Evaluation of the Pulmonary Toxicity of Ambient Particulate Matter From Camp Victory, Iraq

Abstract

Anecdotal reports in the press and epidemiological studies suggest that deployment to Iraq and Afghanistan may be associated with respiratory diseases and symptoms in U.S. military personnel and veterans. Exposures during military operations were complex, but virtually all service members were exposed to high levels of respirable, geogenic dust. Inhalation of other dusts has been shown to be associated with adverse health effects, but the pulmonary toxicity of ambient dust from Iraq has not been previously studied. The relative toxicity of Camp Victory dust was evaluated by comparing it to particulate matter from northern Kuwait, a standard U.S. urban dust, and crystalline silica using a single intratracheal instillation in rats. Lung histology, protein levels, and cell counts were evaluated in the bronchoalveolar lavage fluid 1–150 d later. The Iraq dust provoked an early significant, acute inflammatory response. However, the level of inflammation in response to the Iraq dust, U.S. urban dust, and Kuwait dust rapidly declined and was nearly at control levels by the end of the study At later times, animals exposed to the Iraq, U.S. urban, or Kuwait dusts showed increased small airway remodeling and emphysema compared to silica-exposed and control animals without evidence of fibrosis or premalignant changes. The severity and persistence of pulmonary toxicity of these three dusts from the Middle East resemble those of a U.S. urban dust and are less than those of silica. Therefore, Iraq dust exposure is not highly toxic, but similar to other poorly soluble low-toxicity dusts.

Effect of Silica Dust on Antioxidant Enzymes in Granite Workers

“…Similarly, Sakhvidi 18 in ceramic workers in Iran and reported that the MDA levels in workers exposed to silica were higher than controls. In vivo studies demonstrated that silicosis and heavy metals [19][20][21][22][23][24][25][26][27] induces oxidative stress, which enhances generation of ROS and enhanced ROS associated with elevated levels of lipid peroxidation and oxidative enzymes activities [28][29][30] .…”

Can Serum Chitotriosidase Levels, Immune, and Oxidative Stress Parameters Be Early Diagnostic Indicators in Patients With Silicosis?

“…In in vivo studies, it was shown that in silicotic lungs elevated ROS generation is associated with increased levels of oxidative enzyme activities and lipid peroxidation. 22,23 In another study examing antioxidant status, serum SOD activity, malondialdehyde (MDA), and glutathione (GSH) levels were reported to be significantly higher in silicosis patients compared with controls. 24 Coal workers with pneumoconiosis showed increased levels of SOD, GPx, and CAT compared with a control group.…”

“…In in vivo studies, it was shown that in silicotic lungs elevated ROS generation is associated with increased levels of oxidative enzyme activities and lipid peroxidation 22,23 …”

Distinguishing Smoking-Related Lung Disease Phenotypes Via Imaging and Molecular Features

“…Similarly, from an exposure standpoint, although we focused on tobacco smoke exposure for this work, future studies with more robust environmental and occupational exposure data, as well as longer term follow-up data, preferably starting in childhood, are needed to determine how these clusters relate to other potential etiologies of COPD. [56][57][58] In summary, in two distinct cohorts, clustering smokers with the use of quantitative CT imaging-based measures enabled the identification of three subgroups of disease that have organ-specific molecular correlates. Further work is needed to better understand the significance of these clusters, the pathophysiologic and molecular differences between them, and their potential usefulness for defining disease prognosis and management.…”