Changes in bronchoalveolar lavage indices associated with radiographic classification in coal miners

Previous studies on symptomatic coal miners have shown that alveolar macrop hages, recovered by bronchoalveolar lavage (BAL), release excessive amounts of reactive oxygen species (ROS) and inflammatory cytokines. It has been p roposed that these secretions may mediate cell injury and initiate the dise ase process. We hypothesized that acellular bronchoalveolar lavage fluid (B ALF) indices in coal miners chronically exposed to coal dust may reflect th e status of important homeostatic modulations in the lung that lead to the development of coal workers' pneumoconiosis (CWP). To test this hypothesis, we measured inflammatory status, oxidant burden, antioxidant defenses, cyt okines, growth factors, fibronectin, and alpha(1)-antitrypsin (alpha(1)-AT) in the BALF of healthy never-smoker control subjects, never-smoker undergr ound coal miners with negative radiographs (ILO 0/0-1/0), and two miners wi th moderate changes in the chest radiographs (ILO 2/2). Interestingly, indi ces of injury and inflammation increased with the progression of disease in coal miners. Antioxidant enzymes, such as catalase, glutathione peroxidase , and superoxide dismutase, showed a 19-fold, 22-fold, and 6-fold increase above control, respectively, in coal miners with category 2/2 CWP. Signific ant increases in the secretion of IL-1, IL-6, TNF-alpha, TGF-beta, fibronec tin, and alpha(1)-AT also were evident in coal miners with disease. This up -regulation of antioxidant defenses and cytokines was not evident in coal m iners in the absence of clinically evident radiographic disease. In additio n, the concentration of lipid peroxidation by products in the BALF of coal miners without evidence of radiographic disease showed a moderate 3-fold in crease, whereas, in coal miners with category 2/2 CWP it showed a 59-fold i ncrease compared to control subjects. These results are in good agreement w ith our hypothesis that development of CWP and its progression may be corre lated with an oxidative stress and up-regulation of cytokines and mediators of growth.