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Neue Aspekte zur Pathogenese der Asbestose

A multiplicity of etiologic factors can induce interstitial pulmonary fibrosis. For the pathological- anatomical diagnosis of asbestosis I-IV, histopathological and supplementary lung dust analyses are essential. Due to the fact that minimal asbestos-associated fibrotic changes in lung tissue are not detectable by computer tomography (CT or HRCT) or chest radiography, pathological-anatomical verification is needed for a valid diagnosis.
The pathological-anatomical diagnosis of asbestosis requires detection of an appropriate pattern of interstitial fibrosis and of asbestos bodies: both components must be present.
Quantitative lung dust analysis is the gold standard for the quantification of asbestos body concentration and, in combination with histological examination, it is an effective tool for evaluation of asbestos-associated lung fibrosis.
Asbestos is a commercial term used to describe a group of natural mineral fibres that share some physical properties. Asbestos is often described as durable fibres that, after inhalation, persist for many decades in the lung and cause diseases. But asbestos itself is not a single kind of mineral fibre. The term asbestos covers an inhomogeneous group of several different mineral fibres. For an understanding of the genesis of asbestosassociated diseases we must consider the differences between the two mineral groups chrysotile and amphibole asbestos. Chrysotile is a serpentine mineral that has been shown to differ markedly from amphibole asbestos. Chrysotile is rapidly eliminated from the lung whereas amphibole asbestos persists over decades. Fibre dose, fibre dimensions and fibre biopersistence are proposed to be the decisive factors in fibre toxicity. The biopersistence of synthetic mineral fibres has been shown to be a good predictor of their pathogenic potency.
Biopersistence studies have shown that chrysotile is cleared rapidly from the lung and accordingly has lower fibrogenic and carcinogenic potential than amphibole asbestos. There is new scientific evidence for the lack of fibrogenic potency of chrysotile (with the exception of overload situations) which is neither durable nor accumulated. The likelihood that chrysotile could exert a lasting or chronic biological effect (with the exception of overload situations) must be considered to be extremely low. Because chrysotile and amphibole asbestos often occur together at the workplace and/or because chrysotile is often contaminated with amphibole asbestos (tremolite), simultaneous occupational exposure to the two kinds of asbestos is frequent. Because contamination of chrysotile with amphibole asbestos cannot be excluded, a safe use of chrysotile is not possible and a worldwide ban is still a necessary objective.