Assessment of plasma klotho concentration in stable COPD

Abstract

Introduction: Klotho protein is associated with the mechanism of aging. In mice, a decrease in Kotho gene expression promotes accelerated aging, while overexpression results in extended lifespan. Plasma level of the protein was found to be an independent predictor of mortality among the elderly. Extensive research has been focused on evaluating the potential utility of the protein as a biomarker in certain conditions. Although COPD is associated with accelerated aging of the lung, only a few klotho studies dealt with respiratory diseases. Aims: We aimed to measure the level of plasma klotho in stable COPD and to reveal possible correlations with clinical parameters in order to evaluate its potential as a biomarker of the disease. Methods: Blood samples were collected from 33 stable COPD patients (63.9±7.9 years (mean±SD), FEV 1 38.6±18.1%). Clinical parameters (smoking status, lung function, GOLD stage, BODE-index, quality of life, physical fitness) and blood gases were evaluated. Plasma klotho concentration was measured using ELISA. Results: Plasma klotho level of patients was 504.9±134.3 pg/ml (mean±SD). Surprisingly, statistical analysis did not reveal correlation with BODE-index (r=-0.07), FEV 1 (r=0.12) or any other clinical parameters. There was no significant difference between the level of klotho in smokers versus ex-smokers (510.3±98.8 vs. 508.6±159.3 pg/ml, p>0.05), and between GOLD stages either. Conclusions: Plasma klotho concentration can be reliably measured in stable COPD. Our results suggest that klotho should not be considered as a biomarker of stable COPD, however, further studies are warranted to uncover its potential role in lung pathophysiology.