Arginine-Proline Metabolism as a Mediator in the Association Between Coal Dust Exposure and Lung Function

Abstract

Objectives To investigate the mediating role of the activation degree of arginine-proline metabolism in the association of coal dust and decreased lung function. Methods Cumulative dust exposure (CDE) represented coal dust exposure, whereas the hydroxyproline-to-arginine concentration ratio (Hyp/Arg) in bronchoalveolar lavage fluid gauged arginine-proline metabolism activation. Pulmonary function indicators, including predicted value of forced vital capacity (FVC%pred), forced expiratory volume in 1 second/forced vital capacity (FEV1/FVC%), and the ratio of actual to predicted value of FEV1 (FEV1%pred), diffusing capacity of the lungs for carbon monoxide (DLCO%pred), difference value between alveolar air and arterial partial oxygen pressure (P(A−a) O2), and 6-minute walking distance test (6MWT), were assessed. Results Findings revealed a significant association between elevated CDE and increased Hyp/Arg, increased P(A−a) O2, decreased 6MWT, DLCO%pred, and decreased FVC%pred. However, no statistically significant association was found between CDE and FEV1%pred or FEV1/FVC%. The mediating effect of Hyp/Arg was significant for CDE’s impact on P(A−a) O2 and DLCO%pred but not on 6MWT and FVC%pred. Conclusions These results highlight the role of Hyp/Arg in mediating the association between CDE and lung function parameters, shedding light on potential therapeutic avenues for mitigating coal dust–induced lung function impairment.