title: Urinary peptides as a diagnostic tool for renal failure detected by matrix-assisted laser desorption/ionisation mass spectrometry: an evaluation of their clinical significance.
abstract: The development of new analytical methodologies related to the proteome for the evaluation of renal physiology and pathology is surely of wide interest for physicians, giving them new tools for monitoring complications associated with diabetes, such as end-stage renal disease. In the present study, the clinical significance of the urinary abundance of two peptides, SGSVIDQSRVLNLGPITR (the uromodulin precursor, m/z 1912) and IGPHypGPHypGLMGPP [present in the collagen-α-5(IV) chain precursor, m/z 1219], detected by matrix- assisted laser desorption/ionisation mass spectrometry (MALDI/MS) in microalbuminuric or nephropathic diabetic patients and in non-diabetic nephropathic patients was evaluated. A progressive increase in the abundance of the ion at m/z 1219 and a decrease in the abundance of the ion at m/z 1912 have been found in diabetic microalbuminuric, diabetic-nephropathic and nephropathic patients. Linear correlations are present between serum creatinine values and the abundances of the ions at m/z 1219 (positive correlation, r=0.3645, P<0.0001) and at m/z 1912 (negative correlation, r=-0.3053, P<0.0005). Correlations between the MALDI data and the estimated glomerular filtration rate were also found, while relationships with urinary albumin excretion were found only in sub-sets of patients. Analysis of receiver operating characteristic curves showed a sensitivity up to 96% and a specificity of up to 84% for the two ionic species, or their ratio, for distinguishing diabetic patients with different degrees of nephropathy from healthy subjects, proving that the urinary abundance of the two peptides at m/z 1219 and m/z 1912, determined with MALDI/MS, may be considered as a possible diagnostic tool for the determination of progression toward renal failure, also with the aim of monitoring kidney function, in diabetic patients.
authors.affiliation: Department of Medical and Surgical Sciences, University of Padova, Via Giustiniani 2, I-35100 Padova, Italy.
authors.forename: Annunziata
authors.initials: A
authors.lastname: Lapolla
authors.forename: Laura
authors.initials: L
authors.lastname: Molin
authors.forename: Roberta
authors.initials: R
authors.lastname: Seraglia
authors.forename: Annalisa
authors.initials: A
authors.lastname: Sechi
authors.forename: Chiara
authors.initials: C
authors.lastname: Cosma
authors.forename: Luciana
authors.initials: L
authors.lastname: Bonfante
authors.forename: Nino Christiano
authors.initials: NC
authors.lastname: Chilelli
authors.forename: Eugenio
authors.initials: E
authors.lastname: Ragazzi
authors.forename: Pietro
authors.initials: P
authors.lastname: Traldi
mesh_terms: D015415:Biomarkers / Q000652:urine; D006801:Humans; D010455:Peptides / Q000652:urine*; D051437:Renal Insufficiency / Q000175:diagnosis* / Q000652:urine*; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D015415:Biomarkers; D010455:Peptides