Lung function changes in pleural asbestosis

The aim of this study was to examine the relationship between radiographically detectable pleural changes and lung function in pleural asbestosis. One hundred and twenty chrysotile asbestos-exposed workers were enrolled in this retrospective study. For each examinee the length of asbestos exposure and the degree of dust cover at the workplace were assessed as well as the radiological and functional tests has been performed. The examinees were divided into two groups based on radiologically detectable changes: a) group with pleural changes (29%) and b) group without perceived pleural changes (71%). The obtained results indicate association between the length of asbestos exposure, pleural changes and the impairment of lung function.     

Biomarkers in malignant mesothelioma: diagnostic and prognostic role of soluble mesothelin-related peptide

Soluble mesothelin-related peptide (SMRP) is a biomarker that has been proposed for differential diagnosis from pleural metastatic cancer, as well as prognosis and treatment monitoring of malignant pleural mesothelioma (MM). The aim of this study was to evaluate the role of SMRP in clinic management of MM. We assayed the SMRP concentrations in 354 subjects: 109 healthy volunteers with no history of exposure to asbestos, 26 patients with previous occupational asbestos exposure but who were free from pleural or parenchymal disease, 48 patients with asbestosis, 110 patients with pleural plaques, 25 patients with lung cancer, and 36 patients with MM. We also tested SMRP titers in 2 patients with MM at 5 different times of the disease, to evaluate the trend of the biomarker in the course of therapy. Our data confirm previous experiences with the use of SMRP as a diagnostic marker of MM. Low SMRP levels at diagnosis seem to have a positive prognostic significance.     

TGF-beta1 induces progressive pleural scarring and subpleural fibrosis

Pleural fibrosis is a misunderstood disorder which can cause severe restrictive lung disease with high morbidity and even mortality. The condition can develop in response to a large variety of diseases and tissue injury, among them infectious disease, asbestos, drugs, and radiation therapy. There is no efficient treatment to reverse established pleural fibrosis. TGF-beta1 is suspected, even if not proven, as a key cytokine in this process. In this study, we used adenoviral gene transfer of TGF-beta1 to the pleural mesothelium in rats. We show that local and transient TGF-beta1 overexpression induces homogenous, prolonged, and progressive pleural fibrosis without pleurodesis, associated with severe impairment of pulmonary function. We further demonstrate that pleural fibrosis can expand into the lung parenchyma from the visceral layer, but not into the muscle from the parietal layer. We provide evidence that matrix accumulation and fibrosis within the parenchyma evolved through a process involving "mesothelial-fibroblastoid transformation" and suggest that the pleural mesothelial cell may be an important player involved in the development of the subpleural distribution pattern known to be a hallmark of pulmonary fibrosis. This new model of pleural fibrosis will allow us to better understand the mechanisms of progressive fibrogenesis, and to explore novel antifibrotic therapies in the pleural cavity.     

Asbestos and lung cancer in Glasgow and the west of Scotland.

OBJECTIVE--To quantify the relation between lung cancer and exposure to asbestos in men in west Scotland and to estimate the proportion of lung cancer which may be attributed to exposure to asbestos. DESIGN--An ecological correlation study of the incidence of lung cancer in men and past asbestos exposure. The unit of analysis was the postcode sector. Correction was made for past cigarette smoking, air pollution, and deprivation. SETTING--The region covered by the west of Scotland cancer registry, containing 2.72 million people and including Glasgow and the lower reaches of the River Clyde, where shipbuilding was once a major industry. SUBJECTS--All men diagnosed with lung cancer between 1975 and 1984 whose residence at the time of registration was within the west of Scotland. MAIN OUTCOME MEASURE--The population attributable risk for asbestos related lung cancer. RESULTS--An estimated 5.7% (95% confidence interval 2.3 to 9.1%) of all lung cancers in men registered in the west of Scotland during the period 1975-84 were asbestos related, amounting to 1081 cases. CONCLUSIONS--A considerable proportion of cases of lung cancer in men in Glasgow and the west of Scotland from 1975 to 1984 were asbestos related. Most of these may not have been considered for compensation by the Department of Social Security. Given the very small annual number of recorded cases of asbestosis this condition is probably not a prerequisite for the development of asbestos related lung cancer. A heightened awareness of the increasing incidence of asbestos related neoplasms and their more thorough investigation are recommended.     

The fate of chrysotile-induced multipolar mitosis and aneuploid population in cultured lung cancer cells

Chrysotile is one of the six types of asbestos, and it is the only one that can still be commercialized in many countries. Exposure to other types of asbestos has been associated with serious diseases, such as lung carcinomas and pleural mesotheliomas. The association of chrysotile exposure with disease is controversial. However, in vitro studies show the mutagenic potential of chrysotile, which can induce DNA and cell damage. The present work aimed to analyze alterations in lung small cell carcinoma cultures after 48 h of chrysotile exposure, followed by 2, 4 and 8 days of recovery in fiber-free culture medium. Some alterations, such as aneuploid cell formation, increased number of cells in G2/M phase and cells in multipolar mitosis were observed even after 8 days of recovery. The presence of chrysotile fibers in the cell cultures was detected and cell morphology was observed by laser scanning confocal microscopy. After 4 and 8 days of recovery, only a few chrysotile fragments were present in some cells, and the cellular morphology was similar to that of control cells. Cells transfected with the GFP-tagged α-tubulin plasmid were treated with chrysotile for 24 or 48 h and cells in multipolar mitosis were observed by time-lapse microscopy. Fates of these cells were established: retention in metaphase, cell death, progression through M phase generating more than two daughter cells or cell fusion during telophase or cytokinesis. Some of them were related to the formation of aneuploid cells and cells with abnormal number of centrosomes.     

Fluoro-edenite fibres induce lung cell apoptosis: an in vivo study

We previously showed that apoptosis in the lungs of sheep exposed to fluoro-edenite fibres is induced via the receptor pathway. The present study was performed to gain further insights into the mechanisms of activation of programmed cell death induced by the fibres. Fluoro-edenite fibres are similar in size and morphology to some amphibolic asbestos fibres. They have been found in benmoreitic lavas, in the local stone quarry, in building materials and in road paving at Biancavilla, a town in eastern Sicily (Italy), where epidemiological surveys revealed a cluster of mortality from pleural mesothelioma. Inhalation of asbestos fibres can cause chronic inflammation and carcinogenesis. Since fluoro-edenite has been shown to activate the apoptotic process, we set out to characterise the expression of apoptosis-regulating proteins in fluoro-edenite-exposed lung disease and sought to determine if apoptosis results from fluoro-edenite exposure. Lung tissue from apparently healthy sheep habitually grazing near Biancavilla was processed for immunohistochemical localisation of bcl-2 and bax. Results showed epithelial and interstitial bax overexpression, especially in cells directly in contact with the fibres, and negative bcl-2 immunoexpression. TUNEL-positive cells were detected in alveoli and connective tissue. The integrity of alveolar epithelium and alveolar apoptosis are critical determinants in the pathways that initiate fibrogenesis in the lung and fibroblastic foci are usually found close to abnormal or denuded alveolar epithelium. Our results are consistent with the hypothesis that apoptosis is an important mechanism for removing cells with irreparable fluoro-edenite-induced genetic changes that predispose them to a neoplastic evolution.     

DNA-based sputum cell image analysis for lung cancer in a clinical setting

OBJECTIVE: To measure cell nuclei characteristics, previously reported to express probability for lung cancer, in subjects with different forms ofpulmonary disease and those without disease. STUDY DESIGN: Sputum and buccal cell samples were obtained from 846 patients without pulmonary disease, with nonmalignant disease, chronic obstructive pulmonary disease, asbestosis and lung cancer, stained for DNA, scanned by cytometer and scored. This was related to specificity and sensitivity for lung cancer. At score 4.5 sensitivity was 53.8% and specificity 70.9%. This score and higher were defined as high scores (HS) and used to compare groups with lung cancer and other pulmonary disease. RESULTS: Among subjects without disease, 21.1% had HS in sputum cells. Among those with nonmalignant pulmonary disease, 31.7% had HS, and among subjects with lung cancer, 53.8% had it. Repeated evaluations showed that about one third of those with HS on the first occasion were normal on repeat sampling. Among subjects without lung cancer, 33.8% of never-smokers had sputum cell HS compared to 22.7.2% among smokers. CONCLUSION: Results demonstrate that the DNA cellular characteristics on cytometry were more frequent among subjects with lung cancer but also among subjects with other pulmonary disease compared to subjects witbout pulmonary disease.     

Pleural fluid lysozyme in human disease.

A prospective study was conducted to define the content, significance, and source of lysozyme present in the pleural fluid in human diseases. The pleural fluid lysozyme activity is similar in various malignant and nonmalignant transudates and exudates, and is of limited diagnostic value. The pleural fluid activity correlated well with that of paired serum samples but it had poor correlation with the disease state, the pleural fluid granulocyte counts, and total white blood cell counts. The data suggest that the pleural fluid lysozyme may be derived primarily from the blood and that it is not the product of inflammatory or neoplastic cells in the fluid itself.     

Presence of simian virus 40 sequences in malignant mesotheliomas and mesothelial cell proliferations

Malignant mesotheliomas (MMs) are pleural‐, pericardial‐, or peritoneal‐based neoplasms usually associated with asbestos exposure. Mesothelial cells are biphasic and may give rise to epithelial and sarcomatous MMs. In addition, benign or atypical proliferations of mesothelial cells may occur in response to many stimuli. There have been recent reports of simian virus 40 (SV40) DNA large T antigen (Tag) sequences in pleural MMs. To further understand the relationship between SV40, MMs, and mesothelial proliferations, we studied 118 MMs from multiple sites in Germany and North America, including 93 epithelial pleural, 14 sarcomatous or mixed pleural MMs, and 11 peritoneal MMs. In 12 pleural MMs, adjacent noninvasive tumor foci were identified and studied separately. Information about asbestos exposure (detailed history and/or microscopic examination for asbestos bodies) was available from 43 German patients. In addition, 13 examples of reactive mesothelium and 20 lung cancers from the United States were tested. DNA was extracted from frozen tumor and adjacent nontumorous tissues or after microdissection of archival formalin‐fixed, paraffin‐embedded microslides. Two rounds of PCR were performed with primers SVFor 3 and SVRev, which amplify a 105 bp region specific for SV40 Tag. The specificity of the PCR product was confirmed in some cases by sequencing. Our major findings were: 1) Specific SV40 viral sequences were present in 57% of epithelial invasive MMs, of both pleural and peritoneal origin. No significant geographic differences were found, and frozen and paraffin‐embedded tissues were equally suitable for analysis. 2) There was no apparent relationship between the presence of SV40 sequences and asbestos exposure. 3) SV40 sequences were present in the surface (noninvasive) components of epithelial MMs. 4) SV40 sequences were not detected in MMs of sarcomatous or mixed histologies. 5) Viral sequences were present in two of 13 samples (15%) of reactive mesothelium. 6) Lung cancers lacked SV40 sequences, as did non‐malignant tissues adjacent to MMs. Our findings demonstrate the presence of SV40 sequences in epithelial MMs of pleural and peritoneal origin and their absence in tumors with a sarcomatous component. Viral sequences may be present in reactive and malignant mesothelial cells, but they are absent in adjacent tissues and lung cancers. J. Cell. Biochem. 76:181–188, 1999. © 1999 Wiley‐Liss, Inc.     

Asbestos exposure induces alveolar epithelial cell plasticity through MAPK/Erk signaling

The inhalation of asbestos fibers is considered to be highly harmful, and lead to fibrotic and/or malignant disease. Epithelial-to-mesenchymal transition (EMT) is a common pathogenic mechanism in asbestos associated fibrotic (asbestosis) and malignant lung diseases. The characterization of molecular pathways contributing to EMT may provide new possibilities for prognostic and therapeutic applications. The role of asbestos as an inducer of EMT has not been previously characterized. We exposed cultured human lung epithelial cells to crocidolite asbestos and analyzed alterations in the expression of epithelial and mesenchymal marker proteins and cell morphology. Asbestos was found to induce downregulation of E-cadherin protein levels in A549 lung carcinoma cells in 2-dimensional (2D) and 3D cultures. Similar findings were made in primary small airway epithelial cells cultured in 3D conditions where the cells retained alveolar type II cell phenotype. A549 cells also exhibited loss of cell-cell contacts, actin reorganization and expression of α-smooth muscle actin (α-SMA) in 2D cultures. These phenotypic changes were not associated with increased transforming growth factor (TGF)-β signaling activity. MAPK/Erk signaling pathway was found to mediate asbestos-induced downregulation of E-cadherin and alterations in cell morphology. Our results suggest that asbestos can induce epithelial plasticity, which can be interfered by blocking the MAPK/Erk kinase activity.     

Use of mesothelial cell cultures to assess the carcinogenic potency of mineral or man made fibers

Natural mineral fibers may produce pulmonary cancers and mesothelioma. In contrast with lung cancer, the incidence of fiber-induced mesothelioma is not enhanced in smokers compared to non smokers. It is therefore of special interest to use mesothelial cells to study the toxicity of natural or man made mineral fibers. Several years ago, we have developed a method to culture rat pleural mesothelial cells (RPMC). We have first studied the effects of asbestos fibers by the application of in vitro tests formerly developed to determinedthe genotoxicity and transforming potency of soluble xenobiotics. Moreover, we have determined whether RPMC expressed cytochromes P450 known to metabolize polycyclic aromatic hydrocarbons. This paper reviews the results obtained so far. It has been found that asbestos fibers produced a cell transformation and a gentoxicity characterized by the formation of aneuploid cells, abnormal anaphases, chromosomal aberrations and DNA repair (UDS). In addition, RPMC expressed different forms of cytochromes P450. It is nowadays suggested that the tumorigenic potency of asbestos fibers may be related to the fiber dimensions, to their surface properties and in vivo biopersistence; this term involves the fiber solubility in biological medium and the fiber epuration from the lung by clearance mechanisms. Experiments are now in progress to determine whether the in vitro effects are dependent on the fiber parameters suggested as playing a role in the carcinogenic potency.Abbreviations B[a]P benzo[a]pyrene - CAs chromosomal aberrations - FBS fetal bovine serum - MM malignant mesothelioma - MMF man made fibers - MMMF man made mineral fibers - RPMC rat pleural mesothelial cell - TEM transmission electron microscopy - UDS unscheduled DNA synthesis - UICC Union Internationale Contre le Cancer     

The biomedical and epidemiological characteristics of asbestos-related diseases: a review

The purpose of this paper is to provide the reader with an overview of the biomedical and epidemiological characteristics of asbestos-related disease based upon currently available information. Epidemiological and experimental data developed over the past 20 years have greatly added to our knowledge of the biological effects of asbestos, particularly in relation to clinical disease. This information has substantially strengthened the evidence linking asbestos to specific health effects. Lung cancer and mesothelioma are clearly the most important asbestos-related causes of death among exposed individuals, although the accumulated data is suggestive of the existence of an excess risk of gastrointestinal and a variety of other neoplasms. Animal studies confirm the human epidemiological results and indicate that all commercially available fiber types are capable of producing lung cancer and mesothelioma. Experimental implantation and injection studies also show that the carcinogenicity of mineral fibers (including asbestos) is directly related to their dimensionality and not their chemical composition. Although the asbestos-related medical and scientific literature is voluminous, many issues related to the biological activity of asbestos fibers are as yet unresolved. Due to experimental and analytical limitations, questions concerning risk at low-level exposure, dose-response relationships, and individual susceptibility remain problematic.     

Pleural reactions to environmental agents.

In the past, pleural disease has been uncommon, generally limited to infection derived from underlying pulmonary involvement or the result of local neoplastic invasion or hematogenous metastases. The deep, protected location of the lung's mesothelial surface provides insufficient defense against environmentally derived very fine biologically active inorganic particles, and a new set of abnormalities--pleural plaques, fibrosis, unique calcification, malignancy (mesothelioma), benign asbestotic effusion--have introduced problems of pathogenesis, diagnosis, management, and therapy. These changes are becoming frequent among individuals who were exposed to asbestos more than 20 years ago. Occupational exposure (direct and indirect), and in some cases environmental exposure (household contacts of asbestos-exposed workers and factory neighborhood residents), have been associated with higher prevalence of radiographically evident pleural abnormalities. What effects such changes will have on morbidity and mortality rates is incompletely understood.     

Elemental Analysis of Histological Specimens: A Method to Unmask Nano Asbestos Fibers

There is an increasing amount of evidence that nanoparticles may enhance toxicological potential in comparison to the same material in the bulk form. The aim of this study was to develop a new method to unmask asbestos nanofibers from Formalin-Fixed Paraffin-Embedded (FFPE) tissue. For the first time, in this study we applied Energy Dispersive X-ray (EDX) microanalysis through transmission electron microscopy to demonstrate the presence of asbestos nanofibers in histological specimens of patients with possible occupational exposure to asbestos. The diagnostic protocol was applied to 10 randomly selected lung cancer patients with no history of previous asbestos exposure. We detected asbestos nanofibers in close contact with lung cancer cells in two lung cancer patients with previous possible occupational exposure to asbestos. We were also able to identify the specific asbestos iso-type, which in one of the cases was the same rare variety used in the workplace of the affected patient. By contrast, asbestos nanofibers were not detected in lung cancer patients with no history of occupational asbestos exposure.The proposed technique can represent a potential useful tool for linking the disease to previous workplace exposure in uncertain cases. Furthermore, Formalin-Fixed Paraffin-Embedded (FFPE) tissues stored in the pathology departments might be re-evaluated for possible etiological attribution to asbestos in the case of plausible exposure. Since diseases acquired through occupational exposure to asbestos are generally covered by workers’ insurance in most countries, the application of the protocol used in this study may have also relevant social and economic implications.Key words: Asbestos fibers, nanofibers, EDX microanalysis, Transmission Electron Microscopy, lung cancer, occupational exposure     

Cell protection, resistance and invasiveness of two malignant mesotheliomas as assessed by 10K-microarray

Malignant pleural mesothelioma (MPM) is an aggressive serosal tumor, strongly associated with former exposure to asbestos fibers and for which there is currently no effective treatment available. In human, MPM is characterized by a high local invasiveness, poor prognosis and therapeutic outcomes. In order to assess molecular changes that specify this phenotype, we performed a global gene expression profiling of human MPM. Using a 10,000-element microarray, we analyzed mRNA relative gene expression levels by comparing a mesothelioma cell line to either a pleural cell line or tumor specimens. To analyze these gene expression data, we used various bioinformatics softwares. Hierarchical clustering methods were used to group genes and samples with similar expression in an unsupervised mode. Genes of known function were further sorted by enzyme, function and pathway clusters using a supervised software (IncyteGenomics). Taken together, these data defined a molecular fingerprint of human MPM with more than 700 up- or down-regulated genes related to several traits of the malignant phenotype, specially associated with MPM invasiveness, protection and resistance to anticancer defenses. This portrait is meaningful in disease classification and management, and relevant in finding new specific markers of MPM. These molecular markers should improve the accuracy of mesothelioma diagnosis, prognosis and therapy.     

Bendectin and fetal malformations.

Mortality among 172 workers who received workmen''s compensation for asbestosis in Ontario was investigated and the causes of death were compared with those for the general male population in that province. The workers were found to have increased rates of death, relative to the general populations, for nonmalignant respiratory diseases, lung cancer and pleural and peritoneal mesothelioma. In comparison with the general population, the proportion of workers that survived was 69% of that expected 5 years after they were awarded compensation and 53% at 10 years.     

Malignant mesothelioma: facts, myths, and hypotheses

Malignant mesothelioma (MM) is a neoplasm arising from mesothelial cells lining the pleural, peritoneal, and pericardial cavities. Over 20 million people in the US are at risk of developing MM due to asbestos exposure. MM mortality rates are estimated to increase by 5–10% per year in most industrialized countries until about 2020. The incidence of MM in men has continued to rise during the past 50 years, while the incidence in women appears largely unchanged. It is estimated that about 50–80% of pleural MM in men and 20–30% in women developed in individuals whose history indicates asbestos exposure(s) above that expected from most background settings. While rare for women, about 30% of peritoneal mesothelioma in men has been associated with exposure to asbestos. Erionite is a potent carcinogenic mineral fiber capable of causing both pleural and peritoneal MM. Since erionite is considerably less widespread than asbestos, the number of MM cases associated with erionite exposure is smaller. Asbestos induces DNA alterations mostly by inducing mesothelial cells and reactive macrophages to secrete mutagenic oxygen and nitrogen species. In addition, asbestos carcinogenesis is linked to the chronic inflammatory process caused by the deposition of a sufficient number of asbestos fibers and the consequent release of pro‐inflammatory molecules, especially HMGB‐1, the master switch that starts the inflammatory process, and TNF‐alpha by macrophages and mesothelial cells. Genetic predisposition, radiation exposure and viral infection are co‐factors that can alone or together with asbestos and erionite cause MM. J. Cell. Physiol. 227: 44–58, 2012. © 2011 Wiley Periodicals, Inc.     

Redistribution of pulmonary EC-SOD after exposure to asbestos.

Inhalation of asbestos fibers leads to interstitial lung disease (asbestosis) characterized by inflammation and fibrosis. The pathogenesis of asbestosis is not fully understood, but reactive oxygen species are thought to play a central role. Extracellular superoxide dismutase (EC-SOD) is an antioxidant enzyme that protects the lung in a bleomycin-induced pulmonary fibrosis model, but its role has not been studied in asbestos-mediated disease. EC-SOD is found in high levels in the extracellular matrix of lung alveoli because of its positively charged heparin-binding domain. Proteolytic removal of this domain results in clearance of EC-SOD from the matrix of tissues. We treated wild-type C57BL/6 mice with 0.1 mg of crocidolite asbestos by intratracheal instillation and euthanized them 24 h later. Compared with saline- or titanium dioxide-treated control mice, bronchoalveolar lavage fluid (BALF) from asbestos-treated mice contained significantly higher total protein levels and increased numbers of inflammatory cells, predominantly neutrophils, indicating acute lung injury in response to asbestos. Decreased EC-SOD protein and activity were found in the lungs of asbestos-treated mice, whereas more EC-SOD was found in the BALF of these mice. The EC-SOD in the BALF was predominantly in the proteolyzed form, which lacks the heparin-binding domain. This redistribution of EC-SOD correlated with development of fibrosis 14 days after asbestos exposure. These data suggest that asbestos injury leads to enhanced proteolysis and clearance of EC-SOD from lung parenchyma into the air spaces. The depletion of EC-SOD from the extracellular matrix may increase susceptibility of the lung to oxidative stress during asbestos-mediated lung injury.     

Comprehensive proteome analysis of malignant pleural effusion for lung cancer biomarker discovery by using multidimensional protein identification technology

Malignant pleural effusion (MPE) obtained from lung adenocarcinoma may contain potentially useful biomarkers for detection of lung cancer. In this study, we used a removal system for high-abundance proteins followed by one-dimensional SDS-PAGE combined with nano-LC-MS/MS to generate a comprehensive MPE proteome data set with 482 nonredundant proteins. Next, we integrated the MPE proteome and secretome data sets from three adenocarcinoma cell lines, with a view to identifying potential PE biomarkers originating from malignant cells. Four potential candidates, alpha-2-HS-glycoprotein (AHSG), angiogenin, cystatin-C, and insulin-like growth factor-binding protein 2, (IGFBP2), were isolated for preclinical validation using ELISA. Both AHSG and IGFBP2 levels were increased in lung patients with MPE (n = 68), compared to those with nonmalignant pleural effusion (n = 119). Notably, the IGFBP2 level was higher in MPE, compared with that in benign diseases (bacteria pneumonia and tuberculosis pleuritis), and significantly associated with malignancy, regardless of the cancer type. Our data additionally support an extracellular function of IGFBP2 in migration in lung cancer cells. These findings collectively suggest that the adenocarcinoma MPE proteome provides a useful data set for malignancy biomarker research.