Toxicity and Carcinogenicity Mechanisms of Fibrous Antigorite

Abstract

We studied the effects of fibrous antigorite on mesothelial MeT-5A and monocyte-macrophage J774 cell lines to further understand cellular mechanisms induced by asbestos fibers leading to lung damage and cancer. Antigorite is a mineral with asbestiform properties, which tends to associate with chrysotile or tremolite, and frequently occurs as the predominant mineral in the veins of several serpentinite rocks found abundantly in the Western Alps. Particles containing antigorite are more abundant in the breathing air of this region than those typically found in urban ambient air. Exposure of MeT-5A and J774 cells to fibrous antigorite at concentrations of 5–100 μg/ml for 72 hr induced dose-dependent cytotoxicity. Antigorite also stimulated the ROS production, induced the generation of nitrite and PGE2. MeT-5A cells were more sensitive to antigorite than J774 cells. The results of this study revealed that the fibrous antigorite stimulates cyclooxygenase and formation of hydroxyl and nitric oxide radicals. These changes represent early cellular responses to antigorite fibers, which lead to a host of pathological and neoplastic conditions because free radicals and PGE2 play important roles as mediators of tumor pathogenesis. Understanding the mechanisms of the cellular responses to antigorite and other asbestos particles should be helpful in designing rational prevention and treatment approaches.

The impact of malignant pleural mesothelioma throughout Italy in the years 1995–2002: a geo-referenced study relating death rate to population distribution

“…All studies show rather low figures for MPM diffusion, and all state that no fibrous tremolite had ever been detected in chrysotile samples, but only small amounts (0.2-0.5 wt.%) of balangeroite, a non-regulated fibrous silicate, the biological effects of which where then poorly known and have been only preliminarily evaluated recently (Groppo et al 2005). Furthermore, there are indications of a widespread presence in the Balangero mine chrysotile asbestos of several other non-regulated asbestos-like minerals: (e.g., antigorite and diopside: Cardile et al 2007), and the puzzling ''polygonal serpentine'' (i.e., chrysotile that shows no rolled structure but develops as flat, sharply edged blades: Mellini 1986).…”

Asbestiformer Antigorit, ein Risikomineral in Serpentiniten: Argumente für eine Gesundheitsfürsorge entsprechend der Gruppe der Asbestminerale

“…Das bedeutende Gesundheitsrisiko von faserigem Antigorit wurde bereits von einer Reihe von Veröffentlichungen behandelt (Keeling et al [9]; Baumann [10]; Cardile et al [11]; Pugnaloni et al [12]; Wozniak et al [13,14] [16][17][18].…”

“…Entsprechende Gefährdungen werden unter Beschäftig-ten/Umwelt-Exponierten im Bereich der italienischen WestAlpen, wo Antigorit in Serpentiniten auftritt (Cardile et al [11], Pugnaloni et al [12]), sowie im Bereich des erwähn-ten australischen Steinbruchs angenommen (Keeling et al [7][8][9] …”

Evaluating asbestos fibre concentration in metaophiolites: a case study from the Voltri Massif and Sestri–Voltaggio Zone (Liguria, NW Italy)

“…During the past decades asbestos has known the degradation from one of the technologically most promising natural materials to a serious social and environmental problem. It is indeed nowadays widely accepted that the exposure to asbestos is related to serious pathologies of the lungs and pleura, like asbestosis, lung cancer and mesothelioma (see references in: Wagner et al 1960;Guthrie and Mossman 1993;Kamp and Weitzman 1999;Dearwent et al 2000;Browne and Wagner 2001;Van Gosen et al 2004;Gavett 2006;Groppo and Compagnoni 2007;Cardile et al 2007). The literature focussed on the genesis and characterisation of fibrous minerals and on their pathological interaction with the biosphere is rather rich and as a result, an ever increasing number of minerals and lithologies is now believed to represent a potential danger (as for amphiboles, see the review by Gunter et al 2007).…”

“…For incoherent materials containing [1 wt% of grains smaller than 2 cm, the asbestos concentration threshold is set at 1,000 mg/kg: over such a value, the material is classified as contaminated. The interaction mechanisms between fibres and lung cells and the question if there is a ''safe'' inhalation threshold for asbestos are however still debated (Cardile et al 2007).…”