Analysis of the urinary peptidome associated with Helicobacter pylori infection

AIM: To investigate the relationship between urinary peptide changes and Helicobacter pylori (H. pylon) infection using urinary peptidome profiling. METHODS: The study was performed in volunteers (n = 137) who gave informed consent. Urinary peptides were enriched by magnetic beads based weak cation exchange chromatography and spectrums acquired by matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF) mass spectrometry (MS). ClinProTools bioinformatics software was used for statistical analysis and the recognition of peptide patterns. The marker peptides were identified by LTQ Obitrap XL tandem MS. RESULTS: Approximately 50 proteins or peptides which loaded onto the magnetic beads were detected by MALDI-TOF MS. By optimizing the parameters of the model, the Genetic Algorithm model had good recognition capability (97%) and positive predictive value (94%). Based on the model, 2 markers with molecular masses of 6788 and 1912 Da were found that differentiated between H. pylon positive and negative volunteers. The m/z 1912 sequence was parsed as SKQFTSSTSYN-RGDSTF. The peptide was identified as isoform 1 of the fibrinogen a chain precursor, whose concentration in urine was markedly higher in H. pylori infected volunteers than in H. pylori non-infected ones. CONCLUSION: The appearance of urinary fibrinogen degradation products is caused by an active H. pylori-induced process. (C) 2011 Baishideng. All rights reserved.