title: Measurements of desmosine and isodesmosine by mass spectrometry in COPD.
abstract: OBJECTIVE
  Application of mass spectrometry (MS) for direct measurements of desmosine (D) and isodesmosine (I) in urine, plasma, and sputum as markers of elastin degradation in patients with alpha(1)-antitrypsin deficiency (AATD) and non-AATD-related COPD.
  
  
  BACKGROUND
  In COPD patients, the lungs undergo elastin injury, which can be monitored by measurements of D and I in body fluids as specific markers of elastin degradation using the specificity and sensitivity of MS.
  
  
  METHODS
  Acid hydrolysis of blood plasma, 24-h urine and sputum measurements, followed by chromatographic separation for mass spectrometric analysis.
  
  
  RESULTS
  Each patient group had levels of plasma D and I that were statistically significantly higher than those of control subjects. AATD patients had higher levels than COPD patients with normal alpha(1)-antitrypsin (AAT) levels. Twenty-four-hour urine measurements demonstrated no significant difference in total levels of D and I among control subjects and patients but showed a free (unbound) concentration of D and I in urine, which was statistically significantly higher in patients with COPD with and without AAT. The D and I levels in the sputum of patients with AATD exceeded the levels in COPD patients with normal AAT levels.
  
  
  CONCLUSIONS
  MS allows a sensitive and specific analysis of D and I in body fluids. The quantification of D and I in sputum, along with increases of D and I in plasma and an elevated free component of D and I in urine provide indexes that characterize patients with COPD and can be followed in relation to the course of the disease and/or therapy.
authors.affiliation: St. Luke's-Roosevelt Hospital, Department of Medicine, 1000 Tenth Avenue, Mara Center, New York, NY 10019, USA.
authors.forename: Shuren
authors.initials: S
authors.lastname: Ma
authors.forename: Yong Y
authors.initials: YY
authors.lastname: Lin
authors.forename: Gerard M
authors.initials: GM
authors.lastname: Turino
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003895:Desmosine / Q000032:analysis*; D004549:Elastin / Q000032:analysis; D005260:Female; D006801:Humans; D007524:Isodesmosine / Q000032:analysis*; D008297:Male; D013058:Mass Spectrometry; D016555:Matched-Pair Analysis; D008875:Middle Aged; D011379:Prognosis; D029424:Pulmonary Disease, Chronic Obstructive / Q000097:blood / Q000145:classification / Q000652:urine; D012680:Sensitivity and Specificity; D013183:Sputum / Q000737:chemistry; D019896:alpha 1-Antitrypsin Deficiency / Q000378:metabolism
chemical_list: D003895:Desmosine; D004549:Elastin; D007524:Isodesmosine