Liquid chromatography-based determination of urinary free and total N(epsilon)-(carboxymethyl)lysine excretion in normal and diabetic subjects

• Published in: Journal of chromatography. B, Analytical technologies in the biomedical and life sciences Analytical technologies in the biomedical and life sciences, 2003-09, Vol.794 (2), p.273-280
• Main Authors: Friess, Ulrich, Waldner, Michaela, Wahl, Hans-Guenther, Lehmann, Rainer, Haring, Hans-Ulrich, Voelter, Wolfgang, Schleicher, Erwin
• Format: Article
• Language: English
• Subjects: Adult; Aged; Aminoacids, peptides. Hormones. Neuropeptides; Analytical, structural and metabolic biochemistry; Biological and medical sciences; Case-Control Studies; Chromatography, High Pressure Liquid - methods; Fundamental and applied biological sciences. Psychology; Glycated Hemoglobin A - analysis; Humans; Lysine - analogs & derivatives; Lysine - urine; Middle Aged; N(ϵ)-(Carboxymethyl)lysine; Proteins; Reproducibility of Results; Sensitivity and Specificity; Spectrometry, Fluorescence
• ISSN: 1570-0232; 1873-376X
• DOI: 10.1016/S1570-0232(03)00472-0

We propose a specific, reproducible and sensitive HPLC method for the determination of N(epsilon)-(carboxymethyl)lysine (CML) excreted in urine. Total CML was measured in acid hydrolysates of urine samples, while free CML was measured in acetonitrile-deproteinised urine samples using a RP-HPLC method with ortho-phtaldialdehyde (OPA)-derivatisation and fluorescence detection suited for automation. We compared the CML excretion of 51 non-proteinuric patients with diabetes mellitus (DM) (age 57±14 years, HbA1c 8.0±1.8%) to 42 non-diabetic controls (C) (age 45±17 years). The urinary excretion of total CML in diabetic patients was increased by ∼30% (DM: 0.58±0.21; C: 0.45±0.14 μmol/mmol creatinine; P