Summary and Synthesis of Part IV. Effects of Mineral Dusts on Cell Metabolism in Relation to Inflammation and Fibrogenesis (B)

Can one predict the fibrogenicity of minerals by evaluating the patterns of early lung injury by dusts? Do cell types other than the fibroblast play a role in the pathogenesis of fibrosis? Papers presented in this session addressed these questions while providing a link between in vitro and in vivo approaches. A central theme was the use of isolated cells and markers of cell damage in bronchial alveolar lavage (BAL) fluids from rodents exposed to dusts. In comparison to hyperoxia or intratracheal instillation of ferric oxide, instillation of silica into hamsters causes a dissimilar pattern of lung injury as indicated by differences in the distribution of 5 lactic dehydrogenase (LDH) isoenzymes in lavage fluid and serum (Dr. Brain). These studies suggest that LDH isoenzyme patterns can be used to differentiate various types and sites of pulmonary injury by toxic substances.