Asbestos Cell Injury Inflammation And Fibrotic Lung Disease

One interesting study is called, “Approaches to prevention of asbestos-induced lung disease using polyethylene glycol (PEG)-conjugated catalase” - Journal of Free Radicals in Biology & Medicine - Volume 2, Issues 5-6, 1986, Pages 335-338 by Brooke T. Mossman, Joanne P. Marsh, David Hardwick, Rhonda Gilbert, Scot Hill, Ann Sesko, Marie Shatos, Jacqueline Doherty, Ann Weller and Michael Bergeron. Here is an excerpt: “Abstract - Asbestos-associated damage to cells of the respiratory tract in vitro can be prevented by the simultaneous addition of scavengers of active oxygen species to cultures. To determine if administration of scavenger enzymes to animals and humans is a plausible approach to the prevention of asbestos-induced lung disease, osmotic pumps were filled with various concentrations of PEG-coupled catalase and implanted subcutaneously into Fischer 344 rats over a 28-day period. At 3, 14, and 28 days after implantation of the pumps, the animals were evaluated for levels of catalase in serum and lung. In addition, lung tissue and lavage fluids were examined at 28 days for biochemical and morphologic indications of cell injury, inflammation, and fibrotic lung disease. At all time points examined, the administration of PEG-catalase caused a dosage-dependent increase in serum levels of catalase. The levels of lung catalase were evaluated at 28 days but not at earlier time periods. In comparison to control rats, the amounts of enzymes (lactic dehydrogenase, alkaline phosphatase), protein, and cells in lavage fluids from treated animals were unaltered. Moreover, the lungs showed no evidence of inflammation or fibrotic disease as determined by differential cell counts in lavage and measurement of hydroxyproline. These studies suggest that administration of PEG-catalase does not cause injury or other alterations in lung tissue and can be pursued as a feasible approach to prevention of asbestosis.”

Another study is called, “Prevalence of pleural calcification in persons exposed to asbestos dust, and in the general population in the same district” - Environmental Research - Volume 5, Issue 2, June 1972, Pages 210-216 by M. Navrátilb, a and F. Trippéb, a – Here is an excerpt: “Abstract - It is of interest whether pleural calcification is primarily the result of long years of exposure to asbestos dust or whether there are factors other than exposure to dust. We have investigated persons working for a long period in a plant processing asbestos products (chrysotile), persons without occupational exposure to dust but living in the vicinity of the plant, and consanguineous relations of patients with pleural calcifications. We have also studied a large population above the age of 40, in the district in which the plant is situated. Comparison of the groups disclosed that prevalence of pleural calcifications was closely related to opportunity for exposure to asbestos dust either occupationally or by family or neighborhood contact, as contrasted with the unexposed population. The prevalence in the group with direct or indirect asbestos exposure was 5.3, 5.8, 3.5%; whereas in the unexposed population it was 0.34%. These results indicate that asbestos is primarily responsible for pleural findings, but that some pleural disease may be the result of the other factors, still not known. The identification of other causes is hampered by the long period which need elapse from the onset of the process to the radiological appearance of the pleural change.”

Another study is called, “Malignant pleural mesothelioma caused by environmental exposure to asbestos or erionite in rural Turkey: CT findings in 84 patients” by AA Sahin, L Coplu, ZT Selcuk, M Eryilmaz, S Emri, O Akhan and YI Baris Department of Chest Diseases, Hacettepe University, School of Medicine, Ankara, Turkey. - American Journal of Roentgenology, Vol 161, 533-537. Here is an excerpt: “OBJECTIVE Malignant pleural mesothelioma in rural Turkey frequently results from environmental exposure to tremolite asbestos or fibrous zeolite (erionite). The aim of this study was to determine the CT features of malignant pleural mesothelioma in patients exposed to asbestos or erionite. MATERIALS AND METHODS. The CT scans of 84 patients with proved malignant pleural mesothelioma were retrospectively evaluated. Twenty patients (24%) had been exposed to erionite and 64 patients (76%) had been exposed to asbestos. The CT scans were interpreted by seven observers who did not know the clinical or pathologic findings. RESULTS. CT scans showed either unilateral pleural thickening or pleural nodules/masses in all patients. Pleural nodules were present in 25 patients (30%) and pleural masses in 44 patients (52%). Pleural effusion was found in 61 patients (73%), mediastinal pleural involvement in 78 (93%), pleural calcifications in 52 (62%), involvement of the interlobar fissures in 64 (76%), and volume contraction in 61 (73%). Reduced size of the hemithorax was significantly correlated with chest wall involvement. On the basis of CT findings, the preassigned staging was changed in 21 patients (25%), including 44% of the patients with disease that had been classified as stage I. CT findings were not significantly different between the patients exposed to erionite and those exposed to asbestos. CONCLUSION. The most common CT findings in cases of malignant pleural mesothelioma were unilateral pleural thickening or pleural nodules/masses with or without effusion. CT provided valuable information on the extent of the disease, which was important for staging. Although the CT features are not pathognomonic, they provide valuable clues to the diagnosis in patients who have been exposed to mineral fibers.”

If you found any of these excerpts interesting, please read the studies in their entirety. We all owe a debt of gratitude to these fine researchers.