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Addition of calcite reduces iron's bioavailability in the Pennsylvania coals - potential use of calcite for the prevention of coal workers' lung diseases.

Authors
Zhang-Q; Huang-X
Source
J Toxicol Environ Health, A 2005 Oct; 68(19):1663-1679
NIOSHTIC No.
20029073
Abstract
In the present study, a hypothesis was tested that the addition of calcite into the Pennsylvania coals may reduce levels of bioavailable iron (BAI), an important component in the mixed coal dust that may contribute to coal workers' lung diseases. Predetermined proportions of calcite (0, 1, 2, 5, 10% w/w) were added into three PA coals. After suspending the mixtures in an aqueous phosphate solution (10 mM, pH 4.5), which mimics the phagolysosomal conditions of the cells, levels of pH as well as calcium ions (Ca2+) in the coals were increased in a calcite concentration-dependent manner. In contrast, levels of BAI (both Fe2+ and Fe3+) were decreased. The inhibitory effects of calcite on the bioavailability of iron in human lung epithelial A549 cells and primary rat alveolar macrophages (AMs) were also examined. It was found that levels of low-molecular-weight (LMW) iron were significantly decreased in both A549 cells and AMs treated with the 10% calcite-PA coal mixture compared to those treated with the PA coal alone, while calcite itself had no effect on intracellular LMW iron. Calcite also showed a significant inhibitory effect on PA coal-induced ferritin synthesis in A549 cells. Reverse-transcription polymerase chain reaction (RT-PCR) studies revealed that the iron-containing PA coal downregulated levels of transferrin receptor (TfR) mRNA in A549 cells, which was partially restored by the addition of calcite. Our results indicate that calcite can inhibit the bioavailability of iron in the iron-containing PA coals.
Keywords
Coal-workers; Coal-mining; Coal-miners; Lung-disease; Diseases; Coal-dust; Laboratory-animals; Animals; Animal-studies; Iron-compounds; Pulmonary-system-disorders; Respiratory-system-disorders; Occupational-diseases; Occupational-exposure; Pneumoconiosis
CODEN
JTEHD6
CAS No.
471-34-1
Publication Date
20051008
Document Type
Journal Article
Funding Amount
638746
Funding Type
Grant
Fiscal Year
2006
NTIS Accession No.
NTIS Price
Identifying No.
Grant-Number-R01-OH-003561
Issue of Publication
19
ISSN
1528-7394
Source Name
Journal of Toxicology and Environmental Health, Part A: Current Issues
State
NY
Performing Organization
New York University Medical Center, New York, New York
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