Degradation of extracellular matrix components is central to many pathological features of chronic destructive lung disorders.
Desmosine and
isodesmosine are
elastin-derived cross-linked
amino acids whose urine levels are considered representative of
elastin breakdown. The aim of this study was to apply a novel methodology, based on high-performance capillary electrophoresis, to the quantification of
desmosine and
isodesmosine in 11 patients with stable
chronic obstructive pulmonary disease (
COPD), 10 with an exacerbation of
COPD, nine with alpha1-antitrypsin deficiency, 13 with
bronchiectasis, and 11 adults with
cystic fibrosis, in comparison to 24 controls. It was found that, in patients with stable
COPD, urinary
desmosine levels were higher than in controls (p=0.03), but lower than in
COPD subjects with an exacerbation (p< or =0.05). The highest
desmosine levels were found in subjects with alpha1-antitrypsin deficiency,
bronchiectasis and
cystic fibrosis (p<0.001 versus stable
COPD). In a short-term longitudinal study, five stable
COPD patients showed a constant rate of
desmosine excretion (mean coefficient of variation <8% over three consecutive days). In conclusion, the present method is simple and suitable for the determination of
elastin-derived cross-linked
amino acid excretion in urine, giving results similar to those obtained using other separation methods. In addition, evidence is presented that urinary
desmosine excretion is increased in conditions characterized by airway
inflammation, such as exacerbations of
chronic obstructive pulmonary disease,
bronchiectasis and
cystic fibrosis. Results obtained in subjects with alphal-antitrypsin deficiency suggest that this method might be used to evaluate the putative efficacy of replacement
therapy.