Pulmonary absorption of metals: Influence of lung surfactant components on the bioavailability of inhaled metals

Abstract

Significant absorption of some metals may occur through inhalation, especially under occupational exposure. However, pulmonary exposure to metals is not restricted to workers and substantial levels of some metals may be recovered in indoor air. The pulmonary absorption and toxicity of metal compounds is highly influenced by their solubility in biological fluids. In the alveoli and the terminal bronchiols, metals are subjected to interaction with surfactant which is synthesized by the alveolar type II (ATII) cells and to some extent by bronchiolar Clara cells. Surfactant consists of a mixture of about 90% lipids and 10% proteins. Our research objectives are to estimate: i) how much surfactant components may modulate Cd, Ni, Pb and Hg uptake and toxicity in various lung cells types; ii) to what extent lung cells may adapt to chronic exposure and how compares adaptation mechanisms in different cell phenotypes.