asbestos--crocidolite and thiazolyl-blue

Mineral fibers are potential carcinogens to humans. In order to help clarify the etiology of the pathological effects of asbestos, cellular reactions to natural and synthetic asbestos fibers were compared using a lung alveolar cancer cell line (A549 epithelial cells), considered the first target of inhaled micro-environmental contaminants. Natural asbestos tremolite (NAT) fibers were collected from rocks in NW Italy. Synthetic asbestos tremolite (SAT) was iron-free and therefore considered as standard tremolite. Both fibers, subjected to mineralogical characterization by X-ray powder diffractometry, electron microscopy and energy dispersive spectrometry, fell within the definition of respirable and potentially carcinogenic fibers. Several signs of functional and structural cell damage were found after treatment with both fibers, documented by viability, motility, and morphological perturbations. Phalloidin labeling showed irregular distribution of cytoskeletal F-actin, whereas immunohistochemical investigations showed abnormal expression of VEGF, Cdc42, β-catenin, assessed as risks indicators for cancer development. Both fibers caused significant loss of viability, even compared to UICC crocidolite, but, while SAT fibers exerted a more direct cytotoxic effect, survival of damaged cells expressing high VEGF levels was detected after NAT contact. This in vitro pilot study outlines potential health risks of NAT fibers in vivo related to their iron content, which could trigger signaling networks connected with cell proliferation and neoplastic transformation.

Topics: Actins; Apoptosis; Asbestos; Asbestos, Amphibole; Asbestos, Crocidolite; beta Catenin; cdc42 GTP-Binding Protein; Cell Line, Tumor; Cell Survival; Cytoskeleton; Humans; Immunohistochemistry; Iron; Microscopy, Electron; Mitosis; Necrosis; Phalloidine; Pilot Projects; Tetrazolium Salts; Thiazoles; Time Factors; Vascular Endothelial Growth Factor A; X-Rays

The urgent need for toxicological studies on carbon nanotubes (CNTs) has arisen from the rapidly emerging applications of CNTs well beyond material science and engineering. In order to provide a basis for comparison to existing epidemiological data, we have investigated CNTs at various degrees of agglomeration using an in vitro cytotoxicity study with human MSTO-211H cells. Non-cytotoxic polyoxyethylene sorbitan monooleate was found to well-disperse CNT. In the present study, the cytotoxic effects of well-dispersed CNT were compared with that of conventionally purified rope-like agglomerated CNTs and asbestos as a reference. While suspended CNT-bundles were less cytotoxic than asbestos, rope-like agglomerates induced more pronounced cytotoxic effects than asbestos fibres at the same concentrations. The study underlines the need for thorough materials characterization prior to toxicological studies and corroborates the role of agglomeration in the cytotoxic effect of nanomaterials.

Topics: Asbestos, Crocidolite; Carbon; Cell Line, Tumor; Cell Survival; DNA; Hexoses; Humans; Materials Testing; Nanotubes; Polyethylene Glycols; Spectroscopy, Near-Infrared; Tetrazolium Salts; Thiazoles

The aim of the present research was to determine whether the recently identified and characterized new fibrous amphibole fluoro-edenite may induce a cytopathic response in cultured cells. The final goal was to gain suggestions on the potentiality of fluoro-edenite to be harmful to human beings. Epidemiological studies, in fact, have shown an excess of developing mesothelioma among residents in Biancavilla, a town in eastern Sicily located in the Etna volcanic area. Therefore, we treated human lung fibroblasts, human lung alveolar epithelial cancer cell line A549 and monocyte-macrophage cell line J774 with fluoro-edenite or crocidolite; the latter used as a highly toxic amphibole asbestos reference. Our results show that fluoro-edenite may induce functional modifications and affects some biochemical parameters in tested cell cultures in a concentration and time dependent manner. However, the observed functional modifications induced by fluoro-edenite are generally less dramatic than those induced by crocidolite and more evident on human lung alveolar epithelial cancer cell line A549 with respect to those obtained on human lung fibroblasts or monocyte-macrophage cell line J774. The sequence of the damage is hypothesised to be as follows: at increasing fluoro-edenite concentrations, and/or treatment times, the increase in reactive oxygen species (ROS) production could trigger significant DNA damage in cell cultures, concomitantly with drop in cell metabolism and increase in lactic dehydrogenase release. In conclusion, according to our data, fluoro-edenite appears as a probable carcinogenic agent, responsible for the high incidence of malignant pleural mesothelioma in Biancavilla.

Topics: Animals; Asbestos, Amphibole; Asbestos, Crocidolite; Cell Line; Cells, Cultured; Comet Assay; Cytotoxicity Tests, Immunologic; DNA; Epithelial Cells; Fibroblasts; Humans; Lung; Macrophages; Mice; Nitric Oxide Synthase; Nitric Oxide Synthase Type II; Reactive Oxygen Species; Tetrazolium Salts; Thiazoles

Buildings equipped with asbestos-containing material may release asbestos fibers, the toxicity of which remains uncertain because of the generally low dose level. In 22 air samples collected in a building the asbestos level ranged between 0 and 0.027 f/ml. Both chrysotile and amphiboles were found. There was no association between in vitro cytotoxicity on rat pleural mesothelial cells and asbestos content, but there was a significant correlation with the total amount of particulate material. Four samples exhibited an enhancement of DNA synthesis in cells arrested in G1 with 5 mM hydroxyurea. This is more likely related to the particulate matter associated with asbestos fibers.

Topics: Air Pollution, Indoor; Animals; Asbestos; Asbestos, Crocidolite; Asbestos, Serpentine; Cell Survival; Cells, Cultured; DNA; DNA Repair; Mutagens; Pleura; Rats; Tetrazolium Salts; Thiazoles