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27-09-2011 | General practice | Article

Biomarkers predicting pneumoconiosis in coal miners discovered


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MedWire News: Increased levels of certain biomarkers may predict the onset of coal workers' pneumoconiosis (CWP), report researchers.

This study follows on from previous work showing that coal miners with CWP have increased levels of several inflammatory markers, including serum matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of metalloproteinase-9 (TIMP-9), compared with healthy miners.

Jimin Zou (Attached Kai Luan Hospital of North China Coal Medical College, Tangshan, China) and colleagues investigated whether circulating biomarkers in conjunction with markers of pulmonary function may also be raised in some asymptomatic miners, indicating a pre-clinical stage of CWP.

They recruited 34 miners with CWP, 24 asymptomatic miners, and 11 miners with minimal pulmonary symptoms to test links between changes in pulmonary function and biomarker levels. All the miners were nonsmokers and male.

As reported in the journal Environmental Health, the team found that markers of lung function, namely, the percentage predicted values for forced vital capacity (FVC), forced expiratory volume (FEV)1, forced expiratory flow (FEF) 50, FEF75, and FEF25-75 were all significantly decreased in miners with CWP. MMP-9, TIMP-9, interleukin-18R (IL-18R), and IL-13 were also significantly increased in these individuals.

In the asymptomatic miners, they found that increases in MMP-9 were associated with significantly decreased FVC% of predicted values.

In addition, serum levels of IL-18 showed a trend for positive association with all markers of lung function, and levels of IL-18R, soluble CD40, sCD40L, MMP-9, TIMP-9, and soluble intercellular adhesion molecule-1 showed a trend for inverse association with all lung function parameters in this group. However, these associations were not statistically significant.

Increased IL-13 levels were significantly correlated with decreased FEV1/FVC and FEF25 values in the miners with minimal pulmonary symptoms, and increases in MMP-9 were also associated with significantly decreased FVC values in these men.

MMP-9 seems to be the strongest indicator of lung injury in coal miners. Zou and team speculate: "If levels of MMP-9 were continually stimulated to increase, MMP-9 could induce inflammation by activating IL-1β, an auto-inducible cytokine central to the inflammatory reaction.

"These responses could participate in aberrant remodeling processes which damage the extracellular matrix and may result in lung injury."

They suggest: "The levels of MMP-9… and IL-13 may be monitored as possible markers to estimate or predict lung function changes in minimally symptomatic coal miners."

By Helen Albert

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