reflected metal concentrations. We conclude that particulate air pollutants are associated with metals which have a capacity to catalyze electron transfer. An in vitro measure of oxidant production increased with ionizable concentrations of the metals. Indices of in vivo lung injury also corresponded to concentrations of these same metals.

Biologic effects of oil fly ash.

“…Epithelial cells take up ROFA into pits/vesicles that appear to be clathrin-coated ( Figure 3A,B). The particle then generates oxygen-based free radicals to present an oxidative stress to the cell (11,12) comparable that in to acellular systems (9). This cellular production of oxidants can be inhibited by either the metal chelator deferoxamine or the antioxidants N-acetylcysteine and dimethylthiourea (DMTU).…”

“…ROFA is remarkable in its capacity to induce lung injury in experimental animal models (9). Because ROFA is rich in metals, with little organic component, it has been particularly useful as a surrogate for ambient air PM in studies of biologic effect, testing the hypothesis that metals mediate the biologic effects of air pollution particles.…”

In vitro cellular responses to silicon carbide particles manufactured through the Acheson process: Impact of physico-chemical features on pro-inflammatory and pro-oxidative effects

“…This SiC I atypical profile could be explained on the one hand by the presence of crystallized silica (quartz and cristobalite) with high free carbon levels, and on the other hand by its high content of iron impurities (Table 1) Governa et al, 2005;IARC, 1996). It has been well described in the literature that there is a relationship between the presence of surface transition metal ions (especially iron) and cellular responses (Fubini et al, 1995b;Pritchard et al, 1996;Aust et al, 2000), especially for free radical generation (Fubini and Hubbard, 2003;Fenoglio et al, 2001;van Maanen et al, 1999;Turci et al, 2011;Pourchez et al, 2012). Indeed iron is known to be a catalyst in the formation of several reactive oxygen species (Pierre and Fontecave, 1999) (Halliwell and Gutteridge, 1992).…”

Neurogenic Inflammation and Particulate Matter (PM) Air Pollutants

“…This complexity has hampered investigations into the culpable factor(s) of PM toxicity and suggests that PM may target a variety of pathways. Consequently, most experimental research has focused on the individual chemical components identi®ed on certain industrial PM such as transition metals (Hatch et al, 1985;Gilmour et al, 1996;Pritchard et al, 1996;Dreher et al, 1997;Carter et al, 1997;Gavett et al, 1997;Kadiiska et al, 1997;Dreher et al, 1998), biologicals (e.g. endotoxins, pollen) (Becker et al, 1996), and acidic components (Chen et al, 1992;Brauer et al, 1995;Lippmann and Thurston, 1996;Kimmel et al, 1997;Zelikoff et al, 1997;Gwynn et al, 2000).…”

“…ROFA is generated from the burning of low sulfur residual oil, and is composed primarily of highly soluble transition metals and sulfates (Henry and Knapp, 1980;Pritchard et al, 1996;Dreher et al, 1997). Although ROFA is atypical relative to ambient PM in terms of its chemical make-up and in the level of its associated in¯ammation in experimental models, it contains components (i.e.…”