Quantification of free and total desmosine and isodesmosine in human urine by liquid chromatography tandem mass spectrometry: A comparison of the surrogate-analyte and the surrogate-matrix approach for quantitation

• Published in: Journal of Chromatography A Vol. 1326; pp. 13 - 19
• Main Authors: Ongay, Sara, Hendriks, Gert, Hermans, Jos, van den Berge, Maarten, ten Hacken, Nick H.T., van de Merbel, Nico C., Bischoff, Rainer
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier B.V 24-01-2014; Elsevier
• Subjects: Aged; Biological and medical sciences; Biomarkers - urine; Calibration; Case-Control Studies; Chromatography, Liquid; COPD; Desmosine; Desmosine - urine; Female; Humans; Internal standard; Investigative techniques, diagnostic techniques (general aspects); Isodesmosine - urine; Male; Medical sciences; Middle Aged; Pathology. Cytology. Biochemistry. Spectrometry. Miscellaneous investigative techniques; Peptides - urine; Pulmonary Disease, Chronic Obstructive - urine; Respiratory system; Surrogate analyte; Surrogate matrix; Tandem Mass Spectrometry; Validation; Validation; Desmosine; Surrogate matrix; Surrogate analyte; Internal standard; COPD; Biological fluid; Tandem mass spectrometry; Chemical analysis; Organic cation; Oxygen 18; HPLC chromatography; Biological marker; Oxygen Isotopes; Pyridinium compounds; Clinical biology; Bronchus disease; Chronic obstructive pulmonary disease; Labelled compound; Quantitative analysis; Human; Urine; Lung disease; Healthy subject; Respiratory disease; Coupled method; Elimination; Patient; α-Aminoacid; Position isomer; Analysis method; Comparative study
• ISSN: 0021-9673; 1873-3778
• DOI: 10.1016/j.chroma.2013.12.035

•Synthesis of deuterated- and 18O-labeled DES and IDS standards.•Method development for free and total DES and IDS analysis in human urine.•Full method validation according to FDA and EMA regulations.•Comparison of surrogate matrix and surrogate analyte approaches.•Validated method application to the analysis of clinical samples.
In spite of the data suggesting the potential of urinary desmosine (DES) and isodesmosine (IDS) as biomarkers for elevated lung elastic fiber turnover, further validation in large-scale studies of COPD populations, as well as the analysis of longitudinal samples is required. Validated analytical methods that allow the accurate and precise quantification of DES and IDS in human urine are mandatory in order to properly evaluate the outcome of such clinical studies. In this work, we present the development and full validation of two methods that allow DES and IDS measurement in human urine, one for the free and one for the total (free+peptide-bound) forms. To this end we compared the two principle approaches that are used for the absolute quantification of endogenous compounds in biological samples, analysis against calibrators containing authentic analyte in surrogate matrix or containing surrogate analyte in authentic matrix. The validated methods were employed for the analysis of a small set of samples including healthy never-smokers, healthy current-smokers and COPD patients. This is the first time that the analysis of urinary free DES, free IDS, total DES, and total IDS has been fully validated and that the surrogate analyte approach has been evaluated for their quantification in biological samples. Results indicate that the presented methods have the necessary quality and level of validation to assess the potential of urinary DES and IDS levels as biomarkers for the progression of COPD and the effect of therapeutic interventions.