Utility of Total Desmosine as Biomarker for Chronic Obstructive Pulmonary Disease Patients

Abstract

Matrix degradation is a key feature of COPD, leading to lung destruction, emphysema and impaired pulmonary function. Desmosine and isodesmosine are elastin-derived cross linked amino acids whose urine levels are considered representative of elastin breakdown. However, there is a lack of biomarkers to measure disease activity and disease progression in COPD. Aim: This study was done to determine the utility of urine and blood desmosine as a biomarker in diagnosis of COPD patients and to evaluate their relationship with lung function parameters. Methods: The urine and blood desmosine levels were measured using validated isotope dilution liquid chromatography tandem mass spectrometry methods in 151 subjects including 101 COPD patients and 50 healthy control subjects. Results: The COPD patients had higher levels of u-desmosine and b-desmosine compared with healthy smokers and non-smokers. There was statistically significant difference in the mean levels of u-desmosine and b-desmosine between the different severity groups of the COPD patients. After adjustments for age, sex, and BMI; the concentrations of u-desmosine and b-desmosine were significantly correlated with FEV1s% and DLCO% (p<0.05) among the COPD patients. The elevation of b-desmosine levels above cutoff of 0.30 ng/ml was not specific for COPD and was found in 69% of all COPD patients. This cutoff value had a diagnostic sensitivity of 71% and specificity of 53%. Conclusions: This study has demonstrated that both u-DES and b-DES levels were significantly elevated among COPD patients. Also, u-DES or b-DES levels are correlated with COPD severity and some lung function parameters.