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Human lung injury following exposure to humic substances and humic-like substances
Citation:
Ghio, Andy AND M. Madden. Human lung injury following exposure to humic substances and humic-like substances. ENVIRONMENTAL GEOCHEMISTRY AND HEALTH. Lonsdale Press, Ltd., London, Uk, 40(2):571-581, (2018). https://doi.org/10.1007/s10653-017-0008-5
Impact/Purpose:
Exposures to particles which include humic acid and humic-like substances can are associated with human diseases. These can include sarcoidosis, idiopathic pulmonary fibrosis, and injury following air pollution. Recognition of the associations can expedite understanding of the pathogenesis of these diseases.
Description:
Abstract Among the myriad particles the human respiratory tract is exposed to, a significant number are distinctive in that they include humic substances (HS) and humic-like substances (HULIS) as organic components. HS are heterogeneous, amorphous, organic materials which are ubiquitous occurring in all terrestrial and aqueous environments. HULIS are a complex class of organic, macromolecular compounds initially extracted from atmospheric aerosol particles which share some features with HS including an aromatic, polyacidic nature. As a result of having a variety of oxygen-containing functional groups, both HS and HULIS complex metal cations, especially iron. Following particle uptake by cells resident in the lung, host iron will be sequestered by HS- and HULIS-containing particles initiating pathways of inflammation and subsequent fibrosis. It is proposed that (1) human exposures to HS and HULIS of respirable size (<10 µm diameter) are associated with inflammatory and fibrotic lung disease and (2) following retention of particles which include HS and HULIS, the mechanism of cell and tissue injury involves complexation of host iron. Human inflammatory and fibrotic lung injuries following HS and HULIS exposures may include coal workers' pneumoconiosis, sarcoidosis, and idiopathic pulmonary fibrosis as well as diseases associated with cigarette smoking and exposures to emission and ambient air pollution particles.
URLs/Downloads:
DOI: Human lung injury following exposure to humic substances and humic-like substances