Mass Spectrometric Identification of Cardiac Troponin T in Urine of Patients Suffering from Acute Myocardial Infarction

Alexander Streng, Noreen van der Linden, Jordy M. M. Kocken, Otto Bekers, Freek Bouwman, Edwin Mariman, Steven Meex, Will Wodzig

Research output: Contribution to journalArticleAcademicpeer-review

Abstract

Background:
Because of its high cardiospecificity, cardiac troponin T (cTnT) is one of the first-choice biomarkers to diagnose acute myocardial infarction(AMI). cTnT is extensively fragmented in serum of patients suffering from AMI. However,it is currently unknown whether all cTnT is completely degraded in the body or whether some cTnT fragments can leave the body via urine.The aim of the present study is to develop a method for the detection of cTnT in urine and to examine whether cTnTis detectable in patient urine.

Methods:
Proteins in urine samples of 20 patients were precipitated using a cTnT-specific immunoprecipitation technique and a nonspecific acetonitrile protein precipitation. After in-solution digestion of the precipitated proteins, the resulting peptides were separated and analyzed using HPLC and mass spectrometry with a targeted selected ion monitoring assay with data-dependent tandem mass spectrometry(t-SIM/dd-MS2).

Results:
Thet-SIM/dd-MS2 assay was validated using a synthetic peptide standard containing 10 specific cTnTpeptides of interest and with purified human intact cTnT spiked in urine from healthy individuals. Using this assay, 6 different cTnT-specific peptides were identified inurine samples from 3 different patients,all suffering from AMI.

Conclusions:
We show here for the first time that cTnT can be present in the urine of AMI patients using a targeted LC-MS/MSassay.Whether the presence of cTnT inurine reflects a physiological or pathophysiological process still needs to be elucidated.
Original languageEnglish
Pages (from-to)857-867
Number of pages11
JournalThe Journal of Applied Laboratory Medicine
Volume2
Issue number6
DOIs
Publication statusPublished - May 2018

Keywords

  • ION MONITORING ASSAY
  • PROTEINS
  • RELEASE
  • SERUM
  • DEGRADATION
  • VALIDATION
  • PROTEOMICS
  • CLEARANCE
  • FRAGMENTS

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